CN101424554B - Ultrasonic Flow Meter - Google Patents

Abstract

An ultrasonic flowmeter, comprising: a measurement flow channel (6), through which the fluid to be measured flows; ultrasonic transducers (8) and (9), respectively arranged at upstream ends opposite to each other along the measurement flow channel (6) and downstream ends; upstream eyelets (11) and downstream eyelets (12) for exposing ultrasonic transducers (8) and (9) to the measurement flow channel (6); first fluid suppressor (15), at least Adjacent to the downstream hole (12), it is used to reduce the fluid to be measured from flowing into the hole (12); the second fluid suppressor (16) is arranged at the upstream end of the measurement flow channel (6) and is opposite to the hole (11) and ( 12), used to reduce the measured fluid into the holes (11) and (12); the measurement control part (19), used to measure the propagation time of the ultrasonic wave between the ultrasonic transducers (8) and (9); and A calculation unit (20), used for calculating the flow rate according to the signal of the measurement control unit (19). The first flow suppressor (15) provided for the downstream aperture (12) comprises an aperture sealing member (21) having at least one ultrasonic transmission aperture (22). Therefore, it is possible to stabilize the fluid between the ultrasonic transducers so as to enhance the reception level of ultrasonic waves, thereby improving the measurement accuracy and the upper limit of flow rate measurement, and reducing the drive input to the ultrasonic transducers.

Description

Ultrasonic Flow Meter

This application is a divisional application of a Chinese patent application with application number 00805166.6 (international application number PCT/JP00/01689). The filing date of this Chinese patent application is March 17, 2000, and the title of the invention is "ultrasonic flowmeter". .

technical field

The invention relates to an ultrasonic flow meter, which uses ultrasonic waves to measure the flow and (or) flow velocity of gas or liquid.

Background technique

Ultrasonic flowmeters of this type already exist in the prior art, as disclosed in Japanese Patent Laid-Open No. 11-351926. As shown in Fig. 44, a kind of ultrasonic flowmeter comprises measuring tube 1, is used for allowing fluid to flow direction other end from one end, upstream ultrasonic transducer (upstream ultrasonic transducer) 2a and downstream (downstream ultrasonic transducer 2b. Upstream ultrasonic transducer 2a and the downstream ultrasonic transducer 2b pass through the measuring tube 1 that has a predetermined angle relative to the center line of the measuring tube 1. The upstream ultrasonic transducer 2a and the downstream ultrasonic transducer 2b are respectively installed in the recess 3a of the measuring tube 1 and 3b. The fluid fluctuation suppression part 5 is at the inlet end 4 of the measurement tube 1. The fluid flowing into the measurement tube 1 is adjusted by the fluid fluctuation suppression part 5 to reduce the inclination of the measurement part and/or suppress the generation of eddy currents, therefore, reduce the And/or changes in the ultrasonic reception level caused by ultrasonic waves at the interface where the refraction flow changes, thus avoiding the degradation of measurement accuracy.

Another known example is Japanese Patent Publication No. 63-26537. As shown in Fig. 45, a pair of ultrasonic transducers 2a and 2b are arranged oppositely at the upstream end and the downstream end of the surface of the measuring tube 1, respectively. The ultrasonic transducers 2a and 2b are installed in the recesses 3a and 3b of the measuring tube 1 respectively, and there is a large-capacity ultrasonic transmission part 3c in the cavity of each recess 3a and 3b to prevent fluid from entering the recesses 3a and 3b , providing high-precision flow measurement.

With the conventional structure as shown in Figure 44, the fluid fluctuation suppressing part 5 at the inlet end 4 of the measuring tube 1 can adjust the fluid flowing into the measuring tube 1 to reduce the inclination of the measuring part and/or suppress the generation of eddy currents, thereby reducing the Changes in the received level of ultrasonic waves caused by reflection and/or refraction of ultrasonic waves at the flow-changing interface reduce measurement distortion. However, as the flow velocity in the measuring tube 1 increases, the fluid flowing into the recesses 3a and 3b generates eddy currents, which increase the disturbance to the ultrasonic transducers 2a and 2b. As a result, reflection and/or refraction of ultrasonic waves at the eddy current changing interface increases, thereby lowering the ultrasonic reception level. Therefore, it is difficult to reduce the driving input of the ultrasonic transducers 2a and 2b.

Adopt the conventional structure as shown in Figure 45, the cavity place of each recess 3a and 3b has the ultrasonic transmission part 3c of large capacity, may cause the propagation loss of ultrasonic wave by the ultrasonic transmission part 3c of large capacity, therefore, reduces Ultrasonic output or ultrasonic receiving sensitivity. In addition, the ultrasonic waves pass through the solid body of the large-capacity ultrasonic transmission member 3c, which reduces the linear characteristics thereof, making it difficult to transmit ultrasonic waves to the opposite ultrasonic transducer. Therefore, it is difficult to reduce the power consumption of the flow meter, so it cannot be used as a device that can be used for a long time (for example, 10 years) with only a small amount of electricity, such as a flow meter for measuring the flow of gas (such as city gas or LPG) at home.

The present invention solves the above-mentioned problems. The purpose of the present invention is to reduce the fluid disturbance or vortex generated between the ultrasonic transducers to enhance the ultrasonic receiving level, thereby improving the measurement accuracy and the upper limit of flow measurement, and by reducing the drive of the ultrasonic transducer input to reduce power dissipation.

Contents of the invention

An ultrasonic flowmeter of the present invention comprises: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers are respectively arranged at the upstream end and the downstream end opposite to each other along the measurement flow channel; an upstream hole and a downstream hole for The ultrasonic transducer is exposed to the measurement flow channel; the first fluid suppressor, at least adjacent to the downstream hole, is used to reduce the flow of the measured fluid into the hole; the second fluid suppressor is arranged at the upstream end of the measurement flow channel and opposite to the The hole is used to reduce the fluid to be measured from flowing into the hole; the measurement control part is used to measure the propagation time of the ultrasonic wave between the ultrasonic transducers; and the calculation part is used to calculate the flow rate according to the signal of the measurement control part, wherein, is A first fluid suppressor disposed downstream of the aperture includes an aperture sealing member having at least one ultrasonic transmission aperture. Therefore, the fluid between the ultrasonic transducers can be stabilized to enhance the ultrasonic receiving level, thereby improving the measurement accuracy and the upper limit of the flow measurement, and by enhancing the ultrasonic receiving level, and by setting the fluid suppressor to improve the ultrasonic The attenuation reduces the drive input to the ultrasonic transducer.

Another ultrasonic flowmeter of the present invention includes: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers are respectively arranged at upstream and downstream ends opposite to each other along the measurement flow channel; an upstream hole and a downstream hole, Used to expose the ultrasonic transducer to the measurement flow channel; the first fluid suppressor and the second fluid suppressor, for the forward flow and the reverse flow of the measured fluid, are used to reduce the flow of the measured fluid into the hole; measure The control part is used to measure the propagation time of the ultrasonic wave between the ultrasonic transducers; and the calculation part is used to calculate the flow rate according to the signal of the measurement control part, wherein the first hole provided for the downstream end when the fluid flows forward The fluid suppressor is an aperture sealing member having at least one ultrasonic transmission hole; the second fluid suppressor is arranged at the inlet end and the outlet end of the measurement flow channel. Therefore, even when the fluid fluctuates and produces a momentary reverse flow, as in the case of forward flow, it is possible to reduce the flow of the measured fluid into the hole and remarkably reduce the fluid disturbance between the ultrasonic transducers, thereby improving the measurement accuracy and and the upper limit value for flow measurement.

Another ultrasonic flowmeter of the present invention includes: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers are respectively arranged at upstream and downstream ends opposite to each other along the measurement flow channel; The transducer is exposed to the hole of the measurement flow channel; the propagation channel flow regulator is arranged along the ultrasonic propagation channel between the upstream ultrasonic transducer and the downstream ultrasonic transducer and has a regulating part exposed to the fluid; the measurement control part , used to measure the propagation time of the ultrasonic waves between the ultrasonic transducers; the calculation component is used to calculate the flow rate according to the signal of the measurement control component. Therefore, the adjustment member of the propagation channel flow regulator provided directly above the upstream end of the ultrasonic propagation channel promotes fluid disturbance in the entire area passed from the upstream end to the downstream end of the ultrasonic propagation channel. Therefore, in the ultrasonic propagation channel, in the entire area through which the ultrasonic propagation channel passes along the width direction, from the area close to the upstream eyelet to the area close to the downstream eyelet, regardless of the flow rate, the entire width direction of the ultrasonic wave propagation channel The entire area, fluid Conditions are evenly disturbed, therefore, variations in correction coefficients over the entire flow measurement range can be reduced, errors due to correction coefficients can be avoided, and measurement accuracy can be improved. Therefore, even when the Reynolds number changes due to changes in the flow viscosity of the fluid, the measurement accuracy is stable, and the realized measurement device can withstand changes in the temperature of the fluid or changes in the composition of the fluid, thereby improving the practicability of the device.

Another ultrasonic flowmeter of the present invention includes: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers are respectively arranged at upstream and downstream ends opposite to each other along the measurement flow channel; A transducer is exposed to an aperture of the measurement flow path; a propagation path flow regulator disposed along an ultrasonic propagation path between an upstream ultrasonic transducer and a downstream ultrasonic transducer, having a regulating part exposed to the fluid; a fluid suppressor , used to reduce the fluid to be measured from flowing into the hole; the measurement control part is used to measure the propagation time of the ultrasonic waves between the ultrasonic transducers; and the calculation part is used to calculate the flow rate according to the signal of the measurement control part. Therefore, the adjustment member of the propagation channel flow regulator provided directly above the upstream end of the ultrasonic propagation channel promotes fluid disturbance in the entire area passed from the upstream end to the downstream end of the ultrasonic propagation channel. Therefore, in the ultrasonic propagation channel, in the entire area through which the ultrasonic propagation channel passes along the width direction, from the area close to the upstream eyelet to the area close to the downstream eyelet, regardless of the flow rate, the entire width direction of the ultrasonic wave propagation channel The entire area, fluid Conditions are evenly disturbed, therefore, variations in correction coefficients over the entire flow measurement range can be reduced, errors due to correction coefficients can be avoided, and measurement accuracy can be improved. In addition, a fluid suppressor can be provided for the hole that opens into the measurement flow channel to reduce the fluid flowing into the hole, thereby significantly reducing the fluid disturbance along the ultrasonic propagation channel between the ultrasonic transducers, and improving the flow measurement. Upper limit.

In one embodiment, the first flow inhibitor provided for the upstream bore is a deflector. Therefore, it is possible to reduce the propagation loss of the ultrasonic wave passing through the ultrasonic transmission hole for the upstream hole, thereby reducing the driving input to the ultrasonic transducer, and reducing the fluid flowing into the upstream hole, thereby stabilizing the fluid disturbance along the ultrasonic wave propagation channel and improving the measurement. precision.

In an embodiment, the first fluid suppressor provided for the upstream aperture is an aperture sealing member having at least one ultrasonic transmission aperture. Therefore, it is possible to remarkably reduce the flow of fluid into the upstream orifice and the downstream orifice, thereby increasing the upper limit value for flow measurement and improving measurement accuracy even for fluid accompanied by reverse flow. Also, ultrasonic transmission/reception with desired S/N characteristics can be achieved by significantly reducing fluid disturbance due to the perforation. Therefore, transmission output and drive input can be reduced, thereby reducing power consumption.

In an embodiment, the aperture ratio of the aperture sealing member provided for the upstream aperture is greater than the aperture ratio of the aperture sealing member provided for the downstream aperture. Therefore, the propagation loss of the ultrasonic wave can be reduced, thereby improving the upper limit value of the flow measurement and the measurement accuracy of the reverse fluid, and reducing the power consumption by reducing the driving input to the ultrasonic transducer.

In one embodiment, the propagation channel flow regulators are arranged at upstream and downstream ends relative to the ultrasonic propagation channel. Therefore, the ultrasonic propagation channel is surrounded by the upstream and downstream flow regulators, so that the disturbance conditions at the upstream and downstream ends of the ultrasonic propagation channel can be balanced, thereby further stabilizing the correction coefficient and improving measurement accuracy. In addition, the effect of flow conditions on the downstream end along the measurement flow path is reduced by the downstream propagation path flow regulator. Therefore, regardless of the condition of the piping at the downstream end of the measuring device, stable measurement can be achieved, thereby improving the degree of freedom in installation of the measuring device. In addition, the same effect is obtained for forward flow and reverse flow along the measurement flow path, and the correction coefficient can be stabilized even for fluctuating fluids, thereby improving measurement accuracy.

In one embodiment, the propagation channel flow regulators disposed on the upstream and downstream ends relative to the ultrasonic propagation channel are joined together by a connector part. Distance offsets between the flow regulators of the propagation channel or positional offsets between the upstream and downstream adjustment components are thus avoided and stabilized, thus reducing the variation of the measuring device. In addition, the connecting member reinforces the propagation channel flow regulator, which can reduce the size or thickness of the regulating member. Therefore, it is possible to make the flow condition in the ultrasonic propagation channel uniform or reduce the pressure loss in the measurement flow channel.

In one embodiment, the propagation channel flow regulator and the fluid suppressor disposed on the upstream end and the downstream end relative to the ultrasonic propagation channel are combined. Therefore, the positional relationship, such as the distance, between the upstream and downstream propagation path flow regulators and the fluid suppressor can be determined, thereby stabilizing the flow conditions. Therefore, changes in the flow conditions in the ultrasonic propagation channel can be reduced, enabling stable and little-changed measurement. Through this combination, the mechanical strength of the propagation channel flow regulator can be further increased, preventing deformation after long-term use, thereby improving its durability and reliability.

In one embodiment, the flow inhibitor is the first flow inhibitor provided for the downstream bore. Accordingly, the flow suppressor is provided due to the tendency for vortices to occur around the downstream orifice, since the downstream orifice extends at an acute angle with respect to the direction of flow. Therefore, the fluid flowing into the hole can be reduced, so as to effectively reduce the fluid disturbance between the ultrasonic transducers and increase the upper limit of flow measurement.

In one embodiment, the flow inhibitor is a first flow inhibitor provided for the upstream bore and the downstream bore. Therefore, it is possible to effectively reduce the disturbance in the hole, which constitutes a major part of the total flow disturbance in the ultrasonic propagation channel, thereby increasing the measurement accuracy and the upper limit value of the flow measurement.

In one embodiment, the fluid suppressor is a second fluid suppressor obtained by arranging a fluid suppressing member for a propagation channel flow regulator disposed along the ultrasonic propagation channel. Therefore, by combining the fluid suppressor and the propagation channel flow regulator, the variation in the suppression of the fluid flowing into the aperture can be reduced, thereby increasing the reliability and allowing for the provision of a small ultrasonic propagation channel. Therefore, the size of the measurement flow channel can be reduced.

In one embodiment, the fluid suppressor comprises a first fluid suppressor and a second fluid suppressor provided for the aperture, the second fluid suppressor being obtained by configuring the flow regulator of the propagation channel with a fluid suppressor member. Therefore, turbulence in the aperture is reduced by the multiplier effect of the first flow suppressor and the second flow suppressor, and by combining the flow suppressor and the propagation channel flow regulator, the suppression of fluid flowing into the aperture can be reduced changes in. Therefore, measurement accuracy and reliability can be increased. In addition, a small ultrasonic propagation channel can be provided. Therefore, the size of the measurement flow channel can be reduced.

In an embodiment, the first fluid suppressor is an aperture sealing member having at least one ultrasonic transmission aperture. Therefore, by covering the aperture with the aperture sealing member, the effect of inhibiting the fluid to be measured from flowing into the aperture can be further enhanced, thereby reducing and stabilizing the fluid in the aperture.

In one embodiment, the first fluid suppressor includes an aperture sealing member having at least one ultrasonic transmission aperture and a deflector disposed adjacent the aperture. Therefore, the effect of suppressing the fluid to be measured from flowing into the aperture can be further enhanced, thus increasing the measurement accuracy. In addition, by providing the deflector, it is possible to reduce the attachment of foreign matter such as dust to the hole sealing member. Therefore, the selection of the hole sealing part is mainly based on the transmission of ultrasonic waves without much consideration of the blockage of the hole sealing part, thereby increasing the freedom of selection. In addition, ultrasonic transmission capability can be enhanced to reduce power consumption, or sensitivity can be further increased to realize a measurement device with desired accuracy.

In an embodiment, the aperture ratio of the aperture sealing member provided for the upstream aperture is greater than the aperture ratio of the aperture sealing member provided for the downstream aperture. Therefore, the transmission loss of ultrasonic waves can be reduced, the upper limit value of flow measurement and the measurement accuracy of reverse flow can be improved, and the power consumption can be reduced by reducing the drive input to the ultrasonic transducer.

In one embodiment, the aperture sealing member is a mesh member of inclined mesh structure, having an inclination relative to the horizontal. Therefore, the structure is inclined with respect to the horizontal direction, which promotes the deposition of fine particles such as dust attached to the inclined mesh portion, thereby reducing the amount of such fine particle deposition and preventing clogging of the mesh member. Therefore, transmission of ultrasonic waves therein is ensured and stable measurement accuracy is maintained for a long period of time, improving reliability and durability.

In one embodiment, deflectors are provided at the upstream and downstream ends of the bore. Therefore, for both forward flow and reverse flow along the measurement flow path, measurement accuracy can be further improved, fluid flowing into the aperture is suppressed, and foreign matter is prevented from entering the aperture. Therefore, even for fluctuating fluids with reverse flow, stable measurement accuracy can be maintained for a long period of time, increasing reliability and durability.

In one embodiment, the distance between the flow regulator of the propagation channel and the ultrasonic propagation channel is changed according to the type of fluid to be measured. Therefore, the measurement flow path can be commonly used regardless of the type of the fluid to be measured, only the propagation path flow regulator is changed, thus improving convenience and maintaining stable measurement accuracy regardless of the fluid to be measured. Since the measurement flow channel can be commonly used, the cost can be reduced.

In one embodiment, the regulating part of the flow regulator of the propagation channel is a mesh-like structure. Therefore, the installation space of the flow regulator of the propagation channel with respect to the flow direction is reduced, and therefore, the size of the measurement flow channel is reduced.

In one embodiment, the regulating part of the flow regulator of the propagation channel is a structure of a grid part, and the wall surface thereof extends along the flow direction. Therefore, the flow direction can be adjusted by the wall extending along the flow direction, and the flow velocity distribution in the ultrasonic propagation channel can be further balanced to improve measurement accuracy.

