JPH05325065A - Photoelectric smoke sensor - Google Patents

Abstract

PURPOSE:To easily and accurately adjust the sensitivity, to prevent the malfunction of a storage circuit, and to fix the current consumption of a constant voltage circuit. CONSTITUTION:This sensor is provided with an amplifying circuit which has a variable resistance VR1 for output adjustment and amplifies the light reception output of a smoke detecting photodetector PD, a fire discriminating part 30 which is provided with a variable resistance VR2 for reference voltage adjustment and a transistor TR Q7 for fire discrimination, a storage circuit 40 which discriminates whether the TR Q7 is turned on continuously plural times synchronously with the pulse output of an oscillating circuit or not, and a constant voltage circuit 60 where a TR Q9 is provided with a constant current circuit 62 between its own collector and base and a Zener diode Z1 is connected between the base of the TR Q9 and an earth terminal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric smoke detector.

[0002]

2. Description of the Related Art In a conventional photoelectric smoke detector, when smoke is generated due to a fire, light emitted from a smoke detecting light emitting element in a light emitting section becomes scattered light due to the smoke and is received by a light receiving section for smoke detection. Enter the element. The scattered light that has entered the light receiving element is amplified through an amplifier circuit and then output to a fire determination unit, and fire determination is performed based on the output value. When it is determined that there is a fire, the determining unit sends a fire signal to the fire signal sending unit via the storage circuit, and thus the sending unit sends the fire signal to a fire receiver or the like to notify the fire.

In the conventional photoelectric smoke detector, the sensitivity of the detector is adjusted by the sensitivity adjusting means and the operation of the fire discriminating unit and the like is stabilized by the constant voltage circuit. Further, in the sensor, the pulse output of the oscillation circuit is supplied to the operation indicator lamp and the indicator lamp is blinked and turned on to confirm whether or not the sensor is operating normally.

[0004]

The photoelectric smoke detector of the conventional example has the following problems. (1) In the sensitivity adjustment of the conventional example, a reflector for generating scattered light equivalent to scattered light generated when smoke of 10% / m enters, for example, is placed in a dark box for smoke detection of a photoelectric smoke detector, and at that time. The reference resistance of the comparator is selected so that the fire discrimination circuit, for example, the comparator operates with the detection output of the comparator.

However, in such a method, the detection output is different depending on the variation of the circuit constant of the electric circuit in each photoelectric smoke sensor, so that the sensitivity adjustment, that is, the selection of the reference resistor is troublesome. Also, because the photoelectric smoke detectors have different detection outputs, the sensitivity of the detectors is different, so trying to know how the sensitivity of the sensor is changing from the initial state, the initial detection output of each sensor It is troublesome to know.

(2) The conventional storage circuit is composed of a plurality of D-type flip-flops. However, in this storage circuit, there is a case where the fire signal transmission section erroneously transmits a fire signal by operating when the power is turned on, for example, when a fire recovery operation is performed.

(3) The conventional constant voltage circuit comprises a transistor, a Zener diode connected to the base of the transistor, and a resistor connected between the collector and the base of the transistor. ..

However, in this constant voltage circuit, when there is a large difference in the power supply voltage supplied to the smoke detector for each fire receiver, the fire receiver to be connected consumes the constant voltage circuit of the smoke detector. The currents are very different. For example, when the power supply voltage is high, the current flowing through the Zener diode of the constant voltage circuit is large, and when the power supply voltage is low, the current flowing through the Zener diode of the constant voltage circuit is small.

Therefore, in the case of a fire receiver with a high power supply voltage supplied to the smoke detector, the number of smoke detectors that can be connected is smaller than that of a fire receiver with a low power supply voltage, compared with the current consumption of the constant voltage circuit. There is a drawback that it is severely restricted due to the problem. In addition, the power supply voltage of the fire receiver may be unstable and fluctuate. In this case, if the fire detector is changed to a smoke detector having a semiconductor circuit, the required number of fire detectors cannot be connected.

(4) The oscillation circuit of the conventional operation indicator lamp is
It is provided separately from the pulse oscillating circuit for supplying the pulse output for light emission to the smoke detecting light emitting element of the light emitting section. Therefore, even if the pulse detection circuit for smoke detection fails and the light emitting element does not emit light, that is, even if fire monitoring cannot be performed, the indicator lamp blinks and lights if the oscillator circuit is normal. However, it shows that the sensor is normal.

In view of the above circumstances, an object of the present invention is to perform sensitivity adjustment easily and accurately and prevent the storage circuit from malfunctioning. Another object is to make the current consumption of the constant voltage circuit constant and to surely turn off the operation indicator lamp when the fire detector fails and smoke cannot be detected.

