JP4208439B2 - Gas meter and earthquake judgment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas meter, and more particularly to a technology for detecting vibration caused by an earthquake to cut off gas supply or determine an earthquake.
[0002]
[Prior art]
Conventionally, gas meters equipped with a seismic device are known. In this gas meter, the seismic device detects vibration and outputs it as a pulse signal, and the control unit determines that an earthquake has occurred based on this pulse signal and cuts off the gas supply. However, this gas meter has a drawback that it is erroneously determined that an earthquake has occurred even when vibrations other than those based on the earthquake are detected.
[0003]
Therefore, in order to eliminate this drawback, an improved gas meter has been developed in which the waveform of the pulse signal output from the seismoscope is observed and only the earthquake is detected based on the observation result. For example, it is possible to detect the intensity of shaking using a gas meter that detects only earthquakes by using a detection circuit that detects the characteristics of the seismic wave that there are multiple long pulses in a certain time, and a seismometer that has different shaking detection sensitivities. Gas meters that detect only earthquakes have been developed.
[0004]
[Problems to be solved by the invention]
However, the gas meter may sway and resonate with the piping that fixes the gas meter when a strong impact is applied. In this case, a large and long vibration is generated in the gas meter, and the pulse signal output from the seismic sensor has a waveform similar to that of an earthquake pulse signal. As a result, there is a problem that it is erroneously determined that an earthquake has occurred despite the impact.
[0005]
An object of the present invention is to solve such a problem. By distinguishing between an earthquake and an impact, a gas meter capable of reliably shutting off gas supply only at the time of the earthquake and an earthquake and an impact are provided. It is to provide a seismic determination method that can be distinguished.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, a gas meter of the present invention detects a vibration with different sensitivities and outputs a plurality of pulse signals corresponding to the different sensitivities, and each pulse signal from the seismic detectors. A detection circuit for detecting whether or not a predetermined number of pulses having a predetermined width or more are included within a first predetermined time, a time measurement circuit for measuring a time difference at the start of pulse output of each pulse signal from the seismic sensor, and If the detection circuit detects that a predetermined number of pulses having a predetermined width or more are included in the first predetermined time, whether the vibration is an earthquake vibration or an impact vibration based on the time difference measured by the time measurement circuit. A controller for determiningA wavelength measuring circuit for measuring a wavelength of a pulse signal from the seismic device, wherein the controller detects that the detection circuit includes a predetermined number of pulses having a predetermined width or more within a first predetermined time, and When the time difference measured by the time measurement circuit is less than a second predetermined time and the wavelength measured by the wavelength measurement circuit is greater than or equal to a predetermined length, it is determined that the vibration is vibration caused by an earthquake. Shut off the supply ofIt is characterized by that.
[0007]
  According to this gas meter, as in the prior art, only whether each pulse signal from the seismic device, which is one of the features of an earthquake, contains a predetermined number or more of pulses having a predetermined width or more within the first predetermined time, It cannot be distinguished whether the vibration is based on an earthquake or an impact. However, in the gas meter of the present invention, it is further determined whether the vibration is a vibration caused by an earthquake or a vibration caused by an impact, based on a time difference at the start of pulse output of the pulse signal from the seismic device. Also,The controller detects that the detection circuit includes a predetermined number of pulses having a predetermined width or more within the first predetermined time, and the time difference measured by the time measurement circuit is less than the second predetermined time, and the wavelength measurement circuit When the measured wavelength is equal to or longer than the predetermined length, it is possible to determine that the vibration is a vibration caused by an earthquake and shut off the gas supply.
[0008]
  The earthquake determination method of the present invention includes a first step of detecting vibrations with different sensitivities and outputting a plurality of pulse signals corresponding to the different sensitivities, and each pulse signal having a predetermined width or more within a first predetermined time. A second step for detecting whether or not a predetermined number of pulses are included, a third step for measuring a time difference at the start of pulse output of each pulse signal, and a pulse having a predetermined width or more within the first predetermined time. A fourth step of determining whether the vibration is a vibration caused by an earthquake or a vibration caused by an impact based on the time difference measured in the third step,A fifth step of measuring the wavelength of the pulse signal output in the first step, wherein the fourth step includes a predetermined number of pulses having a predetermined width or more within the first predetermined time in the second step. Is detected and the time difference measured in the third step is less than a second predetermined time and the wavelength measured in the fifth step is greater than or equal to a predetermined length, the vibration is a vibration due to an earthquake. It is determined that the gas supply is cut off.
