Highly concentrated supersonic material flame spray method and apparatus

A highly concentrated heat softened or liquified material flame spray apparatus comprising:

• a spray gun body,
• passage means defining an essentially closed electric arc heating zone within said body,
• means for continuously flowing a gas under pressure through said heating zone passage,
• said body including electrical heating zone discharge passage means at one end thereof,
• said body further comprising an elongated nozzle downstream of said electrical heating zone discharge passage means,
• said nozzle including a converging inlet bore portion leading to a throat and having an extended length outlet bore portion, and wherein said bore has a length that is at least five times the diameter of said nozzle bore throat,
• said electrical heating zone discharge passage means comprising means for conveying a converging flow of the discharging electrically heated gas after exit from the electrical heating zone into the entrance of said nozzle inlet bore portion, and
• means for introducing material in solid form outside of the electrical heating zone axially into the hot gas for subsequent heat softening or melting and acceleration, with the point of introduction of the solid material being at the entrance to or within the converging inlet portion of the nozzle bore, to prevent build-up of particle material on the nozzle bore wall while insuring sufficient particle dwell time within the gas stream to effect particle heat softening or melting prior to particle impact on a substrate downstream of the discharge end of said nozzle bore.

A highly concentrated, hot gas supersonic abrasive blast apparatus comprising:

• an abrasive blast gun body,
• a high pressure, essentially closed combustion chamber within said body,
• means for continuously flowing an oxy-fuel mixture under high pressure through said combustion chamber for ignition within said chamber,
• said body including combustion chamber products of combustion discharge passage means at one end thereof,
• said body further comprising an elongated nozzle downstream of said combustion chamber discharge passage means,
• said nozzle including a converging inlet bore portion leading to a throat and having an extended length outlet portion leading from said throat,
• and wherein said bore has a length that is at least five times the diameter of said nozzle bore throat,
• said combustion chamber discharge passage means comprising means for conveying a converging flow of the discharged hot products of combustion, after exit from the combustion chamber, into the entrance of the nozzle inlet bore portion, and
• means for introducing solid, particulate, abrasive material outside of said combustion chamber, axially into the hot combustion gases for acceleration thereby with the point of introduction of the particulate abrasive material being at the entrance to or within the converging inlet portion of the bore of said nozzle to restrict the diameter of the column of particles passing through the nozzle bore and prevent contact of the particles with the nozzle bore wall and erosion of the nozzle bore while accelerating the particles to very high velocity prior to particle impact on a workpiece downstream from the discharge end of the nozzle bore.