According to the present invention, there is provided a smoke detecting light emitting element, and a light emitting section having an oscillating circuit for supplying a pulse output to the light emitting element; the light emitted from the smoke detecting light emitting element is not directly received, A smoke detection light receiving element for receiving scattered light of the emitted light, a first stage amplifier circuit having an output adjusting variable resistor for amplifying the light reception output of the light receiving element, and the first stage output A light-receiving portion having a second-stage amplifier circuit for further amplifying; a dividing resistor circuit having a reference voltage adjusting variable resistor to which the received light amplified output of the light-receiving portion is supplied; A fire discriminating unit having a transistor for discriminating fire which is turned off; the output of the transistor of the fire discriminating unit is connected to the output of the oscillation circuit of the light emitting unit, and the pulse output of the oscillation circuit is synchronized. Then the above A storage circuit that determines whether or not the transistor of the disaster determination unit has been continuously turned on a plurality of times, and generates a detection output when it is determined that the transistor has been turned on a plurality of times continuously; A switching element for transmitting a fire signal, and a fire signal transmitting portion provided with an operation indicator lamp connected in series with the switching element; a power source for the light emitting portion, the light receiving portion, the fire discriminating portion, and the storage circuit. A constant voltage circuit for supplying a constant current circuit between the collector and the base, and a constant voltage circuit in which a Zener diode is connected between the base and the ground terminal of the transistor. A photoelectric smoke detector characterized by the above is intended to achieve the above object.

[0013]

When the oscillation circuit of the light emitting section outputs a pulse to the smoke detecting light emitting element, the light emitting element emits pulsed light toward the smoke detecting light receiving element of the light receiving section. Further, the pulse output is supplied to the operation indicator lamp after the pulse width is expanded through the pulse width expansion circuit. As a result, the operation indicator lamp blinks and lights.

When smoke enters the dark box of the detector due to the occurrence of fire, scattered light enters the smoke detecting light receiving element of the light receiving portion, and the scattered light becomes a light receiving output and enters the first stage amplifier circuit, Therefore, after being amplified, it is further amplified by the second stage amplifier circuit,
Received light amplification output. When this amplified output is supplied to the fire discrimination unit, the fire discrimination transistor is turned on and output to the storage circuit.

In this storage circuit, it is judged whether or not the transistor of the fire judging section is continuously turned on a plurality of times in synchronization with the pulse output of the oscillation circuit, and it is judged that the transistor is continuously turned on. When it does, the detection output is sent to the fire signal sending unit. In the fire signal transmitting section, the switching element for transmitting the fire signal is turned on by the detection output, and the fire signal is transmitted to the fire receiver. At this time, the operation indicator light changes from blinking lighting to continuous lighting.

When the sensitivity is adjusted, the variable resistor for output adjustment is adjusted so that the received light amplified output when there is no smoke in the dark box becomes a predetermined value. The received light amplified output at this time is used for smoke detection. This is an output that receives scattered light generated on the inner wall of the dark box when the light emitting element emits light.

Next, a reflecting plate that causes light reflection equivalent to smoke having a predetermined concentration is placed in the dark box, and the variable resistor for adjusting the reference voltage is adjusted so that the fire determining transistor of the fire determining unit is turned on.

The power supplied from the fire receiver to the detector enters the constant voltage circuit and is subjected to the constant current action of the constant current circuit, so that the current flowing through the Zener diode is always kept constant.

[0019]

Embodiments of the present invention will be described with reference to the accompanying drawings. The light emitting unit 10 includes a smoke detecting light emitting element L1, transistors Q13 to Q15, resistors R27 to R33, and a capacitor C.
12 to C15. In the light emitting unit 10, the transistors Q13 and Q15 and the resistors R27 and R2 are included.
8, R30 to R33 and capacitors C12, C14, C1
An oscillation circuit is composed of 5 and 5. This oscillation circuit supplies a pulse output to the light emitting element L1.

The pulse width expansion circuit 12 is constituted by the transistor Q14, the resistor R29, the capacitor C13 and the diode D2. The circuit 12 expands the pulse width of the pulse output of the oscillation circuit and supplies it to the operation indicator lamp L2 of the fire signal transmitting section 50.

The light receiving section 20 includes a smoke detecting light receiving element PD, transistors Q1 to Q4, resistors R1 to R4, an output adjusting variable resistor VR1, and capacitors C2 to C5 and C18. The light receiving element PD does not directly receive the light emitted from the light emitting element L1, but receives the scattered light of the emitted light.

Transistors Q1 and Q2 and resistors R1 to R6
And output adjusting variable resistor VR1 and capacitors C2 and C18
And constitute a first-stage amplifier circuit. This amplifier circuit amplifies the light receiving output of the light receiving element PD, and the variable resistor VR1 is a first sensitivity adjusting variable resistor which is a feedback resistor of the amplifier circuit.