In one embodiment, according to the position along the cross-section of the measurement flow channel, the interval between two adjacent adjustment components of the flow regulator of the transmission channel is changed. Therefore, the size of each adjustment member can be optimized according to the position along the cross-section of the measurement flow channel, while at the same time maintaining a reduced length of the adjustment member in the flow direction. Therefore, it is possible to further equalize the flow velocity distribution in the ultrasonic propagation channel and reduce the length of the adjustment member in the flow direction, thereby reducing pressure loss and improving measurement accuracy due to the equalization of the flow velocity distribution.

In one embodiment, the cross-section of the measurement flow channel in a direction perpendicular to the flow direction contains a rectangle. By using a rectangular section, it is possible to increase the measurement area relative to the total measurement cross-sectional area, thereby allowing for fluid measurement from the upstream end to the downstream end of the ultrasonic wave propagation channel under the same conditions. In addition, the two-dimensionality of the flow along the ultrasonic propagation channel can be increased, creating conditions for realizing the high-precision measurement of the average flow velocity of the fluid. In addition, the two-dimensionality of the flow is further increased by providing a second flow inhibitor.

In one embodiment, the cross-section of the measurement flow channel in a direction perpendicular to the flow direction comprises a rectangle with an aspect ratio smaller than 2. Therefore, there is no need to increase the aspect ratio to generate two-dimensional flow, and the specification of the cross section can be freely set according to the height of the flow channel to reduce the interference of reflected waves, thus creating conditions for improving the sensitivity of ultrasonic transmission/reception. In addition, by adjusting the measurement cross-section, the pressure loss in the measurement flow channel can be reduced, so the length of the contact fluid along the measurement cross-section is reduced without excessively smoothing the measurement cross-section.

In an embodiment, the aperture opening opens into the measurement flow channel and has the shape of a side extending in a direction substantially perpendicular to the direction of flow in the measurement flow channel. Therefore, transmission/reception of ultrasonic waves can be performed in a balanced manner with respect to the height direction of the measurement flow channel, and the aperture size of the holes in the measurement flow channel along the flow direction can be reduced. Therefore, the fluid disturbance caused by the hole can be further reduced, and the measurement accuracy can be further improved.

In one embodiment, the lead-in provided on the upstream end of the measurement flow channel is provided with a non-uniform flow suppressor having a channel opening with a small hole. Therefore, regardless of the shape of the flow channel or the pipe structure upstream of the measurement flow channel, a stable fluid can be supplied to the measurement flow channel, reducing fluid disturbance between ultrasonic transducers. Therefore, it is possible to further increase the upper limit value of the flow rate measurement, further improving the measurement accuracy. In addition, stable measurement can be achieved regardless of the shape of the flow channel or the piping structure upstream of the measurement flow channel, increasing the degree of freedom of installation of the measurement device.

In one embodiment, both the introduction portion provided at the upstream end of the measurement flow channel and the outlet portion provided at the downstream end of the measurement flow channel are provided with a non-uniform flow suppressor having a channel opening with a small hole. Therefore, it is possible to provide stable fluid entry into the measurement flow channel even when the measured fluid has a fluctuating flow accompanied by reverse flow, or the measured fluid has a fluctuating source at the upstream end. Therefore, the fluid fluctuation between the ultrasonic transducers can be reduced, the upper limit value of the flow measurement can be further increased, and the measurement accuracy can be further improved. In addition, stable measurement can be achieved regardless of the shape of the flow path, pipe structure, or source of fluctuation, upstream or downstream of the measurement flow path, thereby further improving the degree of freedom in installation of the measurement device.

In one embodiment, the cross-sectional area of the inlet or outlet is larger than the cross-sectional area of the measurement flow channel. Therefore, the installation cross-sectional area of the non-uniform flow suppressor can be increased, the pressure loss caused by the non-uniform flow suppressor can be reduced, and thus, the increase of pressure loss can be avoided. In addition, it is possible to increase the cross-sectional area of the introduction part or the outlet part, even when the pipe structure or the shape of the flow channel on the upstream and downstream ends changes, creating conditions for the installation of the measuring device without changing the introduction part or the outlet part. The shape of the exit section. Therefore, the degree of freedom of installation of the measuring device is increased.

In one embodiment, the pore size of the channel opening of the non-uniform flow suppressor is smaller than the pore size of the channel opening of the second flow suppressor. Therefore, even when the upstream or downstream connection port is provided with positional deviation, the fluid can flow uniformly in the measurement flow channel, thus increasing the measurement accuracy. In addition, even when the fluid to be measured fluctuates, the fluctuation of the fluid flowing into the measurement flow path can be reduced due to the small hole of the passage opening, so that the measurement accuracy can be improved even for a fluctuating flow. In addition, due to the small aperture size of the channel opening of the non-uniform flow suppressor, the amount of dirt/dust entering the measurement part can be reduced, increasing the reliability of the measurement operation along the measurement flow channel.

In one embodiment, another ultrasonic flowmeter includes: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers are respectively arranged at upstream and downstream ends opposite to each other along the measurement flow channel; upstream holes and A downstream hole is used to expose each ultrasonic transducer to the measurement flow channel; wherein at least one hole includes a plurality of isolated channels extending along the ultrasonic propagation direction. Therefore, there is little reduction in sensitivity due to ultrasonic waves propagating through the fluid in the isolated channel. In addition, due to the isolation of the channel, the linearity of the ultrasonic wave can be maintained to achieve the required reception and transmission. In addition, the orifice flow channel in the hole provided along the side of the flow channel is divided into small parts, so that vortex is less likely to occur, and the fluid flowing into the hole can be reduced. Therefore, even if fluctuations occur, the flow rate can be measured correctly.

In an embodiment, at least one aperture comprises a plurality of isolated channels extending in the direction of propagation of the ultrasonic waves. Thus, by means of the fluid suppressor, the flow of fluid into the orifice can be reduced, and the upper limit of the measurement can be improved. In addition, since the ultrasonic wave propagates through the fluid in the isolated channel, the reduction in sensitivity is small. In addition, due to the isolation of the channel, the linearity of the ultrasonic wave can be maintained, and the required reception and transmission can be realized. In addition, the orifice flow channel in the hole provided along the side of the flow channel is divided into small parts, so that the vortex is less likely to occur, and the fluid flowing into the hole can be further reduced. Therefore, even if fluctuations occur, the flow rate can be measured correctly.

In one embodiment, each isolation channel has an inlet surface extending along the vibrating surface of the ultrasonic transducer and an outlet surface extending along the wall of the measurement flow channel. Therefore, since the ultrasonic wave can enter the isolation channel at right angles and travel in a straight channel, the ultrasonic propagation channel has no reflection and little attenuation. In addition, since the outlet is a smooth surface relative to the wall of the flow channel, there is no disturbance in the flow in the peripheral layer along the wall of the flow channel. In addition, since the exit surface is adjusted as a radiation surface, ultrasonic waves can be radiated efficiently.

In one embodiment, each isolation channel of one eyelet extends co-linearly with a corresponding one of the isolation channels of the other eyelet. Thus, the mutual alignment of the transmitting surface and the receiving surface in the direction of propagation of the ultrasonic waves reduces the attenuation of reflections due to the partitions in the isolated channels of the opposing bores.

In one embodiment, one side of the longitudinal section of each isolation channel is longer than half the wavelength of the ultrasonic waves used for transmission/reception. Therefore, the viscous effect of the isolation surface is reduced, and an isolation channel with small attenuation can be provided.

In an embodiment, one side of the longitudinal section of each isolation channel is not an integer multiple of half wavelength of the ultrasonic wave used for transmission/reception. Therefore, transverse resonance can be suppressed and efficient propagation can be achieved.

In an embodiment, the distance between the isolation channel of the hole and the vibration surface of a corresponding ultrasonic transducer is an integer multiple of the half-wavelength of the ultrasonic wave. Therefore, resonance can be provided at half wavelength, thereby providing efficient radiation.

In an embodiment, the thickness of each partition of the isolation channel is smaller than the wavelength of the ultrasonic waves used for transmission/reception. Therefore, reflection of ultrasonic waves can be avoided, providing efficient ultrasonic transmission/reception.

In one embodiment, the isolation channels are formed by installing a honeycomb grid in the perforations. therefore. By using a grid, each eyelet can be divided vertically and horizontally.

In one embodiment, one of the isolation channels is open in the middle of the bore. Thus, the aperture is aligned to the middle of the ultrasonic transducer, providing efficient transmit/receive.

In one embodiment, the channel length of each isolation channel is shorter than the wavelength of the ultrasonic waves used for transmission/reception. Therefore, an ultrasonic propagation path with little attenuation can be provided.

In one embodiment, the isolation channel is formed by arranging a mesh member in the hole in a direction perpendicular to the propagation direction of the ultrasonic waves. Therefore, the channel length can be reduced by dividing the perforations with the mesh member.

In one embodiment, each isolation channel includes a communication member at some point along its length for communicating the isolation channel with an adjacent isolation channel. Therefore, attenuation due to the partition can be reduced.

Description of drawings

1 is a cross-sectional view depicting the structure of an ultrasonic flowmeter according to Embodiment 1 of the present invention;

Figure 2 is a cross-sectional view depicting the first fluid suppressor shown in Figure 1;

Figure 3 is a cross-sectional view depicting another first fluid suppressor;

Figure 4 is a cross-sectional view of the structure of an ultrasonic flowmeter, depicting another first fluid suppressor;

5 is a sectional view depicting another first fluid suppressor according to Embodiment 1 of the present invention;

Figure 6 is a front view depicting another example of the aperture sealing member shown in Figure 4;

Figure 7 is a sectional view along the line A-A shown in Figure 1, depicting the measurement flow channel;

Figure 8 is a front view depicting the eyelet shown in Figure 6;

9 is a cross-sectional view depicting the structure of an ultrasonic flowmeter according to Embodiment 2 of the present invention;

Fig. 10 is a plan view depicting an introduction part according to Embodiment 2 of the present invention;

Figure 11 is a cross-sectional view along the line B-B shown in Figure 9, depicting the measurement flow channel;

12 is a cross-sectional view of the structure of an ultrasonic flowmeter, depicting another non-uniform flow suppressor;

13 is a cross-sectional view depicting the structure of an ultrasonic flowmeter according to Embodiment 3 of the present invention;

14 is a cross-sectional view depicting another first fluid suppressor according to Embodiment 3 of the present invention;

15 is a cross-sectional view depicting the structure of an ultrasonic flowmeter according to Embodiment 4 of the present invention;

16 is a front view depicting a propagation channel flow conditioner viewed along the flow direction according to Embodiment 4 of the present invention;

Figure 17 depicts the correction factor characteristics without the propagation channel flow regulator of Figure 15;

Fig. 18 depicts the correction coefficient characteristics when there is a propagation channel flow regulator according to Embodiment 4 of the present invention;

19 is a cross-sectional view depicting another propagation channel flow conditioner according to Embodiment 4 of the present invention;

20 is a cross-sectional view of the structure of an ultrasonic flowmeter, depicting another propagation channel flow conditioner according to Embodiment 4 of the present invention;

21 is a perspective view depicting another propagation channel flow regulator according to Embodiment 4 of the present invention;

Figure 22 is a cross-sectional view along the line A-A shown in Figure 20, depicting the propagation channel flow regulator;

Fig. 23 is a cross-sectional view depicting the location where the propagation channel flow regulator is placed;

Figure 24 is a perspective view depicting another propagation channel flow regulator;

Figure 25 is a perspective view depicting another propagation channel flow regulator;

Figure 26 is a front view depicting another propagation channel flow conditioner viewed in the direction of flow;

27 is a cross-sectional view depicting the structure of an ultrasonic flowmeter according to Embodiment 5 of the present invention;

28 is a cross-sectional view depicting a fluid suppressor according to Embodiment 5 of the present invention;

29 is a cross-sectional view depicting another fluid suppressor according to Embodiment 5 of the present invention;

30 is a cross-sectional view depicting another fluid suppressor according to Embodiment 5 of the present invention;

31 is a cross-sectional view depicting another fluid suppressor according to Embodiment 5 of the present invention;

32 is a cross-sectional view of an ultrasonic flowmeter depicting another example according to Embodiment 5 of the present invention;

33 is a perspective view depicting another example of a fluid suppressor and a propagation channel flow regulator according to Embodiment 5 of the present invention;

34 is a sectional view depicting a flow channel of an ultrasonic flowmeter according to Embodiment 6 of the present invention;

35 is a cross-sectional view depicting an eyelet unit according to Embodiment 6 of the present invention;

36 is a cross-sectional view depicting the positional relationship between ultrasonic transducers facing each other according to Embodiment 6 of the present invention;

Figure 37 is a front view depicting the outlet surface of the first isolation channel according to Embodiment 6 of the present invention;

Figure 38 is a front view depicting the outlet surface of a second isolation channel according to Embodiment 6 of the present invention;

Figure 39 is a front view depicting the outlet surface of a third isolation channel according to Embodiment 6 of the present invention;

Figure 40 is a front view depicting the exit surface of an isolation channel according to Embodiment 6 of the present invention;

41 is a cross-sectional view depicting communication parts of an isolation channel according to Embodiment 6 of the present invention;

42 is a sectional view depicting another example of an isolation channel according to Embodiment 6 of the present invention;

Figure 43 is a front view depicting the exit surface of the isolation channel shown in Figure 42;

Figure 44 depicts the structure of a conventional ultrasonic flowmeter; and

Fig. 45 depicts another conventional ultrasonic flowmeter structure.

Detailed ways

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Example 1)

Fig. 1 is a sectional view illustrating the structure of an ultrasonic flowmeter according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 6 is a measurement flow channel surrounded by a flow channel wall 7, and reference numerals 8 and 9 are upstream and downstream ultrasonic transducers, respectively installed on the flow channel wall 7 and connected via a vibration conduction suppressor 10. make each other opposite. The distance between the upstream ultrasonic transducer 8 and the downstream ultrasonic transducer 9 is L, and the inclination angle with respect to the flow direction of the measurement flow channel 6 is θ. Reference numerals 11 and 12 are upstream and downstream holes for exposing the ultrasonic transducers 8 and 9 to the measurement flow channel 6, respectively. The holes 11 and 12 are both arranged in a recessed configuration in the flow channel wall 7 . Reference numeral 13 is an ultrasonic propagation path (represented by a two-dot chain line), along which ultrasonic waves emitted from one of the ultrasonic transducers 8 and 9 facing each other are directly propagated to the ultrasonic transducers 8 and 9. Another one of 9 without reflection from the wall. Reference numeral 14 is a first fluid suppressor provided for the upstream hole 11, used to reduce the measured fluid flowing into the upstream hole 11, and reference numeral 15 is a first fluid suppressor provided for the downstream hole 12, used for The flow of the measured fluid into the downstream orifice 12 is reduced. Reference numeral 16 is a second fluid suppressor provided at the upstream end of the ultrasonic propagation channel 13 for reducing the measured fluid flowing into the upstream and downstream holes 11 and 12 . The second flow suppressor 16 is mounted in a recess 7 a provided in the flow channel wall 7 .

FIG. 2 illustrates a first flow inhibitor provided for the downstream bore 12 . Reference numeral 21 is an aperture sealing member having a plurality of ultrasonic transmission holes 22 through which ultrasonic waves can be transmitted. The hole sealing member 21 is provided across the ultrasonic propagation path 13 so as to cover the hole 12 and extend on the same plane as the measurement flow path surface 6 a, thereby preventing the fluid to be measured from flowing into the hole 12 . Here, the hole sealing member 21 is net-shaped or the like, has a lot of ultrasonic transmission holes 22 through which ultrasonic waves can be transmitted, and is directly provided in a part of the measurement flow path surface 6a of the measurement flow path 6 corresponding to the hole 12. , and on the same plane as the measurement flow channel surface 6a so as not to disturb the fluid flow.

FIG. 3 illustrates a first flow inhibitor 14 provided for the upstream bore 11 . The first fluid suppressor 14 protrudes from the flow channel wall 7, and includes a flow guider 14a of a smoothly protruding structure and a guide surface 14b provided at an upstream end of the flow guider 14a, and has a smoothly increasing protrusion height.

The second fluid suppressor 16 has a direction adjusting part 16a and a fluctuation suppressing part 16b, the direction regulating part 16a is used to adjust the flow direction of the fluid to be measured, and the fluctuation suppressing part 16b is used to make the flow velocity distribution uniform or reduce the fluctuation of the fluid flow . The direction regulating member 16a includes a partition wall for dividing the cross section of the measurement flow channel 6 into small parts. The fluctuation suppressing member 16 b has a small length in the flow direction and has many minute transmission channels along the cross-section of the measurement flow channel 6 .

Reference numeral 17 is an upstream elbow part, which communicates with a control valve (not shown) arranged on the upstream end of the measurement flow path 6, and reference numeral 18 is a downstream elbow part, which communicates with a control valve (not shown) arranged along the measurement flow path 6. An outlet (not shown) at the downstream end of the channel 6 communicates. By using the elbow portions 17 and 18, the flow passage is provided in a small structure. Reference number 19 is a measurement control part connected with ultrasonic transducers 8 and 9, used to realize the sending and receiving of ultrasonic waves, and reference number 20 is a calculation part, which is used to calculate the flow velocity according to the signal sent by measurement control part 19, so that Calculate the flow rate.

The flow measurement operation using ultrasonic waves will be described below. With the function of the measurement control part 19 , ultrasonic waves are transmitted and received through the measurement flow channel 6 between the ultrasonic transducers 8 and 9 along the ultrasonic propagation channel 13 of the measurement flow channel 6 . In particular, the propagation time T1, ie the amount of time required for the ultrasonic waves emitted from the upstream ultrasonic transducer 8 to be received by the downstream ultrasonic transducer 9, is measured. The propagation time T2, ie the amount of time required for the ultrasonic wave emitted from the downstream ultrasonic transducer 8 to be received by the upstream ultrasonic transducer 9, is also measured.

The calculation unit 20 calculates the flow rate based on the measured propagation times T1 and T2 according to the calculation formula shown below.

Here, V represents the flow velocity of the fluid measured along the length direction of the measurement flow channel 6, θ represents the angle between the flow direction and the ultrasonic propagation channel, and L represents the distance between the ultrasonic transducers 8 and 9. For the distance, use C to represent the sound velocity of the measured fluid, and calculate the flow velocity V according to the following formula.

