TWI881613B - Pipeline fluid pressure fluctuation sensing device - Google Patents

Abstract

A pipeline fluid pressure fluctuation sensing device is provided. The pipeline fluid pressure fluctuation sensing device includes a housing, a vibration membrane, a fixed ring, a pressure balance hole, a magnetic element and a magnetic sensing element. The housing includes an open end and a closed end opposite to each other. The open end is used to connect the fluid pipeline. The vibration membrane is located inside the housing. The vibrating membrane is displaced due to pressure changes in the fluid pipeline. The fixed ring is connected between the housing and the vibration membrane. The pressure balancing hole is passing through the fixed ring and the pressure balancing hole is used to balance the pressure at the opposite sides of the vibration membrane. The magnetic element is arranged in conjunction with the vibration membrane, and the magnetic element produces a displacement change due to the movement of the vibration membrane. The magnetic sensing element is arranged outside the housing, and the magnetic sensing element senses the displacement change of the magnetic element.

Description

Pipeline fluid pressure fluctuation sensing device

This disclosure relates to a sensing device for sensing pressure fluctuations of fluid in a pipeline.

The transportation safety of flammable fluids for industrial use is a very important issue. It is necessary to apply sensing technology to monitor pipeline leakage to avoid loss of life, property and economy caused by pipeline leakage.

Generally speaking, different types of sensors such as pressure sensors and acoustic sensors are often used to detect pressure changes and acoustic wave propagation caused by pipeline leakage for the purpose of monitoring pipeline leakage.

In the design of these sensors in the conventional technology, the sensing element and circuit are placed in the sensor housing, and then the wires pass through the housing to connect to the external measuring device. The circuit is located in the flammable fluid in the sensor housing, or the wires pass through the pressure boundary, which may leak over a long period of time. These factors lead to safety concerns in operating in a flammable fluid environment.

In addition, the design of pressure sensors in conventional technology uses the deformation of the diaphragm to sense pressure, but this diaphragm is also a part of the pressure boundary. Compared with the housing, this diaphragm is the structurally weaker part of the pressure boundary.

In addition, this pressure sensing diaphragm must be strong enough to withstand fluid pressure, which also affects the measurement of small pressure changes.

The disclosed embodiment provides a pipeline fluid pressure fluctuation sensing device to monitor pipeline leakage and avoid industrial accidents.

An embodiment of the present disclosure provides a pipeline fluid pressure fluctuation sensing device, which is used to connect a fluid pipeline. The pipeline fluid pressure fluctuation sensing device includes a housing, a vibrating membrane, a fixing ring, a pressure balance hole, a magnetic element, and a magnetic sensing element. The housing includes an open end and a closed end opposite to each other, and therefore no wire passes through the housing. The open end is used to connect the fluid pipeline. The vibrating membrane is disposed in the housing, and the vibrating membrane is displaced due to the pressure change generated by the fluid pipeline. The fixing ring is connected between the housing and the vibrating membrane. The pressure balance hole is used to balance the pressure on the two opposite sides of the vibrating membrane. The magnetic element is linked to the vibration film, wherein the magnetic element generates a displacement change due to the displacement of the vibration film. The magnetic sensing element is arranged outside the housing, and the magnetic sensing element senses the displacement change of the magnetic element.

Based on the above, the present disclosure uses the magnetic field detection principle. The pressure fluctuation drives the vibrating membrane in the housing. The magnetic element produces a displacement change due to the displacement of the vibrating membrane. The magnetic sensing element senses the displacement change of the magnetic element. This displacement change is converted into an electrical signal by the magnetic sensing element.

Furthermore, the background pressure on both sides of the diaphragm is balanced by the pressure balance hole, which can improve the sensitivity of pressure fluctuation measurement in high pressure environment.

In addition, the present disclosure has no wires passing through the shell, has a complete pressure boundary, has no risk of long-term leakage, and the pressure boundary is not used for sensing, thereby improving the overall strength of the pipeline fluid pressure fluctuation sensing device structure.

In addition, the shell of the present disclosure does not contain any circuit components, thereby improving the explosion-proof safety of the pipeline fluid pressure fluctuation sensing device in a flammable fluid environment.

In order to make this disclosure more clear and easy to understand, the following is a specific example and a detailed description with the attached figures.

