JPH037657Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a gas alarm shutoff device that not only gives an alarm in the event of a gas leak, but also shuts off the supply of gas using a gas shutoff valve. The present invention relates to a gas alarm shutoff device that is controlled by utilizing the difference in power consumption between an alarm when it is on standby and when it is in alarm.

[Conventional technology]

This type of conventional device is generally configured as shown in Figure 3, in which 1 is a gas alarm, and AC power supply
Power transformer T ₁ that supplies AC100V to the primary side
and a gas alarm main circuit A including a gas leak detection means (gas sensor) provided on the secondary side of the transformer _T1 .
, a buzzer B such as an electromagnetic buzzer, and a thyristor SCR ₁ connected in series to an AC power source, and the gate of the thyristor SCR ₁ is connected to the output of the main circuit A. A power consumption detector 2 supplies AC power to the gas alarm 1 and detects its power consumption. Reference numeral 3 denotes a gas cutoff valve that cuts off gas supply, and is driven by the detection output of the power consumption detector 2.

The power consumption detector 2 is constructed as shown in FIG. That is, the power transformer _T2 and the transformer
A power supply circuit 2 ₁ connected to the secondary side of T ₂ and supplying driving power to the detector 2 , and a pair of photovoltaic circuits connected between the primary side of the power transformer T ₂ and the AC power input of the gas alarm 1 Diodes D _P2 , D _P3 and resistors R ₄
, phototransistors Q _P2 and Q P3 that receive the light emitted from the photodiodes D _P2 and D _P3 , a timer circuit 2 ₂ driven by the output of the photo transistor Q _P2 or _{Q P3 ,} and a timer circuit 2 2 of the timer circuit 2 ₂ . A timer circuit 2 ₂ driven by the output, and the timer circuit 2 ₂
Gas cutoff valve drive circuit 2 driven by the output of ₃
It consists of The photodiodes D _P2 and D _P3 are connected in parallel with each other in opposite directions, and are further connected in parallel with a resistor _P4 . In addition, the gas cutoff valve drive circuit 2 ₃ includes:
A capacitor C ₂ is connected, and a drive signal for the gas cutoff valve 3 is output by discharging the capacitor C ₂ .

In such a configuration, the main circuit A of the gas alarm 1
However, in the standby state where no gas leak occurs, the thyristor is
The on-current to the gate of SCR ₁ is not output, and thyristor SCR ₁ maintains an off state. Therefore, no drive current flows through the buzzer B. In such a standby state, the buzzer B is not driven as described above, so the power consumption of the gas alarm 1 is mainly due to the operation of the gas alarm main circuit A. Since the power consumption by the main circuit A is small, the AC current i flowing through the resistor _R4 of the power consumption detector 2 connected in series with the AC power source of the gas alarm A is also small, and the voltage drop therebetween is small. Photodiode D _PS ,
Since D _P3 is not turned on and is in an off state, both phototransistors Q _PS and Q _P3 are also turned off. Therefore, the timer circuit 2 ₂ and the gas cutoff valve drive circuit 2 ₃ are not driven, and the gas cutoff valve 3 is not driven.

On the other hand, if a gas leak occurs, main circuit A
Detects gas leakage and outputs a detection signal to the gate of thyristor _SCR1 . As a result, the thyristor SCR ₁ is turned on, AC power is supplied to the buzzer B, the buzzer B is activated, and an alarm is generated. At the time of such an alarm, the power consumption of the gas alarm 1 is significantly increased compared to when it is on standby because the operating current of the main circuit A and the driving current of the buzzer B are added. Therefore, a large AC power supply i flows through the resistor _R4 of the power consumption detector 2 connected in series with the AC power supply of the gas alarm 1, resulting in a large voltage drop.

This voltage drop causes the photodiode to
D _P2 or D _P3 turns on and lights up. Phototransistor Q _P2 or Q _P3 receives this light emission and one turns on, so its on output is sent to timer circuit 2.
₂ is input. The timer circuit ₂₂ receives the ON output of the phototransistor _QP2 or _QP3 and outputs a drive signal to the gas cutoff valve drive circuit ₂₃ after a predetermined internally set delay time has elapsed. As a result, the capacitor _C2 connected to the drive circuit ₂₃ starts discharging, outputting a drive signal to the gas cutoff valve 3, and the gas cutoff valve 3 being driven and closed, causing gas to flow out. Cut off the supply.

[Problem to be solved by the invention] In such a conventional device, the buzzer B for generating an alarm of the gas alarm 1 connects the AC power of the power consumption detector 2 via the primary side of the power transformer _T1 . Directly connected and electrically connected to the power output terminal. Therefore, noise arriving at the AC power line may be input to the gas alarm generation circuit A via the buzzer B and the thyristor _SCR1 , causing the main circuit A to malfunction.

Also, if an electromagnetic buzzer is used as buzzer B,
The electromagnetic buzzer B generates large vibrations when driven, and a gas detector (gas sensor) built into the main circuit A is easily disconnected.

[Means for solving problems]

The present invention has been developed in view of the above points, and includes a gas alarm that detects gas leaks and issues an alarm in the event of a gas leak. A gas alarm equipped with a power consumption detector that detects the power consumption of the power consumption detector, and a gas cutoff valve that is driven by the detection output of the power consumption detector and cuts off the gas supply when the power consumption reaches the level required for a gas leak alarm. The gas alarm includes an alarm means that is activated when a gas leaks, a resistor electrically isolated from the alarm means and coupled to a power consumption detector, and controlled in accordance with the activation of the alarm means. and a switch inserted between the resistor and the power consumption detector.

