JPH0246998B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an interlocking gas leak detector that closes a gas cutoff valve provided in a gas flow path in response to a gas leak signal generated when the gas leak detector detects a gas leak. It concerns a shutoff system.

Conventionally, as shown in Fig. 1, this type of system electrically connects a gas leak detection alarm 1 and a shutoff valve 2 via a controller 3, so that the alarm 1 detects leaking gas and There is a known device that automatically closes the gas flow path and stops the gas supply if the alarm continues to be issued for more than a certain period of time to prevent further gas leakage.

The controller 3 closes the cutoff valve 2 in response to the detection of gas leakage by the alarm 1, thereby preventing further gas leakage and ensuring safety. However, the conventional controller 3 only generates a single shutoff signal after a predetermined period of time in response to the occurrence of a gas leak signal. Therefore, if the valve body of the shut-off valve 2 is mechanically stuck and cannot be switched by the single shut-off signal mentioned above, there will be no chance to close the shut-off valve 2 after that, allowing gas leakage to continue and become dangerous. This resulted in an extremely serious safety problem.

Therefore, the conventional gas cutoff valve has a switch that opens and closes in conjunction with the opening and closing of the valve, and a valve close signal is input to the controller via a signal line depending on the state of the switch, and the gas cutoff valve is cut off from the controller. For example, in the Jichi Kaisho system, when a valve close signal is not input from the gas cut-off valve even after a signal is output, a cut-off signal is repeatedly output to ensure the gas cut-off valve is closed, thereby improving safety. This method is proposed by Japanese Patent No. 58-138195.

However, in conventional systems, including this proposed one, if the signal line that transmits the cutoff signal from the controller to the gas cutoff valve is disconnected for some reason, the gas cutoff valve is shut off in response to the detection of a gas leak. A problem arises in that the gas cutoff valve cannot be shut off at the critical moment.

Therefore, in view of the above-mentioned conventional problems, the present invention further improves safety by automatically shutting off the gas cutoff valve when the signal line for transmitting the cutoff signal to the gas cutoff valve is disconnected. The purpose of the present invention is to provide a gas leak detector interlocking shutoff system that achieves the following.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic diagram of an embodiment of the gas leak detector interlocking shutoff system according to the present invention. The illustrated system includes three gas leak detectors 10, a gas cutoff valve 20a of a gas meter section 20, a control device 30 according to the present invention, and the like.

When gas leaks, the gas leak detector 10 detects the gas at one-quarter or less of the lower explosive limit, displays a lamp, and outputs a gas leak signal to the control device 30. It also detects an intentional act (self-inflicted act such as suicide) on the sensor section of the gas leak detector 10, and outputs a self-inflicted act signal to the control device 30.

The control device 30 receives a gas leak signal and a self-inflicted act signal from the gas leak detector 10, issues a warning with a buzzer and a lamp in response to the gas leak signal, and outputs a cutoff signal to the gas cutoff valve 20a. Further, the gas cutoff valve 20a can be manually shut off using the manual cutoff switch 30p on the control device 30. Furthermore, it is also possible to output an external output signal that can be linked to an external device O such as a central monitoring panel in an apartment complex or the like. Shutoff valve 20a
receives a cutoff signal from the control device 30, and turns on the valve 20a.
and outputs a valve close signal for displaying the shutoff valve on the control device 30.

In order to accomplish the above, the control device 30 has a number of terminals on its back as shown in FIG. First, there are nine terminals: three 24V terminals 30a and three terminals 30b that supply power to the three gas leak detectors 10, and three signal terminals 30c that accept input signals from the three gas leak detectors 10. They are arranged in one row. In addition, three terminals 3 are connected between the gas cutoff valve 20a and a 3-core signal cable.
0d, 30e, 30f and two terminals 30g, 30h to which the auxiliary contacts of the breaker are connected.
and two terminals 30i and 30j for outputting a signal corresponding to the input signal from the gas leak detector 10 to the external device 40.
0a to 30c are arranged in a row at a certain distance apart. Furthermore, a power terminal 30k is provided at the bottom for drawing in AC100V power to the device.

