阅读说明：本技术 燃气安全装置 (Gas safety device ) 是由 行德太一 安田宪司 内田健太 于 2020-05-13 设计创作，主要内容包括：具备：流路(101)；切断阀(102),其用于将流路(101)切断；流量测量部(103),其测定燃气的流量；燃气侧绝压压力传感器(105),其测定燃气的绝对压力；大气侧绝压压力传感器(106),其测定大气压的绝对压力；以及压力值变动探测部(108),其探测由燃气侧绝压压力传感器(105)测量出的绝对压力的变动状态。另外,具备：传感器驱动控制部(109),其根据压力值变动探测部(108)中的压力变动的值来控制大气侧绝压压力传感器(106)的驱动；以及燃气压力判定部(110),其根据2个传感器处于驱动状态时测量出的压力值的差来计算燃气供给压力。还具备控制电路(104),在通过由流量测量部(103)测定出的流量、或由燃气压力判定部(110)计算出的燃气供给压力判定为异常的情况下,该控制电路(104)利用切断阀(102)将流路(101)切断。(The disclosed device is provided with: a flow path (101); a shut-off valve (102) for shutting off the flow path (101); a flow rate measurement unit (103) that measures the flow rate of the gas; a gas-side absolute pressure sensor (105) that measures the absolute pressure of the gas; an atmospheric-side absolute pressure sensor (106) that measures an absolute pressure of atmospheric pressure; and a pressure value fluctuation detection unit (108) that detects the fluctuation state of the absolute pressure measured by the gas-side absolute pressure sensor (105). Further, the apparatus comprises: a sensor drive control unit (109) that controls the driving of the atmospheric-side absolute pressure sensor (106) on the basis of the value of the pressure fluctuation in the pressure value fluctuation detection unit (108); and a gas pressure determination unit (110) that calculates the gas supply pressure from the difference between the pressure values measured when the 2 sensors are in the drive state. The gas pressure detection device is further provided with a control circuit (104), and when the flow rate measured by the flow rate measurement unit (103) or the gas supply pressure calculated by the gas pressure determination unit (110) determines that the flow path (101) is abnormal, the control circuit (104) cuts off the flow path (101) by means of a shut-off valve (102).)

1. A gas safety device is provided with:

a flow path for flowing the fuel gas;

a flow rate measuring unit that measures a flow rate of the gas flowing through the flow path;

a first pressure sensor that is disposed inside the flow path and measures an absolute pressure of the fuel gas;

a second pressure sensor disposed outside the flow path and configured to measure an absolute pressure of an atmospheric pressure;

a pressure value fluctuation detection unit that detects a fluctuation state of the absolute pressure measured by the first pressure sensor or the second pressure sensor;

a sensor drive control unit that controls driving of the first pressure sensor or the second pressure sensor in accordance with a value of fluctuation of the pressure value fluctuation detection unit;

a gas pressure determination unit that calculates a gas supply pressure based on a difference between a pressure value measured by the first pressure sensor and a pressure value measured by the second pressure sensor when the first pressure sensor and the second pressure sensor are both in a driving state;

a shut-off valve for shutting off the flow path; and

and a control circuit that controls the flow rate measurement unit and shuts off the flow path by the shut-off valve when it is determined that the flow rate measured by the flow rate measurement unit or the gas supply pressure calculated by the gas pressure determination unit is abnormal.

2. The gas safety device of claim 1,

the flow rate measuring unit includes a measuring circuit disposed inside the flow path, the first pressure sensor is configured on the measuring circuit,

the control circuit is disposed outside the flow path, and the second pressure sensor is disposed on the control circuit.

3. The gas safety device according to claim 1 or 2,

the flow rate measuring unit includes an ultrasonic flow rate measuring unit in which an ultrasonic sensor and a measuring circuit for driving the ultrasonic sensor to measure flow rate are integrated,

the ultrasonic flow rate measuring unit is provided in a gas atmosphere, the first pressure sensor is provided in the ultrasonic flow rate measuring unit, and the control circuit controls the ultrasonic flow rate measuring unit, thereby controlling the first pressure sensor in the ultrasonic sensor driving circuit.

