JPH0119199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric smoke detector.

Automatic fire alarm equipment with photoelectric smoke detectors is
Although periodic inspections are required every year, there is no guarantee that the equipment will operate normally, as abnormalities may occur between one periodic inspection and the next, or may not be discovered due to omissions in inspections. . In particular, with photoelectric smoke detectors, abnormalities other than malfunctions are unknown until a person inspects each one, and when it comes to sensitivity, the operating point must be investigated through a smoke test, which makes inspection nearly impossible. It was.

Therefore, an object of the present invention is to provide a photoelectric smoke detector that can notify of its own abnormality.

An embodiment of the invention is shown in FIGS. 1 and 2. That is, as shown in FIG. 1, this photoelectric smoke detector includes a first light emitting element 1 that irradiates light to a smoke sensing section A, and a drive circuit section 2 that drives the first light emitting element 1 to turn on. and smoke particles B that have entered the smoke sensing area A.
Scattered light of the irradiation light of the first light emitting element 1 (arrow
a first light receiving element 3 that receives light (indicated by _C1 ); a first light receiving circuit section 4 that generates a smoke detection signal in response to the output of the first light receiving element 3 exceeding a predetermined value;
A fire alarm output section 5 that generates a fire alarm output in response to the output of the first light receiving circuit section 4, and a smoke sensing section A.
The irradiation light of the first light emitting element 1 (arrow C ₂
a second light receiving element 6 that receives light (indicated by The abnormality notification output section 8 generates an abnormality notification output in response to the output of the light receiving circuit section 7. In this case, an optical coupling circuit consisting of a second light emitting element 9 and a third light receiving element 10 is interposed between the second light receiving circuit section 7 and the abnormality notification output section 8, and the first
and second light emitting elements 1 and 9, first and second light receiving elements 3 and 6, drive circuit section 2, first and second
The light receiving circuit parts 4 and 7 and the fire alarm output part 5 are housed in the sensor body, and the third light receiving element 10 and the abnormality alarm output part 8 are housed in the sensor base. Note that 11, 12, and 13 are the first light emitting element 1 and the first and second light receiving elements 3, 6.
A light shielding member surrounding each of the first and second parts.
a light emitting element 1, a first and a second light receiving element 3,
6. The drive circuit section 2 and the first and second light receiving circuit sections 4 and 7 together form a sensor internal circuit.

FIG. 2 is a circuit diagram showing a specific circuit configuration of this photoelectric smoke detector, in which the fire alarm output section 5 includes a thyristor 5a, and the abnormality alarm output section 8 is composed of an output section main body 8a and a transistor 8b. , the sensor base has a positive power terminal 14 and a negative power terminal 1.
5. Fire alarm output terminal 16, abnormality alarm output terminal 1
7 and input terminals 18 and 19, the negative side power supply terminal 15 and the input terminal 19 are connected, the third light emitting element 20 is connected between the fire alarm output terminal 16 and the input terminal 18, and the positive side Power is supplied to the output section main body 8a from the power supply terminal 14 and the negative side power supply terminal 15, and a series circuit of a transistor 8b and a fourth light emitting element 21 to which a signal from the output section main body 8a is applied to the base is connected to the abnormality notification output terminal 17. It is connected between the negative side power supply terminal 15 and the negative side power supply terminal 15.

Next, the operation of this photoelectric smoke detector will be explained with reference to FIG. In this photoelectric smoke sensor, a first light emitting element 1 is intermittently turned on in response to a pulse signal given by a drive circuit section 2 to irradiate a smoke sensing section A with light. The second light receiving element 6 receives the irradiated light from the first light emitting element 1 and generates an output pulse as shown in FIG. 3A.

The second light receiving circuit section 7 generates an output pulse as shown in FIG. 3B in synchronization with the output pulse of the second light receiving element 6 to drive the second light emitting element 9 to light up. The first light emitting element 1 stops emitting light due to an abnormality in the internal circuit, and the second light receiving element 6 stops emitting light due to deterioration of the first light emitting element 1 itself or dirt on its surface.
When the level of the output pulse becomes less than 50% of the initial value (indicated by the broken line D) as shown in Figure 3A, the generation of the output pulse is stopped and the second light emission is started as shown in Figure 3B. The lighting drive of the element 9 is stopped.

In the abnormality notification output section 8, when a light pulse is given from the second light emitting element 9 to the third light receiving element 10, the output section main body 8a turns off the transistor 8b as shown in FIG. 3C. The abnormality notification line (17→21→8b→15) is opened and the fourth light emitting element 21 is turned off, but when the light pulse is no longer given to the third light receiving element 10, the output section main body 8a is switched to the transistor 8b. is turned on as shown in FIG. 3C, the abnormality notification line is closed, and the fourth light emitting element 21 is turned on to notify an abnormality and transmit an abnormality signal to a fire receiver (not shown) or the like.

Further, when the sensor main body is removed from the sensor base in the energized state, the optical coupling between the second light emitting element 9 and the third light receiving element 10 is released,
Since the optical pulse does not reach the third light receiving element 10, the output section main body 8a turns on the transistor 8a to close the abnormality notification line, and the fourth light emitting element 21
It lights up to notify you of an abnormality and also sends an abnormality notification signal to a fire receiver, etc.

Further, even when large particles such as insects and dust enter the smoke sensing section A, the amount of light reaching the second light receiving element 6 becomes less than 50% of the initial value, and an abnormality notification operation is performed.

Based on the abnormality notification signal transmitted from the photoelectric smoke detector, the receiver side can determine that an abnormality has occurred in the photoelectric smoke sensor. Note that if multiple photoelectric smoke detectors are connected in parallel to the same line, such as a fire receiver, it is not possible to determine which one is abnormal; The fourth light emitting element 21 at the installation location
Just make sure that it is lit.

On the other hand, if no smoke particles have entered the smoke sensitive part A, the irradiated light from the first light emitting element 1 is not scattered, and therefore no output is generated at the first light receiving element 3.
The first light receiving circuit section 4 does not generate an output, the thyristor 5a of the fire alarm output section 5 is in a cutoff state, the fire alarm line (16→20→5a→15) is opened, and the third light emitting element 20 is activated. The lights are off. However, when smoke particles B enter the smoke sensing part A, the irradiated light from the first light emitting element 1 is scattered, and the light emitted from the first light receiving element 3 is scattered.
The first light-receiving element 3 begins to generate an output pulse. When the concentration of smoke particles B becomes a predetermined value or more, the level of the output pulse of the first light receiving element 3 also becomes a predetermined value or more, and the first light receiving circuit section 4 detects this and outputs a fire alarm output section 5. The thyristor 5a is brought into conduction, the fire alarm line is closed, and the third light emitting element 20 is turned on to notify of a fire and transmit a fire alarm signal to a fire receiver or the like.

In addition, when giant particles enter the smoke sensing section A, the scattered light increases and a fire alarm is activated, but at the same time an abnormality alarm is also activated. You can judge by.

Note that even if smoke particles B enter the smoke sensing section A and a fire alarm operation is performed, an abnormality alarm operation is not performed. The reason is as follows. That is,
Assuming that the optical path length (linear distance) between the first light emitting element 1 and the second light receiving element 6 is 10 cm at maximum, the operating point (20
Even if uniform smoke particles B (%/m) exist in the smoke sensitive area A, the light attenuation rate α is α = 1 - (0.8) ^0.1 = 0.022, which is approximately 2.2%, so the attenuation is 50%. This means that there is no problem at all.

In addition, the occurrence of a fire can be determined on the receiver side in the same way as when an abnormality has occurred, and if multiple photoelectric smoke detectors are connected in parallel to the same line, a third It is sufficient to confirm that the light emitting element 20 is lit.

As a result of this configuration, the first light emitting element 1 stops emitting light due to an abnormality in the internal circuit of the sensor, deterioration of the first light emitting element 1 itself and dirt on its surface, large particles entering the smoke sensing part A and sensing. It is possible to notify abnormalities such as detachment of the main body from the sensor base.

