CN103366495B - A kind of air suction type high sensitivity smoke particle detector and application thereof - Google Patents

A kind of air suction type high sensitivity smoke particle detector and application thereof Download PDF

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Publication number
CN103366495B
CN103366495B CN201310291204.0A CN201310291204A CN103366495B CN 103366495 B CN103366495 B CN 103366495B CN 201310291204 A CN201310291204 A CN 201310291204A CN 103366495 B CN103366495 B CN 103366495B
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smoke particle
detector
fire
measuring
suction type
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CN103366495A (en
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刘士兴
尹坤
陈长正
骆鑫鑫
任晓
鲁迎春
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Hefei University of Technology
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Hefei University of Technology
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Abstract

The invention discloses a kind of air suction type high sensitivity smoke particle detector and application thereof, it is characterized in that the end of smoke particle detector arrangement at the pump-line of area to be monitored, initiatively extracted and filtered air sample by pump-line, utilize detector to adopt laser particle scattering method to initiatively to extract and the smoke particle that in filtered air sample, particle diameter is not more than 20 μm detects.The present invention may detect atomic little smoke particle, and the extreme early that can occur at fire detects fire characteristic parameter effectively; Overcome the interference of passive wait time delay and the flowing of protected location air, eliminate the impact of smoke particle concentration dilution on detection accuracy; By the highly sensitive combined monitoring to smoke particle concentration, temperature and the CO gas three kinds of fire characteristic parameters in air sample, the deficiency of the single monitoring smoke particle of existing air suction type fire detecting system can be overcome, effectively reduce false alarm rate.

Description

A kind of air suction type high sensitivity smoke particle detector and application thereof
Technical field
The present invention relates to fire detector and detection method, more particularly especially a kind of be applied in the purity requirements high field such as communications equipment room, pulpit and chip manufacturing workshop a kind of extreme early fire detecting method.
Background technology
Detection is by some early stage characteristic parameters and the monitoring of phenomenon occurring fire, judging the generation of fire in time, exactly and send warning.For effectively suppressing the generation of fire, reducing the loss of disaster, in communications equipment room, pulpit and manufacture the clean room etc. of the chip place high to demand for security, requiring to carry out extreme early warning to fire.
Fire detection technology is measure the smokescope of fire and the physical characteristics of temperature in essence, and traditional sense cigarette, temperature-sensing fire detecting technology play an important role in detection, and perfect at development.Smoke particle, temperature and carbon monoxide are three key character parameters that fire occurs, and at the initial stage that fire occurs, comprise extremely early stage, due to the rough burning of comburant, have had appreciable CO gas to produce; The Pintsch process of comburant, can discharge smoke particle particle, and their appearance all wants Zao than flame and high temperature.Smoke detector technology is exactly the content by detecting smoke particle in air, provides fire early warning signal.And uncertain factor (dust, steam and thermal source etc.) all will have obvious impact to the detection of these parameters in different incendiary materials, burning condition and a lot of surrounding environment, seriously reduce the reliability that fire is judged of conventional fire detector, easily cause the wrong report of fire detector.
The point-type be widely used at present or line style sense cigarette, heat fire detector are passive working method, cannot overcome the impact of the unfavorable factors such as the thermal boundary effect above the small and room of smog thermal effect.And early stage at fire, the rate of propagation of cigarette is comparatively slow, will could arrive detector through certain hour; Meanwhile, because smog is constantly diluted in diffusion process, common smoke detector cannot meet the requirement of extreme early fire detecting and alarm compared with muting sensitivity.
Summary of the invention
The present invention is the weak point for avoiding existing for above-mentioned prior art, a kind of air suction type high sensitivity smoke particle detector and application thereof are provided, by carrying out highly sensitive accurate detection to smoke particle in early days, carly fruit drop can be carried out in conjunction with temperature and gas, overcome the deficiency of the single monitoring smoke particle of existing air suction type fire detecting system, effectively reduce false alarm rate.
