Gas flow measurement device and gas flow measurement system

Abstract

To provide a gas flow measurement device capable of further improving the accuracy of gas flow measurement, and a gas flow measurement system.SOLUTION: A gas flow measurement device 2 includes: a storage unit 21 that stores reference correlation values (e.g., zero reference value), which is a value corresponding to a predetermined flow rate for a correlation value having a correlation with the flow rate of gas in a flow path 13; and a control unit 20. The control unit 20 is configured such that, when the preset condition that estimates that there is no gas usage downstream of the own device is met (S3: YES), the flow path is closed by a shutoff valve 4 for a predetermined first period, and during first period, the average value of the gas flow rate is calculated by the flow rate calculation process for a predetermined second period, and execute a series of correction processing (S4-S7) to correct the reference correlation value stored in the storage unit based on the average value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a gas flow measurement device and a gas flow measurement system for measuring the flow rate of gas in a pipe to which gas is supplied.

Background Art

[0002] Conventionally, for example, fuel gas has been supplied through pipes to gas-consuming households such as individual homes. And, in order to charge or provide a discount service according to the amount of gas used in each household, a gas flow measurement device is attached to the pipe so that the amount of gas used (consumption) for each household can be measured. As such a gas flow measurement device, for example, devices such as ultrasonic type and thermal type are known as those capable of accurately measuring the instantaneous flow rate of gas.

[0003] By the way, Patent Document 1 proposes a flow measurement device aimed at further improving the measurement accuracy of the gas flow rate. Specifically, in Patent Document 1, paying attention to the fact that pulsation (that is, gas pressure fluctuation) occurring in the pipe through which gas flows induces a measurement error, a method for eliminating the measurement error caused by this pulsation is proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a gas flow rate measuring device, the factors that can cause measurement errors are not limited to pulsation. For example, in the case of an ultrasonic gas flow rate measuring device, signals are mutually transmitted and received between ultrasonic sensors provided on each of the upstream side and the downstream side, and a state where the difference in each propagation time at that time is zero is defined as a zero flow rate. However, due to individual differences between sensors, etc., the propagation time difference does not necessarily become zero when the flow rate is zero. In order to eliminate such zero point errors, adjustment (zero point correction) may be necessary when the sensor unit is shipped from the factory.

[0006] Also, even when the sensor unit is installed at the site after shipment, the assembly accuracy of the sensor unit to the flow path unit and the shape of the flow path of the flow path unit can cause zero point errors. Therefore, zero point correction may also be necessary when installing the sensor unit.

[0007] Thus, by performing zero point correction at the time of factory shipment and on-site installation of the sensor unit, the measurement accuracy of the gas flow rate measuring device can be improved. However, it has been found that even when these zero point corrections are performed, zero point errors may occur thereafter, that is, after the sensor unit is installed at the site and operation is started. Note that such problems are not limited to ultrasonic gas flow rate measuring devices, but also apply to other types of gas flow rate measuring devices that can measure instantaneous flow rates, such as thermal types.

[0008] Therefore, an object of the present disclosure is to provide a gas flow rate measuring device and a gas flow rate measuring system that can further improve measurement accuracy.

Means for Solving the Problems

[0009] The gas flow rate measuring device of the present disclosure includes a storage device that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in a flow path, and a control device. The control device executes a signal acquisition process for acquiring a correlation value, a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, and when a preset condition under which it is estimated that there is no use of gas downstream of the own device is satisfied, closes the flow path with a shut-off valve for a predetermined first period, calculates an average value in a predetermined second period for the flow rate of gas calculated by the flow rate calculation process during the first period, and executes a correction process for correcting the reference correlation value stored in the storage device based on the average value.

Advantages of the Invention

[0010] According to the gas flow rate measuring device and the gas flow rate measuring system according to the present disclosure, it is possible to correct a zero point error that occurs after the start of operation and measure the flow rate of gas more accurately.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0012] As described above, by performing zero-point correction on the device when shipping from the factory or installing at the site, it is possible to improve the measurement accuracy of the flow rate. However, the inventors have found that even so, after the operation of the device at the site starts, the measurement accuracy of the flow rate may decrease due to some reason. As a result of examining this cause, it has been found that a drift phenomenon occurs in which the zero point gradually shifts due to a change in the gas type, other environmental factors, or the secular change in the characteristics of the sensors included in the device. Therefore, the present inventor has invented the gas flow rate measuring device and the gas flow rate measuring system according to the present disclosure in order to eliminate the decrease in the measurement accuracy after such operation starts.

