JP2012242256A - Gas shut-off device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous shut-off by monitoring abnormal measurement in ultrasonic flow rate measurement.SOLUTION: A gas shut-off device comprises: flow rate detection means 3 for detecting flow signals; flow rate calculation means 10 for calculating instantaneous flow rate values from flow rate detection values; abnormal measurement determination means 13 in which abnormal measurement is determined when the flow rate signals cannot be detected by the flow rate detection means 3 or when an amplification degree in the flow rate detection means 3 is a predetermined value or more; period time counting means 14 for starting time counting after release of a forwarding mode and, after a predetermined period elapses, allowing the abnormal measurement determination means 13 to start operations; and shut-off means 17 in which an average flow rate is obtained from the instantaneous flow rates calculated by the flow rate calculation means 10, it is determined whether or not there is abnormality by abnormality determination means 16 on the basis of the obtained average flow rate, and supply of gas is shut off when it is determined that there is abnormality.

Description

  The present invention relates to a gas shut-off device, and more particularly to a gas shut-off device that performs flow rate measurement with ultrasonic waves and performs safety monitoring.

  Conventionally, as this type of gas shut-off device, there is one as shown in FIG. 3 (for example, see Patent Document 1).

  The configuration of the gas cutoff device of Patent Document 1 will be briefly described with reference to FIG.

  Two transducers TD1 and TD2 are arranged opposite to each other so as to be separated from each other by a distance L in the gas flow path and form an angle θ with respect to the gas flow direction Y. A gas shut-off valve 101 is provided on the upstream side of both transducers TD1, TD2. Each transducer TD1, TD2 is connected to a transmission circuit 104 and a reception circuit 105 via transducer I / F circuits 102, 103. Under the control of the microcomputer (μCOM) 106, the transmission circuit 104 drives one of the transducers TD1 and TD2 to generate an ultrasonic wave. The μCOM 106 includes a CPU 106a that performs various processes, a ROM 106b that stores programs, and a read-only memory RAM 106c. The reception circuit 105 processes the reception signals from the other transducers TD1 and TD2 that have received the ultrasonic signal that has passed through the gas flow path. A display 107 is connected to the μCOM 106.

  Next, the operation of the configuration of the conventional gas cutoff device will be described. The μCOM 106 measures the gas flow rate at each sampling time using the two transducers TD1 and TD2, and performs instantaneous flow rate measurement processing. In addition, the μCOM 106 performs a flow rate measurement process and a measurement abnormality determination process for determining whether accurate flow rate measurement can be performed. Then, when receiving the ultrasonic reception signal, the propagation time after the peak value exceeds the threshold value is measured. Here, the gain is adjusted so as to exceed the threshold, but the CPU 106a determines that accurate flow velocity measurement cannot be performed when the ultrasonic wave exceeding the threshold cannot be received even if the gain is maximized.

  After canceling the shipping mode, the CPU 106a performs a return process for confirming the return safety of the gas shut-off valve, and functions as a mixture determination unit and a stop unit. After the shipment mode is released, it is determined that a mixed state has occurred between the reception of the ultrasonic signal and the detection of the absence of mixing of supply gas and air based on the instantaneous flow rate calculated from the ultrasonic signal. Then stop judging the flow rate abnormality. After exiting this stop process, a return safety confirmation process is performed based on the determination of the flow rate abnormality.

  If no measurement abnormality has occurred, the CPU 106a determines whether or not the instantaneous flow rate has changed. If the difference between the previous and latest instantaneous flow rate is a certain value or more, it is judged that there is a fluctuation, and if it is less than a certain value, it is judged that there is no fluctuation. If a measurement abnormality has occurred or if the instantaneous flow rate is fluctuating although it can be measured, the CPU 106a is in gas replacement, and the air replacement flag is turned on because air and supply gas are mixed. Judging.

  If the gas replacement flag is not on, the flag is turned on and a replacement timer is started. When the replacement flag is on, it is determined whether or not the replacement timer has exceeded the first predetermined time. If it has exceeded, the CPU 106a functions as a shipping mode return means, and there is a measurement abnormality or flow rate fluctuation caused by gas mixture. Instead of occurring, it is determined that a measurement abnormality has occurred due to a failure of the transducers TD1, TD2, etc., and the process is shifted to the shipping mode and the process is terminated.