T1＝L/(C+Vcos θ)

T2＝L/(C—Vcos θ)

By subtracting the reciprocal of T1 from the reciprocal of T2, the speed of sound C can be removed from it, so that the following calculation formula can be obtained:

V＝(L/2cos θ)((1/T1)—(1/T2))

Since the values of θ and L are known, the flow velocity V can be calculated from the values of T1 and T2. Consider the measurement of air flow velocity, where angle θ=45 degrees, distance L=70 mm, sound velocity C=340 m/s, and flow velocity V=8 m/s. Then, T1=2.0×10-4 seconds and T2=2.1×10-4 seconds. Therefore, instant measurements are possible.

Next, by measuring the area S of the cross section of the flow channel 6 perpendicular to the flow direction, the flow rate Q can be obtained according to the following expression:

Q=KVS

where K is a correction factor determined due to the flow velocity distribution through the cross-section S.

Therefore, the flow rate is obtained by the calculating means 20 .

Next, the measurement flow path of this ultrasonic flowmeter and its measurement operation will be described. The fluid to be measured enters the measurement flow channel 6 and has uneven flow or fluid fluctuations due to the increase/decrease of the cross-sectional area provided in the flow channel by a control valve (not shown) that sets At the upstream end of the measurement flow channel 6 , or due to passing through the elbow portion 17 . Then, the direction is adjusted so that the fluid does not easily flow into the holes 11 and 12 by the direction adjusting part 16a of the second fluid suppressor 16 arranged at the upstream end of the ultrasonic propagation channel 13, so that the flow in the measurement flow channel 6 is adjusted and reduced. Small flow disturbances, meanwhile, disturbances due to fluctuations in the fluid caused by fluctuating fluids or the like are reduced by the fluctuation suppressing member 16b, so as to further suppress the flow of fluid into the holes 11 and 12. Then, the fluid enters the ultrasonic propagation channel 13 . The wave suppressing member 16b may be a mesh member, foamed member, microporous plate, non-woven fabric or the like, which has a large aperture ratio and can be set to have a small thickness in the flow direction. Therefore, the pressure loss can be reduced by the fluctuation suppressing member 16b, and therefore, the fluctuation in the fluid along the measurement flow path can be reduced without increasing the pressure loss. Furthermore, the fluctuation of the fluid in a region where the flow velocity is high can be reduced to suppress the fluctuation in the propagation time of the ultrasonic wave, so that the upper limit value for flow or flow velocity measurement can be increased and the measurement accuracy can be further improved.

Next, the hole 12 is opened before the downstream ultrasonic transducer 9, where strong eddy currents are prone to occur, because the hole 12 extends at an acute angle relative to the measurement flow channel, along the measurement flow channel surface 6a of the measurement flow channel 6 An aperture sealing member 21 (such as a net) is provided, which has a lot of ultrasonic transmission holes 22 that can transmit ultrasonic waves therefrom, and it is arranged along the measurement flow channel surface 6a of the measurement flow channel 6, so that the second fluid suppressor 16 The conditioned fluid is coplanar with the measurement flow channel surface 6a so as not to disturb the fluid. Therefore, the effect of suppressing the measured fluid from flowing into the downstream hole 12 can be further increased, and the eddies or fluid turbulence in the ultrasonic propagation channel 13 can be significantly reduced. On the other hand, for the upstream eyelet 11, the first fluid suppressor 14 is composed of a deflector 14a, and the deflector 14a is arranged near the upstream end of the eyelet 11 in a concave structure, so as to further reduce the flow of fluid into the eyelet 11, as shown in Figure 3 As indicated by the arrows in , thereby reducing fluid disturbances (such as vortices) and stabilizing the fluid. Since the direction in which the upstream hole 11 extends is at an obtuse angle with respect to the measuring flow channel 6, the intensity of any eddy current is smaller than that caused by the downstream hole 12, so the adverse effect is very small, and the first fluid suppressor 14 may not be provided. However, by providing the upstream bore 14 with a first flow inhibitor 14, the flow can be further stabilized. Moreover, the first fluid suppressor 14 can be integrally formed with the flow channel wall 7 in order to simplify the structure and reduce the cost.

Therefore, ultrasonic waves are transmitted and received between the ultrasonic transducers 8 and 9 along the ultrasonic propagation channel 13, and the fluid in the channel 13 is stable. Therefore, it is possible to increase the ultrasonic reception level, thereby realizing high-precision flow velocity measurement, and reducing the attenuation of ultrasonic waves caused by fluctuations in the fluid, thereby increasing the upper limit value for flow measurement.

Also, since the ultrasonic reception level can be improved by stabilization of the fluid, power consumption for ultrasonic transmission can be reduced. In addition, when the hole sealing member 21 is provided only for the downstream hole 12, the attenuation of ultrasonic waves passing through the hole sealing member 21 can be reduced, and the power consumption can be reduced by reducing the driving energy input to the ultrasonic transducers 8 and 9. Therefore, when a battery is used to drive the device, such as a gas meter for a home, it may be possible to continuously use the gas meter for a long period of time with only a small battery.

Fig. 4 is a sectional view of an ultrasonic flowmeter illustrating another first flow suppressor. Components and functions identical to those of the embodiments shown in FIGS. 1 to 3 are given the same reference numerals and will not be described in detail again, while components different from the above-mentioned embodiments will be described below. For the downstream aperture 12 , an aperture sealing member 21 a having an ultrasonic transmission hole 22 such as the member of the embodiment of FIG. 1 is provided as the first fluid suppressor 15 . Likewise, for the upstream aperture 11 , an aperture sealing member 21 b having an ultrasonic transmission hole 22 such as the member of the embodiment of FIG. 1 is provided as the first fluid suppressor 14 . These two hole sealing members 21a and 21b are arranged at positions that are on the same plane as the measurement flow path surface. Therefore, by providing the upstream orifice 11 and the downstream orifice 12 with the orifice sealing members 21a and 21b, respectively, the inflow of fluid into the orifices can be suppressed so as to avoid vortices or fluid turbulence, thereby improving measurement accuracy even for fluctuating fluids with momentary reverse flow. Improved accuracy is achieved. Moreover, the fluid disturbance in the holes 11 and 12 can be significantly reduced, and the refraction and (or) reflection of the ultrasonic wave due to any disturbance can be reduced, thereby realizing the ultrasonic wave with the required signal-to-noise ratio (S/N) performance. Transmit and receive, and reduce transmit output, which reduces drive input and therefore reduces power consumption.

Another embodiment of the hole sealing members 21a and 21b will be described below without referring to the drawings. Due to the obtuse angle of the upstream bore 11 with respect to the direction of extension of the measuring flow channel 6, the intensity of the eddy current is small. Therefore, even if the hole diameter ratio of the hole sealing member 21b provided in the upstream hole 11 is larger than that of the hole sealing member 21a provided in the downstream hole 12, a fluid suppressing effect can be expected. Therefore, in this embodiment, the upstream aperture sealing member 21b has an aperture ratio greater than that of the downstream aperture sealing member 21a. Since the area of each ultrasonic transmission hole of the upstream hole sealing part 21b is larger, the propagation loss of the ultrasonic waves is smaller than that of the downstream hole sealing part 21a. Therefore, when the aperture sealing members having the same aperture ratio are used at the upstream end and the downstream end, the propagation loss of ultrasonic waves can thereby be reduced, thereby reducing power consumption by reducing the driving input for the ultrasonic transducers.

FIG. 5 illustrates another embodiment of the first flow inhibitor 15 provided for the downstream bore 12 . Reference numeral 23 is a deflector, which is disposed near the upstream end of the downstream bore 12 and includes a bore sealing member 21 . The deflector 23 is arranged in the structure of a plate or a vane, which adjusts the direction of the fluid so that the fluid to be measured does not flow into the hole 12 . Accordingly, the aperture 12 is provided with an aperture sealing member 21 and a deflector 23 as a first flow inhibitor 15 .

For the bore 12 , the flow is redirected by a deflector 23 so as to reduce the amount of fluid flowing to the downstream bore 12 . Even if a small amount of fluid flows to the downstream hole 12, the fluid is prevented from flowing into the hole 12 by the hole sealing member 21, so as to avoid fluid disturbance (such as vortices) in the hole 12, and thus stabilize the fluid in the ultrasonic propagation channel 13, thereby further improving measurement accuracy . Moreover, since the flow guider 23 can be used to reduce the flow rate reaching the hole sealing member 21, even when the fluid to be measured contains fine particles of foreign matter (such as dust), the adhesion of foreign matter on the hole sealing member 21 can be reduced. . Therefore, the specifications of the hole sealing member 21 can be selected mainly in consideration of the transmission capability of ultrasonic waves, thereby improving the degree of freedom in the selection or setting therein. Moreover, the transmission capability of ultrasonic waves can be further improved to increase sensitivity, thereby reducing power consumption or improving accuracy. A similar structure can be used for the upstream bore 11 in order to further improve the measurement accuracy.

Figure 6 illustrates another embodiment of an aperture sealing member. Reference numeral 24 is a mesh member having ultrasonic transmission holes 22 arranged in a mesh structure. This mesh member 24 is provided on the aperture 12 as the aperture sealing member 21 along the measurement flow passage surface 6 a. Here, the flow direction of the fluid to be measured along the measurement flow path 6 is substantially horizontal, and the holes 11 and 12 are provided along the measurement flow path surface 6a, which is substantially vertical. For this arrangement of the measurement flow passage, the mesh member 24 is constituted by an inclined mesh portion 25 having an angle α with respect to the horizontal direction so that no mesh portion is provided in the horizontal direction.

When the fluid to be measured flows with fine particles of foreign matter such as dust contained therein, such foreign matter may adhere to the mesh member 24 provided in the downstream aperture 12 . However, since the mesh member 24 is constituted by the inclined mesh portion 25 having an inclination with respect to the horizontal direction, the attached fine particles of foreign substances easily slide down along the inclination. Therefore, clogging of the mesh member 24 due to deposition of attached fine particles of foreign matter can be avoided to ensure transmission of ultrasonic waves, thereby continuing stable measurement of the flow rate and flow velocity. Although the above description is directed to the downstream eyelet 12, the same applies to the upstream eyelet 11 as well.

FIG. 7 illustrates a cross-sectional view of the measurement flow path shown in FIG. 1 along line A-A. The cross section of the measurement flow channel 6 in the direction perpendicular to the fluid has a rectangle with a width W and a height H along the end faces of the ultrasonic transducers 8 and 9 arranged opposite each other. The measurement flow channel 6 is constituted by a flow channel wall 7 obtained by closely fitting a flow channel wall 7b having a recess and a flow channel wall 7c having a protrusion to each other. Since the cross-section is rectangular, a two-dimensional flow is realized in the measurement flow channel 6, and fluid fluctuations that may be generated in each corner portion of the rectangular cross-section are suppressed by the second fluid suppressor 16, thereby facilitating the measurement flow. Two-dimensional flow in channel 6. Moreover, since the height H of the measurement flow channel 6 between the ultrasonic transducers is constant, the ratio of the measurement region through which ultrasonic waves propagate with respect to the total cross-sectional area of the flow channel can be increased, thereby achieving the goal of measuring Create conditions for high-precision measurement of the average flow velocity of the fluid.

It will be appreciated that rectangular cross-section as used herein also includes a substantially rectangular shape with a rounded portion (corner R) in each corner of the rectangular cross-section to ensure that manufacturing equipment (e.g. when the flow channel wall 7 is The durability of the metal mold used when forming by die casting.

FIG. 8 illustrates the hole shape of the hole 12 provided along the measurement flow channel surface 6 a of the measurement flow channel 6 shown in FIG. 7 and having a rectangular cross section. The hole shape of the hole 12 along the surface 6a of the measurement flow channel has a rectangle, one side 12a of which extends through the measurement flow channel 6 in a direction substantially perpendicular to the direction of the fluid (shown by the arrow in the figure), and the other side 12b of which is at Extending in a direction substantially parallel to the direction of the fluid.

Therefore, in the measurement flow path 6, the hole 12 has a constant length to an arbitrary height in the direction of the fluid, as indicated by D in the figure, and therefore, ultrasonic waves can be sent and received in a balanced manner with respect to the height direction H, and thus The same measurement is realized through the measurement flow channel 6, thereby realizing high-precision measurement. Moreover, the length D of the hole along the flow direction is smaller than the length caused when the hole has a circular shape or an arc-shaped portion with the same area, so the fluid disturbance in the measurement flow channel 6 can be further reduced and (or) Fluid flows into the aperture 12, thereby improving measurement accuracy. Although the above description is directed to the downstream hole 12, it should be understood that the hole shape of the upstream hole 11 along the measurement flow channel surface 6a may also be rectangular in order to further improve the measurement accuracy.

As mentioned above, in the ultrasonic flowmeter of the present invention, the flow of the measured fluid into the hole 12 is reduced by at least the first fluid suppressor 15 provided for the downstream hole, so that the ultrasonic transducers 8 and 9 can be significantly reduced. Between the fluid disturbance, thus improving the measurement accuracy and the upper limit of the flow measurement. The first fluid suppressor 15 may be a hole sealing member 21, which has an ultrasonic transmission hole 22, so as to further increase the effect of inhibiting the fluid to be measured from flowing into the hole, thereby stabilizing the fluid in the hole. Moreover, although the propagation of ultrasonic waves can be guaranteed through the ultrasonic transmission holes 22, the hole sealing member 21 can only be provided for the downstream holes 12, so as to further reduce the attenuation of the ultrasonic waves, thereby reducing the driving input and power consumption of the ultrasonic transducers, and Improve measurement accuracy.

The first fluid suppressor 14 provided for the downstream aperture 11 includes an aperture sealing member 21 b having an ultrasonic transmission hole 22 . Therefore, the inflow of fluid into the upstream and downstream holes can be significantly reduced, thereby increasing the upper limit of flow measurement, and the measurement accuracy can be improved even for fluid accompanied by reverse flow.

The hole diameter ratio of the hole sealing member 21 b provided for the upstream hole 11 is larger than that of the hole sealing member 21 a provided for the downstream hole 12 . Therefore, the propagation loss of ultrasonic waves can be reduced, thereby improving the upper limit of flow measurement and the measurement accuracy of reverse flow, and reducing power loss by reducing the drive input to the ultrasonic transducer.

The first fluid suppressor 15 includes an aperture sealing member 21 having an ultrasonic transmission hole 22 and a deflector disposed near the aperture 11 or 12 . Therefore, the effect of suppressing the fluid to be measured from flowing into the hole can be further enhanced, thereby further improving the measurement accuracy. Also, by adopting the configuration of the deflector, it is possible to reduce the attachment of foreign matter such as dust to the hole sealing member. Therefore, the selection of the hole sealing member is mainly in consideration of the transmission capability of the ultrasonic wave, without much attention being paid to the blocking of the hole sealing member, thus increasing the degree of freedom of the selection. Also, it is possible to further increase ultrasonic transmission capability to reduce power consumption, or to further increase sensitivity to realize a device with required measurement accuracy.

The hole sealing member 21 is a mesh member having an oblique mesh pattern with an inclination relative to the horizontal direction. Therefore, the mesh structure is inclined with respect to the horizontal direction, so that fine particles such as dust attached to the inclined mesh portion 25 can be promoted to settle down, thereby reducing the deposition amount of such fine particles. Therefore, it is possible to ensure that ultrasonic waves propagate through them, and maintain stable measurement accuracy over a long period of time, thereby improving durability and reliability.

The cross-section of the measuring flow channel 6 in the direction perpendicular to the fluid therein has a rectangular shape. Therefore, by adopting a rectangular cross-section, it is possible to increase the measurement area relative to the total measurement cross-sectional area, thereby facilitating the measurement of fluid under the same conditions from the upstream end to the downstream end of the ultrasonic wave propagation channel 13 . Also, the two-dimensionality of the fluid along the measurement flow path 6 can be improved, thereby facilitating high-precision measurement of the average flow velocity of the fluid. Furthermore, by providing the second fluid suppressor 16, the two-dimensionality of the fluid can be further increased.

The opening of each of the holes 11 and 12 enters the measurement flow path 6 and is shaped to have a side extending in a direction substantially perpendicular to the direction in which fluid passes through the measurement flow path 6 . Therefore, it is possible to transmit/receive ultrasonic waves in a balanced manner with respect to the height direction of the measurement flow channel 6, and to shorten the aperture length of the holes in the flow direction in the measurement flow channel. Therefore, the fluid disturbance caused by the hole can be further reduced, thereby further improving the measurement accuracy.

The bent pipe portions 17 and 18 are bent in the direction of the width W of the measuring flow path 6, which is explained in the embodiment of the present invention. However, it should be understood that the curved tube portions 17 and 18 may optionally be bent in the direction of the height H of the measurement flow channel 6 or in any other direction, and that the curved tube portions 17 and 18 may be bent at different angles. Furthermore, the effect of inhibiting the flow of fluid into the apertures has been described as a function of the first fluid inhibitors 14 and 15 . However, it should be understood that it may also be desirable for the first fluid suppressors 14 and 15 to have an entrainment suppression effect to suppress when the fluid in the aperture is entrained by the fluid flowing through the measurement flow path due to its viscosity. Occasional vortices.

(Example 2)

Fig. 9 is a cross-sectional view illustrating the structure of an ultrasonic flowmeter according to Embodiment 2 of the present invention. In FIG. 9 , those parts and functions that are the same as those in the embodiments shown in FIGS. 1 to 8 use the same reference numerals and will not be described in detail again. The parts that are different from the above-mentioned embodiments will be collectively described as follows.

Reference numeral 26 is a non-uniform flow suppressor provided in an introduction portion 27 which is an inlet of the measurement flow passage 6 and has many fine passage openings 26a. When the fluid flowing into the introduction portion 27 has a deviation in its flow velocity distribution, the non-uniform flow suppressor makes the flow velocity distribution uniform before the fluid is sent into the measurement flow channel 6 . Reference numeral 28 is a valve unit which is connected to the upstream end of the elbow portion 17 and has a connection port 29 which is opened to the introduction portion 27 . The valve unit 28 is provided with a control valve 32 which has a valve seat 30 and a valve part 31 opposite the valve seat 30 . Reference numeral 33 is a fluid inlet provided at the upstream end of the valve seat 30, through which fluid flows in. Reference numeral 34 is an outlet unit, which is connected to the downstream end of the elbow portion 18 and has a fluid outlet 35 through which the fluid flows out. Reference numeral 36 is a spring for biasing the valve member 31 to the valve seat 30, and reference numeral 37 is a driving member, such as a solenoid or an electric motor, for driving the valve member 31 to open or close the control valve 32.