[0009]
According to this earthquake determination method, the same operation and effect as the operation and effect of the gas meter can be obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The gas meter and the earthquake determination method capable of distinguishing between an earthquake and an impact according to an embodiment of the present invention will be described below in detail with reference to the drawings.
[0011]
(First embodiment)
FIG. 1 is a block diagram showing the configuration of the gas meter according to the first embodiment of the present invention. This gas meter includes a multistage seismic device 1 as a seismic device, a detection circuit 2, a time measurement circuit 3, a shut-off valve 4, a communication interface (communication I / F) 5, a display unit 6, and a controller 7.
[0012]
As shown conceptually in FIG. 2, the multistage seismic device 1 has a configuration in which a first seismic device 10 and a second seismic device 11 are integrally formed. The first seismic device 10 can be considered as a switch having one connected to the common terminal COM and the other connected to the output terminal O1, which is turned on / off by a predetermined magnitude of vibration. That is, the first seismic device 10 functions as a sensor that detects vibration with a predetermined shake detection sensitivity and outputs the detection result as a pulse signal SIG1 from the output terminal O1.
[0013]
The second seismic device 11 is a switch having one connected to the common terminal COM and the other connected to the output terminal O2, and can be considered as a switch that is turned on / off by vibrations larger than the predetermined magnitude. . That is, the second seismic device 11 functions as a sensor that detects vibration with a detection sensitivity that is lower than the above sensitivity and outputs the detection result as a pulse signal SIG2 from the output terminal O2.
[0014]
Accordingly, the multistage seismic device 1 outputs a pulse signal from the first seismic device 10 when the vibration is small, and also outputs a pulse signal from the second seismic device 11 when the vibration becomes large. .
[0015]
FIG. 3 shows an output signal of the multistage seismic device 1 when there is an impact such as hitting a ball against a gas meter. That is, when a shock waveform as shown in FIG. 3 (a) is applied to the multistage seismic device 1, the first seismic device 10 generates a shock wave at a low threshold level as shown in FIG. 3 (b). A pulse signal SIG1 composed of a number of sliced pulses having a relatively short width is output. As shown in FIG. 3C, the second seismic device 11 outputs a pulse signal SIG2 composed of similar few pulses obtained by slicing the shock wave at a high threshold level.
[0016]
FIG. 4 shows an output signal of the multistage seismic device 1 when an earthquake occurs. That is, when a seismic waveform as shown in FIG. 4 (a) is applied to the multistage seismic device 1, the first seismic device 10 generates a shock wave at a low threshold level as shown in FIG. 4 (b). A pulse signal SIG1 including a sliced pulse having a relatively long width is output. The second seismic device 11 outputs a pulse signal SIG2 composed of similar pulses obtained by slicing a shock wave at a high threshold level as shown in FIG.
[0017]
The pulse signal SIG1 output from the first seismic device 10 of the multistage seismic device 1 and the pulse signal SIG2 output from the second seismic device 11 are sent to the detection circuit 2 and the time measurement circuit 3.
[0018]
The detection circuit 2 detects whether the waveform of the pulse signal SIG1 from the first seismic sensor 10 indicates the characteristics of the earthquake. Specifically, it is detected whether the pulse signal SIG1 includes a predetermined number (for example, 5) or more of pulses having a predetermined width (for example, 100 milliseconds) or more within a predetermined time (for example, 10 seconds). The detection result by the detection circuit 2 is sent to the controller 7. Conventionally, it has been determined whether or not the earthquake is based on the output of the detection circuit 2 alone. The detection circuit 2 similarly detects the pulse signal SIG2 from the second seismic device 11.
[0019]
As shown in FIG. 5, the time measurement circuit 3 measures and measures the time difference from the rise of the pulse signal SIG1 from the first seismic device 10 to the rise of the pulse signal SIG2 from the second seismic device 11. It is detected whether the time difference is equal to or longer than a predetermined time, and the detection result is sent to the controller 7.
[0020]
The shutoff valve 4 shuts off a gas supply path (not shown) in response to a control signal from the controller 7. The communication interface 5 controls communication between the controller 7 and an external device. The display unit 6 performs measurement value display and alarm display in response to a control signal from the controller 7.