Japanese Patent No. 4199106

  However, in the gas shut-off device having the above-described conventional configuration, at the time of return safety confirmation after the release of the shipping mode, the mixture of air and supply gas is judged based on the reception state of ultrasonic waves and the instantaneous flow rate, and the judgment of the flow rate abnormality is stopped. However, it is not disclosed how to handle the abnormal flow value when stopping. In addition, the gas company may cancel the shipment mode after installation, but may purge the air with only some gas appliances, and other gases such as air remain in other piping There is. In this case, the gas flow path naturally mixes with a gas other than the supply gas as time elapses. Therefore, even in the air purge after the shipment mode is released, the gas replacement is completed, and it cannot be said that the mixed judgment is completed, and the flow measurement unit becomes mixed due to the convection of air in another gas pipe or water heater pipe. There is a case in which it is erroneously determined that the gas is mixed, and there is a problem that an erroneous interruption occurs.

  The present invention solves the above-described problems, and provides a highly convenient gas shut-off device that does not erroneously shut off even if a mixed state of a supply gas and a different gas such as air occurs in a gas flow path.

  In order to solve the above-described conventional problems, a gas shut-off device according to the present invention is a gas shut-off device that shuts off gas supply when an abnormality occurs, and includes a flow rate detection means that amplifies and detects a flow rate signal, and the flow rate detection A flow rate calculating means for calculating an instantaneous flow rate from a detected value of the means, and a measurement that determines a measurement abnormality when a flow rate signal cannot be detected by the flow rate detecting means, or when an amplification degree in the flow rate detecting means is a predetermined value or more. The abnormality determination means, the time measurement means that starts timing from the release of the shipping mode, and the measurement abnormality determination means starts to operate when a predetermined period of time elapses, and the gas supply is shut off when the measurement abnormality determination is established by the measurement abnormality determination means It consists of blocking means.

  According to the above invention, whether the flow rate detection means can correctly measure even in a shipping mode in which the gas shut-off device is still installed or in a state where gas can be supplied after the shipping mode is released to use the gas appliance? The measurement abnormality determination means for monitoring the initial function is in an invalid state, and the measurement abnormality determination means does not make a misjudgment even if there is a flow rate measurement with an abnormal amplification during that period after the shipment mode is released. The gas piping is not fully filled in the gas pipe immediately after opening in the new house by switching the measurement abnormality judgment means to function effectively after the gas appliance has been used sufficiently by the gas consumer and the predetermined period has elapsed. Even so, there is no problem of accidentally shutting off when returning from the result shipping mode, and safety monitoring can be performed safely.

  The gas shut-off device according to the present invention disables the function of the measurement abnormality determining means for a predetermined period after the gas consumer enters and starts using the gas appliance, and switches the function to active after the predetermined period has elapsed. Therefore, even if different gases such as air are mixed in the supply pipe at the beginning, the supply gas is sufficiently filled by setting a sufficient period for the replacement in the pipe with the supply gas to a predetermined period. In this state, the function of the measurement abnormality determining means can be made effective, and it is possible to prevent erroneous interruption.

Control block diagram of gas shutoff device in embodiment 1 of the present invention Control block diagram of gas cutoff device in embodiment 2 Control block diagram of a conventional gas shut-off device

  A first invention is a gas shut-off device that shuts off the supply of gas when an abnormality occurs, a flow rate detecting means for amplifying and detecting a flow rate signal, and a flow rate calculation for calculating an instantaneous flow rate from a detection value of the flow rate detecting means. And a measurement abnormality determination means for determining a measurement abnormality when the flow rate signal cannot be detected by the flow rate detection means, or when the amplification degree in the flow rate detection means is equal to or greater than a predetermined value, and the timing is started from the release of the shipping mode. Then, it comprises period measuring means for starting the operation of the measurement abnormality determining means when a predetermined period elapses, and interruption means for interrupting the supply of gas when the measurement abnormality determination means establishes a measurement abnormality.

  And measurement to monitor whether the flow rate detection means can be measured correctly even in the shipping mode with the gas shut-off device installed or in the state where the gas can be supplied after the release of the shipping mode to use the gas appliance The abnormality determining means is initially in a function invalid state, and even after a predetermined period has elapsed since the release of the shipping mode, the measurement abnormality determining means does not make a misjudgment even if there is a flow rate measurement with an abnormal amplification during that period. Even if the gas piping is not fully filled in the newly built house immediately after opening, it is possible to switch the measurement abnormality judgment means to function effectively after a predetermined period of time has passed since the gas appliance has been used sufficiently. As a result, it is possible to safely monitor the security without the problem of accidentally shutting off when returning from the shipping mode.