The present invention is that technical solution problem adopts following technical scheme:
The feature of air suction type high sensitivity smoke particle detector of the present invention is: described smoke particle detector arrangement is at the end of the pump-line of area to be monitored, initiatively extracted and filtered air sample by pump-line, utilize described detector to adopt laser particle scattering method to initiatively to extract and the smoke particle that in filtered air sample, particle diameter is not more than 20 μm detects, obtain detection signal.
The feature of air suction type high sensitivity smoke particle detector of the present invention is also:
The infrared laser that the wavelength that described smoke particle detector sends using lasing light emitter is 850nm, power is 5mW is as measuring beam, and the direction of described measuring beam and the light-receiving direction of optical receiver be made up of photo-sensitive cell are all on mutually perpendicular axis with the air current flow direction imported by air admission hole; Described measuring beam is adjusted to a branch of directional light by beam expanding lens and collimating and correcting unit, be collected in and because the smoke particle that early stage and particle diameter that is that produce is not more than 20 μm occurs fire, ir scattering light produced for described measuring beam in detection cavity, described ir scattering light converges to photo-sensitive cell by condenser, forms the current detection signal with scattered light intensity linearly proportional relation in optical receiver; Immediately below detection cavity, be provided with delustring chamber, described delustring chamber is used for carrying out delustring process to measuring beam, and measuring beam is scattered also direct projection on the light absorbent in delustring chamber by the cone hit exactly bottom delustring chamber.
The vibrational power flow of described optical receiver is: described photo-sensitive cell adopts two ends without the silicon photocell of bias voltage, the position of detecting chamber symmetry is arranged two panels silicon photocell, exports the current detection signal with scattered light intensity linearly proportional relation by described silicon photocell.
Current detection signal for described silicon photocell arranges low noise amplifier circuit; Described low noise amplifier circuit adopts the optical pressure formula amplifying circuit adding phase compensation electric capacity, phase compensation electric capacity C fbe connected in parallel in the backfeed loop of described low noise amplifier circuit.
The feature of the highly sensitive fire detector of active inspiration formula of the present invention is: arrange an aspirating air pipe, filtering module is set gradually from the inlet end of described aspirating air pipe, temperature sensing module, CO gas detecting module and asepwirator pump, smoke particle detector is set at the endpiece of described asepwirator pump, imports filtered air sample with described asepwirator pump to described smoke particle detector; Arrange a data processing module, described data processing module carries out signal transacting and judgement for the detectable signal from described temperature sensing module, CO gas detecting module and smoke particle detector, realizes fire alarm.
The feature of the highly sensitive fire detector of active inspiration formula of the present invention is also: the described detectable signal from temperature sensing module, CO gas detecting module and smoke particle detector comprises: smoke particle concentration value s, smoke particle concentration added value ds, temperature value t, the continuous rising value dt of temperature, carbonomonoxide concentration value g, carbonomonoxide concentration increment dg.
Compared with the prior art, beneficial effect of the present invention is embodied in:
1, the present invention is by being arranged in the pump-line initiatively extracting air sample of area to be monitored, in detecting chamber, adopt laser particle scattering method to detect the smoke particle in air sample, effectively overcome the time delay of passive wait and the interference of protected location air flowing, eliminate the impact of smoke particle concentration dilution on detection accuracy; The situation of monitor area fire can be reflected truly;
2, in the present invention, the vibrational power flow of detector can ensure in air sample without in smoke particle situation, laser is absorbed by light absorbent through reflection repeatedly in delustring chamber, prevent laser reflection from returning the impact of measuring chamber on photo-sensitive cell, when guarantee enters and exists without smoke particle in the air sample of measuring chamber, laser can not be scattered, photo-sensitive cell does not receive scattered light, does not have scattered light signal to be received by the receiver;
3, the present invention utilizes detector to collect because the early stage a small amount of trickle smoke particle produced occurs fire, and produces ir scattering laser, and this scattered light converges to photoelectric sensor by condenser.Within the scope of finite concentration, smoke particle concentration in sample air is higher, stronger to the scattering power of laser, photoelectric sensor also will receive stronger scattered light signal, the current signal of the corresponding size of timely generation, its export electric signal and scattered light intensity linear, be greatly conducive to follow-up signal process;
4, the present invention arranges low noise amplifier circuit, and the system of ensure that can detect the microsize smoke particle of extremely low concentration in sample air.Adopt silicon photocell to detect the light signal of smoke particle scattering in detecting chamber, fundamentally eliminate the impact of dark current on signal at photoelectric cell two ends without the design of bias voltage.By arranging the laser of two panels photoelectric cell detection smoke particle particle scattering on the position of detecting chamber symmetry, reducing the noise of photoelectric switching circuit, enhancing the input of light signal, improve system sensitivity;
5, the present invention have employed the optical pressure formula amplifying circuit adding phase compensation electric capacity, phase compensation electric capacity C in low noise amplifier circuit fbe connected in parallel on backfeed loop.Phase compensation electric capacity C fintroducing, for amplifying circuit exists locate the phase margin of introducing limit and 45 °; Overcome the frequency f at noise gain and open-loop gain intersection 2the signal oscillating that may occur.