[0013] Hereinafter, specific embodiments of such a gas flow rate measuring device and a gas flow rate measuring system will be described. In each embodiment, an example in which an ultrasonic method is adopted as a method for measuring the flow rate of gas is shown, but the present invention is not limited thereto. Any method that can measure the so-called instantaneous flow rate may be used. For example, a configuration adopting a known thermal measurement method may be used.

[0014] (Embodiment 1) The gas flow rate measuring device according to Embodiment 1 includes a storage device that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in the flow path, a shut-off valve that can open and close the flow path, and a control device. The gas flow rate measuring device measures the flow rate of gas in the flow path that can be opened and closed by the shut-off valve. The control device executes a signal acquisition process for acquiring a correlation value, a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, and when a preset condition that it is estimated that there is no use of gas downstream of the own device is satisfied, closes the flow path by the shut-off valve for a predetermined first period, calculates an average value in a predetermined second period for the flow rate of gas calculated by the flow rate calculation process during the first period, and a correction process for correcting the reference correlation value stored in the storage device based on the average value.

[0015] In addition, the gas flow measurement system according to Embodiment 1 includes a flow path body that forms a flow path, a measurement device that is provided in the flow path body, measures a physical quantity having a correlation with the gas flow rate, and outputs a signal, and the above-described gas flow measurement device.

[0016] Note that the configurations of the gas flow measurement device and the gas flow measurement system other than the above described below are optional configurations in this embodiment and are not essential. Also, hereinafter, the same or corresponding elements will be given the same reference numerals throughout all the drawings, and redundant descriptions will be omitted.

[0017] FIG. 1 is a schematic diagram of a gas flow measurement system 1 including a gas flow measurement device 2 according to Embodiment 1. The gas flow measurement system 1 is provided in the middle of a gas pipe 100 that constitutes a gas pipeline network for supplying gas. The gas pipeline network for supplying gas is composed of a pipeline network that extends from a gas supply facility located on the upstream side to a plurality of customer houses located on the downstream side while branching appropriately in the middle. A part of this pipeline network is constituted by the above-described gas pipe 100. In addition, each customer house is equipped with gas-consuming equipment, and the gas flowing through the gas pipe 100 is consumed by this gas-consuming equipment. Examples of the gas-consuming equipment include a gas stove, a gas fan heater, a water heater, a fuel cell system, and the like.

[0018] The gas flow measurement system 1 includes a gas flow measurement device 2 and a flow path unit 3. Among these, the flow path unit 3 has a flow path body 10. The flow path body 10 is composed of a pipe member made of metal, resin, or the like and having a circular or rectangular cross section. The flow path body 10 is provided intervening in the middle of the gas pipe 100, and its internal space communicates with the internal space of the gas pipe 100 to form a gas flow path 13. That is, the flow path body 10 has an upstream opening 11 and a downstream opening 12, and the gas flowing in from the upstream opening 11 flows through the flow path 13 and flows out from the downstream opening 12.

[0019] The flow path 13 of the flow path body 10 includes a measurement area 14 for measuring the flow rate of the gas. The measurement area 14 is an area of the flow path 13 of the flow path body 10 that includes the propagation path of ultrasonic waves described later, and is formed such that the cross-sectional area is constant throughout the entire flow direction of the gas.

[0020] The flow path unit 3 is provided in the flow path body 10 and has a first ultrasonic transceiver 15 and a second ultrasonic transceiver 16 capable of transmitting and receiving ultrasonic waves. These first ultrasonic transceiver 15 and second ultrasonic transceiver 16 constitute a measuring device that measures a physical quantity having a correlation with the instantaneous flow rate of the gas in the flow path 13 and outputs a signal. In the present embodiment, this physical quantity is exemplified by the propagation time of ultrasonic waves.

