Abstract: A flame spray coating system includes a thermoplastic resin powder supply hopper, an eductor adapted to entrain powder in a stream of conveying air, a valve disposed between the powder hopper and eductor for controlling the flow of powder from the hopper into the eductor, a flame spray gun and conduits interconnected between the flame spray gun and pressurized air and combustion gas sources for delivering flows of propelling air, conveying air, powder entrained in conveying air, and a combustible gas to the flame spray gun, and an eductor control disposed on the flame spray gun for controlling operation of the valve disposed between the powder hopper and eductor. A solid circular coating pattern is created with a nozzle constructed for twirling the entrained powder and conveying air. Interchangeable combustion nozzles of different sizes allow the same spray gun to be used for different substrate conditions.

Abstract: In an open-atmosphere flame spray gun system for spraying molten particulate material and a method of spray application, an improved eductor mechanism and flame spray gun permits a greater quantity of particulate material to be delivered to the article to be coated. The particulate material entrained in a stream of pressurized conveying air, a stream of pressurized burn/propelling air and a stream of fuel gas are delivered through a plurality of passageways extending through the gun body to a combustion chamber for mixing and ignition. The streams are delivered in concentric annular relationship to the combustion chamber, with the stream of particulate material and conveying air and concentric annular stream of burn/propelling air being directed into the combustion chamber in an outwardly expanding conically-shaped axial cross-section for enhancing the diameter and length of the flame produced by the gun and permitting an increased quantity of particulate material to be melted and delivered for coating.