JPH0755052A - Gas shutoff device - Google Patents

Abstract

PURPOSE:To detect opening and closing states without influencing upon opening and closing work of a cutoff valve. CONSTITUTION:Immediately after opening and closing of a cutoff valve 1 is carried out and others, a limited driving circuit 8 separately provided from a driving circuit 4 of the cutoff valve 1 is driven, a transient response waveform by limiting resistance 9 is detected by a transient response detection part 12, and its result is detected by a control part 16. That is, by checking a difference of equivalent inductance 3 of opening and closing states of the cutoff valve 1 in accordance with the transient response of the separately provided limiting resistance 9 and equivalent inductance 3, opening and closing of the cutoff valve 1 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shutoff device for preventing gas accidents.

[0002]

2. Description of the Related Art A conventional gas shutoff device of this type is shown in FIG. In FIG. 2, 1 is a shutoff valve, 2 and 3 are equivalent resistances and inductances of the shutoff valve 1, 4 is a drive circuit for closing the valve, 5 and 6 are resistors and transistors forming the drive circuit,
7 is a flow rate measuring means for measuring the flow rate corresponding to the passing gas,
28 is an oscillating circuit driven in response to a signal from the control unit 14,
Reference numerals 29, 20, 21, 12 constitute an oscillation circuit 28, 29 is a capacitor that resonates with the equivalent inductance 3 of the shutoff valve 1, 22 is a control unit for controlling oscillation, and 20, 2
1 is a transistor and resistor for feedback, 23 is frequency measuring means for measuring the frequency of the oscillation circuit 28, 24 is driving the drive circuit 4 when the flow rate signal of the flow rate measuring means 7 has an abnormal flow rate pattern, and a shutoff valve 1, a control unit that shuts off the gas passage and operates an oscillation circuit 28 to detect the open / closed state of the valve to detect the oscillation frequency to detect the open / closed state; 17 is a power source for the entire apparatus; 16 is a control unit 24; This is an informing means for informing the outside of the valve open / closed state.

In order to detect the open / closed state of the shutoff valve 1 with such a configuration, the following procedure is used. As shown in FIG. 3, the cutoff valve 1 has a different equivalent inductance 3 because the position of the plunger (iron core) is different in the open / closed state. The controller 24 drives the oscillator circuit 28 as needed. The oscillation circuit 28 oscillates at a different frequency depending on the open / close state of the shutoff valve 1 due to the difference in the equivalent inductance 3. The oscillation frequency is measured by the frequency measuring means 23. Control unit 24
Is notified by the notification means 26 according to the result of the flow rate measurement means 7.

[0004]

However, in such a gas shutoff device, since the open / closed state of the shutoff valve 1 is detected by the resonance frequency of the equivalent inductance 3 and the capacitor 29, the oscillation circuit 28 and the frequency measuring means. Since a complicated circuit such as 23 is required, it is necessary to consider the stability of oscillation before detection, a large amount of current is consumed, and a power source is burdened as a gas cutoff device.

On the other hand, in general, there is a method of detecting a transient current waveform as a method that is simple in terms of circuit and consumes less current in addition to the method of measuring by frequency, but as shown in FIG. When the switch circuit is connected to the drive circuit 4 in series, there is no problem in detecting the open / closed state, but when the shutoff valve 1 is driven, the current detection resistor limits the current, so the valve cannot be closed.

Therefore, the gas shut-off device of the present invention is fast in measurement, has a small current, and does not close when the shut-off valve is closed or does not close when the open / closed state is detected. The purpose is to detect the open / closed state of the shutoff valve without affecting the open / close.

[0007]

In order to achieve the above object, a gas shutoff device of the present invention comprises a flow rate measuring means for measuring a flow rate corresponding to a passing gas flow rate, a shutoff valve for shutting off a gas passage, and the shutoff. A drive circuit that opens and closes a valve, a limiting drive circuit that energizes the shutoff valve via a limiting resistor separately from the drive circuit, and detects a transient response waveform of the shutoff valve during driving of the limiting drive circuit. When a transient flow detection unit that outputs a result and an abnormal flow rate pattern are detected by the flow rate measurement unit, the drive circuit is driven, the shutoff valve is opened and closed, and the limit drive circuit is driven as necessary, It is provided with a control unit for detecting the result of the transient response waveform of the transient response detection unit and a battery as a power supply.

[0008]

With the above-described means, the gas shutoff device of the present invention drives the limiting drive circuit provided separately from the drive circuit of the shutoff valve immediately after the shutoff valve is opened / closed, and the transient due to the limiting resistance is caused. The response waveform is detected by the transient response detection unit,
The control unit detects this result.