4. A gas safety device is provided with:

a flow path for flowing the fuel gas;

a flow rate measuring unit for measuring a flow rate of the gas flowing through the flow path;

a first pressure sensor that is disposed inside the flow path and measures an absolute pressure of the fuel gas;

a second pressure sensor disposed outside the flow path and configured to measure an absolute pressure of an atmospheric pressure;

a first pressure value extraction unit that extracts n absolute pressures measured by the first pressure sensor;

a second pressure value extraction unit that extracts n absolute pressures measured by the second pressure sensor;

a first pressure previous value comparing section that compares a current measured value obtained by the first pressure value extracting section with a previous measured value;

a second pressure previous value comparing section that compares the current measurement value obtained by the second pressure value extracting section with the previous measurement value;

a drive stop determination unit that determines that the driving of the sensor is stopped based on the results of the first previous pressure value comparison unit and the second previous pressure value comparison unit;

a gas pressure determination unit that calculates a gas supply pressure based on a difference between the absolute pressure measured by the first pressure value extraction unit and the absolute pressure measured by the second pressure value extraction unit;

a shut-off valve for shutting off the flow path; and

and a control circuit that controls the flow rate measurement unit and shuts off the flow path by the shut-off valve when it is determined that there is an abnormality based on the flow rate measured by the flow rate measurement unit or the gas supply pressure measured by the gas pressure determination unit.

5. The gas safety device of claim 4,

the flow rate measuring unit includes a measuring circuit disposed inside the flow path, the first pressure sensor is configured on the measuring circuit,

the control circuit is disposed outside the flow path, and the second pressure sensor is disposed on the control circuit.

6. The gas safety device according to claim 4 or 5,

the flow rate measuring unit includes an ultrasonic flow rate measuring unit in which an ultrasonic sensor and a measuring circuit for driving the ultrasonic sensor to measure flow rate are integrated,

the ultrasonic flow rate measuring unit is provided in a gas atmosphere, the first pressure sensor is provided in the ultrasonic flow rate measuring unit, and the control circuit controls the ultrasonic flow rate measuring unit, thereby controlling the first pressure sensor in the ultrasonic sensor driving circuit.

Technical Field

The present disclosure relates to a gas safety device that measures a gas flow rate and cuts off a gas passage when an abnormal flow rate is measured, thereby ensuring safety in gas use.

Background

Conventionally, a gas safety device has been proposed in which a gas meter that measures the amount of gas used determines an abnormality and cuts off a gas passage to ensure safety (see patent document 1). The gas safety device includes an ultrasonic flow measuring unit in which an ultrasonic sensor is integrated with a circuit board constituting an ultrasonic sensor drive circuit, and a pressure sensor for measuring a pressure difference between a supply pressure side and an atmospheric pressure. The fuel cell system further has a control function of stopping the supply of the fuel gas by shutting off the flow path and a function of notifying the shut-off function when it is determined that the pressure difference between the supply pressure side measured by the pressure sensor and the atmospheric pressure is abnormal.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-98563

Disclosure of Invention

The pressure sensor incorporated in the gas safety device is a differential pressure measurement type pressure sensor that measures the pressure of gas with reference to atmospheric pressure, and therefore, has a through hole for introducing gas into the pressure sensor, and when the temperature around the gas safety device becomes extremely high, there is a possibility that gas leaks from the through hole. Therefore, as a structure that does not require a through hole, there is a method of: the change in the gas supply pressure is measured from the difference between the measured values of an absolute pressure sensor for measuring the atmospheric pressure and an absolute pressure sensor for measuring the pressure of the gas.

However, there are problems as follows: since 2 sensors are driven, power consumption increases, and it is necessary to increase the capacity of a battery in a gas safety device that is generally driven by a battery.

