JP3465175B2 - Fire alarm - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire alarm, and more particularly to a thermal fire alarm for homes and homes.

[0002]

2. Description of the Related Art Conventional thermal fire alarms for home use often use dry batteries as a power source. Therefore, the fire alarm is equipped with a low voltage warning circuit,
The voltage drop warning circuit monitors the voltage of the dry battery, and when the voltage drops to a predetermined value, a built-in buzzer sounds to give an alarm. Such a fire alarm device is disclosed in Japanese Patent Publication No. 58-31276.

[0003]

In the conventional thermal fire alarm as described above, when the battery voltage drops, the built-in buzzer automatically sounds to give an alarm. The alarm signal oscillation circuit may be installed to make the buzzer sound intermittently. However, there is a problem that the current consumption is large because it is in a state of being operated immediately.

The present invention has been made in order to solve such a problem, and only when a battery voltage drop is detected, the alarm signal oscillation circuit of the voltage drop alarm circuit is operated to intermittently ring the buzzer, The purpose is to obtain a fire alarm that consumes less current.

[0005]

A fire alarm device according to the present invention is driven by a battery power source, and when a fire is detected, the fire alarm device drives the alarm device, and a voltage monitor for detecting the voltage of the battery power source. A voltage drop warning circuit comprising a circuit and a warning signal oscillating circuit for periodically generating a warning signal based on the voltage of the battery power source and outputting the warning signal to the warning device drive circuit when the detected value is less than or equal to a predetermined value, A time limit timer is provided for shutting off a desired time during operation between the battery power source and the voltage drop warning circuit.

[0006]

[0007]

[0008]

[0009]

[0010]

1 is a block diagram showing a configuration of a fire alarm device according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a configuration of a low voltage alarm circuit of the fire alarm device, and FIG. It is a circuit diagram which shows the structure of the buzzer drive circuit of the fire alarm device.
In the figure, 1 is a fire detection circuit composed of a thermistor which is a heat sensitive element and a voltage circuit which outputs an output voltage corresponding to increase / decrease in resistance value of the thermistor, 2 is a voltage output from the fire detection circuit 1, which is a predetermined reference value A fire determination circuit that outputs an alarm signal at the above time, 3 is a buzzer drive circuit that is an alarm drive circuit that receives an alarm signal from the fire determination circuit 2, and outputs a buzzer drive signal (alarm drive signal), 4 is a buzzer drive A buzzer, which is an alarm device driven by a buzzer drive signal of the circuit 3, 5 is a battery that is a power source for driving various circuits and devices such as the fire detection circuit 1, the fire determination circuit 2, and 6 is connected in series to the battery 5. This is the power switch.

Reference numeral 7 is a voltage drop alarm circuit which detects the voltage of the battery 5 and outputs an alarm signal to the buzzer drive circuit 3 when the detected value is below a predetermined value. The voltage drop warning circuit 7 detects the voltage of the battery 5 and outputs the voltage of the battery 5 only when the detected value is a predetermined value, for example, 5.1 V or less.
And a warning signal oscillation circuit 9 that periodically generates a warning signal based on the voltage of the battery 5 output by the voltage monitoring circuit 8 and outputs the warning signal to the buzzer drive circuit 3. Reference numeral 10 is a time limit timer provided between the battery 5 and the low voltage warning circuit 7 for cutting the energization during operation for, for example, 6 hours, and 11 is a circuit except the buzzer 4, the buzzer drive circuit 3, and the low voltage warning circuit 7. A constant voltage circuit for supplying a constant voltage that does not fluctuate according to the voltage of the battery 5, 12 is an inspection switch, 13
Is an inspection circuit that outputs a fire pseudo signal to the fire detection circuit 1 when the inspection switch 12 is on, and 14 is a timer circuit that is activated when the string alarm stop switch 15 is turned on and outputs an alarm stop signal for a predetermined time. .

