JPH0735904B2 - Gas leak alarm shutoff system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak alarm cutoff system, and more particularly to a state in which a gas leak alarm output has occurred, and gas shutoff in this state and shutoff after release of the alarm output. The present invention relates to a device that further improves safety by displaying states in different display cycles.

<< Prior Art >> A gas leak alarm shutoff system is a system that automatically shuts off gas by driving a solenoid shutoff valve in conjunction with a gas leak detector in a room to maintain safety.

As one of the methods of this alarm system, there is a shutoff method shown in FIG.

This shutoff method comprises an alarm device 1 and a solenoid type gas shutoff valve 2 connected to the output end of the alarm signal 1.
As shown in the time chart in the figure, the alarm 1
When the gas sensor therein detects gas, a pulse output is continuously generated from the alarm device 1, an alarm buzzer sounds intermittently, and at the same time, an alarm lamp blinks.

When this state continues for a predetermined time, the shutoff pulse signal is output from the alarm device 1, the gas shutoff valve 2 is driven, and the valve is closed.

As a result, when the gas leak is eliminated, the alarm operation of both the alarm lamp and the buzzer is stopped.

Therefore, if the shut-off valve 2 is manually restored thereafter, the shut-off valve 2 will be opened and the gas supply path will be opened again.

As another blocking method, there is a method shown in FIG.

In the system shown in the figure, a switch 3 for alarm operation which opens / closes in conjunction with the opening / closing operation of the shut-off valve 2 is built in, and when the shut-off valve 2 is closed by an alarm output from the alarm device 1,
The switch 3 opens the circuit and consequently changes the period of the buzzer and the alarm lamp to warn that the shut-off valve 2 has been activated.

<Problems to be solved by the invention> However, the former method only knows whether or not there is a gas leakage state, and the latter method has advantages and disadvantages, although it is possible to confirm the interrupted state but it is not known whether or not the gas leakage state has been released. .

In other words, in the case of the former method, the alarm action stops when the gas leakage actually stops even if the gas is actually shut off.Therefore, whether the gas leakage is stopped by the shut-off valve or another alarm is issued by closing the cock, for example. It is not possible to determine whether it has stopped.For example, even if the cock of the gas appliance was closed in response to an alarm, the shutoff valve was actually operating, and as a result, no gas was released when the cock was opened again. It has been a cause of problems such as presuming a failure without grasping it.

On the other hand, in the latter method, whether or not the shut-off valve has been activated is output by changing the alarm cycle depending on whether the gas leak is in the alarm state or the shut-off state. Compared with the method described above, there is an advantage that it can be immediately confirmed whether or not the shutoff valve 2 is in operation.

On the contrary, this advantage leads to the drawback that it is possible to confirm the shutoff state, but it is not known whether the gas leak alarm has been released.If the shutoff valve return operation is performed without confirming the alarm release, it becomes rather dangerous. .

In other words, in this method, even if the gas cutoff valve is activated, the gas already released remains filled in the room unless ventilation is performed in the room where the alarm is placed. It is not possible to know whether or not the alarm condition is continuing.

The present invention has been made based on the above background, and an object thereof is to make it possible to simultaneously judge whether or not a shutoff valve is operating and whether or not a gas leak alarm is on standby. It provides a shutoff system.

