Powder Flame Spray Gun
The diagram illustrates a typical powder flame spray gun. Powders are fed either by gravity or from a powder feeder by a carrier gas. Nozzles generate the flame, introduce the spray material, and shape the spray pattern. In conventional flame spray guns, oxygen and fuel mix inside the nozzle, exiting through a set of holes in the face of the nozzle. Combustion occurs at the nozzle exit, and combustion gases are free to expand.
In some powder-fed gun designs, a constricting flow of air is fed through a concentric set of holes near the nozzle exit and is used to pinch the expanding gases, generating a higher-temperature combustion zone, and accelerating the molten powder.
Volume 5A, Thermal Spray Technology -> Thermal Spray Processes and Coatings -> Thermal Spray Processes -> Processing Characteristics
