JP2023101797A - gas safety device - Google Patents

Abstract

To improve measurement accuracy of gas supply pressure in a gas safety device capable of measuring the gas supply pressure.SOLUTION: The gas safety device includes: a flow passage 101; a flow rate measurement portion 103 that measures a flow rate of gas flowing through the flow passage 101; a gas-side absolute pressure sensor 105 that measures absolute pressure of the gas; an atmosphere-side absolute pressure sensor 106 that measures absolute pressure of atmospheric pressure; differential pressure value collection means 201 that collects n differential values of pressure values measured at the same timing by the gas-side absolute pressure sensor 105 and the atmosphere-side absolute pressure sensor 106 in a predetermined measurement time; gas pressure determination means 209 that calculates gas supply pressure from an average value of n differential pressure values collected by the differential pressure value collection means 201; a shutoff valve 102 that shuts off the flow passage 101; and a control circuit 204 that controls the flow rate measurement portion 103 and that, if it is determined that the flow rate measured by the flow rate measurement portion 103 or a pressure change measured by the gas pressure determination means 209 is abnormal, shuts off the flow passage 101 with the shutoff valve 102.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a gas safety device that measures a gas flow rate and shuts off a gas passage when an abnormal flow rate is measured to ensure safety in using gas.

Patent Literature 1 discloses a gas safety device in which a gas meter that measures the amount of gas used determines that there is an abnormality and shuts off the gas passage to ensure safety. This gas safety device includes an ultrasonic flow rate measuring unit that integrates an ultrasonic sensor and a circuit board on which an ultrasonic sensor drive circuit is configured, a pressure sensor that measures the differential pressure between the supply pressure side and the atmospheric pressure, a control function that shuts off the flow path to stop the gas supply when the pressure measured by the pressure sensor is determined to be abnormal, and a notification function.

JP 2014-98563 A

Since the pressure sensor built into the gas safety device is a differential pressure measurement type that measures the gas pressure based on the atmospheric pressure, it has a through hole through which the gas is introduced into the pressure sensor. When the temperature around the gas safety device becomes extremely high due to a fire in the surrounding area, the gas may leak from the through hole and cause secondary damage such as a gas explosion due to deformation or burning of the pressure sensor. Therefore, as a configuration that does not require a through hole, there is a means for measuring the change in gas supply pressure from the difference between the measured values of an absolute pressure sensor that measures atmospheric pressure and an absolute pressure sensor that measures gas pressure.

However, there is a problem that the measurement accuracy is lowered due to individual variations of the two sensors and measurement timing errors.

A gas safety device according to the present disclosure includes a flow path for causing a gas to flow, a flow rate measuring unit for measuring the flow rate of the gas flowing through the flow path, a first pressure sensor disposed inside the flow path for measuring the absolute pressure of the gas, a second pressure sensor disposed outside the flow path for measuring the absolute pressure of the atmospheric pressure, and a differential pressure value between the pressure value measured by the first pressure sensor and the pressure value measured by the second pressure sensor at the same timing as the measurement by the first pressure sensor. a gas pressure determination means for calculating a gas supply pressure based on an average value of the n differential pressure values sampled by the differential pressure value sampling means; a shutoff valve for shutting off the flow path;

INDUSTRIAL APPLICABILITY According to the present disclosure, a gas supply pressure can be accurately measured in a gas safety device that does not blow out gas even when the temperature around the gas safety device becomes high.

Configuration diagram of gas safety device in Embodiment 1 Operation explanatory diagram in Embodiment 1 Configuration diagram of a gas safety device according to Embodiment 2 Operation explanatory diagram in Embodiment 2 Configuration diagram of a gas safety device according to Embodiment 3 Operation explanatory diagram in Embodiment 3 Configuration diagram of a gas safety device according to Embodiment 4 Operation explanatory diagram in Embodiment 4

