JPS6396419A - Gas shutting-off device - Google Patents

Abstract

PURPOSE:To raise safety by providing an isolation valve equivalent resistor, drive circuit for the isolation valve equivalent resistor, and voltage detection circuit for the isolation valve equivalent resistor and supplying an electric current through the isolation valve equivalent resistor to confirm the battery voltage. CONSTITUTION:A control section 3 makes an isolation valve equivalent resistor drive circuit 11 operate to supply an electric current through the isolation valve equipment resistor 10, and to battery 8 the same load is applied when an isolation valve 7 operated an isolation valve drive circuit 4. At this time if the detection level in a voltage detection circuit 9 is set right before the operation guarantee voltage of the isolation valve 7, it is possible to confirm if the battery voltage can operate the isolation valve 7 when electric current is supplied through an isolation valve equivalent resistor 10. With this constitution it is possible to improve the safety of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a gas shut-off device that guarantees the overall safety of the gas supply.

BACKGROUND OF THE INVENTION In recent years, gas has been widely used in homes, but one mistake can lead to a gas accident, so devices that ensure the safety of gas supply are becoming more important.

An example of a conventional gas cutoff device will be described below with reference to FIG.

In FIG. 2, 1 is a gas meter, 2 is a flow rate sensor attached to the gas meter 1, 3 is a control unit whose main component is a microcomputer, 4 is a cutoff valve drive circuit, and 6 and 6 constitute the cutoff valve drive circuit 4. A resistor and a transistor, 7 a cutoff valve for a gas path 7a leading to the gas meter 1, and 8 a control unit 3
9 is a voltage detection circuit that detects the voltage of the battery 8.

The operation of the gas cutoff device configured as described above will be described below. Gas flows as shown by the arrow, and a gas flow rate signal is transmitted from the flow rate sensor 2 to the control unit 3. When there is an abnormality in the gas flow rate or when a certain flow rate continues for an abnormal time, the control unit 3 operates the cutoff valve drive circuit 4 and operates the cutoff valve 7 to cut off the gas passage 7&. In addition, the voltage detection circuit 9 has the ability of the battery 8 to drive the cutoff valve 7;
This is detected by the battery voltage. Before the voltage of the battery 8 drops and the ability to drive the cutoff valve 7 is lost, the voltage detection circuit 9 detects the drop in battery voltage, and notifies the control unit 3 that the control unit 3 shuts off the voltage via the cutoff valve drive circuit 4. The valve 7 is operated to shut off the gas passage 7a.

Problems to be Solved by the Invention However, in the conventional battery voltage check, the voltage is measured when only a small current is flowing through the control unit 3, which is the load on the battery. If there is an increase in internal resistance for some reason, the pulse characteristics of the large current deteriorate and the voltage detection circuit 9 cannot detect it even though the cutoff valve 7 loses its driving ability. In such a state, the gas cutoff device
Even if the shutoff valve 7 operates normally and the shutoff valve 7 is driven, the shutoff valve 7 will not operate and the gas passage 7a will remain open and will not function as a safety charge.

Means for Solving the Problems In order to solve the above problems, the gas cutoff device of the present invention has the following features:
It is equipped with a cutoff valve equivalent resistance which is a pseudo resistance of the cutoff valve, a cutoff valve equivalent resistance drive circuit, and a voltage detection circuit of the cutoff valve equivalent resistance.

Operation The present invention detects in a pseudo manner whether or not the battery can sustain the necessary voltage when driving the shutoff valve by operating the shutoff valve equivalent resistance drive circuit and energizing the shutoff valve equivalent resistance. can.

EXAMPLE Hereinafter, a gas cutoff device according to an example of the present invention will be described with reference to the drawings.

In FIG. 1, parts designated by numerals 1 to 8 are the same parts as those described in the conventional example. 1o is a cutoff valve equivalent resistance and has a resistance value equivalent to that of the cutoff valve 7. Reference numeral 11 denotes a cutoff valve equivalent resistance drive circuit, which energizes the cutoff valve equivalent resistance 10. 12 and 13 are resistors and transistors that constitute the cutoff valve equivalent resistance drive circuit 11.

9 is a voltage detection circuit that detects the voltage of the cutoff valve equivalent resistance 10.

The operation of the gas cutoff device configured as described above will be described below.

First, when checking the voltage of the battery 8 by the control unit 3, the cutoff valve equivalent resistance drive circuit 11 is activated and the cutoff valve equivalent resistance 1
By energizing o, the same load is applied to the battery 8 as when the shutoff valve 7 is operated by the shutoff valve drive circuit 4, and the battery 8
Check the voltage. If the detection level of the voltage detection circuit 9 is set just before the voltage of the battery 8 at this time reaches the operation guarantee voltage of the cutoff valve 7, even if the battery 8 loses its ability to drive the cutoff valve 7, the battery voltage The detection circuit 9 can detect this and drive the shutoff valve 7 to close the gas passage 7.
a can be blocked.

Effects of the Invention As described above, the present invention has the ability to maintain the terminal capacity of a battery even if the high current pulse characteristics of the battery deteriorate for some reason.
Since the battery voltage can be reliably detected before the shutoff valve can no longer be driven, the device can always be kept in a safe operating state.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a gas cutoff device which is an embodiment of the present invention, and Fig. 2 is a block diagram of a conventional example. 4...Shutoff valve drive circuit, 7...Shutoff valve, 8...Battery, 9...Battery voltage detection circuit, 1o...
Shutoff valve equivalent resistance, 11...Shutoff valve equivalent resistance drive circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person'-
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Claims (1)

[Claims] A gas flow rate sensor and a cutoff valve provided in a gas passage, a cutoff valve drive circuit that drives the cutoff valve, a control section that controls the cutoff valve in response to a signal from the flow rate sensor, and a power source for the control section. a battery, a shutoff valve equivalent resistance that is a resistance equivalent to the shutoff valve, a shutoff valve equivalent resistance drive circuit controlled by the control section, and a voltage that detects the voltage of the shutoff valve equivalent resistance and transmits it to the control section. A gas cutoff device characterized by comprising a detection circuit.