As can be seen in Figure 2, the surface of the control device 30 includes a power lamp 30l, an alarm lamp 30m, a shutoff lamp 30n, which are composed of light emitting diodes, and an automatic lamp that is activated when a gas leak occurs when it is turned to the monitoring side. A manual switch 30p is provided which is configured with a waveform switch that selects whether to shut off the gas cutoff valve in the event of a misbehavior or to shut off the cutoff valve immediately when it is turned to the manual side. It houses a control circuit that controls the following.

By the way, each of the above gas leak detectors 10 is
DC24V from terminals 30a and 30b of control device 30
Voltage is supplied to operate, 6V when gas leak is not detected, 12V when gas leak is detected (gas leak signal),
When a flash in the gas sensor section or a break in the connection line between the gas sensor section and the control device 30 is detected, a voltage signal of 0V (self-damage signal) is generated and applied to the corresponding terminal 30c.

Further, as shown in FIG. 4, the gas cutoff valve 20a includes a valve operating circuit 21 and a valve interlocking magnet 2.
3, and a reed switch 24 which is turned on and off by the magnet 23, and which is turned on when the valve is opened and turned off when the valve is closed. The valve actuation circuit 21 has terminals 30d' and 30e' connected to the terminals 30d and 30e of the control device 30 via connecting wires, and a voltage of about 6V.
a 20V discrimination circuit 21a that discriminates when the voltage between the terminals 30d' and 30e' reaches approximately 20V;
It consists of a 0V discrimination circuit 21b that discriminates when the voltage between the terminals 30d' and 30e' reaches 0V, and a valve opening/closing circuit 21c. The circuit 21c includes a switch element SW1 triggered by the 20V voltage discrimination by the 20V discrimination circuit 21a and the 0V discrimination circuit 21.
It has a switch element SW2 which is triggered by the determination of 0V voltage by b, and conduction of SW1 causes a large current to flow in the direction of the solid line arrow in the valve drive coil L to open the valve, and conduction of SW2 charges the capacitor C. The charge is discharged and a small current is passed through the valve drive coil L in the direction of the dotted arrow to close the valve.

Note that the 0V voltage and 20V voltage applied from the control device 30 between the terminals 30d' and 30e' are connected to the cutoff valve 20a.
The signal is applied to the valve to close and open the valve, and is applied only for a predetermined short period of time as a cutoff signal and a valve return signal, respectively.
A voltage of 6V is applied between 0d' and 30e'.

Next, the configuration of the control device 30 will be explained with reference to FIG. 5, in which the same parts as those in FIGS. 2 to 4 are denoted by the same reference numerals.

31 in the figure is the detector power supply circuit, and the terminal 30
Supplied to k via a breaker (not shown)
AC100V is stepped down by a transformer T and applied.
Rectify and smooth AC to obtain 24V DC, and apply this to terminal 3.
It has the ability to supply to three detectors 10 from 0a and 30b. 32 is a short circuit protection circuit, and terminal 30
This protects the power supply circuit 31 from being damaged due to a short circuit between a and 30b.

33 is a power supply circuit that supplies DC power to the control circuit of the device, and is supplied to the terminal 30k.
AC 100V is stepped down by a transformer T, and the DC obtained by rectifying and smoothing the AC is supplied from the part indicated by the black arrow to each part in the circuit indicated by the same arrow. This rectified and smoothed DC is made into a constant voltage and is supplied from the part indicated by the white arrow to each part in the circuit indicated by the same arrow.

34 is a backup power supply circuit, which has a large capacity charging capacitor _C1 that is charged via a diode D by the rectified and smoothed DC. The backup power stored in this capacitor _C1 is approximately 6V, and is supplied from the part indicated by the half-black arrow to each part of the circuit indicated by the same arrow. This circuit is necessary to shut off the valve by the manual switch 30p after the breaker is turned off, or to shut off the valve 5 minutes after the breaker is shut off. Note that the same diode D as above is used to prevent backflow.

