GB829370A - Improvements in or relating to heat-fusible material spray guns - Google Patents

Abstract

829,370. Spraying fusible materials. METALLIZING ENGINEERING CO. Inc. March 13, 1957 [April 13, 1956], No. 8266/57. Class 69 (3). A flame spray gun for fusible powders supports a tubular hopper 2 containing the powder which, in operation, falls by gravity through a hole 5 and from the outlet of a flexible rubber tube 13 to a chamber 19 and to a slot 29 in a plug 23. Fuel gas flowing along a passage 21 passes through a jet screw 30 and carries the powder centrally through the plug and nozzle 26 to the combustion zone. Powder flow is controlled by a trigger-operated valve piston 16, which, in the non-spraying position, is urged rearwardly by a spring 83 to squeeze closed the outlet end of the rubber tube 13. A trigger 70, pivoted at 71, has a cross-pin 73 which engages a slot in a hollow square piston 74. A piston 79 slides within piston 74 and is urged forwardly by a spring 80, and a stop 82 limits movement of the inner piston. Cut-outs 85, 86 in the piston 74, and a groove 85a in the partition between the cut-outs, engage with projections on a cam 92, pivoted at 77, and acted upon by a spring 78, so that when the trigger is urged rearwardly against a spring 71 the pistons 74, 79 are urged forwardly and piston 16 is moved forwardly to open the tube 13. The cam locks the piston 74 in the forward position and the powder valve remains open. To release the valve, the trigger is again squeezed to disconnect the cam and the piston 74, and is then released, whereby the piston will return to its original position shown in Fig. 2. Fuel gas is fed through the gun rear through a valve-controlled inlet F, and flows along passages 42 and 44 to a bore 40, and com-. bustion supporting gas is similarly fed through a valve-controlled inlet O to passages 41, 43 to bore 40. The gas mixture passes to circumferentially-spaced passages 37 in the nozzle 26, and converging passages 38 for induced air are circumferentially spaced around the nozzle to prevent the tendency of material to collect on the nozzle face. A proportion of fuel gas is led from passage 42, Fig. 3, through a passage 64 to a bore 55 in which a needle valve body 56 fits, and a threaded needle 57 operated by a handle 58 controls the flow of fuel gas through the valve body and passages 90, 63, Fig. 2, to a bore 65 leading to the passage 21. A detent piston 88 engages grooves 87 in the valve handle 58 and provides means for determining the valve setting. Atmospheric pressure in chamber 19 is provided by a hole 35. An electric vibrator may be attached to the gun body. A larger hopper may be supported above the gun and connected to it by flexible hose.