The gas safety device in the present disclosure includes: a flow path for flowing the fuel gas; a flow rate measurement unit for measuring a flow rate of the gas flowing through the flow path; a first pressure sensor that is disposed inside the flow path and measures the absolute pressure of the gas; a second pressure sensor which is disposed outside the flow path and measures an absolute pressure of the atmospheric pressure; and a pressure value fluctuation detection unit that detects a fluctuation state of the absolute pressure measured by the first pressure sensor or the second pressure sensor. Further, the apparatus comprises: a sensor drive control unit that controls driving of the first pressure sensor or the second pressure sensor based on a value of fluctuation of the pressure value fluctuation detection unit; and a gas pressure determination unit that calculates a gas supply pressure based on a difference between a pressure value measured by the first pressure sensor and a pressure value measured by the second pressure sensor when both the first pressure sensor and the second pressure sensor are in a driving state. Further, the apparatus comprises: a shut-off valve for shutting off the flow path; and a control circuit that controls the flow rate measurement unit and shuts off the flow path by the shut-off valve when it is determined that the flow rate measured by the flow rate measurement unit or the gas supply pressure calculated by the gas pressure determination unit is abnormal.

The present disclosure provides a gas safety device that does not eject gas even when the temperature around the gas safety device becomes high, and that can suppress power consumption even in a configuration including 2 absolute pressure sensors.

Drawings

Fig. 1 is a configuration diagram of a gas safety device according to a first embodiment.

Fig. 2 is an explanatory diagram of the operation of the gas safety device in the first embodiment.

Fig. 3 is a configuration diagram of a gas safety device in the second embodiment.

Fig. 4 is an explanatory diagram of the operation of the gas safety device in the second embodiment.

Detailed Description

The embodiments are described in detail below with reference to the drawings. However, unnecessary detailed description may be omitted.

(first embodiment)

The first embodiment will be described below with reference to fig. 1 to 2.

In fig. 1, a gas safety device 100 includes: a flow path 101 through which the fuel gas flows; a shut-off valve 102 for shutting off the flow path 101; a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101; and a control circuit 104 that integrates the usage amount of gas using the flow rate measurement data measured by the flow rate measurement unit 103. Further, the gas safety device 100 includes: a gas side absolute pressure sensor 105 as a first pressure sensor that measures the absolute pressure of the gas; an atmospheric-side absolute pressure sensor 106 as a second pressure sensor that measures the absolute pressure of the atmosphere; an electronic circuit 107 disposed in a gas environment; and a pressure value fluctuation detection unit 108 that detects the absolute pressure fluctuation state measured by the gas-side absolute pressure sensor 105. The gas safety device 100 further includes: a sensor drive control unit 109 for controlling the driving of the atmospheric-side absolute pressure sensor 106 based on the fluctuation state of the pressure value detected by the pressure value fluctuation detection unit 108; and a gas pressure determination unit 110 that calculates a gas supply pressure from a difference between 2 pressure values measured by the gas-side absolute pressure sensor 105 and the atmospheric-side absolute pressure sensor 106.

A gas-side absolute pressure sensor 105 as a first pressure sensor is mounted as an electronic component on an electronic circuit 107 provided in a gas atmosphere inside the flow path 101, and measures the absolute pressure of the gas in the flow path 101 based on a signal from the control circuit 104. Further, an atmospheric absolute pressure sensor 106 as a second pressure sensor is mounted as an electronic component on a control circuit 104 provided on the atmosphere side outside the flow path 101, and measures the absolute pressure of the atmosphere based on a signal from the control circuit 104.

Next, specific operations of the pressure value fluctuation detection unit 108 and the sensor drive control unit 109 will be described with reference to fig. 2.

Fig. 2 shows an example of a change in absolute pressure on the gas side and a change in absolute pressure on the atmosphere side in the same period, and a measurement timing of the gas-side absolute pressure sensor 105 as a first pressure sensor and a measurement timing of the atmosphere-side absolute pressure sensor 106 as a second pressure sensor.

As shown in the drawing, the gas-side absolute pressure sensor 105 is driven at predetermined intervals (for example, 2 seconds to 10 seconds) at all times to measure the absolute pressure. That is, the predetermined interval is an interval of the measurement timing of the gas-side absolute pressure sensor 105. When the gas-side pressure value fluctuation detection unit 108 detects that the absolute pressure measured by the gas-side absolute pressure sensor 105 has changed by a predetermined value (for example, 2kPa) or more, the sensor drive control unit 109 drives the atmosphere-side absolute pressure sensor 106 to measure the atmosphere-side pressure. When the change in the absolute pressure measured by the gas-side absolute pressure sensor 105 is smaller than a predetermined value, the measurement is stopped without driving the atmospheric-side absolute pressure sensor 106.

