JPH08166348A - Fire alarm - Google Patents

Abstract

PURPOSE: To return a fire alarm to the normal monitoring state after a predetermined time and surely sense smoke by activating a timer circuit when an acoustic stop switch is ON, and stopping the alarm and also the operation of a one shot circuit for a set time. CONSTITUTION: When a fire is decided by a fire judgement circuit 4 and a buzzer 6 is sounded, a string is pulled to turn ON an acoustic stop switch 10. As a result, a pulse signal is generated from a one shot circuit 11 and a timer circuit 12 is activated to output a signal stopping the sounding of the buzzer 6 for a preset time (approximately 5 minutes) to the circuit 4. if the smoke entering a smoke introduction room first is a transient one, the smoke goes out from the room in a predetermined time, so that the room is turned to a level not reaching a fire. The buzzer 6 is consequently not sounded again. A predetermined time later after the switch 10 is first turned ON, the fire alarm is returned to the ordinary monitoring state to sound the buzzer 6 when detecting a normal fire. Smoke can thus be surely detected at all times.

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 fire alarm for homes and homes.

[0002]

2. Description of the Related Art A conventional fire alarm of this type, for example, a photoelectric fire alarm, includes a light emitting element and a light receiving element in a smoke inflow chamber surrounded by a labyrinth so that direct light from the light emitting element does not enter the light receiving element. , And the light emitting element emits light intermittently,
A light receiving element receives the light scattered by the smoke flowing into the smoke inflow chamber surrounded by the labyrinth, and the fire is detected based on the output of the light receiving element.In the event of a fire, a buzzer in the alarm It was supposed to sound a fire.

Further, in order to prevent the buzzer in the alarm from repeatedly ringing due to transient smoke generated by other than a fire such as a cigarette, conventionally, when the buzzer rings, the ringing of the buzzer is performed. A string for stopping is attached to the alarm body, and when the string is pulled, the timer circuit determines for a predetermined time (when transient smoke flows into the smoke inflow chamber surrounded by the labyrinth, the smoke is judged to be a fire. The time to reach a level that is not controlled, in other words, the time it takes for the smoke once flowing into the labyrinth to flow out of the labyrinth, eg 5
For a minute) was supposed to stop the buzzer ringing.

[0004]

In the conventional fire alarm as described above, when the buzzer sounds, the timer circuit is activated each time the cord attached to the alarm body is pulled. When the string is pulled many times, the buzzer stops ringing for a predetermined time, for example, 5 minutes from the last time the string was pulled. Therefore, if transient smoke flows into the smoke inflow chamber surrounded by the labyrinth, the buzzer sounds, and the string is pulled several times, even if the inflowing smoke reaches a level that is not judged to be a fire, There was a problem that the buzzer stopped ringing, and the buzzer could not ring even though the fire could be detected normally.

The present invention has been made in order to solve such a problem, in which transient smoke flows into a smoke inflow chamber surrounded by a labyrinth, a buzzer sounds, and a string causes the sound to be generated. Even if it is stopped, if the inflowing smoke reaches a level where it is not judged as a fire, that is, if the predetermined time by the timer circuit elapses from the time when the string is pulled for the first time, the normal monitoring state is entered and the smoke detection The purpose is to obtain a fire alarm that is reliably performed.

[0006]

A fire alarm device according to the first invention detects a fire phenomenon and outputs an electric signal based on the fire phenomenon, and a fire detection circuit based on the output signal of the fire detection circuit. Fire judgment circuit that outputs a warning signal to drive an alarm device when a fire is judged,
When the alarm signal is output from the fire determination circuit, the one-shot circuit that outputs a pulse signal when the sound stop switch is turned on, and the output pulse signal of the one-shot circuit is activated, and during the preset time, The timer circuit outputs a signal for stopping the output operation of the alarm signal to the fire determination circuit and outputs a signal for stopping the operation of the one-shot circuit to the one-shot circuit.

