Method and apparatus for high velocity flame spraying of asymmetrically fed wire rods

In a flame spray method comprising the steps of:

• continuously combusting, under pressure, a continuous flow of an oxy-fuel mixture confined within an essentially closed internal burner combustion chamber,
• discharging the hot combustion product gases from the combustion chamber through a flow expansion nozzle as a high velocity hot gas stream flame jet, and
• feeding material to the stream for high temperature heat softening or liquefaction,
• spraying at high velocity onto a surface positioned in the path of the stream at the discharge end of the nozzle and spaced downstream therefrom,
• the improvement wherein the step of feeding said material comprises feeding said material in solid rod form, outside of said combustion chamber asymmetrically and continuously into said flame jet at an angle to said flame jet and at a point downstream of the exit from the flow expansion nozzle with said introduction angle of the rod relative to the flame jet axis and the rod diameter being such that the rod bends within the flame jet to line up the rod tip with the flame jet axis;
• whereby, a liquid film develops about the periphery of the rod within the flame jet as a full symmetric circumferential coating about the unmelted portion of the rod within the flame jet, and the flame jet produces a very fine suspension of particles of the material forming the rod within the flame jet stream.