JPH06111161A - Gas leakage alarm/interruption system - Google Patents

Abstract

PURPOSE:To close a cut-off valve and to secure safety when no power is supplied to a gas leakage alarm by returning a prescribed signal from the gas leakage alarm to a gas meter at the time of turning on a power supply. CONSTITUTION:A monitoring pulse signal A is sent out from an output terminal O4 of a CPU 31 in the gas meter 21. A receiving side photocoupler 29 in the gas leakage alarm 20 is turned on/off by linking with the signal A and a signal B synchronized with the signal A is inputted to a terminal I2 of a CPU 25. The CPU 25 outputs a response pulse signal C synchronized with the signal A from its output terminal O3 to turn on/off a transmitting side photocoupler 30. Thereby a signal D prepared by inverting the signal C is inputted to an input terminal I3 of the CPU 31. Since the CPU 25 is not driven when a power supply for the alarm 20 is interrupted, the input signal D to the input terminal I3 of the CPU 31 is held at 'H' as it is. Thereby the CPU 31 outputs a closing signal from its output terminal O5 to close the cut-off valve 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak alarm shutoff system in which a gas meter with shutoff valve and a gas leak alarm are connected by two signal lines.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional gas leak alarm shutoff system. The gas meter 1 and the gas leak alarm 2 are connected to each other via a signal line 3. Gas leak alarm 2
Is composed of a gas detector 4 for detecting a gas leak, a controller 5 for controlling the whole, an alarm unit 6 for issuing a gas leak alarm, and an input / output unit 7. The input / output unit 7 is a diode connected to the photocoupler 8a of the photocoupler 8 so as to form a photocoupler 8 which is turned on when a gas leak is detected and a current path in which a current flows in a direction opposite to that when a gas leak is detected. It is composed of 9 and 9. Also, the gas meter 1
Is composed of a metering unit 10 for metering gas, a control unit 11 for controlling the whole, a shutoff valve 12, and a judgment unit 13 for judging the presence or absence of gas leakage and the presence or absence of connection.

In FIG. 3, when the gas leak alarm 2 does not detect a gas leak, the photocoupler 8 is off, so that a current path in the a direction flowing through the phototransistor 8a of the photocoupler 8 is generated. Therefore, the determination unit 13 of the gas meter 1 determines that there is no gas leak. Also, the determination unit 1
3 also periodically determines (monitors) whether or not a current path in the b direction through the diode 9 is generated when there is no gas leakage.
To do. If the current path in the b direction is not generated, it is determined that the gas leak alarm 2 is not connected, and the shutoff valve 12 is closed.

When the gas detector 4 of the gas leak alarm 2 detects a gas leak, the controller 5 turns on the light emitting diode 8b of the photocoupler 8 and the phototransistor 8a.
A current path in the a direction is generated. Then, the determination unit 13
Judges that there is a gas leak and closes the shutoff valve 12.

[0005]

However, in such a configuration, when the gas meter 1 and the gas leak alarm 2 are connected, the gas leak alarm 2 is caused by some cause.
The gas meter 1 cannot close the shutoff valve 12 even if a gas leak occurs when the power supply is stopped. In addition, for example, if the gas leak alarm 2 frequently gives a false alarm due to a miscellaneous gas such as an insecticide spray, the user intentionally turns off the power of the gas leak alarm 2 and the gas leak alarm 2 Even if is stopped, since the gas leak alarm 2 is connected on the gas meter 1 side,
The gas leak alarm 2 determines that the gas leak detection system continues to be in a ready state.

In view of the above-mentioned conventional problems, an object of the present invention is to allow the gas meter side to detect that power is not being supplied to the gas leak alarm device, and to connect the gas meter and the gas leak alarm device. However, if the gas leak alarm is not supplied with power, the shut-off valve should be closed to ensure safety.