Transistors Q3 and Q4 and resistors R8 to R1
4 and the capacitors C3 to C5 form a second-stage amplifier circuit. This amplifier circuit further amplifies the output of the first-stage amplifier circuit.

The fire discrimination unit 30 includes a transistor Q7, resistors R18 to R20, a reference voltage adjusting variable resistor VR2, and a capacitor C8. The variable resistance VR2, the second fixed resistance R18, and the first fixed resistance R19 form a divided resistance circuit (series resistance circuit).

The variable resistor VR2 is a second variable resistor for sensitivity adjustment to which the received light amplified output of the light receiving unit 20 is supplied. The transistor Q7 has a base and an emitter connected to both ends of the second fixed resistor, and is a fire discrimination transistor that is turned on and off by the divided voltage of the divided resistor circuit.

The storage circuit 40 includes a transistor Q16, a resistor R36, a current limiting resistor R37, a resistor R38, a capacitor C17, and D-type flip-flops IC1 and IC2. The output of the transistor Q7 of the fire discriminating unit 30 and the output of the oscillation circuit of the light emitting unit 10 are connected to the circuit 40.

The storage circuit 40 synchronizes with the pulse output of the oscillator circuit, and the transistor Q7 of the fire discriminating section 30.
Is turned on a plurality of times in succession, and when it is turned on, a detection output is generated. In addition, VD
D is the + power supply terminal of D-FFIC1 and D-FFIC2,
Further, VSS is connected to each of the-power supply terminals.

The fire signal transmitting section 50 includes a silicon controlled rectifying element Q11, a transistor Q12, an operation indicator lamp L2, a Zener diode Z2, and resistors R23 to R26. The rectifying element Q11 is turned on by the detection output of the storage circuit 40, and the rectifying element Q11 is operated by the operation indicator lamp L2.
Are connected in series.

The transistor Q12 is turned on when the voltage detection circuits Z2 and R26 for detecting that the voltage applied to the operation indicator light L2 has become equal to or higher than the predetermined voltage, and is turned on when the voltage is applied to the operation indicator light L2 or higher. Is to prevent the application of the voltage.

The constant voltage circuit 60 comprises a transistor Q9, a junction field effect transistor Q10, a resistor R22 and a zener diode Z1. The constant voltage circuit 60 supplies power to the light emitting unit 10, the light receiving unit 20, the fire determination unit 30, and the storage circuit 40.

The transistor Q9 includes a constant current circuit 62 between the collector and the base, and the Zener diode Z1 is connected between the base of the transistor Q9 and the ground terminal. The constant current circuit 62 includes a junction field effect transistor (FET) Q10 having a drain connected to the collector of the transistor Q9 and a gate connected to the base of the transistor Q9, and the transistor Q1.
And a resistor connected between the source and gate of 0.

The sensor output circuit 70 includes a transistor Q6.
And resistors R15 and R16. Transistor Q
The base of 6 is connected to a connection point P between the output end of the light emitting section 10 and the divided resistance circuit of the fire discrimination section 30, and the emitter thereof is grounded via the output resistance R16.

The test circuit 80 comprises a transistor Q5, a capacitor C6, a diode D1 and a reed switch RS which is closed by the approach of a magnet. The switching element Q5 is provided in parallel with the reed switch RS and is turned on by a test signal from the outside of the sensor.

Reed switch RS and switching element Q
The parallel circuit with 5 is provided in parallel with the gain control resistor R10 of the second stage amplifier circuit of the light receiving section 20.

DB is a diode bridge circuit for depolarizing. Terminals 1, 2 and 3 are terminals for connecting a pair of power source / signal lines (not shown) for wiring, and the terminals 2, 3 are short-circuited inside the sensor so as to connect one power source / signal line.

The terminal 4 is an input terminal for a test signal (test voltage), and the terminals 5 and 6 are terminals for outputting an analog light receiving output of the light receiving section 20. 1 and 2 show the connection terminal a.
A single circuit is configured as a whole by to e.

The operation of this embodiment will be described. For example, if power is turned on to the detector due to fire recovery, D-
The capacitor C17 that supplies operating power to the FFIC1 and D-FFIC2 is τ =
Charged with a time constant of R37 x C17 and D-FFI
The voltage across the capacitor C17 is applied to C1 and D-FFIC2.

By the way, D-FFIC1 D-FFIC
2 is unstable when the power is turned on, and DF
There is a case where L output is generated from the output terminal Q2 of the FIC2 to the fire signal transmitting unit 50, that is, there is no output signal, and a case where H output is generated, that is, there is an output signal.

