JPH0534078Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas leak alarm device that drives a gas cutoff valve in the event of a gas leak, and more particularly to a gas leak alarm device that prevents self-damage due to gas.

[Conventional technology]

A conventional gas leak alarm device is constructed as shown in FIG. In the figure, 1 is a gas alarm that detects a gas leak, 2 is a gas circuit breaker that drives a gas cutoff valve 3 based on the output of the gas alarm 1, and 4 is a power plug that supplies AC power to the gas alarm 1. It is.

The gas alarm 1 includes a gas alarm main circuit 8 that detects gas leaks, a detection circuit 17, and an external output circuit 9 that receives the outputs of the main circuit 8 and the detection circuit 17 and outputs a drive signal to the gas circuit breaker 2. and a backup power supply 10.

Further, a limit switch 18 is built into the power plug 4, and is activated when the power plug 4 is pulled out from the power outlet. Switching of the limit switch 18 is detected by the detection circuit 17. Also, for AC power, plug 4
It is supplied to the main circuit 8 via.

In such a configuration, when the power plug 4 is attached to an outlet and AC power is normally supplied to the gas alarm 1, the limit switch 18 in the plug 4 does not operate, and the detection circuit 17 outputs a detection output. does not occur. In this state, the main circuit 7 constantly monitors the gas leakage state, and if a gas leak occurs, the main circuit 8 outputs a detection signal, drives the gas circuit breaker 2 through the external output circuit 9, and operates the gas cutoff valve. Block 3.

On the other hand, when the power plug 4 is disconnected from the outlet due to self-damage, the limit switch 18 is activated and turns on or off, this state is detected by the detection circuit 17, and the detection output is passed through the external output circuit 9 to the gas circuit breaker. Supply to 2. As a result, even when the power plug 4 is pulled out from the outlet, the gas circuit breaker 2 is driven and the gas shutoff valve 3 is shut off.

The backup power supply 10 is provided to compensate for the operation of the detection circuit 17, the external output circuit 9, and the main circuit 8 when the plug is pulled out when power is no longer supplied to the gas alarm 1 during a power outage. .

[Problem that the invention attempts to solve]

In the conventional device configured as described above,
If an extension cord such as a table tap is connected between the AC power source and the power plug 4, there is no limit switch installed at the connection between the extension cord and the AC power source to detect if the extension cord is pulled out. Such a condition cannot be detected when the AC power source and extension cord are unplugged.

Further, due to restrictions on the structure of the power outlet, the operation of the limit switch 18 may become uncertain depending on the shape of the outlet, and if the power plug 4 is not inserted into the outlet sufficiently, the limit switch 18 will be activated and the detection circuit 17 detects this and causes a malfunction.

[Means for solving problems]

The present invention has been developed in view of the conventional problems as described above, and as shown in FIG. A gas alarm 1 which is activated by inserting a power plug 4 into a power outlet 11 from which gas is led out and detects gas leakage, and a gas circuit breaker 2 which drives a gas cutoff valve 3 by the output of the gas alarm 1. The gas leak alarm device 1 includes an oscillation circuit 5, a level detection circuit 6 for detecting the output level of the oscillation circuit, and
The oscillation circuit 5 includes an energization detection circuit 7 that detects that the gas alarm 1 is supplied with power from the AC power supply 16 and controls the output of the detection output of the level detection circuit 6 based on the detection output. The output is led out to the power plug 4, and the level detection circuit 6 detects the output level of the oscillation circuit 5 during a power outage and when the power plug 4 is pulled out from the power outlet 11, and the output level is output from the power outlet 11 of the power plug 4. Level detection circuit 6 only when pulling out
The detection output of the energization detection circuit 7 drives the gas circuit breaker 2, and when the gas alarm 1 is supplied with power from the AC power source 16, the detection output of the energization detection circuit 7 drives the level detection circuit. This configuration is configured to cut off the detection output to the gas circuit breaker 1 of No. 6.

[Effect]

In the above means, when the power plug 4 is attached to the power outlet 11 and AC power 16 is being supplied, the gas alarm 1 monitors for gas leakage, and when a gas leak occurs, it is detected by the gas circuit breaker 2. A signal is output and the gas cutoff valve 3 is cut off.

When the AC power supply 16 is out of power, the plug 4 and the outlet 14 are connected, so the oscillation signal of the oscillation circuit 5 is transmitted through the power plug 4 and the power outlet 11 to the load 12 such as the pole transformer 14 or the electrical equipment 13. The load 12 attenuates the output level of the oscillation signal.