That is, the atmospheric absolute pressure sensor 106 is not driven until the measurement time Tn-1 of the gas side absolute pressure sensor 105 because the pressure change at predetermined intervals is less than 2 kPa. However, the pressure difference Δ Pgn between the absolute pressure Pgn-1 at the measurement time Tn-1 and the absolute pressure Pgn at the measurement time Tn is 2kPa or more, and the atmospheric absolute pressure sensor 106 is driven at the measurement time Tn to measure the atmospheric absolute pressure Pan. Then, at the next measurement time Tn +1, the pressure difference Δ Pgn +1 between the absolute pressure Pgn at the measurement time Tn measured by the gas-side absolute pressure sensor 105 and the absolute pressure Pgn +1 at the measurement time Tn +1 is less than 2kPa, and therefore, the driving of the atmospheric-side absolute pressure sensor 106 is stopped. Then, since the pressure change at each measurement time of the gas side absolute pressure sensor 105 is less than 2kPa, the driving of the atmosphere side absolute pressure sensor 106 is stopped.

Therefore, at the measurement time Tn, the gas side absolute pressure Pgn is measured by the gas side absolute pressure sensor 105 and the atmosphere side absolute pressure Pan is measured by the atmosphere side absolute pressure sensor 106, whereby the gas pressure determination unit 110 can calculate the gas supply pressure from the difference between the two measured pressure values. The control circuit 104 determines flow rate measurement data measured by the flow rate measurement unit 103, a gas supply pressure, or a change in the gas supply pressure, determines whether or not there is an abnormality such as gas leakage, and if it is determined that there is an abnormality, the shut-off valve 102 shuts off the flow path 101 to stop the supply of gas.

As described above, in the present embodiment, the absolute pressure on the gas side is normally measured only by the gas side absolute pressure sensor 105 as the first pressure sensor, and the driving and stopping of the atmosphere side absolute pressure sensor 106 as the second pressure sensor are controlled in accordance with whether or not a pressure change equal to or larger than a predetermined value is detected. With this configuration, power consumption can be suppressed, and the fluctuation of the gas supply pressure is detected by using the difference between 2 absolute pressure sensors capable of measuring the absolute pressure, so that a through hole required when using a pressure sensor of the differential pressure measurement type is not required, and a highly safe gas safety device can be realized.

In the present embodiment, the pressure value fluctuation detection unit 108 detects the pressure difference between the measurement timings of the gas-side absolute pressure sensor 105, but may detect the pressure fluctuation by the pressure difference between the separated measurement timings, the average pressure difference between a plurality of measurement timings, or a change pattern.

In the present embodiment, the description has been given of the configuration in which the stop and drive of the atmospheric side absolute pressure sensor 106 are controlled by measuring the pressure by the gas side absolute pressure sensor 105, but it goes without saying that the configuration in which the stop and drive of the gas side absolute pressure sensor 105 are controlled based on the pressure measurement by the atmospheric side absolute pressure sensor 106 may be equivalent.

It goes without saying that the ultrasonic flow measurement using the flow measurement unit 103 can be equivalently performed in the present embodiment.

In the present embodiment, the description has been made using the configuration in which the gas-side absolute pressure sensor 105 is mounted on the electronic circuit 107 provided in the gas atmosphere inside the flow path 101, but it goes without saying that it may be mounted in any place as long as it is inside the flow path. Further, although the description has been given using the structure in which the atmospheric absolute pressure sensor 106 is mounted on the control circuit 104 provided on the atmosphere side outside the flow path 101, the mounting location is not limited as long as the atmospheric pressure can be measured.

(second embodiment)

Next, a second embodiment will be described with reference to fig. 3 to 4. In fig. 3, the same components already described in fig. 1 are denoted by the same reference numerals, and the description thereof is omitted.