[0021]
The controller 7 is composed of, for example, a microcomputer, and includes a CPU, a memory, a timer, an input / output interface (all not shown), and the like. Although details will be described later, the controller 7 controls the shutoff valve 4 based on the signal from the detection circuit 2 and the signal from the time measurement circuit 3, and measures the amount of gas used and displays it on the display unit 6. In addition, control such as displaying an alarm is performed.
[0022]
Next, the operation of the gas meter according to the first embodiment of the present invention will be described. That is, the earthquake determination method of the first embodiment will be described.
[0023]
FIG. 6 shows an output waveform of the multistage seismic device 1 in the case of an earthquake. When an earthquake occurs, the first seismic sensor 10 senses the vibration and outputs a pulse signal SIG1 as shown in FIG. Thereby, the time measuring circuit 3 starts measuring the time difference. Next, when vibration becomes large, the second seismic device 11 outputs a pulse signal SIG2 as shown in FIG. 6 (b). As a result, the time measurement circuit 3 stops measuring the time difference and the time difference is determined. In the case of an earthquake, this time difference is equal to or greater than a predetermined value, so that the time measurement circuit 3 transmits a signal indicating the detection result to the controller 7. The time measurement circuit 3 holds this time difference until the vibration ends.
[0024]
FIG. 7 shows an output waveform of the multistage seismic device 1 in the case of an impact other than an earthquake. When an impact occurs, the first seismic sensor 10 senses the vibration and outputs a pulse signal SIG1 as shown in FIG. Thereby, the time measuring circuit 3 starts measuring the time difference. Next, when the vibration increases, the second seismic device 11 outputs a pulse signal SIG2 as shown in FIG. As a result, the time measurement circuit 3 stops measuring the time difference and the time difference is determined. In the case of an impact other than an earthquake, the time difference does not exceed a predetermined value, so that the time measurement circuit 3 does not send a signal indicating the detection result to the controller 7. The time measurement circuit 3 holds this time difference until the vibration ends.
[0025]
In both cases of an earthquake and an impact, when the vibration is settled, first, the output of the second seismic device 11 is stopped, and then the output of the first seismic device 10 is stopped. When vibrations occur many times due to an earthquake, the first and second seismic devices 10 and 11 continuously output pulse signals.
[0026]
Next, when five waveforms having a long pulse width indicating the characteristics of an earthquake are generated within a predetermined time, the detection circuit 2 temporarily determines that the earthquake is occurring, and sends a signal indicating the determination result to the controller 7, otherwise. A signal indicating the judgment result is not sent.
[0027]
The controller 7 that has received the signal indicating the detection result from the detection circuit 2 and the signal indicating the determination result from the time measurement circuit 3 determines the presence or absence of an earthquake according to the flowchart shown in FIG. That is, the controller 7 first checks whether or not there is an output signal from the detection circuit 2 (step S10). Here, when it is determined that there is no output signal, that is, the waveform of the pulse signal SIG1 from the first seismic sensor 10 does not indicate the characteristics of the earthquake, the process is terminated.
[0028]
On the other hand, if it is determined that there is an output signal, that is, the waveform of the pulse signal SIG1 from the first seismic device 10 indicates the characteristics of the earthquake, then the presence or absence of the output signal from the time measurement circuit 3 is examined ( Step S11). If it is determined that there is no output signal, that is, the time difference is not greater than or equal to the predetermined time, it is recognized that the vibration is caused by an impact (step S12), and the process is terminated.
[0029]
On the other hand, when there is an output signal from the time measuring circuit 3, that is, when it is determined that the time difference is equal to or greater than a predetermined time, it recognizes that the vibration is caused by an earthquake (step S13), and sends a control signal to the shutoff valve 4. The gas supply is shut off by sending (step S14), and the process is terminated.
[0030]
As described above, according to the gas meter of the first embodiment, when the multistage seismic device 1 senses weak vibration, the pulse signal SIG1 is output from the first seismic device 10, and then when the vibration becomes strong, 2 The pulse signal SIG2 is output from the seismic device 11. At this time, the time measurement circuit 3 measures the time from the start of the first pulse of the pulse signal SIG1 to the start of the first pulse of the pulse signal SIG2. In the case of an impact with a large vibration, the time measured by the time measurement circuit 3 is very short, but in the case of an earthquake, it is generally long. When vibration continues and the detection circuit 2 detects a predetermined number or more of pulses having a predetermined width or more, which is a characteristic of seismic waves, the controller 7 temporarily determines that the event is an earthquake. If the controller 7 determines that it is an earthquake, the controller 7 can determine that it is an impact when the time measured by the time measurement circuit 3 is short, and can determine that it is an earthquake when the time is long. For this reason, there is no situation where the earthquake and impact are erroneously determined and the gas supply is shut off.
