JPS5812309Y2 - chikusekigatakasaikanchiki - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a storage type fire detector, and is particularly designed to stabilize its operation.

Generally, fire detectors are known in which a heat or smoke detecting section is driven in pulses in order to reduce power consumption.

This device has a short pulse width, and if the time constant of the storage circuit is made small for the storage type, it becomes susceptible to the effects of noise and the like, resulting in malfunction.

Furthermore, when the time constant is increased, the pulse width is short as described above, so there is a drawback that the time until the alarm is issued becomes longer.

The present invention eliminates the above-mentioned drawbacks by providing a pulse between a detector and an accumulator driven by the output pulse of the detector, which generates a pulse longer than the pulse width of the output pulse, and a pulse of the output pulse. An oscillator that recovers in a shorter time than the interval is provided, and the output of the oscillator is input to the storage circuit to obtain an accumulation type fire detector which is less affected by the noise and has a short time for alarm 1. This is how it was done.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a well-known ionization smoke detector with one radiation source and two chambers, which is composed of an external electrode 2, an intermediate electrode 3, an internal electrode 4, and a radiation source 5. An outer chamber is formed, and an inner chamber is formed by the intermediate electrode 3 and the inner electrode 4.

A constant voltage (2) is applied to the external electrode 2 and internal electrode 4 from a constant voltage power source 6, which will be described later.

When smoke enters the external chamber due to a fire, etc., the ion current from the radiation source 5 decreases, the voltage 1 between the external electrode 2 and the intermediate electrode 3 increases, and the voltage between the external electrode 2 and the internal electrode increases. Since the voltage V between the intermediate electrode 3 and the internal electrode 4 is constant, the voltage v2 between the intermediate electrode 3 and the internal electrode 4 becomes low and the FE
T1 turns on.

The oscillator 7 is connected to the source of this FET, and the FET□
The output becomes a pulse signal.

The ionization type smoke sensor 1, FET 1, and oscillator 7 constitute a detector 8 that detects smoke and outputs a pulse signal.

The constant voltage power supply 6 includes a capacitor 9 and a Zener diode 10, and supplies a constant voltage current to the ionization type smoke detector 1 and the oscillator 7 through a high resistance 12 from signal/feed lines 11a and 11b.

The output pulse signal from the detector 8 is as shown in FIG. 2A, and this pulse signal turns on the switching transistors 13 and 14.

An oscillator 15 is driven by the output pulse of the detector 8, generates a pulse longer than the pulse width of the output pulse, and returns in a shorter time than the pulse interval of the output pulse.

When the transistor 14 is turned on, its collector potential drops, and the gate potential drops below the anode potential of the first programmable unijunction transistor PUT1, turning PUTl on.

By turning on this PUT, the capacitor 1 is connected through the resistor 16.
7 is charged, and the anode potential of the second programmable unijunction transistor PUT2 reaches the resistor 18.1.
When the gate potential set in step 9 is reached, PUT2 is turned on.

When the PUT2 is turned on, the discharged charge of the capacitor 17 raises the cathode potential of the PUT higher than the anode potential through the capacitor 20, and the PUTl is turned off.

Therefore, the cathode potential of PUT□, ie, the output of the oscillator 15, becomes as shown in FIG. 2B.

The output of this oscillator 15 is connected to the capacitor 22 of the storage circuit 21.
is supplied through the resistor 23, and when the capacitor 22 is charged so that the anode potential of the third programmable unijunction transistor PUT3 reaches the gate potential divided by the resistor 24.25, PUT3 is turned on.

FIG. 2C shows the voltage of the capacitor 22, and when this reaches a predetermined value, the PUT is activated as shown in the second diagram.
The output of the resonator 21 is obtained at the cathode 3.

When the PUT 3 is turned on, the charge of the capacitor 22 flows to the base of the transistor 26.27 constituting the signal transmitter 28, the transistor 26.27 is turned on, and the signal/power supply lines 11a and 11b are short-circuited.

As shown in FIG. 3 or 4, the power supply current for the storage circuit 21 is supplied from the output of the oscillator 15 so that the storage circuit 21 consumes no power until the signal from the detector 8 is received. However, it can be implemented.

In this case, there is no current consumption by the oscillator applied to the stable side, and no current flows through the resistors 24 and 25, so power consumption can be extremely reduced.

In addition, as shown in Fig. 4, when FET2 is used in the storage circuit 21, the load 29 cannot be made smaller in size due to connection with the next stage, resulting in increased power consumption. Since the power consumption can be reduced by supplying the power supply current using the output of the oscillator 15, it is possible to prevent the number of fire detectors connected to the receiver from being limited as much as possible.

In FIGS. 3 and 4, the same reference numerals as in FIG. 1 indicate the same effect.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
3 and 4 are circuit diagrams showing other embodiments of the present invention. 8: Detector, 15: Oscillator, 21: Storage circuit, 28: Signal transmitter.

Claims (1)

[Scope of utility model registration request] A detector that detects that a physical quantity such as heat or smoke generated by a fire has changed by a predetermined value 1 and outputs a pulse signal, and a detector that is driven by the output pulse of the detector and has a longer pulse width. An oscillator that generates a pulse and returns to normal in a time shorter than the pulse interval of the output pulse, an accumulation circuit that accumulates the output of the oscillator, and a fire detection signal that sends out a fire detection signal when the output of the accumulation circuit reaches a predetermined value. A storage type fire detector characterized by being equipped with a signal transmitter.