The key principle explanation of smoke detector

Smoke detectors have brought us great help in our lives. Let's explain in detail today where the principle of smoke detectors is embodied.

The smoke detector mainly realizes fire prevention by monitoring the concentration of smoke. The smoke detector uses ion smoke sensor inside. The ion smoke sensor is a kind of advanced technology and stable and reliable sensor. It is widely used in various In the fire alarm system, the performance is far superior to gas-resistance fire alarms.

The smoke detector has a radioactive source 241 in the inner and outer ionization chambers, and the positive and negative ions generated by the ionization move to the positive and negative electrodes respectively under the action of the electric field. Under normal conditions, the current and voltage of the internal and external ionization chambers are stable. Once there is smoke, escape the ionization chamber. Interfering with the normal motion of the charged particles, the current and voltage will change, destroying the balance between the inside and outside ionization chambers, so the wireless transmitter sends a wireless alarm signal to inform the remote receiving host to pass the alarm information out.

Smoke detector protection area

The protection area of ​​the smoke detector is determined by the height: when the space height is 6m~12m, the protection area of ​​a detector is 80m2 for general protection places. When the space height is 6m or less, the protection area is 60 square meters. The specific parameters shall be based on the "Code for the Design of Automatic Fire Alarm Systems" (GB 50116).

In "Automatic Fire Alarm Specification", we can find the correct answer about the protection area and protection radius of smoke detectors. From the figure below, we can clearly know the protection area and the protection radius of the smoke detector, as well as the number of detectors that need to be set in a detection area.

The installation distance of the smoke detectors and temperature detectors shall be determined according to the protection of the detectors to the product A and the protection radius R, and shall not exceed the limit curve D1-D of the installation spacing of the detectors in Appendix A of this specification. 11 (including D9').

The number of detectors to be set in a detection area should not be less than the calculated value of the following formula:

NS/K.4

In the formula, N - the number of detectors (only), N should be an integer

S - the detector area area product (m2);

A—Probe protection area (m2);

K - correction factor, special protection object should take 0.7-0.8;

The primary protection target should be 0.8-0.9, and the secondary protection target should be 0.9-10.

In a word, smoke detectors are still common in life, which brings us a lot of convenient places for our lives. It plays a very good role in safeguarding our safety and allows us to perfect our process.