<< Means for Solving the Problems >> The present invention, which achieves the above object, provides a gas leak alarm device that outputs a shutoff valve closing signal when a built-in gas sensor detects a gas leak, and this closing signal A gas leak alarm shutoff system comprising a shutoff valve for shutting off a gas line by closing a shutoff valve built therein when an input is made, wherein the shutoff valve is provided with a switch for opening and closing in response to opening and closing of the shutoff valve. The gas leak alarm device includes a gas alarm device main circuit that outputs a shutoff valve drive command signal, an alarm signal, and an alarm medium drive signal when the gas sensor detects a gas leak, and the gas alarm device. A shutoff valve drive circuit that is connected to a main circuit and the shutoff valve, and outputs a shutoff signal to the shutoff valve with a predetermined delay time when the shutoff valve drive command signal is input; and the gas alarm. Connect to the main circuit, An alarm medium driven in a first drive mode by an alarm medium drive signal, a valve opening / closing confirmation circuit which is connected to the switch, and confirms the open / closed state of the shutoff valve by opening / closing the switch to output a signal, An alarm signal is input from the main circuit of the alarm device, the valve opening / closing confirmation circuit, and the alarm medium, and an alarm signal from the gas alarm device main circuit is input. When inputted, the alarm medium is connected to a first control circuit for driving the alarm medium in a second drive mode different from the first drive mode, the valve opening / closing confirmation circuit and the alarm medium to confirm the valve open / close state. And a second control circuit for driving the alarm medium in a third drive mode different from the first and second drive modes when a shutoff valve closing confirmation signal is input from the circuit. The alarm medium is It is driven in the first drive mode by the alarm medium drive signal from the alarm device main circuit. When the shutoff valve performs the shutoff operation in this state, it is driven in the second drive mode by the first control circuit. When the alarm signal is no longer output from the gas alarm main circuit due to the release of the gas leak state, the second control circuit is driven in the third drive mode.

In the first to third driving modes, the first driving mode is intermittent driving in a predetermined cycle, the second driving mode is continuous driving, and the third driving mode is intermittent driving in the first driving mode. It is possible to perform intermittent driving with a longer cycle.

<< Operation >> According to the gas leakage warning shutoff system of the present invention, the first drive mode is the intermittent drive of the predetermined cycle, the second drive mode is the continuous drive, and the third drive mode is the first drive mode. When the continuous drive is performed for a period longer than the intermittent period in (1), the alarm medium continuously generates an alarm output at a constant period by the sensor output when the gas leaks. After that, when the shutoff valve is driven to shut off the gas supply source, an alarm output is continuously generated to indicate that a gas leak alarm is being issued and that the shutoff valve is also operating.

When the gas leakage stops and the sensor no longer detects it due to gas dissipation, the output cycle of the alarm medium changes to a cycle different from the above two statuses, and only the shutoff valve warns that it is shutting off. .

<< Example >> An example of the present invention will be described below in detail with reference to the drawings.

1 and 2 show a gas leak alarm shutoff system according to the present invention.

In the figure, this system comprises a gas leak alarm device 10 arranged near the gas equipment side, and a shutoff valve 12 connected to the alarm device 10 and arranged at a gas supply source to open and close a flow path. .

The alarm device 10 is supplied with power through an AC power plug 16 and a transformer 18, and also has a gas alarm main circuit 14 in which a gas sensor (not shown) and the like are built-in, and the AC power plug 1
6, the power is supplied through the transformer 18, the shutoff valve drive circuit 20 connected to the output end of the drive command signal of the main circuit 14 and the continuous pulse signal generated from the main circuit 14 to turn on and Two alarm media, which generate an alarm sound and are connected in parallel to the output terminals of the AND circuit 26 and the flip-flop circuit 28, are an alarm lamp 22 and an alarm buzzer 24.

The gas shutoff valve 12 is provided with a solenoid 30 that is driven by receiving a shutoff pulse signal from the shutoff valve drive circuit 20, and a valve element that is provided at the tip of a plunger (not shown) provided in the solenoid 30 and faces the gas flow path. There is. In addition, a switch 32 that opens and closes according to the operating state of the solenoid 30 is provided in the shutoff valve 12.
Is provided, the circuit is closed and turned on in a normal state, and is opened and turned off when the solenoid 30 is excited, that is, when a cutoff pulse is applied.

One end of the switch 32 is connected to one end of the solenoid 30, and the other end is connected via the valve opening / closing confirmation circuit 34.
It is connected to the input terminals of the AND circuit 26 and the flip-flop circuit 28.

The other input end of the AND circuit 26 is connected to the alarm output end of the main circuit 14.

The output states of the lamp 22 and the buzzer 24 differ depending on the ON / OFF state of the switch 32 and the generation state of the alarm output from the main circuit 14.