[0021] In the case of FIG. 1, the first ultrasonic transceiver 15 is arranged on the upstream side in the direction of the gas flow in the flow path body 10, and the second ultrasonic transceiver 16 is arranged on the downstream side of the first ultrasonic transceiver 15. Further, the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 are arranged on the wall portions in the same direction with respect to the flow center line of the flow path 13, with the ultrasonic wave transmission direction directed toward the flow path 13 side. Then, the ultrasonic wave transmitted from the first ultrasonic transceiver 15 is reflected by the inner wall surface of the flow path body 10, passes through a V-shaped path, and is received by the second ultrasonic transceiver 16. The ultrasonic wave transmitted from the second ultrasonic transceiver 16 is reflected by the inner wall surface of the flow path body 10, passes through a V-shaped path, and is received by the first ultrasonic transceiver 15. Thus, a V-shaped ultrasonic wave propagation path 17 is formed between the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16.

[0022] Also, in the case of such a propagation path 17, the propagation of ultrasonic waves from the first ultrasonic transceiver 15 to the second ultrasonic transceiver 16 is in the forward direction with respect to the gas flow, and the propagation of ultrasonic waves from the second ultrasonic transceiver 16 to the first ultrasonic transceiver 15 is in the reverse direction with respect to the gas flow. Therefore, when the gas is flowing, there is a difference Δt between the first propagation time td required for the ultrasonic wave transmitted by the first ultrasonic transceiver 15 to be received by the second ultrasonic transceiver 16 and the second propagation time tu required for the ultrasonic wave transmitted by the second ultrasonic transceiver 16 to be received by the first ultrasonic transceiver 15. And this propagation time difference Δt varies depending on the flow velocity of the gas. Thus, the flow velocity of the gas can be obtained from the propagation time difference Δt, and further, the gas flow rate Q can be obtained based on the flow velocity of the gas and the cross-sectional area of the flow path 13.

[0023] Note that the propagation speed of ultrasonic waves in the gas is sufficiently fast, and the time required to calculate the flow rate Q from the propagation time difference Δt is also extremely short (for example, less than 1 second). Therefore, the gas flow rate Q obtained by the above method is referred to as the instantaneous flow rate, especially when compared with the flow rate obtained by the membrane type flow measurement method.

[0024] By the way, the arrangement of the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 is not limited to that shown in FIG. 1. That is, in FIG. 1, an arrangement in which the propagation path 17 forms a V shape is illustrated, but it is not limited to this. The first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 may be arranged on the upstream side and the downstream side while facing each other across the flow center line, or may be arranged such that the ultrasonic wave transmitted from one is reflected two or more times by the inner wall surface of the flow path body 10 and then received by the other.

[0025] The gas flow rate measuring device 2 is hardware-wise composed of a computer system having one or more processors, memories, and communication interfaces respectively. Also, in terms of a functional configuration, the gas flow rate measuring device 2 includes a control device 20, a storage device 21, and a communication device 22.

[0026] The control device 20 is composed of a processor, an internal memory, etc., and controls the operations of each part of the gas flow measurement device 2 according to a computer program and data stored in a storage device 21 which is an internal memory or an external memory. For example, the control device 20 functions as at least a signal acquisition unit 30, a flow rate calculation unit 31, and a correction unit 32.

[0027] Among these, the control device 20 that functions as the signal acquisition unit 30 receives signals from the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16, and acquires the propagation time difference Δt. This propagation time difference Δt is an example of a correlation value having a correlation with the gas flow rate in the flow path 13 as described above. Also, the control device 20 that functions as the flow rate calculation unit 31 calculates the gas flow rate Q based on the acquired propagation time difference Δt which is the correlation value. The function of the correction unit 32 will be described later.

[0028] The storage device 21 is composed of a volatile memory, a non-volatile memory, etc., stores a computer program and various data, and is readable and writable by the control device 20. For example, the storage device 21 stores a computer program for causing the control device 20 to function as the above-described respective units 30 to 32, etc. Also, the storage device 21 stores the acquired propagation time difference Δt, the calculated flow rate Q, and information regarding a predetermined zero reference value, etc.

[0029] Here, the zero reference value is information indicating the relationship between the actual instantaneous flow rate of the gas and the propagation time difference Δt measured by the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16, and is also referred to as the reference correlation value in the present disclosure. More specifically, the propagation time difference Δt is a correlation value having a correlation with the actual flow rate of the gas in the flow path 13. And this correlation value corresponding to a preset predetermined flow rate is used as the reference correlation value. As an example of such a reference correlation value, in the present embodiment, the reference correlation value when the gas flow rate is zero is used as the zero reference value. Therefore, the zero reference value is the propagation time difference Δt when the gas flow rate is zero.