6, utilize air suction type high sensitivity smoke particle detector of the present invention, merge with the detection of temperature, gas further, overcome the deficiency of the single monitoring smoke particle of existing air suction type fire detecting system by Multi-information acquisition, effectively reduce false alarm rate.
Accompanying drawing explanation
Fig. 1 is air suction type of the present invention highly sensitive smoke particle concentration detection optical detection cell structure schematic diagram;
Fig. 2 the present invention adds the amplifying circuit schematic diagram of phase compensation electric capacity;
Fig. 3 the present invention forms active inspiration formula highly sensitive complex parameter fire detecting system structural representation;
Fig. 4 the present invention forms active inspiration formula highly sensitive complex parameter detection main machine structure schematic diagram;
Number in the figure: 1 lasing light emitter, 2 beam expanding lenss, 3 collimating and correcting unit, 4 extenal fixation frameworks, 5 detection cavities, 6 photo-sensitive cells, 7 ventholes, 8 cones, 9 delustring chambeies, 10 signal processing circuits, 11 condensers, 12 air admission holes, 13 system hosts, 14 communication interfaces, 15 aspirating air pipes, 16 filtering modules, 17 temperature sensing modules, 18 CO gas detecting modules, 19 asepwirator pumps, 20 signal processing modules, 21 smoke particle detectors, 22 discharge duct outlets.
Embodiment
In the present embodiment, the vibrational power flow of air suction type high sensitivity smoke particle detector is: by the pump-line end of smoke particle detector arrangement in area to be monitored, initiatively extracted and filtered air sample by pump-line, utilize detector to adopt laser particle scattering method to initiatively to extract and the smoke particle that in filtered air sample, particle diameter is not more than 20 μm detects, obtain detection signal.At the extreme early of fire and early stage, the particle diameter major part of smoke particle particle concentrates on about 1 μm, the present embodiment is for air sample filtering bulky grain, because entering detector at bulky grain, the more energy of meeting forescatering, affect the related coefficient between probe value and smoke particle concentration value, interference is caused to the result of detection of smoke particle concentration.
See Fig. 1, the infrared laser that the wavelength that in the present embodiment, smoke particle detector sends using lasing light emitter 1 is 850nm, power is 5mW is as measuring beam, and the direction of measuring beam and the light-receiving direction of optical receiver be made up of photo-sensitive cell 6 are all on mutually perpendicular axis with the air current flow direction imported by air admission hole 12; Measuring beam is adjusted to a branch of directional light by beam expanding lens 2 and collimating and correcting unit 3, be collected in and because the smoke particle that early stage and particle diameter that is that produce is not more than 20 μm occurs fire, ir scattering light produced for measuring beam in detection cavity 5, ir scattering light converges to photo-sensitive cell 6 by condenser 11, forms the current detection signal with scattered light intensity linearly proportional relation in optical receiver; Immediately below detection cavity 5, be provided with delustring chamber 9, delustring chamber 9 is for carrying out delustring process to measuring beam, and bottom delustring chamber 9, measuring beam is scattered also direct projection on the light absorbent in delustring chamber by the cone 8 of center.The relation that a certain size particle is inversely proportional to the scattering power of light and the biquadratic of wavelength, for the smoke particle particle of 0.001-20 μm, the green laser greatly about 550nm wavelength will be optimum selection.But the light source of green laser is by high-power infrared light and laser diode-pumped generation, its conversion efficiency is lower, also the work of lasting stability is unfavorable for, in order to ensure the stable of system, the present embodiment adopt wavelength be 850nm, power be the infrared laser of the infrared laser of 5mW as light source, described light source is produced by infra-red laser diode, low in energy consumption, stable performance.
