Suction feed nozzle assembly for HVLP spray gun

摘要

For an HVLP paint spray gun, an improved suction feed nozzle assembly including a fluid tip and an air cap. The air cap directs an annular flow of atomization air around a fluid discharge orifice formed by a tubular portion on the fluid tip to aspirate fluid from the orifice and to atomize the fluid. The air cap also directs pattern shaping air at the atomized paint. According to one feature of the invention, the spacing of the pattern shaping air orifices from the fluid discharge orifice is made sufficiently great that undue turbulence is not induced in the atomization air in the aspiration zone to maximize the fluid flow rate. According to a second feature of the invention, the fluid orifice in the fluid tip has a straight cylindrical portion and an expanding conical section connecting the cylindrical section to an annular flat front face of the tubular portion of the fluid tip. The flat portion of the front face on the tubular portion is kept to a minimum to increase the particle distribution uniformity of the atomized paint. Preferably, a sharp comer if formed between the flat face and the sides of the cylindrical section to optimize fluid flow at low air pressures.