A first aspect of the invention comprises a flow path for causing a gas to flow, a flow rate measuring section for measuring the flow rate of the gas flowing through the flow path, a first pressure sensor disposed inside the flow path for measuring the absolute pressure of the gas, a second pressure sensor disposed outside the flow path for measuring the absolute pressure of the atmospheric pressure, a pressure value sampling means for sampling n pressure values measured by the first pressure sensor and m pressure values measured by the second pressure sensor, and the pressure value sampling means. a gas pressure determination means for calculating the gas supply pressure from the difference between the average values of the respective pressure values; a shutoff valve for shutting off the flow path; and a controller for controlling the flow rate measurement unit and shutting off the flow path with the shutoff valve when the flow rate measured by the flow rate measurement unit or the gas supply pressure calculated by the gas pressure determination means is determined to be abnormal. This eliminates the need for a through hole that is required when using a differential pressure measurement type pressure sensor, and prevents gas from blowing out even when the temperature around the gas safety device becomes high due to a fire or the like, and realizes a gas safety device with higher safety.

A second aspect of the present invention comprises a flow path for causing a gas to flow, a flow rate measuring section for measuring the flow rate of the gas flowing through the flow path, a first pressure sensor disposed inside the flow path for measuring the absolute pressure of the gas, a second pressure sensor disposed outside the flow path for measuring the absolute pressure of the atmospheric pressure, and a pressure value measured by the first pressure sensor and a pressure value measured by the second pressure sensor at the same timing as the measurement by the first pressure sensor, and sampling n differential pressure values between the pressure value measured by the first pressure sensor and the pressure value measured by the second pressure sensor at the same timing of the measurement by the first pressure sensor. a pressure value collecting means; a gas pressure determining means for calculating a gas supply pressure based on an average value of n differential pressure values collected by the differential pressure value collecting means; a shutoff valve for shutting off the flow path; It is possible to improve the measurement accuracy due to individual variations and measurement timing errors, eliminate the need for through holes that are required when using a differential pressure measurement type pressure sensor, and prevent gas from blowing out even when the surroundings of the gas safety device become hot due to fire, etc., and realize a more safe gas safety device.

In a third invention, particularly in the first invention, an average value comparison means is provided for comparing the pressure values of the first pressure sensor and the second pressure sensor collected by the pressure value collection means with the average value, and the gas pressure determination means calculates the average value by excluding the pressure value determined to be clearly different from the average value by the average value comparison means, thereby detecting the gas supply pressure using the average value of the two absolute pressure sensors. It is possible to improve measurement accuracy due to timing errors, eliminate the need for a through hole that is required when using a differential pressure measurement type pressure sensor, prevent gas from blowing out even if the surroundings of the gas safety device become hot due to a fire or the like, and realize a gas safety device with higher safety.

In a fourth aspect of the invention, particularly in the second aspect, the differential pressure value comparing means compares the differential pressure values collected by the differential pressure value collecting means, and the gas pressure determining means detects the gas supply pressure using the average value of the two absolute pressure sensors by calculating the average value by excluding the differential pressure values determined by the differential pressure value comparing means to be clearly different from other differential pressure values. A through-hole required when using a pressure sensor of the type is not necessary, and even if the surroundings of the gas safety device become hot due to a fire or the like, the gas can be prevented from blowing out, and a safer gas safety device can be realized.

In a fifth invention, particularly in any one of the first to fourth inventions, the flow rate measurement unit has a measurement circuit arranged inside the flow path, the first pressure sensor is arranged on the measurement circuit, the control circuit is arranged outside the flow path, and the second pressure sensor is arranged on the control circuit.

In a sixth invention, particularly in any one of the first to fifth inventions, the flow rate measurement unit includes an ultrasonic flow rate measurement unit that integrates an ultrasonic sensor and a measurement circuit that drives the ultrasonic sensor and measures the flow rate, the ultrasonic flow rate measurement unit is installed in a gas atmosphere, the ultrasonic flow rate measurement unit is provided with the first pressure sensor, and the control circuit controls the ultrasonic flow rate measurement unit, thereby also controlling the first pressure sensor on the ultrasonic sensor drive circuit.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted.

(Embodiment 1)
Embodiment 1 will be described below with reference to FIGS. 1 and 2. FIG.

