JPH0247338Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas cutoff valve control device that controls shutoff and return of a gas cutoff valve using a charging voltage of a capacitor.

[Conventional technology]

A conventional device of this type is shown in FIG. In the figure, 1 is a gas cutoff valve, 2 is a drive circuit that controls the opening and closing of the gas cutoff valve 1, and 7 is a cutoff capacitor charger that charges and discharges the cutoff capacitor _C1 in response to a cutoff control signal that is output in the event of an emergency such as a gas leak. A circuit 8 is a switch circuit whose opening and closing are controlled by a cutoff control signal, and is provided between the cutoff capacitor charging circuit 7 and the drive circuit 2. Reference numeral 9 denotes a recovery capacitor charging circuit 10 that charges and discharges the recovery capacitor C ₂ in accordance with a recovery control signal, and a charge detection circuit that detects the charging voltage of the recovery capacitor C ₂ of the charging circuit and outputs a recovery signal; 11 indicates the detection circuit 10;
This is a return pulse switch circuit that outputs a return pulse signal to the drive circuit 2 based on the output of . The cutoff capacitor charging circuit 7 includes a diode D ₂ and a resistor R ₁₀ .
and cut-off capacitor _C1 . Recovery capacitor charging circuit 9 consists of resistor R ₁₁ and recovery capacitor C ₂
The charge detection circuit 9 consists of a Zener diode ZD ₂ connected in series between the recovery capacitor C ₂ , a resistor R ₁₂ and a transistor Q whose base is connected to the connection point thereof and whose collector is connected to the resistor R ₁₃ . Consists of ₃ .

In such a configuration, in an emergency such as a gas leak, the cutoff control signal goes to L level, turns off the diode _D2 of the cutoff capacitor charging circuit 7, discharges the cutoff capacitor _C1 , and closes the switch circuit 8. This discharge current drives the drive circuit 2 through the switch circuit 8 and shuts off (closes) the gas cutoff valve 1. H when the cutoff control signal is no longer output.
level, the switch circuit 8 opens and the diode _D2 is turned on, charging the cutoff capacitor _C1 with the time constant of the resistor _R10 . At this time, the cutoff valve 1 maintains the cutoff state.

On the other hand, the cutoff control signal is not output (H level),
When the gas cutoff valve 1 is in the cutoff state, when the return control signal goes to H level, the return capacitor _C2 becomes a resistor.
It is charged with a time constant of _R11 . Charging detection circuit 10
Then, when this charging voltage rises to a predetermined voltage, the Zener diode ZD ₂ turns on, and the transistor
Q ₃ turns on. As a result, the input level of the return pulse switch circuit 11 changes from the H level to the L level, and a return pulse is output to the drive circuit 2 to return the cutoff valve 1 (open).

The time constant of the cutoff capacitor charging circuit 7 is set to be smaller than the time constant of the recovery capacitor charging circuit 9, and is set so that the charging of the cutoff capacitor _C1 is completed before the charging of the recovery capacitor _C2 is completed. Priority is given to the shutoff operation. That is, after the gas cutoff valve 1 is shut off, the period from the generation of the return control signal to the output of the return pulse is made longer than the period from when the return control signal can be input, to ensure that the return pulse is supplied to the drive circuit 2. I'm trying to make it happen.

FIG. 3 shows another conventional example, in which 12 is a cutoff signal output circuit, 13 is a cutoff pulse output circuit that outputs a cutoff pulse from the output circuit 12, and the structure of the cutoff capacitor charging circuit 7 in FIG. It is similar to 14 is a timer circuit operated by the output circuit 12, and 15 is a return pulse output circuit that inputs the timer circuit 14 and a return control signal.

In such a configuration, when a cutoff control signal is output from the cutoff signal output circuit 12, a cutoff pulse is outputted from the cutoff pulse output circuit 13 to close the gas cutoff valve and operate the timer circuit 14 for a predetermined period of time. While the timer circuit 14 is in operation, its output is input to the return pulse output circuit 15 to make the output circuit 15 inactive, so that no return pulse is output even if a return control signal is output. As a result, while the timer is operating, the gas cutoff valve is maintained in the cutoff state regardless of the generation of the return control signal. Further, when the cut-off control signal is no longer output from the cut-off signal output circuit 12, it is set so that charging of the charging capacitor of the cut-off pulse output circuit 13 is completed while the timer is operating.

