JP4612105B2 - Return safety confirmation method and electronic gas meter - Google Patents

Description

  The present invention relates to a return safety confirmation method for confirming safety when a gas supply is restored after the gas supply is shut off due to a gas supply abnormality or the like, and an electronic gas meter that implements the method.

  In recent years, electronic gas meters have a function of measuring the flow rate of gas flowing in a gas flow path, and the flow rate exceeds a predetermined total flow rate value (preset by summing the consumption flow rate of connected combustors). If the combustor is used continuously for a predetermined period or longer, an abnormality such as gas leakage in the gas flow path or forgetting to turn off the combustor is detected, and the gas shut-off valve is closed to The number of devices having a safety shut-off function that shuts off the gas supply through the flow path is increasing.

  In addition to the safety shut-off function at the time of abnormality, there is also a test shut-off function that shuts off the gas supply through the gas flow path by closing the gas shut-off valve for testing in order to check the operation status of the gas meter. .

  Therefore, when opening and returning a gas shut-off valve that has been closed by a safety shut-off function or a test shut-off function, the gas shut-off valve is opened only when it is safe, while checking safety for gas leaks. Need to be restored. Therefore, the gas meter is equipped with a function of checking the presence or absence of leakage for a predetermined time (recovery safety confirmation time) after being shut off by these shut-off functions, and setting it to a normal use state if there is no leak. This function is called a return safety confirmation function.

  A technique for providing a predetermined return safety confirmation time when returning after shut-off by the shut-off function is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-33289. In this technique, the return safety confirmation time at the time of return is fixed to a constant value (for example, 1 minute). If the gas flow rate does not change by a predetermined time before shut-off, the gas meter is put into a normal use state without waiting for the return safety check time when returning at shut-off, that is, without performing the return safety check work. It was.

JP 2001-33289 A

  In the above-mentioned technology, based on the presence or absence of the gas flow before shutoff, after the shutoff valve is automatically restored, the gas meter is immediately put into a normal use state without performing the return safety check work, or the return safety check work is performed. After that, the gas meter is in normal use.

  However, in the above-described technique, there is a case where the return safety confirmation work is not performed at the time of shutoff, and it cannot be said that the gas meter is safe for safe use. Therefore, it can be said that the return safety confirmation work must be performed at the time of interruption.

  However, when the shut-off function is used, the return safety check time is not necessarily set to a constant return safety check time. Although it may be good, in the conventional gas meter, as described above, the return safety confirmation time at the time of return is fixed to a constant value, so the end of the return safety check work will be waited until the time elapses. There is a problem that work efficiency deteriorates at the time of construction of the gas meter.

Therefore, in view of the above-described conventional problems, an object of the present invention is to provide a return safety confirmation method and an electronic gas meter capable of performing a return safety check earlier and safely.

  The return safety confirmation method according to the first aspect of the present invention provides a gas supply by opening the shut-off valve based on an input of a return signal after occurrence of a shut-off event in which the gas meter shut-off valve is closed and the gas supply is shut off. A return safety confirmation method for confirming return safety when returning the engine, monitoring the presence or absence of a flow rate immediately after the return, and if the flow rate is equal to or lower than a preset first flow rate threshold value, the first stable When setting the time and the flow rate exceeds the first flow rate threshold value, a second stabilization time longer than the first stabilization time is set, and after the first or second stabilization time has elapsed The return safety is confirmed based on the presence or absence of leakage flow rate.

  According to a second aspect of the present invention, in the return safety confirmation method according to the first aspect, if the leakage flow rate is present after the first or second stable time has elapsed, the shutoff valve is closed to supply gas. In addition to shutting off, when there is no leakage flow rate, the shutoff valve is kept open and the return safety check is completed.

