High velocity spray torch for spraying internal surfaces

A high velocity oxygen fuel (HVOF) or high velocity air fuel (HVAF) thermal spray apparatus to apply coatings to external and internal surfaces of a target, said HVOF or HVAF thermal spray apparatus comprising:

• a combustion chamber having a primary passage for combustion of fuel received through a fuel input line with oxygen or air received through an oxidizing gas input line;
• a divergence section downstream of said combustion chamber, the divergence section having two or more channels diverging relative a longitudinal axis of the primary passage of the combustion chamber;
• an elbow housing downstream of said divergence section;
• a nozzle housing downstream of said elbow housing, the nozzle housing retaining a nozzle having an injection zone and a nozzle throat;
• a convergence section retained between said elbow housing and said nozzle housing, the convergence section having two or more channels converging toward the injection zone of said nozzle;
• a feedstock injector for the injection of feedstock material for forming said coatings into the injection zone of said nozzle;
• and
• a plurality of passageways extending through said combustion chamber, said divergence section, said elbow housing, and said convergence section for passing a coolant therethrough.