JPH0615357Y2 - Gas leak alarm device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a gas leak alarm device for issuing an alarm after a predetermined time has passed after detecting a gas leak.

[Conventional technology]

As shown in FIG. 3, a conventional gas leak alarm device generally includes a gas detection circuit 1 having a gas detection element, a delay circuit 2 for performing a delay operation, an alarm circuit 3, an alarm buzzer 4, a drive power source 5, etc. When the circuit 1 detects a gas leak and gives a gas leak signal to the delay circuit 2, and the gas leak signal is input to the delay circuit 2 in order to prevent malfunction of this device, the gas leak is delayed for a predetermined time from this and the gas leak is confirmed. After confirming that there is such a signal, a signal is sent to the alarm circuit 3, and the alarm circuit 3 sounds the buzzer 4 or lights the indicator lamp. The driving power source 5 is supplied with power from a commercial power source and applies an appropriate DC voltage to the alarm device.

[Problems to be Solved by the Invention] In such a gas leak alarm device, after the power is turned on, the gas detection element of the gas detection circuit 1 is heated and stabilized.
The initial stabilization time of about 0.5 to 3 minutes is required, and the alarm circuit 3 may cause the buzzer to ring during this period. Further, when the gas leak alarm device is newly installed and also when regularly inspected, an inspection gas prepared separately for this purpose is sprayed on the gas detection element to check whether the alarm circuit 3 gives an alarm. In this case, there is a drawback in that the inspection gas must be blown for longer than the delay time of the delay circuit 2. In particular, since city gas is lighter than air, the gas leak alarm device is generally installed at a high place such as a ceiling.
There is a drawback in that it is difficult to perform this inspection gas spraying work for a long time.

Therefore, an object of the present invention is to provide a gas leak alarm device capable of shortening the inspection time of the gas detection circuit.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a gas detection circuit that detects gas and sends out a gas leakage signal, and starts when the gas leakage signal from the gas detection circuit starts and the gas leakage signal continues for a predetermined time. In a gas leak alarm device equipped with a delay circuit for transmitting a delay signal and an alarm circuit for issuing an alarm based on the delay signal of the delay circuit, the alarm circuit can be activated by transmitting an operation signal after a predetermined time has elapsed since the power was turned on. And an operation signal sent from the initial stabilization circuit, a check signal is sent for a predetermined time, and the gas leak signal of the gas detection circuit is issued as a warning during the period when the check signal is sent. And a check circuit that is applied directly to the circuit.

[Action]

Immediately after the power is turned on, the gas detection circuit is unstable, so the operation of the device is suppressed. Then, when the initial stabilization circuit sends an operation signal, the inspection circuit sends an inspection signal, and after a predetermined time, this inspection signal The alarm circuit is operated directly by the signal of the gas detection circuit without passing through the delay circuit until disappears, and when the inspection signal disappears, it goes through the delay circuit. When sprayed,
If an alarm is issued immediately, it can be recognized that the gas detection circuit is normal, and if the inspection signal is extinguished and the inspection gas is blown and then the delay circuit delays the alarm, the delay circuit is normal. Can be recognized.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals as those in FIG. 3 and their detailed description is omitted. In FIG. 1, the gas leak alarm device is equipped with a gas detection circuit 1, a delay circuit 2, an alarm circuit 3 and a buzzer 4 similar to the conventional one, but this gas leak alarm device also has an initial stabilization circuit 6, Check circuit 7, OR circuit 8, 2 ANs
D circuits 9 and 10 are provided. Of these, the initial stabilization circuit 6
The check circuit 7 and the OR circuit 8 and the AND circuits 9 and 10 are combined to perform the following operations. That is, the initial stabilization circuit 6 is a circuit that suppresses the operation of the alarm circuit 3 from the time the power is turned on until the gas detection circuit 1 stabilizes.
It has a plurality of output terminals and outputs an operation signal after a predetermined time has passed since the power was turned on. The inspection circuit 7 is composed of a timer circuit that directly activates the alarm circuit 3 without delaying the output of the gas detection circuit 1 by the delay circuit 2 when the power is turned on or when the inspection is performed. Therefore, the check circuit 7 sends the check signal for a predetermined time at the same time when the initial stabilizing circuit 6 sends the operation signal.

Explaining the connection of each circuit below, the output end of the gas detection circuit 1 is connected to one input end of the delay circuit 2 and the AND circuit 9, and the output end of the delay circuit 2 is connected to one input end of the OR circuit 8. Has been done. Further, one output end of the initial stabilization circuit 6 is connected to the check circuit 7, and the other output end thereof is the AND circuit 10.
Is connected to one input end. The output terminal of the check circuit 7 is connected to the other input terminal of the OR circuit 8, the output terminal of the OR circuit 8 is connected to the other input terminal of the AND circuit 9, and AN
The output terminal of the D circuit 9 is connected to the other input terminal of the AND circuit 10. The output end of the AND circuit 10 is connected to the alarm circuit 3, and the output end of the alarm circuit 3 is connected to the buzzer 4. Of course, an indicator lamp may be connected instead of the buzzer, or both the buzzer and the indicator lamp may be connected.