[0031]
In the conventional gas meter, even if the pulse signal is generated by an impact as shown in FIG. 7, the detection circuit 2 detects a predetermined number or more of pulses having a predetermined width or more, which is a characteristic of seismic waves, at a predetermined time. The controller erroneously determines an earthquake and controls the shutoff valve 4 to shut off the gas supply.
[0032]
The above-described gas meter controller 7 of the first embodiment can be modified to be realized by the logic circuit shown in FIG. 9 (hereinafter referred to as a first modification of the first embodiment). . The logic circuit according to the first modification of the first embodiment includes a 2-input AND gate 20, an inverter 21, and a 2-input AND gate 22. The output signal from the detection circuit 2 is sent to the first input terminals of the AND gates 20 and 22. The output signal from the time measuring circuit 3 is sent to the second input terminal of the AND gate 20 and the inverter 21, and the output signal of the inverter 21 is sent to the second input terminal of the AND gate 22.
[0033]
With the above configuration, the AND gate 20 outputs an active signal when vibration due to an impact occurs, and the AND gate 22 outputs an active signal when vibration due to an earthquake occurs. Therefore, by controlling the shutoff valve 4 with the output signal of the AND gate 22, the gas supply can be cut off only at the time of an earthquake, and the gas supply can be prevented from being cut off by vibration due to an impact. According to the first modification of the first embodiment, the controller 7 can be configured with only a small number of logic elements, and it is not necessary to use a microcomputer or the like, so that the gas meter can be made simple and inexpensive.
[0034]
(Second Embodiment)
In the gas meter according to the second embodiment, in the case of vibration due to an earthquake, attention is paid to the fact that the pulse signal output from the multistage seismic device includes a long-wavelength pulse compared to the case of vibration due to an impact. It was made. That is, even when it is determined as an impact in the gas meter of the first embodiment, if a long pulse of a predetermined length or more exists in the pulse signal output from the multistage seismic sensor 1, it is determined as an earthquake. It is what I did.
[0035]
FIG. 10 is a block diagram showing the configuration of the gas meter according to the second embodiment of the present invention. This gas meter is configured by adding a wavelength measuring circuit 8 to the gas meter of the first embodiment shown in FIG.
[0036]
Pulse signals SIG1 and SIG2 from the multistage seismic sensor 1 are input to the wavelength measurement circuit 8. The wavelength measuring circuit 8 measures the wavelengths of the input pulse signals SIG1 and SIG2, detects whether or not the wavelength is a predetermined length or more, and sends the result to the controller 7.
[0037]
In the above-described embodiment, the pulse signal SIG1 and SIG2 from the multistage seismograph 1 are input to the wavelength measurement circuit 8, but only one signal of SIG1 or SIG2 is input, and the wavelength is measured and detected. It is also possible to modify it.
[0038]
Next, the operation of the gas meter according to the second embodiment of the present invention will be described. That is, the earthquake determination method of the second embodiment will be described.
[0039]
FIG. 11 shows the vibration due to the earthquake, but similarly to the vibration due to the shock, the output waveform of the multistage seismic instrument 1 when the time difference from the rise of the pulse signal SIG1 to the rise of the pulse signal SIG2 is short is shown.
[0040]
When an earthquake occurs, the first seismic sensor 10 senses the vibration and outputs a pulse signal SIG1 as shown in FIG. Thereby, the time measuring circuit 3 starts measuring the time difference. Next, when the vibration becomes large, the second seismic device 11 outputs a pulse signal SIG2 as shown in FIG. As a result, the time measurement circuit 3 stops measuring the time difference and the time difference is determined. Even in the case of an earthquake, if the time difference is not greater than or equal to a predetermined value, the time measurement circuit 3 does not send a signal indicating the detection result to the controller 7. The time measurement circuit 3 holds this time difference until the vibration ends.
