CN2079752U - Smoke sensory detector by ionization particle - Google Patents

Abstract

The utility model discloses a smoke sensory detector by ionization particle, comprising a micropower high-pressure inverter, a detecting ionization chamber, a contrasting ionization chamber, a voltage comparator, an electronic switch, an acousto-optic display, etc. The utility model adopts the micropower high-pressure ionized air as the particle source, and uses the high-pressure source as the signal input source of the smoke sensory detector by ionization particle, and therefore, the sensitivity is very high. The main is that the utility model overcomes that the like product brings the pollution to the environment for using the radiation nature. The utility model has the advantages of easy production, low cost, easy popularization and easy use. The two ionization chambers are synchronously changed when the conditions such as the air-pressure, etc. are changed, which overcomes the false action.

Description

Smoke sensory detector by ionization particle

The utility model relates to a kind of particle smoke detector, particularly a kind of ionizing particle smoke detector.

Existing particle smoke detector, as headquarter of Chinese People's Armed Police Force, and " the 390th page of " FJ-2700 series ionic smoke sensor formula automatic fire alarm system " of being introduced of security personnel's equipment handbook commonly used that China People Armed Police Forces Technology College edited, and the 397th page of " FJ-2701 type ionic smoke sensor formula detector of being introduced; be to advance the air-flowing type ionization chamber of cigarette and compensated ionization chamber that cigarette is not easy to enter polyphone, in ionization chamber, lay two isotopes with one ²⁴¹Am makes its room air ionization as radioactive source, adds 24 volts of DC voltage at the ionization chamber two ends of this polyphone.When fire takes place, after smog enters and detects ionization chamber, ionization charge migration speed is reduced, so ionization current reduce, the equiva lent impedance that detects ionization chamber increases, and the compensated chamber is because of smokelessly entering, the ionization chamber impedance remains unchanged.Therefore, cause the variation of ionization chamber intrinsic standoff ratio, make the ON-OFF control circuit action that is mated, send alerting signal.But this particle smoke detector.Owing to used the radioactive isotope americium ²⁴¹Am produces particle source, this just is subjected to radioactive contamination to environment and the room air of installing and using this detector unavoidably, this detector is installed in skyscraper mostly, on the ceiling as room, various hotel, and the floor of common skyscraper is all very short, this is just almost as on head, particularly all once there was report analysis to mention both at home and abroad, employed material americium, be a kind of americium book in fact, the piece of falling phenomenon is arranged, people are frightened can be because of dropping in the Food ﹠ Drink cup, thereby entering human body works the mischief, and for general manufacturer, the americium raw material is difficult for obtaining, and working condition is difficult to possess, the particle smoke detector can not generally be produced extensively promote the use of, production cost is high.

The purpose that this practicality is new is exactly the weakness at existing product, and a kind of ionizing particle smoke detector is provided, and it does not use americium ²⁴¹Am makes particle source, is used as particle source but the high voltage that adopts an inverter to export causes air ionization, thereby has avoided the pollution problem of using radioactive isotope to bring, and be convenient to common production, and cost is low, can extensively promote the use of.

Realize the ionizing particle smoke detector that solution provided of the purpose of this utility model, it is by inverter, have the detection ionization chamber of opening window and contrast ionization chamber, the voltage comparator of weak sealing, electronic switch and acousto-optic display element are formed.It is the finished product of LFC5 that its voltage comparator is selected a model for use.Its inverter is by an ic chip ₁, resistance R ₀And feedback condenser C ₁Form an oscillator, the output terminal of oscillator and step-up transformer B ₁Elementary linking, the secondary high-voltage alternating that then generates of transformer is through commutation diode BG ₁Rectification obtains high voltage, finishes the positive high voltage output of inverter.Its sound and light show circuit is by a siren and light emitting diode LED And connection, link with the output terminal of electronic switch, and the duty of klaxon and light emitting diode is controlled by electronic switch, as shown in drawings.

The positive pole of above-mentioned detection ionization chamber and contrast ionization chamber is to be made of a thin metal pipe, and they are through shunt resistance R ₁, R ₂Be connected by (as accompanying drawing) with the high pressure positive output end of inverter, the negative pole of these two ionization chambers is made of a superfine tinsel, and the negative pole of two ionization chambers all passes through current-limiting resistance R ₅, R ₆Link with two input ends of comparer,, can not be coated with other conductive materials, also can be coated with other conductive materials, for example conductive material that other work functions such as thoria are lower or the like as the surface wiry of ionization chamber negative pole.The negative pole of two ionization chambers is to being connected to stabilivolt W between the zero line ₁, W ₂Than the protective effect of the device input utmost point, connecting two stabilivolt W as a comparison ₁And W ₂The place, also and be connected with resistance R ₃, R ₄With the quiescent imput voltage of balance comparer, at two ionization chamber negative poles each other, connect one and merely hit and resistance R ₇, in order to demarcate detector sensitivity.Symbol ※ represents that the resistance of resistance in the production debug process, need adjust transposing.Output terminal at comparer is connected to electronic switch, electronic switch guide sound optical display unit.

When the moment of detector energising, the particle concentration of two ionization chambers has just reached equilibrium state in the time of Millisecond.In fact＞0.4 centimetre approximately of the migration velocity of ion, every volt per second small-particle ², middle particle approximates 0.07 centimetre ²,＜0.001 centimetre approximately of macroparticle ²When fire takes place, smog enters the detection ionization chamber, two ionization chambers originally all have only little ionizing particle, because of the carbon black in the smog and water smoke all are the particles that belongs to very big, the migration velocity that detects the ionization chamber electric charge is reduced, therefore ionization current reduces, the equiva lent impedance that detects ionization chamber increases, and the voltage comparator reverse inter-input-ing voltage descends, and the contrast ionization chamber does not also have smog to enter, the remain unchanged in-phase input end of voltage comparator of ionization chamber impedance still remains on noble potential, this moment, comparator output terminal then had output, and the power supply that the breakdown electronic switch is connected sound and light display shows, has so finished the detection mission that perception smog takes place.Because as the high-voltage power supply that produces particle source, also be the input signal source of comparer simultaneously, so detector sensitivity is very high.If when condition changings such as air pressure, then the variation of two ionization chambers is to be in synchronous change basically, then can overcome the generation of misoperation.

Claims (3)

1, use is at fire alarm particularly in the fire alarm, the ionizing particle smoke detector, this detector has a detection ionization chamber and a comparison ionization chamber, the all common positive output end with an inverter of the positive pole of these two ionization chambers links, detect the negative pole and the negative pole that compares ionization chamber of ionization chamber, common inverting input and in-phase input end with a voltage comparator links respectively, the output terminal of voltage comparator and an electronic switch link, the power supply of electronic switch control sound and light show circuit, and making system play the effect that smoke detection is reported to the police, feature of the present utility model is the detection ionization chamber of this detector and compares ionization chamber and all insert high-voltage DC power supply.

2, detector according to claim 1, the positive pole that it is characterized in that two ionization chambers is to constitute with thin metal pipe.

3, detector according to claim 1, the negative pole that it is characterized in that two ionization chambers is to constitute with fine wire.

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