Thermal spray method and apparatus for optimizing flame jet temperature
First Claim
1. In a method of thermal spraying of a powdered material by entrainment of particles of said powdered material in a supersonic flame jet from one of an oxy-fuel, air-fuel, or plasma heat source and expanding the flame jet to atmospheric or lower pressure characterized by a temperature above the melting point of the material being sprayed, the improvement comprising reducing the jet temperature after such expansion to below the melting point of the material prior to introduction of the material particles into said flame jet.
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Accused Products
Abstract
An internal burner combusting an oxy-fuel or air-fuel mixture, or a plasma heat source providing a supersonic flame jet which when expanded to atmospheric or lower pressure is characterized by a static temperature well above the melting point of a material in particle form being sprayed by the flame jet and the step of reducing the flame jet temperature after reaching supersonic velocity to a temperature below the melting point of the material prior to feeding of the material particles into the flame jet. The jet temperature reduction may be effected by injecting directly into the flame jet stream an amount of liquid or gas fluid which will reduce the flame jet temperature by the required amount. Alternatively, the supersonic flame jet may be passed through a concentric heat exchanger bearing a coolant medium such as water to absorb the necessary amount of heat from the flame jet to reduce the flame jet temperature to below the melting point of the material.
55 Citations
8 Claims
- 1. In a method of thermal spraying of a powdered material by entrainment of particles of said powdered material in a supersonic flame jet from one of an oxy-fuel, air-fuel, or plasma heat source and expanding the flame jet to atmospheric or lower pressure characterized by a temperature above the melting point of the material being sprayed, the improvement comprising reducing the jet temperature after such expansion to below the melting point of the material prior to introduction of the material particles into said flame jet.
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6. In a flame spray method using an internal burner having a body including a combustion chamber, said method comprises the steps of:
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feeding a fuel and oxidizer mixture into said combustion chamber and igniting said fuel and oxidizer mixture to effect a combustion within said combustion chamber, expanding gaseous products of the combustion from a terminal face of the burner body through a restricting nozzle to form a flame jet which when expanded to atmospheric or lower pressure is characterized by a temperature above the melting point of a powder material to be sprayed into the flame jet to accelerate particles of said powder material to supersonic velocity, the improvement comprising; reducing the jet temperature to below the melting point of the powder material prior to a point where a powder flow of material phase into the flame jet. - View Dependent Claims (7, 8)
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Specification