That is, when the switch 32 is closed (ON), the transistor Tr1 in the confirmation circuit 34 is OFF and the transistor Tr2 is kept ON.

Therefore, one of the input terminals of the AND circuit 26 is grounded by turning on the transistor Tr2 and turned off.
The transistor Tr4 of 6 turns off. When the switch 32 is opened (OFF), the transistor Tr1 is turned ON, the transistor Tr2 is turned OFF, and one input end of the AND circuit 26 is connected to the power supply of the flip-flop circuit 28. At this time, since the high-level alarm signal is output from the main circuit 14,
A drive signal is output from the AND circuit 26, and the transistor Tr4 is driven (ON) to continuously drive the lamp 22 and the buzzer 24.

Further, the flip-flip circuit 28 is a relaxation oscillation circuit using a PUT, and a capacitor provided inside the circuit.
A transistor Tr3 is connected via C1 and PUT, and the transistor Tr3 can be driven to drive the lamp 22 and the buzzer 24. The flip-flop circuit 28 is adapted to intermittently drive at a cycle corresponding to the time constant determined by the capacitor C1 and the resistor R _3, R _1, R ₂ warning signal is OFF state (OFF) from the main circuit 14 .

Next, the operation of the system having the above configuration will be described with reference to the time chart of FIG.

First, the sensor output temporarily rises when the power is turned on,
This is to prevent an alarm from being generated by an energization ringing prevention circuit (not shown) provided inside the main circuit 14, and to indicate that the alarm is being activated by lighting the alarm lamp 22, and to stabilize the sensor after a predetermined time has elapsed. The lamp 22 is also turned off and the standby state is set.

When a gas leak occurs from the standby state, the sensor output rises, and when the output exceeds the threshold value, a continuous pulse signal is output from the main circuit 14 to the alarm lamp 22 and the buzzer 24,
The lamp 22 blinks in a continuous short cycle, and the buzzer 24 continuously sounds in the same cycle.

At the same time, a drive command signal is output from the main circuit 14 to the shutoff valve drive circuit 20. In this state, the alarm signal from the main circuit 14 is input to one input end of the AND circuit 26, but the transistor Tr2 is ON while the shutoff valve 12 is not open (OFF). , The other side is OFF,
Since the transistors Tr3 and Tr4 are also turned off, the lamp 22 and the buzzer 24 are both maintained in a state where a continuous alarm signal is generated by the continuous pulse signal from the main circuit 14.

Thereafter, the drive circuit 20 receiving the drive command signal outputs a cutoff pulse with a predetermined time delay, and the solenoid 30 is driven to cut off the gas flow path.

The drive of the solenoid 30 causes the switch 32 to open (OFF) the circuit, which causes the transistor T in the confirmation circuit 34 to turn off.
Turn on r1. When the transistor Tr1 is turned on, the transistor Tr2 is turned off. As a result, both inputs of the AND circuit 26 become high level and the drive signal is output, and the transistor Tr2 is
The drive 22 (ON) causes the lamp 22 and the buzzer 24 to continuously light up and ring continuously.

When the gas leak state is released in this state, the continuous pulse output of the main circuit 14 disappears and the alarm signal is not input to the AND circuit 26, so the transistor Tr4 is turned off and the continuous alarm state is released. , Display that the gas leak has been released.

However, OFF state of the transistor Tr2 is persisted, and outputs a relatively long period of the signal from the flip-flop circuit 28 at a cycle corresponding to the time constant defined as the capacitor C1 by the resistor _{R 3, R 1, R 2} , transistor Tr3 Is intermittently turned on, and the lamp 22 and the buzzer 24 are intermittently lit and sounded at a relatively long cycle by the drive of the shutoff valve 12 in the gas leak release state.
The operating status of is displayed.

Since this alarm display suggests that the gas source may be opened with the gas leakage stopped, if the shutoff valve 12 is manually returned in response to this, the switch 32 is closed again and the transistor Tr1 OFF, the transistor Tr2 is turned ON, and the driving of the flip-flop circuit 28 is stopped.
And the buzzer 24 ends the alarm operation.

