JP2983719B2 - Smoke sensing device with alarm stop circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting smoke and issuing an alarm, and more particularly to a smoke detection device capable of temporarily stopping an alarm sound.

[0002]

2. Description of the Related Art Smoke sensing devices can erroneously emit an audible alarm when a fire is not occurring. For example, an alarm may be issued when kitchen smoke or cigarette smoke enters the sensor. In this case, it is convenient to forcibly suspend the loud alarm sound. However, after a certain period of time has passed and the smoke has been naturally discharged from the sensing unit, it is also important to make the operation unit stand by again. The simplest circuit for realizing this is to provide an alarm stop switch, stop the alarm sound when the alarm stop switch is operated, and set the alarm stop switch to an operating state with the alarm stop switch restored. However, according to this circuit configuration, it is necessary to manually operate the alarm stop switch both at the time of stopping the alarm and at the time of restoring the alarm, and there is a drawback that the handling is troublesome. In particular, there is a disadvantage that the smoke detection device does not operate if the alarm stop switch is forgotten to be restored.

[0003] In order to solve this drawback, a smoke sensing device has been developed in which the time during which the operation is interrupted is set by a timer (Japanese Utility Model Publication No. 58-44474). In this smoke detection device, an alarm stop switch is connected to a timer, and when a signal is input from the alarm stop switch, the timer starts counting. During the timer count, the alarm sound is not forcibly generated.

[0004]

The smoke detector of this structure is automatically returned to a state in which the smoke can be detected by the timer after the time when the smoke is naturally exhausted from the detector. Therefore, there is a feature that the operation of the alarm stop switch can be simplified and used conveniently. However, this smoke detection device has a drawback in that it is not possible to confirm that the timer has been set up and the smoke can be sensed, and it is not possible to know whether or not the smoke is being sensed. Also,
If the timer is accidentally set when the smoke detection circuit does not detect smoke, there is a disadvantage that smoke cannot be detected for a certain period of time.

The present invention has been developed to further solve the above-mentioned drawback, and an important object of the present invention is to provide a smoke detecting device in which a timer does not start counting when smoke is not detected. is there.

[0006]

According to the present invention, there is provided a smoke detecting device comprising:
In order to achieve the above object, the following configuration is provided. That is, the smoke detection device of the present invention includes the smoke detection circuit 1
An alarm sound generating means 2 which is controlled by an output of the smoke detection circuit 1 to emit an alarm sound; and a stop circuit 3 for temporarily stopping the alarm sound generating means 2 from generating an alarm sound. 3 includes a manual switch 4 and a timer 5, and the timer 5 starts counting by a signal from the manual switch 4,
This is an improvement of the one configured to forcibly interrupt the generation of the alarm by the alarm sound generating means 2 during the timer count.

[0007]

Further, in the smoke detecting device of the present invention, even if the manual switch 4 is operated in a state where smoke is not detected, the stop circuit 3 is provided with the smoke detecting circuit 1 so that the alarm sound generating means 2 does not stop operating. And the stop circuit 3 temporarily stops the operation of the alarm sound generation means 2 only when the manual switch 4 is operated in a state where the smoke detection circuit 1 outputs a smoke signal. ing.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiment is an example of an apparatus for embodying the technical idea of the present invention, and the apparatus of the present invention has the following structure by changing the material, shape, structure, and arrangement of the component parts. Not specified. The device of the present invention can be modified in various ways within the scope of the claims.

Further, in this specification, in order to facilitate understanding of the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “means for solving the problems”. Column). However, the members described in the claims are by no means specified as members of the embodiments.

The photoelectric smoke detecting device shown in FIGS. 1 and 2 comprises a smoke detecting circuit 1, an alarm sound generating means 2, and a stop circuit 3.
And

The smoke detecting circuit 1 includes a light emitting circuit 6, a light receiving circuit 7, an amplifying circuit 8, a comparing circuit 9, an oscillating circuit 10, a malfunction preventing circuit 11, and a power supply circuit 12.

The light emitting circuit 6 is connected to a light emitting diode LED ₁ for irradiating light toward a smoke sensing portion, and a transistor Q ₅ which blinks the light emitting diode LED _1.
When, and a transistor Q ₄ for on-off control the transistors Q _5. The light emitting diodes LED _1, is connected to current limiting resistor R ₅₂ in series.

The light receiving circuit 7 includes a light receiving element PD ₁ and a capacitor C ₁ connected in parallel with the light receiving element PD ₁ for removing noise. The light receiving circuit 7 is provided at a position for receiving scattered light of smoke.