  According to a third aspect of the present invention, there is provided an electronic gas meter comprising: a shut-off unit comprising a shut-off valve that shuts off a gas flow path; and a shut-off event in which gas supply is shut off by the shut-off valve, based on an input of a return signal. An electronic gas meter provided with a return safety check means for checking return safety when the valve is opened to return the gas supply, wherein the return safety check means monitors the flow rate immediately after the return, When the flow rate is less than or equal to a first flow rate threshold value set in advance, a first stabilization time is set, and when the flow rate exceeds the first flow rate threshold value, the first stabilization time is reached. A long second stabilization time is set, and return safety is confirmed based on the presence or absence of a leakage flow rate after the first or second stabilization time has elapsed.

  According to a fourth aspect of the present invention, in the electronic gas meter according to the third aspect, the return safety confirmation means controls the shutoff valve when the leakage flow rate is present after the first or second stable time has elapsed. The gas supply is shut off to shut off, and when there is no leakage flow rate, the shutoff valve is kept open and the return safety check is completed.

  According to a fifth aspect of the present invention, in the electronic gas meter according to the third or fourth aspect, the return safety confirmation means includes a flow rate monitoring unit that monitors an instantaneous flow rate of the gas flowing through the gas flow path, and the flow rate monitoring unit. A data calculation unit that calculates an instantaneous flow rate value by performing calculation based on the supplied detection output, a data storage unit that stores the instantaneous flow rate value calculated by the data calculation unit, A threshold value storage unit for storing a first flow rate threshold value set in advance and a second flow rate threshold value smaller than the first flow rate threshold value, and the instantaneous value stored in the data storage unit A data comparison unit that compares a flow rate value with the first and second flow rate threshold values stored in the threshold value storage unit and outputs a comparison result; and the data comparison unit immediately after return Instantaneous flow rate value and threshold Based on the comparison result of the first flow rate threshold value stored in the value storage unit, when the instantaneous flow rate value is less than or equal to the first flow rate threshold value, a first stabilization time is set and the flow rate is set. Is set to a second stabilization time longer than the first stabilization time when the first flow rate threshold value is exceeded, and the instantaneous time in the data comparison unit after the first or second stabilization time has elapsed If the instantaneous flow rate value is larger than the second flow rate threshold value based on the comparison result between the flow rate value and the second flow rate threshold value stored in the threshold value storage unit, the shut-off valve is A control unit for shutting off the gas supply by closing the valve, and maintaining the valve open of the shutoff valve and ending the return safety check when the instantaneous flow rate value is less than or equal to the second flow rate threshold value; It is characterized by including.

  According to the first and third aspects of the invention, the return safety confirmation work can be performed safely and quickly by setting the flow stabilization time after return to a different value depending on whether there is a large flow rate immediately after return. It is possible to improve work efficiency at the time of construction by the gas company.

  According to the second, fourth, and fifth aspects of the present invention, if there is a leakage flow rate during the return safety confirmation time, it is shut off again, and if there is no leakage flow rate, the return safety confirmation ends, so safety is improved.

It is a block diagram which shows the electronic gas meter which implements the return safety confirmation method which concerns on embodiment of this invention. It is a flowchart which shows the processing operation of the return safety confirmation function of the electronic gas meter of FIG.

  Embodiments of an electronic gas meter that implements the return safety confirmation method according to the present invention will be described below with reference to the drawings.

  The gas meter is equipped with a shutoff valve for shutting off the gas, but there are two situations when the shutoff event occurs. One is a case where the gas is cut off during gas use because it is judged that the situation is dangerous when an abnormality is detected during gas use, such as total flow cut off or usage time cut off. Is a case where gas is not used, such as a test shutdown. The difference between the two cases is that the pressure in the pipe on the downstream side of the meter is the atmospheric pressure in the former case, and that the gas supply pressure is maintained as it is in the latter case.

  Here, when a return operation is performed after shut-off, a return safety check is performed to detect leakage. However, in the case of an S-type gas meter, a determination time of 1 minute is always required regardless of the situation. Considering the actual gas flow, in the above-mentioned former case, after returning, it is necessary to supply gas into the pipe on the downstream side of the meter, so a large flow rate is instantaneously generated also in the gas meter section. . On the other hand, in the latter case, since there is no need to supply gas downstream of the gas meter, no instantaneous flow rate change occurs. The electronic gas meter periodically samples the instantaneous flow rate, and can capture the above-described flow rate change.