50: Fluid pipeline

52: Tube wall

60: Fluid

100,300,400,500,600,700: Pipeline fluid pressure fluctuation sensing device

110,310,410: Shell

112: Open end

114: Closed end

116A: Inner area

116B: Outer area

122,222: Vibrating membrane

124,224: Outer membrane surface

126,226: Inner membrane surface

130:Fixed ring

132A: Inner Surface

132B: Outer surface

140,440,540,640: Pressure balance hole

150: Magnetic components

160,360: Magnetic sensing element

310A,410A: Main body

310B: Extension body

370: Extension rod

410B: Depression

442,642: First pressure balance hole

444,644: Second pressure balance hole

480,680: Low frequency extension tube

482,682: Tube body

484,684:Entrance

486,686:Export port

DP: displacement change

K1, K2: curve

L1: Maximum amplitude

L11,L21: Curve

L11A, L21A: Lines

P: Pressure

Figure 1 is a schematic diagram of an embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 2 is a schematic diagram of an embodiment of the displacement of the vibrating membrane in the pipeline fluid pressure fluctuation sensing device of Figure 1.

Figure 3 is a schematic diagram of an embodiment of the pressure balancing device disclosed herein.

Figure 4 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 5 is a schematic diagram of an embodiment of the displacement of the vibrating membrane in the pipeline fluid pressure fluctuation sensing device of Figure 4.

Figure 6 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 7 is a schematic diagram of a variation of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 8 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 9 is a schematic diagram of other variations of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 10 is a schematic diagram of a test verification of the pipeline fluid pressure fluctuation sensing device disclosed herein.

Figure 11 is a spectrum analysis diagram of the fluctuation signal of a test verification of the pipeline fluid pressure fluctuation sensing device disclosed in this disclosure.

The following is a detailed description of the embodiments and accompanying drawings, but the embodiments provided are not intended to limit the scope of the present disclosure. In addition, the drawings are for illustrative purposes only and are not drawn in original size. For ease of understanding, the same components will be indicated by the same symbols in the following description.

The terms "including", "comprising", "having" and the like mentioned in this disclosure are all open terms, which means "including but not limited to".

In the description of each embodiment, when the terms "first", "second", "third", "fourth", etc. are used to describe the elements, they are only used to distinguish these elements from each other and do not limit the order or importance of these elements.

In the description of each embodiment, the so-called "coupling" or "connection" may refer to two or more elements making direct physical or electrical contact with each other, or making indirect physical or electrical contact with each other, and "coupling" or "connection" may also refer to two or more elements operating or moving with each other.

FIG. 1 is a schematic diagram of an embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein. FIG. 2 is a schematic diagram of an embodiment of the displacement of the oscillating membrane in the pipeline fluid pressure fluctuation sensing device of FIG. 1. Please refer to FIG. 1 and FIG. 2. The pipeline fluid pressure fluctuation sensing device 100 disclosed herein is used to connect a fluid pipeline 50, wherein the fluid pipeline 50 is represented by a dotted line, and the fluid pipeline 50 can be a hydrogen transmission pipeline, a related process pipeline system using hydrogen, and a petrochemical pipeline system. The internal fluid 60 of the fluid pipeline 50 can be a liquid, a gas, or a two-phase flow in which gas and liquid exist simultaneously.

The pipeline fluid pressure fluctuation sensing device 100 includes a housing 110, a vibration membrane 122, a fixed ring 130, a pressure balance hole 140, a magnetic element 150, and a magnetic sensing element 160. The material of the housing 110 can be a non-ferromagnetic metal, a non-magnetic material, or a non-metal material that does not affect the magnetic field. The housing 110 can be of any shape, and the housing 110 includes an open end 112 and a closed end 114 opposite to each other. For example, the housing 110 is a cylindrical housing, one end of which is defined as the open end 112, and the bottom of the cylindrical housing is defined as the closed end 114. There is no circuit between the open end 112 and the closed end 114, that is, there is no wire connected to the shell 110. The open end 112 is used to connect the pipe wall 52 in the fluid pipeline 50. The shell 110 and the fluid pipeline 50 are connected by flange or thread or other commonly used connection methods for general pipelines.

