GB1016808A - Improvements in or relating to powder-fed flame-spraying torches - Google Patents

Abstract

1,016,808. Spray-producers; flame torches. EUTECTIC WELDING ALLOYS CORPORATION. Dec. 20, 1963 [July 26, 1963], No. 50433/63. Heading B2F. In a powder-fed flame spraying torch 10 in which powder is fed from a resilient container 26 through a valve orifice 46 and a passageway 22 to a space 34 the powder is entrained by the combustion supporting gas before it is introduced to the combustion gas in a mixing chamber 28. The torch comprises interconnected parts 20, 14 and 12, the latter incorporating the nozzle tip. The part 20 includes acetylene and oxygen conducting passages 16 and 18 whilst the central part 14 incorporates the passages whereby the gases and powder are conducted to the mixing chamber 28 as well as the coupling means by which the powder container 26 and a suitable torch handle are connected thereto. The powder feed control valve comprises a rubber member 44 having the orifice 46 which is normally closed under "squeezing" pressure arising from a spring-loaded plunger 48. Such pressure is released on actuation of a pivotally mounted handle 50. The mixing chamber 28 and feed passages 49, 38, 30, 63, 59 are formed in an assembly comprising a flanged member 43, a member 45 having an intermediate flange 55 and a sleeve 47 having powder feed passageways 63 which surrounds parts of both members such as to allow the formation of the powder reception space 34 between them. In operation, acetylene from the passageway 16 passes around a circular duct 51 and through three equi-angularly spaced ducts 49 in the flange of the member 43. The gas then passes. along two longitudinal ducts 53, Fig. 6, into an annular duct 57 from which it passes to the mixing chamber 28 through three equiangularly spaced ducts 59. The oxygen, on the other hand, passes from the passageway 18 through the centre of the members 43 and 45 entraining the powder as it emerges from a restricted section 30 of its passage through the member 43. Flash back is prevented in the present torch by mixing the powder with the oxygen prior to the mixing chamber and also by maintaining the oxygen pressure at between 16 and 25 pounds per square inch whilst keeping the pressure of the acetylene between 3 and 4 pounds per square inch. The sleeve 47 has two powder feed passageways 63 such that it may be correctly inserted into the torch part either way round.