JP2009122116A - Flow measuring device - Google Patents

Abstract

Only when a measured value of a flow rate indicates an inherent abnormality, an appropriate alarm process can be performed.
A measurement unit that measures a flow rate of a fluid flowing through a flow path, a setting unit 311 that sets a lower limit value regarding a measurement value of the measurement unit, and a measurement value of the measurement unit that is less than the lower limit value A flow rate monitoring unit 313 for performing an alarm process, and an alarm control unit for invalidating the alarm process from the timing when the fluid starts to flow through the flow path until the measurement value of the measurement unit exceeds the lower limit value. 312.
[Selection] Figure 7

Description

  The present invention relates to a measurement technique, for example, a flow rate measuring device.

  Regarding the measurement technique, for example, Patent Document 1 described below describes a technique for monitoring an abnormal state of an amount measured as a physical quantity per unit time such as an electric energy and a flow rate in a building facility, a water treatment system, and the like.

  In this technology, for example, a host computer that is an element of a building equipment monitoring system is a sensor group (measured value data that is instantaneous value data such as voltage, current, water level, etc.) installed on a switchboard or instrument panel in the building. The normal and low limit monitoring process that collects the pulse signal and measurement value data obtained by a normal sensor that detects noise, the electric energy sensor, the flow sensor, etc., and monitors the upper and lower limits of the collected data, and the alarm processing process To do. The upper / lower limit monitoring process includes an upper / lower limit monitoring process for measured value data that is instantaneous data, and an upper / lower limit monitoring process for a pulse signal integrated value obtained from a sensor.

  The host computer monitors whether or not the acquired measurement value data exceeds the predetermined upper limit value or less than the lower limit value for the measurement value data which is instantaneous value data in the upper and lower limit monitoring process of the measurement value data. If the upper limit value is exceeded or less than the lower limit value, predetermined alarm processing is performed in the alarm processing process.

  In addition, the host computer collects each count value for each preset sampling period, obtains the data of the difference between the count values during the sampling period as a pulse signal integrated value, and whether this value exceeds the upper limit value. Whether or less than the lower limit value is monitored, and if the upper limit value is exceeded or less than the lower limit value, predetermined alarm processing is performed in the alarm processing process.

JP 11-337378 A

  According to the above-described prior art, the host computer measures a fluid (gas or liquid) flowing through a building facility, a water treatment system, or the like with a sensor, and presets upper and lower limit monitoring based on the measured value. And a predetermined alarm process can be performed.

  However, according to the prior art, for example, when the building equipment or the water treatment system is once stopped and then started, the flow rate of the fluid gradually increases from zero, as long as the measured flow rate is less than the lower limit value. Even though it is not abnormal, the alarm process is executed. Such a phenomenon occurs because a change in flow rate at the time of startup (at the time of startup) of equipment such as a building facility or a water treatment system is not taken into consideration.

  Therefore, one of the objects of the present invention is to prevent the alarm processing relating to the flow rate from being performed even when there is no abnormality when the equipment is started up.

  In addition, the present invention is not limited to the above-described object, and other effects of the present invention can be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the invention which will be described later. It can be positioned as one of

  One aspect of the flow rate measurement device of the present invention is a measurement unit that measures the flow rate of fluid flowing through a flow path, a setting unit that sets a lower limit value related to the measurement value of the measurement unit, and the measurement value of the measurement unit When the flow rate monitoring unit performs warning processing when the flow rate is less than the lower limit value, the warning processing is disabled until the measurement value of the measurement unit exceeds the lower limit value from the timing when the fluid starts to flow through the flow path. An alarm control unit for controlling.

  As a result, the alarm process becomes invalid from the timing when the fluid starts to flow through the flow path until the measurement value of the measurement unit exceeds the lower limit value. It can be suppressed from being implemented.

  Here, the alarm control unit periodically compares the measurement value of the measurement unit with the lower limit value after the timing, and determines that the measurement value exceeds the lower limit value for the first time, the alarm process is enabled. It is good also as controlling.

  The timing may correspond to a timing at which an equipment device that circulates the fluid into the flow path is activated.

  Furthermore, the setting unit may further set an upper limit value related to the measurement value, and the flow rate monitoring unit may perform the alarm process when the measurement value of the measurement unit exceeds the upper limit value.

  Further, the setting unit receives the signal according to an operation on the operation unit provided in the measurement unit, or according to a setting from an external device that is communicably connected to the measurement unit, the lower limit value, Alternatively, the lower limit value and the upper limit value may be set.

  According to the flow rate measuring device described above, alarm processing is not performed even when the measured value of the flow rate is less than the lower limit value at the time of starting the equipment that circulates the fluid through the flow path. Therefore, appropriate alarm processing can be performed only when the measured value of the flow rate shows a natural abnormality (in other words, unnecessary alarm processing can be suppressed). As a result, the user does not have to deal with an unintended alarm process, and the ease of use (convenience) of the user of the flow rate measuring device can be improved. In addition, since unnecessary alarm processing is suppressed, it is possible to reduce power consumption of the flow rate measuring device.

