JPS591883A - Gas shut off device - Google Patents

Abstract

PURPOSE:To decrease consumption of a battery as small as possible, by manually resetting a solenoid valve after its shut off through sensing of abnormality with a gas flow sensor, detecting electromotive force due to the manual resetting to output a resetting signal and supplying power source voltage to a resetting circuit. CONSTITUTION:A resetting detector circuit 4 is constituted by a field effect transistor (FET) 4A and a resistor 4B. The FET4A is placed in a condition in which voltage between gate sources is zero and a turn on state is provided between drain souces. If a solenoid valve 3 is operated to be manually reset, electromotive force is generated in a coil, and this causes the gate sources of the FET4A to be reversely biased, then if it exceeds a cutoff voltage, the FET4A is turned off. A microcomputer 2B generates an output O1 in a level Hi before output of a cutoff signal and an output O2 in a level Lo, not supplying power to the detector circuit 4, in this way, consumption of a battery in this circuit 4 is almost zero.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gas cutoff device for preventing scum explosions caused by various causes by opening the flow rate of scum.

Conventional structure and its problems Gas explosions occur due to abnormal gas leakage due to detachment or cracking of the rubber hose that connects the gas pipe and gas appliance, or raw gas caused by oxygen deficiency caused by long-term use of gas appliances. There is an abnormal outflow of Explosions can be prevented by detecting these factors before they lead to a gas explosion and blocking the gas flow using a blocking means provided in the gas flow path.

As this type of gas cutoff device, there is one having a configuration shown in FIG. In FIG. 3, reference numeral 1 denotes a flow rate sensor attached to the gas make 7 to detect the flow rate of gas.

This sensor includes, for example, a combination of a magnet provided in a diaphragm constituting a gas meter or a part of a link mechanism that transmits the reciprocating motion of the diaphragm to an indicator, and a reed switch that detects the position of this magnet. The gas flow rate can be determined by measuring the time from when the reed switch is turned on to when it is turned on again. Reference numeral 3 denotes a self-holding manual return type solenoid valve that combines a magnet and an electromagnetic coil provided in the gas flow path, and shuts off the gas flow path in response to a cutoff signal from the control unit 6. This electromagnetic valve is designed to self-maintain in an open state by the force of a magnet, thereby reducing consumption of the battery used as the device's power source.

Further, the shutoff operation is performed when the self-holding state is released as the electromagnetic force generated by passing a current through the electromagnetic coil overcomes the force of the magnet holding the valve in the open state. In this way, once it is in the cutoff state, it will not be turned into the open state by the force of the magnet alone.
There is no longer a need for current to flow. To open the
Open the valve manually and position it so that it can be held by the magnetic force. The control unit 6 receives the signal from the flow rate sensor 1, processes this signal according to a predetermined processing procedure, determines whether or not to shut off, and if the shut-off conditions are satisfied, issues a shut-off signal. Output to solenoid valve 3. As a processing procedure, for example, it is determined whether or not the current meter detected by the current sensor 1 has been flowing at a constant value for a predetermined period of time. This means that the device has been used for a longer period of time than the normal operating time, and such a condition indicates some abnormality and outputs a shut-off signal.Since this type of device uses a self-holding manual return type solenoid valve, the control unit After the valve outputs the shutoff signal, it is necessary to make the control unit recognize whether the valve is in the shutoff state or not.

For this reason, for example, a magnet is installed in the movable part of a solenoid valve, and a reed switch is installed at a position where the solenoid valve is turned on when it is open and turned off when it is closed. Conventionally, it has been done to make the This will now be explained in more detail using FIG. 4. 2 is a control circuit which converts the on/off state of the reed switch of the mouse sensor 1 into a voltage "u HIZ It Lo" signal using two resistors.

The microcomputer 2B receives this signal and processes it according to a predetermined processing procedure stored as a program. If the cutoff condition is satisfied, the microcomputer 2B outputs a cutoff signal, which causes the transistor 2
C turns on, current flows through the electromagnetic coil 3C of the electromagnetic valve 3,
The waste flow path is blocked. 4' is a return detection circuit, which turns on and off the reed switch 4C by using a resistor 4B to control the voltage l Hi.
The signals are converted into ll and ll protection signals and input to the microcomputer 2B. In the cut-off state, reed switch 4C
is OFF, and the output of the return detection circuit 4' is ``0''. If the solenoid valve 3 is opened again by manual return operation, the reed switch 4C is turned on, and the output of the return detection circuit 4' is ``0''. As a return signal, the microcombi
1-Year 2B input, Microcombi j.

2B is a battery capable of recognizing that the electromagnetic fP3 is in an open state; 5 is a battery as a power source for the device.

The disadvantage of such conventional devices is that when the valve is open (4, battery 5, resistor 4B, 4B, leakage switch 4, current is constantly flowing 71), which accelerates battery consumption.