[0030] Generally, the propagation path from the first ultrasonic transceiver 15 to the second ultrasonic transceiver 16 and the propagation path from the second ultrasonic transceiver 16 to the first ultrasonic transceiver 15 are both the same propagation path 17. Therefore, when no gas is flowing, that is, when the instantaneous gas flow rate is zero, the propagation time difference Δt becomes zero. Accordingly, the design zero reference value is the content that sets the propagation time difference Δt to zero, and such a zero reference value is stored in the storage device 22.

[0031] However, the zero reference value is not limited to the content that sets the propagation time difference Δt to zero. For example, an error may occur in the zero reference value due to individual differences between the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16. Also, an error may occur in the zero reference value based on environmental factors when the gas flow rate measuring device 2 is installed in the gas pipe 100. Therefore, when these errors are corrected (zero point correction), the corrected zero reference value may be stored in the storage device 21, or the zero reference value stored in the storage device 21 may be updated to the corrected value and stored.

[0032] The communication device 22 is composed of a communication interface and relays the communication of information (signals) between the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 and the control device 21. Therefore, the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 are driven according to an instruction from the control device 20 received via the communication device 22 to transmit ultrasonic waves. Also, when the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16 receive ultrasonic waves, a signal corresponding to the received ultrasonic waves is transmitted to the control device 20 via the communication device 22.

[0033] Furthermore, the gas flow measurement system 1 includes a shut-off valve 4. The shut-off valve 4 is provided in the middle of the gas pipe 100 and is composed of a valve body, a motor, and the like. The shut-off valve 4 is connected to the control device 20 via the communication device 22 and can open and close the flow path in the gas pipe 100 according to an instruction from the control device 20. Therefore, when the shut-off valve 4 closes, the flow path 13 is closed and gas does not flow, and when the shut-off valve 4 opens, the flow path 13 is opened and gas can flow through. Note that the shut-off valve 4 may be provided in the flow path main body 10. In addition, the above-described gas flow measurement system 1 operates, for example, by power supply from a battery.

[0034] Next, the operation of the gas flow measurement device 2 will be described with reference to the flowchart of FIG. 2. After the operation starts, the gas flow measurement device 2 executes a signal acquisition process (step S1) and a flow rate calculation process (step S2) to measure the flow rate of the gas flowing through the flow path 13. Specifically, the control device 20 drives the first ultrasonic transceiver 15 and the second ultrasonic transceiver 16, receives signals regarding the propagation times td and tu of ultrasonic waves from each of them, and acquires the propagation time difference Δt from these signals (S1). Then, the flow rate Q is calculated from this propagation time difference Δt and the cross-sectional area of the flow path 13 (S2).

[0035] The processes S1 and S2 related to the calculation of such a flow rate Q are continuously executed at a predetermined period, such as every 2 seconds, and the calculated values are stored in the storage device 21. On the other hand, at an appropriate timing during the process of executing the process related to the calculation of the flow rate Q, it is determined whether or not a predetermined condition set in advance is satisfied (step S3). This condition is a condition under which it can be estimated that there is no gas use downstream of the own device (gas flow measurement device 2). Examples of such a condition include that the current time belongs to a predetermined time zone at midnight. Note that this condition is not particularly limited and can be set as appropriate. For example, it may be set in consideration of the season, date and time, the presence or absence of events in the vicinity, etc., based on the actual gas use data in the past.

[0036] When it is determined in step S3 that the conditions are satisfied, the control device 20 starts executing the correction process (step S4). That is, the control device 20 closes the flow path 13 with the shut-off valve 4 for a predetermined first period T1 (step S5). During this first period T1, the control device 20 executes signal acquisition processing and flow rate calculation processing to calculate the gas flow rate Q, and further calculates the average value Qave2 at a predetermined second period T2 for the calculated gas flow rate Q (step S6). Then, the control device 20 corrects the zero reference value stored in the storage device 21 based on this average value Qave2 (step S7). Note that the second period T2 can be set to any time equal to or less than the first period T1. Also, the average value is typically an arithmetic average value, but other average values such as a moving average value may be used (the same applies in Embodiment 2).

[0037] Thereby, since the zero reference value can be corrected based on the gas flow rate acquired in a situation where there is no gas usage, the zero reference value can be corrected with high accuracy. Also, since the correction is performed using the average value Qave2 of the flow rate, the zero reference value can be corrected with better accuracy.