[0007]

In order to achieve such an object, the first aspect of the present invention is to provide a gas leak alarm by connecting a gas meter with a shutoff valve and a gas leak alarm with two signal lines. Gas leak signal from the gas meter to the gas meter with shut-off valve to close the shut-off valve, and a signal for connection confirmation from the gas meter with shut-off valve to the gas leak alarm through the signal line to leak the gas. A gas leak alarm shutoff system having a function of detecting whether or not an alarm device is connected, wherein the gas meter with shutoff valve sends a monitoring signal having a polarity opposite to that of the gas leak signal to the gas through the signal line. Equipped with means to transmit to the leak alarm device regularly,
Further, the gas leak alarm device is provided with means for returning a response signal synchronized with the monitoring signal to the gas meter with a shutoff valve when the power is turned on.

According to a second aspect of the present invention, a gas meter with a shutoff valve and a gas leak alarm are connected by two signal lines, and an input / output section of the gas leak alarm is turned on when a gas leak is detected. In order to detect the presence or absence of the connection between the first photocoupler and the gas meter with the shutoff valve, the first photocoupler is formed so as to form a current path in which a current flows in a direction opposite to that in the gas leak detection.
A gas leak alarm shutoff system having a diode connected to the phototransistor of the photocoupler of
A phototransistor of a second photocoupler that is turned on / off by turning on / off a power source is connected to the diode of the input / output unit of the gas leak alarm, and the gas meter with the shutoff valve is provided with the second photocoupler. It is provided with means for detecting a voltage change in the current path due to the turning on / off of the coupler.

[0009]

In the case of the first aspect, the gas meter can periodically determine whether the gas leak alarm connected to the gas meter is under gas leak monitoring or is in a power-off state.

In the case of the second aspect, in the input / output section of the gas leak alarm, when the second photocoupler is turned on / off by turning the power supply on / off, a voltage change occurs in the current path due to the diode, and the voltage change occurs. Is detected on the gas meter side, it is possible to determine whether the gas leak alarm is under gas leak monitoring or the power is off.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows a gas leak alarm cutoff system according to a first embodiment of the present invention. The gas leak alarm device 20 and the gas meter with shutoff valve 21 are connected to each other via a signal line 22. Power is supplied to the power supply circuit 23 of the gas leak alarm device 20 from the plug 24. The power supply terminal Vcc ₁ of the CPU 25 in the gas leak alarm 20 is a power supply circuit 23, the input terminal I ₁ is a gas detection circuit 26 for detecting a gas leak, and the output terminal O ₁ is a lamp 27 that blinks when a gas leak is detected. ,
A buzzer 28 for notifying a gas leak is output to the output terminal O ₂ , and a signal from the gas meter 21 is connected to a signal line 22 to the input terminal I _2.
A receiving side photocoupler 29 for inputting via is connected. A transmission-side photocoupler 30 that outputs a gas leak signal or a response signal to the gas meter 21 via the signal line 22 is connected to the output terminal O ₃ via the resistor R ₁ .

On the other hand, the power supply terminal Vcc ₂ of the CPU 31 in the gas meter 21 is a battery 32, an input terminal I ₃ and an output terminal O ₄
An input / output switching circuit 33 is connected to. Further, a flow rate pulse generating circuit 34 is connected to the input terminal I ₄ , a shutoff valve 35 for stopping gas is connected to the output terminal O ₅ , and a display section 36 for displaying an integrated value and various information is connected to the output terminal O _6. ing.

The operation of the gas leak alarm shutoff system thus constructed will be described with reference to the signal waveform diagram of FIG. When the gas leak alarm 20 is under monitoring,
The output signal C from the output terminal O _{3 of the} CPU 25 is L. Output terminal O of CPU 31 of gas meter 21
_When the monitoring signal A, that is, the H signal having a short t ₁ time width is sent out at a constant cycle T _{1 from 4} , the receiving side photocoupler 29 of the gas leak alarm device 20 is turned on in conjunction with this signal, so A current flows through R _2, and the input terminal I of the CPU 25
_2, the signal B in synchronism with the monitoring signal A is inputted.

When the signal B is thus input to the CPU 25, the CPU 25 outputs a signal C from its output terminal O ₃ , that is, a response signal which is an H signal having a time width t ₂ synchronized with the monitoring signal A. Then, the transmission side photocoupler 30 is turned on by the H signal. When the photocoupler 30 is turned on, the input terminal I ₃ of the CPU 31 of the gas meter 21 is
A signal D obtained by inverting the response signal C is input. By inputting this signal D, the CPU 31 determines that the gas leak alarm 20 is supplied with power and is under gas leak monitoring.

Further, once the gas leak alarm device 20 detects a gas leak, a signal C, which is a continuous H signal, that is, a gas leak signal is output from the output terminal O _{3 of the} CPU 25 thereof. The coupler 30 is turned on, and the signal D input to the input terminal I ₃ of the CPU 31 of the gas meter 21 becomes a continuous L signal. And C
The PU 31 determines that there is a gas leak by inputting this L signal, and closes the shutoff valve 35. In this case, that is, when it is determined that there is a gas leak, the CPU 31 determines that the output terminal O
₄ does not output the monitoring signal having the t ₁ time width as described above.

Next, in the gas leak alarm device 20, when the plug 24 is unplugged or the power is cut off due to a power failure or the like, and the gas leak detection function does not work, the gas meter 21 C
Even if the H signal with a short t ₁ width is sent from the output terminal O _{4 of the} PU 31 as a monitoring signal in the cycle of T ₁ , the CPU 25 does not operate, and the photocoupler 30 on the transmission side also remains off.
The input signal D of the input terminal I ₃ of the CPU 31 remains L. Therefore, the CPU 31 determines that the gas leak alarm 20 is not supplied with power and outputs a closing signal from the output terminal O ₅ to close the shutoff valve 35.

FIG. 4 shows the above-described operation of the CPU 25 of the gas leak alarm device 20, and FIG. 5 shows the CPU 31 of the gas meter 21.
3 is a flowchart showing the above-mentioned operation of the. Figure 4
In, CPU 25 of the gas leak alarm 20 side determines whether gas leakage at step S _1, turns on the lamp 27 in step S ₂ Without gas leakage, also Step S ₃
In the buzzer 28 in a stopped state, to turn off the transmitting side photo coupler 30 in step S _4.

On the other hand, in FIG. 5, C on the gas meter 21 side
PU31 determines whether gas leakage signal is input in step S _10, step S ₁₁ Without its input
Then, the H signal is output from the output terminal O ₄ for t ₁ time.

In step S ₅ , the CPU 25 on the gas leak alarm 20 side determines whether the photocoupler 29 on the receiving side is on for t ₁ hours, that is, whether the input signal B at the input terminal I ₂ is H for t ₁ hours. If it is satisfied, in step S ₆ , the transmission side photocoupler 30 is turned on for t ₂ hours, so that the H signal is output from the output terminal O ₃ for t ₂ hours.

On the other hand, the CPU 31 on the gas meter 21 side is
In step S ₁₂ , it is judged whether the input signal D of the input terminal I ₃ has become L for t ₂ time, and if it is satisfied, the process returns to step S ₁₀ after T ₁ time has elapsed in step S ₁₃ .

When the CPU 25 on the gas leak alarm 20 side determines that there is a gas leak in step S ₁ , the lamp 27 blinks in step S ₇ , the buzzer 28 sounds in step S ₈ , and further in step S ₉ . The photocoupler 30 on the transmission side is continuously turned on, and a gas leak signal is transmitted. When the CPU 31 on the gas meter 21 side receives this gas leak signal in step S ₁₀ , the shutoff valve 35 is closed in step S ₁₄ , and the process returns to step S ₁₀ .