[0041]
As in the first embodiment, the detection circuit 2 detects whether the waveform of the pulse signal SIG1 from the first seismic sensor 10 indicates an earthquake characteristic, and sends the detection result to the controller 7.
[0042]
The wavelength measurement circuit 8 measures the wavelengths of the input pulse signals SIG1 and SIG2, detects whether the measured wavelength is equal to or longer than a predetermined length, and sends the detection result to the controller 7.
[0043]
In the above-described embodiment, the pulse signal SIG1 and SIG2 from the multistage seismograph 1 are input to the wavelength measurement circuit 8, but only one signal of SIG1 or SIG2 is input, and the wavelength is measured and detected. It is also possible to modify it.
[0044]
The controller 7 that has received the signal indicating the detection result from the detection circuit 2, the signal indicating the determination result from the time measurement circuit 3, and the signal indicating the detection result from the wavelength measurement circuit 8 determines whether there is an earthquake according to the flowchart shown in FIG. And the shutoff valve 4 is controlled.
[0045]
That is, the controller 7 first checks whether or not there is an output signal from the detection circuit 2 (step S10). Here, when it is determined that there is no output signal, that is, the waveform of the pulse signal SIG1 from the first seismic sensor 10 does not indicate the characteristics of the earthquake, the process is terminated. On the other hand, if it is determined that there is an output signal, that is, the waveform of the pulse signal SIG1 from the first seismic device 10 indicates the characteristics of the earthquake, then the presence or absence of the output signal from the time measurement circuit 3 is examined ( Step S11). Here, when there is an output signal from the time measuring circuit 3, that is, when it is determined that the time difference is not less than a predetermined time, it is recognized that the vibration is caused by an earthquake (step S13), and the control signal is transmitted to the shut-off valve 4. To stop the gas supply (step S14), and the process is terminated.
[0046]
If it is determined in step S11 that there is no output signal, that is, the time difference is not greater than or equal to the predetermined time, the presence / absence of an output signal from the wavelength measurement circuit 8 is next checked (step S20). Here, if it is determined that there is no output signal, that is, the pulse signal SIG1 or SIG2 from the first or second seismic device 11 does not include a pulse having a wavelength of a predetermined length or more, the impact Is recognized (step S12), and the process is terminated.
[0047]
On the other hand, if it is determined that there is an output signal, that is, the pulse signal SIG1 or SIG2 from the first or second seismic device 10 includes a pulse having a wavelength of a predetermined length or more, the earthquake (Step S13), the control signal is sent to the shutoff valve 4 to shut off the gas supply (step S14), and the process is terminated.
[0048]
As described above, according to the gas meter of the second embodiment, after it is determined that an impact has occurred once in the same manner as the gas meter of the first embodiment, the wavelength measurement circuit 8 uses the pulse signal SIG1 or When the wavelength of the SIG 2 is measured and a pulse with a long wavelength is detected, it is determined again as an earthquake, and the gas supply is shut off by controlling the shutoff valve 4. As a result, although it is a vibration due to an earthquake, it is possible to avoid erroneous determination as an impact when the time difference from the rising edge of the pulse signal SIG1 to the rising edge of the pulse signal SIG2 is short, similar to the vibration due to the shock. And the earthquake discrimination accuracy is improved as compared with the gas meter of the first embodiment.
[0049]
The above-described gas meter controller 7 of the second embodiment can be modified to be realized by the logic circuit shown in FIG. 13 (hereinafter referred to as a first modification of the second embodiment). . The logic circuit according to the first modification of the second embodiment includes a 3-input AND gate 30, an inverter 31, a 3-input AND gate 32, and an inverter 33.
[0050]
The output signal from the detection circuit 2 is sent to the first input terminal of the AND gate 30 and the first input terminal of the AND gate 32. The output signal from the time measurement circuit 3 is sent to the second input terminal of the AND gate 30 and the inverter 33, and the output signal from the inverter 33 is sent to the second input terminal of the AND gate 32. The output signal from the wavelength measuring circuit 8 is sent to the third input terminal of the inverter 31 and the AND gate 32, and the output signal from the inverter 31 is sent to the third input terminal of the AND gate 30.
