JPH0465435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas cylinder valve controller that automatically operates a gas valve valve when a gas leak occurs.

Devices that automatically shut off the gas vent when a gas leak occurs typically include a gas leak sensor, a gas vent valve having a solenoid, and a gas vent valve controller. In this gas cutoff device, when the gas leak sensor detects a gas leak,
A gas shutoff valve controller drives a solenoid to cut off the gas supply. In such a gas shutoff device, the gas shutoff valve controller basically operates to determine sensor output and drive a solenoid in the event of a gas leak.

A conventional gas shutoff valve controller is driven by a separate power supply device that includes a circuit for determining the sensor output and a circuit for driving the solenoid.

However, if you install a separate power supply like this,
This led to an increase in size and cost, and the disadvantage was that the power supply device had to be constantly operating even if there was no gas leak, resulting in unnecessary power consumption. Another drawback was that the controller could only be installed in a location where a power source could be accessed, and it would not work in the event of a power outage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas vent controller that does not require a power supply and operates reliably even when the input current from a sensor is a minute current.

In this invention, it is not necessary to drive the solenoid very often, and it is sufficient to apply one drive pulse to drive the solenoid, and the power consumption of the sensor output discrimination circuit, etc. is reduced. This was done with the focus on its relatively small size.

In summary, the present invention is configured such that when a gas leak detection sensor outputs a signal at a normal level, a level detection circuit, etc. operates using the signal at that level as a power source, and the level is used to pump up and charge the signal. The present invention is characterized in that the voltage is increased to a constant voltage by the voltage, and the charged electric charge is discharged to the solenoid when a gas leak is detected.

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

FIG. 1 is a block diagram of a gas cylinder valve controller according to an embodiment of the present invention.

In the figure, a gas leak detection sensor 1 detects the gas concentration around its installation location, and outputs a signal at a normal level when the gas concentration is below a permissible value.
Outputs a gas leak level signal when it exceeds the allowable value. Additionally, in the event of a trouble such as a failure of the sensor drive power supply, a trouble level signal is output. The normal level, gas leak level, and trouble level are set in advance, and the signals for these levels are usually DC voltages of 6V, 12V, and 0V.

The sensor output is placed on lines a and b and given to the gas cylinder and valve controller. This controller includes a level detection circuit 2 for 6V and 12V among the above three levels, an oscillation circuit 3, and a booster circuit 4.
, a pulse generation circuit 5, and a solenoid drive circuit 6
It is composed of.

Level detection circuit 2 detects the signal level of the sensor output carried on lines a and b, and outputs a 6V detection signal to terminal c when the level is 6V (normal state), and outputs a 6V detection signal to terminal c when the level is 12V (gas leakage). state), a 12V detection signal is output to terminal d.

The oscillation circuit 3 is driven when receiving the 6V detection signal and provides an oscillation pulse to the booster circuit 4. Further, the pulse generating circuit 5 is driven when receiving the 12V detection signal, and after a certain delay time has elapsed, provides one pulse, which is a solenoid drive circuit activation pulse, to the solenoid drive circuit 6.

The booster circuit 4 consists of a series circuit of a capacitor C ₁ connected in parallel to lines a and b, an inductor L forming a discharge path for this capacitor C ₁ , a switching transistor Tr ₁ , and a rebound voltage v _L of the inductor L. A large capacitor _C2 that charges the
A Zener diode ZD ₁ is provided between the capacitor C ₂ and the inductor L to prevent backflow and protect the capacitor, and a Zener diode ZD ₂ forms part of the charging path for the capacitor C ₂ . The capacitor _C2 is charged to a predetermined voltage by the pump-up operation. The operation of this booster circuit 4 will be explained next.

First, when the sensor output is 6V (normal level), transistor _Tr1 switches according to the oscillation pulse. During the off-period t ₁ of the transistor Tr ₁ (see FIG. 2), the capacitor C ₁ is charged with an input voltage of 6V. When timing A arrives,
Transistor Tr ₁ is turned on. Therefore, the capacitor C ₁ starts discharging through the series circuit of the inductor L and the transistor Tr ₁ as a discharging path, and this discharging continues during the on period t ₂ . At timing B, the transistor _Tr1 is cut off to stop the above-mentioned discharge. At this time, a rebound voltage vL of -Ldi/ _dt is generated as a high voltage across the inductor L, and the capacitor _C2 is charged by this voltage _vL . The capacitor _C1 is provided to improve efficiency by storing energy using the time when the transistor _Tr1 is off and transferring energy to the inductor when the transistor is on. However, if you don't mind the lower efficiency, you can omit this capacitor _C1 . If the capacitor _C1 is omitted, energy will be stored in the inductor L by the current flowing from the power source during time _t2 in FIG. The above operation is 1
As the cycle progresses, the charging voltage v _c of capacitor C ₂ is increased. The Zener diode _ZD1 prevents overcharging of the capacitor _C2 , clips the charging voltage to the Zener voltage, and further prevents reverse current.