[0038] Note that the specific method of correcting the zero reference value by the average value Qave2 is not particularly limited. For example, the theoretical (design) propagation time difference corresponding to the flow rate Qave2 may be subtracted from the existing zero reference value (propagation time difference Δt when the flow rate is zero). Also, instead of the propagation time difference Δt, the theoretical (design) flow rate corresponding to the propagation time difference Δt may be adopted as the zero reference value. In this case, in the correction of the zero reference value (S7), the average value Qave acquired in step S6 can be directly subtracted from the zero reference value.

[0039] (Modification 1) The gas flow rate measuring device according to Modification 1 further includes a notification device for notifying the outside in the gas flow rate measuring device of Embodiment 1. When the conditions are satisfied, the control device calculates the average value of the gas flow rate calculated by the flow rate calculation process in a predetermined third period before the closing of the flow path by the shut-off valve, and if there is a predetermined difference between the average value in the second period after the closing and the average value in the third period before the closing, it executes a notification process of notifying the outside by the notification device.

[0040] Further, the gas flow rate measuring system according to Modification 1 includes a flow path main body forming a flow path, a measuring device provided in the flow path main body for measuring a physical quantity having a correlation with the gas flow rate and outputting a signal, and the above-described gas flow rate measuring device.

[0041] In addition, the configurations other than the above of the gas flow rate measuring device and the gas flow rate measuring system described below are arbitrary configurations in this modification and are not essential.

[0042] FIG. 3 is a schematic diagram of a gas flow rate measuring system 1 including the gas flow rate measuring device 2 according to Modification 1. The gas flow rate measuring system 1 according to Modification 1 is different from the gas flow rate measuring system 1 described in Embodiment 1 in that a notification device 23 and a notification unit 33 are added, and the other configurations are the same. Therefore, the differences from Embodiment 1 will be described below.

[0043] As shown in FIG. 3, the gas flow rate measuring device 2 according to Modification 1 includes a notification device 23. The notification device 23 is composed of, for example, a display device such as a liquid crystal display, a voice output device having a speaker, and the like. The notification device 23 is connected to the control device 20 via the communication device 22, and can output information that can be perceived by the user to the outside based on a control signal from the control device 20.

[0044] In addition, the control device 20 of the gas flow rate measuring device 2 includes a notification unit 33. The notification unit 33 mainly executes the following predetermined notification process to detect gas leakage and notify the outside. That is, the control device 20 determines whether or not it satisfies a predetermined condition for starting a correction measure (see step S3 in FIG. 2). When this condition is satisfied (S3: YES), before the shut-off valve 4 closes the flow path 13, the average value Qave3 in a predetermined third period T3 is calculated for the gas flow rate calculated by the flow rate calculation unit 31, and it is determined whether there is a predetermined non-zero difference between the average value Qave2 in the second period T2 after closing and the average value Qave3. Note that the "difference" serving as the determination criterion can be set as appropriate and is stored in the storage device 21.

[0045] As a result, when there is a predetermined difference between the two average values Qave2 and Qave3, the notification unit 33 causes the notification device 23 to output predetermined alarm information, assuming that gas leakage may have occurred on the downstream side of the shut-off valve 4. On the other hand, when there is no predetermined difference between the two average values Qave2 and Qave3, the process from step S4 in FIG. 2 is executed to start the correction process without outputting alarm information by the notification device 23.

[0046] According to the gas flow rate measuring system 1 and the gas flow rate measuring device 2 of such a modification 1, when the condition for estimating that there is no gas use downstream of the own device (gas flow rate measuring device 2) is satisfied, the presence or absence of gas leakage can be determined, so that highly accurate determination can be realized. In addition, since the correction process is executed when there is no predetermined difference (that is, the difference is small) in the average values of the gas flow rates before and after closing the shut-off valve 4, the correction of the zero reference value can also be performed with high accuracy. Note that the notification device 23 may be a communication interface connectable to an external communication network, or may be configured to transmit alarm information to a gas flow rate management server or the like via the network.

[0047] (Modification 2) The gas flow rate measuring device according to Modification 2 further includes a pressure sensor that measures the pressure of the gas in the flow path in the gas flow rate measuring device of Embodiment 1. When the pressure of the gas measured by the pressure sensor drops below a predetermined value during the period in which the control device closes the flow path with a shut-off valve for executing the correction process, the control device executes an interruption process of interrupting the correction process and opening the flow path.