In the fire alarm device according to the second aspect of the present invention, the one-shot circuit outputs a pulse signal when the on-state of the acoustic stop switch continues for a predetermined time.

[0008]

In the first aspect of the invention, the fire detection circuit
A fire phenomenon is detected, an electric signal based on the fire phenomenon is output, and a fire determination circuit determines a fire based on the output signal of the fire detection circuit, and an alarm that drives an alarm device when a fire is determined When the signal is output and the one-shot circuit outputs an alarm signal from the fire determination circuit, a pulse signal is output when the sound stop switch is turned on, and the timer circuit activates the output pulse signal of the one-shot circuit. However, during the preset time, a signal for stopping the output operation of the alarm signal is output to the fire determination circuit, and a signal for stopping the operation of the one-shot circuit is output to the one-shot circuit.

In the second aspect of the invention, the one-shot circuit outputs a pulse signal when the on-state of the acoustic stop switch continues for a predetermined time.

[0010]

1 is a block diagram showing the construction of a fire alarm device according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an oscillation and light emitting circuit for intermittently emitting a light emitting diode as a light emitting element. In this embodiment, a pulse current, a pulse width and a pulse period which flow through the light emitting diode of the oscillation and light emitting circuit 1 are respectively about 0.8. A, 70 μsec, 3 sec. Reference numeral 2 is a clock signal generation circuit for generating a clock pulse signal synchronized with the intermittent light emission period of the light emitting diode by the oscillation and light emission circuit 1, and the pulse width and pulse period of the clock pulse signal generated by this clock signal generation circuit 2. Are 70 μsec and 3 sec, respectively.

Reference numeral 3 denotes a photodiode which is a light receiving element for converting an optical signal of the light emitting diode of the oscillation and light emitting circuit 1 into an electric signal pulse, an amplifier circuit for amplifying the electric signal pulse of the photodiode, and an amplifier circuit amplifies the signal. A light receiving and amplifying circuit including a threshold circuit that outputs a pulse signal only when the electric signal pulse is equal to or more than a predetermined reference value. The oscillation and light emitting circuit 1 and the light receiving and amplifying circuit 3 constitute a fire detection circuit.

The light emitting diode of the oscillation and light emitting circuit 1 and the photodiode of the light receiving / amplifying circuit 3 do not directly reach the photodiode in the smoke inflow chamber (not shown) surrounded by the labyrinth. When smoke enters the smoke inflow chamber, the particles emitted from the smoke scatter and reflect the light emitted from the light emitting diode and reach the photodiode.

Reference numeral 4 is a fire judging circuit for outputting an alarm signal based on the output clock pulse signal of the clock signal generating circuit 2 and the output signal of the light receiving and amplifying circuit 3. In this embodiment, the output of the clock signal generating circuit 2 is outputted. An alarm signal is output when the output signal of the light receiving amplifier circuit 3 synchronized with the clock pulse signal continues three times. In addition, the conditions for the fire determination circuit 4 to output an alarm signal are:
The alarm signal is output not only when the output signal of the light receiving and amplifying circuit 3 continues three times, but also when the output signal of the light receiving and amplifying circuit 3 is output once, twice, or three or more times a predetermined number of times. Good.

Reference numeral 5 is a buzzer drive circuit which is an alarm drive circuit for receiving an alarm signal from the fire judging circuit 4 and outputting an alarm drive signal, and 6 is an alarm drive driven by the alarm drive signal from the buzzer drive circuit 5. There is a buzzer. 7 is a voltage drop alarm circuit that outputs an alarm signal to the buzzer drive circuit 5 when the battery voltage of the fire alarm device is low, and 8 is a pseudo electrical signal that is output to the light receiving and amplifying circuit 3 when the inspection switch 9 is turned on. It is an operation inspection circuit.