  Therefore, in the embodiment of the present invention, the situation at the time of interruption can be determined depending on whether or not the instantaneous flow of a large flow rate at the time of return is detected. The present invention proposes a return safety confirmation method that can be determined more quickly and accurately by switching automatically according to each situation and an electronic gas meter that implements the method.

  FIG. 1 is a block diagram showing an electronic gas meter that implements a return safety confirmation method according to an embodiment of the present invention. The electronic gas meter includes a flow rate monitoring unit 1, a data calculation unit 2, a data storage unit 3, a threshold storage unit 4, a data comparison unit 5, a return signal input unit 6, a control unit 8, and a cutoff unit 9.

  The flow rate monitoring unit 1, the data calculation unit 2, the data storage unit 3, the threshold value storage unit 4, the data comparison unit 5, and the control unit 8 function as return safety confirmation means in the claims.

The flow rate monitoring unit 1 monitors the flow rate of the gas flowing through the gas flow path, and includes a flow rate sensor such as an ultrasonic sensor or a flow sensor that can detect an instantaneous flow rate. Data calculation unit 2
Is supplied with a flow rate detection output from the flow rate monitoring unit 1 by sampling at a predetermined value interval, and calculates based on the supplied flow rate detection output to calculate an instantaneous flow rate.

  The data storage unit 3 stores the instantaneous flow rate calculated by the data calculation unit 2. The threshold value storage unit 4 stores a first flow rate threshold value set in advance and a second flow rate threshold value smaller than the first flow rate threshold value.

  The first flow rate threshold value is a threshold value for determining whether or not there is a large flow rate immediately after the return, and is set to, for example, 1000 liters / hour (L / h). The second flow rate threshold value is a threshold value for determining whether or not the leakage flow rate is flowing, and is set to, for example, 8.3 liters / hour (L / h).

  The data comparison unit 5 compares the instantaneous flow rate stored in the data storage unit 3 with the first or second threshold value stored in the threshold value storage unit 4, and outputs each comparison result. . The return signal input unit 6 includes a shut-off valve opening switch (not shown) that is turned on when a return button (not shown) is pressed.

  The control unit 8 outputs an instruction signal that instructs the flow rate monitoring unit 1 to perform flow rate sampling at predetermined value intervals. Further, the control unit 8 controls the shut-off valve 9 so as to close the shut-off valve or the shut-off valve controlled to open the shut-off valve in response to the input of the comparison result from the data comparison unit 5. Outputs a valve return signal. The shut-off unit 9 includes a shut-off valve that is controlled by a shut-off valve return signal or a shut-off valve close signal from the control unit 8 to open and close the gas flow path.

  The data calculation unit 2, the data storage unit 3, the threshold value storage unit 4, the data comparison unit 5 and the control unit 8 can be constituted by a microcomputer having a CPU, a ROM and a RAM. In this case, the CPU Serves as the data operation unit 2, the data comparison unit 5, and the control unit 8, the ROM serves as the threshold storage unit 4, and the RAM serves as the data storage unit 3.

  In the above-described configuration, when receiving the return signal from the return signal input unit 6, the control unit 8 outputs a shut-off valve return signal for return to the shut-off unit 9, and shifts to the return safety confirmation mode. At the same time, the control unit 8 instructs the instantaneous flow rate monitoring unit 1 to perform flow rate sampling. Each sampling result is calculated by the data calculation unit 2, and the calculated instantaneous flow rate value is stored in the data storage unit 3. The data comparison unit 5 checks whether a large flow rate is detected in the instantaneous flow rate immediately after the return. The data comparison unit 5 outputs a determination result on the presence or absence of a large flow rate to the control unit 8. In response to the determination result, the control unit 8 employs return safety logic prepared for each to check for leakage. When leakage is detected, the control unit 8 outputs a shut-off valve closing signal to the blocking unit 9, and when it is determined that there is no leakage, the return safety check is terminated and normal use is permitted.

  Next, the operation of the above-described electronic gas meter will be described with reference to the flowchart shown in FIG.