As depicted in figs. 1 and 2, in the present embodiment, the vibrational power flow of optical receiver is: photo-sensitive cell 6 adopts two ends without the silicon photocell of bias voltage, the position of detecting chamber 5 symmetry is arranged two panels silicon photocell, exports the current detection signal with scattered light intensity linearly proportional relation by silicon photocell.
Fig. 2 illustrates, the current detection signal for described silicon photocell arranges low noise amplifier circuit; Described low noise amplifier circuit adopts the optical pressure formula amplifying circuit adding phase compensation electric capacity, phase compensation electric capacity C fbe connected in parallel on backfeed loop.
Phase compensation electric capacity C ffor: the signal amplification circuit of smoke particle concentration detection, based on the design of optical pressure formula measuring method, because photoelectric cell is without bias voltage, eliminates the impact of dark current noise on signal, faint photosignal also can be detected; The voltage that circuit exports and intensity of illumination are linear relations.In accuracy, owing to needing to amplify faint useful signal, the performance of amplifier is had higher requirement.Select bias current to be not more than 10pA, offset voltage is not more than 20 μ V, and voltage noise density is cmos amplifier be applicable to photoelectric conversion amplifier.(this part is finely tuned)
Low noise amplifier circuit shown in Fig. 2 has negative feedback, its phase compensation electric capacity C fbe connected in parallel on backfeed loop, realize the compensation of phase differential thus, strengthen amplifying circuit stability, effectively reduce noise gain.
Due to amplifying circuit input equivalent capacity C iexistence, there is a zero frequency f in amplifying circuit 1, equivalent capacity C fequiva lent impedance Z f=R f// (1/sC f), amplifying circuit is existed locate the phase margin of introducing limit and 45 °; Overcome the frequency f at noise gain and open-loop gain intersection thus 2the signal oscillating that may occur, wherein f ufor the unit gain frequency of amplifying circuit; Phase compensation electric capacity C f, value is 1-4.7pF.
See Fig. 3 and Fig. 4, in the present embodiment, smoke particle detector is applied to the highly sensitive fire detector of active inspiration formula, construction system main frame 13, its version is: arrange an aspirating air pipe 15, the inlet end of Self inhaling pipeline 15 sets gradually filtering module 16, temperature sensing module 17, CO gas detecting module 18 and asepwirator pump 19, at the endpiece of asepwirator pump 19, smoke particle detector 21 is set, flue gas is discharged in discharge duct outlets 22, imports filtered air sample with asepwirator pump 19 to smoke particle detector; One data processing module 20 is set, data processing module 20 carries out signal transacting and judgement for the detectable signal from temperature sensing module 17, CO gas detecting module 18 and smoke particle detector 21, realize fire alarm, can and by with communication interface 14 by data syn-chronization to other network-termination device.
The big dust particle being greater than 20 μm is utilized in filtering module 16 filtering air sample in the present embodiment, reduce smoke particle particle to a great extent in aspiration pump, pile up work efficiency on pump and the impact in serviceable life, alleviate smoke particle and sniffer inside is polluted.Reduce the error that bulky grain produces the detection of smoke particle concentration, reduce rate of false alarm.