[0051]
With the above configuration, the AND gate 30 outputs an active signal when vibration due to an impact occurs, and the AND gate 32 outputs an active signal when vibration due to an earthquake occurs. Therefore, by controlling the shutoff valve 4 with the output signal of the AND gate 32, the gas supply can be shut off only at the time of an earthquake, and the gas supply can be prevented from being cut off by vibration due to an impact. According to the first modification of the second embodiment, the controller 7 can be configured with only a small number of logic elements, and it is not necessary to use a microcomputer or the like, so that the gas meter can be made simple and inexpensive. .
[0052]
(Third embodiment)
The gas meter according to the third embodiment is made by paying attention to the fact that, in the case of vibration due to an earthquake, a pulse having a wavelength that is a characteristic of the seismic wave is repeatedly output compared to the case of vibration due to an impact. is there. That is, even when the gas meter according to the first embodiment is determined to be an impact, the pulse signal output from the multistage seismograph 1 is output a pulse having a wavelength that is a characteristic of the seismic wave more than a predetermined number of times. Is an earthquake.
[0053]
FIG. 14 is a block diagram showing a configuration of a gas meter according to the third embodiment of the present invention. This gas meter is configured by adding a counter circuit 9 to the gas meter of the first embodiment (see FIG. 1).
[0054]
The counter circuit 9 counts the number of times that the detection circuit 2 has detected a pulse having a predetermined width or more within a predetermined time, detects whether the count value has become a predetermined value or more, and sends it to the controller 7.
[0055]
Next, the operation of the gas meter according to the third embodiment of the present invention will be described. That is, the earthquake determination method of the third embodiment will be described.
[0056]
FIG. 15 shows the vibration caused by the earthquake, but similarly to the vibration caused by the impact, the output waveform of the multistage seismic instrument 1 when the time difference from the rising edge of the pulse signal SIG1 to the rising edge of the pulse signal SIG2 is short is shown.
[0057]
When an earthquake occurs, the first seismic sensor 10 senses the vibration and outputs a pulse signal SIG1 as shown in FIG. Thereby, the time measuring circuit 3 starts measuring the time difference. Next, when vibration becomes large, the second seismic device 11 outputs a pulse signal SIG2 as shown in FIG. As a result, the time measurement circuit 3 stops measuring the time difference and the time difference is determined. Even in the case of an earthquake, if the time difference is not greater than or equal to a predetermined value, the time measurement circuit 3 does not send a signal indicating the detection result to the controller 7. The time measurement circuit 3 holds this time difference until the vibration is finished.
[0058]
As in the first embodiment, the detection circuit 2 detects whether the waveform of the pulse signal SIG1 from the first seismic sensor 10 indicates an earthquake characteristic, and sends the detection result to the controller 7.
[0059]
The count circuit 9 counts the number of times that the detection circuit 2 has detected a pulse having a predetermined width or more within a predetermined time. When the count circuit 9 detects that the count value exceeds the predetermined value, the count result is sent to the controller 7. send.
[0060]
In the above-described embodiment, the counter circuit 9 receives the output of the detection circuit 2 to which the pulse signals SIG1 and SIG2 from the multistage seismoscope 1 are input, but only one signal of SIG1 or SIG2 is input. It is also possible to modify the detection circuit 2 so that the number of detections of the output of the detection circuit 2 is measured and detected.
[0061]
The controller 7 which has received the signal indicating the detection result from the detection circuit 2, the signal indicating the determination result from the time measurement circuit 3, and the signal indicating the detection result from the counter circuit 9 determines whether or not there is an earthquake according to the flowchart shown in FIG. Determine and control the shutoff valve 4.
[0062]
That is, the controller 7 first checks whether or not there is an output signal from the detection circuit 2 (step S10). Here, when it is determined that there is no output signal, that is, the waveform of the pulse signal SIG1 from the first seismic sensor 10 does not indicate the characteristics of the earthquake, the process is terminated. On the other hand, if it is determined that there is an output signal, that is, the waveform of the pulse signal SIG1 from the first seismic device 10 indicates the characteristics of the earthquake, then the presence or absence of the output signal from the time measurement circuit 3 is examined ( Step S11). Here, when there is an output signal from the time measuring circuit 3, that is, when it is determined that the time difference is not less than a predetermined time, it is recognized that the vibration is caused by an earthquake (step S13), and the control signal is transmitted to the shut-off valve 4. To stop the gas supply (step S14), and the process is terminated.