When the output terminal Q2 of the D-FFIC2 is L output, the capacitor C17 is charged as it is to a predetermined voltage. When the output terminal Q2 of the D-FFIC2 is the H output, the output terminal Q2 produces the H output whose current value is limited by the current limiting resistor R37.

On the other hand, the capacitor C17 is a current limiting resistor R
Electric charges are charged up to a voltage determined by the division ratio of 37 and resistors 23, R24, and R25. Therefore, since the current required for turning off the device Q11 is not supplied from the D-FFIC 2 to the gate of the silicon controlled rectifying device 11, the device 11 does not turn on.

The capacitor C12 of the light emitting portion 10 is charged through the resistor R27 by a power source supplied from a fire receiver, a repeater or the like (not shown) through the terminals 1 and 2 (3). When the charging voltage reaches the sum of the divided voltage of the resistors R32 and R33 and the base-emitter voltage V _BE of the transistor Q15 (hereinafter referred to as light emission reference voltage), the transistor Q15 turns on and the transistor Q13.
Also turn on.

When the transistor Q13 is turned on, the electric charge of the capacitor C12 is discharged through the resistor R28 and the smoke detecting light emitting element L1, the light emitting element L1 emits light, and the transistor Q14 is also turned on. At the same time, the discharge current charges the capacitor C13.

When the transistor Q15 is turned on, the transistor Q16 of the storage circuit 40 is turned on, and the clock signal is input to the D-FFIC1 and D-FFIC2 as the light emission synchronization signal. While the transistor Q13 is on, the capacitor C15 is charged by the base current of the transistor Q15, and the charge voltage turns off the transistor Q15.
Selected to emit light for 00 μs.

The transistor Q14 is the transistor Q1.
3 is turned on by the discharge current of the capacitor C12, and when the transistor Q13 is turned off, the capacitor C13 stops charging, and the capacitor C13 charges the electric charges charged up to that point in parallel. Discharge through the resistance of Q14, and the discharge current maintains the ON state.

Then, the transistor Q14 in the ON state
Supplies the electric charge of the capacitor C12 to the operation indicator lamp L2 of the fire signal transmitting section 50 as an operation power source. In this embodiment, the on-time of the transistor Q14 is selected to be 1 ms, for example, which allows humans to visually recognize that the operation indicator lamp L2 is lit.

The light receiving section 20 receives the scattered light due to the light emission of the smoke detecting light emitting element L1 by the smoke detecting light receiving element PD, amplifies the received light output by the two-stage amplifier circuit, and the fire discrimination section 3
Output to 0. The transistor Q7 of the fire discrimination unit 30 is
Amplified received light output is resistor R19, reference voltage adjustment variable resistor V
When the base voltage divided by R2 and the resistor R18 is lower than the base-emitter voltage, it remains off, and outputs a high (H) signal to the storage circuit 40. When it becomes higher than the base-emitter voltage, it turns on. A low (L) signal is output to the storage circuit 40 as a fire determination signal.

The D-FFIC1 of the storage circuit 40 has an output terminal if the H signal is input to the input terminal D1 when the clock signal (the synchronizing signal from the light emitting section 10) is input from the transistor Q16 to the clock terminal CL1. An H signal is produced from Q1, and an L output is produced from the inverting output terminal Q1. That is,
The storage circuit 40 is reset. As a result, D-FFIC
Since the output signal is not output from the second output terminal Q2, the capacitor C17 is restarted to be charged through the current limiting resistor R37 and charged to a predetermined voltage.

When the clock signal is input to the clock terminal CL2, the D-FFIC2 outputs the output terminal Q of the D-FFIC1.
With the L output of 1, the L output is output from the output end Q2 to the fire signal transmitting unit 50. Therefore, the silicon controlled rectifying element Q11 of the sending unit 50 maintains the off state.

The D-FFIC1 of the storage circuit 40 has an input terminal D when the clock signal is input to the clock terminal CL1.
When the L signal which is the fire discrimination signal is input to 1, an L output is generated from the output terminal Q1 and an H output is generated from the inverting output terminal Q1. On the other hand, the D-FFIC2 has a clock terminal CL.
When the clock signal is input to 2, the inverting output terminal Q2 of the D-FFIC1 is still the L output, so the output terminal Q2 maintains the L output.

In this state, when the clock signal is input to the clock terminal CL1 of the D-FFIC 1 and the L signal which is the fire discrimination signal is input again to the input end D1, D-
FFIC2 is the inverting output terminal of D-FFIC1 and H of Q1.
The output causes an H output from the output terminal Q2.

The electric charge charged in the capacitor C17 is discharged as an output signal by the H output of the D-FF1C2, and the fire signal transmitting section 5 is generated by the output signal of this discharge current.
The silicon controlled rectifier Q11 of 0 turns on, and terminals 1 and 2
Fire signal is sent from (3). As a result, the operation indicator light L2 is switched from the intermittent lighting by the pulse output of the light emitting unit 10 until then to the continuous lighting by the fire signal.

