Combustion wire spray process

The combustion wire process uses a combustion flame approximately 2700 °C with compressed air to accelerate molten particles shedding from a centrally fed wire. The velocities are less than the HVOF systems and there is considerably less thermal energy from the system. The molten particles form from the melting wire and are therefore molten when leaving the wire and the acceleration and effective flame temperature can be adjusted. The feedstock material must be in wire or rod form. Composites, metals and ceramics can be sprayed with this system. The operator protection required is minimal. 

For gas combustion processes, the lower-energy flame spray process uses oxyfuel combustible gas as a heat source to melt the coating material, which may be in the form of rod, wire, or powder. In the higher-energy, high-velocity oxyfuel combustion spray (HVOF) technique, internal combustion of oxygen and fuel gas occurs to produce a high-velocity plume... 

There are three basic categories of thermal spray technologies combustion torch (flame spray, high velocity oxy-fuel, and detonation gun), electric (wire) arc, and plasma arc. Thermal spray processes are maturing, and the technology is readily available. 

Cable tray fires have resulted from the accumulation of process leakage, residues or combustible dusts or debris on top of cable trays with densely packed wires and cables. Covering shields above cable trays have been used to minimize such accumulations however, such shields should be used with caution as they can limit air circulation and increase cable and wire temperatures in densely loaded trays particularly those carrying power cables. Covering shields may also block fixed fire protection water spray or manually applied firefighting water spray from reaching the cables. 

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