JP2503948Y2 - Abnormality detection circuit of the shutoff valve in the built-in shutoff valve gas meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a gas meter with a built-in shutoff valve, and more particularly to a gas meter provided with a circuit for detecting an error motion of the shutoff valve.

(Prior Art) A gas meter with a built-in shutoff valve is equipped with a bidirectional solenoid type shutoff valve at a gas inlet port, a microcomputer (hereinafter simply referred to as a microcomputer) for determining an abnormality, gas flow rate detection means, and the like. By inputting a signal from the detection means or an external gas leak alarm to the microcomputer, and if it judges that there is an abnormality, a cutoff command signal is output to the driver circuit, and the driver circuit outputs a cutoff pulse to the solenoid to cut off the signal. Close the valve and let it self-hold in this state.

At the same time, the abnormality is reported through the user or the telephone line.

(Problems to be Solved by the Invention) In the above configuration, the shutoff valve may operate to close the flow path even when the shutoff command signal is not output from the microcomputer.

In other words, these mechanisms are driven by a built-in power source such as a lithium battery built into the gas meter, and since the battery capacity must be maintained until the time to replace the gas meter, the driving force of the solenoid that constitutes the shutoff valve is extremely high. Is set to a small value, and in the normal state, the shutoff valve is held in the released state by the mechanical balance between the attractive force of the magnet and the spring pressure.

Therefore, if external mechanical vibration or shock, or a large negative pressure at the time of gas passage, the mechanical balance may be lost and the shutoff state may occur automatically.

On the other hand, since there is no means to detect this kind of malfunction in the microcomputer, this kind of alarm or display is not made and the cause of the interruption is not clear, so not only does the user feel distrust, but also the security management of the center. It was also affecting.

In particular, this type of microcomputer may have a built-in logic that needs to collect data for a long time, such as "Continuous usage time exceeded" or "Micro flow continuation alarm". If the cutoff occurs, these logics will be cut off, and the discovery of abnormalities such as gas leakage will be delayed.

This invention solves the above problems, and by detecting the mechanical malfunction of the shutoff valve itself, it is possible to eliminate the above-mentioned adverse effects, and a shutoff valve abnormality detection circuit in a shutoff valve built-in gas meter. Is intended to provide.

[Means for Solving the Problems] (Means for Solving the Problems) In order to achieve the above object, the present invention is directed to a shutoff valve provided in a gas meter and a driver circuit for applying a shutoff direction exciting current to a coil of the shutoff valve. And a control means for instructing a closing signal to the driver circuit, wherein a shutoff valve built-in gas meter is provided with first means for detecting a voltage induced in a coil by movement of a plunger of the shutoff valve, and the control means. Second detection means for detecting a command signal output from the second detection means, and output means for outputting the signal from the first detection means to the control means as an abnormal signal when there is no detection signal from the second detection means. It is a thing.

(Operation) When the drive pulse is applied to the cutoff valve, or when the cutoff valve is mechanically operated without the drive pulse applied, an induced electromotive force is generated in the cutoff valve coil, and the first detection means To detect. On the other hand, the second detection means constantly monitors the command signal from the control means, and when the command signal from the control means is not output, only when the detection signal from the first detection means is output, The control means is made to recognize that the cutoff is abnormal.

(Embodiment of the Invention) Hereinafter, one embodiment of the invention will be described in detail with reference to the drawings.

FIG. 1 shows a shutoff valve drive circuit provided with an abnormal shutoff detection circuit according to the present invention.

In the figure, 1 is a nozzle provided inside the gas meter at the gas inlet port, 2 is a gas cutoff valve arranged facing the nozzle 1, and 3 is a cutoff or return pulse to a coil 2a of the gas cutoff valve 2. The driver circuit 4 to be applied is a control means for instructing an open / close signal to the driver circuit 3 through the open / close ports 4a and 4b, that is, the CPU 5 is an abnormality detection circuit, and the output of the abnormality cutoff detection circuit 5 is the CPU 4 Input to interrupt port 4b.

The shut-off valve 2 is a bidirectional solenoid provided with a valve element at the tip of the plunger. The plunger is bidirectionally held by the attraction force of a magnet and a balance of a spring, etc., and a current supplied to the coil 2a. The magnetic force of the magnet is reduced or strengthened according to the direction of forward movement to move forward or backward, and when the energization is cut off thereafter, the magnet is held at the forward or backward position.