Concrete enforcement is that the sampled point on the pipe network by being distributed in whole surveyed area carries out air sampling, and mixing is accumulated by the fire characteristic amount in the sample air collected, and exports detectable signal by the highly sensitive fire detector of active inspiration formula.Adopt highly sensitive and the detector of multi-point sampling effectively can solve smoke particle, CO gas in flow expansion process, dilute impact on warning accuracy.
In concrete enforcement, detectable signal comprises: smoke particle concentration value s, smoke particle concentration added value ds, temperature value t, the continuous rising value dt of temperature, carbonomonoxide concentration value g, carbonomonoxide concentration increment dg.
Judgment mode is exemplified below:
When carbon monoxide be concentration value g is 0, can judge that when any one meets in following condition fire occurs: condition 1:ds>5 and dt>3;
Condition 2:ds>10;
Condition 3:t >=temperature threshold 42 DEG C;
Condition 4:s >=smoke particle concentration threshold (40%).
Condition 1 is for naked light, and because the smoke particle of naked light is less, photoelectric detection unit is not too responsive to this, but naked light can cause temperature to have obvious rising, therefore rises in temperature, and then can think likely breaking out of fire when having a small amount of smoke particle.Condition 2 is for early stage smoldering fire, when detect smoke particle have significantly rise time, just think breaking out of fire; Condition 3 and condition 4 adopt threshold decision algorithm, and temperature threshold is set to 42 DEG C, and smoke particle threshold value is set to 40%.
The condition of carbon monoxide exception be following thrin:
Condition 1: carbonomonoxide concentration value g>50;
Condition 2: carbonomonoxide concentration increment dg>50;
Condition 3: carbonomonoxide concentration increment dg>10, and temperature increment dt>1.

Claims (3)

1. an air suction type high sensitivity smoke particle detector, it is characterized in that: described smoke particle detector arrangement is at the end of the pump-line of area to be monitored, initiatively extracted and filtered air sample by pump-line, utilize described detector to adopt laser particle scattering method to initiatively to extract and the smoke particle that in filtered air sample, particle diameter is not more than 20 μm detects, obtain detection signal;
Described smoke particle detector using the wavelength that lasing light emitter (1) sends be 850nm, power be the infrared laser of 5mW as measuring beam, the direction of described measuring beam and the light-receiving direction of optical receiver be made up of photo-sensitive cell (6) are all on mutually perpendicular axis with the air current flow direction imported by air admission hole (12); Described measuring beam is adjusted to a branch of directional light by beam expanding lens (2) and collimating and correcting unit (3), be collected in and because the smoke particle that early stage and particle diameter that is that produce is not more than 20 μm occurs fire, ir scattering light produced for described measuring beam in detection cavity (5), described ir scattering light converges to photo-sensitive cell (6) by condenser (11), forms the current detection signal with scattered light intensity linearly proportional relation in optical receiver; Delustring chamber (9) is provided with immediately below detection cavity (5), described delustring chamber (9) is for carrying out delustring process to measuring beam, and measuring beam is scattered also direct projection on the light absorbent in delustring chamber by the cone (8) of center, delustring chamber (9) bottom.
2. air suction type high sensitivity smoke particle detector according to claim 1, it is characterized in that: the vibrational power flow of described optical receiver is: described photo-sensitive cell (6) adopts two ends without the silicon photocell of bias voltage, two panels silicon photocell is arranged in the position that detection cavity (5) is symmetrical, exports the current detection signal with scattered light intensity linearly proportional relation by described silicon photocell.
3. air suction type high sensitivity smoke particle detector according to claim 2, is characterized in that: the current detection signal for described silicon photocell arranges low noise amplifier circuit; Described low noise amplifier circuit adopts the optical pressure formula amplifying circuit adding phase compensation electric capacity, and phase compensation electric capacity Cf is connected in parallel in the backfeed loop of described low noise amplifier circuit.
CN201310291204.0A 2013-07-11 2013-07-11 A kind of air suction type high sensitivity smoke particle detector and application thereof Active CN103366495B (en)

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