Although not shown, the light receiving element PD ₁ is provided at a position where the light emitted from the light emitting diode LED _{1 is} not directly received. The light-receiving element PD ₁ is the light emitted from the light emitting diodes LED _1, is reflected by the smoke during a fire, it is disposed at a position for receiving the scattered light.

Although not shown, the light receiving element PD ₁
It is disposed in a dark box that receives light scattered by smoke emitted from the light emitting diode LED ₁ and does not receive external light. The dark box has a structure in which smoke can enter but outside light cannot enter.

As the light emitting diode LED ₁ and the light receiving element PD ₁ , all having the same structure as that used in a conventional smoke sensing device or the same as that used in a smoke sensing device to be developed later can be used.

The light receiving circuit 7, the light receiving element PD ₁ is the receiving scattered light from the smoke, to generate a "smoke present" signal the micro voltage.

The amplification circuit 8 amplifies the "smoke present" signal of the light receiving circuit 7. The amplifier circuit 8 shown in FIG. 2 includes an operational amplifier IC _1-1 connected to the input side and an operational amplifier IC
_1-2 . In the input-side operational amplifier IC _1-1 is operating amplifier, "smoke present" signal on the input side are inputted to the output side of the operational amplifier IC _1-2, "smoke present" signal is amplified and output. This "smoke present" signal is input to the comparison circuit 9 connected to the output side.

The comparison circuit 9 is an operational amplifier. A reference voltage is applied to the negative input terminal via voltage dividing resistors R ₁₄ and R ₁₃ . The input terminal on the plus side connects the output side of the amplifier circuit 8. When a signal having a voltage level equal to or higher than the reference voltage is input from the amplifier circuit 8, the comparison circuit 9 outputs a signal indicating “smoke present”.

The malfunction prevention circuit 11 operates at a fixed cycle with 2
An alarm signal is output when the "smoke present" signal is input consecutively. The malfunction prevention circuit 11 shown in FIG. 2 includes two D flip-flops IC _2-1 and IC _2-2 , an RC delay circuit,
And a NOR circuit IC _3-1 .

The flip-flop IC _2-1 on the input side has:
A “smoke present” signal is input from the comparison circuit 9. Therefore, the data terminal D of this flip-flop IC _2-1
Is connected to the output of the comparison circuit 9. The two flip-flops IC _2-1 and IC _2-2 operate as shift registers. Output terminal Q of input side flip-flop IC _2-1
Is output D flip-flop I through an RC delay circuit.
It is connected to the data terminal D of the C _2-2. The output terminals of the two flip-flops are connected to the input side of the NOR circuit. Both flip-flops IC _2-1, a clock terminal CK of the IC _2-2 is connected to the collector of the transistor Q _6, based transistor Q ₆ is connected to the light emitting diodes LED _1. Transistor Q ₆ is turned on by base current flows when lighting the light emitting diodes LED _1. Transistor Q ₆ when the light emitting diode LED ₁ is turned off is turned off, the clock pulse at this time is input to the flip-flop.

The malfunction preventing circuit 11 outputs a buzzer signal when the "smoke present" signal is input twice by the following operation. Initially, the data terminals D of both flip-flops IC _2-1 and IC _2-2 are at "L". From the comparison circuit 9, the input side D flip-flop IC
The "H" signal of "smoke present" is input to the data terminal D of _2-1 . A clock pulse is input to the clock terminals CK of both flip-flops IC _2-1 and IC _2-2 slightly after the "H" signal of "smoke present". When the clock pulse is input, the output terminal Q of the input-side D flip-flop IC _2-1 becomes “H”. This is because the data terminal D is "H" in the "smoke present" signal. However, the output of the output terminal Q of the output side D flip-flop IC _2-2 becomes “L”. That is, when a clock pulse is inputted to the clock terminal CK, the data terminal D becomes "
In this state, the output of the NOR circuit becomes “L” because the output of the output side flip-flop IC _2-2 is “H”.
Because it is. Then, after a certain time, when the input is "smoke present" to the input side flip-flop IC _2-1 from the comparison circuit 9 again, both of the flip-flop IC _2-1, IC _2-2 is "L"
The signal is input to the NOR circuit IC _3-1 . It is the "H" output signal of the input flip-flop IC _{2-1 and} the output of the output flip-flop IC _2-2 is set to the "H" state.
Also, this is because the input-side flip-flop IC _2-1 outputs “H” to the output terminal Q by the next “smoke present” signal. "L" of both flip-flops IC _2-1 and IC _2-2
The signal is input to the NOR circuit, and the NOR circuit outputs an “H” signal, that is, an alarm signal. The alarm signal is sent to the alarm sound generating means 2 to sound a buzzer.

