KR800000907Y1 - End gate type smoke senser - Google Patents

Abstract

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Description

AND GATE Smoke Detector

1 is a block diagram of the present invention.

2 is an overall circuit diagram of the present invention.

3 is a principle diagram of the heat sensor of FIG.

4 is a principle diagram of the smoke detector of FIG.

The present invention is to prevent the frequent misinformation of the smoke detector and relates to a smoke detector that combines the heat rising condition with the AND GATE method inherent in the smoke detector.

Conventional ion or photoelectric smoke detectors have the advantage of detecting fires faster than heat detectors using bimetallic or air-expansion in air pipes because they detect smoke and generate fire. However, there are frequent disadvantages due to dust, exhaust gas, water vapor, etc.

In order to eliminate the disadvantage that the smoke detector's normal fire detection operation is consequently misleading due to environmental conditions other than the fire, the present inventors pay attention to the difference between the smoke generated at the time of fire and the normal smoke caused by cigarette smoking or dust. The difference between fire smoke and non-smoke smoke is combined with the AND GATE of the smoke detector's operating conditions to prevent false fire alarms caused by environmental conditions.

Experimental data on fire shows that smoke in a fire has a temperature of at least 50 degrees Celsius within 200m and its temperature increases with time. When combined, smoke detectors operate only when heat and smoke are present at the same time, and alarm when smoke is present or only when heat is present. The circuit shown in FIG. 1 is a block diagram, where 1 is a smoke detector, 2 is a heat detector, and 3 is an AND gate.

In such a known circuit, the AND gate 3 operates only when there is an output from the smoke detector 1 and the heat detector 2 at the same time, and outputs it to the AND gate 3, and the smoke detector 1 and If either of the heat detectors 2 has an output or both have no output, it will not operate.

Therefore, as shown in FIG. 2, the heat sensor 2 'detects a lower temperature such as 20 ° C-100 ° C than the nominal operating temperature of the independent heat sensor (70 ° C-150 ° C). The small, semiconductor sensing element allows the construction of a temperature sensing unit, greatly reducing heat detection time. The basic principles of the thermal and smoke detectors of such a circuit are simply shown in FIGS. 3 and 4.

The basic circuit of FIG. 3 is the principle diagram of the thermal sensor 2 'of FIG. 2, and since the resistance of the thermistor TH is usually in a very high state, the voltage at the connection point T ₁ is directly divided by the resistor R ₅ . The resistance R _{2 of} FIG. ₂ is not biased since it is very low.

However, when a fire occurs and the temperature of the thermistor TH rises due to the heat flow, the resistance is drastically lowered, thereby increasing the voltage at the connection point T ₁ and supplying a bias voltage to the resistor R ₂ of FIG. ₂ .

The main circuit of FIG. 4 is the principle diagram of the smoke detector 1 'of FIG. 2, and when the smoke entry box CH does not contain smoke, the field effect transistor FET does not operate, and thus the voltage of the resistor R ₆ is reduced. And the bias voltage is not applied to the resistor R _{1 of} FIG. _{2 which} is connected to the connection point T ₂ . However, when a fire occurs and smoke enters the smoke entry box CH, the field effect transistor FET is operated and as a result, a voltage is applied to the connection point T ₂ to supply a bias voltage.

The field effect transistor FET operates when the reverse bias of the field effect transistor FET is normally blocked.

The smoke detector 1 'and the heat detector 2' operate simultaneously, and at their outputs, the bias resistors R ₁ and R ₂ are subjected to a "+" voltage, and the transistors Q ₁ and Q ₂ are saturated. As it is operated and conducting, the output voltage is applied to the resistor (R ₃ ). This output voltage conducts SCR and the alarm relay Ry is operated by the conduction current, which is connected to the alarm circuit at the contact point P and the contact point Q Alarm the fire.

The normal fire monitoring current of the smoke detector 1 'and the heat detector 2' is supplied through the alarm relay Ry, but the alarm relay Ry is operated normally because it is far below the operating current of the alarm relay Ry. It supplies only the holding current necessary for fire monitoring. However, when the smoke detector 1 'and the heat detector 2' operate simultaneously and the AND gate circuit 3 'operates and the SCR of the output circuit 4' operates, the alarm relay Ry operates. Alarmed.

Drawings, reference numeral R ₄ is a current regulating resistor, and 4 of the light-emitting diode LED of the "a receiver 7 'is a non-polar circuitry to operate without any problem even when the circuit is 6, the terminal AB of the power supply voltage V is connected the other hand D ₁ , D ₂ , D ₃ and D ₄ are current direction adjustment diodes.

Claims (1)

As shown in FIG. 2, the output is composed of a known smoke detector 1 'and a heat detector 2', and each output is composed of an AND gate with transistors Q ₁ and Q ₂ . Smoke detector.