JPH04104392U - photoelectric smoke detector - Google Patents

Abstract

(57) [Summary] [Purpose] By emitting light from the light emitting circuit after the operation of the light receiving circuit and amplifier circuit has stabilized, the light emitting time is shortened, power consumption is reduced, and smoke is accurately detected. Provide smoke detectors. [Configuration] A power supply switch circuit 9 that supplies power to the light receiving circuit 2 and the amplifier circuit 3, an oscillation circuit 10 that turns on and off the power supply switch circuit 9 at regular intervals, and a power supply switch circuit 9 that supplies power to the light receiving circuit 2 and the amplifier circuit 3; The light emitting circuit 1 includes a light emitting timing circuit 11 that forms the light emitting timing of the light emitting circuit 1.
After power is supplied to the light receiving circuit 2 and the amplifier circuit 3,
It is configured to emit light with a delay of a predetermined period.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a photoelectric smoke detector.

0002

[Conventional technology]

Photoelectric smoke detectors that have been devised in the past include, for example, Japanese Patent Application Laid-open No. 62-197893. There are some that are listed in the publication. A circuit diagram of this smoke detector is shown in FIG. this Smoke detectors operate as follows: 1. The light emitting element blinks at a constant cycle. 2. When the light receiving element receives the scattered light of smoke, it outputs a "smoke present" signal. 3. The "smoke present" output of the light receiving element is amplified by a two-stage operational amplifier. 4. The "smoke present" signal output from the operational amplifier is input to the AND circuit. 5. The “smoke present” signal and the signal from the pulse generator are input to the AND circuit together. When this occurs, it outputs a “smoke present” signal. 6. The “smoke present” signal of the AND circuit is generated by the operational amplifier, which is a differential amplifier, and the AND circuit. The signal passes through the path and is input to the flip-flop. The AND circuit is a “smoke presence” signal. When the signal from the pulse generator and the signal from the pulse generator are input, the “smoke present” signal is sent to the flip-flop. input to the set terminal of the top. 7. “H” signal, which is a “smoke present” signal, is input to the set terminal of the flip-flop. Then, a "smoke present" signal is output to the output terminal Q. 8. The “smoke present” signal output from the flip-flop is passed through the OR circuit and the au pair. The signal passes through the lamp and is input to the buzzer, causing the buzzer to sound.

0003 This photoelectric smoke detector blinks the light-emitting element, and when the light-emitting element lights up, It is possible to select the "smoke" signal and sound the buzzer, eliminating the influence of external noise. The sound can be reduced.

0004 However, in a photoelectric smoke detector with this circuit configuration, the output signal is from the light receiving element. Since the circuit that amplifies the “Smoke present” signal is constantly connected to the power supply, power consumption is reduced. The disadvantage is that it is large.

[0005] In order to eliminate this drawback, the present inventor first proposed the He devised a smoke detector that is now available in Japan.

[0006] This smoke detector is characterized by the following circuit configuration. That is, the light emitting circuit , a power supply switch that supplies power to the light receiving circuit and the amplifier circuit, and a power supply switch that supplies power to the light receiving circuit and the amplifier circuit. It is equipped with an oscillation circuit that turns on and off the supply switch at regular intervals.

[0007] The output of the oscillation circuit controls the on/off of the power supply switch. power supply switch In the on state, power is supplied to the light emitting circuit, light receiving circuit, and amplifier circuit. When the power supply switch is off, power is supplied to the light emitting circuit, light receiving circuit, and amplifier circuit. It is configured so that it is not provided. Therefore, when the power supply switch is off, , these circuits do not operate and therefore do not consume power. As a result, the smoke detector itself power consumption can be reduced.

[0008]

[Problem that the idea aims to solve]

By the way, this smoke detector has a light emitting circuit and a receiver when the power supply switch is off. Power is supplied to the optical circuit and the amplifier circuit at the same time. On the other hand, the light receiving time The circuit and amplifier circuit start up transiently when power is supplied, so Its operation is unstable between the two. Therefore, the light emitting circuit emits light and the scattered light Even if the light is received, the outputs of the light receiving circuit and the amplifier circuit are not determined. As a result, this Smoke detectors will not work properly. In order to eliminate this drawback, the light receiving circuit It may be possible to extend the light emitting time of the light emitting circuit until the operation of the amplifier circuit stabilizes. Ru. However, extending the light emitting time increases the current consumption of the light emitting circuit, which significantly increases the There are concerns that it will increase power consumption.

