Abstract: A spray gun including a turbine mechanism for reducing the turbulence of fanning air to more effectively control the shaping of a conical spray pattern. A spiral flow of fanning air is created by the turbine mechanism. The amount of pressurized air flowing through the turbine mechanism is controlled by a valve mechanism to provide a greater or lesser amount of fanning air. The improved spray gun is particularly useful in paint spray systems wherein air having a flow rate in excess of 5 CFM and a delivery pressure of less than 15 psi over atmospheric is communicated to the spray head of the spray gun. In one embodiment, the turbine and valve mechanisms include first and second sets of circumferentially-spaced inclined vanes, respectively, which cooperate to create the spiral flow of air. The valve mechanism includes an annular valve member which supports the second set of vanes. The turbine mechanism includes a turbine member which supports the first set of vanes.

Abstract: Method and apparatus are provided for electrostatically spray coating an article in a coating zone with a liquid coating material, such as paint, wherein air is supplied to the spray head of an air spray gun at an atomizing air flow rate in excess of 5 CFM and at a delivery pressure of less than 15 psi to atomize the liquid coating material. At this combination of relatively low pressure and relatively high volume of air the transfer efficiency is substantially higher than for conventional air spray guns. A turbine unit filters and heats the air so that the air has a temperature in excess of 70.degree. F. at the spray head. An elongated conductive rod is reciprocably supported within a nozzle of the spray head to create an electrical charge differential between the atomized liquid coating material and the article in the coating zone when charged by a high voltage source. Preferably, the rod is positioned within a liquid discharge orifice of the nozzle to alternatively open and close the nozzle.