During transmission of this fire signal, the power supply voltage supplied from the receiver or the like fluctuates and rises, and the current flowing through the series circuit of the resistor R25 and the operation indicator lamp L2 increases, and the voltage of this series circuit increases. When the drop exceeds the Zener voltage of Zener diode Z2, Zener diode Z2 becomes conductive and transistor Q12 turns on. As a result, the operation indicator light L2
It is prevented that the current flowing through the circuit increases unnecessarily due to the fluctuation of the power supply voltage.

When a clock signal is input to the clock terminal CL1 of the D-FFIC1, the input terminal D1 changes from the L signal to the H signal.
When the signal changes, that is, when the fire determination unit 30 does not generate the determination output, the output terminal Q1 of the D-FFIC1 changes from the L output to the H output, and the inverting output terminal Q1 changes from the H output to the L output. Change to output.

The output terminal Q1 of the D-FFIC1 is L
The output changes to the H output, the D-FFIC 2 is reset, and its output terminal Q2 maintains the L output. Therefore, if the fire determination unit 30 outputs the determination signal only once due to some transient phenomenon, the storage circuit 40 does not generate an output, and the transmission unit 50 does not transmit the fire signal.

When the power supply from the receiver or the like is temporarily cut off to restore the operated fire detector, the silicon controlled rectifying element Q11 is restored and the storage circuit 4
The D-FFIC1 and D-FFIC2 of 0 are also set to the initial state.

When testing whether or not the fire detector operates, a test signal is applied to the terminal 4 from, for example, a receiver (not shown) to turn on the transistor Q5 of the test circuit 80.
Alternatively, a magnet (not shown) is brought close to the sensor to turn on the reed switch RS. As a result, the light receiving unit 20
The resistor R11 is connected in parallel to the resistor R10 of the amplifier circuit of the second stage, and the gain of the amplifier circuit of the second stage is increased. Then,
The light reception amplification output of the light receiving element PD by the light emission of the light emitting element L1 when there is no smoke becomes the output necessary for operating the transistor Q7 of the fire discrimination unit 30.

If there is no abnormality in the light emitting element L1, the light receiving element PD, the amplifying circuit, etc., the fire discriminating section 30 produces a fire discriminating output, and if the fire discriminating outputs are continuously generated, the accumulating circuit 40.
The fire signal transmission circuit 50 operates to transmit a fire signal, and the operation indicator lamp L2 is switched to continuous lighting.
Further, if any of these parts or circuits is abnormal, the sending circuit 50 does not send a fire signal, and the operation indicator lamp L2 does not continuously light.

To adjust the sensitivity of the photoelectric smoke detector, first, connect a tester such as a voltmeter to the terminals 5 and 6 so that the received light amplification output is a predetermined value when there is no smoke in the dark box of the detector (not shown). The variable resistor VR1 for output adjustment is adjusted so that The received light amplification output at this time is an output that receives scattered light generated on the inner wall of the dark box when the light emitting element L1 is generated.

Next, smoke having a predetermined density, for example, smoke having a density of 10% / m, or a reflector that causes light reflection equivalent to this is put in the dark box, and at this time, the transistor Q
The variable resistor VR2 for adjusting the reference voltage is adjusted so that 7 turns on.

When the variable resistor VR2 is adjusted, the smoke concentration or the reflection plate to be put in the dark box need not be the smoke concentration determined to be a fire or a reflection plate equivalent thereto. That is, each sensor adjusts each variable resistor VR1 to adjust the received light amplified output output from the amplifier circuit to a predetermined value. As a result, variations in the received light amplification output due to variations in the circuit components such as the light emitting element L1, the light receiving element PD, and the amplifier circuit between the sensors are corrected.

The received light amplification output is proportional to the smoke concentration flowing between the light emitting element L1 and the light receiving element PD. Therefore, the resistance R18 of the fire determination unit 30 may have a voltage drop corresponding to this arbitrary smoke density when the smoke density or a reflection plate that generates reflected light equivalent thereto is generated.

Therefore, when the discrimination level is adjusted by the reference voltage adjusting variable resistor VR2, the smoke concentration in the dark box or the reflection amount of the reflection plate equivalent thereto may be an arbitrary smoke concentration. The reference voltage adjusting variable resistor VR2 is adjusted so that the voltage drop generated in the series resistance circuit of the resistor R18 and the resistor R19 becomes the voltage drop corresponding to this arbitrary smoke density. As a result, when smoke having a predetermined concentration determined to be a fire flows into the dark box, a voltage drop required to turn on the transistor Q7 occurs in the resistor R18 of the fire determination unit 30 due to the received light amplification output at that time. ..

