JPS6360438B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fire detector equipped with a test device.

Conventionally, in order to perform a functional test on a fire detector, the detector is mounted on the ceiling and smoke or heat is actually applied using a smoke or heating tester.
Alternatively, remove the sensor from the ceiling and use a tester to apply a simulated electrical signal equivalent to smoke or heat to the detection part of the sensor, and check whether the sensor operates normally or remains inactive. etc. were being tested. However, with the former tester, it is difficult to delicately control the amount of smoke or the intensity of heat, making it impossible to conduct accurate tests, and with the latter tester, the sensor must be removed from the ceiling each time. There was a drawback that it took a while.

In view of the above points, the present invention provides a fire detector that allows a simple and accurate functional test to be performed with the fire detector attached to the ceiling.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In the figure, 1 is a photoelectric smoke detector mounted on the ceiling, 2 is a tester carried by the inspector, which consists of a power supply 3, a push button switch 4, a transistor 5, and a light emitting element 6, and when the switch 4 is pressed. Accordingly, a light beam is emitted, and a light receiving element 7 for receiving this light is provided on the outer surface of the sensor 1. Smoke detector 1 is
a light emitting element 9 that is pulse-lit by an oscillator 8;
A light receiving element 10 that receives scattered light generated when smoke enters the sensor, an amplifier 11 that amplifies the output of the light receiving element 10, a capacitor 12, and a resistor 13.
A series circuit of a resistor 15 and a capacitor 14 in parallel, a transistor 16 in which these series circuits are connected between the base and emitter, and a switching circuit 17 that operates when the transistor 16 is conductive.
It is composed of The test device also includes the light receiving element 7 and an amplifier 1 for amplifying the output of the light receiving element 7.
8, and a counter 19 as a signal selection circuit that counts the pulse output from the amplifier 18 and outputs the count values "1" and "2", respectively. Furthermore, the output of counting 1 is connected to a transistor 20 connected to the positive and negative terminals of the sensor via resistors 21 and 22.
A transistor 23 whose base is connected to the connection point of the resistors 21 and 22 is connected to the base of the resistor 24.
is connected between the positive terminal and the connection point t of the resistors 13 and 15, thereby forming a sensor inoperation test circuit. In this circuit, when the transistor 23 becomes conductive, the potential at the connection point t becomes _E1 , but in a normal state when the inside of the sensor is cleaned, the light emitted from the light emitting element 9 is diffusely reflected by the inner wall of the sensor. It is set sufficiently low so that even if the noise light output N generated by the noise is added, it will not exceed the fire level Vf (see Fig. 4B). Also, the output of count 2 is
A transistor 28 is connected to the base of a transistor 25 which is connected to the positive and negative terminals of the sensor through resistors 26 and 27, and a transistor 28 whose base is connected to the connection point between resistors 26 and 27 is connected to the positive terminal through a resistor 29. connection point t
A circuit for testing the operation of the sensor is configured. In this circuit, when the transistor 28 becomes conductive, the potential at the connection point t becomes E ₂ , and when the sensor is in a normal state, when the above noise output N is added, it reaches the fire level.
The voltage is set to sufficiently exceed Vf, and the transistor 16 is turned on, the switching circuit 17 is operated, and a fire signal is sent to the receiver.

Next, the operation of this sensor will be explained. In normal times, the light emitting element 9 is lit in pulses by the operation of the oscillator 8, but the light receiving element 10 and the amplifier 11
The output output through the sensor is only the noise light output N generated by diffuse reflection on the inner wall of the sensor, so the fourth
As shown on the left side of Figure A, the potential at point P does not exceed the fire level and continues to be monitored. Furthermore, when smoke from a fire enters the detector and scattered light is generated, the amplifier 11 generates an output that is the sum of the normal output N due to noise light and the output S due to scattered light, which is shown on the right side of Figure 4 A. As shown, the potential at point P exceeds the fire level Vf, transistor 16 becomes conductive, switching circuit 17 operates, and a fire signal is sent to a receiver (not shown).

Furthermore, the effects of the functional test will be explained. When the inspector presses the push button switch 4 of the tester 2 and emits light to the light receiving element 7 of the sensor 1 installed on the ceiling, the light is detected by the light receiving element 7 and amplified by the amplifier 18. , the pulse output "1" is counted in the counter 19, and the transistor 2
0 conducts. When the transistor 20 becomes conductive, the transistor 23 also becomes conductive, and the potential at the connection point t becomes the fourth
It is raised to E ₁ as shown in Figure B. In this state, if the sensor is properly cleaned and the noise output caused by diffusely reflected light inside the sensor is N, then the fourth
As shown on the left side of Figure B, the potential at point p is at the fire level.
It can be seen that the sensor does not exceed Vf, the transistor 16 and the switching circuit 17 do not operate, and the sensor is maintained normally. On the other hand, in this state, when the transistor 16 becomes conductive and the switching circuit 17 operates, and a bell or the like rings through the receiver, the output of noise light due to the diffusely reflected light within the sensor is as shown on the right side of Figure 4 (b). It is thought that the sensor operated with an increase in N', indicating that the sensor needs to be cleaned. Next, when the inspector presses the push button switch 4 and the light is emitted to the light receiving element 7, the light is detected by the light receiving element 7, the second pulse output is counted as "2" by the counter 19, and the transistor 25 becomes conductive. As a result, the transistor 28 also becomes conductive, and the potential at the connection point t rises to _E2 , which is higher than that in the non-operation test, as shown in FIG. 4C. Since the potential _E2 is selected to be sufficiently larger than the output S generated by scattered light during a fire, when the noise output N is added to this, the potential at point P exceeds the fire level, and the transistor 1 is activated as in the case of a fire.
6. The switching circuit 17 operates, a fire signal is sent to a receiver (not shown), and the sound of a bell indicates that the detector has operated normally. On the other hand, if the sensor does not operate in this state, it can be determined that the light-emitting element 9 or the light-receiving element 10 has become dirty and its output has decreased, or that these and other circuit elements have failed and are not operational.

In the above example, the case was explained in which it was applied to a photoelectric type smoke detector, but in the case of an ionization type smoke detector, the potential at the connection point between the inner and outer ion chambers, and in the case of a thermal type sensor, the potential at the connection point between the thermistor and the resistor is measured. If the potential is changed by the operation of the transistor 23 or 28, the present invention can be similarly implemented in other types of sensors. Further, in the above embodiment, the light emitted from the tester 2 is a simple pulsed light, but it can also be a code signal that is resistant to noise such as frequency modulation.

Since the detector of the present invention is configured and operates as described above, it is possible to obtain a fire detector equipped with a test device that can easily and accurately perform functional tests with the detector attached to the ceiling. be.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the fire detector of the present invention, FIG. 2 is a circuit diagram of FIG. 1, FIG. 3 is a circuit diagram of a tester, and FIG. 4 is a characteristic diagram. 2... Tester, 7... Light receiving element, 18... Amplifier, 19... Counter as a selection circuit, 20,
23, 25, 28...transistor, 21, 2
2, 24, 26, 27, 29...resistance.

Claims (1)

[Claims] 1 A light-receiving element that receives coded light emitted from a tester carried by the inspector and converts it into an electrical signal, a selection circuit that detects a predetermined signal output from the light-reception element, and a A fire detector equipped with a test device, characterized in that it is provided with means for changing the operating level of the detector.