It is a perspective view of a flow meter concerning one embodiment. It is a perspective view which shows the state which isolate | separated the measurement part of the flowmeter of FIG. 1 from the flowmeter body part. (A) is a front view of the flow meter of FIG. 1, (B) is a side view of the flow meter of FIG. 1 (a view seen from the direction of arrow B in (A)), and (C) is a view of FIG. It is a top view (figure seen from arrow C direction of (A)) of a flow meter. It is sectional drawing in the IV-IV part of the flowmeter of FIG. 3 (B). It is a perspective view which shows the flow sensor provided in the measurement unit of the flowmeter of FIG. FIG. 6 is an end view when the flow sensor of FIG. 5 is viewed from the VI-VI direction. It is a block diagram which shows the functional structure of the control part provided in the measurement unit of the flowmeter of FIG. It is a map which shows the flow-time information collected by the flow meter of FIG. 2 is a data table showing flow rate-time information and flow rate-time information collected by the flow meter of FIG. 1. 1A and 1B show a display unit of the flow meter of FIG. 1 and information displayed on the display unit, in which FIG. 1A shows an instantaneous flow rate, and FIG. 2B shows an integrated value of the instantaneous flow rate. It is a figure which illustrates transition of the flow volume immediately after starting of an installation apparatus measured by the flowmeter of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention.

  1 to 4 show a configuration example of a flow meter according to the present embodiment. The flow meter 1 (flow rate measuring device) of this embodiment is attached to a part of a flow path such as a pipe through which a fluid such as a gas or a liquid flows, and detects an instantaneous flow rate of a gas that is an example of a fluid to be measured. To do. The flow meter 1 can also calculate the amount of gas used (integrated flow rate) by integrating the detected instantaneous flow rate.

  For example, the flow meter 1 includes a flow path unit 2 that is attached to a part of a pipe P through which gas (gas) flows to form a flow path, and a measurement unit 3 that is attached to the flow path unit 2. . The measurement unit 3 includes a flow sensor (flow sensor) 12, a control unit 30 (see FIG. 7), and the like.

  The flow path unit 2 is, for example, a case having a substantially rectangular parallelepiped shape as shown in FIGS. 2 to 4, a pipe 7 having a circular cross section through which gas flows, and a throttle formed in the middle of the pipe 7. A branch channel 9 formed on the upstream side and the downstream side of the mechanism 8 on the upper side of the pipe line 7 (the side on which the measurement unit 3 is attached) and sandwiching the throttle mechanism 8 and communicating the pipe line 7 with the outside; 10 mag. A pipe P is screwed and connected to the upstream side and the downstream side of the pipe line 7. The throttle mechanism 8 has an inner diameter that is smaller than the inner diameter of the pipe line 7 and generates a differential pressure before and after the throttle mechanism 8 in the gas flowing from the upstream pipe P to the downstream pipe P. Function.

  For example, as shown in FIGS. 2 and 4, a concave portion 2 a having a substantially circular shape in plan view and a predetermined depth is formed on the upper surface of the flow path unit 2, and the bypass flow of the measurement unit 3 is formed in the concave portion 2 a. A path forming portion 3b (described later) is fitted. The branch flow path 9 arranged on the upstream side of the throttle mechanism 8 includes a small diameter part on the inner side of the body and a large diameter part on the outer side of the body, and the bypass flow of the bypass flow path forming part 3b of the measurement unit 3 It is connected to a path 3c (described later). Similarly, the branch flow path 10 disposed on the downstream side of the throttle mechanism 8 also includes a small diameter portion on the inner side of the body and a large diameter portion on the outer side of the body, and is connected to the bypass flow path 3c.

  The measurement unit 3 has a housing having a substantially rectangular parallelepiped shape as shown in FIG. 1 to FIG. 4, and a display unit 4 a and an operation unit are disposed on the upper side (opposite the flow path unit 2) of the housing. A display operation panel 4 having 4b is provided. For example, as shown in FIG. 7, the display unit 4a includes a digital display unit (7-segment display) 41 that displays various types of information in a maximum of 5 digits or letters, and a mode that indicates a mode set by operating the operation unit 4b. Indicator lamps 42 and 43.

  For example, one mode indicator lamp 42 is an instantaneous flow rate mode indicator lamp, and the other mode indicator lamp 43 is an integrated flow rate mode indicator lamp. When the instantaneous flow rate mode indicator 42 is lit, it indicates that the unit of the value displayed on the 7-segment display (hereinafter simply referred to as “display”) 41 is the instantaneous flow rate [L / min]. When the integrated flow mode indicator lamp 43 is lit, it can be expressed that the unit of the value displayed on the 7-segment display 41 is the integrated flow [L]. In addition, the arrangement position in the display part 4a of the mode indicator lamps 42 and 43 is arbitrary. As illustrated in FIG. 7, it may be disposed beside the display 41 or may be disposed below (or above) the display 41.

  The display 41 can display the instantaneous flow rate of the detected gas and the integrated value of the instantaneous flow rate under the control of the CPU 31 of the control unit 30 illustrated in FIG. 7, and various memories (information storage means) such as the ROM 32, the EEPROM 33, and the RAM 34. The information stored in can be displayed.