The smoke detecting light emitting element L1 of the light receiving unit 10 outputs, that is, the amount of light emission decreases when the temperature rises, but the transistor Q6 of the sensor output circuit 70 raises the base-emitter voltage V _BE when the temperature rises. descend. Therefore, the transistor Q6 compensates for the decrease in the output of the light emitting element L1. Further, the transistor Q6 expands the sensor output using the base-emitter voltage V _BE and outputs it to the test circuit 80. As a result, even a slight change in the sensor output is enlarged and output to the output terminals 5 and 6, so that the output adjusting variable resistor VR1 and the reference voltage adjusting variable resistor VR2 are output.
This makes it easy to adjust sensitivity and check sensitivity changes.

The constant voltage circuit 60 includes an FET Q10 and a resistor R.
By the constant current action of the constant current circuit 62 composed of 22, the current flowing through the Zener diode Z1 is kept constant and the current consumption in the constant voltage circuit 60 is kept constant. Therefore, even if the power supply voltage changes, the current consumption of the constant voltage circuit 60 does not change.

The storage circuit 40 has a D-FF when the power is turned on.
In order to prevent the IC1 and the D-FFIC2 from malfunctioning and operating the fire signal transmission circuit 50, a series circuit of the current limiting resistor R37 and the capacitor C17 is provided. This capacitor C17 is composed of D-FFIC1 and DF
It has a role of supplying power to the FIC2, and limits the current supplied to the D-FFIC1 and D-FFIC2 by the current limiting resistor R37 until the charging voltage is charged to a predetermined voltage.

As a result, immediately after the power is turned on, the D-FFI
The state of C1 and D-FFIC2 is unstable, and D-FFIC
2 produces H output from the output terminal Q2, D-FFIC2
Prevents the silicon control rectifier Q11 from obtaining the current necessary for triggering (operating).

Then, a clock pulse (synchronization signal) is input from the light emitting section 10, and the output terminal Q of the D-FFIC 2 is at L level.
When set to the output, the capacitor C17 is charged up. This prevents a malfunction when the power is turned on.

The above embodiment relates to a normal fire detector which sends out a fire signal when the light receiving section 20, that is, the fire phenomenon detecting section detects a fire phenomenon such as smoke judged to be a fire. In the case of an analog fire detector that sends a signal corresponding to the physical quantity of the fire phenomenon detected by the detector, it is configured as follows.

That is, instead of the fire discrimination unit 30, A
/ D (analog / digital) converter and a converter for converting a digital signal read from the converter into a form suitable for signal transmission and outputting the converted signal, for example, a parallel / serial converter, an A / D converter or a parallel series A signal processing circuit including a control circuit for controlling the operation of the converter and the like is provided.

Further, instead of the fire signal transmitting section 50,
A signal transmission unit having a transistor or the like that is turned on / off by a serial code signal output from the parallel-serial converter is provided. Then, the constant voltage circuit supplies a constant voltage to the fire phenomenon detection unit and the signal processing circuit.

In the above-mentioned embodiment, the storage circuit 40 in which the two-stage type, that is, two D-type flip-flops D-FFIC1 and D-FFIC2 are cascade-connected has been described. This storage circuit 40 is as shown in FIG. Three-stage type, that is, three D-type flip-flops D-FFCH1, D-FFIC2, D
-The FFIC 3 may be formed by continuous connection.

In the two-stage type storage circuit of the above embodiment, the storage circuit 40 operates to generate an output signal when the fire discrimination section 30 produces the fire discrimination output twice in succession, whereas the three-stage type storage circuit. In the storage circuit, the output signal is generated by the storage circuit when the fire determination unit 30 generates the fire determination output three times in a row.

In the above embodiment, the fire discriminating unit 30 discriminates the fire by the transistor Q7, but the comparator may discriminate the fire. In this case, the output of the light receiving unit 20 is connected to one input end of the comparator,
A reference voltage output point of a reference voltage generating circuit including a first fixed resistor, a second fixed resistor, and a variable resistor for adjusting a reference voltage is connected to the other input terminal, and the reference voltage output point is used as a reference. The terminal for voltage measurement may be connected.

[0074]

Since the present invention is configured as described above, it has the following remarkable effects. (1) A first-stage amplifier circuit having an output adjusting variable resistor for amplifying the light receiving output of the light emitting element, and a fire discriminating unit having a reference voltage adjusting variable resistor to which the light receiving amplified output of the light receiving unit is supplied. Since the and are provided, it is possible to adjust the amplified output to a predetermined output value by the output adjustment variable resistor and to adjust the switching level of the fire determination unit to the predetermined value by the reference voltage adjustment variable resistor.

