DE1277711B - Device for detecting smoke particles or combustion products - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4MTGs ^ PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

G08b

German class: 74 a - 33

P 12 77 711.6-35 (Y 1016)

December 23, 1965

September 12, 1968

The invention relates to a device for detecting smoke particles or combustion products, in which the voltage occurring at an electrode is actuated by means of an amplifier Display device or the like. Is determined.

In the previously known devices of this type, the gas to be examined, ζ. B. that of Rauch the other combustion products permeated air, passed through a chamber containing an ionizing, z. B. contains radioactive preparation and two electrodes, between which a relatively high potential difference is maintained. When the gas permeated by smoke passes through, the potential difference changes between the electrodes, and this potential difference becomes an indication after amplification brought. A combination of two such chambers is also used to increase the measurement accuracy used, one of which flows through the gas to be examined and the other against the Outside air is closed. The difference is then used to display smoke ÜJ for the gas to be tested the ionization currents that occur in the presence of smoke or the like in the two chambers.

It is also already known to measure the electrical charge in the atmospheric air Device to use in the case of air with a fan through an electric condenser forming probe device is sucked and in which the change in charge of the probe device, which is caused by the electrical charge of the air, in a certain order automatically to amplifier, Storage and other auxiliary devices and via these is placed on a measuring instrument. In order to measure the very small electrical conductivities of the air, the electrodes of the probe device are used A suction voltage is applied by means of an induction capacitor. However, such a device is as a display device for smoke particles and combustion products, i.e. for constant monitoring of a room, not suitable, as the periodic switching processes provided for it are a lot would require too much effort.

The known devices used to detect smoke or the like have the disadvantage that they use radioactive radiation sources for ionization and that they apply high voltages to the measuring electrodes to generate the ionization currents require. The use of radioactive sources of radiation in inhabited areas is endangered but as is well known, the people staying in these rooms. It also requires the use a high suction tension not only a constant

Device for detecting smoke particles or combustion products

Applicant:

Yissum Research Development Company,

Jerusalem (Israel)

Representative:

Dr. G. W. Lotterhos

and Dr.-Ing. W. H. Lotterhos, patent attorneys,

6000 Frankfurt, Annastr. 19th

Named as inventor:

Abram Aubrey Jaf f e,

Eliahu Nadav, Jerusalem (Israel)

Claimed priority:

Israel of December 27, 1964 (22 673)

as dig working voltage source, but also a Appropriate isolation of the device from its surroundings, which leads to the formation of smoke indicating electrode sets narrow limits.

The present invention is based on the experimental finding that the smoke all substances that are unambiguous for a possible fire or the like having. These charges can have a positive or negative sign depending on the type of substance burned have, however, the smoke always contains predominantly charges of a single sign. These Charges can now influence voltages on an insulated electrode.

The invention makes use of this fact. In the present device for detection of smoke particles or combustion products, in which the one that occurs on an electrode Voltage is determined by means of a display device or the like operated via an amplifier According to the invention, the electrostatic charging of the electrode which is not biased by those flowing past it and not influenced by any particular ionization source Smoke particles or combustion products.

In this way, the invention avoids the above-mentioned disadvantages of the known devices

809 600/182

Claims (2)