  In a second aspect of the invention, in particular, in the first aspect of the invention, after the measurement abnormality determination unit is operated by the period measurement unit, when the amplification degree in the flow rate detection unit is a predetermined value or more, the measurement of the predetermined period is performed again. Retry determination means for starting operation is provided.

  And even after providing a sufficient period, when mixing of different gas is recognized, it is possible to prevent erroneous blockage by the measurement abnormality determining means by measuring the predetermined period again.

  The third invention is a program for causing a computer to execute all or part of the means of the shut-off device of the first or second invention.

  And since it is a program, a part or all of the gas interruption | blocking apparatus of this invention can be easily implement | achieved using a microcomputer etc. Also, program distribution and installation can be simplified by recording on a recording medium or distributing a program using a communication line.

(Embodiment 1)
FIG. 1 is a control block diagram of the gas shutoff device according to Embodiment 1 of the present invention. The same number is attached | subjected to the equivalent to FIG.

  Although not shown, the gas shut-off device is installed in the garden of each household, and after passing through this gas shut-off device, it is piped to the place where various gas appliances used in each home are installed, and gas is supplied. The The internal configuration of the gas cutoff device includes a flow path and a control device. The flow path is connected to a supply port for supplying gas to each gas appliance through the inlet side flow path from the inlet of the gas shut-off device, through the flow path at the bottom, and through the outlet side flow path. An upstream transmitter / receiver 1 and a downstream transmitter / receiver 2 that transmit and receive ultrasonic signals are attached to the upstream and downstream sides of the flow path so as to face each other.

FIG. 1 is a control block diagram of the gas cutoff device. The flow rate detection means 3 includes an upstream transceiver 1, a downstream transceiver 2, a switching means 4, a transmission means 5, a reception means 6, a propagation time measurement means 7, an amplitude determination means 8, and an amplification degree adjustment means 9. The switching means 4 can switch the transmission / reception of the upstream transmitter / receiver 1 for transmitting or receiving ultrasonic waves and the downstream transmitter / receiver 2 for receiving or transmitting ultrasonic waves. Transmitting means 5 for outputting an ultrasonic signal is connected to the upstream transceiver 1 or the downstream transceiver 2, and the ultrasonic signal is received by the switching means 4 via the upstream transceiver 1 or the downstream transceiver 2. 6 is received.

  In this configuration, first, an ultrasonic signal is transmitted from the upstream transceiver 1 by the transmission means 5 and received by the downstream transceiver 2, and the propagation time is measured by the propagation time measurement means 7 from the reception signal from the reception means 6. . Next, switching is performed by the switching means 4, and similarly, an ultrasonic signal is transmitted from downstream to upstream, and the propagation time is measured. Then, the ultrasonic propagation time difference between the upstream side transceiver 1 and the downstream side transceiver 2 is obtained every predetermined period (for example, every 2 seconds). The ultrasonic signal received by the receiving unit 6 is determined by the amplitude determining unit 8 to determine whether the amplitude is an appropriate magnitude. If the ultrasonic signal is too large or too small, the amplification level adjusting unit 9 adjusts the ultrasonic signal to an appropriate magnitude. adjust. Next time, an ultrasonic signal is transmitted from the transmission means 5 with the adjusted amplification degree.

  The propagation time measured and determined for each predetermined period is converted into an instantaneous flow rate value by the flow rate calculation means 10. The instantaneous flow rate value is input to the average flow rate calculation means 11, and a predetermined number of instantaneous flow rate values are collected and calculated as an average flow rate. On the other hand, the amplification degree determination means 12 monitors the amplification degree for adjusting the amplitude level of the ultrasonic signal of the flow rate detection means 3. Usually, when the flow rate is increased, the ultrasonic signal reception sensitivity is lowered, and therefore the amplification degree tends to be increased.

  The measurement abnormality determination unit 13 determines whether there is an abnormality in the flow rate detection unit 3. For example, when the amplification level of the amplification level determination unit 12 is equal to or greater than a predetermined value, it is determined that the ultrasonic reception signal is abnormally lowered for some reason. Further, when the flow rate detecting means 3 transmits an ultrasonic signal from the upstream side transceiver 1 and cannot be received by the downstream side transceiver 2, or the downstream side transceiver 2 receives the ultrasonic signal and transmits the propagation time measuring means 7. When a propagation time other than the original supply gas is detected, it is determined that a foreign gas such as air or helium gas is mixed, and it is determined that the flow rate cannot be correctly measured using ultrasonic waves.

