GB363628A - A device for the prevention of back fires in gas apparatus - Google Patents

Abstract

363,628. Gas mains &c. ; fluid regulating devices. STEPHENSON, A. and ALLEN-LIVERSIDGE, Ltd., Victoria a Station House, London: Sept. 12, 1930, No. 27346. [Classes 54 and 135.] Means for retarding or arresting the propagation of flame in gas apparatus, particularly suitable in the production and use of acetylene, comprises one or more gas passages formed by closely fitting surfaces in substantially uniform contact, so that they are permeable to gas but impenetrable to flame. In its simplest form, the flame arrester comprises flat rectangular plates 1, 2, Fig. 2, held in uniform surface contact with their edges united in a gastight manner. At their ends, the plates are tapered and slightly flared for connection to supply and delivery conduits 3, 4. In modifications, the plates are corrugated. The plates may be arranged in a closed chamber into which the gas passes from the delivery end of the plates. The pressure set up in'the gas by a back-fire then increases the contact pressure of the plates and, consequently, the resistance to the passage of flame between the surfaces. Several deliveries may be taken from a pair of plates, or passages formed by pairs of contacting plates may be arranged in parallel. The heat absorption capacity of the plates may be augmented by the provision of radiation fins 6, Fig. 7, or by immersion of the device in a cooling medium such as water, in which a chemical such as sodium acetate may be dissolved. In Fig. 11, contacting plates 8, 9, 10 are arranged in a jacket 11 in which cooling medium is circulated by a pump 16. The contact pressure of the plates can be varied by varying the pressure of the cooling medium, or by means of a screw 20. By increasing the pressure sufficiently, the plates can be caused to act as a cut-off valve for the gas supply. In order to increase the length of the gas passage, the contacting plates may be made in the form of nested cups, bells, &c. and may enclose a space for a cooling medium under pressure. In another modification, Fig. 12, the contacting plates are formed as concentric cylinders, alternate cylinders 23, 24, in this instance, being of metal and asbestos cement. The gas flows in sequence between the cylinder surfaces from the inlet 22 to the outlet 31, the ends of the metal cylinders, which are set in end blocks 29, 32, being serrated. The annular space 30 may serve for the circulation of cooling medium. In other modifications, the contacting surfaces are constituted by the walls of a flattened tube, which is bent to an adjustable curvature to vary the pressure between the surfaces. As applied to the protection of high-pressure storage cylinders, annular discs or laminµ are held in adjustable contact by springs or screws. As shown, Fig. 16, a hollow perforated delivery tube 44 depending from the valve housing 43 of the cylinder 42 is surrounded by a series of helically-wound elements 47, adjustment of a nut 49 varying the pressure between the surfaces of the elements. In any of the examples, the plates may be made of the same or different materials, and may be impregnated or coated with a desiccating, fire-proofing, or gaspurifying agent. The pressure on the surfaces may be obtained or maintained in a variety of ways.