On the other hand, when the power plug 4 is pulled out from the outlet 11, there is no attenuation in the output path of the oscillation circuit 5. Therefore, the level detection circuit 6 outputs a detection signal only when the plug is pulled out by detecting the difference in the output level of the oscillation circuit 5 between this power outage and when the plug is pulled out, and the gas circuit breaker 2 is driven by the detection signal. Then, the gas cutoff valve 3 is shut off.

Furthermore, when the gas alarm 1 is supplied with DC power 16 through the power outlet 11 and the power plug 4, the energization detection circuit 7 detects this,
The detection output causes the level detection circuit 6 to cut off the detection output to the gas circuit breaker 2. As a result, when the power is on, the output of the detection output of the level detection circuit 6 is cut off regardless of the oscillation output level input to the level detection circuit 6.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, the same parts as in FIGS. 1 and 4 are denoted by the same reference numerals. Inside the gas alarm device 1, a gas alarm main circuit 8 is supplied with power from a power plug, and its output is input to an external output circuit 9. In addition, the output of the oscillation circuit 5 is led out to the power plug 4 through the coupling capacitor _C1 , and the gas alarm main circuit 8
Coupling capacitor
Coupling capacitor C ₂ connected in series with C ₁
The output of the detection circuit 6 is input to the external output circuit 9.

The gas alarm 1 is also provided with an energization detection circuit 7, which detects that AC power 16 is being supplied to the gas alarm 1 through the power plug 4 and outlet 11, and uses the detection output to detect the level detection circuit 7. The output of the detection output to the external output circuit 9 is cut off.

Further, the AC power supply 16 is supplied to the pole transformer 14 through the power outage switch 15, and its secondary voltage is supplied as a general household power supply (AC 100V or 200V). A household electric appliance 13 and a power outlet 11 are connected to this power source, and the electric appliance 13 and the pole transformer 14 act as a load 12 for the output of the oscillation circuit 5. The power outage switch 15 is turned off during a power outage to indicate a power outage state, and although it does not actually exist, it is provided for the purpose of explaining the operation.

In such a configuration, in a steady state in which power is supplied to the power plug 4, power is supplied to the gas alarm 1 through the plug 4, and the main circuit 8 monitors gas leakage. When a gas leak occurs, a detection signal is output from the main circuit 8, which is input to the gas circuit breaker 2 through the external output circuit 9 and is driven to shut off the gas shutoff valve 3.

At this time, the oscillation circuit 5 outputs an oscillation signal. The oscillation signal is connected to a coupling capacitor C ₁ ,
Electrical equipment 13 through plug 4 and outlet 11
The oscillation output level is attenuated by the load 12, resulting in a waveform shown in FIG. 3a.

Further, when the power outage switch 15 is turned off and a power outage occurs, the oscillation circuit 5 continues to output an oscillation signal by the backup power supply 10. This oscillation signal is connected to the coupling capacitor as in the steady state.
Load 1 through C ₁ , plug 4 and outlet 11
2, it is attenuated and its waveform becomes as shown in FIG. 3b, with the same output level as in FIG. 3a.

At this time, the energization detection circuit 7 detects that the gas alarm 1 is not supplied with power from the AC power source 16, and releases the cutoff state of the detection output from the level detection circuit 6 to the external output circuit 9.

On the other hand, when the power plug 4 is pulled out from the outlet 10, the oscillation signal of the oscillation circuit 5 driven by the backup power supply 9 is not supplied to the load 11, and therefore is not attenuated at all. Therefore, the output waveform becomes as shown in FIG. 3c, and the output level becomes higher than that during normal operation and during a power outage.

At this time, the energization detection circuit 7 detects that the gas alarm 1 is not being supplied with power from the AC power supply 16, as in the case of a power outage, and releases the state in which the detection output from the level detection circuit 6 is cut off.

Therefore, the level detection circuit 6 detects the difference in the oscillation signal output level from the oscillation circuit 5 between the power outage and the plug removal to determine whether the power is out or the plug is removed. The detection circuit 6 outputs a detection signal only when the oscillation signal level increases when the plug is pulled out, and the detection signal is inputted to the gas circuit breaker 2 through the external output circuit 9 to shut off the gas circuit breaker 3.

As described above, in the normal state where the gas alarm 1 is supplied with power from the AC power supply 16, the gas circuit breaker 2 is not driven by the detection output from the level detection circuit 6, and only when a gas leak occurs, the gas alarm main circuit is activated. 8 drives the gas circuit breaker 2. Further, in the event of a power outage, the output of the detection output of the level detection circuit 6 is released from the cut-off state, but the attenuated oscillation output of the oscillation circuit 5 is inputted to the level detection circuit 6 through the load 12. Therefore, no detection signal is output from the level detection circuit 6. Furthermore, when the plug is pulled out, the oscillation output level of the oscillation circuit 5 input to the level detection circuit 6 increases, so a detection output is sent out from the level detection circuit 6 to drive the gas circuit breaker 2.