  The information includes, for example, a measurement result (instantaneous flow rate and / or integrated flow rate) by the flow sensor 12, information on elapsed time and time corresponding to the instantaneous flow rate, information on the type of the flow meter 1, flow meter 1 ( Information related to firmware (for example, version information, copyright information, manufacturer division, software identification information, etc.) installed in the measurement unit 3), information on the diversion ratio, functions supported by the measurement unit 3, and setting values for the functions, etc. Any one or a combination of any two or more is included. The diversion ratio is expressed as the ratio of the flow rate of the fluid flowing through the pipe line 7 to the flow rate of the fluid flowing through the branch channel 9, the bypass channel 3 c, and the branch channel 10.

  The operation unit 4b is provided with various operation (input) keys for setting various information display modes (display contents and display format). For example, the operation unit 4b is provided with a left shift key 401, a right shift key 402, a down (DOWN) key 403, an up (UP) key 404, an execution key 405, an input key 406, a display key 407, and the like.

  The left shift key 401, the right shift key 402, the down key 403, and the up key 404 are used, for example, for selection of instantaneous flow rate / integrated flow rate mode, information display content and display format, and the like. The execution key 405 is used, for example, to execute (start) measurement of a gas flow rate (instantaneous value and / or integrated value) by the flow sensor 12. The input key 406 can be used for inputting various information, for example. The display key 407 is used, for example, to change the mode setting or the display contents and display format of the 7-segment display 41.

  Information output (display control) to the display unit 4a (display 41) is performed under the control of the central processing unit (CPU) 31 of the control unit 30 illustrated in FIG. The CPU 31 receives an input signal corresponding to a user operation on the operation unit 4b, and performs appropriate display control on the display unit 4a according to the input signal.

  On the side surface of the housing of the measurement unit 3 shown in FIGS. 2 to 4, a cable connection portion 5 for connecting a power supply cable C and a signal transmission / reception cable C is provided. In addition, a plate-like portion 3 a is fixed to the lower side of the housing constituting the measurement unit 3 (the side on which the flow path unit 2 is attached). As shown in FIGS. 2 and 4, the screw 6 is screwed into the plate-like portion 3 a of the measurement unit 3 and the screw holes formed in the flow path unit 2 and overlapped with each other, whereby the measurement unit 3. Is fixed to the flow path unit 2.

  As shown in FIG. 4, a bypass flow path forming portion 3 b is disposed between the plate-like portion 3 a of the measurement unit 3 and the flow path unit 2. The bypass flow path forming portion 3b is a thin member having a substantially circular shape in a plan view so as to be fitted into the concave portion 2a of the flow path unit 2. The lower surface thereof communicates with the branch flow paths 9 and 10 of the flow path unit 2. A bypass flow path 3c to be connected is formed. A part of the gas flowing through the upstream pipe line 7 of the flow path unit 2 is transferred to the bypass flow path 3c of the measurement unit 3 via the upstream branch flow path 9 due to the differential pressure before and after the throttle mechanism 8. After being led in, it is bypassed (joined) to the downstream pipe line 7 via the branch flow path 10 on the downstream side of the flow path unit 2. The ratio (diversion ratio) between the flow rate flowing through the conduit 7 as the main flow channel and the flow rate flowing through the bypass flow channel 3c is specified in advance by calculation or actual measurement. A packing 11 as shown in FIGS. 2 and 4, for example, is fitted in the recess 2a of the flow path unit 2 and around the bypass flow path forming portion 3b. The airtightness of the space formed by the recess 3a and the recess 2a of the flow path unit 2 can be ensured.

  Here, when the cross-sectional areas of the branch channels 9 and 10 are small, the ratio of the flow rate of the fluid flowing through the pipe line 7 to the flow rate of the fluid flowing through the branch channel 9, the bypass channel 3 c and the branch channel 10. The diversion ratio increases. On the other hand, when the cross-sectional areas of the branch passages 9 and 10 are large, the diversion ratio of the flow rate of the fluid flowing through the pipe line 7 to the flow rate of the fluid flowing through the branch passage 9, the bypass passage 3 c and the branch passage 10. Becomes smaller.

  Thus, the flow path resistance of the fluid changes according to the cross-sectional area of the branch flow paths 9 and 10 and the cross-sectional area of the pipe line 7, and as a result, the diversion ratio changes. Note that the flow path resistance of the fluid does not necessarily depend only on the cross-sectional area of the flow path. For example, even when the lengths of the pipe line 7 and the branch flow paths 9 and 10 change, the flow path resistance of the fluid changes, and as a result, the diversion ratio changes.

  The information on the diversion ratio can be stored in a memory (ROM 32, EEPROM 33 or RAM 34) through the CPU 31 of the control unit 30 shown in FIG. The diversion ratio depends on the flow path resistance of the branch flow paths 9 and 10, the flow path resistance of the pipe line 7, etc., but the resistance of the measurement unit 3 that forms a part of the pipe line 7 by being attached to the flow path unit 2. It can also be changed by. Therefore, the diversion ratio may be different for each measurement unit 3 attached to the flow path unit 2. Therefore, the information related to the diversion ratio may be, for example, the value of the diversion ratio itself, or may be information associated with the diversion ratio, for example, information relating to the model of the measurement unit 3, an identification number, a product number, or the like.

  A flow sensor 12 is provided at the center of the plate-like portion 3 a fixed to the bottom surface of the measurement unit 3. The flow sensor 12 detects the flow velocity or flow rate (instantaneous flow rate) of the gas flowing through the bypass flow path 3c. Various configurations can be adopted as the flow sensor 12, and in the present embodiment, a thermal flow sensor having a diaphragm is exemplarily employed.