Numeral 10 stops the driving when smoke from a fire or transient smoke other than the smoke generated during a fire is generated, an alarm signal is output from the fire judging circuit 4, and the buzzer 6 is driven. This is an acoustic stop switch for switching the switch by pulling a string attached to the alarm device body. Reference numeral 11 is a one-shot circuit that outputs a falling pulse by the switching operation of the sound stop switch 10. Reference numeral 12 is a one-shot circuit 11
It is started by the output pulse of, and it is a predetermined time (for example, 5 minutes)
Is a timer circuit that stops driving the buzzer 6 during
The timer operation is activated, and the one-shot circuit 11 is prevented from outputting a falling pulse during the timer operation so that the timer operation is not restarted.

Reference numeral 13 is a constant voltage circuit for supplying a constant voltage VDD to the light emitting circuit 1, the clock signal generating circuit 2, the light receiving and amplifying circuit 3, the fire judging circuit 4, the operation checking circuit 8, the one-shot circuit 11 and the timer circuit 12. Is.

Next, the operation of the fire alarm device according to the embodiment of the present invention will be described. First, in a monitoring state in which smoke does not enter the smoke inflow chamber, the oscillation and light emitting circuit 1 intermittently emits light from the light emitting diode with a pulse width of 70 μsec and a pulse period of 3 sec, and the clock signal generation circuit 2
Is the pulse width synchronized with the intermittent light emission of the light emitting diode 7
The clock pulse signal with 0 μsec and pulse period of 3 sec is output to the fire judgment circuit 4.

Since no smoke is contained in the smoke inflow chamber, almost no light emitted by the light emitting diode reaches the photodiode of the light receiving and amplifying circuit 3 in the smoke inflow chamber,
The electric signal pulse obtained by amplifying the output signal of the photodiode is below a predetermined reference value, and the pulse signal of the threshold circuit of the light receiving / amplifying circuit 3 is not output.
Therefore, the fire determination circuit 4 does not output an alarm signal,
The buzzer drive circuit 5 also does not output an alarm drive signal to the buzzer 6, and the buzzer 6 does not ring.

Next, in a fire condition in which smoke enters the smoke inflow chamber, the light emitted by the light emitting diode of the oscillation and light emitting circuit 1 is scattered and reflected by the particles of the smoke entering the smoke inflow chamber, and the light receiving and amplifying circuit. Since it reaches the second photodiode, the electric signal pulse obtained by amplifying the output signal of the photodiode becomes a predetermined reference value or more, and the pulse signal of the threshold circuit of the light receiving and amplifying circuit 3 is output. When the fire judging circuit 4 judges that there is a fire based on the input pulse signal and the output clock pulse signal of the clock signal generating circuit 2, an alarm signal is output, and the buzzer driving circuit 5 causes the buzzer 6 to An alarm drive signal is output and the buzzer 6 sounds.

Next, the operations of the one-shot circuit 11 and the timer circuit 12 will be described. FIG. 2 is a circuit diagram showing an example of the one-shot circuit 11 and the timer circuit 12, and FIG. 3 is a waveform diagram for explaining the operation of the one-shot circuit 11 and the timer circuit 12. In the figure, 20 to 31 are resistors, 40 to 44 are capacitors, 50 and 51 are AND circuits, 52 is a NAND circuit, 60 is a timer IC, and 61 and 6
Reference numeral 2 is a terminal for changing the timer time of the timer IC 60. When the timer circuit 12 is tested, the timer time can be shortened by connecting a resistor between the terminals 61 and 62.

Now, the test of the timer circuit 12 will be described. The test of the timer circuit 12 means that the buzzer 6 sounds after the fire alarm detects a fire, and then the sound stop switch 10 is operated, and then the buzzer 6 continues for a predetermined time set by the timer circuit 12. This is a test for testing whether or not the sound re-rings, and after a predetermined time, to see if it is definitely in the monitoring state.