[0063]
If it is determined in step S11 that there is no output signal, that is, the time difference is not greater than or equal to a predetermined time, the presence / absence of an output signal from the count circuit 9 is checked (step S30). Here, when it is determined that there is no output signal, that is, the pulse signal SIG1 or SIG2 from the first seismic device 10 or the second seismic device 11 does not include a predetermined number or more of pulses indicating the characteristics of the earthquake, It is recognized that the vibration is caused by an impact (step S12), and the process is terminated.
[0064]
On the other hand, when it is determined that there is an output signal, that is, the pulse signal SIG1 or SIG2 from the first seismic device 10 or the second seismic device 11 includes a predetermined number or more of pulses indicating the characteristics of the earthquake, Recognizing that the vibration is caused by an earthquake (step S13), the control signal is sent to the shutoff valve 4 to shut off the gas supply (step S14), and the process is terminated.
[0065]
As described above, according to the gas meter of the third embodiment, after being determined to be impact once in the same manner as the gas meter of the first embodiment, the count circuit 9 includes a predetermined number or more of pulses indicating the characteristics of the earthquake. When it is detected that this is the case, it is determined again as an earthquake, and the gas supply is shut off by controlling the shutoff valve 4. As a result, although it is a vibration due to an earthquake, it is possible to avoid erroneous determination as an impact when the time difference from the rising edge of the pulse signal SIG1 to the rising edge of the pulse signal SIG2 is short, similar to the vibration due to the shock. And the earthquake discrimination accuracy is improved as compared with the gas meter of the first embodiment.
[0066]
In addition, the controller 7 of the gas meter of the third embodiment described above can be modified so as to be realized by the logic circuit shown in FIG. 17 (hereinafter referred to as a first modification of the third embodiment). . The logic circuit according to the first modification of the third embodiment includes a 3-input AND gate 40, an inverter 41, a 3-input AND gate 42, and an inverter 43.
[0067]
The output signal from the detection circuit 2 is sent to the first input terminal of the AND gate 40 and the first input terminal of the AND gate 42. The output signal from the time measurement circuit 3 is sent to the second input terminal of the AND gate 40 and the inverter 43, and the output signal from the inverter 43 is sent to the second input terminal of the AND gate 42. The output signal from the count circuit 9 is sent to the third input terminal of the inverter 41 and the AND gate 42, and the output signal from the inverter 41 is sent to the third input terminal of the AND gate 40.
[0068]
With the above configuration, the AND gate 40 outputs an active signal when vibration due to impact occurs, and the AND gate 42 outputs an active signal when vibration due to earthquake occurs. Therefore, by controlling the shutoff valve 4 with the output signal of the AND gate 42, the gas supply can be shut off only at the time of an earthquake, and the gas supply can be prevented from being cut off by vibration due to an impact. According to the first modification of the third embodiment, the controller 7 can be configured with only a small number of logic elements, and it is not necessary to use a microcomputer or the like, so that the gas meter can be made simple and inexpensive. .
[0069]
In each of the above-described embodiments, the multistage seismic device has a configuration in which the first seismic device 10 and the second seismic device 11 are integrally formed, but may be formed separately and combined with signal lines. Many modifications are possible within the scope of the claims.
[0070]
【The invention's effect】
As described above in detail, according to the present invention, by distinguishing between an earthquake and an impact, a gas meter capable of reliably shutting off gas supply only at the time of the earthquake and an earthquake determination method capable of distinguishing between an earthquake and an impact are provided. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a gas meter according to a first embodiment of the present invention.
FIG. 2 is a diagram conceptually showing the configuration of a multistage seismic device used in the gas meter according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a general relationship between a shock wave and a pulse signal output from a multistage seismoscope.
FIG. 4 is a diagram for explaining a general relationship between a seismic wave and a pulse signal output from a multistage seismoscope.
FIG. 5 is a timing chart for explaining the operation of the time measuring circuit used in the gas meter according to the first embodiment of the present invention.
FIG. 6 is a waveform diagram showing a pulse signal output by the multistage seismic device when an earthquake occurs in the gas meter according to the first embodiment of the present invention.
FIG. 7 is a waveform diagram showing a pulse signal output from the multistage seismic device when there is an impact in the gas meter according to the first embodiment of the present invention.
FIG. 8 is a flowchart for explaining the operation of a controller included in the gas meter according to the first embodiment of the present invention.
FIG. 9 is a circuit diagram showing a modification of the controller included in the gas meter according to the first embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a gas meter according to a second embodiment of the present invention.
