JPS5844466Y2 - Storage type fire detector - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a storage type fire detector, and particularly relates to an improvement of a sensitivity setting mechanism in a storage type fire detector.

Conventionally, in photoelectric smoke detectors, ion smoke detectors, semiconductor heat detectors, etc. other than fire detectors using mechanical contacts that use heat-sensitive members such as bimetallic diaphragms, the purpose of reducing the current consumption of the detector is to A so-called pulse drive method is used to periodically monitor fires.

In addition, in order to prevent false alarms from occurring due to non-fire factors that tend to occur in a short period of time, such as external noise or cigarette smoke,
It has been put into practical use as a so-called storage-type fire detector that issues an alarm only when a fire condition continues for, for example, 20 seconds or more.

Since such a storage type fire detector is of a pulse drive type as described above, if the pulse interval is longer than the storage time, the function as a storage type fire sensor will be lost.

Therefore, in general, fire monitoring is performed at a pulse interval of 8 seconds if the accumulation time is less than the accumulation time, for example, if the accumulation time is 20 seconds or more, and a fire alarm is issued only when a fire is identified as a fire four or more times in a row. A digital counting circuit or an analog counting circuit is used to count the number of fire identifications.

On the other hand, the sensitivity setting method for storage type fire detectors is carried out by placing the detector in a test device filled with smoke at a predetermined concentration, but the detector will not operate until more than 20 seconds have elapsed. You will not know whether the sensor has been used or not, and you will end up spending at least 20 seconds or more each time you set and adjust the sensitivity of the sensor.

Therefore, in the case of storage type fire detectors, it takes a considerable amount of work time to set the sensitivity of the sensor to a predetermined value, resulting in very poor work efficiency.

The present invention was developed in view of the above-mentioned situation, and in order to set the sensitivity of a storage type fire detector in a short time, a detection signal exceeding a reference level is applied to the output terminal of a comparison circuit as a fire signal to the counting circuit. The present invention provides a storage type fire detector equipped with a sensitivity checking circuit means for transmitting an output signal to a test device.

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

FIG. 1 is a block diagram illustrating an embodiment of the storage type fire detector of the present invention using a scattered light type as an example, in which 1 is a rectifier circuit equipped with a diode bridge, etc. connected to a line from a receiver; 2 is a constant voltage circuit that stabilizes the power supply voltage from the rectifier circuit 1; 3 is a light source drive circuit that drives the light source provided in the smoke detector; 4 is an oscillation circuit that operates the light source drive circuit 4 intermittently; 5; 6 is a light receiving amplification circuit that detects scattered light generated when light from a light source is irradiated onto smoke that has entered the smoke detection section;
7 is a comparator circuit that compares the output of the light receiving amplification circuit 5 with a reference level and when it reaches the reference level or higher performs an inverted operation and produces an output. 7 counts the number of times the comparator circuit 6 operates and produces an output when a set count is reached. The counting circuit 8 is a switching circuit activated by the output of the counting circuit 7 to transmit a fire signal to the receiver.

Regarding storage type fire detectors with this kind of circuit configuration,
A sensitivity check circuit 10 is connected to the output end of the comparator circuit 6 for taking out the fire signal output regardless of the operation of the counting circuit 7.

FIG. 3 shows the specific circuit configuration of the circuit section 9 including the comparison circuit 6, the counting circuit 7, and the sensitivity checking circuit 10 in the embodiment of FIG. 1.

That is, the comparator circuit 6 uses the operational amplifier 11 as a comparator, and one input terminal (→ is connected to the previous stage light receiving amplifier circuit 5
At the same time, the differential output voltage Vd of
The reference voltage Vref extracted through the adjustment of step 2 is input.

The magnitude of this reference voltage Vref determines the sensitivity of the sensor.

Further, the counting circuit 7 is made up of counters 12a and 12b connected in series, and the counter 12a at the previous stage is used as a bumper, and when the counter 12b at the next stage reaches a predetermined count, it produces an output to the switching circuit 8.

The output setting count number of this counter 12b determines the accumulation operation time of the sensor in relation to the drive pulse period.

Incidentally, the integrator circuit consisting of the inverter (2), the resistor R, and the capacitor C serves as a resent circuit for the counters 12a and 12b.

The sensitivity checking circuit 10 connected to the output terminal of the comparator circuit 6, that is, the operational amplifier 11 that operates as a comparator, has a circuit configuration in which a series circuit of a resistor R4 and an issuing diode 13 is connected in parallel with a resistor R3, as an example. The differential output Vd of the light receiving amplification circuit 5 with respect to the comparison circuit 6 is Vd
>Vref, the output of the operational amplifier 11 is inverted, and this inversion operation causes a drive current to flow through the light emitting diode 13 of the sensitivity checking circuit 10, which irradiates pulsed light.

As shown in FIG. 3, this light emitting diode 13 is provided on an internal printed circuit board facing a through hole 15 formed at a position approximately at the center of the back surface of the sensor base 14.
Pulsed light from the light emitting diode 13 passes through the through hole 15 and is irradiated to the outside.

In addition, 16 is a mounting terminal plate with a twist lock structure that is fitted into a socket base fixed to a ceiling surface etc.
is a drainage hole.

On the other hand, the sensor sensitivity testing apparatus is equipped with a socket base in the test chamber into which the sensor base 14 shown in FIG.
A through hole facing the light emitting diode 13 is similarly provided, and a photodiode, a phototransistor, etc. as a light receiving element for receiving light from the light emitting diode 13 is mounted.

FIG. 4 shows the configuration of a test device 25 that receives light from a light emitting diode 13. A light receiving element 18 is provided opposite the light emitting diode 13, and the photoelectric conversion output from the light receiving element 18 is transmitted through an amplifier 19. Trigger the monostable multipipe rake 20, and this monostable multivibrator 2
The display device 21 is activated by the output of 0, so that confirmation can be made using a buzzer, lamp, etc.

With the sensitivity confirmation circuit means for the storage type fire detector disclosed in the above embodiments, the result of setting the sensitivity of the sensor does not depend on the storage operation time, and the pulse drive interval determined by the oscillation cycle of the oscillation circuit 4, For example, the drive of the light emitting diode 13 by the reversal operation of the comparator circuit every 8 seconds will be displayed on the sensitivity testing device 25, and the desired set sensitivity can be adjusted in a short time while checking the operating state.

In addition, as another embodiment of the sensitivity confirmation circuit 10 in FIG. 1, instead of the light emitting diode 130, a connection terminal for directly connecting the input end of the comparison circuit 6 to the input of the test device 25 is provided with a twist-lock structure on the back surface of the sensor base. It may be provided.

As explained above, the storage type fire detector of the present invention is newly equipped with a sensitivity checking circuit means for taking out the output of the comparison circuit located before the counting circuit in order to apply it to the input section of the sensitivity testing device. As a result, the operation of the storage type fire detector sensitivity setting can be checked at every pulse drive interval of less than 20 seconds, without having to pass the storage operation time of 20 seconds or more, reducing the work time required for sensitivity setting. This greatly shortens the time and improves the sensitivity adjustment work efficiency.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an embodiment of the storage type fire detector of the present invention, and Fig. 2 is a circuit section 10 in the embodiment of Fig. 1.
FIG. 3 is an explanatory diagram showing the mounting structure of a light emitting diode for sensitivity confirmation according to the present invention, and FIG. 4 is a block diagram of a sensitivity testing device used in the present invention. 1... Rectifier circuit, 2... Constant voltage circuit,
3... Light source drive circuit, 4... Oscillation circuit, 5... Light receiving amplification circuit, 6... Comparison circuit, 7... Counting Circuit, 8... Switching circuit, 9... Circuit section, 10... Sensitivity confirmation circuit, 11... Operational amplifier, 12a, 1
2b... Counter, 13... Light emitting diode, 14... Sensor base, 15...
...Through-TL16...Mounting terminal board, 17...
... Water drain hole, 18 ... Light receiving element, 19 ...
... Amplifier, 20 ... Monostable multivibrake, 21 ... Display device, 25 ...
Sensitivity test equipment.

Claims (4)

[Scope of utility model registration request] (1) A detection circuit that intermittently detects the amount of physical change caused by a fire by pulse driving an oscillation circuit that oscillates at a predetermined frequency, and a comparison circuit that produces an output when the output of the detection circuit reaches a reference level or higher. , a storage type fire detector having a counting circuit that counts the output of the comparison circuit, and a switching circuit that issues an alarm based on the output of the counting circuit, wherein the output terminal of the comparison circuit is connected to a sensitivity test device as an input section. A storage type fire detector characterized by being provided with a confirmation circuit means. (2) The storage type fire detector according to item 1, wherein a light emitting diode that emits light by the output of the comparator is connected to the output terminal of the comparator as the sensitivity checking circuit means. (3) The storage type fire detector according to item 2 above, wherein a light emitting diode as a detection confirmation circuit means is provided in the sensor facing a through hole formed approximately in the center of the back surface of the sensor base. (4) The storage type fire detector according to item 1, further comprising a connection terminal for connecting the output of the comparison circuit to a sensitivity testing device as the sensitivity checking circuit means.