Therefore, the amplified output of the amplifier circuit of each photoelectric smoke detector can be made the same value, and the switching level of the fire discrimination section of each photoelectric smoke detector can be made the same value. The sensitivity adjustment of the photoelectric smoke detector becomes easy.

Further, since the received light amplification output of the amplification circuit of each photoelectric smoke detector has the same value, it is possible to easily know how much the detection output of the detector in the smoke-free state changes from the initial detection output. be able to.

(2) It is determined whether or not the transistor of the fire discriminating section is continuously turned on a plurality of times in synchronism with the pulse output of the light emitting section, and it is detected when it is discriminated that the transistor is turned on a plurality of consecutive times. Since the storage circuit that sends the output to the fire signal sending unit is provided, the fire signal sending unit does not malfunction when the power is turned on.

(3) Since the transistor having the constant current circuit between the collector and the base and the constant voltage circuit in which the Zener diode is connected between the base of the transistor and the ground terminal are provided, the collector of the transistor of the constant voltage circuit is provided. Even if the power supply voltage from the fire receiver applied between the zener diode and the cathode of the zener diode is different, the current flowing through the zener diode is always a constant current due to the action of the constant current circuit provided in series with the zener diode. .. Therefore, the current consumption of the constant voltage circuit becomes constant regardless of the level of the power supply voltage.

(4) The light emitting portion is provided with a pulse width expanding circuit for expanding and outputting the pulse width of the pulse output of the oscillation circuit, and the output of the pulse width expanding circuit is the operation indicator lamp of the fire signal sending portion. Since the pulse output of the oscillation circuit for controlling light emission of the smoke detection light emitting element is expanded by the pulse width expansion circuit, the expansion pulse lights the operation indicator lamp. Therefore, when the oscillating circuit stops oscillating in the indicator lamp and smoke detection cannot be performed, the indicator lamp also stops blinking, and it can be known that an abnormality has occurred in the sensor.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention and a diagram showing an upper half thereof.

FIG. 2 is an electric circuit diagram showing an embodiment of the present invention and is a diagram showing a lower half thereof.

FIG. 3 is an electric circuit diagram showing another embodiment of the present invention.

[Explanation of symbols]

 10 Light Emitting Section 12 Pulse Width Expansion Circuit 20 Receiving Section 30 Fire Discriminating Section 40 Storage Circuit 50 Fire Signal Sending Section 60 Constant Voltage Circuit 62 Constant Current Circuit 70 Sensor Output Circuit 80 Test Circuit

Claims (16)