The gas safety device 200 includes: a flow path 101; a shut-off valve 102; a flow rate measurement unit 103 that measures the flow rate of the gas flowing through the flow path 101; and a control circuit 204 that integrates the usage amount of gas using the flow rate measurement data measured by the flow rate measurement unit 103. Further, the gas safety device 200 includes: a gas side absolute pressure sensor 105 as a first pressure sensor; an atmospheric-side absolute pressure sensor 106 as a second pressure sensor; an electronic circuit 107 disposed in a gas environment; and a sensor drive control unit 209 that controls driving of the gas-side absolute pressure sensor 105 and the atmospheric-side absolute pressure sensor 106. Further, the gas safety device 200 includes: a gas-side pressure value extraction unit 201 that extracts the pressure value measured by the gas-side absolute pressure sensor 105 n times; and an atmospheric pressure value extraction unit 202 that extracts the pressure value measured by the atmospheric absolute pressure sensor 106 n times. Further, the gas safety device 200 includes: a gas-side previous value comparing unit 220 that compares the previous pressure value obtained by the gas-side pressure value extracting unit 201 with the current pressure value; an atmospheric-side previous-value comparing unit 221 that compares the previous pressure value obtained by the atmospheric-side pressure value extracting unit 202 with the current pressure value; and a drive stop determination unit 205 that determines that the drive of the gas-side absolute pressure sensor 105 and the drive of the atmosphere-side absolute pressure sensor 106 are stopped, based on the results of the gas-side previous value comparison unit 220 and the atmosphere-side previous value comparison unit 221. The gas safety device 200 further includes a gas pressure determination unit 110, and the gas pressure determination unit 110 calculates the gas supply pressure based on the difference between the absolute pressure value extracted by the gas-side pressure value extraction unit 201 and the absolute pressure value extracted by the atmospheric-side pressure value extraction unit 202.

Next, a specific operation will be described with reference to fig. 4. The same components already described with reference to fig. 1 and 3 are denoted by the same reference numerals.

As shown in the drawing, the pressure measurement by the gas pressure determination unit 110 is periodically performed at predetermined time intervals T (for example, 2 seconds to 10 seconds). In fig. 4, the pressure measurement times T1 and T2 indicate the timing of pressure measurement. At the pressure measurement time T1, the gas-side pressure value extraction unit 201 extracts absolute pressure values from the first pressure value Pg (1) to the maximum nth pressure value Pg (n) measured at predetermined intervals (for example, 5ms) by the gas-side absolute pressure sensor 105. The atmospheric-side pressure value extraction unit 202 extracts absolute pressure values from the first pressure value Pa (1) to the maximum nth pressure value Pa (n) measured by the atmospheric-side absolute pressure sensor 106 at the same timing as the gas-side absolute pressure sensor 105.

When the 2 nd time pressure value is extracted by the gas side pressure value extraction unit 201, the gas side previous value comparison unit 220 compares the first pressure value Pg (1) with the 2 nd time pressure value Pg (2), and compares the pressure value with the previous value every time a measurement value is extracted thereafter. Similarly, when the pressure value Pa (2) of the 2 nd time is extracted by the atmospheric pressure value extraction unit 202, the atmospheric previous value comparison unit 221 compares the first pressure value Pa (1) with the pressure value Pa (2) of the 2 nd time, and compares the pressure value Pa (1) with the previous pressure value every time a pressure value is extracted thereafter.

The drive stop determination unit 205 stops driving of the gas-side absolute pressure sensor 105 and the atmosphere-side absolute pressure sensor 106 when it is determined that both the gas-side and atmosphere-side pressure values can be stably measured based on the comparison results of the gas-side previous value comparison unit 220 and the atmosphere-side previous value comparison unit 221.

That is, in the middle of the n measurements, when it is determined that the pressure value on the gas side Pg (k) measured at the k-th measurement and the pressure value on the gas side Pg (k +1) measured at the k + 1-th measurement are stable by comparison, and it is determined that the pressure value on the atmosphere side is stable by comparison of the pressure value on the atmosphere side Pa (k) measured at the k-th measurement on the atmosphere side and the pressure value on the atmosphere side Pa (k +1) measured at the k + 1-th measurement, the measurement of the k +2 th and subsequent times is stopped.

Whether or not the pressure value is being stably measured is determined by the difference between the pressure value acquired this time and the pressure value acquired last time being smaller than a predetermined value. The predetermined value may be the same value on the gas side and the atmospheric side, or may be set to a separate value.