In this way, this booster circuit 4 charges the capacitor _C2 with a constant voltage by the action of the capacitor ₁ and the inductor L when the voltage is at a normal level.

Next, when the sensor output is 12V (gas leakage level), the oscillation circuit 3 is not driven, so the transistor _Tr1 is turned off, and the pulse generation circuit 5 is activated instead. As mentioned above, the pulse generation circuit 5
One pulse is generated after a certain delay time has elapsed since the 12V detection signal is received, so during this delay time (several seconds to several tens of seconds), capacitor C ₂
discharge has been stopped. During this delay time, since there is no switching operation, the inductor L has a low impedance. Therefore, with a voltage clipped to the Zener voltage of Zener diode ZD ₂ , capacitor C ₂ from lines a, b
Charging current flows directly to the Thus the capacitor
When C ₂ is sufficiently charged, the drive circuit 6 is activated and discharge occurs in a short period of time. Note that the Zener diode _ZD2 serves both the role of clipping the gas leakage level to a constant voltage as described above, and the role of configuring a path for the charging current _i1 during pump-up operation. If this clip voltage is set higher than the clip voltage caused by the Zener diode _ZD1 , the charging voltage can be increased accordingly during the delay time.

As is clear from the above description, this booster circuit 4 is configured to directly utilize the sensor output to charge a large capacity capacitor _C2 with a predetermined voltage. That is, this booster circuit 4
This circuit integrates the minute current of , and stores the amount of charge necessary to form a constant current pulse.

The solenoid drive circuit 6 includes a transistor Tr ₂ and a transistor Tr ₃ . Transistor Tr ₂ is
Acts as a switch to discharge the charge in the capacitor C ₂ to the solenoid 7, and the transistor Tr ₃
acts as a drive control transistor that controls on/off of the transistor _Tr2 . transistor
Tr ₃ is driven by a pulse given from the pulse generation circuit 5, and the transistor is turned on while the pulse is being output.
Turn on Tr ₂ . As a result, the charge stored in the capacitor C ₂ is discharged to the solenoid 7 during the time when the pulse generation circuit 5 is receiving the pulse. Since the capacitor _C2 has a large capacity, the discharge current at this time is large enough to drive the solenoid 7, and can reliably operate the plunger (not shown) connected to the solenoid. .

Note that although the level detection circuit 2, oscillation circuit 3, and pulse generation circuit 5 each include active elements such as transistors, the power consumption of these circuits is not so large. Each circuit can therefore be driven directly by the sensor output. On the other hand, since the solenoid drive circuit 6 is a circuit that discharges the charging potential of the capacitor _C2 , voltage supply from lines a and b is not necessary. This is because the driving current of the circuit is given by the charge in the capacitor _C2 .

In this embodiment, the drive circuit 6 is further provided with a base current supply path 8 including a switch 80, and by turning on the switch 80, the transistor
The base current of Tr ₃ is also obtained from the charge of capacitor C ₂ . This advantage is significant when checking the operation, or when lines a and b are disconnected or the sensor 1 is broken and the pulse generating circuit 5 stops operating even though gas leakage has occurred. . In such a case, if the switch 80 is turned on, the charge in the capacitor C ₂ will be discharged to the solenoid 7.

As described above, this controller does not require a power supply circuit, and the pump-up operation of the booster circuit 4 can sufficiently charge the amount of charge required to drive the solenoid 7 during normal operation. Therefore, there is no need to take into account the reliability of the power supply, and the controller is extremely reliable and can operate reliably in the event of a gas leak.

Next, FIG. 3 shows an actual circuit of the above controller.

In the figure, transistors Tr ₄ and Tr ₅ are level detection transistors of the level detection circuit 2, with transistor Tr ₄ detecting 12V and transistor Tr ₅ detecting 6V. When 12V is detected, transistor Tr ₄ turns on, transistor Tr ₅ turns off,
When 6V is detected, transistor Tr ₄ is turned off and transistor Tr ₅ is turned on. When detecting 6V, which turns on the transistor Tr ₅ , the gate G ₁ is opened via the diode D ₁ , so the oscillation output of the oscillation circuit 3 is sent to the transistor Tr ₁ of the booster circuit 4 . Therefore, capacitor _C2 is charged during normal operation when 6V is detected. on the other hand. Transistor Tr ₄ turns on
When 12V is detected, gate _G1 is closed and capacitor _C3 is charged. And when the charging potential of capacitor _C3 becomes constant, the n-gate thyristor
PUT is activated and sends a pulse to transistor Tr ₃ through diode D ₂ . This time constant is the resistance r ₃
and capacitor _C3 , whose value is determined by
The time from when 12V is detected to when the thyristor PUT is activated is determined to be approximately 10 to several tens of seconds. When the transistor Tr ₃ is turned on in this way, the charge in the capacitor C ₂ is discharged to the solenoid 7 via the transistor Tr ₂ . Note that when the transistor Tr ₃ is turned on, the gate G ₂ is opened by a path connecting the diode D ₃ and the inverter INV. Therefore, the buzzer BZ is activated and an alarm is issued to the outside.

When a gas leak occurs, that is, when 12V is detected, the solenoid 7 is driven as described above, but this controller includes a switch 80 in the solenoid drive circuit 6.
Since this switch is provided, the solenoid 7 can also be driven by operating this switch. switch 80
When in the on state, part of the charge in the capacitor _C2 flows to the base of the transistor _Tr3 , so even if the thyristor PUT does not operate, the solenoid can be driven by operating this switch.

This controller also uses transistor Tr ₂
Equipped with a guarantee circuit to prevent short circuits on the output side. Output side short circuits may occur particularly when repairing a disconnection on the output side. Therefore, this guarantee circuit discharges the charge stored in capacitor _C2 to a path other than the output circuit when the output side is disconnected. This guarantee circuit consists of diodes D ₄ , D ₅ ,
and including resistor r ₄ . When the output side of transistor Tr ₂ is not disconnected, the collector of transistor Tr ₂ is at a "low" level. transistor
When the output side of Tr ₂ is disconnected, the collector of transistor Tr ₂ goes to a "high" level (approximately 6V) through the path of resistor r ₄ and diode D ₄ . Therefore, the transistor Tr ₃ is turned on through the path of the resistor r ₄ and the diode D ₅ , and the charge stored in the capacitor C ₂ becomes the collector current of the transistor Tr ₃ and is consumed.

Note that the light emitting diode L is a lamp for confirming operation that emits light when the solenoid 7 is operated, and emits light in response to an operation signal from a reed switch (not shown) provided in the solenoid 7.

As described in detail above, according to the present invention, since a power supply device is not required, the overall shape is reduced.
Moreover, low power consumption and low cost can be achieved. Furthermore, since there is no power supply device, the overall reliability is improved, and the solenoid can be reliably driven even during a power outage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a gas cylinder valve controller according to an embodiment of the present invention, FIG. 2 is an oscillation pulse waveform diagram of an oscillation circuit, and FIG. 3 is a detailed circuit diagram of the controller. 1... Gas leak detection sensor, 2... Level detection circuit, 3... Oscillation circuit, 4... Boost circuit, 5...
Pulse generation circuit, 6... Solenoid drive circuit, 7
……solenoid.

Claims (1)

[Claims] 1. Using a sensor that outputs three-level signals of normal level, trouble level, and gas leak level in response to each state of normality, trouble, and gas leakage,
The output of the sensor is supplied as a power source and input to a gas inlet valve controller that drives a solenoid for operating a gas inlet valve when the output level of this sensor is at the gas leakage level. , the normal level and gas leakage level detection circuit comprising a normal level detection terminal and a gas leakage level detection terminal; the output of the sensor is supplied as a power supply, the output signal of the normal level detection terminal is input, and the output signal is an oscillation circuit that oscillates when the sensor is input; the output of the sensor is supplied as a power supply; the output signal of the gas leak level detection terminal is input;
a pulse generating circuit that generates a solenoid drive circuit operating pulse when the output signal is input; a switching transistor; an inductor connected in series with the switching transistor; and a capacitor charged with the rebound voltage of the inductor when the switching transistor is turned off, the output of the sensor is supplied to a power supply terminal, and the input terminal of the switching transistor is connected to the oscillation output terminal of the oscillation circuit. a booster circuit connected in series to a capacitor voltage output terminal of the booster circuit and connected to the pulse generation circuit, which turns on when a pulse for operating the solenoid drive circuit is input from the pulse generation circuit; A solenoid drive circuit that outputs a charging voltage of a capacitor to the gas cylinder valve shutoff solenoid, and a gas cylinder valve shutoff controller comprising the following.