[0048] Further, the gas flow rate measuring system according to Modification 2 includes a flow path main body that forms a flow path, a measuring device that is provided in the flow path main body and measures a physical quantity having a correlation with the flow rate of the gas and outputs a signal, and the above-described gas flow rate measuring device.

[0049] Note that the configurations of the gas flow rate measuring device and the gas flow rate measuring system other than those described below are arbitrary configurations in this modification and are not essential.

[0050] FIG. 4 is a schematic diagram of a gas flow rate measuring system 1 including a gas flow rate measuring device 2 according to Modification 2. The gas flow rate measuring system 1 of Modification 2 is different from the gas flow rate measuring system 1 described in Embodiment 1 in that a pressure sensor 24 and an interruption unit 34 are added, and the other configurations are the same. Therefore, the differences from Embodiment 1 will be described below.

[0051] As shown in FIG. 4, the gas flow rate measuring device 2 of Modification 2 includes a pressure sensor 24. The pressure sensor 24 is composed of a diaphragm and a strain gauge, or other known devices that can output a signal corresponding to the pressure of the gas. The pressure sensor 24 is provided, for example, on the wall portion of the flow path main body 10 and is connected to the control device 20 via the communication device 22. Therefore, the pressure sensor 24 can detect the pressure of the gas flowing through the flow path 13, and the detected pressure value is transmitted to the control device 20 as an electrical signal.

[0052] Further, the control device 20 of the gas flow rate measuring device 2 is provided with an interrupt section 34. When the interrupt section 34 detects gas usage downstream mainly during the execution of the correction process (while the flow path 13 is closed), it executes the following predetermined interrupt process to interrupt the correction process. That is, as described with reference to FIG. 2, when the control device 20 starts the correction process (S4) when a predetermined condition is satisfied (S3: YES), it closes the flow path 13 by the shut-off valve 4 for a predetermined first period T1 (S5), and executes a process for correcting the zero reference value (S6, S7).

[0053] On the other hand, the control device 20 receives a signal from the pressure sensor 24 and monitors the gas pressure in parallel with the operation of FIG. 2. Then, after the start of the correction process, it determines whether or not the gas pressure has dropped by a predetermined value or more. As a result, if the gas pressure has not dropped by a predetermined value or more, the execution of the correction process is continued. On the other hand, if the gas pressure has dropped by a predetermined value or more, the correction process is interrupted and the flow path 13 is opened by the shut-off valve 4.

[0054] According to such a gas flow rate measurement system 1 and gas flow rate measuring device 2 of Modification 2, even after the start of the correction process, it is possible to detect by the change in the gas pressure that the user has started using gas downstream. Therefore, when the user starts using gas, the ongoing correction process can be interrupted, the flow path 13 can be opened, and it is possible to prevent any hindrance to the user's gas usage.

[0055] (Modification 3) For Embodiment 1, the configurations of both Modification 1 and Modification 2 may be applied. FIG. 5 is a schematic diagram of a gas flow rate measurement system 1 including the gas flow rate measuring device 2 according to Modification 3, showing a configuration in which an alarm device 23 and a pressure sensor 24 are added to the configuration of Embodiment 1, and an alarm section 33 and an interrupt section 34 are also added to the control device 20.

[0056] According to the gas flow measurement system 1 and the gas flow measurement device 2 of such a modification 3, the correction process described in the first embodiment can be executed, and the notification process described in the first modification and the interruption process described in the second modification can also be executed. Therefore, the zero reference value can be accurately corrected, the possibility of gas leakage can be detected and notified to the outside, and further, when the use of gas by the user is detected during the correction process, the correction process can be interrupted.

[0057] (Second Embodiment) The gas flow measurement device according to the first embodiment includes a storage unit that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in the flow path, and a control device, and is a gas flow measurement device that measures the flow rate of gas in the flow path. The control device executes a signal acquisition process for acquiring a correlation value, a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, calculates an average value of the flow rate of gas calculated by the flow rate calculation process in a predetermined fourth period, and when the average value is equal to or less than a predetermined value, corrects the reference correlation value stored in the storage device with the average value.

[0058] In addition, the gas flow measurement system according to the second embodiment includes a flow path main body that forms a flow path, a measurement device that is provided in the flow path main body, measures a physical quantity having a correlation with the flow rate of gas, and outputs a signal, and the above-described gas flow measurement device.

[0059] Note that the configurations of the gas flow measurement device and the gas flow measurement system other than those described above are arbitrary configurations and are not essential in this embodiment. Also, hereinafter, the same or corresponding elements throughout all the drawings will be given the same reference numerals, and redundant descriptions will be omitted.

[0060] FIG. 6 is a schematic diagram of a gas flow measurement system 1A including a gas flow measurement device 2A according to the second embodiment. The gas flow measurement system 1A includes the gas flow measurement device 2A and a flow path unit 3. The flow path unit 3 of the second embodiment can adopt the same configuration as the flow path unit 3 described in the first embodiment.

[0061] The gas flow rate measuring device 2A is configured as a computer system having one or more processors, memories, and communication interfaces respectively in terms of hardware. Further, in terms of the functional configuration, the gas flow rate measuring device 2A includes a control device 20, a storage device 21, and a communication device 22.

[0062] The control device 20 is composed of a processor and an internal memory, etc., and controls the operations of each part of the gas flow rate measuring device 2A based on a computer program and data stored in the storage device 21 which is an internal memory or an external memory. For example, the control device 20 functions as at least a signal acquisition unit 30, a flow rate calculation unit 31, and a correction unit 32A.

[0063] Here, the correction unit 32A corrects the zero reference value as follows. That is, the control device 20 functioning as the correction unit 32A calculates the average value Qave4 of the gas flow rate Q calculated by the flow rate calculation unit 31 in a predetermined fourth period T4. Then, it is determined whether or not this average value Qave4 is less than or equal to a predetermined value. As a result, when the average value Qave4 is greater than the predetermined value, the zero reference value is not corrected, and when it is less than or equal to the predetermined value, the zero reference value (reference correlation value) stored in the storage device 21 is corrected by the average value Qave4. Note that the predetermined value for comparison with the average value Qave4 can be arbitrarily set and is stored in the storage device 21, and is, for example, 3 L / h or the like.

[0064] Thereby, it is possible to determine the timing when it can be inferred that there is no use of gas downstream of the own device due to the gas flow rate, and at that timing, the zero reference value can be corrected. Therefore, the correction process can be executed not only at fixed timings such as at night, but also at any timing when it can be inferred that there is no use of gas.

[0065] Further, the following techniques are disclosed by the description of the above embodiments.

[0066] (Technology 1) The gas flow rate measuring device of Technology 1 includes a storage device that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in a flow path, and a control device, and is a gas flow rate measuring device that measures the flow rate of gas in the flow path that can be opened and closed by a shut-off valve. The control device performs a signal acquisition process for acquiring the correlation value, a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, and when a preset condition that gas use downstream of the device itself is presumed not to occur is satisfied, closes the flow path by the shut-off valve for a predetermined first period, and during the first period, calculates an average value in a predetermined second period for the flow rate of gas calculated by the flow rate calculation process, and performs a correction process for correcting the reference correlation value stored in the storage device based on the average value.

[0067] As a result, the reference correlation value (e.g., zero reference value) can be corrected based on the gas flow rate acquired in a situation where there is no gas use, so that the reference correlation value can be accurately corrected. In addition, since the correction is performed using the average value of the flow rate, the zero reference value can be corrected with better accuracy. As a result, the measurement error that occurs after the start of operation at the site can be eliminated, and the measurement accuracy can be improved.

[0068] (Technology 2) The gas flow rate measuring device of Technology 2 further includes a notification device for notifying the outside in Technology 1. When the control device satisfies the condition, before closing the flow path by the shut-off valve, it calculates an average value in a predetermined third period for the flow rate of gas calculated by the flow rate calculation process, and when there is a predetermined difference between the average value in the second period after closing and the average value in the third period before closing, it performs a notification process for notifying the outside by the notification device.

[0069] As a result, it is also possible to determine the presence or absence of gas leakage when performing the correction process.

[0070] (Technology 3) The gas flow rate measuring device of Technology 3 further includes a pressure sensor that measures the pressure of the gas in the flow path in Technology 1 or 2. During the period when the control device closes the flow path with the shut-off valve for executing the correction process, if the pressure of the gas measured by the pressure sensor drops by a predetermined value or more, the control device executes an interruption process of interrupting the correction process and opening the flow path.

