The composition and advantages of ionic smoke sensing
When the smoke particles enter the ionization chamber, the diameter of the smoke particles is much larger than the diameter of the ionized air particles. Therefore, the double role of smoke particles in ion trapping and trapping of ions in the ionization chamber results in the reduction of ion flow. Figure 1-2 shows, ion smoke detector has two ionization chamber, a smoke particle can freely enter the ionization chamber (measuring chamber), another is not the smoke into the ionization chamber (equilibrium ionization chamber), two chamber and series voltage at both ends under normal conditions, V = V1 +V2. When the smoke particles into the ionization chamber when the ion flow decreased two ionization chamber voltage redistribution, V1 becomes V11, V2 becomes V22, when V11 < V1, V22 < V2, the potential 2 nodes to the change of the output signal of fire alarm.
The ion smoke smoke detector detects fire by using the variation of the ion flow in the ionization chamber, which is proportional to the concentration of smoke entering the ionization chamber. The radioactive source ionization chamber (radioactive elements: "am 241") of the pure air ionization chamber, the formation of positive and negative ions. When a voltage is added between the two collector plates, an electric field is formed between the plates. Under the action of the electric field, the ions move toward the positive and negative plates respectively to form an ionic current.