  FIG. 2 is a flowchart showing the processing operation of the return safety confirmation function.

  First, after a shut-off by any shut-off function, the shut-off valve opening switch is turned on by pressing the return button, whereby the return signal from the return signal input unit 6 is input to the control unit 8 (step S81).

  Next, the control unit 8 outputs a shut-off valve return signal based on the input of the return signal (step S82). Thereby, the cutoff part 9 is controlled by the cutoff valve return signal from the control part 8, and the cutoff valve is opened.

  Next, the control unit 8 instructs the flow rate monitoring unit 1 to sample the instantaneous flow rate (step S83). Thereby, a flow rate detection signal is output from the flow rate monitoring unit 1, calculated by the data calculation unit 2, and the calculated instantaneous flow rate value Qo is stored in the data storage unit 3.

  Next, the data comparison unit 5 determines whether or not the instantaneous flow rate Qo stored in the data storage unit 3 is larger than the first flow rate threshold value (step S84). If the answer is no, then the stabilization time parameter type 1 is set (step S85). By setting the stable time parameter type 1, it is set to a first predetermined value T1 (for example, 60 seconds) as a stable time parameter, and a stable time timer for counting the first predetermined value T1 is started.

  On the other hand, if the answer to step S63 is yes, then, the stable time parameter type 2 is set (step S86). By setting the stable time parameter type 2, the second predetermined value T2 as the stable time parameter (where T2> T1, for example, T2 = 150 seconds) is set, and the second predetermined value T2 is counted. The stabilization time timer starts.

  Next, the control unit 8 counts the first predetermined value T1 (for example, 60 seconds) set in step S85 or the second predetermined value (for example, 150 seconds) set in step S86. ) Is exceeded (step S87), and if the answer is Yes, the process proceeds to step S88.

  In step S88, the control unit 8 instructs the flow rate monitoring unit 1 to sample the instantaneous flow rate again. As a result, a flow rate detection signal is output from the flow rate monitoring unit 1, calculated by the data calculation unit 2, and the calculated instantaneous flow rate value Qn is stored in the data storage unit 3.

  Next, the data comparison unit 5 determines whether or not the instantaneous flow rate Qn stored in the data storage unit 3 is larger than the second flow rate threshold value (step S89). If the answer is No, then a return safety confirmation signal is outputted as a return safety check end (step S90), and then the process is ended.

  On the other hand, if the answer to step S89 is Yes, the control unit 8 then outputs a shut-off valve closing signal, controls the shut-off valve in the shut-off unit 9 to close, and closes the gas flow path (step S91). ), And then the process ends.

  In this way, it is confirmed whether or not a large flow rate is detected in the instantaneous flow rate measurement performed after the return signal is input. When a large flow rate is detected, it is probable that the gas was shut off during gas use, such as shutting off the total flow rate or shutting down the usage time, and the pressure in the pipe downstream of the meter was atmospheric pressure. When restoration is performed in such an environment, the timing at which leakage can be detected during the restoration safety check is not immediately after restoration, but after gas is supplied into the pipe and a certain amount of stabilization time has elapsed.

  If a large flow rate is detected immediately after the return, the presence or absence of leakage is determined based on the flow rate immediately after the return. The probability of misjudgment increases. In order to perform normal flow rate detection, it is necessary to perform leakage flow monitoring for confirmation of return safety after providing a stabilization time after return.

On the other hand, in cases where the gas is not used, such as in a test shutdown, the gas supply pressure is maintained as it is. . Therefore, when the large flow rate is not detected immediately after the return, the stabilization time can be shortened and the flow rate can be monitored for the return safety confirmation.

  As described above, according to the embodiment of the present invention, the return safety confirmation work is made faster and safer by setting the flow stabilization time after return to a different value according to the presence or absence of a large flow rate immediately after return. It can be carried out, and the work efficiency at the time of construction by the gas company can be improved. Further, if there is a leakage flow rate during the return safety confirmation time, it is shut off again, and if there is no leakage flow rate, the return safety check is completed, so the safety is improved.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to this, and various modifications and applications are possible.