<Effect> As described in detail in the above embodiments, according to the present invention, the alarm medium continuously generates the alarm output at a constant cycle by the sensor output when the gas leaks. After that, when the shutoff valve is driven and the gas supply source is shut off, an alarm output is continuously generated, indicating that a gas leak alarm is in progress and that the shutoff valve is also operating. Then, when gas leakage stops and the sensor no longer detects it due to gas dissipation, etc., the output cycle of the alarm medium changes to a cycle different from the above two states, and only the shut-off valve is shut off. Give an alarm.

Therefore, according to the present invention, it is possible to display which state is in accordance with the three-stage output change of the alarm medium, so that it is possible to immediately determine whether or not the shut-off valve is shut off, and the gas is still present. There is no risk of erroneous operation such as opening the gas source when the gas is full, and safety can be further improved.

In the embodiment described above, the alarm medium (alarm lamp 22 and buzzer 24) is continuously driven at a constant cycle as the first drive mode in the state where the gas leakage is detected, and the shutoff valve 12 supplies the gas. In the shut-off state, the valve is continuously driven as the second drive mode, and the shut-off valve 12 is in the shut-off state, but gas leakage is stopped, and the third drive mode is intermittently driven in a long cycle. The first to third drive modes are not limited to these modes, and any drive mode may be used as long as the three drive modes are different.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a gas leak alarm shutoff system of the present invention, FIG. 2 is a circuit block diagram showing an electrical configuration of the system, FIG. 3 is a time chart of the system, and FIG.
5 and 5 are a schematic explanatory view and a time chart of a conventional gas leak warning system. 10 …… Gas leak alarm 12 …… Shutdown valve 14 …… Gas alarm main circuit 20 …… Shutdown valve drive circuit 22 …… Alarm lamp (alarm medium) 24 …… Alarm buzzer (alarm medium) 26 …… AND circuit (First alarm output means) 28 …… Flip-flop circuit (second alarm output means) 30 …… Solenoid 32 …… Switch 34 …… Valve opening / closing confirmation circuit

Claims (2)

[Claims] 1. A gas leak alarm for outputting a shut-off valve closing signal when a built-in gas sensor detects a gas leak,
A gas leak alarm shutoff system comprising a shutoff valve that shuts off a gas line by closing a shutoff valve that is built in when this shutoff signal is input. A switch for opening and closing is provided, and the gas leak alarm has a gas alarm main circuit that outputs a shutoff valve drive command signal, an alarm signal, and an alarm medium drive signal when the gas sensor detects a gas leak. A shutoff valve drive circuit which is connected to the gas alarm main circuit and the shutoff valve and outputs a shutoff signal to the shutoff valve with a predetermined delay time when the shutoff valve drive command signal is input. An alarm medium connected to the gas alarm main circuit and driven in a first drive mode by the alarm medium drive signal, and connected to the switch to check the open / closed state of the shutoff valve by opening / closing the switch. Output signal An open / close check circuit is connected to the gas alarm main circuit, the valve open / close check circuit, and the alarm medium, and an alarm signal from the gas alarm main circuit is input and cut off from the valve open / close check circuit. A first control circuit for driving the alarm medium in a second driving mode different from the first driving mode when a valve closing confirmation signal is input; a valve opening / closing confirmation circuit and the alarm medium; A second drive mode which is connected and drives the alarm medium in a third drive mode different from the first and second drive modes when the shutoff valve closing check signal from the valve open / close check circuit is input. A control circuit is provided, the alarm medium is driven in a first drive mode by an alarm medium drive signal from the gas alarm main circuit, and in this state, when the shutoff valve performs a shutoff operation, The first control circuit causes the second The second driving circuit is driven in the third driving mode when the warning signal is not output from the gas alarm main circuit due to the subsequent release of the gas leakage state. Gas leak alarm shutoff system. 2. The first drive form is an intermittent drive of a predetermined cycle, the second drive form is a continuous drive, and the third drive form is an intermittent drive in the first drive form. The gas leakage alarm cutoff system according to claim 1, wherein the system is an intermittent drive with a long cycle.