In FIG. 3, reference numeral 20 denotes an AND gate 20 of the buzzer drive circuit 3, the first input terminal of which is connected to the output side of the fire judging circuit 2 and the second input terminal of which is the output side of the timer circuit 14. It is connected to the. Reference numeral 21 denotes a transistor for driving the buzzer 4, the collector of which is connected to the positive side of the battery 5 via the buzzer 4, the emitter of which is connected to the negative side of the battery 5 and the base of which is for blocking backflow through the resistor 22. First and second diodes 23, 24 of
Is connected to the cathode. The anode of the first diode 23 is connected to the output terminal of the AND gate 20, and the anode of the second diode 24 is connected to the output side of the voltage drop warning circuit 7. In this way, the buzzer drive circuit 3
Is composed of an AND gate 20 to a second diode 24.

Next, the operation of the fire alarm device according to the embodiment of the present invention will be described. For example, the thermistor of the fire detection circuit 1 of the fire alarm installed on the ceiling of the room senses the heat in the room, and the voltage circuit of the fire detection circuit 1 converts the resistance change due to the heat of the thermistor into a voltage change. The voltage value is output to the fire determination circuit 2. The fire determination circuit 2 outputs an alarm signal to the buzzer drive circuit 3 when the voltage output from the fire detection circuit 1 is equal to or higher than a predetermined reference value. The reference value of the fire judgment circuit 2 is that the room temperature is, for example, 60 due to a fire.
The voltage is set to the same voltage as the voltage output from the voltage circuit of the fire detection circuit 1 when the temperature reaches a certain level. In the buzzer drive circuit 3 which has received the alarm signal, the H state of the alarm signal is input to the first input terminal of the AND gate 20, and the second input terminal of the AND gate 20 does not operate from the timer circuit 14. Since the H-state signal that is always output is input, the output terminal of the AND gate 20 outputs the H-state signal. The signal is applied to the base of the transistor 21 via the first diode 23 and the resistor 22. Then, the transistor 21 is turned on, the collector and the emitter are conducted, and the buzzer 4 continuously sounds to warn of a fire. In addition, when the room temperature is 60 degrees or less, the buzzer 4 is not sounded and is in a monitoring state.

As described above, the buzzer 4 sounds when a fire is detected, but the buzzer 4 also sounds even when the inspection switch 12 is turned on and a fire pseudo signal is output from the inspection circuit 13 to the fire detection circuit 1. Can be inspected. The buzzer 4 does not need to be sounded forever when a fire is detected or in the case of a pseudo fire, and it is necessary to set the buzzer 4 in the monitoring state. The timer is operated so as to return to. The operation of such a timer is
When the alarm stop switch 15 is turned on, the timer circuit 14 is activated and outputs an alarm stop signal in the L state to the buzzer drive circuit 3 for 5 minutes, for example. Then, the buzzer drive circuit 3
Since the alarm stop signal in the L state is input to the second input terminal of the AND gate 20, the output terminal of the AND gate 20 outputs the signal in the L state, the transistor 21 is turned off, and the collector-emitter is disconnected. Even if the alarm signal is input from the fire determination circuit 2 to the buzzer drive circuit 3 due to non-conduction, the buzzer drive circuit 3 stops the buzzer 4 from ringing for 5 minutes, and the original monitoring state is maintained after 5 minutes have passed. Return to. The timer operating time is set to 5 minutes because it is sufficient time for the thermistor to return to normal temperature when it is warmed by a rapid heating operation, for example.

Next, the operation of the low voltage warning circuit 7 in the monitoring state of the fire alarm will be described. The voltage monitoring circuit 8 of the low voltage warning circuit 7 constantly monitors and detects the voltage of the battery 5, and the voltage of the battery 5 is output only when the detected value is a predetermined value of 5.1 V or less. Output to. The alarm signal oscillating circuit 9 periodically generates an alarm signal in the H state based on the voltage of the battery 5 to output the buzzer driving circuit 3
Output to. The H-state alarm signal input to the buzzer drive circuit 3 is applied to the base of the transistor 21 via the second diode 24 and the resistor 22. Then, the transistor 21 is turned on, the collector and the emitter are conducted, and the buzzer 4 sounds to warn of the battery voltage drop. The buzzer sounding time for the alarm of the voltage drop of the battery 5 is, for example, about 1
It is 20 ms, and the cycle is, for example, about 10 to 15 seconds.
The buzzer 4 sounds intermittently in this manner because the alarm signal oscillation circuit 9 outputs the alarm signal in the H state at the above-mentioned cycle. In this way, the alarm signal oscillating circuit 9 of the voltage drop alarm circuit 7 is operated by being applied by the voltage monitoring circuit 8 only when the voltage of the battery 5 is equal to or lower than the predetermined value of 5.1 V, and the alarm signal in the H state is output. Since the alarm signal is generated and output to the buzzer drive circuit 3, and the alarm signal generated is periodically output, the consumption current can be significantly reduced and the life of the battery 5 can be extended.

