Abstract: A vent block for use in controlling powder surging in a flame spray coating system having a flame spray gun with an eductor disposed inside the gun, the vent block being disposed between the powder source and the gun, the vent block having intersecting powder and vent air flow paths communicating with an outlet flow path, the cross-sectional areas of the powder and vent air flow paths being substantially equal to each other, and the combined cross-sectional areas of the powder and vent air flow paths being about one half the cross-sectional area of the outlet flow path.

Abstract: A flame spray gun comprising a trigger-operated valve for selectively controlling the flow of conveying air to an eductor disposed in the powder flow nozzle, thereby providing the operator with substantially instantaneous control over the powder feed rate through the gun.

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: A feed system for flame spray guns is provided that comprises a hopper with a powder storage chamber, a pressurized gas source separated from the powder storage chamber by a gas distributor board, at least one flow line providing fluid communication for the pressurized air and entrained powder between the storage chamber and a flame spray gun, a powder outlet valve on each flow line for controlling the flow of pressurized gas and entrained powder from the storage chamber into the flow line, and a purge line delivering pressurized gas to the flow line downstream of the powder outlet valve for clearing powder from the flow line after the valve is closed.

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.

Abstract: In an open-atmosphere powdered flame spray gun and method of spray application, a plurality of passageways extending through the gun body delivers a powderized thermoplastic, combustion air, and a fuel into an open mixing and combustion chamber defined by a hood about the body. The resultant mixture ignites melting the plastic, which is then expelled from the chamber by a source of propelling air so as to provide a plastic coating about a desired object.