CN1003099B

CN1003099B - Particle detector for detecting conflagration

Info

Publication number: CN1003099B
Application number: CN85103159A
Authority: CN
Inventors: 卢斯·安德莱; 丢特却-拉丢里-丹尼尔; 高尔德曼·麦克斯; 高尔德曼·艾丽丝
Original assignee: BUHEWAY Ltd
Current assignee: BUHEWAY Ltd
Priority date: 1985-04-24
Filing date: 1985-04-24
Publication date: 1989-01-18
Also published as: CN85103159A

Abstract

The present invention relates to a detector (1) which is provided with a working point near a Townsed discharge region. When ions are trapped, the electric current passing through a sensor is increased. An electrode of the sensor is formed by conducting wires folded in an alpha shape.

Description

The particle electric detector of detection of fires

The present invention relates to a kind of particle electric detector, be used for monitoring the air in certain place, be specially adapted to detection of fires.

Utilize ion detection to come detection of fires, this is that everybody is very familiar.Usually, cause room air ionization with a kind of radioactive source or periodicity electric spark, and, survey by salt, measure the electric current of ionization.When catching fire, some heavy smoke particles of the site of an accident propagate into detecting chamber always, in detecting chamber since capture or filling some heavy smoke particles, and disturbed flowing of ion.In this case, the ionization current of measuring has just reduced, and just can send alerting signal this moment.Have to be noted that temperature can make ionization current reduce too.Get angry alert * for fear of missing because of humidity effect, generally all settle one not temperature influence with reference to the chamber, not so, just detector sensitivity is carried out electronic compensation.In this case, surveying the fire of hiding suffers from just very difficult.In fact, because these fire are not emitted a large amount of heat, the convection current of air also is not enough in reasonable time heavy particle is sent in the detector.Therefore, the response time that detector is suffered from sleeper fire is very long, and this just is unfavorable for observing security regulations.

One of purpose of the present invention is exactly to make a kind of detector, and this detector is opposite with the detector that everybody is familiar with just, when it just takes place at fire, increases owing to the electric current by detector appears making in particle.

Another object of the present invention provides a kind of very simple charged particle detector, and it can use dissimilar power supplys, and power consumption is also especially little.

Content of the present invention is a particle electric detector with dual-electrode sensor, and the sensor voltage fed is characterized in that, the sensor current work point is in 10 ^-13With 10 ^-19Between the ampere (A), another feature is that the ion of being captured by the sensor can cause that the electric current by detector increases.

According to other characteristics of the present invention.

-electrode is that the lead that is used to be folded into α shape makes;

An electrode of-sensor is connected with power supply by the very high resistance of resistance, and another electrode then links to each other with measurement point, and passes through a resistance eutral grounding from there;

-when sensor was powered, trapping ion will cause the increase of electric current in the sensor;

The power supply of-sensor is at least by a diode that is operated in characteristic district initial segment, and diode also plays a resistance effect;

-sensor links to each other with measurement point by a high resistance measurement, and each end of this resistance is all with the very little capacity earth of capacity;

-the lead that makes α shape electrode all has an a little shape prickle.

As an example, we are described on accompanying drawing:

Fig. 1 presses the simple circuit synoptic diagram of a kind of embodiment of charged particle detector of the present invention;

Fig. 2 is to Figure 11, the various electrode embodiment of the sort of detector of Fig. 1;

Figure 12, a kind of different embodiments of Fig. 1 circuit diagram;

Figure 13 is according to the enlarged drawing of the α shape electrode of Fig. 5.

With reference to accompanying drawing, we can see that charged particle sensor 1 is the sensitive element of detector, and the shell of this sensor does not show.This shell should be to allow open type that gas passes through and be preferably with the grid that the charged particle that can allow gas and fire starting stage emit passes through.The electrode 2 of sensor 1 and 3 will be illustrated in the back.

Sensor 1 is by resistance 4 ground connection, and the resistance of resistance 4 is 10 megohms (mego-hms).

Between sensor 1 and resistance 4, arrange first measurement point 5.Sensor 1 is very big by a resistance, and the resistance in series 6 that is approximately 1 begohm (gigohm) is connected with power supply.There is node 7 to make the power supply mark.With electric capacity 3 power supply and ground are disconnected.Line powering represents that with a step-up transformer such as figure this transformer 12 is powered between end points 13 and 14, and its secondary coil 15 is by diode 16 ground connection and connect node 7 on the other hand on the one hand.

Must spell out, line power can be a direct current at node 7, and pressing such as power taking is about 1000 volts; Can carry out rectification to power supply according to the conspectus on Fig. 1, primary coil is for alternating current; At last, must point out that also power supply also can be a pulsed, often be like this under the situation of Fig. 1, so primary coil adopts pulse power supply, these pulses can be by the capacitor discharge generation.

Resistance and the supply voltage value of considering resistance 6 can be approximately 10 by the power supply of sensor 1 ^-9To 10 ^-12The amperometric sensor working point should be in below the not continuous discharge district, that is to say, is being in keeping below the avalanche region automatically of corresponding corona discharge effect aspect the intensity.