  For example, as shown in FIGS. 5 and 6, the flow sensor 12 includes a substrate 20 provided with a cavity 26, an insulating film 25 disposed on the substrate 20 so as to cover the cavity 26, and a heater provided on the insulating film 25. 21, an upstream side resistance thermometer element 22 provided on the upstream side of the heater 21, a downstream side thermometer resistance element 23 provided on the downstream side of the heater 21, and an upstream side of the upstream side thermometer resistance element 22. An ambient temperature sensor 24 is provided.

  A portion of the insulating film 25 covering the cavity 26 constitutes a diaphragm having a small heat capacity and a heat insulating property with respect to the substrate 20. The ambient temperature sensor 24 measures the temperature of the fluid flowing into the bypass flow path 3c. The heater 21 is disposed at the center of the insulating film 25 covering the cavity 26 and is heated so as to be higher than the temperature of the fluid measured by the ambient temperature sensor 24 (for example, 10 ° C.). The upstream resistance temperature sensor 22 is used to detect the temperature upstream of the heater 21, and the downstream temperature resistance element 23 is used to detect the temperature downstream of the heater 21.

  Here, when the fluid in the bypass passage 3c is stationary, the heat applied by the heater 21 is diffused symmetrically in the upstream direction and the downstream direction. Accordingly, the temperatures of the upstream resistance temperature element 22 and the downstream resistance temperature element 23 are equal, and the electrical resistances of the upstream resistance temperature element 22 and the downstream resistance temperature element 23 are equal. On the other hand, when the fluid in the bypass channel 3c flows from the upstream to the downstream, the heat applied by the heater 21 is carried in the downstream direction. Therefore, the temperature of the downstream temperature measuring resistance element 23 becomes higher than the temperature of the upstream temperature measuring resistance element 22.

  Therefore, a difference is generated between the electrical resistance of the upstream resistance temperature sensor 22 and the electrical resistance of the downstream resistance temperature sensor 23. The difference between the electrical resistance of the downstream resistance temperature sensor 23 and the electrical resistance of the upstream resistance temperature sensor 22 has a correlation with the speed and flow rate of the fluid in the bypass passage 3c. Therefore, the speed and flow rate of the fluid flowing through the bypass flow path 3c can be calculated based on the difference between the electrical resistance of the downstream resistance temperature sensor 23 and the electrical resistance of the upstream resistance temperature sensor 22.

  As a material of the substrate 20 shown in FIGS. 5 and 6, silicon (Si) or the like can be used. As a material of the insulating film 25, silicon oxide (SiO2) or the like can be used. The cavity 26 can be formed by anisotropic etching or the like. Further, platinum (Pt) or the like can be used for each material of the heater 21, the upstream resistance temperature sensor 22, the downstream resistance temperature sensor 23, and the ambient temperature sensor 24, and can be formed by a lithography method or the like.

  Further, the measurement unit 3 includes a control unit (electric circuit) 30 that integrally controls various electronic devices, as shown in FIG. For example, the control unit 30 includes an input / output interface (I / F) 35, a communication unit 36, and a timer 37 in addition to the CPU 31, ROM 32, EEPROM 33, and RAM 34 described above.

  In the ROM 32, various control programs are written in advance in addition to algorithms for setting operations and arithmetic processing. The EEPROM 33 is an example of a non-volatile storage unit, and stored information can be rewritten. In addition to the EEPROM 33, a flash memory, a ferroelectric memory (FeRAM), or the like can be used.

  The RAM 34 temporarily stores flow rate data and the like measured by the flow sensor 12. The I / F 35 inputs and outputs control signals and the like with an external device of the flow meter 1. The communication unit 36 transmits / receives information to / from an external device of the flow meter 1. The timer 37 is an example of a time measuring unit that measures an elapsed time from an arbitrary reference time.

  The EEPROM 33 is detachably attached to the flow meter 1 under the control of the CPU 31, and stores information related to the instantaneous flow rate detected by the flow sensor 12 and information related to the elapsed time measured by the timer 37. The information stored in the EEPROM 33 can be output to an external device through the I / F 35 or the communication unit 36, for example.

  The CPU 31 reads various control programs in the ROM 32 and performs various information processing and device control. For example, the CPU 31 receives an input signal corresponding to the operation of the operation unit 4b by the user, and starts collecting information on the instantaneous gas flow rate and information on the elapsed time (hereinafter referred to as “flow rate-time information”). .

For example, when the user presses the execution key 405 in a state where the flow meter 1 is activated and the information can be collected but the information is not yet collected, the CPU 31 activates the timer 37 to operate the user. The measurement of the elapsed time from the input time (arbitrary reference time) is started, and the detection of the instantaneous gas flow rate by the flow sensor 12 is started. Then, as illustrated in FIG. 8 and FIG. 9, the CPU 31 detects an instantaneous gas flow rate (Q ₁ , Q ₂ ,..., Q _N−1 , Q _N ) detected by the flow sensor 12 and a timer at each detection. The elapsed times (T ₁ , T ₂ ,..., T _N−1 , T _N ) measured in 37 are associated with each other and stored in the EEPROM 33 shown in FIG.