The vibration membrane 122 is disposed inside the housing 110. The material of the vibration membrane 122 includes an elastic body structure, a polytetrafluoroethylene (Teflon) structure, or a metal structure. The material of the vibration membrane 122 can be adjusted according to the actual situation. The shape of the vibration membrane 122 is not limited to a flat shape. One side of the vibration membrane 122 is an outer membrane surface 124, and the other side of the vibration membrane 122 is an inner membrane surface 126. The vibration membrane 122 divides the housing 110 into an inner area 116A and an outer area 116B. The vibration membrane 122 is displaced due to the fluctuation of the pressure P (as shown in Figure 2) generated by the fluid pipeline 50, wherein the dotted line and the solid line indicate that the vibration membrane 122 vibrates up and down due to the fluctuation of the pressure P.

The fixing ring 130 is connected between the housing 110 and the diaphragm 122. The pressure balance hole 140 is provided through the fixing ring 130, and the pressure balance hole 140 is used to balance the pressure on the opposite sides of the outer membrane surface 124 and the inner membrane surface 126 of the diaphragm 122. In other embodiments, the pressure balance holes can also be two holes on the housing, one of which is connected to the outer area 116B, and the other is connected to the inner area 116A.

The magnetic element 150 is disposed below the inner membrane surface 126 of the vibrating membrane 122, but can also be disposed above the outer membrane surface 124. The magnetic element 150 is disposed in conjunction with the vibrating membrane 122. The magnetic element 150 can be a magnet, a ferromagnetic metal, or any magnetically permeable element. The magnetic sensing element 160 is disposed outside the housing 110. The magnetic sensing element 160 can include a coil, and its form can be a magnetoelectric or eddy current sensor, which is used to sense the magnetic field change caused by the displacement change DP of the magnetic element 150 inside the housing 110.

Under this configuration, as shown in FIG. 2, the pressure P (as shown in FIG. 2) generated by the fluid pipeline 50 fluctuates and changes, causing the vibrating membrane 122 to displace. The magnetic element 150 also generates a displacement change DP due to the displacement of the vibrating membrane 122, and the magnetic sensing element 160 senses the displacement change DP of the magnetic element 150. The displacement change DP is converted into an electrical signal by the magnetic sensing element 160. The background pressure on both sides of the outer membrane surface 124 and the inner membrane surface 126 of the vibrating membrane 122 is balanced by the pressure balance hole 140, which can improve the sensitivity of pressure fluctuation measurement in a high pressure environment.

Furthermore, the present disclosure has no wires passing through the housing 110, has a complete pressure boundary, has no risk of long-term leakage, and the pressure boundary is not used for sensing, thereby improving the overall strength of the pipeline fluid pressure fluctuation sensing device structure.

In addition, the shell 110 disclosed herein does not contain circuit components, thereby improving the explosion-proof safety of the pipeline fluid pressure fluctuation sensing device 100 in a flammable fluid environment.

FIG. 3 is a schematic diagram of an embodiment of the pressure balance device disclosed herein. Referring to FIG. 3 and FIG. 2, the fixed ring 130 is, for example, a ring and can be a ring-shaped support seat. The fixed ring 130 has an inner circumference 132A and an outer circumference 132B. The outer circumference 132B is mounted and fixed to the inner surface of the housing 110. The inner circumference 132A has a hole. The inner circumference 132A is connected to the vibration membrane 122, so that the vibration membrane 122 is mounted in the inner circumference 132A of the fixed ring 130. The pressure balance hole 140 is penetrated between the inner circumference 132A and the outer circumference 132B of the fixed ring 130. The pressure balance hole 140 can also be opened on the vibration membrane 122.

FIG. 4 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein. FIG. 5 is a schematic diagram of an embodiment of the displacement of the oscillating membrane in the pipeline fluid pressure fluctuation sensing device of FIG. 4. Please refer to FIG. 4 and FIG. 5. The difference between the pipeline fluid pressure fluctuation sensing device 300 disclosed herein and the pipeline fluid pressure fluctuation sensing device 100 of FIG. 1 and FIG. 2 is that the pipeline fluid pressure fluctuation sensing device 300 disclosed herein further includes an extension rod 370, and a housing 310 and a magnetic sensing element 360 associated with the extension rod 370.