The abnormality detection circuit 5 is a first detection means for waveform shaping the voltage generated between the connection line AA ′ connecting the driver circuit 3 and the coil 2a, that is, the waveform shaping circuit 6, the driver circuit 3 and the opening / closing port. Open signal line L connecting 4a and 4b
1 and the second detection means connected to the closed signal line L2, that is, the OR circuit 7, the inverted output of the OR circuit 7 and the signal of the waveform shaping circuit 6 are input, and the output end is connected to the interrupt port 4b. The output means connected, that is, the AND circuit 8 is provided.

In the above-mentioned configuration, in the abnormal processing due to the normal flow rate abnormality, gas leakage, etc., the shut-off command signal is output from the closed port 4b when the CPU 4 determines that it is abnormal, and in response to this, the driver circuit 3 outputs the shut-off pulse. The shut-off valve 2
Closes the nozzle 1 and self-holds in this state.

Further, when the abnormality is restored, a return command signal is output from the open port 4a, and in response to this, a return pulse signal is output from the driver circuit 3, whereby the plunger is retracted by the backward current flowing in the coil 2a and shut off. The valve 2 opens the nozzle 1 and holds itself in this state.

In the above operation mode, the voltage generated between A-A 'is detected and the waveform shaping circuit 6 outputs "1" to one of the AND circuits 8. However, since the inverted output of each of the OR circuits 7 is "0", the output of the AND circuit becomes "0", and the CPU 4 continues the normal abnormality processing routine.

Also, due to mechanical vibration, shock, or negative pressure,
When the shutoff valve 2 performs the shutoff operation or the release operation in a state where the power is not supplied, the following detection operation is performed.

The bidirectional solenoid described above is normally in the released state by its nature, and in this state, it is often shut off by mechanical vibration, shock, or negative pressure when passing gas, and is automatically released from the shutoff. Although it is extremely rare, it can be applied to either case.

That is, when the plunger moves due to the mechanical malfunction, an electromotive force having a waveform shown in FIG. 2 is generated in the coil 2a according to Fleming's law, and as a result, a voltage is generated between A and A'and accordingly, the same as above. The waveform shaping circuit 6 outputs "1" to one of the AND circuits 8.

The output of the open / close ports 4a and 4b is "0", and as a result, the inverted output from the OR circuit 7 becomes "1", and "1" is output from the AND circuit 8 and the CP is output through the interrupt port 4c.
It will be input to U4.

Then, the CPU 4 receives this signal and performs another interruption logic, for example, a temporary interruption such as a logic that needs to collect data for a long time such as the above-mentioned "continuous use time over" and "fine flow rate continuation alarm". In addition to executing the continuous operation of the program whose logic is obstructed by, it is possible to execute processing operations such as re-release and re-interruption.

[Effects of the Invention] As described in detail above with reference to the embodiments, the abnormality detection circuit of the shutoff valve in the gas meter with a built-in shutoff valve according to the present invention can detect a mechanical malfunction of the shutoff valve itself. Various harmful effects due to mechanical malfunction can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram showing the electrical construction of a shutoff valve abnormality detection circuit in a shutoff valve built-in type gas meter according to the present invention, and FIG. 2 is a graph showing a waveform of an electromotive force generated in a coil. 2 ... Shutoff valve 2a ... Coil 3 ... Driver circuit 4 ... CPU (control means) 5 ... Abnormality detection circuit 6 ... Waveform shaping circuit (first detection means) 7 ... OR circuit (second detection means) 8 ... AND circuit (Output means)

Claims (1)

(57) [Scope of utility model registration request] 1. A built-in shut-off valve including a shut-off valve provided in a gas meter, a driver circuit for applying an exciting current in a shut-off direction to a coil of the shut-off valve, and control means for issuing a close signal to the driver circuit. Type gas meter, first means for detecting a voltage induced in the coil by movement of the plunger of the shutoff valve, second detecting means for detecting a command signal output from the control means, and the second detection An abnormality detection circuit for a shutoff valve in a shutoff valve built-in gas meter, comprising an output means for outputting the signal from the first detection means to the control means as an abnormality signal when there is no detection signal from the means.