3 4 and is accordingly far simpler than this. Can also be designed. The amplifier 15 can offer They have the great advantage that they cannot be of a type that depends on voltage at the electrode can be given any shape to speak of or of any type that attaches to charge Protection for large and / or irregularly shaped speaks. The output of amplifier 15 is on and / or to obtain limited areas. The well-known 5 relays 16 connected, which is a pair or th devices, especially those with two ionic contains several pairs of electrical contacts 17, the Sation chambers, on the other hand, are relatively corn- are switched by the relay 16 in such a way that plicated and therefore their size and shape can trigger an alarm device 18 and / or an automatic one badly adapted. Fire fighting device 19 are operated. Advantageously, the electrode is from a grounded, io The device according to the invention works the smoke particles or the like permeable shielding as follows (see. Fig. 1): The smoke particles or surrounded by one or more layers of combustion products that carry an electrical charge an electrically conductive one provided with holes pass through the holes in the shield Material. 11 a, and the approximation of said particles From the following description of the drawing 15 to the element 12 induced on its surface Further features of the invention emerge. a load. As already noted, the production It shows the generation of a charge on the surface of the element F i g. 1 schematically shows a device for fixed 12 by the changes in the electrical potential position of smoke particles or combustion pro- products according to the invention, 20 more likely to flow towards the conductor or flow away from it, F i g. 2 a circuit diagram of an amplifier which is monitored or measured when the conductor is connected to rather in connection with a device according to a fixed potential, e.g. B. is connected to earth. Invention can be used and If the amplifier 15 is of the type that on Fig. 3 responds to an electrical circuit of an alarm precharge changes, the current that direction flowing between element 12 and earth in connection with the amplifier according to FIG. 25, through the F i g. 2 can be used. Amplifier 15 amplified, and the coil of relay 16 The device (see. Fig. 1) has a sensing element is energized so that a pair or more pairs of 12, as which z. B. a metal electrode (i.e. elek contacts 17 closed and the alarm or fire table conductive material) can serve, the preferential combat device 18 or 19 in action Is designed like a grid or perforations 30 is set. and is hollow inside. This sensing element 12 can In Figs. 2 and 3 is a circuit diagram of a have any shape; it can e.g. B. shown as a long amplifier and an alarm device, the Cylinder be designed, which is several meters in length in connection with the device for measuring the has, or it can be used as a flat box or as a sheet load (see. Fig. 1). It is trained to emphasize protection over a large area 35 that the amplifier shown here to obtain, e.g. B. over the ceiling of a room or and the alarm device only exemplary embodiments the area of a roof. Representing the adaptability of the invention and that thereby the inventors The shape of the electrode and the simplicity of the procedure are not limited. direction according to the invention are essential Without going into the details of the in F i g. 2 representation meaning, and it is to go on the basis of these properties of the circuit diagram (since all elements practiced in possible, an appropriate fire protection for licher way are designated), can determine who-rooms or surfaces of the most varied shapes to earth that the element 12, which is earthed by one. . th shield 11 is surrounded, the entrance for The sensing element 12 sits on the insulator piece 13, wel- the field effect transistor Q 1 of the first stage of the Ches made of a material with high insulating properties 45 represents charge amplifier 15. The outcome of the stands, e.g. B. Polytetrafluoräthylän; it is from an amplifier 15 provides the input of the alarm device Surrounded earthed shield 11, the purpose of which represents, the output coil RL 1 is excited to consists in the element 12 to close the multiple contacts 17 against any external charge and the or shield fields, while on the other hand smoke alarm and / or fire-fighting equipment particles and combustion products flow through 50 actuate. men can. The shield 11 consists of elec- electrically conductive material, preferably described in the form of smoke gas identification, the actuation of which a wire mesh or a perforated sheet. The movement depends on the induced charge of a Shield 11 is shown in FIG. 1 as a single metal-single electrode, and that charge becomes layer shown; however, it can become effective due to the presence of the electrical charge. electrical shielding made up of several layers, which protect the smoke particles or the th consist of electrically conductive material. have combustion products. The device according to The shape or the outline limitation of the shielding of the invention has a significant advantage Mungll should be compared with the shape and the outline of its simple design and function tion of the element 12 essentially corresponds to 60 with known devices, while also correct, but be a bit bigger. If z. B. the excellent adaptability of the element Element 12 is designed as a long cylinder, 12 should be present so that the best possible resp. the earthed shield 11 consists of a coaxial greatest protection over large and irregular or gen cylinder or is obtained from a number of difficultly delimited surfaces. Cylinders surrounding the element 12. 65. The electrical connection to the electronic claims:
Amplifier 15 is produced by the insulated line 14 1st device for detecting smoke, the particles or combustion products as a coaxial conductor of conventional design, in the the voltage occurring at an electrode by means of a display device operated via an amplifier or the like. is established, characterized in that the electrostatic Charging of the electrode (12) which is not biased by the one flowing past it and smoke particles or combustion products are not influenced by any particular ionization source. 2. Apparatus according to claim 1, characterized ge ίο indicates that the electrode (12) from a grounded, the smoke particles pass through Shield (11) is surrounded, which consists of one or more layers of a perforated electrically conductive material. Considered publications:
German patents nos. 901 319, 718 327, 073;
German exploratory documents No. 1114 413, 089 193.1 056 008. 1 sheet of drawings 809 600/182 9.68 © Bundesdruckerei Berlin