  For example, each value such as the first flow rate threshold value, the second flow rate threshold value, and the stabilization time parameter type 1 & 2 in the above-described embodiment can be changed as appropriate.

1 Flow monitoring part (part of return safety confirmation means)
2 Data calculation part (part of return safety confirmation means)
3 Data storage (part of return safety confirmation means)
4 Threshold memory (part of return safety confirmation means)
5 Data comparison part (part of return safety confirmation means)
6 Return signal input section 8 Control section (part of return safety confirmation means)
9 Blocking part

Claims (5)

After the occurrence of a shut-off event in which the gas meter shut-off valve is closed to shut off the gas supply, the return safety check is performed to check the return safety when the shut-off valve is opened and the gas supply is restored based on the input of the return signal. A method,
The flow rate immediately after the return is monitored and if the flow rate is less than or equal to a first flow rate threshold value set in advance, a first stabilization time is set and the flow rate exceeds the first flow rate threshold value. A second stability time longer than the first stabilization time is set, and the return safety is confirmed based on the presence or absence of a leakage flow rate after the first or second stabilization time has elapsed. Confirmation method. In the return safety confirmation method according to claim 1,
If the leakage flow rate is present after the first or second stabilization time has elapsed, the shutoff valve is closed to shut off the gas supply, and if there is no leakage flow rate, the shutoff valve is opened. A return safety confirmation method characterized by maintaining the return safety confirmation and maintaining it. After the occurrence of a shut-off part comprising a shut-off valve for shutting off the gas flow path and a shut-off event in which the gas supply is shut off by the shut-off valve, when the shut-off valve is opened based on the input of a return signal, the gas supply is restored. An electronic gas meter equipped with return safety check means for checking return safety,
The return safety confirmation means monitors the flow rate immediately after the return, sets a first stable time when the flow rate is equal to or less than a first flow rate threshold value set in advance, and sets the flow rate to the first flow rate. If the flow rate threshold value is exceeded, a second stabilization time longer than the first stabilization time is set, and the return safety is confirmed based on the presence or absence of the leakage flow rate after the first or second stabilization time has elapsed. An electronic gas meter characterized by that. The electronic gas meter according to claim 3, wherein
The return safety confirmation means closes the shutoff valve to shut off the gas supply when the leakage flow rate is present after the first or second stabilization time has elapsed, and when the leakage flow rate is absent. An electronic gas meter, wherein the shutoff valve is kept open and the return safety check is completed. The electronic gas meter according to claim 3 or 4,
The return safety confirmation means includes
A flow rate monitoring unit for monitoring an instantaneous flow rate of the gas flowing through the gas flow path;
A detection output from the flow rate monitoring unit is supplied, and a data calculation unit that calculates based on the supplied detection output and calculates an instantaneous flow rate value;
A data storage unit for storing the instantaneous flow rate value calculated by the data calculation unit;
A threshold value storage unit for storing a first flow rate threshold value set in advance and a second flow rate threshold value smaller than the first flow rate threshold value;
A data comparison unit that compares the instantaneous flow rate value stored in the data storage unit with the first and second flow rate threshold values stored in the threshold value storage unit and outputs a comparison result When,
Based on the comparison result between the instantaneous flow rate value in the data comparison unit immediately after the return and the first flow rate threshold value stored in the threshold value storage unit, the instantaneous flow rate value is the first flow rate threshold value. A first stabilization time is set when the value is less than or equal to a value, and a second stabilization time longer than the first stabilization time is set when the flow rate exceeds the first flow rate threshold value, and the first stabilization time is set. Alternatively, the instantaneous flow rate value is calculated based on a comparison result between the instantaneous flow rate value in the data comparison unit after the second stable time has elapsed and the second flow rate threshold value stored in the threshold value storage unit. When the flow rate threshold value is greater than 2, the shutoff valve is closed to shut off the gas supply, and when the instantaneous flow rate value is less than or equal to the second flow rate threshold value, Keep the valve open and end the return safety check Electronic gas meter which comprises a control unit.

Images