[Effect]

In the above configuration, the alarm means is not driven when the gas alarm is in the standby state, and is driven when the gas alarm is in the alarm state. The opening and closing of the switch is controlled depending on whether the alarm means is alerted or not activated. Therefore, different currents flow through the resistor in both states. Therefore, the power consumption detector detects the power consumption of the resistor and distinguishes between standby mode and alarm mode. As a result, in the event of an alarm, a drive signal is output from the power consumption detector to the gas cutoff valve to shut off the gas cutoff valve. At this time, since the driving means and the resistor are electrically separated,
Noise arriving at the power line of the gas alarm is not input to the alarm means through the resistor, thereby preventing malfunctions.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings. 1st
In the figure, the same parts as in FIG. 3 are given the same reference numerals. A series circuit of a photodiode D _P1 and a resistor R ₂ is connected to the detection output in the main circuit A of the gas alarm 1. In addition, on the primary side (AC power supply side) of the electromagnetic transformer _T1 , there is a resistor _R1 and a photothyristor SCR _P1.
and capacitors in parallel configuration for noise protection.
C ₁ and resistor R ₃ are connected in series. The noise protection capacitor C ₁ and the resistor R ₃ are connected in parallel between the gate and cathode of the photothyristor SCR _P1 . Photodiode D _P1 and photothyristor
SCR _P1 constitutes switch SW ₁ using a thyristor photocoupler, and is optically coupled and electrically separated. Further, the buzzer B uses, for example, a piezoelectric buzzer with little vibration, and constitutes the alarm means ₁₁ together with the gas alarm main circuit A. Note that the configuration of the power consumption detector 2 is similar to that of the diode 2 shown in FIG. 2, and the primary side of the power transformer T ₁ and the resistor R ₁ of the gas alarm 1 are connected to the AC power output.

In such a configuration, when the gas alarm 1 is in a standby state, no gas leakage detection output is generated from the main circuit A, so the photodiode D _P1 is turned off and is in an extinguished state. Also, piezoelectric buzzer B is not driven. Therefore, the photothyristor SCR _P1 is off, and no current flows through the resistor _R1 .

On the other hand, in the event of an alarm, a detection output is generated from the main circuit A, which drives the piezoelectric buzzer B, and also turns on the photodiode D _P1 to cause it to emit light. Therefore, the photothyristor SCR _P1 is turned on, and current flows through the resistor _R1 from the AC power source.

Gas alarm 1 during standby and alarm
Comparing the power consumption of the gas alarm ₁ , there is no power consumption in the resistor R1 during standby, and the power consumption due to the operation of the main circuit A is approximately the power consumption of the gas alarm 1, and the consumption is small. On the other hand, at the time of alarm, the power consumption due to the operation of the main circuit A and the power consumption due to the current flowing through the resistor _R1 are added, and the power consumption of the gas alarm 1 is significantly increased compared to when it is on standby. Therefore, the power consumption detector 2 detects the AC power supply i of the AC power supply line due to this power consumption with the resistor _R4 , and when the voltage drop of the resistor _R4 becomes large in the event of an alarm, the photodiode D _P1 or D _P2 is turned on. becomes.
Phototransistor Q _P2 or Q _P3 as described above.
is turned on, the timer circuit 2 ₂ and the gas cutoff valve drive circuit 2 ₃ are driven, and the gas cutoff valve 3 is driven to cut off the gas supply.

At this time, the resistor _R1 and the main circuit A are electrically separated by the thyristor photocoupler, and the buzzer B
is also separated from the resistor _R1 . Therefore, noise arriving at the AC power supply line will not be input to the main circuit A through the resistor _R1 . Further, the power supply side of the main circuit A is also separated by the primary side and secondary side of the power transformer _T1 , so that noise on the power line is blocked.

[Effect of idea]

As described above, according to the present invention, it is possible to prevent the gas alarm from malfunctioning due to noise coming into the power supply line. Furthermore, if a piezoelectric buzzer is used as a means for generating an alarm, it is possible to prevent disconnection of a gas sensor or the like due to vibration.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the device according to the present invention, Fig. 2 is a block diagram showing the configuration of the power consumption detector in the present invention and the conventional device, and Fig. 3 is a block diagram showing the conventional device. It is. 1...Gas alarm, 2...Power consumption detector, 3
... Gas cutoff valve, 1 ₁ ... Alarm means, A ... Gas alarm main circuit, B ... Piezoelectric buzzer, 2 ₁ ... Power supply circuit, 2 ₂ ... Timer circuit, 2 ₃ ... Gas cutoff valve drive Circuit, _R1 ...Resistor, D _P1 ...Photodiode, SCR _P1 ...Photothyristor.

Claims (1)

[Scope of Claim for Utility Model Registration] A gas alarm that detects gas leaks and issues an alarm in the event of a gas leak, and that supplies power to the gas alarm and detects the power consumption of the gas alarm during standby and alarm times. A gas alarm cutoff device comprising a power consumption detector and a gas cutoff valve that is driven by the detection output of the power consumption detector and cuts off the supply of gas when the power consumption reaches the level required for a gas leak alarm, the gas alarm cutoff device comprising: The gas alarm includes an alarm means that is activated when a gas leaks, a resistor that is electrically separated from the alarm means and coupled to the power consumption detector, and a resistor that is controlled in accordance with the activation of the alarm means and that is connected to the power consumption detector. and a switch inserted between the power detectors, and the power consumption detector detects the power consumption of the gas alarm during standby and alarm times by the current flowing through the resistor in response to opening and closing of the switch. A gas alarm cutoff device characterized by: