Symmetrical multi-port powder injection ring
Powder injection apparatus, plasma gun, and method of use. Powder injection apparatus includes a shroud attachable to an outlet nozzle of a thermal spray apparatus and a substantially smooth and continuous inner wall defining a bowl through which a plume of the thermal spray apparatus travels. At least one port in the inner wall is structured and arranged to receive a powder injection nozzle that injects powder into the plume.
1. A powder injection apparatus, comprising:
a shroud attachable to an outlet nozzle of a thermal spray apparatus, wherein the shroud comprises:
a substantially smooth and continuous inner wall defining a bowl through which a plume of the thermal spray apparatus travels, and
at least one port in the inner wall structured and arranged to receive a powder injection nozzle that injects powder into the plume.
2. The apparatus of claim 1 , wherein the at least one port comprises a plurality of ports.
3. The apparatus of claim 2 , wherein the plurality of ports are arranged radially with respect to at least one of:
a longitudinal axis of the shroud;
a central axis of the outlet nozzle; and
a longitudinal axis of the plume.
4. The apparatus of claim 2 , further comprising a plurality of powder injection nozzles corresponding to the plurality of ports.
5. The apparatus of claim 4 , wherein an outlet end of each respective one of the plurality of powder injection nozzles is substantially flush with the inner wall.
6. The apparatus of claim 4 , wherein an outlet end of each respective one of the plurality of powder injection nozzles extends through the inner wall into a volume defined by the shroud.
7. The apparatus of claim 6 , wherein the outlet ends of the plurality of powder injection nozzles extend through the inner wall at a location downstream of an eddy current generated by the plume.
8. The apparatus of claim 1 , wherein the shroud is configured to at least partially enclose an eddy current generated by the plume.
9. The apparatus of claim 1 , wherein at least one of a diameter, a length, and a radius of curvature of the inner wall are sized to correspond to a predetermined toroidal vortex generated by the plume.
10. The apparatus of claim 1 , wherein the thermal spray apparatus is a plasma gun and the plume is a plasma plume.
11. A plasma gun, comprising:
an outlet nozzle for emitting a plasma plume; and
an powder injection apparatus comprising a shroud removably connected to the outlet nozzle, wherein the shroud comprises:
a substantially smooth and continuous inner wall defining a bowl through which the plasma plume travels, and
at least one port in the inner wall structured and arranged to receive a powder injection nozzle that injects powder into the plasma plume.
12. The plasma gun of claim 11 , wherein the at least one port comprises a plurality of ports.
13. The plasma gun of claim 12 , further comprising a plurality of powder injection nozzles corresponding to the plurality of ports.
14. The plasma gun of claim 13 , wherein an outlet end of each respective one of the plurality of powder injection nozzles is substantially flush with the inner wall.
15. The plasma gun of claim 11 , wherein the shroud is configured to at least partially enclose an eddy current generated by the plasma plume.
16. The plasma gun of claim 11 , wherein at least one of a diameter, a length, and a radius of curvature of the inner wall are sized to correspond to a predetermined toroidal vortex generated by the plasma plume.
17. A method, comprising:
injecting powder into a plume using a shroud attachable to an outlet nozzle of a thermal spray apparatus, wherein the shroud comprises:
a substantially smooth and continuous inner wall defining a bowl through which a plume of the thermal spray apparatus travels, and
at least one port in the inner wall structured and arranged to receive a powder injection nozzle that injects powder into the plume.
18. A method, comprising:
shrouding an eddy current generated by a plume exiting an outlet nozzle of a thermal spray device, and
injecting powder into the plume downstream of the outlet nozzle through the eddy current wherein the shrouding comprises surrounding the eddy current with a shroud having a bowl shape that is substantially symmetric about a longitudinal axis of travel of the plume and that corresponds to a geometry of the eddy current and wherein the bowl shape is open in a direction of the plume travel.
19. The method of claim 18 , wherein:
the shrouding comprises positioning a shroud around the outlet nozzle; and
the injecting comprises guiding the powder through the shroud.
20. The apparatus of claim 1 , wherein the bowl is open in a direction of the plume travel.
21. The plasma gun of claim 11 , wherein the bowl is open in a direction of the plume travel.
22. The method of claim 17 , wherein the bowl is open in a direction of the plume travel.