The operation of this ultrasonic flowmeter will be explained in the next step. When the control valve 32 is opened, the fluid to be measured flows in through the fluid inlet 33 , flows through the valve seat 30 and the connection port 29 , and flows into the introduction portion 27 . The fluid flowing into the introduction portion 27 has reduced uniformity in the flow direction and/or flow velocity distribution, and has non-uniformity (eg fluctuations) due to the piping structure upstream of the fluid inlet 33 and/or through the curved passage Influenced by the passage of the curved passage through the valve unit 28 . However, when the fluid flows through the fine passage opening 26a of the non-uniform flow suppressor 26 provided in the introduction portion 27, the non-uniformity in the flow direction and/or flow velocity distribution is improved, and the fluctuation of the fluid is reduced, A stable flow of fluid into the measurement flow channel 6 is thereby provided. As described above, in the measurement flow channel 6, the flow velocity distribution of the fluid passing through the cross section of the measurement flow channel 6 is made uniform by the direction adjustment member 16a of the second fluid suppressor 16, and the fluid is adjusted in direction so that the fluid There is less possibility of inflow into the holes 11 and 12, and fluid fluctuations are further reduced by the fluctuation suppression member 16b. Then, the fluid flows into the ultrasonic propagation channel 13 . In addition, the first flow suppressors 14 and 15 are positioned close to the upstream ends of the upstream and downstream bores 11 and 12, respectively, so as to reduce the flow of fluid into the bores 11 and 12. Therefore, by transmitting and receiving ultrasonic waves between the ultrasonic transducers 8 and 9 along the ultrasonic propagation path 13 , high-precision flow velocity measurement can be achieved, and the fluid is further stabilized in the ultrasonic propagation path 13 regardless of the upstream pipe structure. Furthermore, by reducing the attenuation of ultrasonic waves due to fluctuations in the fluid, the upper limit value for flow measurement can be further increased.

FIG. 10 is a plan view illustrating the introduction portion 27 . The installation position of the non-uniform flow suppressor 26 spans the entire area of the introduction portion 27 . Reference numeral 29a represents the first aperture position (represented by a two-dot chain line) of the connecting port 29, wherein the control valve 32 is arranged along the left and right direction of the figure (as shown in Figure 9), and the connecting port 29 is arranged at the On the left, reference number 29b indicates the second aperture position (represented by a two-dot chain line) of the connecting port 29, wherein the control valve 32 is arranged along the front and rear direction of FIG. 9, and the connecting port 29 is arranged on the opposite side of the figure. The cross-sectional area Sa of the introduction portion 27 is set larger than the cross-sectional area Sb of the measurement flow channel 6, which is defined as a rectangle with a width W and a height H (see FIG. 11) (Sa>Sb), so that The installation area for the non-uniform flow suppressor 26 is increased so that both the first aperture position 29 a and the second aperture position 29 b can be provided in the introduction portion 27 . Therefore, loss of the pressure of the measured fluid due to the non-uniform flow suppressor 26 can be reduced. In addition, even when the first and second aperture positions 29 a and 29 b have positional deviations with respect to the introduction portion 27 for various configurations/structures of the valve unit 28 , before the fluid flows into the measurement flow channel 6 , the flow is suppressed by non-uniform flow. The small channel opening 26a of the device 26 can make the fluid evenly distributed. Therefore, measurement accuracy can be ensured for measuring changes in the flow channel structure and/or piping structure upstream of the flow channel 6, such as the valve unit 28, so that the degree of freedom in installation can be improved.

Furthermore, as shown in FIG. 11 , the aperture size Ta of the passage openings 26 a (each having a small hole) of the non-uniform flow suppressor 26 is set smaller than the passage opening 16 c of the fluctuation suppressing member 16 b of the second flow suppressor 16 (Each has a small hole) Aperture size Tb (Ta<Tb). Thus, the non-uniform flow suppressor 26 is more functional than the second flow suppressor 16, capable of equalizing fluid fluctuations or deviations in flow velocity distribution. Therefore, by providing the non-uniform flow suppressor 26, a more stable flow of fluid into the measurement flow channel 6 can be provided. Therefore, even when the connection port 29 through which the fluid flows from the upstream end is deviated in position, by making the fluid flow into the measurement flow path 6 in a more uniform manner, measurement with increased accuracy can be achieved. Even when the incoming fluid fluctuates, the fluctuation of the fluid can be reduced, so that the measurement accuracy can be improved even for the fluctuating fluid. In addition, the aperture size of the channel opening 26a of the non-uniform flow suppressor 26 is set to be smaller than the aperture size of the channel opening 16c of the fluctuation suppressing member 16b of the second fluid suppressor 16, so that the amount of foreign matter entering the measurement flow channel 6 can be reduced (e.g. dirt or dust) in order to ensure proper measurement operation and increase reliability. Moreover, the cross-sectional area Sa of the non-uniform flow suppressor 26 is set larger than the cross-sectional area Sb of the measurement flow path 6, so the loss in the pressure of the fluid to be measured can be reduced, and even when the non-uniform flow suppressor 26 is on Avoid degradation of measurement indicators when foreign substances are attached.

FIG. 12 illustrates another embodiment of the non-uniform flow suppressor 26 . A first non-uniform flow suppressor 26 b is provided in the introduction portion 27 , and a second non-uniform flow suppressor 26 c is provided in the outlet portion 38 on the downstream end of the measurement flow passage 6 . The second non-uniform flow suppressor 26c includes many fine passage openings 26d as the first non-uniform flow suppressor 26b. With this structure, when there is fluid fluctuation or fluid deviation at the upstream end of the measurement flow path 6, the first non-uniform flow suppressor 26b provides the above-mentioned effect of reducing fluctuation and effect of suppressing non-uniform flow. When there is fluid fluctuation or fluid deviation at the downstream end of the measurement flow path 6, the second non-uniform flow suppressor 26c provides the effect of reducing fluctuation and the effect of suppressing non-uniform flow. Therefore, measurement accuracy can be improved and stable measurement can be achieved without paying attention to the flow channel structure and/or piping structure upstream or downstream of the measurement flow channel 6, thereby further improving the degree of freedom in installing the measurement device. Furthermore, even when momentary backflow is generated by fluctuations, measurement with increased accuracy can be achieved, and stable measurement can be achieved regardless of the position of the fluctuation source. In addition, the aperture size of the channel opening 26d of the second non-uniform flow suppressor 26c can be set to be smaller than the aperture size of the channel opening 16c of the second fluid suppressor 16, and (or) the cross-sectional area of the outlet portion 38 can be set To be larger than the cross-sectional area of the measurement flow passage 6 in order to provide the above-mentioned effect, as with the introduction portion 27 , the second non-uniform flow suppressor 26 c is provided at the outlet portion 38 . Therefore, measurement accuracy, degree of freedom in installation and/or reliability of the device against foreign matter can be improved.

As described above, in the ultrasonic flowmeter according to Embodiment 2 of the present invention, the non-uniform flow suppressor 26 includes passage openings 26a each having a fine hole, and the non-uniform flow suppressor 26 is provided in the introduction portion 27 , the introduction portion 27 is provided at the upstream end of the measurement flow channel 6 . Therefore, it is possible to provide stable fluid entry into the measurement flow channel 6 regardless of the flow channel structure and/or piping structure on the upstream end of the measurement flow channel 6, so as to reduce fluid disturbance between the ultrasonic transducers 8 and 9 . Therefore, it is possible to further increase the upper limit value of the measurement and further improve the measurement accuracy. Furthermore, stable measurement can be achieved irrespective of the flow channel structure and/or piping conditions on the upstream end of the measurement flow channel 6, thereby improving the degree of freedom in the installation of the measuring device.

The non-uniform flow suppressors 26b and 26c have passage openings 26a and 26d each having a fine hole, and the non-uniform flow suppressors 26b and 26c are provided at the inlet 27 and the outlet on the upstream end of the measurement flow passage 6, respectively. The introduction portion 27 is provided at the upstream end of the measurement flow channel 6 in the portion 38 . Therefore, for a measured fluid having a fluctuating fluid with counterflow, or for a measured fluid having a fluctuating source at the downstream end, it is possible to provide a stable fluid passing through the measurement flow channel 6 so that the ultrasonic transducer 8 and Fluid disturbance between 9. Therefore, it is possible to further increase the upper limit value for this measurement, and to further improve measurement accuracy. Furthermore, stable measurement can be achieved regardless of the flow channel structure, piping conditions, and/or source of fluctuation, upstream or downstream, of the measurement flow channel 6, thereby further improving the degree of freedom in installation of the measurement device.

The cross-sectional area of the introduction portion 27 or the outlet portion 38 may be set larger than that of the measurement flow channel 6 . Therefore, it is possible to increase the installation cross-sectional area of the non-uniform flow suppressor 26 in order to reduce the pressure loss due to the non-uniform flow suppressor 26, thereby avoiding increasing the pressure loss. In addition, the cross-sectional area of the introduction part 27 or the outlet part 38 can be increased, thereby facilitating the connection of the measuring device without changing the shape of the introduction part or the outlet part, even when the flow channel or pipe structure on the upstream or downstream end when its shape is changed. Thus, a measuring device with increased degrees of freedom in its assembly can be realized.

The pore size of the passage opening of the non-uniform flow suppressor 26 is smaller than the pore size of the passage opening provided in the second flow suppressor 16 . Therefore, even when the upstream or downstream connection port is provided with a positional shift, the fluid can still flow in the measurement flow channel, thereby allowing for measurement with increased measurement accuracy. Furthermore, even when the fluid to be measured fluctuates, it is possible to provide fluid into the measurement flow channel, since the channel opening has a small aperture size, fluctuations in the fluid are reduced, thereby improving measurement accuracy even for fluctuating fluids. Furthermore, due to the small aperture size of the channel opening of the non-uniform flow suppressor, the amount of dirt and/or dust entering the measuring device can be reduced, thereby increasing the reliability of the measurement operation along the measuring flow channel.

The case where the bent pipe portions 17 and 18 are bent in the width W direction of the measurement flow channel 6 has been described in this embodiment. However, it should be understood that the curved pipe portions 17 and 18 can also be bent in the direction of the height H of the measurement flow channel 6 or any other direction, and the curved pipe portions 17 and 18 can be bent at different angles.

(Example 3)

Fig. 13 is a sectional view illustrating the structure of an ultrasonic flowmeter according to Embodiment 3 of the present invention. In FIG. 13, the same components and functions as those of the embodiment shown in FIGS. 1 to 12 have the same reference numerals and will not be described in detail again, and the components different from the above-mentioned embodiments will be collectively described below.

Reference numeral 39 is a first fluid suppressor for reducing the measured fluid flowing into the aperture 11 regardless of whether the measured fluid flows forward or backward along the measurement flow path 6 . The first flow suppressor 39 includes a deflector 40 a disposed near the upstream end of the bore 11 and a deflector 40 b disposed near the downstream end of the bore 11 . Reference numeral 41 is a second fluid suppressor which is provided on the downstream end of the ultrasonic wave propagation path 13 . The second fluid suppressor 41 includes a direction adjusting part 41a for the flow direction of the measured fluid and a fluctuation suppressing part 41b for making the flow velocity distribution uniform or reducing the fluctuation of the fluid. The aforementioned first fluid suppressor 15 includes a hole sealing member 21 having an ultrasonic transmission hole 22 provided for the downstream hole 12 . The second fluid suppressor 16 includes a direction regulating member 16 a and a fluctuation suppressing member 16 b, which are provided at the upstream end of the ultrasonic propagation path 13 .

The state of the fluid in the measurement flow channel of the ultrasonic flowmeter and its measurement operation will be described below. First, when the fluid to be measured flows forward and passes through the measurement flow channel 6, even if the non-uniform fluid or fluctuating fluid enters the measurement flow channel 6, the second fluid suppressor 16 or the first fluid suppressor 39 or 15 (such as Example 1) prevents such fluid from flowing into holes 11 and 12. Therefore, the fluid is stabilized in the ultrasonic propagation channel 13, so that the measurement accuracy and/or the upper limit value for the measurement can be improved.

Secondly, when the fluctuation causes momentary reverse flow or changes the direction of the fluid, or the reverse flow of the fluid is caused by wrong pipe connection, the reversed fluid may enter the measurement flow channel 6 . Even if this is the case, the first flow inhibitor 15 or 39 or the second flow inhibitor 41 acts on such reverse flow as on the forward flow to prevent this flow from entering the bores 11 and 12 . Therefore, even when the fluctuating fluid causes a momentary reverse flow, it is possible to reduce the flow of the measured fluid into the hole, as with the forward fluid, and significantly reduce the fluid disturbance between the ultrasonic transducers 8 and 9, thereby improving the measurement Accuracy and upper limit for flow measurement. Also, even for reverse flow, it is possible to realize measurement with increased accuracy, and to increase the degree of freedom of installation, thereby improving convenience.

It has been described above that the first flow suppressor 39 comprises protrusions of the deflectors 40a and 40b which are arranged along a surface in which the perforation 11 is open and The upstream end near the hole 11 and the downstream end near the hole 11, respectively. However, it should be understood that the protrusions may be provided at positions surrounding the periphery of the apertures 11 and/or 12 (not shown). Also, by employing the hole sealing member described above with reference to FIG. 2 or FIG. 5, the first fluid suppressor 39 can be provided so that measurement accuracy and convenience can be improved even for strong reverse flow.

Figure 14 Another embodiment of the first fluid suppressor. The case described below is where the first flow inhibitor is provided for the downstream bore 12 . Reference numeral 23 is a flow deflector disposed near the upstream end of the hole 12, including the hole sealing member 21, and reference numeral 42 is a flow deflector disposed near the downstream end of the hole 12. Each deflector 23 and 42 is arranged in the structure of a plate or a vane and adjusts the direction of fluid flow so that the measured fluid does not flow into the hole 12 . Therefore, in this embodiment, the first flow suppressor comprises the aperture sealing member 21 and the deflectors 23 and 42, which are arranged upstream or downstream of the aperture 11 and/or aperture 12, respectively.

Here, for the fluid flowing forward and passing through the measurement flow channel 6 , the flow direction thereof is adjusted by the deflector 23 provided on the upstream end of the hole 12 so as to reduce the amount of fluid flowing into the hole 12 . As for the fluid flowing in the reverse direction and passing through the measuring flow path 6, the flow direction thereof is adjusted by the deflector 42 provided on the downstream end of the orifice 12 so as to reduce the amount of fluid flowing into the orifice 12. If there is still fluid flowing into the hole 12, even if it is a small amount, it is prevented from flowing into the hole 12 by the hole sealing member 21, so as to prevent fluid disturbance (such as a vortex) in the hole 12, and thus stabilize the fluid in the ultrasonic propagation channel 13, for This is true for either forward or reverse flowing fluid, further improving measurement accuracy.

Since the amount of fluid flowing to the hole sealing part 21 can be reduced by the deflectors 23 and 42, even when the measured fluid contains fine particles of foreign matter (such as dust), the adhesion of foreign matter on the hole sealing part 21 can be reduced. . Therefore, the selection of the size of the hole sealing member 21 is mainly in consideration of the ultrasonic transmission capability, thereby improving the freedom of selection or setting therein. Moreover, the ultrasonic transmission capability can be further improved to increase sensitivity, reduce power loss or improve accuracy. The aperture sealing member 21 and deflectors 23 and 42 may also be provided for the upstream aperture 11 as for the downstream aperture 12 in order to provide a similar effect for the aperture 11 . Also, the measurement accuracy for the reverse fluid can be further improved, and thus the transmission capability of ultrasonic waves can be increased to increase sensitivity and reduce power consumption or improve measurement accuracy.

As described above, with the ultrasonic flowmeter according to Embodiment 3 of the present invention, even when the fluid fluctuates and causes momentary reverse flow, it is possible to reduce the flow of the measured fluid into the orifice, as in the case of forward fluid, and Significantly reduce fluid disturbance between ultrasonic transducers, thereby improving measurement accuracy and the upper limit of flow measurement. Also, even for reverse flow, it is possible to achieve higher-accuracy measurement and increase the degree of freedom of installation, thereby improving convenience.

Flow deflectors are provided at the upstream and downstream ends of the bore. Therefore, it is possible to further improve measurement accuracy, suppress fluid flow into the aperture, and prevent foreign matter from entering the aperture, both for forward flow and reverse flow along the measurement flow path. Therefore, even for fluctuating fluid with reverse flow, stable measurement accuracy can be maintained for a long time, improving durability and reliability.

In this embodiment, the case where the bent pipe portions 17 and 18 are bent in the width W direction of the measurement flow path 6 is described. However, it should be understood that the bends 17 and 18 may be bent in the direction of the height H of the measurement flow channel 6 or in any other direction, and the bends 17 and 18 may be bent at different angles.

(Example 4)

Fig. 15 is a sectional view illustrating the structure of an ultrasonic flowmeter according to Embodiment 4 of the present invention. In FIG. 15 , the same components and functions as those of the embodiment shown in FIGS. 1 to 14 have the same reference numerals and will not be described in detail again, and the components different from the above-mentioned embodiments will be collectively described below.

Reference numeral 43 is a propagation path flow regulator provided on the upstream end of the ultrasonic wave propagation path 13 . The propagating channel flow regulator 43 is arranged at a position substantially parallel to the ultrasonic propagating channel 13 and slightly spaced from the ultrasonic propagating channel 13 so as not to interfere with the propagation of the ultrasonic waves. The ultrasonic propagating channel 13 extends obliquely through the measurement flow Channel 6.

FIG. 16 illustrates the propagation channel flow regulator 43 , seen in the direction of the flow through the measurement flow channel 6 . A propagation channel flow regulator 43 is provided in the measurement flow channel 6, which has a circular cross section. Reference numeral 13a is an ultrasonic propagation path as shown in the cross-sectional view of the measurement flow path 6 taken in a direction perpendicular to the plane of FIG. 15 (height direction of the measurement flow path 6). The width of the propagation channel flow regulator 43 along the height direction is larger than that of the ultrasonic propagation channel 13a along the height direction indicated by the two-dot chain line, and is provided with many regulating parts 44 exposed to the fluid.