In detail, the vibration membrane 222 includes an outer membrane surface 224 and an inner membrane surface 226 that are opposite to each other. The extension rod 370 is connected between the vibration membrane 222 and the magnetic element 150, so that the vibration membrane 222, the extension rod 370 and the magnetic element 150 form a linkage component. The displacement of the vibration membrane 222 will link the extension rod 370 to cause the displacement of the magnetic element 150. In response to the setting of the extension rod 370, the housing 310 includes a body 310A and an extension body 310B, and the extension body 310B is connected to the body 310A. The material of the housing 310 can be a non-ferromagnetic metal, a non-magnetic material or a non-metal material that does not affect the magnetic field. The magnetic element 150 and a part of the extension rod 370 are located in the extension body 310B. The extension body 310B is a protruding accommodation space connected to the bottom of the main body 310A. Its shape can be determined by the length of the extension rod 370. In other embodiments, if the length of the extension rod 370 is adjusted, the extension body 310B may not be required, so that the extension rod 370 is only located in the main body 310A.

In one embodiment, the extension rod 370 is a rod or other component with equivalent functions. The material of the extension rod 370 can be a non-magnetic material. In other embodiments, the extension rod 370 can also be a magnetic material.

In addition, the magnetic sensing element 360 is located outside the extension body 310B, and the magnetic sensing element 360 is, for example, a ring-shaped structure. Through the configuration of the extension rod 370, the magnetic element 150 is set at one end of the extension rod 370 away from the vibration film 222, so that the magnetic element 150 can be close to the magnetic sensing element 360, so that the magnetic sensing element 360 can better sense the displacement change of the magnetic element 150.

Under this configuration, as shown in FIG. 5, the dotted line indicates the position of the diaphragm 222 in FIG. 4. The diaphragm 222 is displaced due to the fluctuation of the pressure P in the fluid pipeline. The extension rod 370 and the magnetic element 150 at its end also produce a displacement change DP due to the displacement of the diaphragm 222. The magnetic sensing element 360 senses the displacement change DP of the magnetic element 150. The displacement change DP is converted into an electrical signal by the magnetic sensing element 360.

FIG. 6 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein. Referring to FIG. 6, the pipeline fluid pressure fluctuation sensing device 400 disclosed herein is different from the pipeline fluid pressure fluctuation sensing device 300 of FIG. 4 and FIG. 5 in that the pipeline fluid pressure fluctuation sensing device 400 disclosed herein further includes a low-frequency extension tube 480 for measuring low-frequency (such as infrasonic range below 20 Hz) pressure fluctuations, and the type of the pressure balance hole 440 associated with the low-frequency extension tube 480.

The low-frequency extension tube 480 is disposed in the housing 310 and is located in the inner region 116A of the body 310A. The low-frequency extension tube 480 includes a tube body 482, an inlet end 484, and an outlet end 486. There are two pressure balance holes 440, including a first pressure balance hole 442 and a second pressure balance hole 444. The fixing ring 130 is connected between the housing 310 and the diaphragm 222. The first pressure balance hole 442 and the second pressure balance hole 444 are respectively penetrated at different positions of the fixing ring 130, wherein the second pressure balance hole 444 is connected to the inlet end 484 of the low-frequency extension tube 480, so that the tube body 482 is connected to the fixing ring 130. The first pressure balance hole 442 is not connected to the tube 482, and its position and function can be regarded as the pressure balance hole 140 in Figures 1 to 5 above.

Under this configuration, the present embodiment coexists the low-frequency extension tube 480 and the first pressure balance hole 442 on the same pipeline fluid pressure fluctuation sensing device 400. In use, the first pressure balance hole 442 and the second pressure balance hole 444 can be selected and applied, such as closing the second pressure balance hole 444, that is, the function and operation principle are similar to the aforementioned FIG. 5; if the first pressure balance hole 442 is closed, the low-frequency (such as the infrasonic range below 20 Hz) pressure fluctuation is measured by the low-frequency extension tube 480, so that the pipeline fluid pressure fluctuation sensing device 400 disclosed in the present invention can cover the fluctuation frequency range to the infrasonic range (below the infrasonic range below 20 Hz), and can effectively measure and capture low-frequency fluctuations. In addition, the two ends of the low-frequency extension tube 480 are open at the inlet end 484 and the outlet end 486. The second pressure balance hole 444 is connected to the inlet end 484 of the low-frequency extension tube 480, and the pressure on both sides of the diaphragm 222 can also be balanced.