[Problem that the invention attempts to solve]

In the conventional configuration shown in FIG. 2, if the diode _D2 , resistor _R10 , etc. of the cutoff capacitor charging circuit 7 is disconnected, charging of the cutoff capacitor _C1 may not be completed. In this case, when the recovery control signal is outputted thereafter, the recovery capacitor _C2 of the recovery capacitor charging circuit 9 is charged, and after a predetermined period of time, the transistor _Q3 of the charging detection circuit 10 is turned on.
A return pulse signal is output. As a result, the gas cutoff valve 1 opens, and even if a gas leak occurs thereafter, the cutoff capacitor _C1 is not charged, so no discharge current flows through the capacitor _C1 , and no cutoff signal is output. Therefore, even when it is necessary to shut off the gas cutoff valve 1, the open state is maintained, which is dangerous.

Furthermore, in the configuration shown in FIG. 3, even if a return control signal is output by operating a switch or the like while the timer circuit 14 is operating, the operation is not stored, so the timer operation ends and the return pulse output circuit 15 can be input. After the condition is reached, the user must operate again to generate the return control signal, which is inconvenient.

[Means for solving problems]

The present invention was developed in view of the conventional problems as described above, and its means include a cutoff capacitor that is charged when the gas cutoff valve is cut off, and a charging voltage of the cutoff capacitor that is detected and set to a predetermined voltage. a charging detection circuit that outputs a detection signal when the gas cutoff valve is started; a return signal output circuit that outputs a return signal that causes the gas cutoff valve to return; and a return signal output circuit that generates an output signal upon input of a return control signal and stores this state. a memory circuit that clears the memory state by a cutoff control signal and prevents generation of the output signal due to input of the recovery control signal, and outputs the recovery signal based on the output signal of the memory circuit and the detection signal of the charge detection circuit. The circuit outputs a return signal.

[Effect]

In the above means, the cutoff capacitor is charged while the gas cutoff valve is cut off. When this charging voltage rises to a predetermined value, a detection signal is output from the charging detection circuit. On the other hand, if a return control signal is input during any period including during charging of the cut-off capacitor, it is stored in the memory circuit. Based on the detection signal and the output signal of the memory circuit, a return signal for returning the gas cutoff valve is output from the return signal output circuit. The memory circuit is cleared by the generation of the cutoff control signal, the generation of the output signal is blocked, and the recovery signal is no longer output from the recovery signal output circuit.

〔Example〕 Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a voltage is applied to the cutoff capacitor _C1 through a resistor _R1 when the cutoff valve 1 is cut off. The voltage of the capacitor _C1 is determined by the charging detection circuit 3.
is input. In the detection circuit 3, the voltage of the capacitor _C1 is applied to the base of the transistor _Q1 through the diode _D1 and the resistor _R2 . In addition, there are resistors R _{3 and 3} between the base and ground, and between the base and emitter, respectively.
R ₄ is connected. Its collector is connected to the base of transistor Q ₂ through resistors R ₅ and R ₆ , and the collector of transistor Q ₂ is connected to the connection point of series resistors R ₇ and R ₈ and output through resistor R ₉ .

The return control signal (open switch signal) is a NOR circuit
It is inputted to the set input S of a well-known RS flip-flop (hereinafter referred to as RSFF) 4 composed of IC ₂ and IC ₃ , and the output of the OR circuit IC ₄ is supplied to the reset input R. Further, the output Q becomes an input to the NAND circuit IC ₁ together with the output of the charge detection circuit 3. NAND
The output of the circuit IC ₁ is input to a low active return signal output circuit 5, which controls the cutoff valve drive circuit 2 and drives the cutoff valve 1.

A cutoff control signal (alarm signal) output in an emergency such as when a gas leak occurs is supplied as an input to the OR circuit IC ₄ and as a reset signal to the recovery signal output circuit 5. Further, a signal corresponding to the input signal of the return signal output circuit 5 is supplied to the other input of the OR circuit IC ₄ .
The output Q of the RSFF4 is inputted together with one input of the NAND circuit _IC1 to a display circuit 6 that lights up in an emergency. In addition, the power supply voltage V _DD supplied to the emitter of transistor Q ₁ is backed up and
The power supply voltage V _CC supplied to one end of _R7 is not backed up.

In such a configuration, if the charging voltage of the cutoff capacitor C ₁ is V _C , the base-emitter voltage at which transistor Q ₁ turns on is V _BE , and the forward voltage of diode D ₁ is V _D , then V _C = (1+R When the capacitor _C1 is charged to a voltage equal to _or higher than the charging voltage VC, which is ₂ / _R3 )・( _VDD − _VBE )+ _VD , the transistor _Q1 is turned off. The current that had been flowing to the base of transistor Q ₂ through resistor R ₅ is then cut off and transistor Q ₂ is also turned off. Here, if V _CC >V _DD , one input of the NAND circuit IC ₁ is supplied with an H-level voltage expressed by R ₈ /(R ₇ +R ₈ )·V _CC (≈V _DD ).