[Claims] 1. A light emitting section comprising a smoke detecting light emitting element and an oscillating circuit for supplying a pulse output to the light emitting element; the light emitted from the smoke detecting light emitting element is not directly received but is emitted. Smoke detection light-receiving element that receives scattered light, and a first-stage amplifier circuit that has an output adjustment variable resistor for amplifying the light-receiving output of this light-receiving element, and the first-stage output is further amplified. And a dividing resistor circuit having a variable resistor for adjusting a reference voltage, to which the received light amplification output of the receiving portion is supplied, and on / off depending on a dividing voltage of the dividing resistor circuit. A fire discriminating unit having a transistor for discriminating a fire; an output of a transistor of the fire discriminating unit is connected to an output of an oscillation circuit of the light emitting unit, and a pulse output of the oscillation circuit is synchronized. The fire discrimination section A storage circuit that determines whether or not a transistor has been continuously turned on a plurality of times and produces a detection output when it is determined that the transistor has been turned on a plurality of times continuously; and a fire signal transmission that turns on by the detection output of the storage circuit. A fire signal transmitting section including a switching element for operation and an operation indicator lamp connected in series with the switching element; a power supply for supplying power to the light emitting section, the light receiving section, the fire determining section, and the storage circuit. A photoelectric circuit comprising a transistor having a constant current circuit between a collector and a base, and a constant voltage circuit having a Zener diode connected between the base of the transistor and a ground terminal. Smoke detector. 2. The light emitting section includes a pulse width expansion circuit for expanding and outputting the pulse width of the pulse output of the oscillation circuit, and the output of the pulse width expansion circuit is an operation indicator lamp of the fire signal transmission section. 2. The photoelectric smoke detector according to claim 1, wherein the photoelectric smoke detector is connected to. 3. A sensor output circuit having a transistor whose base is connected to a connection point between an output end of the light emitting section and a divided resistance circuit of the fire discrimination section and whose emitter is grounded through an output resistance is provided. The photoelectric smoke detector according to claim 1 or 2, wherein 4. A constant current circuit, a junction type field effect transistor having a drain connected to the collector of the transistor and a gate connected to the base of the transistor, and a resistor connected between the source and the gate of the field effect transistor. And, and
2. The photoelectric smoke detector according to 2 or 3. 5. A test circuit comprising a reed switch which is turned on by magnetism from the outside of the sensor and a switching element which is provided in parallel with the reed switch and which is turned on by a test signal from the outside of the sensor; 3. A parallel circuit of a reed switch and a switching element of a test circuit is provided in parallel with a gain control resistor of a second stage amplifier circuit of the light receiving section.
3. The photoelectric smoke detector according to 3 or 4. 6. The fire signal transmission part includes a transistor in parallel with the operation indicator lamp, and the collector of the transistor
6. The photoelectric smoke detector according to claim 1, wherein a Zener diode is provided between the bases, and a resistor is connected between the base and the emitter. 7. An oscillating circuit which produces a pulse output; a smoke detecting light emitting element of a light emitting section whose lighting is controlled by the pulse output of the oscillating circuit; and a scattered light of smoke emitted from the smoke detecting light emitting element. A smoke detecting light emitting element for receiving the light; and an amplifier circuit having an output adjusting variable resistor for amplifying the light receiving output of the light emitting element and adjusting the amplified output to a predetermined output value; A fire discriminating section which operates when a predetermined level is reached and produces a discriminant output and which has a variable resistor for adjusting a reference voltage for regulating a predetermined level for fire discriminating to a predetermined value; A photoelectric smoke detector, comprising: a fire signal transmitter for transmitting a fire signal; 8. The photoelectric smoke detector according to claim 7, wherein the output adjusting variable resistor is provided as a feedback resistor of the amplifier circuit. 9. A fire discrimination section, a series resistance circuit comprising a first fixed resistance to which an amplified output of the amplification circuit is supplied, a reference voltage adjusting variable resistance and a second fixed resistance, and the second fixed resistance. 8. The photoelectric smoke detector according to claim 7, comprising a switching transistor having a base and an emitter connected to both ends of a fixed resistor. 10. A storage circuit is provided in which the output of the transistor of the fire discriminating unit and the output of the oscillation circuit of the light emitting unit are connected, and the storage circuit has a current equal to or lower than the current for driving the switching element of the fire signal transmitting unit. A photoelectric smoke detector, characterized in that it is provided with control means for operating. 11. A storage circuit determines whether or not a transistor of a fire determination unit is continuously turned on a plurality of times in synchronization with a pulse output of an oscillation circuit, and confirms that the transistor is turned on a plurality of times continuously. 11. The photoelectric smoke detector according to claim 10, wherein a detection output is generated when the determination is made. 12. A light emitting section having a smoke detecting light emitting element, a light receiving section having a smoke detecting light receiving element, a fire discriminating section for discriminating a fire based on a light receiving output of the light receiving element, and a malfunction of a detector are prevented. And a constant voltage circuit for supplying power to each of the storage circuit and the constant voltage circuit.
A photoelectric smoke detector, comprising: a transistor having a constant current circuit between bases; and a zener diode connected between the base of the transistor and a ground terminal. 13. A constant current circuit having a junction type field effect transistor having a drain connected to the collector of the transistor and a gate connected to the base of the transistor, and a resistor connected between the source and the gate of the field effect transistor. 13. The photoelectric smoke detector according to claim 12, wherein the photoelectric smoke detector comprises: 14. A smoke detecting light emitting element, an oscillating circuit for supplying a pulse output for emitting light to the light emitting element, and a pulse width expanding circuit for expanding a pulse width of a pulse output of the oscillating circuit to output an expanded pulse. And a light-receiving portion including a smoke-detecting light-receiving element that receives scattered light due to smoke of light emitted from the light-emitting element; and a detection output of the light-receiving portion exceeds a fire determination level. A fire discriminator that occasionally produces a discriminative output; a fire signal transmitting switching element that transmits a fire signal based on the discriminative output of the fire discriminator; and an operation indicator lamp that displays the enlarged pulse output of the pulse width enlargement circuit. A photoelectric smoke detector, comprising: a fire signal transmitter. 15. A smoke detecting light emitting element, an oscillating circuit for supplying a pulse output for emitting light to the light emitting element, and a pulse width expanding circuit for expanding a pulse width of a pulse output of the oscillating circuit to output an expanded pulse. And a light-receiving portion including a smoke-detecting light-receiving element that receives scattered light due to smoke emitted from the light-emitting element; and an analog that converts a detection output of the light-receiving portion into a digital signal. A signal transmission unit including a digital conversion circuit; and an operation indicator lamp that outputs the digital signal converted by the analog-digital conversion circuit and that is supplied with the expanded pulse output of the pulse width expansion circuit. A photoelectric smoke detector characterized by being equipped with. 16. The photoelectric smoke detector according to claim 14, wherein the operation indicator lamp is provided in series with the switching element for transmitting a fire signal.