OBJECTS OF THE INVENTION An object of the present invention is to provide a scum cutoff device that eliminates the drawbacks of the conventional devices described above and reduces battery consumption as much as possible.

Structure of the Invention The structure of the present invention enables the solenoid valve to be manually reset after the gas flow meter sensor detects an abnormality and shuts off the solenoid valve, and detects the electromotive force generated when the solenoid valve is manually reset. It outputs a return signal and supplies the power supply voltage to the return detection circuit after a predetermined period of time from the end of the interruption UI (No. N output).

Embodiment FIG. 1 is a circuit diagram of an embodiment of the present invention. 1.4 is a return detection circuit, which is composed of a FET 4A and a resistor 4B. FE
T4A has a gate-source voltage YGs of zero V,
The region between the drain and source is in an on state. When the solenoid valve 3 is manually reset, an electromotive force is generated in the solenoid coil. The electromotive force reverse biases between the gate and source of FET4A, and its cutoff voltage VOFF
When it becomes larger than , FET4A is turned off. The microcomputer 2B controls the power supply of the return detection circuit 4. This will be explained using the timing chart of FIG. Before t1 when the microcomputer 2B outputs the cutoff signal, its output 01 is "I H1'!", the transistor 2C is off, and its output 02 is "I H1'!"
Therefore, power is not supplied to the return detection circuit 4, and as a result, the battery consumption of the return detection circuit 4 is almost zero. As soon as the cutoff condition is satisfied at time t1, my black combination coater 2B
sets the output 01 to I L01' until time t2, turns on the transistor 2C, causes current to flow through the electromagnetic coil 3C, and cuts off the electromagnetic valve 3.
transitions from on to word-off, but at this time, the solenoid valve 3's koi/l/3 G's? lj, a voltage is generated in the direction that keeps the current flowing. That is, until time t3, a voltage in the opposite direction to the voltage up to time t2 is generated. Since this voltage has the same polarity as the voltage due to the electromotive force generated when the solenoid valve 3 is manually reset, immediately after time t2, the output 02 of the micro combi coater 2B becomes faithful, and the power supply of the reset detection circuit 4 is supplied, the back electromotive force generated between time t2 and t3 is detected, and this is output to the microcomputer 2B as a return detection signal.

In order to avoid such a problem, after the back electromotive force disappears, that is, from time t4 after a predetermined period of time has elapsed from the interruption signal output end time t2, the microcombi,
B inhibits its output 02.

As a result, power is supplied to the recovery detection circuit 4.

Until time t5 when the manual return operation is performed, the gate-source voltage YGs of FET 4A is zero V, so the four FETs are turned on and the input 12 of the micro combi coater 2B is
+l LO'l. When the solenoid valve 3 is manually reset at time t5, an electromotive force is generated in the solenoid coil at time t6.
1, and as a result, the 4 FETs are manually inputted to the OFF L-microcomputer 2B's human power 12 as a 'claw' return signal.As a result, the microcomputer 2B recognizes the return operation and exits at time t7. , its output 02 is turned off, and the power supply to the recovery detection circuit 4 is stopped.

Effects of the Invention As detailed above, in the present invention, the return detection circuit of the solenoid valve is configured by a combination of F'ET and a resistor, and there is no need to worry about using a magnet or a reed switch. There is no need to provide a magnet or a 'J-1-' switch, and the entire device can be made smaller. Since the control circuit supplies power to this recovery detection circuit after a predetermined period of time has elapsed after the output of the cutoff signal ends, it is possible to cut off (malfunctions that may occur when outputting a new signal), +Ir, and further, Since power is supplied only during the period during which recovery is to be detected, there is no unnecessary consumption of the battery.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram of a gas cutoff device according to an embodiment of the present invention, Fig. 2 is an operation timing diagram of Fig. 1, and Fig. 3 is a schematic configuration diagram of a conventional gas cutoff device. , FIG. 4 is a circuit diagram of FIG. 3. 1...Flow M sensor, 2...Production 1 circuit, 3...
...Self-recording holding manual return f (Solenoid valve, 4...
Return detection circuit, 5...Battery. Daimisakito's name Riki) Riju Satoshi Nakao Katana and 1 other person 1st country 9 1++ shi2L3 t<'&s
c6 b7 @3 Figure 4

Claims (1)

[Claims] a flow rate sensor that detects the gas flow rate; and a p that outputs a cutoff signal when a signal from the flow rate sensor satisfies a predetermined condition.
An rlJ control circuit, a self-holding manual return type solenoid valve that receives the mJ cutoff signal and shuts off the gas flow path, and detects an electromotive force generated when the solenoid valve is manually reset and sends a return signal to the control circuit. A gas cutoff device includes a return detection circuit that outputs an output, and the control circuit supplies power and voltage to the return detection circuit after a predetermined time from the end of outputting the cutoff signal to the solenoid valve.