By the way, when the "smoke present" signal is not input after the flip-flop IC on the output side,
_2-2 the output terminal Q of becomes a "H", the output terminal Q of the input side flip-flop IC _2-1 is a "L", NO
The R circuit outputs "L" and does not output an alarm signal. The malfunction prevention circuit 11 outputs an alarm signal when "smoke present" is input twice consecutively.

Although not shown, three flip-flops are connected, and the output of the data terminal D of each flip-flop is connected to A.
If the signal is input to the ND circuit, the storage circuit can output a buzzer signal when "smoke present" is input three times in succession.

The oscillation circuit 10 includes an operational amplifier IC _4-1 ,
C _4-2 , IC _4-3 and IC _4-4 are provided. Operational amplifier I
A resistor R ₃₅ connected to the output side of C _4-3 to specify the oscillation cycle
Connecting the transistor Q ₃ in parallel with. The transistor Q ₃ is connected to a flip-flop IC _2-1 ,
Connected to _2-2 output terminal. Transistor Q ₃
"H" from either flip-flop IC _2-1 or IC _2-2
There A resistor R ₃₄ is electrically connected to the input in parallel with the resistor R _35, shortening the period of the oscillation circuit 10.

The rectangular wave output from the oscillation circuit 10 is supplied to a power supply circuit 12. The power supply circuit 12 includes the oscillation circuit 10
The transistor Q ₇ is turned on and off controlled by the output of, and a power supply IC ₅ for stabilizing the output voltage of the battery.
The transistor Q ₇ supplies power to the light receiving circuit 7 and the comparing circuit 9. The power supply IC ₅ supplies the stabilized voltage to the light emitting circuit 6 and the malfunction prevention circuit 11, and outputs the output to the resistor R
_The voltage is divided by the capacitor ₄₆ and the capacitor C ₁₂ and supplied to the oscillation circuit 10. The alarm sound generating means 2 is directly connected to the battery.

The output of the oscillation circuit 10 is a phase inversion amplifier I
It is connected to the light emitting circuit 6 via _C4-5 . Emitting circuit 6, when IC _4-4 of the oscillation circuit 10 is "H", the lights of the light emitting diodes LED _1, turns off the light emitting diodes LED ₁ when the "L".

The alarm sound generating means 2 includes a piezoelectric buzzer DZ
₁ and a transistor Q for driving the piezoelectric buzzer DZ _1
8 and is provided. Based transistor Q ₈ is an inverter IC _3-3 connected in series, NOR circuit IC
_3-2 and is connected to the malfunction prevention circuit 11.
Alarm sound generating means 2 generates an alarm sound is supplied bias current to the piezoelectric buzzer DZ ₁ to input a signal of "L" on the side is input transistor Q ₈ of inverter IC _3-3.

The smoke detecting circuit 1 and the alarm sound generating means 2 having the above-described circuit structure operate as follows to detect smoke and issue an alarm. In synchronization with the oscillation period of the oscillation circuit 10, the light emitting diode LED ₁ is flashing at a constant period. When the light emitted from the light emitting diode LED ₁ is scattered by smoke, the light is received by the light receiving circuit 7. The light receiving circuit 7 outputs a “smoke present” signal, which is input to the malfunction prevention circuit 11. When a signal indicating "smoke present" is input to the malfunction preventing circuit 11 twice or more, the output of the NOR circuit IC _3-1 of the malfunction preventing circuit 11 becomes "H" and an alarm signal is output. "H" warning signal is in, "L" becomes the output side of the NOR circuit IC _3-2, further passes through the inverter IC _3-3 "H" next to the transistor Q ₈ of the warning sound generating means 2 Supply base current. When the base current is supplied to the transistor Q _8,
Transistor Q ₈ and the piezoelectric buzzer DZ ₁ is oscillating, emits a warning sound.

The smoke detector shown in FIGS. 1 and 2 includes a stop circuit 3 for forcibly interrupting the alarm from the alarm generating means 2. The stop circuit 3 includes a timer 5 and a manual switch 4. Timer 5
It is composed of a capacitor C ₁₄ connected in parallel with each other and a resistor R _32. Positive side of the capacitor C ₁₄ is connected to the battery power supply circuit 12 through a manual switch 4, it is charged when the manual switch 4 is pressed in the capacitor C _14. Capacitor C ₁₄ is, NOR circuit IC _3-2 via the Zener diode ZD ₁ and the diode D _3-2
Is connected to the input side.