When the voltage of the battery 5 drops in the operating state of the fire alarm timer circuit 14, the voltage drop warning circuit 7 operates to output an alarm signal to the buzzer drive circuit 3 to make the buzzer 4 ring. The alarm signal of the low voltage warning circuit 7 is used as the alarm signal of the fire determination circuit 2 by using, for example, an OR gate composed of two backflow prevention diodes 23 and 24 for the transistor 21 that drives the buzzer 4 in the buzzer drive circuit 3. Is input via a different route, the timer circuit 14 operates to output an alarm stop signal and the AND gate 20 of the buzzer drive circuit 3 does not output an alarm signal. A low battery voltage warning can be activated.

Further, since the power switch 6 is provided, it is sufficient to turn off the power switch 6 when the user goes out for a long period of time and the alarm of the voltage drop of the battery 5 is unnecessary. Further, for example, when the alarm for the low voltage is not needed during sleep, the time limit timer 10 is operated with the power switch 6 turned on, and the battery 5 is charged for 6 hours from 12:00 in the evening to 6:00 in the morning, for example. If the battery 5 and the voltage drop alarm circuit 7 are disconnected from each other, the voltage drop alarm circuit 7 does not operate even if the battery 5 drops below a predetermined voltage value, and the consumption current can be further reduced.
The life of the battery 5 will be extended further.

In the above embodiment, the fire detection circuit 1 is a thermal fire alarm using a thermal type, but the fire detection circuit 1
It goes without saying that the present invention can be applied to flame-type and smoke-type fire alarms using flame-type and smoke-type fire alarms.

[0019]

As described above, according to the present invention, the voltage monitoring circuit detects the voltage of the power supply battery for driving equipment such as the fire detection circuit and the fire determination circuit, and the voltage drop alarm circuit detects the detected value. Outputs the voltage of the battery power when the value is below the specified value,
The alarm signal oscillation circuit of the voltage drop alarm circuit periodically generates an alarm signal based on the voltage of the battery power source and outputs it to the alarm device drive circuit, and the alarm device intermittently issues an alarm by the alarm device drive circuit. When it is found that the voltage of the battery power supply has dropped, and when it is not necessary to warn of a voltage drop, the time limit timer is operated for the desired time and the battery power supply and the voltage drop alarm circuit are shut off during that time. Even if the voltage of the battery drops below a predetermined voltage value, the voltage drop alarm circuit does not operate, the consumption current can be further reduced, and the life of the power supply battery can be further extended.

[0020]

[0021]

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a fire alarm device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a voltage drop alarm circuit of the fire alarm device.

FIG. 3 is a circuit diagram showing a configuration of a buzzer drive circuit of the fire alarm device.

[Explanation of symbols]

1 Fire detection circuit 2 Fire judgment circuit 3 Buzzer drive circuit (alarm drive circuit) 4 buzzer (alarm) 7 Low voltage alarm circuit 10 time limit timer 14 Timer circuit

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Claims (2)

(57) [Claims] 1. A fire alarm device that is driven by a battery power source and drives an alarm device when a fire is detected. In the fire alarm device, a voltage monitoring circuit that detects the voltage of the battery power source, and when the detected value is a predetermined value or less , A voltage drop warning circuit comprising a warning signal oscillating circuit that periodically generates a warning signal based on the voltage of the battery power source and outputs the warning signal to the warning device drive circuit,
Desired during operation between the battery power supply and the voltage drop warning circuit
A fire alarm equipped with a time limit timer that cuts off time . 2. The alarm signal oscillating circuit includes the voltage monitor.
Marked only when the voltage of the battery is below the specified value by the visual circuit.
The fire alarm device according to claim 1, wherein the fire alarm device operates in addition to the above .