1, the gas safety device 100 includes a flow path 101, a shutoff valve 102, a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101, a control circuit 104 that integrates the amount of gas used using flow measurement data measured by the flow rate measurement unit 103, a gas side absolute pressure sensor 105 that measures the gas side that can measure the absolute pressure, an atmosphere side absolute pressure sensor 106 that measures the atmosphere side, an electronic circuit 107 installed in the gas atmosphere, and a predetermined measurement time. , a pressure value collecting means 108 for collecting a predetermined number of pressure values measured by the gas side absolute pressure sensor 105 and the atmosphere side absolute pressure sensor 106, respectively, and a gas pressure determination means 109 for calculating the average value of the respective pressure values collected by the pressure value collecting means 108 and calculating the gas supply pressure from the difference.

The gas-side absolute pressure sensor 105 is mounted as an electronic component on an electronic circuit 107 installed in the gas atmosphere in the flow path 101, and measures the absolute pressure of the gas in the flow path 101 with a signal from the control circuit 104. Also, the atmosphere-side absolute pressure sensor 106 is mounted as an electronic component on the control circuit 104 installed on the atmosphere side outside the flow path 101, and measures the atmosphere-side absolute pressure with a signal from the control circuit 104.

Next, using FIG. 2, a specific description of the operation will be given. Pressure measurement by the gas pressure determination means 109 is periodically performed at predetermined time intervals T (for example, 2 to 10 seconds). In FIG. 2, pressure measurement times T1 and T2 indicate pressure measurement timings. At pressure measurement time T1, the pressure value sampling means 108 samples n absolute pressures on the gas side and m absolute pressures on the atmosphere side.

That is, during the pressure measurement time T1, the gas-side absolute pressure sensor 105 measures pressure values Pg(1), Pg(2), . ), a total of m (for example, 32) pressure values are measured and collected by the pressure value collecting means 108 .

Then, the gas pressure determination means 109 calculates the difference (Pg-Pa) between the gas side pressure value Pg obtained by averaging n gas side pressure values and the atmosphere side pressure value Pa obtained by averaging m atmospheric side pressure values (Pg-Pa) as the gas supply pressure.

The control circuit 104 determines the flow rate measurement data measured by the flow rate measurement unit 103, the gas supply pressure calculated by the gas pressure determination means 109, and its change, and determines whether there is an abnormality such as a gas leak.

As described above, in the present embodiment, since the average value of n and m absolute pressure sensors capable of measuring absolute pressure is used to detect fluctuations in gas supply pressure, measurement accuracy due to individual variations in the two sensors and errors in measurement timing can be improved.

In the present embodiment, the configuration using the average value has been described, but it goes without saying that the median value can be used instead of the average value to achieve the same result.

Needless to say, in the present embodiment, even if the flow rate measurement section is used as an ultrasonic flow rate measurement, the same effect can be achieved.

In the present embodiment, the number (n) of pressure values measured on the gas side and the number (m) of pressure values measured on the atmosphere side are the same, 32. However, the numbers may be different depending on the measurement environment, such as the influence of pressure fluctuations and noise. Alternatively, the number of measurements on the atmosphere side (m), which is expected to fluctuate less, may be smaller than the number of measurements on the gas side (n). In this case, the power consumption of the atmosphere-side absolute pressure sensor 106 can be reduced.

In this embodiment, the gas-side absolute pressure sensor 105 is mounted on the electronic circuit 107 installed in the gas atmosphere in the flow path 101, but it goes without saying that it may be mounted anywhere in the flow path. Further, although the configuration in which the atmospheric pressure absolute pressure sensor 106 is mounted on the control circuit 104 installed on the atmospheric side outside the flow path 101 has been described, there is no limit to the mounting location as long as the atmospheric pressure can be measured.

(Embodiment 2)
Embodiment 2 will be described below with reference to FIGS. 3 and 4. FIG. 3, the same functions as those described in FIG. 1 are denoted by the same reference numerals.