In one embodiment, the low frequency extension tube 480 is based on the Helmholtz resonance principle, and its effect depends on the tube diameter and tube length. The Helmholtz resonance equation (1) is as follows:

In the above equation (1), v is the speed of sound. A is the cross-sectional area of the tube 482, which can be calculated from the diameter of the tube 482, L is the length of the tube 482, and V is the cavity volume, which is the volume of the area below the vibrating membrane 222, for example, the shell 310.

In one embodiment, the tube 482 may be a spiral tube, and the tube 482 is disposed around the outer periphery of the extension rod 370. The spiral configuration avoids the extension rod 370, so that the extension rod 370 can still move in the central part of the tube 482, and can be used to reduce the length of the tube 482 in the longitudinal direction, so that it can be accommodated in the housing 310, thereby improving the convenience of use. In other embodiments, the tube 482 can also be disposed in other forms according to the shape and size of the housing 310.

FIG. 7 is a schematic diagram of a modified embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein. Please refer to FIG. 7. The difference between the pipeline fluid pressure fluctuation sensing device 500 disclosed herein and the pipeline fluid pressure fluctuation sensing device 400 of FIG. 6 is that the pipeline fluid pressure fluctuation sensing device 500 disclosed herein has only one pressure balance hole 540, and the pressure balance hole 540 is connected to the inlet end 484 in the low-frequency extension tube 480.

FIG. 8 is a schematic diagram of another embodiment of the pipeline fluid pressure fluctuation sensing device disclosed herein. Please refer to FIG. 8 . The difference between the pipeline fluid pressure fluctuation sensing device 600 disclosed herein and the pipeline fluid pressure fluctuation sensing device 500 of FIG. 7 and the pipeline fluid pressure fluctuation sensing device 400 of FIG. 6 is that the low-frequency extension tube 680 in the pipeline fluid pressure fluctuation sensing device 600 disclosed herein is disposed outside the housing 310, and the corresponding pressure balance hole 640 includes a first pressure balance hole 642 and a second pressure balance hole 644. Different from the aforementioned embodiments, the fixing ring 130 of the present embodiment is connected between the housing 310 and the vibrating membrane 122, but the pressure balance hole 640 is not penetrated through the fixing ring 130, so that the fixing ring 130 has no pressure balance hole. Instead, the first pressure balance hole 642 and the second pressure balance hole 644 are respectively provided at different positions of the housing 310, and the first pressure balance hole 642 is located in the outer area 116B, and the second pressure balance hole 644 is located in the inner area 116A.

The low-frequency extension tube 680 includes a tube body 682, an inlet end 684 and an outlet end 686. The tube body 682 can be a spiral tube. The inlet end 684 is connected to the first pressure balance hole 642 in the outer area 116B, and the outlet end 686 is connected to the second pressure balance hole 644 in the inner area 116A. In this way, the background pressure on both sides of the diaphragm 222 is balanced by the first pressure balance hole 642 and the second pressure balance hole 644, and the low-frequency extension tube 680 is used to measure the pressure fluctuation of the low frequency (such as the infrasound range below 20 Hz). In other embodiments, a pressure balance hole can also be set on the fixed ring 130, and it can be selectively applied with the first pressure balance hole 642 and the second pressure balance hole 644.

FIG. 9 is a schematic diagram of another variation of the pipeline fluid pressure fluctuation sensing device disclosed in the present invention. Referring to FIG. 9, the difference between the pipeline fluid pressure fluctuation sensing device 700 disclosed in the present invention and the pipeline fluid pressure fluctuation sensing device 600 of FIG. 8 is that the present invention does not have an extension rod, and the magnetic element 150 is disposed under the inner membrane surface 226 of the vibrating membrane 222. In addition, since there is no need to accommodate the extension rod, the housing 410, for example, includes a body 410A and a recessed body 410B, and the recessed body 410B is a receiving space formed by concavely forming the bottom of the body 410A, so that the magnetic sensing element 160 is disposed in the recessed body 410B, but is still located outside the body 410A. Since the recessed body 410B is recessed toward the inside of the main body 410A, the magnetic sensing element 160 disposed in the recessed body 410B is closer to the magnetic element 150 and can better sense the displacement change of the magnetic element 150. However, the present disclosure is not limited to this, and the shape of the housing 410 can be adjusted according to the actual type of the magnetic element 150 and the magnetic sensing element 160 to ensure that the magnetic sensing element 160 can sense the magnetic element 150. Therefore, in other embodiments, the housing 110 shown in FIG. 1 can also be applied.