On Figure 12, people can see that the resistance 6 on Fig. 1 has replaced with several diodes 17, and these diodes all are operated in characteristic The initial segment, and play a high resistance measurement.This configuration is to talking about the adjusting function of current because of the aging voltage that increases sensor.Electric capacity 8 on Fig. 1 also is cancelled.On the contrary, measurement point 5 but has been placed to the back of high value resistor 4, and the two ends of this resistance are then respectively by two very little electric capacity 18 and 19 ground connection.So just can export and be approximately 10 ^-11The integration current of ampere.

The shape of electrode 2,3 is pre-designed, in order that limit interelectrode electric field, avoids discharge.Therefore those electrodes are not made up of some tips respect to one another, and some finger pieces (Fig. 2), ring (Fig. 3), are converted into semicircular lead (Fig. 4) or α shape lead (Fig. 5) or some and are placed on the interior straight lead (Fig. 6) of parallel plane; Article one, lead projects on the plane of another lead and intersect, also have some parallel wires (Fig. 7), the helix (Fig. 8) of parallel placement or the helix of placing (Fig. 9) with another lead in two parallel surface.Also have a kind of columnar coil electrode that is wound in, another electrode is placed on the axle center of cylinder, available straight line (Figure 10), or with helix (Figure 11).The embodiment of these electrodes all is to describe as graphic extension in addition.

Most popular electrode still becomes α shape to wire fold according to synoptic diagram 5.

On Figure 13, α shape electrode is to represent with the shape of folding lead 30.This lead is not perfect, and it has some prickles, and label is 21, because the fine geometric configuration of lead is still effective concerning electric field.For example, the diameter of lead is 100 microns, the lead folding, and its radius-of-curvature is less than or equal to 1 millimeter.

The electrode of this shape especially seems effective for capturing by imperfect combustion charged particle fiery, that particularly emitted by sleeper fire.When these particles were captured by electrode, they are self-discharge just over there, therefore just produce electric current, but they is in that spontaneous combustion again, and this just produces secondary ion.Secondary ion also is captured, thereby causes the obvious increase of electric current.Adopt special alloy or metal formation electrode or cover special alloy and metal on electrode, secondary combustion just can improve.

In some cases, uncharged particle drops on the electrode as sharp dust.Will discharge between this ion and electrode if ion has also arrived on the dust, this is equivalent to the snowslide charge multiplication, and can see the electric current that appearance is bigger this moment.In addition, also produce a kind of chemical reaction in the time of discharge, be equivalent to the reaction of dust oxidation, consequently dust burning that is to say that electrode has purified.

The result who draws thus: the sensitivity that has improved sensor is opened and the self-purging electrode, so sensor just can be worked under lower current/voltage.

With comparing of common ion transducer, its main difference is: by the sensor that the present invention makes, ion of capturing and the secondary ion of capturing increase the electric current in the sensor.On the contrary, the variation of environment temperature, airflow and uncharged particle occurs the electric current in the sensor is not all had tangible influence, this has just been avoided mistake to get angry alert alarm.

When we see Fig. 1 again, just can analyze the detector operation situation with following simplified way: when not having ion, measurement point 5 is in stable potential; When trapping ion was arranged, the electric current in the sensor increased, and the current potential of point 5 changes.

The power supply of sensor can be direct current, interchange or pulse, for example adopts the sampling pulse of 10 to 20 milliseconds of about per seconds.

The present invention especially is fit to the initial situation of detection of fires.Be particularly suitable for surveying sleeper fire and suffer from, method is exactly to capture the small charged particle of being emitted when fire begins by its acquisition sensor.This invention is suitable for surveying cigarette, gas, steam (for example sodium steam), dust, gaseous solvents or ion too.

Claims

1, a kind of particle electric detector, comprise: be used for detecting the sensor (1) that near the charged particle of detector exists, first and second electrodes (2 that this sensor has a pair of space to separate, 3), it is characterized in that: each of said first and second electrodes all and have the shape of alpha to limit electric field between first and second electrodes and reduces the discharge between the two poles of the earth; And

For the sensor provides greatly about 10 ^-9With 10 ^-13The device of the working current between the ampere, said electric current is lower than the required electric current of self-excitation snowslide, and wherein the existence of charged particle causes the increase through sensor current.

2, particle electric detector as claimed in claim 1 is characterized in that: first of first and second electrodes of Alpha (α) type all made by the lead of bending, and has some boundless and indistinct thorns (21) to stretch from the periphery of above-mentioned conduction to collect charged particle.

3, particle electric detector as claimed in claim 1, it is characterized in that: said current supply arrangement comprises that first resistive element (6) and first electrode (2) electrically connect, and said detector comprises that further second resistive element (4) is electrically connected with second electrode (3).

4, particle electric detector as claimed in claim 3 is characterized in that: above-mentioned first resistive element is the resistance with about 10 begohm resistances, and second resistive element is the resistance with about 10 megaohm resistances.

5, particle electric detector as claimed in claim 1 is characterized in that: above-mentioned current supply arrangement comprises that at least one diode (17) and first electrode (2) are coupled electrically.

6, particle electric detector as claimed in claim 1, it is characterized in that: said detector further comprises the resistance (4) that electrically connects with second electrode (3), this resistance has first and second ends, and first and second ground capacitors (18,19) electrically connect with first and second ends of above-mentioned resistance respectively.