Next, this test method will be described. First, shorten the timer time between the terminals 61 and 62, for example, 10
Connect a resistor with a resistance set to be a few seconds. Then, the inspection switch 9 of the operation inspection circuit 8 is continuously pressed to turn on the switch. As a result, the same state as a fire is artificially created, so that the fire determination circuit 4 operates and the buzzer 6 sounds. Here, the sound stop switch 1
0 is turned on to stop the buzzer 6 from ringing. As a result, the timer circuit 12 operates, and the predetermined time (10
During a few seconds, the timer circuit 12 stops the ringing of the buzzer 6. After 10 seconds, the operation check switch 9 continues to be pressed, that is, is in the ON state, so that the fire determination circuit 4 is operated again. Therefore, the buzzer 6 will ring again.

It should be noted that the predetermined time set by the timer circuit 12 is tested while measuring the time using a measuring device such as a stopwatch. By such a method, the timer circuit 12 is tested, and two sound stop switches 10 and operation check switches 9 are provided, and the operation check switch 9 is continuously pressed to perform the test.
The specified time set from 2 can be accurately measured, and
The test of the timer circuit 12 can be performed in a short time by providing the terminals 60 and 61 and connecting a resistor for shortening the timer time between them to perform the test. Reference numeral 70 denotes a + power supply line connected to the output terminal of the constant voltage circuit 13, to which a constant voltage VDD is supplied. 71 is a GND line connected to the "-" terminal of the battery.

The "OUT" terminal of the timer IC 60 is normally at "H" level, and when the falling pulse is input to the "Set" terminal from the one-shot circuit 11, the timer is started and the resistors 28, 29 and During the timer time determined by the capacitor 42, the output of the "Out" terminal is "L".
The output from the "Out" terminal is input to the fire determination circuit 4 and serves as a signal for stopping the driving of the buzzer 6. Also, "Reset" of the timer IC 60
The terminal is pulled up internally, and when the power is turned on, the capacitor 43 causes the "Reset" terminal to
An L "level signal is input to enter the reset state, after which it becomes" H "and the timer IC 60 becomes operable.
Further, the capacitor 44 is provided so that the voltage at the point (g) in FIG. 2 is set to 0 when the power is turned on and the malfunction when the power is turned on is eliminated.

First, the AND circuit 50 of the one-shot circuit 11 has a "
The H level signal is input, and in the normal monitoring state in which the fire determination circuit 4 does not determine a fire, the AND circuit 50 inputs the L level signal. Therefore, the signal from the sound stop switch 10 is not output from the AND circuit 50, and only when the fire determination circuit 4 determines a fire, the one-shot circuit 1
An output pulse is output from 1.

Then, after the smoke judging circuit 4 judges that the smoke is a fire or a smoke other than the smoke generated at the time of the fire, the sound stop switch 10 is activated at a certain time t0.
When the switch is turned on by pulling the string attached to the alarm body, the voltage at point (a) in FIG.
The voltage changes to VDD as shown in (a).

Then, since the capacitor 40 is charged by the current flowing through the resistor 20, the voltage at the point (b) in FIG. 2 gradually increases as shown in FIG. The voltage is divided by the resistor 21 and rises to the voltage applied to the resistor 21, and this voltage is set to be higher than the voltage that the AND circuit 50 recognizes as the "H" level. Further, the resistor 21 is adapted to flow a current from the capacitor 40 in order to discharge the electric charge stored in the capacitor 40 when the acoustic stop switch 10 is turned off.

When the voltage at the point (b) in FIG. 2 gradually increases as shown in (b) in FIG. 3, the fire judging circuit 4 judges that there is a fire, so the AND circuit 50 The "H" level signal is input to one of the input terminals, and the voltage at the point (b) in FIG.
When 0 becomes the voltage which is judged to be the "H" level, the output of the AND circuit 50 becomes the "H" level, and the voltage at the point (c) in FIG. 2 is at time t1 as shown in (c) in FIG. It becomes the voltage of VDD. As described above, the capacitor 40 prevents the AND circuit 50 from outputting when the on-state of the acoustic stop switch 10 is (t1 -t0) or less, and this operation causes the acoustic stop switch 10 to momentarily stop. It does not operate just by turning on the switch, and the one-shot circuit 11 does not operate due to chattering of the sound stop switch 10 and other noises.