The operation of the gas leak alarm device will be described below with reference to the time chart shown in FIG. FIG. 2 shows the power supply P, the operation signal S ₁ of the initial stabilization circuit 6, and the inspection signal S of the inspection circuit 7.
₂ , the gas leak signal S ₃ of the gas detection circuit 1, the delay signal S ₄ of the delay circuit 2, and the alarm signal S ₅ of the alarm circuit 1 are listed in this order. When the power is turned on at time t ₁ , the initial stabilization circuit 6 is started, and the operation signal S ₁ is transmitted at time t ₂ after the predetermined time T ₁ . Since the output of the AND circuit 10 is 0 until the operation signal S ₁ is sent, the alarm circuit 3 does not operate. That is, the output of the alarm circuit 3 is suppressed for the time T ₁ until the gas detection circuit 1 stabilizes, and the buzzer 4 does not ring. At the same time as the operation signal S ₁ is sent, the check circuit 7 sends the check signal S ₂ . When the check signal S ₂ is sent, the output signal of the OR circuit 8 is sent, and this signal is applied to the other input terminal of the AND circuit 9. Therefore, the inspection gas is sprayed on the gas detection element at time t.
_If the signal S _3-a is input to one of the input terminals of the AND circuit 9 as shown in FIG. ₃ , the AND circuit 9 immediately sends the signal and the AND circuit 10 sends the output signal, without passing through the delay circuit 2. Then, the alarm circuit 3 is activated, and the alarm signal S ₅ is sent to make the buzzer 4 ring. However, the inspection signal S ₂ disappears at time t ₄ when the predetermined time T ₂ has passed. Therefore, if the delay signal S ₄ of the delay circuit 2 is 0, the output signal of the OR circuit 8 is 0. Therefore, even if the gas leak signal S ₃ is input, the output signal of the AND circuit 9 is 0 and the output signal of the AND circuit 10 is 0. Is also 0, and the alarm circuit 3 does not send an alarm signal. This is the normal state. Here, the gas detection circuit 1 detects gas,
If the gas leak signal S _3-b is sent at time t ₅ , the predetermined time T
_The delay signal S ₄ is transmitted from the delay circuit 2 at the time t ₆ after ₃ delays, and thus the signal is transmitted from the OR circuit 8 and the AND circuit 10 transmits the signal by the signal of the AND circuit 9, and the alarm circuit 3
Is activated, the alarm signal S _5-b is sent to make the buzzer 4 ring.

This gas leak alarm device has a delay circuit 2 when the gas detection circuit detects gas while the inspection circuit 7 is sending out an inspection signal.
Since the alarm circuit 3 is immediately activated without passing through the above, if the alarm is immediately issued when this device is newly installed and the power is turned on, it can be checked in a short time that the gas detection circuit 1 is normal, and If the inspection gas is sprayed after the inspection signal S ₂ of the circuit 7 is extinguished and an alarm is issued after the delay time by the delay circuit 2 has passed from this spraying, it can be checked that the delay circuit 2 is normal, and the gas detection circuit 1 and the delay Both of the circuits 2 can be checked.

[Effect of device]

According to the present invention, after the power is turned on, an operation signal is sent from the initial stabilization circuit to stabilize the circuit state, and at the same time, an inspection signal is sent from the inspection circuit, which prevents malfunctions when the gas detection circuit detects gas during inspection of the device. If a signal is immediately applied to the alarm circuit without a delay circuit and an alarm is issued, it can be checked in a short time that the gas detection circuit is normal, and the inspection signal from the inspection circuit disappeared. After that, since the delay circuit is utilized, if the inspection gas is sprayed after the inspection signal disappears, if the alarm is issued after the delay circuit by the delay circuit elapses from the spraying, it is possible to check that the delay circuit is normal. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a gas leak alarm device according to the present invention, FIG. 2 is a time chart showing the operation of FIG. 1, and FIG. 3 is a block diagram showing an example of a conventional gas leak alarm device. Is. 1 ... Gas detection circuit, 2 ... Delay circuit, 3 ... Alarm circuit, 6 ... Initial stabilization circuit, 7 ... Inspection circuit.

Claims (1)

[Scope of utility model registration request] 1. A gas detection circuit for detecting a gas and sending a gas leak signal, and a delay for starting by a gas leak signal from the gas detection circuit and sending a delay signal when the gas leak signal continues for a predetermined time. In a gas leak alarm device including a circuit and an alarm circuit that issues an alarm based on the delay signal of the delay circuit, an initial stabilization circuit that sends an operation signal after a predetermined time from power-on to enable the alarm circuit. , An inspection circuit for transmitting an inspection signal for a predetermined time when an operation signal is transmitted from the initial stabilization circuit, and for directly applying the gas leak signal of the gas detection circuit to the alarm circuit during the period during which the inspection signal is transmitted. And a gas leak alarm device.