  The period measuring means 14 starts measuring the period for a predetermined period after the shipment mode is canceled. The gas shut-off device is set to a shipping mode at the time of shipment, and in this shipping mode, the measurement abnormality determination means 13 is ineffective and does not operate the abnormality determination. Then, after the gas shut-off device is installed by the gas company, it is released from this shipping mode state, and when the normal gas appliance is used, the time counting means 14 starts timing. Thereafter, when the time keeping for a predetermined period is completed, the measurement abnormality determining means 13 is switched to function-effective, and performs abnormality determination relating to various measurements.

  The shipping mode release means 15 is, for example, a reed switch called a test switch, which is operated by a magnet or the like so that the gas company releases the shipping mode state, and an operation signal is input. When operated, when a shipping mode state is reached, or when a return switch (not shown) for releasing and returning is operated, a normal state is reached in which the gas appliance can be used after a predetermined time.

  The amplification degree determination means 12 has a large instantaneous flow rate obtained by the flow rate calculation means 10 while the gas abnormality is not being used while the measurement abnormality determination means 13 is ineffective, and the amplification degree determined by the amplification degree determination means. When the degree shows a value greater than or equal to the predetermined value, it is determined that the mixed state of the supply gas and other gases has been sufficiently generated in the piping even after the shipment mode is canceled, and the instantaneous flow rate measured at that time is not used. The instantaneous flow rate measured at the normal amplification degree is adopted and output to the average flow rate calculation means 11.

The amplification degree determination means 12 has a plurality of determination values. For example, dust or the like accumulates in the upstream transmitter / receiver 1 or the downstream transmitter / receiver 2 so that the flow rate cannot be measured unless the gain is gradually increased. The device 1 and the downstream transmitter / receiver 2 are disconnected, resulting in a high amplification degree and a plurality of determination values such as a determination value for determining that the flow rate cannot be measured. For example, if the gas pipe is in a mixed state with a different gas such as air, the dust detection level may be exceeded, or the judgment value that cannot be measured may be exceeded. May show high flow rate.

  Then, the abnormality determination unit 16 monitors the appliances used at the obtained average flow rate or monitors whether there is an abnormality in the current flow rate detection unit 3. The abnormality determination unit 16 stores a time limit value for use time corresponding to each flow rate region, a monitor determination value for the maximum use flow rate, or the like. For example, when a hose that supplies gas to a gas stove or the like is disconnected for some reason, an abnormally large flow rate occurs, but the total flow cutoff value for monitoring such a condition or the maximum normal use of gas appliances Stored is a time limit for shutting down a use time that defines a time limit for use time corresponding to a case where the use time is much longer than the use time. By comparing and determining the set value and the average flow rate by the abnormality determination means 16, the flow rate value does not exceed the maximum use flow rate value, or the use time of the gas appliance is set to the time limit for continuous use corresponding to the registered flow rate. Monitor whether it has exceeded.

  When the abnormality determination means 16 determines that an abnormality has been established, it sends a cutoff signal to the cutoff means 17 to stop the gas supply. Further, the notification communication means 18 displays the shut-off state and shut-off content on a liquid crystal display element or the like (not shown), and a telephone line or the like at the center (not shown) of a gas company that monitors gas safety. Report by means of communication.

  Next, the operation of the gas shut-off device configured as described above will be described. When the gas shut-off device is newly built or replaced by inspection, it is in a shipping mode by operating a switch called a test switch. Then, before the gas customer enters and starts using the gas appliance, the shipping mode is canceled by the gas company, and the blocking means 17 is restored. Then, using a gas appliance, a different gas different from the supply gas such as gas leakage or air in the pipe is purged.

  However, the shipping mode may be canceled from the non-occupancy stage so that gas can be used immediately. In such a case, the gas purging may be finished using only the gas table of the gas table, and the gas piping may not be sufficiently filled with the supply gas. Under such circumstances, when the flow rate measurement is performed, the flow path becomes a mixed state of supply gas, air, etc. as time passes, and the ultrasonic waves transmitted from the upstream side transceiver 1, the downstream side transceiver 2, etc. Propagation occurs in the gas mixture, and refraction occurs and the received signal level becomes small.

  When the flow rate is detected by the amplitude determination unit 8 of the flow rate detection unit 3 in such a state, the signal is amplified by the amplification level adjustment unit 9, but the amplification level becomes abnormally high because the mixed state continues. In this state, the propagation time of the ultrasonic signal is measured as a detected value, and this signal is sent to the flow rate calculation means 10 and converted into an instantaneous flow rate value. Since the level of the received signal between the transmitter / receiver 2 fluctuates and the signal propagation time constantly fluctuates, the propagation time value measured by the propagation time measuring means 7 is the flow rate state where no gas appliance is used. As a result, the flow rate value obtained by the flow rate calculation means 10 varies.

  Although the gas shut-off device is initially installed in the shipping mode state, the shipping mode may be canceled and restored depending on the installation form. The period measuring means 14 starts counting the timer after the normal supply gas can be used from the shipping mode released state, and the function of the measurement abnormality determining means 13 is in an invalid state during this count. The predetermined period measured by the period measuring unit 14 can be changed by communication or the like, but is set to several weeks, for example.

  Then, when a signal in a mixed state with a gas other than the supply gas is output by the output signal of the amplification degree determination means 12 while the period counting means 14 is operating, the instantaneous flow rate of the flow rate calculation means 10 at that time is not used. For example, the instantaneous flow rate measured with the amplification degree in the normal state before the output signal of the amplification degree determination unit 12 is determined to be abnormal is used and output to the average flow rate calculation unit 11.

  Further, when the period measuring unit 14 measures a predetermined period, the measurement abnormality determining unit 13 is switched to function effective. That is, when the gas consumer uses the gas appliance during this predetermined period, the supply pipe is sufficiently purged with the supply gas, switched, and does not enter a mixed state with other gases. Measurement does not occur.

  After that, when the amplification degree determination means 12 is equal to or higher than a predetermined level, there is a high possibility that the upstream transmitter / receiver 1 or the downstream transmitter / receiver 2 has deteriorated over time or has become a channel state in which normal measurement is difficult due to dust or the like. . Therefore, such a state is detected by the measurement abnormality determining means 13 and output to the abnormality determining means 16 to drive the shut-off means 17 to stop the gas supply.

  When the abnormality determination means 16 determines that an abnormality has been established, it sends a cutoff signal to the cutoff means 17 to stop the gas supply. Further, the notification communication means 18 displays the shut-off state and the shut-off content on a liquid crystal display element or the like and notifies the center of the gas company that is monitoring the safety of the gas by communication such as a telephone line. The gas company can immediately take countermeasures such as replacing the gas shut-off device, and can quickly avoid abnormal conditions.

  In parallel, the average flow rate calculation means 11 calculates the instantaneous flow rate obtained by the flow rate calculation means 10 as an average flow rate for each predetermined number. The abnormality determination unit 16 stores a time limit value for use time corresponding to each flow rate region, a monitor determination value for the maximum use flow rate, or the like. For example, when a hose that supplies gas to a gas stove or the like is disconnected for some reason, an abnormally large flow rate occurs, but the total flow cutoff value for monitoring such a state or the maximum normal use of the gas appliance Stored is a time limit for shutting down a use time that defines a time limit for use time corresponding to a case where the use time is much longer than the use time.

  Then, by comparing and determining the set value and the average flow rate by the abnormality determination unit 16, the flow rate value does not exceed the maximum use flow rate value, or the usage time of the gas appliance is limited to the continuous use corresponding to the registered flow rate. It monitors whether the time is exceeded or not, and outputs a cut-off signal when it exceeds.

  Note that the configuration used in the present embodiment is an example, and the usage pattern is not limited to the present embodiment.

  As described above, the measurement abnormality determination means 13 of the gas shut-off device is initially in an invalid function state regardless of the presence or absence of gas mixing in the supply pipe. By monitoring whether or not the function of the flow rate detection unit is functioning normally, the flow rate detection unit 3 erroneously measures the flow rate under the mixed gas, and it is erroneous that the flow rate detection unit 3 is abnormal. Since the gas shut-off device can be operated normally, the safety and reliability are extremely high. is there.

(Embodiment 2)
FIG. 2 is a control block diagram of the gas cutoff device according to Embodiment 2 of the present invention. The same number is attached | subjected to the equivalent to FIG.1 and FIG.3.

  FIG. 2 is a control block diagram of the shutoff device, which is different from the first embodiment in that a retry determination means 19 is provided. The retry determination unit 19 is input when the amplification level determination unit 12 that monitors the signal level of the ultrasonic signal of the flow rate detection unit 3 has reached an amplification level equal to or greater than a predetermined value after the period measurement unit 14 is activated. Then, the timing of the period measuring means 14 is restarted from zero. That is, after the shipment mode is released, it is determined that the air purge in the supply gas piping is not sufficient and is in a mixed state with a different gas other than the supply gas, and the function validity switching of the measurement abnormality determination means 13 is further delayed.

  Next, the operation of the gas shut-off device configured as described above will be described. The gas shut-off device is in a shipping mode that is set by a gas operator through a magnet switch, for example, a reed switch called a test switch, when the gas shut-off device is newly constructed or replaced by inspection. Before the gas customer enters and starts using the gas appliance, the shipping mode is canceled by the gas company, and the blocking means 17 is restored. Then, using a gas appliance, a different gas different from the supply gas such as gas leakage or air in the pipe is purged. However, there are various installation forms. For example, the shipping mode may be canceled from the non-occupied stage so that gas can be used immediately.

  In such a case, there may be a case where the gas purge is simply performed by using only the gas table or the gas purge is completed, and the gas pipe may be sufficiently replaced with the supply gas to be not filled. When the flow measurement is performed under such circumstances, the supply gas, air, and the like are mixed with the convection and the like as time passes, and the upstream transmitter / receiver 1, the downstream transmitter / receiver 2, etc. The transmitted ultrasonic wave propagates in the mixed gas.

  Therefore, the transmitted ultrasonic waves reach the receiving side transceiver while undergoing refraction when passing between gases having different densities. At this time, the received ultrasonic signal level is generally small. When such a state is detected by the amplitude determining means 8 of the flow rate detecting means 3, the signal is amplified by the amplification adjusting means 9. However, since the signal level is small, the amplification in the mixed state is compared with the case of the original supply gas. It becomes abnormally high and this state continues for a long time.

  If the propagation time of the ultrasonic signal is measured in such a state, the propagation time between different gases can be measured, or the measurement can be performed with a low signal level in a mixed state. Is sent to the flow rate calculation means 10 and converted into an instantaneous flow rate value. As a result, since the measurement is performed in a mixed state with a high degree of amplification, the level of the received signal between the upstream side transceiver 1 and the downstream side transceiver 2 fluctuates and the signal propagation time constantly varies. Since the propagation time value measured by the propagation time measuring means 7 changes even though the flow rate is not used at all, the flow value obtained by the flow rate computing means 10 fluctuates even though the gas appliance is not originally used. .

  Since there is a state at the time of installation described above, the gas shut-off device is first installed in the shipping mode state, and the measurement abnormality determination means 13 is disabled. However, at the time of installation, the shipping mode may be canceled and returned to the state, and the function of the measurement abnormality determination unit 13 is continuously disabled. The period measuring means 14 starts a timer count for a predetermined period after normal supply gas can be used from the shipping mode release state. Although this predetermined period can be changed by communication or the like, it is set, for example, for a period of several weeks in consideration of the period of use of the gas appliance from the occupancy of the gas consumer. First, the period timer is counted.

  When an output signal determined to be equal to or higher than the predetermined amplification level is input from the amplification level determination unit 12 while the period measuring unit 14 is counting, a signal indicating that the gas is mixed with a gas other than the supply gas is output, and the retry is performed. Input to the determination means 19. When the retry determination unit 19 receives a signal indicating that it is in the mixed state, the retry determination unit 19 instructs the time counting unit 14 to recount the time. As a result, the period measuring means 14 resets the clock timer and starts counting again. At the same time, the instantaneous flow rate of the flow rate calculation means 10 is not used, and the average flow rate calculation means 11 is used by using the instantaneous flow rate measured with the normal state amplification level before the output signal of the amplification degree determination means 12 is determined to be abnormal. Output to.

Then, when the predetermined period is measured by the period measuring unit 14, the function of the measurement abnormality determining unit 13 is switched to be valid. That is, when the gas customer uses the gas appliance during this predetermined period, the inside of the supply pipe is sufficiently purged with the supply gas, switched to the supply gas, and not mixed with other gases. The flow rate measurement value in the state is not adopted. If the amplification degree determination means 12 becomes equal to or higher than a predetermined level after the predetermined period, there is a possibility that the upstream transmitter / receiver 1 or the downstream transmitter / receiver 2 has deteriorated over time or has become a flow path state in which normal measurement is difficult due to dust or the like Is expensive. Therefore, such a state is detected by the measurement abnormality determining means 13 and output to the abnormality determining means 16 to drive the shut-off means 17 to stop the gas supply.

