GB664930A - - Google Patents

Abstract

664,930. Spray-producers. SCHORT METALLISING PROCESS, Ltd. March 10, 1950 [March 21, 1949], No. 7668/49. Class 69 (iii). A pistol for coating surfaces by spraying a powder which is melted or sintered by a flame produced by burning a combustible gas, has the powderconveying nozzle 15 tapered towards the throat and an annular chamber 16 is interposed between the nozzle 15 and the outlet or outlets 7 of the passages at which the gas is burnt. The gas mixture is delivered from an inlet 2 via channels 5 and 6 to the fluted outlet 7, and powder, drawn in at 19 by an injector 11, is passed to the outlet 15. Between the outlets 7 and 15 is the fluted outlet 16 to which is passed cooling air from an inlet 8, radial passage 12, and annulus 14. This air forms a cold sheath protecting the air-powder mixture, emerging at 15, from the flame emerging at 7, and ensures its melting after leaving the outlet 15. The injector 11 is retained by a spring 22 fitted in a detachable cap 23, the air to the injector also being supplied from.the inlet 8. If desired, the combustible gas mixture may be conveyed by holes 24, Fig. 2, to an annulus 25 having peripherably dispersed apertures 26, the powder emerging from 27 being then heated by radiation only. The cool air. sheath is retained however. Another embodiment, Fig. 4 (not shown), differs in that the powder is fed by pressure, and not by means of an injector, the apparatus otherwise being similar to the first described embodiments. Specifications 432,831, 624,066 and 644,280 are referred to.