[0009]

[Means to solve the problem] The present invention has the following circuit configuration. In other words, light is emitted into the smoke path. The light emitting circuit that emits light from the light emitting circuit is reflected by fire smoke and the scattered light is received. A light receiving circuit that emits light and converts the intensity of the received light into an electrical signal, and increases the output of the light receiving circuit. The output of the amplifier circuit is accumulated and the buzzer sounds when the accumulated amount reaches the set value. and an accumulation circuit that outputs a signal. Furthermore, power is supplied to the light receiving circuit and the amplifier circuit. The power supply switch that supplies the power and turns this power supply switch on and off at regular intervals. An oscillation circuit and a light emitting device that determines the light emission timing of the light emitting circuit according to the output of the oscillation circuit. The light emitting circuit is equipped with a timing circuit, and the light emitting circuit supplies power to the light receiving circuit and the amplifier circuit. It is configured to emit light after a predetermined period of time after being supplied with the light.

0010

[Effect]

According to the present invention, the light emitting circuit, after power is supplied to the light receiving circuit and the amplifier circuit, Light is emitted after a predetermined period of time. Therefore, when the light emitting circuit emits light, the light receiving circuit and amplification A predetermined period of time has passed since power was supplied to the circuit, and during this period the light receiving circuit and amplifier circuit operation is stable. As a result, the light emitting circuit emits light and receives the scattered light. Therefore, the presence or absence of smoke can be accurately determined.

[0011]

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings.

0012 The smoke detector of the present invention includes a light emitting circuit 1 that emits light in the path of smoke, and a light emitting circuit 1 that emits light in the path of smoke. Light is reflected by fire smoke and the scattered light is received, and the intensity of the received light is converted into an electrical signal. A light receiving circuit 2 for converting, an amplifying circuit 3 for amplifying the output of the light receiving circuit 2, and an amplifying circuit 3 A comparator circuit 4 that compares the output of the comparator with a reference voltage, and an accumulation circuit that accumulates the output of the comparator circuit 4. 5 and a buzzer circuit 6 that generates a buzzer sound based on the output of the storage circuit 5. Ru.

[0013] Furthermore, this smoke detector has a driving battery 7 and a constant voltage circuit that stabilizes the voltage of the battery 7. a power supply switch circuit 9 that supplies power to the light receiving circuit 2 and the amplifier circuit 3; , an oscillation circuit 10 that turns on and off the power supply switch circuit 9 at regular intervals, and an oscillation circuit 10 that turns on and off the power supply switch circuit 9 at regular intervals A light emission timing circuit that forms the light emission timing of the light emission circuit 1 according to the output of the circuit 10. It is equipped with road 11.

[0014] The light emitting circuit 1 includes a light emitting element LED that emits light toward the smoke sensing section. , the light emitting element LED emits light at a predetermined period based on the output from the light emission timing circuit 11. Ru.

[0015] The light receiving circuit 2 includes a light receiving element PD. The light receiving element PD is connected to the light emitting element LED. The emitted light is reflected by smoke when a fire breaks out, and the device is placed in a position to receive this scattered light. Additionally, this photodetector PD is placed inside a dark box that allows smoke to enter but outside light cannot. It will be done. When the light-receiving element PD receives scattered light from smoke, the light-receiving circuit 2 generates a very small voltage. Generates a “Smoke present” signal.

[0016] The amplifier circuit 3 is composed of operational amplifiers IC1 and IC2. "Amplify the signal. The resistor R30 connected to the input terminal of the operational amplifier IC2 is This is a variable resistor that adjusts the sensitivity of the amplifier circuit.

[0017] The comparison circuit 4 includes resistors R11 and R12 and a comparator IC3. Comparator IC3 connects the reference voltage formed by resistors R11 and R12 and the amplification voltage Compare with the "smoke present" signal. Comparison circuit 4 detects the smoke floating in the smoke sensing section. The light receiving circuit 2 receives scattered light due to dust, etc., and stores it as a "smoke presence" signal. This prevents signals from being output to line 5, and only signals with a predetermined reference voltage or higher are It is designed to be output to the storage circuit 5.

[0018] The storage circuit 5 includes two flip-flops IC4 and IC5 and a flip-flop I. The output terminal Q of each of C4 and IC5 is connected to the input AND element IC6. Ru. These flip-flops IC4 and IC5 operate as a shift register. input When the "smoke present" signal is input to the input terminal D of the side flip-flop IC4, the output The force becomes H. This H signal is input to the AND element IC6, and the resistor R15 The current flows through the capacitor C4, and is output to the input terminal D of the output side flip-flop IC5. I don't feel strong. This capacitor C4 is set to be charged by one H signal. There is. If the “smoke present” signal is input to IC4 continuously after this, the H signal of IC4 The signal is input to the AND element IC6, and the capacitor C4 is already charged. Therefore, it is also input to the input terminal of IC5. At this time, the output terminal Q of IC5 is an H signal. This H signal is input to AND element IC6. As a result, the AND element The slave IC 6 outputs an H signal, and this H signal is input to the buzzer circuit 6 and the buzzer is activated. It rings. The “smoke present” signal is continuously input to the input side flip-flop IC4. If not, capacitor C4 is discharged when the output of IC4 is L, and the initial state is Return to In this way, this smoke detector sounds the buzzer when it detects smoke twice in a row. This prevents malfunctions.