The operation of this ultrasonic flowmeter will be described below. The fluid to be measured enters the measurement flow channel 6 with non-uniform fluid or fluid fluctuation due to the increase or decrease of the cross-sectional area in the fluid channel, or due to passing through the elbow portion 17. A control valve (not shown) on the upstream end of the flow channel 6 is provided. Then, the turbulence of the fluid is facilitated (facilitated) by the regulating part 44 of the propagation channel flow regulator 43, which is directly arranged upstream of the ultrasonic propagation channel 13, so as to extend all routes from the upstream ultrasonic transducer 8 to the vicinity of the downstream ultrasonic transducer 9, therefore, fluid turbulence is also promoted in the entire area through the ultrasonic propagation channel 13. In this way, fluctuations in fluid conditions are reduced in the ultrasonic propagation channel 13 from the upstream end to the downstream end, so as to facilitate the measurement of the average flow velocity in the ultrasonic propagation channel 13 . Especially when the flow velocity is small (when the flow rate is small) and thus the fluid flows into the measurement flow channel 6 as a laminar flow, the propagation channel flow regulator 43 in the ultrasonic propagation channel 13 promotes fluid turbulence. Therefore, the difference between this fluid disturbance and the fluid disturbance caused in the ultrasonic propagation channel 13 when the flow velocity is large (when the flow rate is large) is small, and the fluid flows into the measurement flow channel 6 as the disturbed fluid. Therefore, it is possible to stably disturb the fluid in the ultrasonic propagation path 13 over a wide flow rate range from a small flow rate to a large flow rate. Also, the disposition position of the propagation passage flow regulator 43 is obliquely across the measurement flow passage 6, and therefore, compared with the length obtained when the propagation passage flow regulator 43 is disposed in a position extending and perpendicular to the measurement flow passage 6, The propagation channel flow regulator 43 in the measurement flow channel 6 can have a greater length. Accordingly, it is possible to provide a propagation channel flow conditioner 43 with a larger aperture ratio, and the resulting measurement device has reduced pressure loss.

With the measurement flow path 6 of this structure, as described above, the flow velocity V is obtained from the ultrasonic propagation times T1 and T2, and the flow rate is obtained from the cross-sectional area S of the measurement flow path 6 and the correction coefficient K. The correction coefficient K basically changes in the transition region, where the transition of the flow region is from the laminar flow region to the disturbed flow region. As shown in FIG. 17 , no propagation channel flow regulator 43 extends along the ultrasonic propagation channel 13 . Therefore, when an error of ΔQm occurs in the measured flow rate, for example, the correction coefficient K is substantially changed by ΔK1, resulting in an increase in the flow rate measurement error. This error can occur due to fluctuations in fluid conditions due to changes in Reynolds number due to changes in flow viscosity due to changes in fluid temperature or fluid composition change in ratio. This error needs to be taken into account especially when measuring the flow rate of a fluid (such as city gas or liquefied petroleum gas LPG), and the gas composition in the fluid changes due to seasonal or regional changes.

However, when the propagation path flow regulator 43 is provided along the ultrasonic wave propagation path 13, as in the present embodiment, the correction coefficient K in the laminar flow region where the flow velocity is small and the correction coefficient in the turbulent flow region can be reduced. The difference between them, as shown in FIG. 18 , is because the fluid can also be disturbed from the upstream end to the downstream end in the ultrasonic propagation channel 13 . Also, the change in the correction factor is smaller in the transition region where the flow transitions from laminar to disturbed flow. Therefore, the correction factor is averaged. Therefore, even when an error ΔQm occurs in the measured flow rate, the variation of the correction coefficient can be sufficiently small, such as ΔK2 (K2<K1), thereby facilitating improvement of measurement accuracy. This is an advantage when there is a change in temperature or a change in the composition of the fluid. Therefore, measurement accuracy can be further improved, especially when measuring the flow rate of gas (city gas or liquefied petroleum gas), such changes in composition and changes in temperature are likely to occur.

In the example described above, the length of the propagation channel flow regulator 43 from the inlet end 43 a to the outlet end 43 b is substantially constant across the width W direction of the measurement flow channel 6 . However, as in another embodiment of the propagation path flow conditioner 43 shown in FIG. 19, only the outlet end 43b closer to the ultrasonic propagation path 13 can extend along the ultrasonic propagation path 13, while the inlet end 43a does not extend along the ultrasonic propagation path 13 extensions. Disturbance will also be promoted in the ultrasonic propagation channel 13 from the upstream end to the downstream end. Therefore, it should be understood that the length from the inlet end 43a to the outlet end 43b may vary depending on the position along the width direction. Moreover, although the propagation channel flow regulator 43 is only extended on a part of the circular cross-section of the measurement flow channel 6 corresponding to the ultrasonic wave propagation channel 13, it should be understood that the propagation channel flow regulator 43 can be selected to be arranged by the The height H of the cross section is extended in order to facilitate the stability of the correction factor K. Moreover, although the outlet end 43b of the propagation path flow regulator 43 is arranged to extend substantially parallel to the ultrasonic propagation path 13 in this embodiment, it should be understood that the propagation path flow regulator 43 is arranged in any other layout as long as It is arranged at approximately the same position relative to the width W direction of the measurement flow channel 6, from the upstream end to the downstream end of the ultrasonic wave propagation channel 13, and the propagation channel flow regulator 43 can be provided with some depressions or protrusions along the outlet end 43b. Department.

Fig. 20 illustrates the structure of an ultrasonic flowmeter, in which another embodiment of the propagation channel flow conditioner is illustrated. In FIG. 20 , the same components and functions as those of the embodiment shown in FIGS. 1 to 19 have the same reference numerals and will not be described in detail again, and the components different from the above-mentioned embodiments will be collectively described below.

Reference numeral 45 is a propagation path flow regulator, which is provided at the downstream end of the ultrasonic wave propagation path 13 . The flow regulator 45 of the downstream propagation channel is arranged substantially parallel to the ultrasonic propagation channel 13 and slightly spaced from the ultrasonic propagation channel 13 so as not to interfere with the propagation of the ultrasonic waves. Reference numeral 46 is a regulating member which is provided in the downstream propagation path flow regulator 45 and is affected by the fluid. Therefore, the ultrasonic propagation channel 13 is surrounded by the upstream propagation channel flow regulator 43 and the downstream propagation channel flow regulator 45 .

The operation of this ultrasonic flowmeter will be described below. Through the adjustment part 44 of the propagation channel flow regulator 43, the fluid disturbance is evenly promoted in the width W direction passing through the ultrasonic propagation channel 13, and the propagation channel flow regulator 43 is directly arranged on the ultrasonic wave passing through the width W direction of the measurement flow channel 6. Upstream of propagation channel 13. Moreover, the downstream propagating channel flow regulator 45 is combined with the upstream propagating channel flow regulator 43 to surround the ultrasonic propagating channel 13 so as to provide a reverse pressure to the fluid in the ultrasonic propagating channel 13 . Therefore, the fluid condition can be further made uniform and stable, and the correction coefficient can be further stabilized. Moreover, fluctuations or the like may be caused due to changes in the structure of the downstream pipe, or due to the conditions in which the measured fluid is used, and have an influence on the fluid condition in the ultrasonic wave propagation path 13, and these influences can be reduced, so stable flow measurement. Even when reverse flow occurs, it is possible to maintain a stable correction factor and improve measurement accuracy.

FIG. 21 illustrates a perspective view of the propagation channel flow regulator 47 obtained by combining the upstream propagation channel flow regulator 43 and the downstream propagation channel flow regulator 45 . Reference numeral 48 is a connection part for connecting and combining the upstream propagation path flow regulator 43 and the downstream propagation path flow regulator 45, and reference numeral 49 is an ultrasonic transmission window with an open hole so as not to interfere with Ultrasonic transmission.

The propagation channel flow regulator 47 is connected and combined by the connection part 48, so that the positional displacement of the upstream regulation part 44 and the downstream regulation part 46 relative to each other can be avoided. This makes it possible to stabilize the fluid by reducing the variation of the fluid condition in the ultrasonic propagation channel 13, so that the fluctuation of the measurement is small. Also, the structure of the propagation path flow regulator 47 can be reinforced by the connecting member 48, so that the thickness or size of each of the propagation path flow regulators 43 and 45, including the regulating members 44 and 45, can be reduced. Therefore, it is possible to make the fluid condition in the ultrasonic propagation channel 13 uniform regardless of the position across the cross section of the measurement flow channel 6 . Furthermore, by reducing the thickness or size of the adjustment members 44 and 46, the aperture area through which the measured fluid flows can be increased, so that the pressure loss in the measurement flow channel can be reduced. Also, since the propagation path flow regulators 43 and 45 are reinforced by the connection member 48, they can be used for a long time without deformation, thereby improving durability and reliability. Although it has been described above that the connection part 48 is arranged to extend at the corner of the propagation path flow conditioner 47, it should be understood that the connection part 48 can be arranged at any other suitable location for reinforcement as long as it does not hinder the ultrasonic wave. Spread.

22 is a sectional view illustrating another cross section of the measurement flow channel 6 according to Embodiment 4 along the line AA. Reference numeral 50 is a flow channel wall delimiting the measurement flow channel 6, which has a rectangular cross-section with a width W and a height H. The adjustment members 44 and 46 are disposed through this rectangular cross-section.

The measurement operation regarding the rectangular cross section will be described below. The ultrasonic propagation channel 13 extends through the width W direction of the ultrasonic propagation channel 13 , so the ratio of the measurement area can be increased relative to the height H direction of the rectangular cross section. The ratio of the measurement area in the height H direction may be constant across the width W direction from the upstream end to the downstream end. Therefore, high-precision measurement of the average flow velocity of the fluid in the ultrasonic propagation channel 13 can be realized. For the fluid in the ultrasonic propagation channel 13, the fluid disturbance is uniformly promoted by the propagation channel flow regulators 43 and 45 and the regulating parts 44 and 46 from the upstream end to the downstream end in a wide flow range, so that the average can be measured with high precision. flow rate. Therefore, it is not necessary to increase the aspect ratio (W/H) of the rectangular cross-section to increase the measurement accuracy in order to increase the flatness therein to generate a stable two-dimensional flow in the measurement flow channel 6 . The upper surface and the lower surface, which jointly define the height H of the cross-section, reflect the ultrasonic waves. In order to reduce the influence of the reflected ultrasonic waves, the height H can be determined. Therefore, the specifications of the cross-section can be freely set according to the height H of the flow channel, so as to reduce the interference of reflected waves, and thus help to increase the sensitivity of ultrasonic transmission or reception. Also, measurement accuracy can be improved by reducing variations in correction coefficients.

In addition, a rectangular cross-section with less smoothness and an aspect ratio of less than 2 can be used in order to reduce the length of the cross-section contacting the measured fluid, thereby reducing the pressure loss in the measurement flow channel. It should be understood that a rectangular cross-section as used herein also includes a substantially rectangular shape in which there is a rounded portion (corner R) in each corner of the rectangular cross-section, in order to ensure that a manufacturing device (e.g., when a flow channel wall 7 is the durability of the metal mold used when forming by die-casting.

FIG. 23 illustrates the distance between the propagation path flow regulator 43 or 45 and the ultrasonic wave propagation path 13 in this embodiment. The distance between the upstream propagation path flow regulator 43 and the ultrasonic propagation path 13 is Gu, and the distance between the downstream propagation path flow regulator 45 and the ultrasonic propagation path 13 is Gd.

The distance between the propagation path flow regulator 43 or 45 and the ultrasonic propagation path 13 is optimized so that the correction coefficient for the measured value is stabilized in a wide flow range for various measured fluids, thereby in the ultrasonic propagation path 13 from Disturbs fluid distribution evenly from upstream to downstream. For example, when the Reynolds number is small, the distance Gu and (or) Gd can be reduced, and when the Reynolds number is large, the distance Gu and (or) Gd can be increased. The Reynolds number is proportional to the inverse of the flow viscosity. Therefore, for a fluid with a low viscosity, the distance Gu and (or) Gd should be increased, and for a fluid with a high viscosity, the distance Gu and (or) Gd should be decreased. For example, the flow viscosity of propane gas is 4.5mm2/s (300°K), and the flow viscosity of methane gas is 17.1mm2/s (300°K). Therefore, the distance Gu and (or) Gd should be increased for propane gas, and the distance Gu and (or) Gd should be decreased for methane gas. In this case, the propagation path flow regulator 43 or 45 should be arranged at a position as far away from the ultrasonic propagation path 13 as possible, so as to reduce the ultrasonic wave propagation path 13 and be transmitted by the propagation path flow regulator 43 or 45 The amount of reflected ultrasound that affects the flow rate measurement. However, this distance should be optimized in order to disturb the flow of the fluid evenly from the upstream end to the downstream end of the ultrasonic wave propagation channel 13 . It should be understood that the distance Gu and the distance Gd do not have to have the same value, but can be set to different values, according to the shape and (or) aperture size of the regulating member 44 of the propagation channel flow regulator 43, and the communication channel flow. The difference between the shape and/or aperture size of the adjustment member 46 of the adjuster 45 changes the relationship between the distance Gu and the distance Gd. It should be understood that the relationship between the distance and viscosity may be different than that described above when the shape and/or aperture size of the adjustment members 44 and 46 are changed depending on the type of fluid.

Therefore, it is possible to realize high-precision measurement for different fluids only by changing the flow regulator of the propagation path without changing the shape and size of the measurement flow path 6, thereby improving convenience for users. Furthermore, a low-cost measuring device can be provided by employing various general-purpose components for different situations.

Figure 24 is a perspective view illustrating another embodiment of a propagation channel flow regulator. Reference numeral 51 is a regulation part of the propagation channel flow regulator 43 . The regulating member 51 is constituted by a mesh member, such as a wire mesh or a fabric having a small thickness in the flow direction. A similar part (not shown) such as the regulating part 51 may also be provided in the propagation channel flow regulator 45 . It should be understood that the mesh member can be used alone to form the flow regulator of the transmission channel, and the outer frame 44a of the flow regulator of the transmission channel is not required.

Since the adjustment member 51 is made of a mesh member having a smaller thickness in the flow direction, the size of the propagation path flow regulator 43 or 45 in the flow direction can be reduced so that it can be installed in a small space, thereby reducing Small measure the size of the flow channel. For the mesh part covering the ultrasonic propagation channel 13, the material that is not easy to reflect ultrasonic waves is used, and the mesh part with a large aperture ratio is used in combination, which has the advantage of reducing the ultrasonic reflection by the propagation channel flow regulator 43 or 45, Thereby reducing the impact of reflected waves on the interference of measurement accuracy, thus realizing high-precision measurement.

Figure 25 is a perspective view illustrating another embodiment of a propagation channel flow regulator. Reference numeral 52 is a regulation part of the propagation channel flow regulator 43 . The adjustment member 52 includes a mesh member 53 having a plurality of wall surfaces 52a extending in the flow direction. Similar components such as the regulating member 52 may also be provided in the propagation channel flow regulator 45 (not shown).

Since the wall surface 52a extends in the flow direction, the direction of the fluid flowing through the flow regulator 43 of the propagation channel can be adjusted. Especially by reducing the fluid flowing into holes 11 and 12, the generation of eddy currents can be reduced. The holes 11 and 12 are directly arranged in front of the ultrasonic transducers 8 and 9, thereby reducing the attenuation of ultrasonic waves caused by eddy currents, so that the measurement can be achieved Create conditions for a larger flow range. Moreover, each wall surface 52a can be oriented in one direction, so that the flow velocity distribution in the ultrasonic propagation channel 13 is more balanced, so the flow velocity distribution in the ultrasonic propagation channel 13 can be further balanced, thereby improving measurement accuracy.

Fig. 26 is a front view of another embodiment of a propagation channel flow conditioner as viewed in the direction of flow. Reference numeral 54 denotes an adjustment member provided in the propagation channel flow regulator 43, wherein, according to the position along the cross-section of the measurement flow channel 6, the spacing between two adjacent adjustment members can be changed so as to change the distance between each through hole 55. the cross-sectional area of . Here, the position of the through hole 55a is along the periphery of the cross section of the propagation path flow conditioner 43, and its cross sectional area can be set larger than that of the through hole 55b in the middle portion of the propagation path flow conditioner 43. In particular, the cross-sectional area of the through hole 55 increases toward the direction of the corresponding end of the propagation channel flow conditioner 43 and in the width W direction or the height H direction. Similar components such as the regulating component 54 may also be provided in the propagation channel flow regulator 45 (not shown).

The operation will be described below. When the propagation channel flow regulator 43 is not provided, it is difficult to obtain a uniform flow velocity distribution, because the flow velocity of the fluid flowing along the wall of the measurement flow channel 6 is reduced due to the viscosity of the fluid, and the fluid flowing through the middle of the measurement flow channel 6 The fluid has a greater flow velocity. However, in this example, the propagation path flow regulator 43 is provided while the cross-sectional area of the through hole 55 is reduced in the middle of the cross-section of the measurement flow path 6 so that the flow velocity is reduced. The cross-sectional area of the through hole 55 is enlarged along the periphery so that the passage resistance thereof is smaller than that of the center, thereby suppressing a decrease in flow velocity. Therefore, the flow velocity distribution in the ultrasonic propagation channel 13 is uniform. Therefore, in the ultrasonic propagation path 13 that extends obliquely through the measurement flow path 6, the flow velocity is uniform from the upstream end to the downstream end, so the average flow velocity value measured in the ultrasonic propagation path 13 can be compared with that passing through the measurement flow path. The average flow velocity value measured by the cross-section of 6 is fully consistent from the laminar flow range to the disturbed flow range in a wide flow range, thereby stabilizing the change of the flow coefficient and improving the measurement accuracy.

As described above, in the ultrasonic flowmeter according to Embodiment 4, the propagation path flow regulator 43 is provided immediately upstream of the ultrasonic propagation path 13, and extends along the entire area of the ultrasonic propagation path 13 from its upstream end to its downstream end, Disturbance of the fluid passing through the entire area of the ultrasonic propagation channel 13 is thereby facilitated. Therefore, the characteristic of the correction coefficient due to flow rate variation can be stabilized over the entire flow rate measurement range, thereby improving measurement accuracy. Measurement accuracy can be maintained even when the physical characteristic values of the fluid change, thereby improving practicality and convenience. Moreover, through the oblique arrangement of the propagation channel flow regulator 43 passing through the measurement flow channel 6, its aperture ratio can be increased, thereby reducing the pressure loss of the measurement device. Moreover, through the oblique arrangement of the propagation channel flow regulator 43 through the measurement flow channel 6 , it can be ensured that the setting position of the regulating member 44 can pass through a larger area. Therefore, the pressure loss may not be increased to reduce the distance between adjacent adjustment components 44 and increase the number of adjustment components 44 to enhance the flow disturbance promotion effect.

