RU1803925C - Spark-type explosion hazard alarm - Google Patents

Abstract

The invention relates to pneumatic automation, in particular to pneumatic spark detectors, of explosive ™ combustible gases and vapors in the air of industrial premises, and can be used to detect emergency situations in potentially hazardous industries. The purpose of the invention is to increase the sensitivity and simplify the design. The detector contains an explosion chamber with integrated spark generator electrodes based on piezoelectric elements (4) located in a rigid housing (f4) with

Description

the possibility of axial deformation mx using a membrane adder (5) with a rod (15) mechanically connected to piezoelectric elements (4), as well as a test and combustible gas mixer connected to the explosion chamber, an explosion detector and input and output flame arresters. To achieve the goal, the explosion chamber is made in the form of a truncated cone, to the larger C101 and small (11) bases of which, at their intersections with the generatrices (12) of the cone, input and output fire arresters are connected from its opposite sides, respectively, and to a small base ( 11) explosion chamber, vertically located in space, is also attached to the body (14) of the spark generator, a piezo

elements (4) of which are electrically connected to each other, and their minus and plus electrodes are connected to the minus and plus electrodes of the spark generator directly and by means of a spring tab (20), respectively. The explosion chamber and the body (14) of the spark generator are interconnected with the formation of a cylindrical explosion-proof. of the gap, between the extreme piezoelectric elements (4) and the spark generator housing (14), movable and fixed stops (16) are installed, which also form cylindrical explosion-proof slots, and the movable stop (16) is mechanically connected to the rod (15) of the membrane adder ( 5). 1 C.p. f-ls, 2 ill.

The invention relates to pneumatic automation, in particular to pneumatic spark detectors for combustible gases and vapors in the air of industrial premises, and can be used to detect emergencies in potentially hazardous industries ..-: The purpose of the invention is to increase sensitivity and simplify the design.

Figure 1 presents a schematic diagram of a signaling device; FIG. 2 is a structural diagram of an explosion chamber and a spark generator,

The detector consists of an explosion chamber 1 with fire suppressors 2, and a spark generator 3 s. a voltage source made in the form of piezoelectric elements 4, a membrane adder 5, an explosion detector 6, a test and combustible gas mixer based on an ejector 7 and constant chokes 8, 9, as well as a control unit for the forming pulse P (not shown in Fig. 1) . The chamber 1 (Fig. 2) is made in the form of a truncated cone with a large 10 and a small 11 base and generatrices 12. At the base 11, the electrodes of the generator 3 are installed (negative welded to the base, and positive mounted to the base using PTFE seal 13, Piezoelectric elements 4 are located in the housing 14 of the generator 3 and are mechanically connected with the rod 15 of the adder 5, located on the same axis with the piezoelectric elements. Between the extreme piezoelectric elements 4 and the housing 14 are fixed and movable stops 16, forming with the housing 14

Drica flameproof gap. The fixed stop 16 is fixed in the housing by a nut 17 with a lock nut 18, and the movable stop 16 directly abuts against

rod 15. Piezoelectric elements 4 are isolated from the housing 14 by a fluoroplastic sleeve 19. The negative electrodes of the piezoelectric elements are connected to the negative electrode of the generator 3 directly due to the mechanical

contact them with the stops 16 and the housing 14, and the positive connected to the positive electrode using a spring tab 20. The base 11 and the housing 14 are interconnected by screws (not shown in figure 2), so

that a plane-cylindrical explosion-proof gap is formed between them (explosion-proof connections are shown in Fig. 2 by double lines), To the chamber 1 at the intersections of the generators 12 s

the bases 10, 11 on opposite sides of the cone are connected to the input and output flame arresters 2, made, for example, in the form of cylindrical cups 21 of cermet based on sintered titanium powder. A cup 21 is located in the housing 22, closed by a lid 23, In the housing 22 a hole is made for supplying: gas, and the housing itself is welded to the base.

The signaling device works as follows. Using an ejector, the test and combustible gases are continuously sucked through the chokes 8, 9, the inlet flame arrester 2, the chamber 1, and the output flame arrester 2 into the gas discharge line. Due to the porous structure of the inlet flame arrester 2, the studied and combustible gases are almost completely mixed at the entrance to the chamber 1.

Since the pressure of the studied and combustible gases before the throttles is equal to atmospheric pressure, with a certain change in the vacuum in the chamber caused, for example, by a change in the resistance of the flame arresters 2 or the power of the ejector 7, the ratio of the flow of these gases will be unchanged.

At certain points in time, control pulses are supplied to the input of adder 5, under the action of which 15 impulses of force compressing the piezoelectric elements 4 appear. Thanks to the direct piezoelectric effect, an electric charge arises on the electrodes of the piezoelectric elements 4, which causes a distortion upon reaching a certain voltage the discharge between the electrodes of the generator PCJ 3. If the total concentration of combustible components in chamber 1 introduced by the combustible gas and located in the test gas reaches a level. explosive ™, then at the moment of ISKRA formation in the chamber 1, an explosion will occur, which will be detected by the detector 4 by the pressure pulse in the chamber. Then, at P .0, the explosion products will be removed from the chamber and for some time the chamber will be filled with a fresh mixture of the analyzed and combustible hafs.

The execution of the chamber 1 in the form of a truncated cone increases the sensitivity of the signalizer by increasing the blasting power and, consequently, the pressure pulse in the chamber at the time of the explosion. Formula Mule Found

1, A spark hazard detector containing an explosion chamber;

a test and combustible gas coupler connected through an inlet and outlet flame arrester to an explosion chamber, an explosion detector connected through an outlet flame arrester to an explosion chamber, and a spark generator whose electrodes installed in the explosion chamber are connected to a voltage source, made in the form of piezoelectric elements, sequentially installed in the spark generator housing with the possibility of their axial deformation and connected with the rod of the membrane adder, the input of which is connected to the control unit, and therefore, in order to increase the sensitivity and simplify the design, the explosion chamber is made in the form of a truncated cone, at the large and small bases of which there are respectively input and output fire arresters, and the spark generator body is attached to the small base of the vertically located explosion chamber, while the explosion chamber and the body spark generators are interconnected with the formation of a plane-cylindrical explosion-proof gap, movable between the extreme piezoelectric elements and the spark generator housing and fixed stops, which form cylindrical explosion-proof slots with the body, and the movable stop is mechanically connected with the rod of the membrane adder. 2, The signaling device according to claim 1, wherein the mixer of the test and combustible gases is made in the form of two constant chokes installed in the lines of the test and combustible gases connected to the input flame arrester, and an ejector with power channels, reset and the input communicated with the output flame arrester.

Test gas

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Flammable gas

in 2

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