35 is a shutoff valve output circuit, in which a switching transistor circuit _Q1 connected between the backup power supply 34 and the terminal 30d is turned on and off by a signal applied to its base, and when it is on, the switching transistor circuit Q1 is connected between the backup power supply 34 and the terminal 30d. A voltage of approximately 6V is output between the terminals, and the voltage between terminals 30d and 30e is 0V when turned off. This 0V voltage becomes a cutoff signal that closes the cutoff valve 20a.

Reference numeral 36 denotes a valve return pulse output circuit, in which a switching transistor circuit _Q2 connected between the power supply circuit 31 and the terminal 30d is turned on and off by a signal applied to its base. Outputs a voltage of approximately 20V during 30e. This 20V voltage becomes the valve opening signal.

37 is a gas leak signal discrimination circuit, and the detector 1
When the voltage signal applied from 0 to terminal 30c is equal to or higher than the discrimination voltage of approximately 7.5V by Zener diode ZD, it is determined that there is a gas leak signal, and the output of inverter 37a is changed from H to L level accordingly. do.

38 is a self-inflicted act signal discrimination circuit, and the detector 1
Voltage signal applied to terminal 30c from 0V
It is determined that it is a self-inflicted act signal, and accordingly, the output of the NAND circuit 38a is changed from L to H level, and the output of inverter 38b is changed from H to L level.

39 is an external device output circuit, and normally the output of the NAND circuit 38a in the discrimination circuit 38 is at L level, and the transistor circuit _Q3 is turned on.
Approximately set by transistor circuits Q ₄ and Q ₅
A constant voltage of 6V is output from terminals 30i and 30j through the transistor circuit _Q3 . When determining the self-inflicted act signal, the output of the NAND gate 38a is at H level and the transistor circuit _Q3 is turned off.
The output voltage of terminals 30i and 30j becomes 0V. When the gas leak signal is determined, the output of the inverter 37a becomes L level and the transistor circuit _Q3 is turned on, so the approximately 12V voltage applied to the terminal 30c at this time is directly applied to the transistor circuit _Q3.
The signals are output from terminals 30i and 30j through the terminals 30i and 30j.

40 is a buzzer drive circuit, 41 is a buzzer driven by the circuit, and the circuit 40 is such that the output of the inverter 37a of the circuit 37 is L when determining a gas leak signal.
By forming a belt, the internal oscillation circuit oscillates, causing the buzzer 41 to sound.

42 is a power supply interruption detection circuit, and when the power supply to the device is interrupted due to a power outage or tripping of a breaker,
The output of the inverter 42a changes from L to H level.

43 is a breaker disconnection detection circuit, in which the auxiliary terminal 44 of the breaker that supplies power to the device (turns on when the breaker is turned on) connects to the terminal 30 as shown by the dotted line.
When connected between g and 30h, auxiliary terminal 4
4 is on, the inverter 42a
grounding the output of circuit 42, disabling the function of circuit 42. Then, by turning off the auxiliary terminal 44, the capacitor _C2 is charged by the backup power supply, and the output of the inverter 43a changes from the H level to the L level.

When the auxiliary terminal 44 is not connected to the terminals 30g and 30h, the output of the inverter 42a becomes H level due to the power supply being cut off, and accordingly, the output of the inverter 43a changes from H level to L level.

45 is a 60 second delay circuit, and the circuit 37 determines whether there is a gas leak signal and the output of the inverter 37a goes from H to L level, or the circuit 38 determines whether there is a self-inflicted act signal and the inverter 38b
When the output of inverter 4 changes from H to L level,
The output of 5a changes from L level to H level, thereby charging capacitor C ₃ through resistors R ₁ and R ₂ . When the charge level of capacitor _C3 exceeds a predetermined value, programmable union transistor PUT1 turns on and charges the capacitor.
Rapidly discharge the charging charge of C ₃ through resistor R ₂ ,
This turns PUT1 off again. At this time, the output of the inverter 45b goes from H to L level when PUT1 is turned on, and goes to L level when PUT1 is turned off.
The signal goes from H level to output an L level pulse.