If the return control signal is input by operating the open switch and the output Q of RSFF4 becomes H level before one input of the NAND circuit IC ₁ becomes H level, the output of the charge detection circuit 3 becomes H level. The output of the NAND circuit IC ₁ becomes L level at the moment when the signal is reversed. As a result, a return signal is output from the return signal output circuit 5 to the drive circuit 2, and the cutoff valve 1
returns (opens).

At the same time as the return signal is output from the return signal output circuit 5, a reset signal is outputted to the reset input of RSFF4 through OR circuit _IC4 , and RSFF4 is reset and enters a state of waiting for a return control signal. Furthermore, when a shutoff control signal is input to the OR circuit IC ₄ to shut off the shutoff valve 1 due to a gas leak, a close switch signal, etc., a reset signal is output to the RSFF 4 and the return signal output circuit 5, and both are reset. Ru.
Therefore, even if the cutoff capacitor _C1 has completed charging (even if the output of the charge detection circuit 3 is at H level), no return signal is output. Therefore, no return signal is output from the return signal output circuit 5, and the cut-off state is maintained.

Note that, as mentioned above, the power supply voltage V _DD is backed up, but the power supply voltage V _CC is not backed up. Therefore, even if the cut-off capacitor _C1 has completed charging,
At the time of a power outage, the input voltage level of the NAND circuit IC ₁ , R ₈ /(R ₇ +R ₈ )·V _CC , becomes an L level, and no signal is output to the charge detection circuit 3. This ensures safety by preventing the shutoff valve 1 from returning during a power outage.

Further, a return control signal is input by operating the open switch, RSFF4 is set, and the output Q becomes H level. This output Q is input to the display circuit 6,
For example, when the open lamp provided in the display circuit 6 blinks, it indicates that the open switch has been operated.
As mentioned above, once the single-stage recovery control signal is input, the RSFF4 maintains the set state until the recovery signal is output from the recovery signal output circuit 5, and if the cut-off capacitor _C1 has not completed charging. But I remember this situation. Therefore, the capacitor
There is no need to operate the open switch again after _C1 completes charging and re-input the return control signal. Furthermore, when the cutoff control signal is input, RSFF4 is cleared, the output Q becomes L level, and the output of the return signal is blocked. As a result, the output of the NAND circuit IC ₁ is inverted to H level, and even if the charge detection circuit 3 outputs an H level signal, the return signal output circuit 5
Since the return signal is no longer output, the gas cutoff valve 1 enters the cutoff state.

[Effect of idea]

As described above, according to the present invention, the shutoff valve cannot be reset until after the shutoff capacitor has been charged to a predetermined potential, even if the return control signal is inputted before that. Therefore, even if the cut-off capacitor becomes insufficiently charged due to disconnection or the like, failure of the shut-off valve to close can be prevented, improving safety.

Furthermore, if a return control signal is input during the charging period of the cutoff capacitor, this signal is stored, so that the cutoff valve returns after charging is completed, and there is no need to input the return control signal again. This improves convenience during the return operation.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of a gas cutoff valve control device according to the present invention, and FIGS. 2 and 3 show conventional gas cutoff valve control devices. 1... Gas cutoff valve, 2... Drive circuit, 3... Charge detection circuit, 4... RS flip-flop, 5...
...Return signal output circuit, 6...Display circuit, C ₁ ...
Cutoff capacitor, 7... Cutoff capacitor charging circuit, 8... Switch circuit, 9... Recovery capacitor charging circuit, 10... Charge detection circuit, 11... Recovery pulse switch circuit, 12... Cutoff signal output circuit, 13 ... Cutoff pulse output circuit, 14 ... Timer circuit, 15 ... Return pulse output circuit.

Claims (1)

[Scope of utility model registration request] A cutoff capacitor that is charged when the gas cutoff valve is cut off, a charging detection circuit that detects the charging voltage of the cutoff capacitor and outputs a detection signal when the voltage rises to a predetermined voltage, and a charging detection circuit that causes the gas cutoff valve to return to its original state. a return signal output circuit that outputs a return signal; and a return signal output circuit that generates an output signal by inputting a return control signal, stores this state, clears the stored state by a cutoff control signal, and outputs the output signal by inputting the return control signal. 1. A gas cutoff valve control device, comprising: a memory circuit for preventing the occurrence of a charge detection circuit; and a return signal is output from the return signal output circuit based on an output signal of the memory circuit and a detection signal of a charge detection circuit.