The gas safety device 200 includes a flow path 101, a shutoff valve 102, a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101, a control circuit 204 that integrates the amount of gas used using the flow rate measurement data measured by the flow rate measurement unit 103, a gas side absolute pressure sensor 105 that measures the gas side that can measure the absolute pressure, an atmosphere side absolute pressure sensor 106 that measures the atmosphere side, an electronic circuit 107 installed in the gas atmosphere, and a gas side absolute pressure sensor 106 that measures the atmosphere side. Differential pressure value sampling means 201 for sampling n differential pressure values measured at the same timing by the side absolute pressure sensor 105 and the atmosphere side absolute pressure sensor 106, and gas pressure determination means 209 for calculating the gas supply pressure from the average value of the n differential pressure values sampled by the differential pressure value sampling means 201.

A specific description of the operation will be given with reference to FIG. The same functions as those described in FIG. 2 are denoted by the same reference numerals.

Pressure measurement by the gas pressure determination means 209 is periodically performed at predetermined time intervals T (for example, 2 to 10 seconds). In FIG. 4, pressure measurement times T1 and T2 indicate pressure measurement timings. At pressure measurement time T1, the differential pressure value sampling means 201 samples n differential pressure values between the absolute pressure of the gas and the absolute pressure of the atmosphere.

The difference from the first embodiment is that the pressure value sampling means 108 acquires n differences between the gas pressure and the atmospheric pressure measured at the same timing by the gas side absolute pressure sensors 105 and 106 .

That is, during the pressure measurement time T1, the gas-side absolute pressure sensor 105 measures pressure values Pg(1), Pg(2), . ) are measured, and the difference values ΔP(1)=Pg(1)-Pa(1), ΔP(2)=Pg(2)-Pa(2), .

Then, the gas pressure determining means 209 calculates the gas supply pressure by averaging the n difference values.

The control circuit 204 determines the flow rate measurement data measured by the flow rate measurement unit 103, the gas supply pressure calculated by the gas pressure determination means 209, and its change, and determines whether there is an abnormality such as gas leakage.

As described above, in the present embodiment, since the average value of the difference between the pressure values measured at the same timing by two absolute pressure sensors capable of measuring absolute pressure is used to detect fluctuations in the gas supply pressure, it is possible to improve measurement accuracy due to individual variations in the two sensors and errors in measurement timing.

In the present embodiment, the configuration using the average value has been described, but it goes without saying that the median value can be used instead of the average value to achieve the same result.

(Embodiment 3)
The third embodiment will be described below with reference to FIGS. 5 and 6. FIG. 5, the same functions as those described in FIG. 1 are denoted by the same reference numerals.

The gas safety device 300 includes a flow path 101, a shutoff valve 102, a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101, a control circuit 304 that integrates the amount of gas used using the flow measurement data measured by the flow rate measurement unit 103, a gas side absolute pressure sensor 105 that measures the gas side that can measure the absolute pressure, an atmosphere side absolute pressure sensor 106 that measures the atmosphere side, an electronic circuit 107 installed in the gas atmosphere, and a gas side absolute pressure sensor 106 that measures the atmosphere side. Pressure value sampling means 108 for sampling a predetermined number of pressures measured by the side absolute pressure sensor 105 and the atmosphere side absolute pressure sensor 106 , pressure value comparing means 301 , abnormal value ignoring means 302 , and gas pressure determining means 309 .

Here, the pressure value comparing means 301 compares the respective pressure values obtained by the pressure value collecting means 108 . Abnormal value ignoring means 302 judges a value that is clearly different from other pressure values in pressure value comparing means 301 (for example, compares three consecutive measured values of pressure, and judges abnormal if one of them has a difference of 1000 pascals or more from other measured values, or a difference of a predetermined percentage or more from the overall average) as an abnormal value, and outputs the pressure value excluding this abnormal value to gas pressure judgment means 309. The gas pressure determination means 309 calculates the average values of the gas side pressure values and the atmosphere side pressure values output from the abnormal value ignoring means 302, and calculates the difference between the average values as the gas supply pressure.

Next, using FIG. 6, a specific description of the operation will be given. The same functions as those described in FIGS. 2 and 5 are denoted by the same reference numerals.

Pressure measurement by the gas pressure determination means 309 is periodically performed at predetermined time intervals T (for example, 2 to 10 seconds). In FIG. 6, pressure measurement times T1 and T2 indicate the timing of pressure measurement. At pressure measurement time T1, n absolute gas pressures and n absolute atmospheric pressures are measured by the pressure value sampling means 108 and sampled by the pressure value sampling means 108.