  The detection interval (sampling cycle) and the number of detections of the instantaneous flow rate in the flow sensor 12 and the cycle of the measurement time in the timer 37 can be set as appropriate according to the specifications of the flow meter 1, usage conditions, and the like. For example, the timer 37 has a measurement cycle of 800 minutes (13 hours and 20 minutes), and the timer 37 measures the instantaneous flow rate at intervals of 10 minutes while the timer 37 measures the time of 800 minutes from the time when the user inputs an operation. It can be set to detect 80 times at (sampling period: 10 minutes).

  The CPU 31 reads out information related to the flow dividing ratio from, for example, the ROM 32 or the EEPROM 33, and based on the information related to the flow dividing ratio and the detection value of the flow sensor 12 (the flow rate of the gas flowing through the bypass flow path 3c), FIG. It is possible to calculate (convert) the flow rate of the fluid flowing through the pipe line 7 (pipe P). The obtained value can be stored in, for example, the EEPROM 33 shown in FIG.

In addition, the CPU 31 receives an input signal corresponding to the operation of the operation unit 4b by the user, inputs the collection start time of the flow rate-time information, and the elapsed time stored in the EEPROM 33 based on the input information collection start time. Can be converted into information related to time. For example, as shown in FIG. 9, the instantaneous flow rate (Q ₁ , Q ₂ ,..., Q ₇₉ , Q ₈₀ ) of gas detected 80 times at 10 minute intervals in the flow sensor 12 and measured by a timer 37 at each detection. Assume that stored elapsed times (T ₁ (10 minutes), T ₂ (20 minutes),..., T ₇₉ (790 minutes), T ₈₀ (800 minutes)) are stored in association with each other. . In such a case, assuming that the collection start time of the flow rate-time information (time when the operation of the timer 37 is started) is “8:00”, the CPU 31 shown in FIG. 7 determines each elapsed time (T ₁ , T ₂ , ..., T ₇₉ , T ₈₀ ) are converted into times (8:10, 8:20,..., 21:10, 21:20) and stored in the EEPROM 33. Thereby, “flow rate-time information” is converted into “flow rate-time information”. The collection start time “8:00” may be determined by the operator looking at the clock and operating the operation key of the operation unit 4b.

  When the instantaneous flow rate mode is set by the operation of the operation unit 4b, the CPU 31 turns on the instantaneous flow rate mode indicator lamp 42 of the display unit 4a as shown in FIG. The value obtained by converting the detected value in the flow sensor 12 into the instantaneous flow rate of the gas flowing through the pipe P) can be displayed on the display 41. On the other hand, when the integrated flow mode is set by the operation of the operation unit 4b, the CPU 31 shown in FIG. 7 turns on the integrated flow mode indicator lamp 43 of the display unit 4a to detect it as shown in FIG. 10B. The integrated value of the instantaneous gas flow rate can be displayed on the display 41. When the integrated value of the instantaneous flow rate is 6 digits or more, the CPU 31 can also display an upper digit of 6 digits or more and a lower digit of 5 digits or less alternately on the display 41 every predetermined time.

  In addition, although the Example using only one set was demonstrated, it is good to use two sets of displays if a cost permits. Visibility is improved by displaying information on elapsed time on one display and displaying flow rate information corresponding to the other display. Alternatively, the visibility is improved by displaying the display items as characters on one display and displaying numerical values on the other display. Furthermore, it is possible to improve the recognition using a display capable of displaying a plurality of items, such as a liquid crystal display or a dot matrix type display.

Further, the CPU 31 causes the EEPROM 33 to store additional flow rate information in each detection period of the instantaneous flow rate (measurement cycle of the timer 37) in addition to the information related to the detected instantaneous flow rate and the information related to the elapsed time or time corresponding thereto. The additional flow rate information can be displayed on the display unit 4a. For example, as shown in FIG. 8, the CPU 31 stores information on the maximum value Q _MAX , the minimum value Q _MIN, and the average value Q _AVE in each detection period (0 to T _N ) of the instantaneous flow rate in the EEPROM 33 as additional flow rate information. The additional flow rate information can be stored on the display 41.

At this time, the CPU 31 stores the integrated value of the instantaneous flow rate in each detection period (0 to T _N ) and information related to the integrated value of the instantaneous flow rate in each sampling period (for example, T _{1 to} T ₂ ) in the EEPROM 33 as additional flow rate information. The additional flow rate information can be displayed on the display 41.

  Further, the CPU 31 uses various kinds of information (information relating to the instantaneous flow rate and information relating to the elapsed time / time corresponding to the instantaneous flow rate) stored in the EEPROM 33 via the communication unit 36 using wireless communication or wired communication. Can be transferred to an external device of the flow meter 1. The external equipment includes a portable terminal device for setting various functions for the flow meter 1 and automatically reading the flow rate integrated value.

  Further, as illustrated in FIG. 7, the CPU 31 of this embodiment has functions as a setting unit (flow rate monitoring value setting unit) 311, a determination unit 312, and a flow rate monitoring unit 313.

  The CPU 31 functioning as the flow rate monitoring value setting unit 311 can set a threshold (a lower limit value or a combination of a lower limit value and an upper limit value) related to the flow rate measured using the flow sensor 12. The threshold value (hereinafter also referred to as “flow rate monitoring value”) may be stored in advance as a default value in the ROM 32, the EEPROM 33, or the RAM 34, or may be set and changed by the user.