Therefore, the ultrasonic propagation path 13 is surrounded by the upstream and downstream propagation path flow regulators 43 and 45, so that the disturbance condition from the upstream end to the downstream end of the ultrasonic propagation path 13 can be made uniform, thereby further stabilizing the correction coefficient and further improving the measurement accuracy . Furthermore, the influence of the flow conditions along the measurement flow channel 6 on the downstream end is reduced by the downstream propagation channel flow regulator 45 . Therefore, stable measurement can be achieved regardless of the piping condition at the downstream end of the measurement flow channel 6, thereby improving the degree of freedom in installation of the measurement device. Also, the same effect is obtained for forward flow and reverse flow along the measurement flow path, so even for fluctuating flow or reverse flow, the correction coefficient can be stabilized, thereby improving measurement accuracy.

The upstream and downstream propagation channel flow regulators 43 and 45 are combined. Therefore, a deviation in the distance between the flow regulators of the propagation channel, or a positional deviation between the upstream regulating member and the downstream regulating member can be prevented and stabilized, so that the error of the measuring device is reduced. Also, the connection member reinforces the propagation path flow regulator, so that the adjustment member can be reduced in size and thickness. Therefore, it is possible to make the flow condition in the ultrasonic propagation channel uniform, or reduce the pressure loss in the measurement flow channel.

By changing only the distance of the propagation path flow regulator from the ultrasonic wave propagation path 13, the measurement flow path can be commonly used regardless of the type of fluid to be measured, thereby improving convenience. Also, stable measurement accuracy can be maintained regardless of the type of fluid to be measured. In addition, since the measurement flow path can be commonly used, cost can be reduced.

In one embodiment, the adjustment member may be configured as a mesh member. Therefore, it is possible to reduce the installation space of the propagation channel flow regulator with respect to the flow direction, thereby reducing the size of the measurement flow channel.

In one embodiment, the adjusting part can be configured as a grid part structure, the wall surface of which extends along the flow direction to adjust the flow direction, so as to further make the flow velocity distribution in the ultrasonic propagation channel uniform, and thus improve the measurement accuracy .

Depending on the position along the cross-section of the measurement flow channel, the distance between two adjacent adjustment elements can be varied. Thus, depending on the position along the cross-section of the measurement flow channel, the size of each adjustment member can be optimized while maintaining the reduced length of the adjustment member in the flow direction. Therefore, the flow velocity distribution in the ultrasonic propagation channel can be further uniformed, and the length of the adjustment member along the flow direction can be reduced. Due to the uniform flow velocity distribution, the pressure loss can be reduced and the measurement accuracy can be improved at the same time.

By adopting a rectangular cross-section for the measurement flow channel, the measurement area relative to the total measurement cross-sectional area can be increased, thereby creating conditions for the measurement from the upstream end to the downstream end of the ultrasonic propagation channel under the same conditions, thus facilitating the average of the fluid Flow velocity is measured with high precision.

By adopting a rectangular cross-section for the propagation channel flow regulator provided along the ultrasonic wave propagation channel and for the measurement flow channel, it is not necessary to increase the aspect ratio of the cross-section to generate a two-dimensional flow, which can be freely adjusted according to the height of the flow channel The specifications of the cross-section are set to reduce the interference of reflected waves, thereby creating conditions for increasing the sensitivity of ultrasonic transmission/reception. Furthermore, the loss of pressure in the measuring flow channel can be reduced by adjusting the measuring cross-section so as to reduce the length of the contacting fluid along the measuring cross-section without making the measuring cross-section too smooth.

It has been described in this embodiment that the bent pipe portions 17 and 18 are bent in the width W direction of the measurement flow channel 6 . However, it should be understood that the bends 17 and 18 may also be bent in the direction of the height H of the measurement flow channel 6 or in any other direction, and the bends 17 and 18 may be bent at different angles.

(Example 5)

Fig. 27 is a cross-sectional view showing the structure of an ultrasonic flowmeter according to Embodiment 5 of the present invention. In FIG. 27, the same elements and functional parts as in the embodiment shown in FIGS. 1-26 have the same reference numerals and will not be described in detail below. components in the above embodiments.

Reference numeral 56 is an influent suppressor for reducing the inflow of the fluid to be measured into the holes 11 and 22 . The fluid suppressor 56 is disposed at the downstream end (downstream side) of the above-mentioned propagation channel flow regulator 43, and the propagation channel flow regulator 43 is disposed at the upstream end of the ultrasonic propagation channel 13. The fluid suppressor 56 includes a first fluid suppressor 57 formed of a hole sealing member 21 having a plurality of ultrasonic transmission holes 22 through which ultrasonic waves can be transmitted, as shown in the enlarged schematic view of FIG. 28 . The hole sealing member 21 extends through the ultrasonic propagation path 13 and is coplanar with the measurement flow path surface 6 a of the holes 11 and 12 so as to reduce the amount of fluid flowing into the holes 11 and 12 .

Figure 29 shows another embodiment of the fluid suppressor. The first flow inhibitor 58 includes a deflector 58a and a guide surface 58b. A deflector 58a is provided protruding from the flow channel wall 7 on the nearest upstream end of the upstream bore 11 . The guide surface 58b has a smoothly rising height and is located at the upstream end of the deflector 58a. The first fluid suppressor 58 deflects the fluid flowing close to the measurement flow path surface 6 a from the wall surface so that the fluid does not enter the hole 11 . When the distance between the propagation channel flow regulator and the ultrasonic propagation channel is small, the deflector 58a, the guide surface 58b and the propagation channel flow regulator 43 may be integrally formed together to provide a second fluid suppressor.

In FIG. 30, reference numeral 60 is a second fluid suppressor obtained by providing a fluid suppressing member 60b with a deflector 60a on the side of the propagation channel flow regulator 59 close to the measurement flow channel surface 6a. . Thus, the propagation channel flow regulator 59 and the second fluid suppressor 60 are integrated.

The state in which the fluid to be measured flows through the ultrasonic flowmeter will be described below. First, the measured fluid enters the measurement flow channel 6 with non-uniform fluid or fluid fluctuations provided by a control valve (not shown) provided at the upstream end of the measurement flow channel 6. caused by the rise/fall of the cross-sectional area, and/or by passing through the elbow 17 . Then, the disturbance of the fluid is facilitated by the regulation member 44 of the propagation channel flow regulator 43 arranged next to the ultrasonic propagation channel 13 . Propagation channel flow conditioner 43 is arranged in the immediate upstream of ultrasonic transmission channel 13, so as to extend omnidirectionally from the vicinity of upstream ultrasonic transducer 8 to the vicinity of downstream ultrasonic transducer 9, thus making it easy to make the fluid disturbance in It becomes equalized across the entire area of the ultrasonic propagation channel 13 . In this way, the variation of fluid conditions on the ultrasonic propagation channel 13 from the upstream end to the downstream end is reduced, so as to facilitate the measurement of the average flow velocity on the ultrasonic propagation channel 13 . In particular, when the flow velocity is small (low flow rate), and thus the fluid flows into the measurement flow channel 6 as a laminar flow, the disturbance of the fluid in the ultrasonic propagation channel 13 is facilitated by the propagation channel flow regulator 43 . Then, when the flow velocity is large (the flow rate is large), and thus the fluid flows into the measurement flow channel 6 as a disturbed flow, the difference between the fluid disturbance and the fluid disturbance causing the ultrasonic propagation channel 13 is small. Thus, it is possible to stably disturb the fluid in the ultrasonic propagation path 13 over a wide range from a small flow rate to a large flow rate. Furthermore, a propagation channel flow regulator 43 is provided extending obliquely through the measurement flow channel 6 . Thus, the propagation channel flow regulator 43 can have a length within the measurement flow channel 6 that is longer than that obtained when the propagation channel flow regulator 43 is arranged to extend orthogonally along the measurement flow channel 6 . Thus, it is possible to provide a large aperture ratio to the propagation channel flow regulator 43 and realize a measurement device with reduced pressure loss.

The flow in the vicinity of the perforation will be described below. Firstly, when only the first flow inhibitor 57 or 58 provided for the downstream eyelet 12 is used as a flow inhibitor, the inflow of the fluid into the downstream eyelet can be effectively reduced because the downstream eyelet extends at an acute angle with respect to the direction of the flow, Therefore, a strong vortex tends to appear around the hole to effectively reduce the fluid disturbance between the ultrasonic transducers, thereby increasing the upper limit of flow measurement. In particular, when the hole sealing member 21 is the first flow suppressor 57, it is possible to further increase the flow suppression effect and reduce the flow rate in the hole. Furthermore, compared with the case where the aperture sealing member 21 is provided for both apertures 11 and 12, the amount of attenuation of ultrasonic waves can be reduced, whereby the drive input to the ultrasonic transducer and the power consumption can be reduced.

Then, when the fluid suppressor is the first fluid suppressor provided for the upstream and downstream perforations 11 and 12, the disturbance in the perforations, which accounts for the main part of the total fluid disturbance in the ultrasonic propagation path, can be effectively reduced. Part, which may improve the measurement accuracy and the upper limit of the flow measurement. In particular, when the hole sealing member 21 is the first fluid suppressor 57, it can effectively reduce the disturbance of the fluid flowing forward or backward in the measurement flow channel. It will be appreciated that when the upstream bore 11 is provided with the first fluid suppressor 58 comprising the deflector 58a and the downstream bore 12 is provided with the first fluid suppressor 57 comprising the bore sealing member 21, it is possible to further reduce the distance between the ultrasonic transducers. Fluid disturbances and reduce the amount of attenuation of the ultrasonic waves, thereby reducing power consumption for the ultrasonic transducers.

Furthermore, when the fluid suppressor is a second fluid suppressor obtained by providing a fluid suppressing member to the propagation channel flow regulator, it is possible to suppress the flow rate flowing into the orifice. In addition, by combining a propagation channel flow regulator with a fluid suppressor, variations in the suppression of fluid flow into the aperture can be reduced, thereby increasing reliability. Furthermore, a small ultrasonic propagation channel can be provided, thereby reducing the size of the measurement flow channel.

Then, the ultrasonic waves are transmitted and received between the ultrasonic transducers 8 and 9 along the ultrasonic propagation path 13 in which the fluid is stabilized. Thus, it is possible to realize high-precision measurement of flow velocity and reduce attenuation of ultrasonic waves due to changes in flow rate, thereby increasing the upper limit value for flow rate measurement. Without the first flow suppressor 57 or 58 or the second flow suppressor 60, the strong flow in the measurement flow channel 6 could flow into the aperture 12, thereby creating a strong vortex, because the downstream aperture 12 is along with the measurement The flow channel 6 extends in the direction of an acute angle, therefore, a decrease in the accuracy of the measurement of the flow rate may be caused due to fluctuations in the flow rate in the part of the fluid, and/or the upper limit of the measurement may be caused by a vortex Ultrasound attenuation is reduced, also for the upstream bore 11 , in the absence of the first flow suppressor 57 or 58 or the second flow suppressor 60 , an inflow of fluid would occur. However, this flow rate is small because the orifice 11 extends in a direction at an acute angle to the measurement flow channel 6 , where the intensity of said eddies is less than that generated around the downstream aperture 12 . It will be appreciated that it is possible to further stabilize the flow by providing a first flow inhibitor 57 or 58 or a second flow inhibitor for the upstream bore 11 .

The correction coefficient K used when obtaining the flow rate based on the ultrasonic propagation times T1 and T2 will be described below. The propagating channel flow conditioner 43 is arranged at the position close to the upstream of the ultrasonic propagating channel 13, and extends from the upstream end to the downstream end thereof along the entire area of the ultrasonic propagating channel 13, thus facilitating the crossing of the ultrasonic propagating channel 13 Disturbance of the fluid in the entire region. Thereby, the correction coefficient K is stabilized and its variation is reduced for the change of the flow velocity in the case described above with reference to FIGS. 17 and 18 . Since the characteristics of the correction coefficient due to changes in the flow rate are stabilized, the measurement accuracy is maintained even when the physical property values of the fluid vary, thereby improving practicability and convenience. Furthermore, by significantly reducing the disturbance of the fluid between the ultrasonic transducers, the level of ultrasonic reception across the entire measurement range can be further increased, thereby further increasing the measurement accuracy. In addition, the flow rate of the fluid flowing into the holes 11 and 12 can be reduced to significantly reduce the fluid disturbance between the ultrasonic transducers, thereby increasing the upper limit of the flow rate measurement.

When the hole sealing member is a mesh member of a mesh structure inclined with respect to the horizontal direction, or when the deflectors are provided at the upstream and downstream ends of the hole, the correction coefficient can be stabilized and the measurement accuracy can be improved. In addition, the effects described in Embodiment 1 above can also be provided, thereby further improving reliability.

Figure 31 shows another embodiment of a fluid suppressor. It comprises a first fluid suppressor 57 having an aperture sealing member 21 having an ultrasonic transmission hole 22, and a second fluid suppressor 62 having a fluid suppressing member 62a arranged at the measurement The side of the propagation channel flow conditioner 61 near the flow channel surface 6a. Thus, the effect of suppressing the fluid to be measured from flowing into the hole can be further enhanced, thereby further improving measurement accuracy. Furthermore, it is possible to reduce the attachment of foreign matter such as dust adhering to the aperture sealing member by providing the deflector. Thus, the aperture sealing member can be selected mainly in consideration of the ultrasonic transmittance without much consideration of the clogging of the aperture sealing member, thereby increasing the degree of freedom of the selection. In addition, it is possible to further increase ultrasound transmittance to reduce power consumption, or to further increase sensitivity in order to realize a device with desired measurement accuracy. In addition, the second fluid suppressor 62 can be processed into a shape suitable for the flow rate or physical property value of the measured fluid as a part of the propagation channel flow regulator 61, thereby, it is easy to use the measurement flow channel universally. 6 itself. Additionally, turbulence in the bore can be reduced by the multiplied effect of the first and second suppressors, and variations in the inhibition of fluid flow into the bore can be reduced by the combination of the propagation channel flow regulator and the fluid suppressor. Thereby, the accuracy and reliability of measurement can be improved. In addition, a miniaturized ultrasonic propagation channel can be provided to reduce the size of the measurement flow channel.

Figures 32 and 33 illustrate another embodiment of a propagation channel flow regulator and fluid suppressor. The ultrasonic propagation path 13 is surrounded by an upstream propagation path flow regulator 43 and a downstream propagation path flow regulator 45 , and a fluid suppressor 56 is also provided. As shown in FIG. 33 , the propagation path flow regulators 43 and 45 are connected and joined together by a connecting member 48 . Furthermore, a fluid suppressor 56 is fixed on the ultrasonic transmission window 49 . The fluid suppressor 56 is in the shape of a net, such as the hole sealing member 21 covering the holes 11 and 12 .

In this structure, due to the reverse pressure applied by the downstream propagation path flow regulator 45, the flow rate in the ultrasonic wave propagation path 13 is equalized and stabilized. In addition, stable flow measurement can be achieved by reducing the influence on fluid conditions in ultrasonic propagation from factors such as fluctuations due to changes in the structure of downstream pipes or the usage of the measured fluid.

In addition, flow suppressors 56 are provided for the holes 11 and 12, so that the upper limit value for flow measurement can be increased.

In addition, the propagation path flow regulators 43 and 45 are connected together, which are further combined with the aperture sealing member 21 as the fluid suppressor 56 . Thereby, a positional relationship, such as the distance between these elements, is determined, whereby variations in fluid conditions in the ultrasonic wave propagation path 13 can be reduced, and stable measurement with little variation can be achieved. In addition, since not only the propagation path flow regulators 43 and 45 are combined but also the hole sealing member 21 is combined with the propagation path flow regulators 43 and 45, it is possible to further improve the mechanical properties of the propagation path flow regulators. strength. Thus, deformation can be prevented over a long period of use, thereby improving durability and reliability.

Although the position where the propagation path flow regulator 43 is installed is substantially parallel to the ultrasonic wave propagation path 13 along the width W direction of the measurement flow path 6, the propagation path flow regulator 43 may also be installed in the measurement flow regulator 43, the measurement The flow regulator 43 has a circular cross section in the height H direction as described above with reference to FIG. 16 . The same effects as those of the above-described embodiment can be expected to be obtained by installing the propagation channel fluid regulator 43 in the measurement flow channel 6 having a rectangular cross section as described above with reference to FIG. 22 . In the case where the orifice is formed to have a hole shape, or the non-uniform flow suppressor is provided at the introduction portion on the upstream end of the measurement flow passage or the outlet portion on the downstream end of the measurement flow passage, similarly , the effect described in the above embodiment can be expected to be obtained, wherein one side of the hole shape is substantially along a direction perpendicular to the direction in which the fluid passes through the measurement flow channel.

As described above, in the ultrasonic flowmeter according to Embodiment 5, the propagation path flow regulator 43 is provided immediately upstream of the ultrasonic propagation path 13 so as to extend from the upstream end to the downstream end thereof along the entire area of the ultrasonic propagation path 13 The extension, thereby, promotes the disturbance of the fluid across the entire area of the ultrasonic propagation channel 13 . Thus, the characteristic of the correction coefficient due to the change in the flow rate can be stabilized over the entire flow rate measurement range, thereby preventing an increase in error due to the correction coefficient and improving measurement accuracy. In addition, a fluid suppressor may be provided to reduce fluid flow into the bore, thereby greatly reducing fluid turbulence in the ultrasonic propagation path. Thus, it is possible to increase the ultrasonic reception level and increase the upper limit value for flow rate measurement.

The flow suppressor may be the first flow suppressor provided for the downstream bore. Therefore, the flow suppressor is used for downstream apertures around which strong vortices tend to occur because the downstream apertures extend in a direction at an acute angle with respect to the flow. Therefore, the fluid flowing into the hole can be reduced to effectively reduce the flow disturbance between the ultrasonic transducers, thereby increasing the upper limit of flow measurement.

The flow inhibitor may be a first flow inhibitor provided for the upstream bore and the downstream bore. Therefore, the disturbance in the hole accounts for the main part of the total flow disturbance in the ultrasonic propagation channel. For the downstream or reverse flow along the measurement flow channel, this disturbance can be effectively reduced, thereby improving the measurement accuracy and improving the flow measurement. limit.

The fluid suppressor may be a second fluid suppressor obtained by providing a fluid suppressing member to the propagation channel flow regulator. Thus, by combining the propagation path flow regulator and the fluid suppressor, variations in suppression of fluid flowing into the aperture can be reduced, thereby improving reliability and providing a small ultrasonic propagation path can be considered. Thereby, the size of the measurement flow channel can be reduced.