The gas pressure determination unit 110 calculates the gas supply pressure based on the difference between the pressure value on the gas side measured the (k +1) th time in the gas side pressure value extraction unit 201 and the pressure value on the atmosphere side measured the (k +1) th time acquired by the atmosphere side pressure value extraction unit 202 when it is determined that the measured pressure value is stable. The control circuit 204 determines the flow rate measurement data measured by the flow rate measurement unit 103, the gas supply pressure, or the change in the gas supply pressure, determines whether or not there is an abnormality such as gas leakage, and if it is determined that there is an abnormality, the shut-off valve 102 shuts off the flow path 101 to stop the supply of gas.

Further, when the pressure measurement time T1 determines that the pressure value is unstable even if the pressure value is repeated n times based on the comparison result of the gas side previous value comparison unit 220 and the atmosphere side previous value comparison unit 221, the result is that the gas supply pressure is not calculated based on the difference of 2 absolute pressure values in the gas pressure determination unit 110 at the pressure measurement time T1. The same operation as described above is also performed at the pressure measurement time T2.

As described above, in the present embodiment, the 2 absolute pressure sensors (the gas side absolute pressure sensor 105 as the first pressure sensor and the atmospheric side absolute pressure sensor 106 as the second pressure sensor) are driven at the predetermined time interval T to perform measurement, but the driving and stopping of the 2 absolute pressure sensors may be controlled by determining the steady state of the pressure values measured by the 2 absolute pressure sensors, thereby suppressing power consumption.

That is, when the measured value is unstable due to external factors such as noise, the accurate pressure value can be measured by performing the measurement until the measured value is stable, and since noise or the like due to external factors is temporarily generated, the number of times of driving the absolute pressure sensor within 1 pressure measurement time can be reduced in normal measurement without noise or the like, and thus power consumption can be significantly reduced.

Further, a through hole required when using a differential pressure measurement type pressure sensor is not required, and a gas safety device with higher safety can be realized.

In the present embodiment, the method of comparing the 2 measurement results of the previous time and the current time by the gas side previous value comparing unit 220 and the atmosphere side previous value comparing unit 221 has been described, but it goes without saying that the sensor driving control may be performed by the driving/stopping determining unit 205 based on the comparison of the average value of the plurality of times up to the previous time and the current measurement value, and this is also possible.

In the present embodiment, the description has been made using the configuration in which the gas-side absolute pressure sensor 105 is mounted on the electronic circuit 107 provided in the gas atmosphere inside the flow path 101, but it goes without saying that the sensor may be mounted in any place inside the flow path 101. Further, although the description has been given using the structure in which the atmospheric absolute pressure sensor 106 is mounted on the control circuit 104 provided on the atmosphere side outside the flow path 101, the mounting location is not limited as long as the atmospheric pressure can be measured.

As described above, the first disclosure includes: a flow path for flowing the fuel gas; a flow rate measurement unit for measuring a flow rate of the gas flowing through the flow path; a first pressure sensor disposed inside the flow path and configured to measure an absolute pressure of the gas; and a second pressure sensor disposed outside the flow path and measuring an absolute pressure of the atmospheric pressure. Further, the apparatus comprises: a pressure value fluctuation detection unit that detects a fluctuation state of the absolute pressure measured by the first pressure sensor or the second pressure sensor; and a sensor drive control unit that controls the drive of the first pressure sensor or the second pressure sensor based on the value of the fluctuation of the pressure value fluctuation detection unit. Further, the apparatus comprises: a gas pressure determination unit that calculates a gas supply pressure based on a difference between a pressure value measured by the first pressure sensor and a pressure value measured by the second pressure sensor when the first pressure sensor and the second pressure sensor are both in a drive state; a shut-off valve for shutting off the flow path; and a control circuit that controls the flow rate measurement unit and shuts off the flow path by the shut-off valve when it is determined that the flow rate measured by the flow rate measurement unit or the gas supply pressure calculated by the gas pressure determination unit is abnormal.

With this configuration, it is possible to reduce power consumption while suppressing driving of the absolute pressure sensor on the atmosphere side. Further, since the through hole required when using the pressure sensor of the differential pressure measurement type is not required, the gas can be prevented from being ejected even when the temperature around the gas safety device becomes high, and a gas safety device with higher safety can be realized.