[0071] Thereby, when gas is used downstream of the own device during the execution of the correction process involving closing of the flow path, by interrupting the correction process and opening the flow path, it is possible to avoid causing an obstacle to the use of gas by the user.

[0072] (Technology 4) The gas flow rate measuring device of Technology 4 includes a storage unit that stores a reference correlation value which is a value corresponding to a predetermined flow rate for a correlation value having a correlation with the flow rate of the gas in the flow path, and a control device. The gas flow rate measuring device measures the flow rate of the gas in the flow path. The control device executes a signal acquisition process for acquiring the correlation value, a flow rate calculation process for calculating the flow rate of the gas based on the acquired correlation value, calculates an average value in a predetermined fourth period for the flow rate of the gas calculated by the flow rate calculation process, and executes a correction process of correcting the reference correlation value stored in the storage device with the average value when the average value is equal to or less than a predetermined value.

[0073] Thereby, the correction process can be executed at a timing when it can be inferred that there is no gas use downstream of the own device, even if it is not a predetermined timing. As a result, measurement errors occurring after the start of operation at the site can be eliminated, and the measurement accuracy can be improved.

[0074] (Technology 5) The gas flow rate measurement system of Technology 5 includes a flow path main body that forms a flow path, a measurement device that is provided on the flow path main body, measures a physical quantity having a correlation with the flow rate of the gas, and outputs a signal, and the gas flow rate measurement device according to any one of Technologies 1 to 4.

[0075] This can eliminate measurement errors that occur after the gas flow measurement device is installed at the site and operation is started, and can improve the measurement accuracy.

Industrial Applicability

[0076] The present disclosure can be applied to a gas flow measurement device and a gas flow measurement system for measuring the flow rate of a gas.

Explanation of Reference Numerals

[0077] 1, 1A Gas flow measurement system 2, 2A Gas flow measurement device 3 Flow path unit 10 Flow path body 13 Flow path 20 Control device 21 Storage device 23 Notification device 24 Pressure sensor 100 Gas pipe

Claims

1. A gas flow measurement device comprising a storage device that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in a flow path, and a control device, and measuring the flow rate of gas in the flow path that can be opened and closed by a shut-off valve, wherein the control device performs a signal acquisition process for acquiring the correlation value, performs a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, when a preset condition that gas use downstream of the own device is not estimated to occur is satisfied, closes the flow path by the shut-off valve for a predetermined first period, and during the first period, calculates an average value in a predetermined second period for the flow rate of gas calculated by the flow rate calculation process, and corrects the reference correlation value stored in the storage device based on the average value, and executes a correction process, a gas flow measurement device.

2. further comprising a notification device for notifying the outside, wherein the control device, when the condition is satisfied, calculates an average value in a predetermined third period for the flow rate of gas calculated by the flow rate calculation process before closing the flow path by the shut-off valve, and when there is a predetermined difference between the average value in the second period after closing and the average value in the third period before closing, executes a notification process for notifying the outside by the notification device, the gas flow measurement device according to claim 1.

3. further comprising a pressure sensor for measuring the pressure of gas in the flow path, wherein the control device, when the pressure of gas measured by the pressure sensor drops below a predetermined value during the period when the flow path is closed by the shut-off valve for executing the correction process, interrupts the correction process and executes an interruption process for opening the flow path, the gas flow measurement device according to claim 1.

4. A gas flow measurement device comprising a storage unit that stores a reference correlation value, which is a value corresponding to a predetermined flow rate, for a correlation value having a correlation with the flow rate of gas in a flow path, and a control device, and measuring the flow rate of gas in the flow path, wherein the control device performs a signal acquisition process for acquiring the correlation value, performs a flow rate calculation process for calculating the flow rate of gas based on the acquired correlation value, calculates an average value in a predetermined fourth period for the flow rate of gas calculated by the flow rate calculation process, and when the average value is equal to or less than a predetermined value, corrects the reference correlation value stored in the storage device with the average value, and executes a correction process, a gas flow measurement device.

5. a flow path main body forming a flow path, A measuring device provided in the flow path body, which measures a physical quantity having a correlation with the flow rate of the gas and outputs a signal; A gas flow rate measuring device according to any one of claims 1 to 4; and A gas flow rate measuring system.

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