Further, the output side of the Zener diode ZD _{1 and} the input side of the inverter IC _3-4 are connected to a capacitor C
To rapidly discharge the ₁₄ is connected to the output side of the NOR circuit IC _3-2 via the discharge resistor R ₅₁ and diode D _3-1. Further, the output side of the inverter IC _3-4 forcibly resets the "H" output of the malfunction prevention circuit 11 to "H".
In order to stop the alarm as L ", it is connected to the input side of the NOR circuit IC _3-2 via the diode D _3-2 .
Further, the output side of the inverter IC _3-4 has a timer 5
NO but in order to ringing momentarily transmit momentarily ringing signal to the moment the warning sound generating means 2 when setting up, via the coupling capacitor C ₁₅ and the diode D _2-1
Connected to another input side of R circuit IC _3-2 .

The stop circuit 3 having this circuit configuration performs the following operation, interrupts the sounding of the alarm for a certain period of time, and momentarily stops when the timer 5 is set up and returns to the state where the alarm sounds. Sound. In a state where the malfunction prevention circuit 11 is outputs "H", when the manual switch 4 is pressed, is charged in the capacitor C _14. When the potential of capacitor C ₁₄ becomes higher input side of the inverter IC _3-4 becomes "H". The output side of the inverter IC _3-4 becomes "L". "L" of inverter IC _3-4 is NOR circuit IC _3-2
Is supplied to the input side. In this state, “H” of the malfunction prevention circuit 11 is forcibly set to “L” by the stop circuit 3 to stop the alarm sound generation unit 2 from issuing an alarm. Over time, the voltage of the capacitor C ₁₄ is reduced gradually. It is because the charge of the capacitor C ₁₄ is equal to the resistance R
_{This is} because discharge is performed from ₃₂ . According capacitor C ₁₄ is discharged, the voltage at the input side of the inverter IC _3-4 is lowered, which falls below the threshold value of the inverter IC _3-4, the output side of the inverter IC _3-4 is the "H" Become. When the output of the inverter IC _3-4 is "L" to "H", the coupling capacitor C ₁₅ plus pulse is output to, the NOR circuit IC _3-2 This pulse signal via the diode D _2-1 A momentary "H" signal (momentary sound signal) is input. The instantaneous sounding signal which is the "H" signal causes the alarm sound generating means 2 to sound for an instant. When "H" on one side of the NOR circuit IC _3-2 is input, the output side of the NOR circuit IC _3-2 becomes "L", this "L" signal, capacitor C ₁₄ is connected through a resistor R ₅₁ Discharges rapidly.

In this state, the malfunction prevention circuit 11
When "H" is output, the alarm sound generating means 2 is in a state of issuing an alarm.

The stop circuit 3 of this circuit configuration, when the output of the inverter IC _3-4 is "H" to "L", capacitor C ₁₄ through the diode D _3-1 and a discharge resistor R ₅₁
Is forcibly discharged. For this reason, when the timer 5 is set up, it sounds for a moment to notify that the smoke has been detected.

[0036] can not be forcibly discharged the capacitor C ₁₄ circuit, voltage of the capacitor C ₁₄ is reduced very slowly. It time constant is very large capacitor C ₁₄ and resistor R _32, that is why the set time of the timer 5 is significantly longer a few minutes to several well. In this circuit, the discharge of the capacitor C ₁₄ progresses,
When the threshold value of C _3-4 is approached, the output becomes “H” and “H”.
"Repeated and. In this state, the coupling capacitor C ₁₅ is," L L "to" is output momentarily ringing signal each becomes H "," Pyi from the alarm sound generating means 2, Pyi, Pyi &・ ・ ”, Etc. Therefore, there is a disadvantage that the alarm sound generating means 2 sounds intermittently and this state continues.

In the circuit shown in FIG.
When ringing times, since the forcibly discharge the capacitor C _14, it is not a situation of this kind develops.

Further, the circuit shown in FIG.
Is producing an output signal of "H".
The warning sound is stopped for a certain period of time only when the warning is issued by detecting smoke. That is, even if the manual switch 4 is operated while the smoke detection circuit 1 does not detect smoke, the timer 5 does not start counting. For this reason, even if the manual switch 4 is operated in a state where smoke is not detected, the timer 5 does not start counting.
If smoke is detected immediately thereafter, an alarm can be issued.