In addition, in the event of a power outage or when the plug is disconnected, the gas alarm 1
Although power is not supplied to the gas alarm main circuit, power is supplied from the backup power supply 10 to the outside of the gas alarm main circuit from then on to compensate for subsequent operation.

FIG. 4 shows a specific example of the configuration of the present invention. In the figure, the oscillation circuit 5 is composed of a transistor Q ₁ , a capacitor C ₃ , a coil L ₁ , etc., and supplies its oscillation output to the power plug 4 and the gas alarm main circuit 8 through a coupling capacitor C ₁ .
The signal is input to the level detection circuit 6 through coupling capacitors C ₁ and C ₂ arranged in series. The level detection circuit 6 includes a rectifier circuit, a smoothing circuit, and a comparator. That is, in a rectifier circuit consisting of an operational amplifier op ₁ and diodes D ₁ and D ₂ , the oscillation output of the oscillation circuit 5 with the coupling capacitors C ₁ and C ₂ fixed is supplied to the non-inverting input of the operational amplifier op ₁ .
Further, a reference voltage is applied to the inverting input of the operational amplifier op ₁ through resistors R ₁ and R ₂ . The output of the rectifier circuit is smoothed by a resistor _R3 and a capacitor _C4 , and the smoothed voltage is supplied to the normal input of the comparator _cp2 . Furthermore, resistors R ₄ , R ₅ and variable resistor VR ₁ are connected in series on the inverting input side, and by connecting the slider of variable resistor VR ₁ to the normal input, the reference voltage set by variable resistor VR ₁ can be adjusted. applied. comparator
The base of a transistor Q ₂ connected to the external output circuit 9 is connected to the output of cp ₂ . The external output circuit 9 includes a light emitting diode D _p and a phototransistor Q _p
Both ends of the light emitting diode _Dp are connected to the detection output of the main circuit 8, and _the cathode is connected to the collector of the transistor _Q2 . Also phototransistor
The output of Q _p is supplied to the gas circuit breaker 2. Furthermore, in the energization detection circuit 7, a signal for determining the energization state obtained from the gas alarm main circuit 8 is connected to a diode.
applied to the base of transistor Q ₃ through D ₃ ,
Its collector is connected to the transistor of the level detection circuit 6.
Connect to the base of _Q2 . Further, a time constant circuit including a capacitor C ₅ and a resistor R ₆ is provided on the base side of the transistor Q ₃ .

In such a configuration, the oscillation circuit 5 is driven and the oscillation output is is coupling capacitor C ₁ and power plug 4,
Since it is supplied to the load 12 via the outlet 11, its output level is attenuated. The oscillation output composes a rectifier circuit in the level detection circuit 6 through coupling capacitors C ₁ and C ₂ .
It is supplied to the normal input of op ₁ , rectified with diodes D ₁ and D ₂ , and smoothed into a DC signal by resistor R ₃ and capacitor C ₄ . This DC signal is applied to the normal input of comparator _cp2 . On the other hand, variable resistance
VR ₁ is comparator cp ₂ during steady state and power outage
The position of the slider is set so that the output is at a low level. Therefore, in this state, if no gas leakage is detected from the main circuit 8, the light emitting diode D _p is off, and no signal is output from the phototransistor Q _p . On the other hand, during normal operation, the gas alarm 1 to the energization detection circuit 7
A signal is output to the gas alarm 1, and when the gas alarm 1 is supplied with power from the AC power supply, the transistor _Q3 of the energization detection circuit 7 is turned on. Therefore, the base potential of the transistor Q ₂ becomes approximately the reference potential, and the transistor Q ₂ is forcibly turned off. As a result, a device that oscillates at a high frequency is connected as the load 12, and the oscillation output level inputted to the operational amplifier op ₁ of the level detection circuit 6 by this device becomes higher than normal, and the positive voltage of the comparator cp ₁ increases. This prevents the transistor Q ₂ from turning on due to an increase in the signal applied to the input input, and prevents the photodiode D _p from emitting light due to the detection output of the level detection circuit 6. That is, when the AC power supply 16 is supplied with electricity, the output of the detection output supplied from the level detection circuit 6 to the gas circuit breaker 2 through the external output circuit 9 is forcibly cut off, so that the load 12 is not connected to a high frequency oscillation device or the like. This prevents malfunctions when connected. In addition, if a gas leak occurs in this energized state, the main circuit 8
From this, the cathode side of the light emitting diode D _p goes into a low state and the light emitting diode D _p emits light. When this emits light, the phototransistor Q _p turns on,
Gas circuit breaker 2 is driven.