In the gas leak alarm device 20, when the plug 24 is unplugged or the power is cut off due to a power failure or the like,
Even if the H signal having a short t ₁ width is sent from the output terminal O ₄ of the CPU 31 on the gas meter 21 side in step S ₁₁ , the CPU 25 on the gas leak alarm 20 side does not operate.
_{At 12} , the L signal for t ₂ time is not input to the input terminal I ₃ of the CPU 31, so the process proceeds to step S ₁₄ and the shutoff valve 35
Close.

In the embodiment of FIG. 2, it is judged whether the gas leak alarm 20 is connected to the gas meter 21 or not when the monitoring signal A is output from the CPU 31 of the gas meter 21. It can be determined by whether or not current flows.

Next, FIG. 6 shows a gas leak alarm cutoff system according to a second embodiment of the present invention. This example is an improvement of the conventional example shown in FIG. 1. A gas leak alarm 42, which is connected to a gas meter 40 through a signal line 41, includes a gas detector 43 that detects a gas leak, and an entire gas detector 43. It is composed of a control unit 44 for controlling the above, an alarm unit 45 for issuing a gas leak alarm, and an input / output unit 46. The input / output unit 46 is
The first photocoupler 47 that is turned on when a gas leak is detected
And a second photocoupler 48 which is turned on / off by turning the power supply on / off, and a phototransistor 47a of the first photocoupler 47 so as to form a current path in which a current flows in a direction opposite to that at the time of gas leak detection. It is composed of a connected diode 49. The phototransistor 48a of the second photocoupler 48 is connected in parallel with the diode 49.

Further, the gas meter 40 comprises a metering unit 50 for metering gas, a control unit 51 for controlling the whole, a shutoff valve 52, and a judging unit 53 for judging the presence / absence of gas leakage and the presence / absence of connection. The voltage applied to the input / output unit 46 of the gas leak alarm 42 by the determination unit 53 is set to a value that does not exceed the maximum ratings of the phototransistors 47a and 48a.

When the gas leak alarm 42 does not detect a gas leak, the first photocoupler 4 of the input / output section 46 of the gas leak alarm 42 is detected.
Since 7 is off and no current path flows in the photodiode 47a of the photocoupler 47 in the a direction, the determination unit 53 determines that there is no gas leakage. Further, in this case, the determination unit 53 also determines whether or not a current path in the b direction via the diode 49 or a current path in the c direction via the phototransistor 48a of the second photocoupler 48 is generated.

When the gas meter 40 is connected to the gas leak warning device 42 and the gas leak warning device 42 is supplied with power, the second photo coupler 48 is turned on. A current path in the c direction and a current path in the b direction via the diode 49 are generated. Therefore, the determination unit 53 determines that the gas leak alarm 42 is connected and that the gas leak alarm 42 is supplied with power.

On the other hand, when power is not supplied to the gas leak alarm 42, the second photocoupler 48 is turned off, so the phototransistor 48 of the photocoupler 48 is turned off.
A current path in the c direction via a does not occur, and only a current path in the b direction via the diode 49 occurs. At this time, a voltage drop of the forward voltage VF (for example, about 0.6 V) occurs in the diode 49. On the other hand, when the photocoupler 48 is turned on, the collector-emitter of the phototransistor 48a is close to 0 V, so that the determination unit 53 is supplying power to the gas leak alarm 42 due to the difference in voltage drop. It is possible to determine whether or not.

Further, the gas meter 40 is equipped with a gas leak alarm device 4.
When 2 is not connected, a current path in the b direction via the diode 49 and a current path in the c direction via the phototransistor 48a of the second photocoupler 48 do not occur, so the determination unit 53 causes the gas leak alarm It is determined that the container 42 is not connected, and the shutoff valve 52 is closed.

Further, when the gas leak alarm 42 detects a gas leak, the first photocoupler 47 is turned on, and a current path flowing in the direction a through the photodiode 47a is generated. It is judged that there is a gas leak, and the shutoff valve 52 is closed.