[0039] To achieve this, it connects the transistor Q ₉ in parallel with the capacitor C _14. The transistor Q ₉ has a collector connected to the positive side of the capacitor C ₁₄ , an emitter connected to the ground, and a base connected to the output of the malfunction prevention circuit 11 via the inverter IC ₆ . Transistor Q ₉ is turned on in the state of the output is "L" of the lockout circuit 11 to short both ends of the capacitor C ₁₄ at this time.

That is, the smoke detection circuit 1 does not detect smoke,
When the malfunction prevention circuit 11 outputs “L”, the output of the inverter IC ₆ becomes “H”, and a base current flows to the transistor Q ₉ to be turned on. When the smoke detection circuit 1 detects smoke, the malfunction prevention circuit 11
H ”, the output of inverter IC ₆ is“
L ", the transistor Q ₉ is turned off. Therefore, transistor Q ₉ is, in a state where no sensing smoke by shorting both ends of the capacitor C _14, in the state that senses smoke short circuits both ends of the capacitor C ₁₄ Instead, the electric charge is charged from the manual switch 4 and the timer 5 is operated.

FIG. 3 shows a time chart in this state. Figure 3 shows the output point of the smoke detector circuit 1 a, the output point of the inverter IC ₆ b, the voltage variation on the positive side point c of the capacitor C _14. As shown in this figure, when the smoke detection circuit 1 does not detect smoke, that is, when the output of the smoke detection circuit 1 is "L", the manual switch 4 is operated.
The potential at point c does not change, and the timer does not start counting. However, if the manual switch 4 is turned on when the smoke detection circuit 1 detects smoke and outputs "H", c
The voltage at the point increases, the timer starts counting, and the alarm sound generation means temporarily stops issuing an alarm.

[0042]

According to the smoke detecting device of the present invention, the stop circuit is equipped with a timer for temporarily stopping the alarm sound. The timer starts counting when a manual switch is operated, and forcibly stops the alarm sound during counting. When the timer is set up, the alarm sound generation means waits for the smoke to be sensed again and emits an alarm.

Further, in the smoke detection device of the present invention, the stop circuit is connected to the smoke detection circuit, and the stop circuit does not start counting the timer even if the manual switch is operated in a state where the smoke is not detected. I have. For this reason, even if the manual switch is operated by mistake when the alarm is not generated, the smoke detection state is not limited. The stop circuit starts counting the timer only when the manual switch is operated when it is necessary to stop the alarm by detecting smoke,
Stop the alarm for a certain period of time. Therefore, even if the manual switch is operated when there is no need to stop the alarm, the detection of smoke is not interrupted.

[Brief description of the drawings]

FIG. 1 is a block diagram of a smoke sensing device showing one embodiment of the present invention.

FIG. 2 is a circuit diagram of the smoke sensing device shown in FIG. 1;

FIG. 3 is a graph showing a voltage change at each point of the smoke sensing device shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Smoke detection circuit 2 ... Alarm sound generation means 3 ... Stop circuit 4
... Manual switch 5 ... Timer 6 ... Light emitting circuit 7 ... Light receiving circuit 8 ... Amplifying circuit 9 ... Comparison circuit 10 ... Oscillation circuit 11 ... Malfunction prevention circuit 1
2. Power supply circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-176196 (JP, A) JP-A-58-205295 (JP, A) Fully open 1979-57063 (JP, U) Really open 66483 (JP, U) Fully open 1986-196393 (JP, U) Fully open 1986-46689 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G08B 17/00-31 / 00

Claims (1)

(57) [Claims] A smoke detection circuit (1), an alarm sound generation means (2) controlled by an output of the smoke detection circuit (1) to generate an alarm sound, and an alarm sound generation means (2) generates an alarm sound. A stop circuit (3) for temporarily suspending the operation of the manual switch (4), the stop circuit (3) including a manual switch (4) and a timer (5).
The timer (5) starts counting by a signal from the device, and the alarm sound generation means (2) forcibly stops generating an alarm during the timer counting. 3) is connected to the smoke detection circuit (1), and the stop circuit (3) is operated only when the manual switch (4) is operated with the smoke detection circuit (1) outputting a smoke signal. A smoke detection device having an alarm stop circuit, wherein the operation of the alarm sound generation means (2) is temporarily stopped.