When the voltage at point (c) in FIG. 2 changes as shown in FIG. 3 (c), the voltage at point (d) in FIG. (D)
The voltage becomes VDD at the time t1, and the capacitor 41 is charged thereafter, so that the voltage gradually decreases. The voltage at the point (c) in FIG. 2 is input to one input terminal of the AND circuit 51, and AN
Since the voltage at the point (d) in FIG. 2 is input to the other input terminal of the D circuit 51, the output of the AND circuit 51 becomes the “H” level at the time t1 and the voltage at the point (d) in FIG. When the voltage at the point becomes the voltage which the AND circuit 51 determines to be at the "L" level at time t2, it becomes the "L" level.

Therefore, the voltage at the point (e) in FIG. 2 becomes a pulse having a pulse width of (t2-t1) as shown in (e) of FIG. Thus, by inputting the voltage at point (c) in FIG. 2 and the voltage at point (d) in FIG. 2 to the AND circuit 51, a pulsed voltage is output.
A pulse having a predetermined pulse width is output when the output of the D circuit 50 is in the "H" level state.
By this operation, the one-shot circuit 11 is prevented from operating due to the influence of noise and the like, and a pulse having a constant width is output to the timer circuit 12, so that the timer can be surely started. ing.

The output of the "Out" terminal of the timer IC 60 is input to one input terminal of the NAND circuit 52, and the AND output is input to one input terminal of the NAND circuit 52.
When the output signal of the circuit 51, that is, the signal shown in (e) of FIG. 3 is input and the timer of the timer IC 60 is not activated, the output of the NAND circuit 52 is “H” level. As shown in (f) of FIG. 3, it becomes a falling pulse.

Since the output of the NAND circuit 52 is input to the "Set" terminal of the timer IC 60, the timer of the timer IC 60 is activated by the falling pulse as shown in (f) of FIG. Then, when the timer is activated, the output of the "Out" terminal of the timer IC 60 becomes "L" level during the timer time determined by the resistors 28 and 29 and the capacitor 42, and the signal is the fire determination circuit 4
Is input to stop the driving of the buzzer 6. At this time, the sound stop switch 10 may be turned off.

The output of the "Out" terminal of the timer IC 60 is also input to one of the output terminals of the NAND circuit 52, and the timer I of the timer IC 60 is operating.
Since the output of the "Out" terminal of C60 is "L" level,
The output of the NAND circuit 52 is always at the “H” level regardless of the output of the AND circuit 51.
Even if the sound stop switch 9 is turned on, the timer IC 60 is not restarted while the timer is running. The timer IC 60 is always determined by the resistors 28 and 29 and the capacitor 42 after the timer is started. Timer operation is terminated after the elapse of the timer time,
The output of the “ut” terminal becomes “H” level.

When the timer operation of the timer IC 60 is finished and the output of the "Out" terminal of the timer IC 60 becomes "H" level, the normal monitoring state is established, and if smoke due to fire exists in the smoke inflow chamber. The fire judging circuit 4 judges that there is a fire, and the buzzer 6 is driven to give an alarm. At this time, transient smoke other than the smoke generated during a fire is generated, the fire judgment circuit 4 judges that the fire is a fire, the buzzer 6 is driven, and the string is pulled to turn on the sound stop switch 10 to turn on the buzzer. If the timer time set in the timer IC 60 elapses after the driving of 6 is stopped, the transient smoke that first flows into the smoke inflow chamber is
Since it has flowed out of the smoke inflow chamber and has reached a level at which it is not judged to be a fire, the buzzer 6 will not be driven again by the transient smoke that is initially judged to be a fire.