FIG. 11 is a waveform diagram showing a pulse signal output from a multistage seismic device when an earthquake occurs in the gas meter according to the second embodiment of the present invention.
FIG. 12 is a flowchart for explaining the operation of the controller included in the gas meter according to the second embodiment of the present invention.
FIG. 13 is a circuit diagram showing a modification of the controller included in the gas meter according to the second embodiment of the present invention.
FIG. 14 is a block diagram showing a configuration of a gas meter according to a third embodiment of the present invention.
FIG. 15 is a waveform diagram showing a pulse signal output by a multistage seismic device when an earthquake occurs in the gas meter of the third embodiment of the present invention.
FIG. 16 is a flowchart for explaining the operation of a controller included in a gas meter according to a third embodiment of the present invention.
FIG. 17 is a circuit diagram showing a modification of the controller included in the gas meter according to the third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Multistage seismic device, 2 ... Detection circuit, 3 ... Time measurement circuit, 4 ... Shut-off valve, 5 ... Communication I / F, 6 ... Display part, 7 ... Controller, 8 ... Wavelength measurement circuit, 9 ... Counter circuit, 10 ... First seismic device, 11 ... Second seismic device.

Claims (3)

A seismometer that detects vibrations with different sensitivities and outputs multiple pulse signals corresponding to different sensitivities;
A detection circuit for detecting whether each pulse signal from the seismic detector includes a predetermined number or more of pulses having a predetermined width or more within a first predetermined time;
A time measuring circuit for measuring a time difference at the start of pulse output of each pulse signal from the seismic sensor,
When the detection circuit detects that a predetermined number or more of pulses having a predetermined width or more are included in the first predetermined time, the vibration is an earthquake vibration or a vibration due to an impact based on the time difference measured by the time measurement circuit. A controller for determining whether
A wavelength measuring circuit for measuring the wavelength of the pulse signal from the seismic sensor,
The controller detects that the detection circuit includes a predetermined number of pulses having a predetermined width or more within a first predetermined time, and the time difference measured by the time measurement circuit is less than a second predetermined time; and A gas meter characterized in that when the wavelength measured by the wavelength measuring circuit is equal to or longer than a predetermined length, the vibration is determined to be a vibration caused by an earthquake and the gas supply is shut off . A seismometer that detects vibrations with different sensitivities and outputs multiple pulse signals corresponding to different sensitivities;
  A detection circuit for detecting whether each pulse signal from the seismic detector includes a predetermined number or more of pulses having a predetermined width or more within a first predetermined time;
  A time measuring circuit for measuring a time difference at the start of pulse output of each pulse signal from the seismic sensor,
  When the detection circuit detects that a predetermined number of pulses having a predetermined width or more are included within a first predetermined time, the vibration is an earthquake vibration or a vibration due to an impact based on the time difference measured by the time measurement circuit. A controller for determining whether
  A counter that counts the number of times detected by the detection circuit when the pulse signal from the seismoscope includes a predetermined number of pulses having a predetermined width or more within a first predetermined time,
  The controller detects that the detection circuit includes a predetermined number of pulses having a predetermined width or more within a first predetermined time, and the time difference measured by the time measurement circuit is less than a second predetermined time; and A gas meter characterized in that, when a predetermined number or more is counted by the counter, the vibration is determined to be an earthquake-induced vibration and the gas supply is shut off. A first step of detecting vibrations with different sensitivities and outputting a plurality of pulse signals corresponding to the different sensitivities;
  A second step of detecting whether each of the pulse signals includes a predetermined number or more of pulses having a predetermined width or more within a first predetermined time;
  A third step of measuring a time difference at the start of pulse output of each pulse signal;
  When it is detected that a predetermined number of pulses having a predetermined width or more are included within the first predetermined time, whether the vibration is an earthquake vibration or an impact vibration is determined based on the time difference measured in the third step. And a fourth step
  A fifth step of measuring the wavelength of the pulse signal output in the first step,
  In the fourth step, it is detected in the second step that a predetermined number or more of pulses having a predetermined width or more are included in the first predetermined time, and the time difference measured in the third step is less than a second predetermined time. And an earthquake determination method characterized in that when the wavelength measured in the fifth step is equal to or longer than a predetermined length, the vibration is determined to be an earthquake-induced vibration and the gas supply is shut off.

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