[0019] Now, the oscillation circuit 10 is composed of a plurality of inverter ICs 7 to 10. These are driven by a constant voltage circuit 8. Here, the constant voltage circuit stabilizes the 6V battery voltage. A voltage VB of 4V is generated by regulating the storage circuit 5, an oscillation circuit 10, and a light emission timing circuit. This is a power source for driving the circuit 11, the power supply switch circuit 9, and the light emitting circuit 1. Oscillation times The output of line 10 is low for period T2 (approximately 15 msec) with a period of T1 (approximately 10 sec). Output a signal (FIG. 3A).

[0020] The power supply switch circuit 9 includes a transistor Q2, and the oscillation circuit 10 generates an L signal. When the signal is being output, transistor Q2 becomes conductive and the light receiving circuit 2 and amplifier circuit 3 The voltage VC is supplied to the comparator circuit 4 and the comparator circuit 4 (FIG. 3B).

[0021] The light emission timing circuit 11 includes a resistor R23, capacitors C7 and C8, and an inverter IC. 11. The output of this circuit is shown in Figure 3C. That is, the L of the oscillation circuit 10 The output is delayed by T3 time from the output. This T3 is resistor R23 and capacitor C7.

[0022] The light emitting circuit 1 includes two stages of transistors Q3 and Q4 and resistors R24 to R29. , capacitors C9 and C10, and a light emitting element LED. The luminescence timing The output of the programming circuit 11 turns on transistors Q3 and Q4, and the light emitting element LED turns on. emits light (Figure 3D). This light emission time T4 is determined by resistor R26 and capacitor C9. It will be done.

[0023] According to the circuit configuration as described above, the light receiving circuit 2, the amplifier circuit 3, and the comparison circuit 4 are electrically connected. The light emitting element LED emits light with a delay of T3 after the power is supplied. During this period, the light receiving cycle The operations of the circuit 2, the amplifier circuit 3, and the comparison circuit 4 are stabilized.

[0024] Now, when smoke enters the sensing part as shown in Figure 3E, the operation of amplifier circuit 3 becomes stable. After that, output as shown in FIG. 3F. When this output exceeds the set level of comparator circuit 4, Comparison circuit 4 outputs to storage circuit 5 as shown in FIG. 3G. Here, as mentioned above, this smoke The detector is designed to sound a buzzer when it detects smoke twice in a row. Therefore, the output of the buzzer circuit 6 is as shown in FIG. 3H.

[0025]

[Effect of the idea]

According to the present invention, the light emitting circuit, after power is supplied to the light receiving circuit and the amplifier circuit, Light is emitted after a predetermined period of time. Therefore, when the light emitting circuit emits light, the light receiving circuit and amplification A predetermined period of time has passed since power was supplied to the circuit, and during this period the light receiving circuit and amplifier circuit operation is stable. As a result, the light emitting circuit emits light and receives the scattered light. Therefore, the presence or absence of smoke can be accurately determined.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram.

FIG. 2 is an example of a specific circuit.

FIG. 3 is a waveform diagram of each part.

FIG. 4 is a block circuit diagram of a conventional smoke detector.

[Explanation of symbols]

1 Light emitting circuit 2 Light receiving circuit 3 Amplification circuit 4 Comparison circuit 5 Storage circuit 6 Buzzer circuit 7 Batteries 8 Constant voltage circuit 9 Power supply switch circuit 10 Oscillation circuit 11 Light emission timing circuit

Claims (1)

[Scope of utility model registration request] Claim 1: A light emitting circuit that emits light into a smoke path, a light receiving circuit that receives the scattered light when the light emitted from the light emitting circuit is reflected by fire smoke, and converts the intensity of the received light into an electrical signal. In a photoelectric smoke detector, the photoelectric smoke detector includes a light receiving circuit, an amplifier circuit that amplifies the output of the light receiving circuit, and an accumulation circuit that accumulates the output of the amplifier circuit and outputs a buzzer signal when the accumulated amount reaches a set value. , a power supply switch that supplies power to the amplifier circuit, an oscillation circuit that turns on and off the power supply switch at regular intervals, and a light emission timing circuit that forms the light emission timing of the light emission circuit according to the output of the oscillation circuit. A photoelectric smoke detector in which the light emitting circuit emits light after a predetermined period of time after power is supplied to the light receiving circuit and the amplifier circuit.