When PUT1 is turned off, capacitor _C3 is charged again, but the time constant of _R1 , _R2 , and _C3 is set so that it takes about 40 seconds for PUT1 to turn on again. One L level pulse is generated at the output of inverter 45b every approximately 40 seconds until the capacitor _C3 is no longer charged.

Reference numeral 46 denotes a pulse generation circuit composed of a monostable multivibrator (one-shot circuit) 46a, and when the L-level pulse generated at the output of the inverter 45a is applied to the trigger input of the one-shot circuit 46a, Its output, which is normally at H level, becomes L level at a certain time, and this is inverted by inverter 46b and output as an H level pulse. The output of this pulse generating circuit 46 is connected to the base of the transistor circuit _Q1 of the cutoff valve output circuit 35, and while the H level pulse is maintained, the transistor circuit Q1 is
Turn off _Q1 . As a result, the terminals 30d,
The voltage applied to the shutoff valve 20a from 30e changes from 6V to 0V during the pulse period and returns to 6V again.

47 is an answer back circuit, and the cutoff valve 20a
The reed switch 24 connects terminal 3 as shown by the dotted line.
0f is connected. The reed switch 24 is on when the cutoff valve 20a is open, but is turned off when the cutoff valve 20a is closed by application of 0V voltage from the cutoff valve output circuit 35. When reed switch 24 is turned off, the output of inverter 47a changes from H level to L level.

The output of this inverter 47a is connected via a diode D to a connection point between resistors R ₁ and R ₂ of the circuit 45. Therefore, the output of the inverter 47a is L.
When the voltage reaches the level, the capacitor _C3 is no longer charged, an L level pulse is no longer generated at the output of the inverter 45b, and the one-shot circuit 46a is no longer triggered.

By the way, if the line connecting reed switch 24 to answer back circuit 47 is disconnected for some reason, even if cutoff valve 20a is open, inverter 47a will be disconnected in the same way as if the valve were closed. The output is at L level. Therefore, even if a gas leak or self-damage signal is determined, the capacitor _C3 will not be charged. In this case, the output of the inverter 47a is
Since the level is applied to one input of the NAND circuit 46c, the inverter 4
Depending on the H level of the output of 5a, the NAND circuit 46
Inverter 46 connected to the other input of c
When the output of d becomes L level, the NAND circuit 46c
The output of inverter 45b changes from L to H level, and in response, an L level pulse is generated at the output of inverter 45b. Therefore, the one shot circuit 46a is triggered by this L level pulse and generates an L level pulse at its output. This pulse is inverted to turn off the transistor circuit _Q1 for the duration of the pulse, so that a shut-off signal is generated, albeit only once.

48 is a 5-minute timer circuit composed of a counter circuit, and its reset input is connected to the output of the breaker trip detection circuit 43, and is in a reset state while its input level is at the H level, and is at the L level.
When the level is reached, the reset is canceled and the program starts. If there is no reset input for 5 minutes, an L level pulse is generated at its output and applied to the trigger input of the one shot circuit 46a. Therefore, a cutoff signal can be generated 5 minutes after the power supply is cut off or the breaker is cut off.

49 is a 40 second delay circuit, which waits approximately 40 seconds after the gas leak and self-injury signals disappear and the normal state returns.
This is a circuit that creates a 40 second delay to return the shutoff valve 20a after a second. When the output of inverter 45a changes from H level to L level due to the return to the normal state, the output of inverter 46d changes from L level to H level, and transistor circuit _Q6 is turned on. As a result, capacitor _C3 is charged via resistors _R3 and _R4 , and when the level exceeds a predetermined value after about 40 seconds, PUT2 is turned on. By turning on PUT2, inverter 4, which had been at L level,
The output of 9a temporarily becomes H level.

50 is a one-shot circuit 50a and an inverter 5
This is a pulse generation circuit consisting of 0b, and when a high level pulse is input from the delay circuit 49 to the trigger input of the one shot circuit, its output remains high for about 2 seconds.
Generates a pulse that becomes the level. This pulse is inverted by inverter 50b and applied to the base of transistor circuit Q ₂ of valve return pulse output circuit 36, thereby inverting transistor circuit Q ₂
turns on for 2 seconds. By this, terminal 30
A valve opening signal of approximately 20V is supplied to the shutoff valve 20a through the terminals d and 30e, and the shutoff valve 20a is opened. By opening this valve, the reed switch 24 is turned on again.