That is, during the pressure measurement time T1, the gas-side absolute pressure sensor 105 measures pressure values Pg(1), Pg(2), . m), a total of m (for example, 32) pressure values are measured.

Then, for example, when the second gas-side pressure value Pg(2) is clearly different from other measured values, the pressure value comparing means 301 compares it with other values and determines that it is an abnormal value. During the gas-side pressure measurement time T1, the abnormal value ignoring means 302 outputs n-1 pressure values excluding the second pressure value Pg(2) to the gas pressure determining means 109, and the gas-side pressure value Pg is averaged. On the other hand, when there is no abnormal pressure value on the atmosphere side, m pressure values are output to the gas pressure determination means 109, and the atmosphere side pressure value Pa is calculated by averaging them.

Then, the gas pressure determination means 109 calculates the difference (Pg−Pa) between the gas side pressure value Pg obtained by averaging n−1 pressure values excluding the abnormal pressure value Pg(2) and the atmosphere side pressure value Pa obtained by averaging m absolute pressure values of the atmosphere side (Pg−Pa) as the gas supply pressure.

The control circuit 304 determines the flow rate measurement data measured by the flow rate measurement unit 103, the gas supply pressure calculated by the gas pressure determination means 109, and its change, and determines whether there is an abnormality such as gas leakage.

As described above, in the present embodiment, when two absolute pressure sensors capable of measuring absolute pressure are used to detect fluctuations in the gas supply pressure, by excluding abnormal measurement values, measurement accuracy due to individual variations in the two sensors and errors in measurement timing can be improved.

(Embodiment 4)
Embodiment 4 will be described below with reference to FIGS. 7 and 8. FIG. In FIG. 7, the same functions as those described in FIGS. 1 and 3 are denoted by the same numbers.

The gas safety device 400 includes a flow path 101, a shutoff valve 102, a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101, a control circuit 404 that integrates the amount of gas used using the flow measurement data measured by the flow rate measurement unit 103, a gas side absolute pressure sensor 105 that measures the gas side that can measure the absolute pressure, an atmosphere side absolute pressure sensor 106 that measures the atmosphere side, an electronic circuit 107 installed in the gas atmosphere, and a gas side absolute pressure sensor 106 that measures the atmosphere side. It consists of a differential pressure value sampling means 201 for sampling n differences in pressure values measured at the same timing by the side absolute pressure sensor 105 and the atmosphere side absolute pressure sensor 106, a differential pressure value comparing means 401, a differential pressure abnormal value ignoring means 402, and a gas pressure determining means 409.

Here, the differential pressure value comparison means 401 compares each of the n differential pressure values obtained by the differential pressure value sampling means 201 . Differentated abnormal value ignoring means 402 is clearly different from other differentiated values in differential comparative means 401 (for example, comparing three consecutive pressure measurements, one has a difference of more than 1000 pascal, or a specified percentage of the overall average, so it is abnormal. The value determined as an abnormal value is determined as an abnormal value, and the differential pressure value of N -1 except this abnormal value is output to the gas pressure judgment method 409.

The gas pressure determining means 409 calculates the average value of the n−1 differential pressure values output from the differential pressure value comparing means 401 to calculate the gas supply pressure.

Next, using FIG. 8, a specific description of the operation will be given. The same functions as those described in FIGS. 2, 4 and 7 are denoted by the same numbers.

Pressure measurement by the gas pressure determination means 209 is periodically performed at predetermined time intervals T (for example, 2 to 10 seconds). In FIG. 8, pressure measurement times T1 and T2 indicate pressure measurement timings. At pressure measurement time T1, the differential pressure value sampling means 201 samples n differential pressure values between the absolute pressure of the gas and the absolute pressure of the atmosphere.

That is, during the pressure measurement time T1, the gas-side absolute pressure sensor 105 measures pressure values Pg(1), Pg(2), . ) are measured, and the difference values ΔP(1)=Pg(1)-Pa(1), ΔP(2)=Pg(2)-Pa(2), .