[0031]

According to the present invention, in the gas meter,
Since it is possible to check whether power is supplied to the gas leak alarm connected to it, shut off when power is not supplied to the gas leak alarm even if the gas meter and gas leak alarm are connected. You can secure safety by closing the valve.

Further, the presence / absence of connection of the gas leak alarm device and the presence / absence of power supply to the gas leak alarm device can be discriminated and confirmed.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional gas leak alarm shutoff system.

FIG. 2 is a block diagram of a gas leak alarm cutoff system according to the first embodiment of the present invention.

FIG. 3 is a waveform diagram of signals in the gas leak alarm cutoff system.

FIG. 4 is a flowchart showing an operation of a CPU on the gas leak alarm side in the gas leak alarm cutoff system.

FIG. 5 is a flowchart showing the operation of the CPU on the gas meter side as well.

FIG. 6 is a block diagram of a gas leak alarm cutoff system according to a second embodiment of the present invention.

[Explanation of symbols]

 20 Gas Leak Alarm Device 21 Gas Meter 22 Signal Line 25 Gas Leak Alarm Device CPU 29 Receiving Photo Coupler 30 Transmitting Photo Coupler 31 Gas Meter CPU 35 Shutoff Valve 40 Gas Meter 41 Signal Line 42 Gas Leak Alarm Device 46 Input / Output Section 47 No. 1 Photo coupler 48 2nd photo coupler 49 Diode 53 Judgment part

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[Procedure amendment]

[Submission date] January 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Next, in the gas leak alarm device 20, when the plug 24 is unplugged or the power is cut off due to a power failure or the like, and the gas leak detection function does not work, the gas meter 21 C
Even if the H signal with a short t ₁ width is sent from the output terminal O _{4 of the} PU 31 as a monitoring signal in the cycle of T ₁ , the CPU 25 does not operate, and the photocoupler 30 on the transmission side also remains off.
The input signal D of the input terminal I ₃ of the CPU 31 remains H. Therefore, the CPU 31 determines that the gas leak alarm 20 is not supplied with power and outputs a closing signal from the output terminal O ₅ to close the shutoff valve 35.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (3)

[Claims] 1. A gas meter with a shutoff valve and a gas leak alarm are connected by two signal lines, and a gas leak signal is transmitted from the gas leak alarm to the gas meter with a shutoff valve through the signal line to close the shutoff valve. In the gas leak alarm shutoff system having a function and a function of transmitting a connection confirmation signal from the gas meter with shutoff valve to the gas leak alert device through the same signal line to detect whether or not the gas leak alert device is connected,
The gas meter with shut-off valve is provided with means for periodically transmitting a monitoring signal having a polarity opposite to that of the gas leak signal to the gas leak alarm through the signal line, and the gas leak alarm is powered by the power source. A gas leak alarm cutoff system, comprising means for returning a response signal synchronized with the monitoring signal to the gas meter with a cutoff valve through the signal line when turned on. 2. The gas leak alarm device includes a receiving-side photocoupler which is turned on / off according to the monitoring signal, and a transmission which is turned on by a gas leak signal and turned on / off according to the response signal. The gas leak alarm cutoff system according to claim 1, further comprising a side photo coupler. 3. A gas meter with a shutoff valve and a gas leak alarm device are connected by two signal lines, and a first photocoupler which is turned on when a gas leak is detected is connected to an input / output section of the gas leak alarm device. A diode connected to the phototransistor of the first photocoupler so as to form a current path for passing a current in a direction opposite to that at the time of gas leak detection to detect whether or not the gas meter with the shutoff valve is connected. In the gas leak alarm cutoff system, a phototransistor of a second photocoupler that is turned on / off by turning on / off a power source is connected to the diode of the input / output section of the gas leak alarm, and the gas meter with the shutoff valve is connected. The gas leak alarm cutoff system, further comprising means for detecting a voltage change in the current path depending on whether the second photocoupler is turned on or off.