FIG. 10 is a schematic diagram of a test verification of the pipeline fluid pressure fluctuation sensing device disclosed herein, wherein the horizontal axis represents time in seconds, the left vertical axis represents pressure value in bar, and the right vertical axis represents the voltage value measured by the pipeline fluid pressure fluctuation sensing device disclosed herein in volt. Please refer to FIG. 10. In order to verify the response of the pipeline fluid pressure fluctuation sensing device disclosed herein to pressure fluctuations, the pipeline fluid pressure fluctuation sensing device disclosed herein is connected to a 2-inch low-pressure pipeline in air flow for testing. At 3 seconds in Figure 10, a pressure fluctuation is generated through the operation of the valve on the low-pressure pipeline. This fluctuation is shown as curve K1 in Figure 10, and the maximum amplitude L1 is 0.002 bar. The response of the pipeline fluid pressure fluctuation sensing device disclosed in this disclosure under the above pressure fluctuation is shown as curve K2. The peaks and troughs of the curve K2 signal are consistent with the pressure fluctuation of curve K1. This result shows that the pipeline fluid pressure fluctuation sensing device disclosed in this disclosure does have the effect of measuring tiny pressure fluctuations in a pressure environment, which shows the feasibility of the pipeline fluid pressure fluctuation sensing device disclosed in this disclosure.

FIG. 11 is a spectrum analysis diagram of a fluctuation signal of a test verification of the pipeline fluid pressure fluctuation sensing device disclosed in the present invention, wherein the horizontal axis represents frequency, the unit is Hertz (Hz), and the vertical axis is unitless. Please refer to FIG. 11, this embodiment uses the pipeline fluid pressure fluctuation sensing device 400 of FIG. 6 as a test, and the curve L11 in the upper half of FIG. 11 is the result of closing the second pressure balance hole 444, that is, the inlet end 484 of the low-frequency extension tube 480 is closed, and only the first pressure balance hole 442 is opened. The curve L21 in the lower half of Figure 11 is when the first pressure balance hole 442 is closed and the second pressure balance hole 444 is opened, so that the inlet end 484 of the low-frequency extension tube 480 is opened. By comparing these two curves L11 and L21, and the peak values L11A and L21A corresponding to 15Hz, it can be found that the use of the low-frequency extension tube 480 can significantly improve the range of the response to infrasound below 100Hz. In addition, under the same test conditions, the use of the low-frequency extension tube 480 can detect tiny pressure fluctuations of 13Hz and 10Hz, which shows that the pipeline fluid pressure fluctuation sensing device disclosed in this disclosure can indeed cover the fluctuation frequency range to the infrasound range.

In summary, the present disclosure uses the magnetic field detection principle. The pressure fluctuation drives the vibrating membrane in the housing. The magnetic element produces a displacement change due to the displacement of the vibrating membrane. The magnetic sensing element senses the displacement change of the magnetic element. The displacement change is converted into an electrical signal by the magnetic sensing element.

Furthermore, the background pressure on both sides of the vibrating membrane disclosed in the present invention is balanced by the pressure balance hole, which can improve the sensitivity of pressure fluctuation measurement in a high pressure environment.

In addition, the present disclosure has no wires passing through the shell, has a complete pressure boundary, and the pressure boundary is not used for sensing, so there is no risk of long-term leakage, thereby improving the overall strength of the pipeline fluid pressure fluctuation sensing device structure.

In addition, the shell of the present disclosure does not contain any circuit components, thereby improving the explosion-proof safety of the pipeline fluid pressure fluctuation sensing device in a flammable fluid environment.

Furthermore, the present disclosure measures low-frequency (such as infrasonic range below 20 Hz) pressure fluctuations by setting a low-frequency extension tube, so that the pipeline fluid pressure fluctuation sensing device disclosed in the present disclosure can cover the fluctuation frequency range to the infrasonic range (below 20 Hz), and can effectively measure and capture low-frequency fluctuations.