That is, the opening / closing of the shutoff valve is detected by looking at the transient response waveforms of the limiting resistance and the equivalent inductance which are provided separately for the difference in the equivalent inductance of the open / close state of the shutoff valve. As a result, the measurement is quick, the current is small, and the shut-off valve does not close when it is closed or does not close when the open / closed state is detected. The open / closed state of the valve can be detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the gas shutoff device of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is a shutoff valve, 2 and 3 are equivalent resistances and inductances of the shutoff valve 1, 4 is a drive circuit for closing the valve, 5 and 6 are resistors and transistors forming the drive circuit, and 7 is Flow rate measuring means for measuring the flow rate corresponding to the passing gas, 8 is a limiting drive circuit for energizing the shut-off valve 1 through a limiting resistance, 9, 10, 11 constitute a limiting drive circuit 8, and 9 is a shut-off valve. 1 is a limiting resistance that is inserted in series with the equivalent inductance 3; 10 and 11 are transistors and resistors that constitute a drive circuit that energizes the equivalent inductance with the limiting resistance 9; and 12 is a transient response of the cutoff valve 1 during driving of the limiting drive circuit 8. Transient response detector that detects the waveform and outputs the result,
Reference numerals 13, 14, 15 constitute a transient response detector 12, 13 is a comparator whose input is the potential across the shut-off valve 1, and 14 is a divider from the collector side when the transistor 10 of the limiting drive circuit 8 is driven. And 15 to form a reference potential of the comparator 13, 15 to be a pull-up resistor for output of the comparator, 16 to drive the drive circuit 4 when the flow rate signal of the flow rate measuring means 7 has an abnormal flow rate pattern, and to shut off the shut-off valve 1 The control unit that drives the limiting drive circuit 8 as necessary to shut off the gas passage and detects the open / closed state of the valve and detects the result of the transient response waveform of the transient response detection unit 12, and 17 is the entire device. A power source, 18 is an informing unit for informing the valve opening / closing state from the control unit 16 to the outside.

When the limiting drive circuit 8 is driven immediately after the shutoff valve 1 is opened / closed, the transient response waveform of the input of the comparator 13 of the transient response detector 12 has a difference in the equivalent inductance 3 in the open / closed state of the shutoff valve 1. Therefore, as shown in FIG. 5, the transient response waveform corresponds to the open / closed state of the shutoff valve 1. The limiting resistance 9 is R, the equivalent resistance 2 of the shutoff valve 1 is r, the equivalent inductance 3 is L, the battery voltage is E, and the transistor 10 has Vc.
If esat is neglected, the voltage Vo across the shutoff valve 1 is determined by the transient response characteristics of the resistors R and r and the inductance L.

[0013]

[Equation 1]

[0014] The reference potential of the comparator 13 is V
If ref is set, the input transient response waveform of the comparator 13 becomes
Assuming that the time that is smaller than the reference potential Vref is T1 and T2 respectively when the shutoff valve 1 is in the open / closed state, T1 <T2 from the transient response characteristics of the resistors R and r and the inductance L. The open / closed state of the shutoff valve 1 can be detected by detecting this time difference by the control unit 16. Control unit 18
Is notified by the notifying means 16 according to the result of the flow rate measuring means 7.

According to this structure, since the limiting resistor 9 is not provided in the drive circuit 4 for opening and closing the shutoff valve 1, the open / closed state of the shutoff valve 1 is detected without affecting the current when the shutoff valve 1 is driven. be able to. Further, since the limiting drive circuit 8 limits the current in advance by the limiting resistor 9, the shutoff valve 1 does not open and close erroneously even if the driving time of the limiting drive circuit 8 becomes long.

The timing for detecting the open / closed state may be other than immediately after the shutoff valve 1 is opened / closed, or immediately after impact detection if there is impact detection means or the like. The current state of the shutoff valve 1 can be detected from the outside of the gas shutoff device by means of communication with the outside.

[0017]

As is apparent from the above invention, the gas shutoff device of the present invention shuts off by looking at the transient response waveforms of the limiting resistance and the equivalent inductance which are provided separately for the difference in the equivalent inductance of the open / close state of the shutoff valve. The open / close of the valve is detected, the circuit is simpler than the method of detecting the difference in the oscillation frequency, the measurement is quick, the current is small, and the burden on the battery power supply of the gas shutoff device can be reduced. Further, the open / closed state of the shutoff valve can be detected without affecting the open / closed state of the shutoff valve without being closed when the shutoff valve is closed or closed when the open / closed state is detected.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a gas shutoff device according to an embodiment of the present invention.

FIG. 2 is a conventional functional block diagram.

[Fig. 3] (a) Magnetic circuit diagram of shutoff valve open state (b) Magnetic circuit diagram of shutoff valve closed state

FIG. 4 is a block diagram of a conventional general transient response detection circuit.

[Fig. 5] (a) Transient response waveform when shutoff valve is closed (b) Transient response waveform when shutoff valve is open

[Explanation of symbols]

 1 Shut-off valve 4 Drive circuit 8 Limit drive circuit 12 Transient response detection unit 16 Control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Takemura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masaki Yamaguchi, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A flow rate measuring means for measuring a flow rate corresponding to a passing gas flow rate, a shutoff valve for shutting off a gas passage, a drive circuit for opening and closing the shutoff valve, and a limiting resistor separately from the drive circuit. A limit drive circuit that energizes the cutoff valve, a transient response detection unit that detects a transient response waveform of the cutoff valve during driving of the limit drive circuit, and outputs the result, and an abnormal flow rate pattern by the flow rate measurement unit. When the drive circuit is detected, the control circuit drives the drive circuit, opens and closes the shutoff valve, drives the limit drive circuit as needed, and detects the result of the transient response waveform of the transient response detection section; And a gas shutoff device.