  For example, the CPU 31 may store and set the flow rate monitoring value in the EEPROM 33 or the RAM 34 by receiving a signal according to the setting operation of the flow rate monitoring value for the operation unit 4b by the user, or the I / F 35 or the communication unit. The flow rate monitoring value received from the external device connected to be communicable with the external device by 36 may be stored and set in the EEPROM 33 or the RAM 34.

  The CPU 31 functioning as the determination unit 312 monitors the flow rate measurement result (for example, instantaneous flow rate) by the flow sensor 12. Illustratively, the determination unit 312 determines whether or not the measurement result by the flow sensor 12 exceeds the flow rate lower limit value from the timing when the gas starts to flow through the pipe P (pipe line 7). The timing may correspond to, for example, a timing at which an equipment device that circulates gas through the pipe P (pipe line 7) is activated. In this case, an activation signal for the equipment may be input to the CPU 31. The input of the activation signal may be automatically performed in conjunction with the activation of the facility device, or may be manually performed by the user operating the operation unit 4b.

  The determination unit 312 periodically compares the flow rate measurement result by the flow sensor 12 with the flow rate monitoring value (flow rate lower limit value) set by the flow rate monitoring value setting unit 311, and the flow rate measurement result is the first time the flow rate monitoring value is obtained. Judge whether or not it has been exceeded. When determining that the flow rate measurement result exceeds the flow rate monitoring value for the first time, the determination unit 312 gives a monitoring execution instruction (trigger) to the flow rate monitoring unit 313.

  In addition, the period (interval) of the comparison is, for example, in the pipe P (pipe line 7) of the flow path unit 2 when an equipment device that circulates gas to the pipe P (pipe line 7) such as an air conditioner is activated. What is necessary is just to set it as a period sufficiently shorter than the time normally required until the flow measurement result by the flow sensor 12 exceeds a flow volume lower limit after gas begins to distribute | circulate.

  The period may be stored in advance in the ROM 32, the EEPROM 33, or the RAM 34 as a default value, or may be set and changed by the user. As the cycle is set shorter, the accuracy of determination can be improved. The determination result by the determination unit 312 can be stored in the EEPROM 33 or the RAM 34. The determination result may be output to an external device via the I / F 35 or the communication unit 36, or may be output and displayed on the display unit 4a.

  When receiving a monitoring execution instruction (trigger) from the determination unit 312, the CPU 31 functioning as the flow rate monitoring unit 313 monitors the measurement result of the flow sensor 12 based on the flow rate monitoring value.

  Illustratively, when only the flow rate lower limit value is set as the flow rate monitoring value, the flow rate monitoring unit 313 periodically compares the flow rate measurement result with the flow rate lower limit value, It is monitored whether or not the flow rate measurement result is less than the lower limit value of the flow rate (that is, whether or not the flow rate measurement result is once less than the lower limit value after the flow rate lower limit value is exceeded). When the flow rate measurement result is less than the lower limit flow rate, the flow rate monitoring unit 313 performs an alarm process. For example, the flow rate monitoring unit 313 generates a flow rate measurement result that is less than the lower limit value of the flow rate (detection of abnormal flow rate) and / or an alarm (alert) as an example of alarm information.

  When both the flow rate lower limit value and the flow rate upper limit value are set as the flow rate monitoring value, the flow rate monitoring unit 313 compares the flow rate measurement result with both the flow rate lower limit value and the flow rate upper limit value. Whether the flow rate upper limit value is exceeded and whether the flow rate lower limit value is reached are monitored. When the flow rate measurement result exceeds the flow rate upper limit value or becomes less than the flow rate lower limit value, the flow rate monitoring unit 313 performs an alarm process. For example, the flow rate monitoring unit 313 generates an abnormal flow rate detection and / or alarm (alert) as an example of alarm information.

  Note that the monitoring cycle by the flow rate monitoring unit 313 may be stored in advance in the ROM 32, the EEPROM 33, or the RAM 34 as a default value, or may be set and changed by the user. As the monitoring cycle is set shorter, the abnormal flow monitoring (detection) accuracy can be improved.

  The alarm information generated by the flow rate monitoring unit 313 can be output to the external device and / or the display unit 4a of the flow meter 1 via the I / F 35 or the communication unit 36, for example. Part or all of the functions of the flow rate monitoring unit 313 may be integrated with the functions of the determination unit 312.

  That is, the CPU 31 (determination unit 312) of the present example measures the measurement result until the measurement result by the flow sensor 12 exceeds the lower limit of the flow rate after the gas starts to flow in the pipe P (pipe line 7) of the flow path unit 2. Is used as an example of an alarm control unit that invalidates the monitoring (alarm output) by the flow rate monitoring unit 313. And if a measurement result exceeds a flow volume lower limit, judgment part 312 will perform control which validates monitoring (alarm output).

  As a result, it is possible to prevent an extra alarm from being issued at the initial stage when the equipment that circulates the gas in the pipe P (pipe line 7) is activated and operated and the gas begins to circulate in the pipe line 7. It becomes possible.