51 is a manual cutoff switch circuit, and when the switch 30p is turned off, the output of the inverter 51a becomes L.
Once the level is reached, it is applied directly to the pulse generation circuit 46 through the capacitor _C4 . Therefore, as soon as the switch 30p is turned off, a shutoff signal is generated and the shutoff valve 20a is opened. However, if the valve does not close for some reason, since the output of the inverter 45a is at H level at this time, the one-shot circuit 46a continues to be triggered until the valve closes. When this switch 30p is returned to its original on state, a valve return pulse is generated in the same manner as in the above case.

An initial reset circuit 52 resets the one-shot circuits 46a and 50a at the start of energization to prevent unnecessary valve shutoff signals and valve return signals from being generated.

As explained above, according to the present invention, the cutoff signal generated by the controller in response to the gas leak signal generated by the gas leak detector changes the predetermined voltage that is always at the first value to the second predetermined voltage that is lower than the predetermined voltage. A gas cutoff valve that closes the gas flow path in response to a cutoff signal generated by the controller is connected to a valve drive coil and a predetermined value of the first value that the controller always outputs. a charging means that is charged by a voltage;
comprises a voltage discrimination circuit for discriminating a voltage lower than the value of , and a switch means that is turned on according to the voltage discrimination by the voltage-specific circuit, and the charge stored in the charging means is discharged by turning on the switch means. It has a valve actuation circuit that causes the valve to close by flowing through the valve drive coil.

Therefore, when the signal line between the controller and the gas cutoff valve is cut off, the voltage discrimination circuit determines a voltage lower than the second value and turns on the switch means, discharging the charge stored in the charging means. It is now possible to automatically close the valve by flowing it through the valve drive coil, further improving safety.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing a conventional gas leak detector interlocking shutoff system, Fig. 2 is a diagram schematically showing a system according to the present invention, and Fig. 3 is a rear view of a control device used in the system of the present invention. , FIG. 4 is a circuit diagram of a gas cutoff valve used in the system of FIG. 2, and FIG. 5 is a circuit diagram showing details of the circuit configuration of a control device used in the system according to the present invention. 10... Gas leak detector, 20a... Gas cutoff valve,
24...Reed switch, 45...1 minute delay circuit, 4
6...Pulse generation circuit, 47...Answer back circuit,
_C3 ...capacitor, PUT1...programmable union transistor, L...valve drive coil, C...capacitor (charging means), 21...valve operation circuit, 21b...0V discrimination circuit (voltage discrimination circuit), SW2...switch element (switch means).

Claims (1)

[Scope of Claims] 1. A gas leak detector that detects a gas leak and generates a gas leak signal, a controller that generates a cutoff signal in response to the gas leak signal generated by the gas leak detector, and a gas flow path. a gas cutoff valve provided in the controller, the gas cutoff valve having a valve close signal generating means for generating a valve close signal in response to the valve closing, and closing the gas flow path in response to a cutoff signal generated by the controller; In the gas leak detector interlocking shutoff system, the shutoff signal is repeatedly outputted by the controller until the controller receives a valve close signal from the valve close signal generating means, the shutoff signal being generated by the controller in response to the gas leak signal. is composed of a voltage signal in which a predetermined voltage that is always at a first value is lowered to a second value lower than the predetermined voltage, and the gas cutoff valve is connected to a valve driving coil and the voltage signal that the controller always outputs. A charging means that is charged with a predetermined voltage of a first value, a voltage discrimination circuit that discriminates a voltage lower than the second value, and a switch means that is turned on in response to voltage discrimination by the voltage discrimination circuit. A gas leak detector interlocking shutoff system comprising: a valve actuation circuit that causes the electric charge stored in the charging means to flow through the valve drive coil to close the valve when the switch means is turned on.