Here, for example, when the second pressure value Pg(2) on the gas side is clearly different from the other measured values, the differential pressure value ΔP(2) calculated from Pg(2) and Pa(2) is compared with other values by the differential pressure value comparison means 401 and judged to be an abnormal value. 9, and the average value of n-1 times of differential pressure measurements is calculated as the gas supply pressure.

Then, the gas pressure determination means 409 calculates the gas supply pressure by averaging n−1 differential pressure values excluding the abnormal value ΔP(2) outputted from the differential pressure abnormal value ignoring means 402 .

The control circuit 404 determines the flow rate measurement data measured by the flow rate measurement unit 103, the gas supply pressure calculated by the gas pressure determination means 409, and its change, and determines whether there is an abnormality such as a gas leak.

As described above, in the present embodiment, two absolute pressure sensors capable of measuring absolute pressure are used, and out of the differential pressure values of the pressure values measured at the same timing, the gas supply pressure is calculated by excluding abnormal measured values. By accurately detecting fluctuations in the gas supply pressure, measurement accuracy due to individual variations of the two sensors and errors in measurement timing can be improved. It is possible to prevent gas from coming out, and a safer gas safety device can be realized.

According to the present disclosure, the gas safety device can prevent gas from blowing out from the through-hole for the pressure sensor even when the temperature around the gas safety device becomes high due to a fire or the like, so not only can the safety be improved, but the gas safety device can be realized at a lower cost, and can be applied to applications such as general household and commercial gas meters.

Reference Signs List 100, 200, 300, 400 Gas safety device 101 Flow path 102 Shutoff valve 103 Flow measurement unit 104, 204, 304, 404 Control circuit 105 Gas side absolute pressure sensor (first pressure sensor)
106 atmosphere side absolute pressure sensor (second pressure sensor)
107 electronic circuit (measurement circuit)
108 pressure value collecting means 109, 209, 309, 409 gas pressure determining means 201 differential pressure value collecting means 301 pressure value comparing means 302 abnormal value ignoring means 401 differential pressure value comparing means 402 differential pressure abnormal value ignoring means

Claims (4)

a channel for flowing gas;
a flow rate measurement unit for measuring the flow rate of the gas flowing through the flow path;
a first pressure sensor disposed inside the flow path and measuring the absolute pressure of the gas;
a second pressure sensor positioned outside the flow path and measuring the absolute pressure of atmospheric pressure;
Differential pressure value collecting means for collecting n differential pressure values between the pressure value measured by the first pressure sensor and the pressure value measured by the second pressure sensor at the same timing of the measurement by the first pressure sensor;
gas pressure determination means for calculating a gas supply pressure based on an average value of the n differential pressure values sampled by the differential pressure value sampling means;
a shutoff valve that shuts off the flow path;
a control circuit that controls the flow rate measuring unit and shuts off the flow path with the shutoff valve when the flow rate measured by the flow rate measuring unit or the gas supply pressure calculated by the gas pressure determining means is determined to be abnormal;
Gas safety device with. differential pressure value comparing means for comparing differential pressure values collected by the differential pressure value collecting means;
2. The gas safety device according to claim 1, wherein said gas pressure determination means calculates said average value by excluding differential pressure values determined by said differential pressure value comparison means to be clearly different from other differential pressure values. The flow rate measurement unit has a measurement circuit arranged inside the flow path, the first pressure sensor is configured on the measurement circuit,
3. The gas safety device according to claim 1, wherein said control circuit is arranged outside said flow path, and said second pressure sensor is arranged on said control circuit. The flow measurement unit includes an ultrasonic flow measurement unit that integrates an ultrasonic sensor and a measurement circuit that drives the ultrasonic sensor and measures the flow rate,
The gas safety device according to any one of claims 1 to 3, wherein the ultrasonic flow rate measurement unit is installed in a gas atmosphere, the ultrasonic flow rate measurement unit is provided with the first pressure sensor, and the control circuit controls the ultrasonic flow rate measurement unit, thereby also controlling the first pressure sensor on the ultrasonic sensor drive circuit.