A specific example of the alarm control as described above will be described below with reference to FIG.
The flow velocity measured by the flow sensor 12 is output to the control unit 30 that is an electric circuit. For example, in the RAM 31 that is the CPU 31 and the work area, the control unit 30 multiplies the cross-sectional area of the flow path in which the flow sensor 12 is located by the flow velocity that is the measurement result described above, thereby obtaining an instantaneous flow rate q [L / min. ] Is calculated. The CPU 31 may calculate the integrated flow rate Q [L] by integrating the instantaneous flow rate q for a predetermined time.

  Here, it is assumed that the production line is stopped at the manufacturing factory or the like, for example, at the end of the previous day, and then activated and operated (operated) again at the start of the next day. In this case, the equipment including the flow path unit 2 incorporated in the production line can also be stopped / started according to the stop / start of the production line.

  When the production line is stopped, for example, a stop signal is given to the control unit 30 (CPU 31) of the measurement unit 3, and the flow rate measurement result so far is reset. The reset is performed by the determination unit 312, for example. The reset can be executed by the CPU 31 (determination unit 312) receiving a signal corresponding to a user operation on the operation unit 4b.

  After the reset, the production line is restarted. For example, when the equipment including the flow rate unit 2 is started at the timing indicated by A in FIG. 11, the equipment is connected to the pipe P (see FIG. 1). Distribution begins. Thereby, gas begins to circulate in the pipe P to which the flow path unit 2 is attached, and the flow rate gradually increases from zero.

  As described above, the flow meter 1 attached to the flow path unit 2 has a flow rate of gas flowing through the pipe line 7 in the pipe P periodically at a predetermined sample period by the flow sensor 12 and the control unit 30 (CPU 31). The instantaneous flow rate q) is measured.

  When the flow meter 1 (measurement unit 3) detects that the flow rate measurement result q by the flow sensor 12 that has been zero until then is q> 0, the CPU 31 (determination unit 312) of the control unit 30 has already been described. Start judging. That is, the determination unit 312 performs flow rate monitoring by the flow rate monitoring unit 313 based on the flow rate measurement result q of the flow sensor 12 and the flow rate monitoring value (flow rate lower limit value) set by the function as the flow rate monitoring value setting unit 311. Judge the suitability.

For example, when the flow rate lower limit value q _min is set as the flow rate monitoring value, the determination unit 312 periodically calculates the flow rate q measured by the flow sensor 12 and the flow rate lower limit value q _min at a predetermined sample period. In comparison, it is monitored whether or not the measured flow rate exceeds the flow rate lower limit q _min (q> q _min ).

For example, when the determination unit 312 determines that the condition of timing q> q _min indicated by B in FIG. 11 is satisfied, the determination unit 312 gives a monitoring execution instruction (trigger) to the flow rate monitoring unit 313 and the flow rate monitoring unit 313. Enables flow monitoring by. As a result, the flow rate monitoring unit 313 starts monitoring the flow rate of the pipeline 7. In other words, the determination unit 312 controls the monitoring by the flow rate monitoring unit 313 to an invalid state by not giving a monitoring execution instruction to the flow rate monitoring unit 313 while the condition of q> q _min is not satisfied.

Upon receiving the monitoring execution instruction, the flow rate monitoring unit 313 receives the flow rate measurement result q of the flow sensor 12 and the flow rate lower limit value q _min (if the flow rate upper limit value q _max is set together, the flow rate lower limit value q _min and the flow rate are set. compares the upper limit value q _max) periodically monitors whether the flow rate measurement result q is equal to or less than the flow rate limit value q _min. When the flow rate measurement result q is less than the flow rate lower limit q _min , the flow rate monitoring unit 313 generates that fact and / or alert as an example of alarm information.

When both the flow rate upper limit q _max in addition to the flow rate lower limit value q _min are set as the flow rate monitoring values, the flow rate monitoring unit 313 sets the flow rate measurement result q, the flow rate lower limit value q _min and the flow rate upper limit value q _max . Comparison with both is periodically performed to monitor whether the flow rate measurement result q exceeds the flow rate upper limit q _max and whether the flow rate lower limit q _min or less.

When the flow rate measurement result q exceeds the flow rate upper limit value q _max or less than the flow rate lower limit value q _min , the flow rate monitoring unit 313 generates that and / or an alert as an example of alarm information.

  The alarm information generated by the flow rate monitoring unit 313 is output to the external device and / or the display unit 4a of the flow meter 1 via the I / F 35 or the communication unit 36, for example. Thereby, the user can know the occurrence of the abnormal flow rate and can take appropriate measures.

As described above, in the flow meter 1 of the present example, when the flow rate (instantaneous flow rate) q measured by the flow sensor 12 in the determination unit 312 exceeds the flow rate lower limit q _min for the first time after the equipment is started. Then, it is determined that the start-up of the equipment including the flow path unit 2 is completed, and the control for enabling the flow rate monitoring by the flow rate monitoring unit 313 is performed. In other words, the determination unit 312 disables the flow rate monitoring by the flow rate monitoring unit 313 until the flow rate (instantaneous flow rate) q measured by the flow sensor 12 exceeds the flow rate lower limit q _min after the equipment device is activated. To control.

Therefore, the alarm processing is prevented from being executed when the flow rate of the gas flowing through the pipe P (the pipe line 7) is less than the flow rate lower limit q _min but is not abnormal as when the equipment is started. it can.