In addition, the tube body of the low-frequency extension tube disclosed in the present invention can be a spiral tube, which reduces the length of the tube body in the longitudinal direction and improves the convenience of use.

Although the present disclosure has been disclosed as above by way of embodiments, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in the relevant technical field may make some changes and modifications within the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the scope defined in the attached patent application.

50: Fluid pipeline

52: Tube wall

60: Fluid

100: Pipeline fluid pressure fluctuation sensing device

110: Shell

112: Open end

114: Closed end

116A: Inner area

116B: Outer area

122: Vibrating membrane

124: Outer membrane surface

126: Inner membrane surface

130:Fixed ring

140: Pressure balance hole

150: Magnetic components

160: Magnetic sensing element

Claims (11)

A pipeline fluid pressure fluctuation sensing device is used to connect a fluid pipeline, and the pipeline fluid pressure fluctuation sensing device comprises: a housing, comprising an open end and a closed end opposite to each other, wherein the open end is used to connect the fluid pipeline; a vibration membrane, arranged in the housing, and the vibration membrane is displaced due to the pressure change generated by the fluid pipeline; a fixed ring, connected between the housing and the vibration membrane; a pressure balance hole, penetrated through the fixed ring , the pressure balance hole is used to balance the pressure on the two opposite sides of the vibrating membrane; a magnetic element is linked to the vibrating membrane, wherein the magnetic element generates a displacement change due to the displacement of the vibrating membrane; an extension rod is connected between the vibrating membrane and the magnetic element, wherein the material of the extension rod is a non-magnetic material or a magnetic material; and a magnetic sensing element is arranged outside the housing, and the magnetic sensing element senses the displacement change of the magnetic element. The pipeline fluid pressure fluctuation sensing device as described in claim 1, wherein the material of the vibration membrane includes an elastic body structure, a polytetrafluoroethylene structure, or a metal structure. As described in claim 1, the pipeline fluid pressure fluctuation sensing device, wherein the fixed ring has an inner peripheral surface and an outer peripheral surface, the outer peripheral surface of the fixed ring is fixed to the shell, and the inner peripheral surface of the fixed ring is connected to the vibrating membrane. The pipeline fluid pressure fluctuation sensing device as described in claim 1 further includes: a low-frequency extension tube, including a tube body, an inlet end, and an outlet end. As described in claim 4, the pipeline fluid pressure fluctuation sensing device, wherein the vibrating membrane divides the shell into an inner area and an outer area, the low-frequency extension tube is located in the inner area, the pressure balance hole includes a first pressure balance hole and a second pressure balance hole, the tube body is connected to the fixed ring, and the second pressure balance hole is connected to the inlet end. As described in claim 4, the pipeline fluid pressure fluctuation sensing device, wherein the vibrating membrane divides the shell into an inner area and an outer area, the low-frequency extension tube is arranged outside the shell, the pressure balance hole includes a first pressure balance hole and a second pressure balance hole, the first pressure balance hole and the second pressure balance hole are respectively penetrated in the shell, and the first pressure balance hole is located in the outer area, the second pressure balance hole is located in the inner area, the inlet end is connected to the first pressure balance hole in the outer area, and the outlet end is connected to the second pressure balance hole in the inner area. As described in claim 6, the pipeline fluid pressure fluctuation sensing device, wherein the magnetic element is disposed under the vibrating membrane, the housing includes a main body and a recessed body, the recessed body is a receiving space formed by recessing the bottom of the main body, and the magnetic sensing element is disposed in the recessed body. A pipeline fluid pressure fluctuation sensing device as described in claim 4, wherein the pipe body is a spiral pipe. As described in claim 4, the pipeline fluid pressure fluctuation sensing device, wherein: the tube is arranged outside the extension rod, the shell includes a main body and an extension body, the extension body is connected to the main body, the magnetic element and a part of the extension rod are located inside the extension body, and the magnetic sensing element is located outside the extension body. The pipeline fluid pressure fluctuation sensing device as described in claim 1, wherein the magnetic element is disposed under the vibrating membrane. A pipeline fluid pressure fluctuation sensing device as described in claim 1, wherein the shell is made of a non-magnetic material.

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