In particular, according to the first disclosure, the second disclosure may be configured such that the flow rate measurement section has a measurement circuit disposed inside the flow path, the first pressure sensor is configured on the measurement circuit, the control circuit is disposed outside the flow path, and the second pressure sensor is configured on the control circuit.

In particular, according to the first or second disclosure, the third disclosure may be configured such that the flow rate measurement unit includes an ultrasonic flow rate measurement unit in which an ultrasonic sensor and a measurement circuit for driving the ultrasonic sensor to perform flow rate measurement are integrated, the ultrasonic flow rate measurement unit is provided in a gas environment, the first pressure sensor is provided in the ultrasonic flow rate measurement unit, and the control circuit controls the ultrasonic flow rate measurement unit, thereby controlling the first pressure sensor also in the ultrasonic sensor drive circuit.

The fourth disclosure includes: a flow path for flowing the fuel gas; a flow rate measurement unit for measuring a flow rate of the gas flowing through the flow path; a first pressure sensor disposed inside the flow path and configured to measure an absolute pressure of the gas; and a second pressure sensor disposed outside the flow path and measuring an absolute pressure of the atmospheric pressure. Further, the apparatus comprises: a first pressure value extraction unit that extracts n absolute pressures measured by the first pressure sensor; and a second pressure value extraction section that extracts n absolute pressures measured by the second pressure sensor. Further, the apparatus comprises: a first pressure previous value comparing section that compares the current measurement value obtained by the first pressure value extracting section with the previous measurement value; a second pressure previous value comparing section that compares the present measurement value obtained by the second pressure value extracting section with the previous measurement value; and a drive stop determination unit that determines that the driving of the sensor is stopped based on the results of the first previous pressure value comparison unit and the second previous pressure value comparison unit. Further, the apparatus comprises: a gas pressure determination unit that calculates a gas supply pressure based on a difference between the absolute pressure measured by the first pressure value extraction unit and the absolute pressure measured by the second pressure value extraction unit; a shut-off valve for shutting off the flow path; and a control circuit that controls the flow rate measurement unit and shuts off the flow path by the shut-off valve when it is determined that the flow rate measured by the flow rate measurement unit or the gas supply pressure calculated by the gas pressure determination unit is abnormal.

With this configuration, it is possible to suppress the driving of the 2 absolute pressure sensors and reduce power consumption. Further, since the through hole required when using the pressure sensor of the differential pressure measurement type is not required, the gas can be prevented from being ejected even when the temperature around the gas safety device becomes high, and a gas safety device with higher safety can be realized.

In particular, according to the fourth disclosure, the fifth disclosure may be configured such that the flow rate measurement section has a measurement circuit disposed inside the flow path, the first pressure sensor is configured on the measurement circuit, the control circuit is configured outside the flow path, and the second pressure sensor is configured on the control circuit.

In particular, according to the fourth or fifth disclosure, the sixth disclosure may be configured such that the flow rate measurement unit includes an ultrasonic flow rate measurement unit in which an ultrasonic sensor and a measurement circuit for driving the ultrasonic sensor to perform flow rate measurement are integrated, the ultrasonic flow rate measurement unit is provided in a gas environment, the first pressure sensor is provided in the ultrasonic flow rate measurement unit, and the control circuit controls the ultrasonic flow rate measurement unit, thereby controlling the first pressure sensor also in the ultrasonic sensor drive circuit.

Industrial applicability

The safety of the gas safety device can be further improved, the cheaper gas safety device can be realized, and the gas safety device can be applied to common household gas meters, commercial gas meters and other purposes.

Description of the reference numerals

100. 200: a gas safety device; 101: a flow path; 102: a shut-off valve; 103: a flow rate measurement unit; 104. 204: a control circuit; 105: a gas-side absolute pressure sensor (first pressure sensor); 106: an atmospheric-side absolute pressure sensor (second pressure sensor); 107: an electronic circuit (measurement circuit); 108: a pressure value variation detecting section; 109. 209: a sensor drive control unit; 110: a gas pressure determination unit; 201: a gas-side pressure value extraction unit (first pressure value extraction unit); 202: an atmospheric pressure value extraction unit (second pressure value extraction unit); 205: a drive stop determination unit; 220: a gas-side previous value comparing section; 221: an atmosphere side previous value comparing section.