초록

Disclosed is a method of, and apparatus for, flame spraying particulate material utilizing the thermal energy of a very hot gaseous primary stream produced in an oxy-fuel combustion chamber combined with kinetic energy from a surrounding annular sheath of warm high velocity secondary air.

대표청구항 ▼

In a method for flame spraying a coating of the type in which an oxy-fuel mixture is combusted in a duct to produce a high temperature and high velocity columnar flame jet which is used to heat and propel a solid material from the duct toward a substrate, the improvement comprising the steps of: pro

In a method for flame spraying a coating of the type in which an oxy-fuel mixture is combusted in a duct to produce a high temperature and high velocity columnar flame jet which is used to heat and propel a solid material from the duct toward a substrate, the improvement comprising the steps of: providing a stream of uncombusted compressed air separate from the oxy-fuel mixture, heating said stream of air above ambient temperature by flowing said stream along the exterior of said duct while absorbing heat therefrom, and maintaining the exit velocity of said flame jet subsonic while surrounding said columnar flame jet with a co-axial sheath of expanded compressed air having a velocity which is sufficiently close to the velocity of said flame jet so that there is little initial mixing of said sheath and said jet.