Working principle of the smoke detector

A smoke alarm, how does it work?

The smoke is rising motion, reach the ceiling. Smoke alarm through the smoke detection fire. When you have not see the flames or smell the smoke, the smoke sensor already know. It does not work, 365 days a year, 24 hours a day,uninterrupted. In alarm, it sends squealing shrill voice, until the smoke clears. In a realfire has been working to be burned.

Independent type smoke sensor alarm civilian housing a total of two kinds of sensorsare available: one is the ion sensor, a photoelectric sensor.

Ion sensor works is by measuring the charge air in the balance. In the sensor, a small piece of radioactive substances, such substances can produce a tiny electrical current in the induction of indoor air. On the circuit board, a computer chip to monitorthese currents. When the smoke particles into the sensing chamber, it will disturb thebalance of positive and negative charges there, at the same time that the current changes. When the smoke gradually increased, the imbalance will be positive and negative charges to strengthen. When this balance reaches a certain limit, the hornwill sound.

The photoelectric sensor to measure the concentration of smoke through the inductoris a beam of light and a light. When the device design, the beam is deviated from thesensor. When the smoke into the sensing chamber, the smoke particles will be part of the beam scattering the sensor. When the smoke concentration gradually increased,there will be more of the beam is scattered by the sensor. When reaching the sensorbeam to a certain degree, the buzzer will ring.

Two, how to reduce the false alarm?

The false alarm is a very serious problem. When the fire did not occur, the smoke alarm is constantly alert, you may take it out of the way, then when the fire happenedwill not sound the alarm.

The causes of false positives, the sequence is as follows: 1 the effect of cooking; 2vapor or moisture 3; cigarette smoke; 4 power; the 5 dust.

1 many of the cooking smoke alarm is sent out by the ion alarm. Because of this kind of sensor is sensitive to smoke particles of extremely small, even for the human eyecan not see the particle. Smoke particles and cooking at high temperatures is caused by people´s eyes can´t see.

There are two basic types of solutions. Mobile alarm position. An alarm will be installed in the place far away from cooking at the cooking generated smoke upon reaching thealarm has become very thin, so as to reduce false positives. But this method does notalways work, especially when the air flow will be cooking smoke to alarm when also can produce false positives. So when the mobile alarm must first make clear the airflow.

Second ways of solving the problem is to replace the alarm: A. is to buy a new onewith a mute button ion alarm. Just press the button alarm will stop the alarm for 15 minutes, this will there be enough time for cooking smoke diffusion. The B. option is to buy a photoelectric smoke alarm. Photoelectric alarm is less sensitive to tiny particles of smoke, so the smoke particles do not cook to generate error report.

2 steam or moisture will condense in the sensor and the circuit board, if theconcentration of too much moisture it will send out alarm sound.

Solution: the alarm device is installed in the steam and moisture from distant places,such as the bathroom hallway should not install the alarm, so that you can solve the problem. However, if the alarm could work normally, but the vapor or moistureresponse, then the problem may be the reason for alarm aging. Alarm older will become more sensitive and easier to response to steam and moisture occurs. So thefalse positives may also be alarm over the life needs to be replaced.

3 in general, smoke alarm is not on the cigarette smoke issued a response, unlessvery thick smoke, for example, many smokers are in the same room smoking can cause alarm. If the alarm is too old, even if the smoke concentration is very low, willresponse. So instead, we can judge whether the alarm has been aging.

The 4 battery when about to run about every minutes will also send out chirp voice(different models in the interval and the sound will be different, but have the power shortage warning function), some people will think that this is a false alarm.

But the sound is very different, because it is issued by a single, short sound, andabout once a minute will make a sound like this. If your alarm is intermittent sound,you can replace the battery to see whether they can solve the problem.

5 if the alarm continuously emit alarm sound, then it is likely that the alarm has accumulated in the dust too much, should consider replacing the alarm or to clean.When cleaning the alarm, the end of vacuum cleaner dust around near the alarmopening one by one. This product in the alarm of the dust can be completely removed.

Three, the use of smoke alarms effectively?

As the smoke alarm users continue to increase, residential fire deaths are declining.American National Fire Protection Association reports that the number ofrecommended, install smoke alarms in the house in case of fire, the house staffescape opportunities than not installed houses more than 50%.

Four, I smoke alarms may need to be replaced?