Therefore, during normal operation (operation) after the start-up of the equipment, the warning is given that the gas flow rate in the flow path 7 of the pipe P is inadequate (less than the flow rate lower limit q _min ). The alarm process can be executed according to the general intention. That is, appropriate alarm processing can be performed only when the measured value of the flow rate shows an inherent abnormality (unnecessary alarm processing can be suppressed).

  As a result, the user (maintenance person, manager, etc.) of the flow meter 1 does not have to deal with unintended alarm processing, and the user's ease of use (convenience) can be improved. In addition, since unnecessary alarm processing is suppressed, it is possible to reduce power consumption of the flow meter 1.

  In addition, you may implement said alarm control about an integrated flow rate by making a flow volume lower limit and a flow volume upper limit into the value regarding integrated flow.

  In this embodiment, the CPU 31 receives the input signal corresponding to the operation of the operation unit 4b by the user and starts collecting the flow rate-time information. However, the trigger for starting the collection of the flow rate-time information is shown. Is not limited to this. For example, the CPU 31 may automatically start collecting the flow rate-time information simultaneously with the activation of the flow meter 1 or at an arbitrary timing after the activation.

  In the present invention, “start-up” is a concept including the following matters or items equivalent thereto. (1) The time when power supply to the flow measuring device is started is referred to as “activation”. (2) The time point when power supply to the control unit 30 is started is referred to as “activation”. (3) “Startup” is a time point when a corresponding trigger signal is received from the outside of the flow measurement device by an operator or another controller. (4) A time point at which the flow sensor first detects a fluid flow (or a time point when the flow sensor continues for a predetermined time) is defined as “activation”. (5) After the flow measurement device once detects an alarm, the time point when the corresponding trigger signal is received from the outside of the flow measurement device by an operator or another controller is referred to as “activation”. (6) After the flow rate measuring device once detects an alarm, the time point when the flow sensor first detects the flow of fluid (or the time point when it continues for a predetermined time) is set as “startup”. (7) After the flow rate measuring device detects an alarm, the time when the alarm is canceled by an operator, another controller, or the like is referred to as “activation”. (8) A time point when a predetermined time (predetermined time) has elapsed from the time point (1) to (7) is referred to as “activation”.

  Further, in the present embodiment, an example in which a thermal flow sensor is employed as an example of the flow detection means has been described. However, instead of such a thermal flow sensor, another type (ultrasonic or electromagnetic) flow sensor is used. Can also be employed as an example of the flow rate detection means. Moreover, in this embodiment, although the example which applied this invention to the gas flowmeter was shown, this invention can also be applied to the flowmeter which detects the flow volume of a liquid. Note that the terms “upper” and “lower” used in the above description are expedient expressions, and do not necessarily represent the limitation of the direction with respect to the direction of gravity.

1 Flow meter (flow rate measuring device)
2 channel unit 3 measuring unit 3c bypass channel 4 display operation panel 4a display unit 4b operation unit 401 to 407 operation key 12 flow sensor (flow sensor)
31 Central processing unit (CPU)
311 Setting section (flow rate monitoring value setting section)
312 Judgment unit 313 Flow rate monitoring unit (alarm control unit)
32 ROM (nonvolatile storage means, memory)
33 EEPROM (nonvolatile storage means, memory)
34 RAM (volatile storage means, memory)
35 I / O interface (I / F)
36 communication unit 37 timer (time measuring means)
41 Digital display (7-segment display)
42 Mode indicator (instantaneous flow mode indicator)
43 Mode indicator (integrated flow rate mode indicator)

Claims (8)

A measurement unit for measuring the flow rate of the fluid flowing through the flow path;
A setting unit for setting a lower limit for the measurement value of the measurement unit;
When the measurement value of the measurement unit is less than the lower limit value, a flow rate monitoring unit that performs an alarm process,
From the timing when the fluid starts to flow through the flow path until the measurement value of the measurement unit exceeds the lower limit value, an alarm control unit that invalidates the alarm process;
A flow rate measuring device comprising: The alarm control unit
After the timing, the measurement value of the measurement unit is periodically compared with the lower limit value, and when the measurement value is determined to exceed the lower limit value for the first time, the alarm process is effectively controlled. The flow rate measuring device according to claim 1.   The flow rate measuring device according to claim 1, wherein the timing corresponds to a timing at which an equipment device that circulates the fluid into the flow path is activated. The setting unit
Further setting an upper limit on the measured value,
The flow rate monitoring unit
The flow rate measuring device according to any one of claims 1 to 3, wherein the alarm processing is performed when a measured value of the measuring unit exceeds the upper limit value.   The said setting part performs the setting of the said lower limit by receiving the signal according to operation with respect to the operation part provided in the said measurement unit, The any one of Claims 1-4 characterized by the above-mentioned. The flow rate measuring device described.   5. The flow rate measurement according to claim 1, wherein the setting unit sets the lower limit value according to a setting from an external device that is communicably connected to the measurement unit. apparatus.   The flow rate measuring device according to claim 4, wherein the setting unit sets the lower limit value and the upper limit value by receiving a signal corresponding to an operation on an operation unit provided in the measurement unit. .   The flow rate measuring device according to claim 4, wherein the setting unit sets the lower limit value and the upper limit value according to a setting from an external device that is communicably connected to the measurement unit.