The first fluid suppressor may be an aperture sealing member having at least one ultrasonic transmission aperture. Thus, by covering the aperture with the aperture sealing member, the effect of suppressing the flow rate into the aperture can be further enhanced, thereby reducing and stabilizing the fluid in the aperture. In addition, although the transmission of ultrasonic waves can be ensured by the ultrasonic wave transmission hole, the hole sealing member is only provided for the downstream hole, in which case, the attenuation of the ultrasonic waves can be further reduced, thereby reducing the driving force for the ultrasonic transducers. input and power consumption.

The first fluid suppressor may include an aperture sealing member having an ultrasonic transmission aperture and a deflector disposed adjacent the aperture. Thus, the suppressing effect of the fluid to be measured flowing into the aperture can be further enhanced, thereby improving measurement accuracy. In addition, it is possible to reduce the adhesion of foreign matter such as dust on the hole sealing member by providing a deflector. Thus, the hole sealing member can be selected mainly in consideration of the ultrasonic transmittance without much consideration of clogging of the hole sealing member, which increases the degree of freedom of selection. In addition, it is possible to further increase ultrasound transmittance to reduce power consumption, or to further increase sensitivity in order to realize a device with desired measurement accuracy.

The fluid suppressor may comprise a first fluid suppressor provided for the bore and a second fluid suppressor obtained by providing a fluid suppressor member to the propagation channel flow regulator. Thus, turbulence in the bore can be reduced by the multiplied effect of the first and second suppressors, and variations in the suppression of fluid flow into the bore can be reduced by the combination of the propagation channel flow regulator and the fluid suppressor. Therefore, the accuracy and reliability of measurement can be improved. Furthermore, a small ultrasonic propagation channel can be provided, thereby reducing the size of the measurement flow channel.

This embodiment shows the case where the bent pipe portions 17 and 18 are bent in the width W direction of the measurement flow channel 6 . In addition, it can be understood that the curved pipe portions 17 and 18 can also choose to extend along the height H direction of the measuring flow channel 6 or any other direction, and the curved pipe portions 17 and 18 can be bent at different angles.

(Example 6)

Fig. 34 is a cross-sectional view showing a flow channel of an ultrasonic flowmeter according to Embodiment 6 of the present invention. In FIG. 34, the same elements and functional parts as in the embodiment shown in FIGS. 1-33 have the same reference numerals and will not be described in detail below. components in the above embodiments.

Reference numeral 63 denotes an isolation channel provided in each of the holes 11 and 12 . This separation channel 63 is obtained by separating each of the perforations 11 and 12 in the direction of propagation of the ultrasonic waves. As shown in FIG. 35, the isolation passage 63 has an inlet surface 65 extending along the vibrating surface 64 of the ultrasonic transducer 9 and an outlet surface 66 extending along the measurement flow passage surface 6a. The size of one side 67 of the vertical portion of the isolation channel 63 is larger than the half-wavelength λ/2 of the ultrasonic wave used for transmission/reception, and is not an integral multiple of the half-wavelength of the ultrasonic wave. The distance 68 between the separating channel 63 of the borehole 12 and the vibration surface of the ultrasonic transducer 9 is an integer multiple of the half-wavelength λ/2 of the ultrasonic waves. The thickness of each partition of the isolation channel 63 is shorter than the wavelength λ of the ultrasonic waves. Although the above description is directed to the downstream ultrasonic transducer 9 , it applies equally to the upstream ultrasonic transducer 8 .

As shown in FIG. 36, each separation channel 63 of the hole 11 provided along the measurement flow channel surface 6a is arranged to extend in line with the separation channel 63 of the corresponding one of the other hole 12, wherein the measurement flow channel surface 6a is opposite to the ultrasonic transducer 9 .

Common methods for flow measurement will be described below. As described above, the ultrasonic flowmeter obtains the flow velocity V shown in the following formula based on the difference between the reciprocal of the ultrasonic propagation time T1 and the reciprocal of the ultrasonic propagation time T2, and multiplies the flow velocity V by the cross-sectional area of the flow channel to obtain Flow velocity V is converted to flow.

Then, the fluid velocity V is obtained as shown in the following equation:

V＝[L/(2cos θ)]×[(1/T1)-(1/T2)]

Affected by the fluid, the ultrasonic propagation distance L changes according to whether there is fluid flowing into the hole. In particular, fluid may or may not enter the orifice based on flow velocity or the presence/absence of fluctuating flow, thereby changing the effective travel distance L and causing errors in the measured flow.

In the structure of the present invention, the inside of each aperture provided in the measurement flow channel is divided into several smaller parts. Swirls are then less likely to occur and the flow rate of fluid flowing into the bore may be reduced due to the isolation channel's function as a fluid suppressor. Thus, even when the fluid velocity changes or fluctuates, it is possible to maintain the effective propagation distance L constant and measure the flow rate correctly. In addition, due to ultrasonic waves propagating through the fluid under test within the isolated channel, the reduction in sensitivity may be less than would result when using bulky elements. Furthermore, due to the separation of the channels, it is possible to maintain the rectilinear characteristic of the ultrasonic wave and realize its ideal transmission/reception. Furthermore, since ultrasonic waves can enter the isolation channel at right angles and thus travel in a straight line through the channel, an ultrasonic propagation channel with no offset and little attenuation can be provided. Furthermore, because the outlet is a smooth surface relative to the surface of the measurement flow channel, there is no disturbance in the fluid in the peripheral layer along the surface of the measurement flow channel. Furthermore, since the exit surface is calibrated as a radiating surface, the ultrasonic waves can be efficiently radiated. The emitting surface of one of the pair of isolated channels is aligned with the receiving surface of the other isolated channel along the direction of travel of the ultrasonic wave, thereby reducing reflections caused by partitioned plates in the isolated channel of the opposite hole attenuation.

The side 67 of the profile of each isolation channel is longer than half a wavelength. Consequently, the viscous influence of the separating surface will be reduced, thereby making it possible to provide an isolated channel with little attenuation. In addition, the length of the side 67 can be set to be other than an integer multiple of the wavelength to suppress transverse resonance, thereby achieving efficient propagation.

The distance 68 between the ultrasonic transducer and the inlet surface of the insulating channel can be set such that the resonance occurs at half-wave. The thickness d of each partition of the isolation channel may be set shorter than the wavelength to prevent deviation of ultrasonic waves entering the partition, thereby providing efficient propagation of the ultrasonic waves and achieving desired transmission/reception.

The same effect is obtained when using isolating channels of rectangular cross-section, as shown in Figures 37, 38 and 39. When honeycomb-shaped partition channels are used as shown in FIG. 40, the honeycomb mesh can be easily fixed by being fixed in the holes. In addition, the thickness d of the partition portion may be sufficiently smaller than the wavelength of ultrasonic waves, and it is possible to separate each hole in the vertical direction and the lateral direction. In addition, ultrasonic waves propagate efficiently, thereby achieving desired transmission/reception.

One of the separating channels has its opening in the middle of the bore. Then, since there is an opening in the center of the hole, the hole is aligned with the central axis of the ultrasonic transducer, thereby effectively achieving propagation in the central region where the output of ultrasonic waves is high, thereby improving by ultrasonic transmission/reception The emission of the signal.

When a polygonal shape is adopted so that the facing faces of the isolation passage are not parallel to each other, propagation in a direction perpendicular to the traveling direction of ultrasonic waves is dispersed, so that resonance is unlikely to occur, and thus ultrasonic waves can be effectively propagated. Specifically, when a honeycomb mesh material is used for the isolation channel having an opening in its center, signal transmission may be more effective due to ultrasonic transmission/reception, which is determined by the above-mentioned resonance This is caused by the reduction of the phenomenon, the effect provided by the sufficiently small thickness d of the partition, and the efficient propagation of ultrasonic waves in the central region where the ultrasonic output is high.

In addition, as shown in Figure 41, each isolation channel may include a communication member 69 at a certain point along its length for communicating the isolation channel with an adjacent one of the isolation channels. Thus, the total area of the partition is reduced, and attenuation caused by the wall surface can be minimized, and the size of the communicating part 69 can also be larger than the wavelength of ultrasonic waves, so that the partition channels can be easily connected to each other. By alternately providing the connecting member and the partitioning portion, it is possible to obtain the effect of partitioning and the effect of reducing attenuation.

Hereinafter, another embodiment of the isolation channel will be described with reference to FIGS. 42 and 43 . FIG. 42 is a cross-sectional view showing the isolation channel 70 of the aperture 12 . The difference from the previous embodiment is that the partition portion is formed by providing a wire mesh as a mesh substance on the ultrasonic transducer in the direction perpendicular to the ultrasonic propagation direction and on the flow channel side along the flow channel wall surface. (wire mesh), whereby the channel length Lb of the isolation channel is shorter than the wavelength λ of the ultrasonic waves used for transmission/reception. FIG. 43 shows the opening 71 .

By employing a channel length shorter than the wavelength of the ultrasonic waves, each isolation channel can be used as a propagation channel with little attenuation. In addition, the hole space in each hole provided along the surface of the measurement flow path is divided into several smaller spaces, making it impossible to generate a vortex and making it possible to reduce the flow rate of the fluid flowing into the hole. Therefore, the flow rate can be measured correctly even when the flow rate changes or fluctuates. In addition, since the ultrasonic waves pass through the gas in the isolated channel, the decrease in sensitivity will be less than that which would occur when using a bulky element. Also, through the separation of the channels, it is possible to maintain the rectilinear characteristic of the ultrasonic wave and realize its desired transmission/reception.

The side 67 of the longitudinal cross-section of the separation channel is longer than this half wavelength, thus making it possible to provide a propagation channel which is less viscous to the fluid flowing along the separation surface and thus has little attenuation. In addition, efficient propagation is achieved by setting the length of the side 67 to a non-integer multiple of the wavelength to suppress resonance in the transverse direction.

Fluid turbulence in the orifice can be further reduced by using an isolated channel for the measurement flow channel provided with a fluid suppressor such as the first suppressor or the second suppressor. Thus, in addition to the above-mentioned effects, it is also possible to increase the upper limit value for measurement.

industrial application

It can be clearly seen from the above description that the ultrasonic flowmeter of the present invention provides the following effects.

The ultrasonic flowmeter of the present invention includes: a first fluid suppressor arranged in the vicinity of at least the downstream hole, which is used to reduce the inflow of the measured fluid flowing into the hole; a second fluid suppressor at the upstream end of the channel for reducing the inflow of the fluid under test into the aperture, wherein the first fluid suppressor provided for the downstream aperture comprises an aperture seal having at least one ultrasonic transmission hole part. Therefore, it is possible to stabilize the flow between the ultrasonic transducers to enhance the ultrasonic reception level and reduce the drive input to the ultrasonic transducers by enhancing the ultrasonic reception level and improving attenuation of ultrasonic waves by providing the fluid suppressor.

Alternatively, the ultrasonic flowmeter of the present invention includes a first fluid suppressor and a second fluid suppressor for reducing the flow rate of the measured fluid flowing into the hole, and the hole is used for the forward flow and reverse flow of the measured fluid, wherein, When the fluid flows in the forward direction, the first fluid suppressor provided for the aperture at the upstream end is an aperture sealing member having at least one ultrasonic transmission hole; and the second fluid suppressor is provided at the measurement flow path entry and exit ports. Thus, even when the flow rate has fluctuations and causes momentary reverse flow, it is possible to reduce the flow rate of the measured fluid flowing into the hole, as in the case of downstream flow, and remarkably reduce the disturbance of the fluid between the ultrasonic transducers, by This increases the measurement accuracy and the upper limit of the flow measurement.

Alternatively, the ultrasonic flowmeter of the present invention includes: a propagation channel regulator arranged along an ultrasonic propagation channel and having a regulating member exposed to the fluid, the ultrasonic propagation channel is located between the upstream ultrasonic transducer and the downstream ultrasonic transducer between devices. Then, the adjustment member of the propagation channel regulator disposed immediately upstream of the ultrasonic propagation channel facilitates the disturbance of the fluid across the entire area from the upstream end to the downstream end of the ultrasonic propagation channel. Therefore, in the ultrasonic propagation channel, the flow state across the entire area of the ultrasonic propagation channel is equally disturbed regardless of the flow velocity, wherein the ultrasonic propagation channel is from the area near the upstream eyelet to the area near the downstream eyelet in the width direction area, thereby preventing the increase of errors caused by correction coefficients and improving measurement accuracy. Thus, even when the Reynolds number changes due to a change in flow viscosity of the fluid, the measurement accuracy is maintained, whereby it is possible to realize a measurement device that can withstand changes in the temperature of the fluid or changes in the composition of the fluid, thereby improving the practicability of the device .

Alternatively, the ultrasonic flowmeter of the present invention includes: a propagation channel regulator arranged along an ultrasonic propagation channel and having a regulating member exposed to the flow, the ultrasonic propagation channel is located between the upstream ultrasonic transducer and the downstream ultrasonic transducer Between the devices, and a fluid suppressor, used to reduce the flow rate of the measured fluid flowing into the hole. Then, the regulation member of the propagation channel flow regulator arranged immediately upstream of the ultrasonic propagation channel facilitates disturbance of the fluid across the entire area from the upstream end to the downstream end of the ultrasonic propagation channel. Therefore, in the ultrasonic propagation channel, the fluid across the entire area of the ultrasonic propagation channel, which is from the area near the upstream eyelet to the area near the downstream eyelet in the width direction, is equally disturbed regardless of the flow velocity. area, thereby preventing an increase in error caused by the correction factor and improving measurement accuracy. In addition, it is possible to provide a measurement flow channel for the aperture, which leads to the measurement flow channel, so as to reduce the flow of fluid into the aperture, thereby significantly reducing the disturbance of the fluid between the ultrasonic transducers along the ultrasonic propagation channel, and Increase the upper limit value for flow measurement.

Alternatively, the first flow inhibitor provided for the upstream bore is a deflector. Thus, it is possible to reduce the propagation loss of the ultrasonic wave passing through the ultrasonic wave transmission hole for the upstream eyelet, thereby reducing the drive input to the ultrasonic transducer, and reducing the flow rate of fluid flowing into the upstream eyelet, thereby stabilizing the propagation along the ultrasonic wave Fluid perturbation of the channel improves the accuracy of the measurement.

Alternatively, the first fluid suppressor provided for the upstream aperture is an aperture sealing member having at least one ultrasound transmission aperture. Thus, it is possible to significantly reduce the flow rate of the fluid flowing into the upstream and downstream holes, thereby raising the upper limit value of the flow rate measurement and improving the measurement accuracy for the flow rate even accompanied by reverse flow. In addition, it is possible to realize ultrasonic transmission/reception with desired S/N characteristics by greatly reducing fluid disturbance caused by the perforation. Thereby, transmission output and drive input can be reduced, thereby reducing power consumption.

Alternatively, the aperture ratio of the aperture sealing member provided for the upstream aperture is greater than the aperture ratio of the aperture sealing member provided for the downstream aperture. Accordingly, the propagation loss of ultrasonic waves can be reduced, making it possible to increase the upper limit of flow measurement and the measurement accuracy of reverse flow, and reduce power loss by reducing the drive input to the ultrasonic transducer.

Alternatively, the propagation channel fluid regulators are provided at upstream and downstream ends relative to the ultrasonic wave propagation channel. Then, the ultrasonic propagation channel is surrounded by the upstream and downstream propagation channel flow regulators, so that it is possible to equalize the disturbance state from the upstream and downstream ends of the ultrasonic propagation channel, thereby further stabilizing the correction coefficient and further improving the measurement accuracy. Furthermore, the influence of the flow conditions on the downstream end along the measurement flow path is reduced by the downstream propagation path flow conditioner. Thus, it is possible to realize stable measurement regardless of the piping condition at the downstream end of the measuring device, so that the degree of freedom in installing the measuring device can be improved. Furthermore, the same effect can be obtained regardless of forward flow or reverse flow along the measurement flow path, so that it is possible to stabilize the correction coefficient even for fluctuating flow, thereby improving the accuracy of measurement.

Alternatively, the propagation path flow regulators disposed at upstream and downstream ends relative to the ultrasonic wave propagation path are connected together by a connector member. Thus, it is possible to prevent and stabilize the deviation of the pitch between the flow regulators of the propagation passage or the positional deviation between the upstream regulating member and the downstream regulating member, thereby obtaining a measurement device with reduced variation. Furthermore, the connecting member reinforces the propagation channel flow regulator, whereby it is possible to reduce the size and thickness of the regulating member. It is thereby possible to equalize the fluid state in the ultrasonic propagation channel or to reduce the pressure loss of the measurement flow channel.

Alternatively, the propagation channel flow regulator and the fluid suppressor provided at the upstream end and the downstream end with respect to the ultrasonic wave propagation channel are combined together. Thus, it is possible to determine the positional relationship, such as the distance between the upstream and downstream propagation path flow regulators and fluid suppressors, thereby stabilizing the fluid state. Therefore, it is possible to reduce the variation of the fluid condition in the ultrasonic wave propagation path and realize stable measurement with little variation. Through this combination, it is possible to further increase the mechanical strength of the propagation channel flow regulator, thereby preventing its deformation after long-term use, and thereby improving its durability and reliability.

Alternatively, the flow inhibitor is a first flow inhibitor provided for the downstream bore. The first flow inhibitor is then provided for a downstream aperture around which strong swirls are prone to occur, since the downstream aperture extends in a direction at an acute angle to the flow. Thus, it is possible to reduce the flow rate of the fluid flowing into the aperture so as to effectively reduce the fluid disturbance between the ultrasonic transducers, thereby increasing the upper limit value of the flow rate measurement.

Alternatively, the flow inhibitor is a first flow inhibitor provided for the upstream bore and the downstream bore. Thus, the disturbance in the aperture, which accounts for a major part of the total fluid disturbance in the ultrasonic propagation channel, can be effectively reduced, whereby it is possible to improve the measurement accuracy and the upper limit value of the flow rate measurement.

Alternatively, the fluid suppressor is a second fluid suppressor obtained by providing a propagation path flow regulator provided along the ultrasonic wave propagation path with a fluid suppressing member. Thus, by combining the propagation path flow regulator with the fluid suppressor, it is possible to reduce the suppression of the flow rate of the fluid flowing into the aperture, thereby increasing reliability and allowing a small ultrasonic propagation path to be provided. Thus, the size of the measurement flow channel can be reduced.