In this embodiment, after the sound stop switch 10 starts the timer of the timer IC 60 of the timer circuit 12, the sound stop switch 10 does not restart the timer IC 60 during the timer operation of the timer IC 60. After the transient smoke flows into the smoke inflow chamber through the labyrinth and the buzzer sounds, even if the string is pulled several times, if the inflow smoke reaches a level at which it cannot be judged as a fire, that is, If a predetermined time by the timer IC 60 elapses from the time when the sound stop switch 10 is pulled at the beginning, it is possible to return to the normal monitoring state and the fire alarm is in a state where normal fire detection can be performed. It is possible to reliably detect smoke without the buzzer not ringing.

In this embodiment, a photoelectric fire alarm device equipped with a fire detection circuit for detecting smoke as a fire phenomenon using a light emitting element such as a light emitting diode and a photodiode and a light receiving element has been described. A thermal fire alarm equipped with a fire detection circuit that detects heat as a fire phenomenon using a temperature sensor (for example, a thermistor) that detects the temperature of, a sensor that detects the ultraviolet or infrared component peculiar to the flame that occurs during a fire ( For example, a flame-type fire alarm equipped with a fire detection circuit that detects a flame as a fire phenomenon using a pyroelectric element and a gas detection circuit that uses a gas sensor that detects gas generated during a fire and that detects gas as a fire phenomenon. The present invention may be applied to a gas fire alarm provided with the above. Further, in this embodiment, a battery (not shown) is used as a power source, but an AC power source may be used by providing a rectifying circuit.

[0037]

As described above, according to the first aspect of the invention, the one-shot circuit outputs the pulse signal when the sound stop switch is turned on while the alarm signal is being output from the fire determination circuit, and the timer signal is output. The circuit activates the output pulse signal of the one-shot circuit, outputs a signal to stop the output operation of the warning signal to the fire judgment circuit for a preset time, and a signal to stop the operation of the one-shot circuit. Since it is output to the one-shot circuit, once the pulse signal is output from the one-shot circuit, the timer circuit is activated and the timer circuit is operating, and the alarm signal output operation of the fire determination circuit is stopped, The operation of the one-shot circuit stops, the pulse signal is not output, and the timer circuit does not restart. Without signal output operation is stopped, an effect that can be reliably performed smoke.

According to the second aspect of the invention, the one-shot circuit outputs the pulse signal when the ON state of the acoustic stop switch continues for a predetermined time. Therefore, the acoustic stop switch may malfunction or may be affected by noise. It is possible to more reliably perform smoke detection without the alarm signal output operation of the fire determination circuit being stopped by the careless activation of the timer circuit.

[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 an example of a one-shot circuit 11 and a timer circuit 12.

FIG. 3 is a waveform diagram for explaining operations of the one-shot circuit 11 and the timer circuit 12.

[Explanation of symbols]

 1 Oscillation and light emission circuit (fire detection circuit) 3 Light receiving amplification circuit (fire detection circuit) 4 Fire judgment circuit 6 Buzzer (alarm) 10 Sound stop switch 11 One-shot circuit 12 Timer circuit

Claims (2)

[Claims] 1. A fire detection circuit that detects a fire phenomenon and outputs an electrical signal based on the fire phenomenon, and a fire determination circuit based on the output signal of the fire detection circuit. A fire determination circuit that outputs an alarm signal that drives the one-shot circuit, and a one-shot circuit that outputs a pulse signal when the sound stop switch is turned on while the alarm signal is being output from the fire determination circuit; A signal for stopping the output operation of the alarm signal is output to the fire determination circuit for a preset time when activated by an output pulse signal, and a signal for stopping the operation of the one-shot circuit is sent to the one-shot circuit. A fire alarm, comprising a timer circuit for outputting. 2. The fire alarm device according to claim 1, wherein the one-shot circuit outputs a pulse signal when the ON state of the sound stop switch continues for a predetermined time.