Smoke detector

In the modern urban family,the fire accidents happened due to the lack of home safety knowledge.fire alarm destroy happy families in Blink of an eye,and if handle improperly or alarm delay,the fire accidents will lead to family broken up and decimated.so mastering the basic knowledge of fire accidents and how to protecting from fire is rather important in modern life.

There are more than 50000 serious home fire accidents happened every year in U.K,Most fire accidents caused significant casualties and property losses,and some hurt the neighbors,When investgating the reason of fire accident, persons involved or implicated said they feel fire accident is far away from their family,so they don’t treasure it. preventive measures for fire accident is necessary.

1,introduction of smoke detector:

Smoke detector,also called smoke sensors mainly used fire-extinguishing system and Building security system.It adopt a photoelectric sensor with special structure,SMD chip process production,the feature of smoke detector is high sensitivity,stability, reliability,Low power consumption,easy to use etc.The circuit and power supply can be self-tested and also can be simulated tested.

2,categories of smoke detector:

Ionic smoke detector is a kind of Point-type detector,It is a small amount of ionizing in the ionization room,which can make the indoor air to become conductors, allow a certain current pass between two electrodes through the air,and ionizing radiation enable parts air area to be ionization state,formed to ion current via the help of voltage,which let ioniztion chamber with the function of effective conductivity.When smoke particles enter the ionization area,they dovetail with the ion to reduce the conductivity of air,then the ion movement become weak.When the conductivity falls below a predetermined value,smoke detector will give alarm.

Photoelectric smoke detector use the feature of smoke which is formed by fire can change propagation of light to work.Photoelectric smoke detector can divided into dark type and astigmatism type according to feature that smoke particles can absorb and scatter light.

Infrared beam smoke detector is a kind of linear detector,it detects the smoke parameters of a narrow range in protection area.The main difference from Point-type detector is that it divided into two independent parts: beam Transmitter and beam receiver,This two parts installed into two different places,using beams to connect. Infrared beam smoke detector often installed on the places where is easy to catch fire,not suitable the place where is often full of smoke, or ventilation premises.

3.principle of work.

Now the most common smoke detector are photoelectric smoke detectors and Ionic smoke detectors. There is a a light sensor in Internal structure of photoelectric smoke detectors,When light sensor senses the absence of light,the alarm will trigger,so if the smoke thick enough to block the light,the smoke detector will trigger and give alarm.

The appearance of photoelectric smoke detector is usually a little large,and not so sensitive.The alarm goes only when the smoke is heavy enough to completely block the light.Therefore,the photoelectric smoke detector adopts different approaches to use light,Inside smoke detector,there is a light source and a light sensor,which installed to a 90 degree angle,under normal circumstances,the light from left side light souce will go out directly not pass through light sensor,only when smoke plunge into chamber,the smoke particles would spread out the light, some light will reach on sensors, and sensor will activate the siren of smoke detector to give a alarm. photoelectric smoke detector is more suitable for fire accident with heavy smoke,such as mats smoldering.

4,Installation

Smoke detector is suitable for Home,shop,dance hall,hospital,supermarket,warehouse，and other places of the fire alarm.The process of fire is usually start with smoke,heat,light.In the begaining,as the temperature is too low,the material is in smoldering stage creating a large of smoke,smoke is an important feature of early fire,smoke type fire detector developed according to this feature.It’s a kind of device which convert the Smoke concentration of detected area to an electrical signal to achieve alarm.