Alternatively, the fluid suppressor comprises a first fluid suppressor provided for the orifice and a second fluid suppressor obtained by providing a fluid suppressor member to the propagation channel flow regulator. Thus, turbulence in the bore is reduced by the multiplied effect of the first and second flow suppressors, and variations in the suppression of fluid flow into the bore are reduced by the combination of the propagation channel flow regulator and the flow suppressor. Thus, measurement accuracy and reliability can be improved. Furthermore, measurement accuracy and reliability can be increased. In addition, a small ultrasonic propagation channel can be provided, thereby reducing the size of the measurement flow channel.

Alternatively, the first fluid suppressor is an aperture sealing member having at least one ultrasonic transmission aperture. Thus, by covering the aperture with the aperture sealing member, the effect of suppressing the flow rate of the measured fluid flowing into the aperture can be further improved, thereby reducing and stabilizing the fluid in the aperture.

Alternatively, the first fluid suppressor includes an aperture sealing member having at least one ultrasonic transmission hole and a deflector disposed near the aperture portion. Thus, it is possible to further improve the suppressing effect on the flow rate of the fluid to be measured flowing into the aperture, thereby further improving measurement accuracy. In addition, it is possible to reduce the adhesion of foreign substances such as dust stuck to the aperture sealing member by providing the deflector. Thus, the aperture sealing member can be selected mainly in consideration of the ultrasonic transmittance without much consideration of clogging of the aperture sealing member, thereby increasing the degree of freedom of the selection. In addition, it is possible to further increase ultrasound transmittance to reduce power consumption, or to further increase sensitivity in order to realize a device with desired measurement accuracy.

Alternatively, the aperture ratio of the aperture sealing member provided for the upstream aperture is greater than the aperture ratio of the aperture sealing member provided for the downstream aperture. Accordingly, the propagation loss of ultrasonic waves can be reduced, so that the upper limit value for flow measurement and measurement accuracy for reverse flow can be improved, and power loss can be reduced by reducing the driving input to the ultrasonic transducer.

Alternatively, the hole sealing member is a mesh member having a mesh structure inclined with respect to the horizontal direction. Then, the mesh structure is inclined with respect to the horizontal direction, so that it is possible to facilitate the treatment of small particles, such as dust attached to the inclined mesh portion, thereby reducing the amount of such particles deposited and thus preventing the Blockage of mesh components. Thus, it is possible to secure the propagation of ultrasonic waves therein and maintain stable measurement accuracy over a relatively long period of time, thereby improving durability and reliability.

Alternatively, the deflector is positioned at both the upstream and downstream ends of the bore. Thus, it is possible to further improve the measurement accuracy, suppress the flow into the aperture, and prevent foreign substances from entering the aperture regardless of forward flow or reverse flow along the measurement flow path. Therefore, even for a fluctuating flow accompanied by reverse flow, it is possible to maintain stable measurement accuracy for a long period of time, thereby improving durability and reliability.

Alternatively, the distance between the propagation channel flow regulator and the ultrasonic propagation channel varies depending on the type of fluid to be measured. Thus, it is possible to universally use the measurement flow path regardless of the type of the fluid to be measured by changing only the propagation path flow regulator, thereby improving convenience and maintaining the flow regardless of the fluid to be measured. Stable measurement accuracy. In addition, since the measurement flow path can be commonly used, it is possible to reduce the cost.

Alternatively, the regulating part of the provided flow regulator of the transmission channel is a net-like structure. Thus, it is possible to reduce the installation space of the propagation channel flow regulator with respect to the flow direction, thereby reducing the size of the measurement flow channel.

Alternatively, the regulating member of the flow regulator of the propagation channel is a structure of a mesh member whose wall surface extends along the flow direction. The flow direction can thus be adjusted by the wall surface extending in the direction of flow, whereby the velocity distribution of the fluid in the ultrasonic wave propagation channel is further uniformed and thus the accuracy of the measurement is increased.

Alternatively, the interval between two adjacent adjustment members of the propagation channel flow regulator is changed depending on the position along the cross-section of the measurement flow channel. It is then possible to optimize the hole size according to the position along the cross-section of the measurement flow channel, while maintaining the reduced length of the adjustment member in the flow direction. Thereby, it is possible to further equalize the flow velocity distribution in the ultrasonic propagation channel, and reduce the length of the adjustment member along the flow direction, thereby reducing the pressure loss, and at the same time improving measurement accuracy due to uniform flow velocity distribution.

Alternatively, the cross-section of the measurement flow channel perpendicular to the flow direction has a rectangular shape. Thus, by adopting a rectangular cross-section, it is possible to increase the measurement area relative to the total measurement cross-sectional area, thereby allowing fluid measurement from the upstream end to the downstream end of the ultrasonic wave propagation channel under the same conditions. In addition, the two-dimensionality of the flow along the measurement flow channel can be increased, thereby allowing for high-precision measurement of the average flow velocity of the fluid. Furthermore, the two-dimensionality of the fluid flow can be further improved by providing a second fluid suppressor.

Alternatively, the shape of the cross-section of the measurement flow channel in a direction perpendicular to the fluid flow therethrough is a rectangle with an aspect ratio smaller than 2. Therefore, it is not necessary to establish a two-dimensional fluid flow by increasing the aspect ratio, and the specification of the cross section can be freely set according to the height of the flow channel, thereby creating conditions for improving the sensitivity of ultrasonic transmission/reception. Furthermore, it is possible to reduce the pressure loss in the measurement flow channel by adjusting the measurement cross-section in order to reduce the length of the measurement cross-section in contact with the fluid without excessively flattening the measurement cross-section.

Alternatively, the aperture opens into the measurement flow channel, wherein the shape has a side extending in a direction substantially perpendicular to the direction of fluid passing through the measurement flow channel. It is then possible to equally transmit/receive the ultrasonic waves with respect to the height direction of the measurement flow channel, and to shorten the hole length in the hole of the measurement flow channel in the flow direction. Thereby, it is possible to further reduce the fluid turbulence caused by the perforation, thereby further improving the measurement accuracy.

Alternatively, the introduction portion provided at the upstream end of the measurement flow passage is provided with a non-uniform flow suppressor having a passage opening with a small hole. Thus, it is possible to provide a stable fluid flowing into the measurement flow channel regardless of the shape of the flow channel or the piping structure upstream of the measurement flow channel, whereby fluid disturbance between ultrasonic transducers can be reduced. In addition, it is possible to further increase the upper limit value of the flow rate measurement and to further improve the measurement accuracy. Furthermore, it is possible to realize stable measurement regardless of the shape of the flow passage or the pipe structure upstream of the measurement flow passage, thereby increasing the degree of freedom in installation of the measurement device.

Alternatively, the introduction portion provided on the upstream end of the measurement flow passage or the outlet portion on the downstream end of the measurement flow passage are each provided with a non-uniform flow suppressor having a passage opening with a small hole. Thus, even when the measured fluid has a fluctuating flow accompanied by reverse flow or the measured fluid has a fluctuating source at the downstream end, it is possible to provide a stable fluid flowing into the measurement flow path. Thus, it is possible to reduce the fluid disturbance between the ultrasonic transducers, so as to further increase the upper limit of the flow measurement and further improve the measurement accuracy. Furthermore, it is possible to realize stable measurement regardless of the shape of the flow channel, the channel structure, or the source of fluctuation, upstream or downstream of the measurement flow channel, thereby increasing the degree of freedom in installation of the measurement device.

Alternatively, the cross-sectional area of the introduction portion or the exit portion is larger than the cross-sectional area of the measurement flow channel. Thereby, it is possible to increase the installation cross-sectional area of the non-uniform flow suppressor so as to reduce the pressure loss caused by the non-uniform flow suppressor, thereby preventing an increase in pressure loss. In addition, the cross-sectional area of the introduction part or the outlet part can be increased, thereby facilitating the installation of the measuring device without changing the introduction part even when the shape of the flow passage or the pipe structure at the upstream or downstream end is changed or the shape of the exit section. Thereby, it is possible to realize a measuring device with an increased degree of freedom of installation.

Alternatively, the pore size of the passage opening of the non-uniform flow suppressor is smaller than the pore size of the passage opening provided in the second flow suppressor. Thus, even when the arrangement of the upstream or downstream connection port is displaced in position, the fluid can flow evenly in the measurement flow path, thereby facilitating improvement of measurement accuracy. In addition, even when the measured fluid has fluctuations, it is possible to provide fluid flow into the measurement flow channel with reduced fluctuations caused by the channel opening having a small hole size, thereby improving measurement accuracy even in When fluctuating flow occurs. Furthermore, due to the small hole size of the channel opening of the non-uniform flow suppressor, it is possible to reduce the amount of dust and/or dirt entering the measuring part, thereby increasing the reliability of the measurement operation along the measuring flow channel .

Alternatively, another ultrasonic flowmeter of the present invention includes: a measurement flow channel through which the fluid to be measured flows; ultrasonic transducers respectively arranged at the upstream end and the downstream end opposite to each other along the measurement flow channel; an upstream hole and a downstream hole, the Holes are used to expose the ultrasonic transducers to the measurement flow channel, wherein at least one of the holes comprises a plurality of isolated channels extending along the propagation direction of the ultrasonic waves. Sensitivity is then substantially not reduced due to the ultrasonic waves propagating through the fluid in the isolated channel. Furthermore, due to the separation of the channels, it is possible to maintain the rectilinear characteristics of the ultrasonic waves and achieve their desired transmission/reception. In addition, the orifice flow channel in the hole provided along the side surface of the flow channel is divided into small parts, whereby swirl is less likely to occur, and it is possible to reduce the flow rate of fluid flowing into the hole. Thus, it is possible to measure the flow rate correctly even when fluctuations occur.

Alternatively, at least one of the apertures includes a plurality of isolated channels extending along the direction of propagation of the ultrasonic waves. Fluid flow into the orifice can then be reduced by the fluid suppressor and the upper limit of this measurement can be improved. Furthermore, since the ultrasonic wave propagates through the fluid in the isolated channel, there is little drop in sensitivity. Furthermore, due to the separation of the channels, it is possible to maintain the rectilinear characteristics of the ultrasonic waves and achieve their desired transmission/reception. In addition, the hole in the hole provided along the side surface of the flow channel is divided into small parts, whereby swirl is less likely to occur, and it is possible to reduce the flow rate of fluid flowing into the hole. Thus, it is possible to measure the flow rate correctly even when fluctuations occur.

Alternatively, each isolation channel has an inlet surface extending along the vibrating surface of the ultrasonic transducer and an outlet surface extending along the wall of the measurement flow channel. Thus, since ultrasonic waves can enter the isolated channel at a right angle and thus travel through the channel in a straight line, a propagation channel of ultrasonic waves with no reflection and little attenuation can be provided. Furthermore, because the outlet is a smooth surface relative to the wall of the measurement flow channel, there is no disturbance in the fluid in the peripheral layer along the surface of the measurement flow channel. In addition, since the exit surface is calibrated as a radiating surface, ultrasonic waves can be efficiently radiated.

Alternatively, each separation channel of one eyelet extends co-linearly with a corresponding one of the separation channels of the other eyelet. The transmitting surface and the receiving surface are then aligned with each other along the direction of travel of the ultrasonic waves, whereby the attenuation of reflections caused by the partitions in the isolated channels of the opposite apertures can be reduced.

Alternatively, the length of one side of the longitudinal section of each isolation channel is greater than half the wavelength of the ultrasonic wave used for transmission/reception. Therefore, the viscous influence of the separating surface is reduced, thereby providing an isolated channel with little attenuation.

Alternatively, the length of one side of the longitudinal section of each isolation channel is not an integer multiple of the half-wavelength of the ultrasonic wave used for transmission/reception. Thus, resonance in the lateral direction can be suppressed, thereby achieving efficient propagation.

Alternatively, the distance between the isolation channel of the hole and the vibrating surface of a corresponding ultrasonic transducer is an integer multiple of half the wavelength of the ultrasonic waves. Thus, resonance can be made to occur at a half-wave, thereby making it possible to provide effective radiation.

Alternatively, the thickness of each divided portion of the isolation channel is smaller than the wavelength of ultrasonic waves used for transmission/reception. Thus, reflection of ultrasonic waves can be prevented, thereby providing efficient transmission/reception therein.

Alternatively, the isolation channel is formed by fitting a honeycomb grid into the aperture. Thus, by using a grid, it is possible to separate each eyelet longitudinally and transversely.

Alternatively, one of said isolation channels has an opening in the middle of the bore. The aperture is then aligned with the central axis of the ultrasonic transducer, thereby facilitating efficient reception/transmission.

Alternatively, the channel length of each isolation channel is shorter than the wavelength of ultrasonic waves used for transmission/reception. Thus, an ultrasonic propagation path with little attenuation can be provided.

Alternatively, the isolation channel is formed by installing a mesh member in the hole in a direction perpendicular to the direction of propagation of the ultrasonic waves. Thus, it is possible to minimize the length of the channel by dividing the apertures using a mesh member.

Alternatively, each isolation channel includes a communication member at a certain point along its length for communicating the isolation channel with an adjacent isolation channel. Thus, attenuation caused by the partition can be minimized.

Claims (19)

1. ultrasonic flow meter comprises:

Measure flow channel, measured fluid is by wherein flowing;

Ultrasonic transducer is separately positioned on along measuring flow channel upstream extremity respect to one another and downstream end;

Upstream eyelet and downstream eyelet are used to make ultrasonic transducer to be exposed to the measurement flow channel;

The first fluid rejector and the second fluid rejector for flowing forward and the fluid to be measured of reversed flow, are used to reduce measured fluid and flow into eyelet;

Measure control assembly, be used to measure the hyperacoustic travel-time between ultrasonic transducer; And

Calculating unit is used for according to the calculated signals flow of measuring control assembly,

Wherein:

The first fluid rejector that is provided with when fluid flows forward for the eyelet of downstream end is the eyelet seal member with ultrasonic transmission hole;

The second fluid rejector comprises that direction is regulated parts and the inhibition parts that fluctuate, and direction is regulated the flow direction that parts are used to adjust measured fluid, and fluctuation suppresses parts and is used to make the fluctuation that velocity flow profile is even or minimizing is flowed; And

Direction regulates parts and fluctuation inhibition parts are approaching mutually, and is set at inlet end and the endpiece of measuring flow channel,

Wherein, the cancellated mesh members of eyelet seal member for tilting, this structure tilts with respect to horizontal direction.

2. ultrasonic flow meter as claimed in claim 1, wherein, for the first fluid rejector of upstream eyelet setting is an air deflector.

3. ultrasonic flow meter as claimed in claim 1, wherein, for the first fluid rejector of upstream eyelet setting is the eyelet seal member with at least one ultrasonic transmission hole.

4. want 3 described ultrasonic flow meters as right, wherein, the aperture of the eyelet seal member that is provided with for the upstream eyelet is than greater than the aperture ratio for the eyelet seal member of downstream eyelet setting.

5. ultrasonic flow meter as claimed in claim 1, wherein, the first fluid rejector comprises eyelet seal member with at least one ultrasonic transmission hole and the air deflector that is close to this eyelet.

6. ultrasonic flow meter as claimed in claim 5, wherein, the aperture of the eyelet seal member that is provided with for the upstream eyelet is than greater than the aperture ratio for the eyelet seal member of downstream eyelet setting.

7. ultrasonic flow meter as claimed in claim 2, wherein, this air deflector is set at the upstream extremity and the downstream end of this eyelet.

8. ultrasonic flow meter as claimed in claim 5, wherein, this air deflector is set at the upstream extremity and the downstream end of this eyelet.

9. ultrasonic flow meter as claimed in claim 1 wherein, is measured flow channel and is contained rectangle along the xsect perpendicular to the mobile direction of fluid.

10. ultrasonic flow meter as claimed in claim 1 wherein, is measured flow channel and is contained length breadth ratio less than 2 rectangle along the xsect perpendicular to flow direction.

11. ultrasonic flow meter as claimed in claim 1, wherein, eyelet feeds measures flow channel, and the shape that is adopted has the limit that an edge is substantially perpendicular to the direction extension of flowing through the direction of measuring flow channel.

12. ultrasonic flow meter as claimed in claim 1 wherein, is provided with an introducing portion on the upstream extremity of measuring flow channel, it disposes the Non-Uniform Flow rejector, and this Non-Uniform Flow rejector is provided with narrow meshed access portal.

13. ultrasonic flow meter as claimed in claim 1, wherein, the export department that is arranged on the introducing portion on the upstream extremity of measuring flow channel and is arranged on the downstream end of measuring flow channel all disposes the Non-Uniform Flow rejector, and it is provided with narrow meshed access portal.

14. ultrasonic flow meter as claimed in claim 12, wherein, the cross-sectional area of this introducing portion or this export department is greater than the cross-sectional area of measuring flow channel.

15. ultrasonic flow meter as claimed in claim 13, wherein, the cross-sectional area of this introducing portion or this export department is greater than the cross-sectional area of measuring flow channel.

16. ultrasonic flow meter as claimed in claim 12, wherein, the aperture size of the access portal of Non-Uniform Flow rejector is less than the aperture size of the access portal of the second fluid rejector.

17. ultrasonic flow meter as claimed in claim 13, wherein, the aperture size of the access portal of Non-Uniform Flow rejector is less than the aperture size of the access portal of the second fluid rejector.

18. ultrasonic flow meter as claimed in claim 1, wherein, at least one eyelet comprises a plurality of channel isolations that extend along the ultrasonic propagation direction.

19. a ultrasonic flow meter comprises:

Measure flow channel, measured fluid is by wherein flowing;

Ultrasonic transducer is separately positioned on along measuring flow channel upstream extremity respect to one another and downstream end;

Upstream eyelet and downstream eyelet are used to make ultrasonic transducer to be exposed to this measurement flow channel; Be the first fluid rejector of upstream eyelet and the setting of downstream eyelet, be used to reduce measured fluid and flow into eyelet;

The second fluid rejector is arranged on the upstream extremity of measurement flow channel and with respect to eyelet, is used to reduce measured fluid inflow eyelet;

Measure control assembly, be used to measure the hyperacoustic travel-time between the ultrasonic transducer; And

Calculating unit is used for the calculated signals flow according to this measurement control assembly,

Wherein:

The first fluid rejector that is provided with for eyelet is the eyelet seal member with ultrasonic transmission hole; And

The aperture of the eyelet seal member that is provided with for the upstream eyelet is than the aperture ratio greater than the eyelet seal member that is provided with for the downstream eyelet,

Wherein, the cancellated mesh members of eyelet seal member for tilting, this structure tilts with respect to horizontal direction.

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