  When the abnormality determination means 16 determines that an abnormality has been established, it sends a cutoff signal to the cutoff means 17 to stop the gas supply. Further, the notification communication means 18 displays the shut-off state and the shut-off content on a liquid crystal display element or the like and notifies the center of the gas company that is monitoring the safety of the gas by communication such as a telephone line. The gas company can immediately take countermeasures such as replacing the gas shut-off device, and can quickly avoid abnormal conditions.

  In parallel, when the amplification degree determination means 12 determines that the amplification degree is equal to or greater than a predetermined value, that is, when it is determined that the mixture state is different gas, the measured instantaneous flow rate at the normal amplification degree is used. Therefore, the average flow rate calculation means 11 calculates the average flow rate for each predetermined number in addition to the instantaneous flow rate obtained by the flow rate calculation means 10. Since the obtained average flow rate does not use the measured flow rate in the mixed state, the abnormal determination unit 16 does not jump through the abnormal flow rate. Then, the abnormality determining means stores the time limit value for use time corresponding to each flow rate region, the monitoring determination value for the maximum use flow rate, or the like based on the obtained average flow rate.

  For example, when a hose that supplies gas to a gas stove or the like is disconnected for some reason, an abnormally large flow rate occurs, but the total flow cutoff value for monitoring such a state or the maximum normal use of the gas appliance Stored is a time limit for shutting down a use time that defines a time limit for use time corresponding to a case where the use time is much longer than the use time. By comparing and determining the set value and the average flow rate by the abnormality determination means 16, the flow rate value does not exceed the maximum use flow rate value, or the use time of the gas appliance is set to the time limit for continuous use corresponding to the registered flow rate. Monitors whether it exceeds the limit, and outputs a cut-off signal if exceeded.

  Note that the configuration used in the present embodiment is an example, and the usage pattern is not limited to the present embodiment.

  As described above, the measurement abnormality determination means 13 of the gas shut-off device is in a function invalid state after installation because the gas in the supply pipe is mixed with the different gas, and during the time measurement by the time measurement means 14 for a predetermined period. When the mixed state with the different gas is detected, the period timer is reset to zero again and counted again, and the measurement abnormality determination means 13 becomes effective only after a predetermined period of time elapses, and the function of the flow rate detection unit operates normally. Monitor whether or not

  In this way, the flow rate detection means 3 can be prevented from erroneously determining that the flow rate detection means 3 is erroneously measuring the flow rate with a mixed gas as if the flow rate detection means 3 is abnormal and blocking it, and monitoring using a gas appliance. Since the gas shut-off device is normally operated, safety and reliability are extremely high, and there is an effect that the gas operator has high usability without causing unnecessary operation.

  As described above, the gas shutoff device according to the present invention is for preventing measurement abnormality due to different gas in the supply pipe at the time of installation, and can be applied to all flow measuring devices such as water meters. is there.

DESCRIPTION OF SYMBOLS 3 Flow rate detection means 10 Flow rate calculation means 11 Average flow rate calculation means 12 Amplification degree determination means 13 Measurement abnormality determination means 14 Period measurement means 16 Abnormality determination means 17 Blocking means 19 Retry determination means

Claims (3)

A gas shut-off device that shuts off the gas supply when an abnormality occurs,
A flow rate detection means for amplifying and detecting the flow rate signal;
A flow rate calculation means for calculating an instantaneous flow rate from a detection value of the flow rate detection means;
When the flow rate signal cannot be detected by the flow rate detection unit, or when the amplification degree in the flow rate detection unit is a predetermined value or more, a measurement abnormality determination unit that determines a measurement abnormality,
Time counting means for starting time measurement from the release of the shipping mode and starting operation of the measurement abnormality determining means when a predetermined period has elapsed;
A shut-off means for shutting off the supply of gas when the measurement abnormality judgment means establishes a measurement abnormality; and
Gas shut-off device with 2. A retry determination unit for starting operation of a predetermined period of time again when the amplification degree in the flow rate detection unit is a predetermined value or more after the measurement abnormality determination unit is operated by the period measurement unit. Gas shut-off device. A program for causing a computer to function as all or part of means of the shut-off device according to claim 1.

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