As described above, the photoelectric smoke detector of this invention is
A first light emitting element that irradiates light to the smoke sensing section, a drive circuit unit that lights and drives the first light emitting element, and a control circuit that controls the irradiation of the first light emitting element by smoke particles that have entered the smoke sensing section. A first light receiving element that receives scattered light; a first light receiving circuit that generates a smoke detection signal in response to an output of the first light receiving element exceeding a predetermined value; a fire alarm output section that generates a fire alarm output in response to the output; a second light receiving element that receives the irradiation light of the first light emitting element that has passed through the smoke sensing section; a second light receiving circuit section that generates an abnormality detection signal in response to a predetermined output value or less; an abnormality notification output section that generates an abnormality notification output in response to the output of the second light receiving circuit section; an optical coupling circuit comprising a light-emitting element and a third light-receiving element and interposed between the second light-receiving circuit section and the abnormality notification output section, and the light is turned on in response to an abnormality notification output from the abnormality notification output section. an abnormality indicator, at least the third light receiving element, the abnormality notification output section, and the abnormality indicator are accommodated in the sensor base, and at least the first and second light emitting elements, the first and second light receiving elements are housed in the sensor base. Since the element and the second light receiving circuit section are housed in the sensor body mounted on the sensor base, the following effects are achieved.

That is, since an abnormality indicator is provided that lights up in response to the abnormality notification output from the abnormality notification output section, it is possible to notify a person near the sensor of an abnormality in the first light emitting element by lighting the abnormality indicator. .

Moreover, an optical coupling circuit including the second light emitting element and the third light receiving element is interposed between the second light receiving circuit section and the abnormality notification output section, and at least the third light receiving element, the abnormality notification output section and the abnormality A display device is housed in a sensor base, and at least first and second light emitting elements, first and second light receiving elements, and a second light receiving circuit section are housed in a sensor body mounted on the sensor base. Therefore, the second part of the sensor body
The abnormal signal output from the light receiving circuit of the sensor can be transmitted to the abnormal alarm output section of the sensor base without contact. Electrical contact terminals are no longer required, making it easier to attach and remove the sensor body from the sensor base.
Operability can be improved.

In addition, it does not use electrical contact terminals, which tend to have a complicated connection structure and a large shape, and simply arranges the second light-emitting element on the sensor body side and the third light-receiving element on the sensor base side facing each other. As a result, the sensor main body and the sensor base can each be made smaller, and the whole can therefore be made smaller.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a photoelectric smoke detector according to an embodiment of the present invention, Fig. 2 is a specific circuit diagram of its main parts,
FIGS. 3A, B, and C are waveform diagrams of each part. DESCRIPTION OF SYMBOLS 1... First light emitting element, 2... Drive circuit section, 3
...first light receiving element, 4...first light receiving circuit section,
5... Fire alarm output unit, 6... Second light receiving element,
7... Second light receiving circuit unit, 8... Abnormality notification output unit, 9... Second light emitting element, 10... Third light receiving element,... Sensor main body,... Sensor base,
A...Smoke sensing part, B...Smoke particles.

Claims (1)

[Claims] 1. A first light emitting element that irradiates light to the smoke sensing part, a drive circuit unit that drives the first light emitting element to turn on,
a first light-receiving element that receives scattered light of the light irradiated by the first light-emitting element due to smoke particles that have entered the smoke-sensing section; a first light receiving circuit section that generates a signal; a flame alarm output section that generates a flame alarm output in response to the output of the first light receiving circuit section; and the first light emitting element that has passed through the smoke sensing section. a second light-receiving element that receives the irradiation light; a second light-receiving circuit that generates an abnormality detection signal in response to an output of the second light-receiving element being equal to or less than a predetermined value; an abnormality notification output section that generates an abnormality notification output in response to the output of the circuit, and an abnormality notification output section that includes a second light emitting element and a third light receiving element, and is interposed between the second light receiving circuit section and the abnormality notification output section. comprising an optical coupling circuit and an abnormality indicator that lights up in response to an abnormality notification output from the abnormality notification output section, and at least the third light receiving element, the abnormality notification output section, and the abnormality indicator are housed in a sensor base. and a photoelectric smoke sensor, in which at least the first and second light emitting elements, the first and second light receiving elements, and the second light receiving circuit section are housed in a sensor main body mounted on the sensing base.