Also, when the plug is pulled out, the backup power supply 1
0, the power supply of the gas alarm 1 is backed up and the operating state is maintained. At this time, since the output of the oscillation circuit 5 is not attenuated, the normal input of the comparator cp ₁ rises above the reference voltage applied to the inverting input set by the variable resistor VR ₁ , and the output of the comparator cp ₁ increases.
The output of is inverted to Hi level. Further, since the energization detection circuit 7 is not supplied with a signal from the main circuit 8 for determining power supply from the AC power supply 16, the transistor _Q3 is in an off state. Therefore, the transistor _Q2 of the level detection circuit 6 turns on, and the light emitting diode
D _p is turned on regardless of the detection output from the main circuit 8, the phototransistor Q _p is turned on, and the gas circuit breaker 2 is driven. Note that the time constant circuit using the resistor R ₆ and capacitor C ₅ provided in the energization detection circuit 7 operates when the power plug 4 is pulled out from the outlet 11 and the gas circuit breaker 2 is activated, and then the plug is inserted into the outlet 11 again. Even if the main circuit 8 outputs a power supply determination signal to the energization detection circuit 7, it takes a predetermined period of time until the on-voltage of the transistor _Q3 rises due to the time constant of the capacitor _C5 and the resistor _{R6 .} remains off. This allows you to connect outlet 1 again after pulling out the plug.
1, the transistor Q ₂ is immediately turned off, the operation of the external output circuit 9 is stopped, and the gas circuit breaker 2 is prevented from being restored. Furthermore, when the plug is pulled out from the time of energization, the discrimination signal is no longer supplied from the main circuit 8, but there is a predetermined period of time until the charge in the capacitor _C5 is discharged through the resistor _R6 and the base-emitter path of the transistor _Q3. Keep transistor _Q3 on. As a result, when the plug 4 is pulled out, the transistor Q ₂ is turned off for a predetermined period of time, and the external output circuit 9 is activated to prevent the gas circuit breaker 2 from being driven.
The gas circuit breaker 2 is prevented from being driven for short-term plug pulling actions other than self-inflicted actions.

〔effect〕

As described above, according to the present invention, even if the power plug and the power outlet are connected by an extension cord, the gas cutoff valve can be shut off when the plug is pulled out due to self-damage. In addition, it is possible to distinguish between a power outage and a time when the plug is removed, and the gas cutoff valve can be shut off only when the plug is removed.

In addition, under normal conditions when a gas alarm is powered from an AC power source, the detection output from the level detection circuit is forcibly cut off. Malfunctions can be prevented.

Furthermore, the detection operation is not uncertain depending on the shape of the outlet, and pulling out of the plug can be detected reliably.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the principle of the gas alarm device according to the present invention, Fig. 2 is a diagram showing an embodiment of the invention, and Figs. 3 a to c show oscillation signal waveforms of the number of oscillations in Fig. 2. 4 are circuit diagrams showing a specific example of the present invention, and FIG. 5 is a diagram showing a conventional gas alarm device. 1...Gas alarm, 2...Gas circuit breaker, 3...
Gas cutoff valve, 4... Power plug, 5... Oscillation circuit, 6... Level detection circuit, 7... Energization detection circuit, 8... Gas alarm main circuit, 9... External output circuit, 10... Backup Power supply, 11...Power outlet, 12...Load, 13...Electrical equipment, 1
4...Pole transformer, 15...Power outage switch, 1
6...AC power supply, _C1 , _C2 ...coupling capacitor.

Claims (1)

[Scope of claim for utility model registration] Gas alarm that detects leakage of gas supplied by plugging the power plug into the power outlet of an AC power supply to which loads such as pole transformers and electrical equipment are connected in parallel. In the gas leak alarm device, the gas alarm includes an oscillation circuit and a level detection circuit that detects the output level of the oscillation circuit. and an energization detection circuit that detects that the gas alarm is being supplied with power from the AC power supply and controls the output of the transfer output of the level detection circuit based on the detection output, and the oscillation circuit has an output that is The output level of the oscillation circuit derived from the power plug is detected by the level detection circuit during a power outage and when the power plug is pulled out from the power outlet, and the level detection circuit detects only when the power plug is pulled out from the power outlet. The gas circuit breaker is configured to be driven by the output, and the detection output of the energization detection circuit is configured to cut off the detection output of the level detection circuit to the gas circuit breaker when the gas alarm is powered from an AC power source. A gas leak alarm device characterized by: