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1. WO2020112929 - ELECTRODE FOR A PLASMA GUN

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

WHAT IS CLAIMED:

1. A cathode for a plasma gun, comprising:

a main body having a first end and a second end; and

a protrusion extending from the first end,

wherein the protrusion has an emission zone diameter that is less than about 4 mm.

2. The cathode of claim 1, wherein the protrusion is one of a reduced diameter or

reduced cross-section projection, is a forwardmost portion of the main body and has an axial length less than about 2 mm.

3. The cathode of claim 1, wherein the protrusion has at least one of a smaller diameter or smaller cross-section than any other portion of the main body.

4. The cathode of claim 1, wherein the first end is a first material and the second end is a second material.

5. The cathode of claim 1, wherein the first and second ends are different materials.

6. The cathode of claim 1, wherein the protrusion projects from a flat surface of the first end.

7. The cathode of claim 1, wherein the protrusion projects from a conical surface of the first end.

8. The cathode of claim 1, wherein the protrusion projects from a dome shaped surface of the first end.

9. The cathode of claim 1, wherein the protrusion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm and less than about 2 mm from a surrounding surface of the first end.

10. The cathode of claim 2, wherein the first material is tungsten or doped tungsten.

11. The cathode of claim 1, wherein the first end of the cathode is an emission end.

12. The cathode of claim 4, wherein the second material is copper.

13. The cathode of claim 1, wherein the cathode is water cooled.

14. The cathode of claim 1, wherein the protrusion is coaxially aligned with a center axis of the main body.

15. A method of using the cathode of claim 1, comprising:

mounting the cathode inside a plasma gun; and

generating an arc discharge via the protrusion.

16. A method of using the cathode of claim 1, wherein the protrusion limits a size of an emission zone or spray area.

17. A method of using the cathode of claim 1, wherein the protrusion increases current density in an emission zone.

18. An electrode for use in a plasma gun comprising:

a tungsten body having a first end and a second end, wherein the first end has a centrally located arc discharge extension of reduced diameter or cross-section.

19. An electrode for use in a plasma gun comprising:

a tungsten body having a first end and a second end, wherein the first end has an arc discharge extension of reduced diameter or cross-section and forming a forwardmost portion of the main body.

20. A cathode for a plasma gun, comprising:

a tungsten body having a first end and a second end; and

a reduced-diameter tungsten portion projecting or extending from an end surface of the first end.

21. The cathode of claim 20, wherein the protrusion has a base diameter of between about 0.5 mm and about 2 mm and projects from the end surface by:

at least about 0.5 mm; and

no more that 2 or 3 times a diameter of the protrusion.

22. The cathode of claim 20, wherein the first and second ends are arranged on a one- piece integrally formed member.

23. The cathode of claim 20, wherein the reduced-diameter portion projects from a flat end surface of the first end.

24. The cathode of claim 20, wherein the reduced-diameter portion projects from a conical end surface of the first end.

25. The cathode of claim 20, wherein the reduced-diameter portion projects from a dome shaped end surface of the first end.

26. An electrode for use in a plasma gun comprising:

a tungsten main body having an emission end and a mounting end, wherein the emission end has an arc discharge extension of reduced diameter or cross-section that forms a forwardmost portion of the main body.

27. A cathode for a plasma gun, comprising:

a tungsten body having an arc discharge end and a mounting end; and

a reduced-diameter portion projecting or extending from an end surface of the arc discharging end.

28. The cathode of claim 27, wherein the reduced-diameter or reduced cross-section

portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced- diameter or reduced cross-section portion.

29. A cathode for a plasma gun, comprising:

a tungsten body having an arc discharge end and a mounting end; and

a reduced-diameter portion tapered or pointed projecting or extending from a larger diameter end surface of the arc discharging end.

30. The cathode of claim 29, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

31. A cathode for a plasma gun, comprising:

a tungsten body having an arc discharge end and a mounting end; and

a reduced-diameter semi-spherical or bulbous portion projecting or extending from an end surface of the arc discharging end.

32. The cathode of claim 31, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

33. A cathode for a plasma gun, comprising:

a tungsten body having an arc discharge end and a mounting end; and

a reduced-diameter stepped- shaped portion projecting or extending from an end surface of the arc discharging end.

34. The cathode of claim 33, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

35. A cathode for a plasma gun, comprising:

a tungsten body having an arc discharge end and a threaded mounting end; and a reduced-diameter ring-shaped portion projecting or extending from an end surface of the arc discharging end.

36. The cathode of claim 35, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

37. A cathode for a plasma gun, comprising:

a tungsten body comprising:

at least one generally cylindrical section;

an arc discharge end;

a mounting end; and

a single, axially-oriented and centrally disposed, reduced-diameter portion projecting or extending from an end surface of the arc discharging end.

38. The cathode of claim 37, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

39. A cathode for a plasma gun, comprising:

a one-piece metal body comprising:

at least one generally cylindrical section;

an arc discharge end;

a mounting end; and

a single, axially-oriented and centrally disposed, reduced-diameter portion that is a forwardmost portion of the arc discharging end.

40. The cathode of claim 39, wherein the reduced-diameter portion is between about 0.5 mm and about 2.0 mm in diameter and projects at least 0.5 mm from a surface and/or no more that 2 or 3 times a diameter of the reduced-diameter portion.

41. A method of modifying a cathode of a plasma gun, comprising:

removing the cathode from the plasma gun;

performing metal removing or machining on the cathode in order to shape the forwardmost or arc discharging end so as to have a single centrally disposed and axially oriented protrusion; and

reinstalling the cathode on the plasma gun.

42. The method of claim 41, further comprising operating the plasma gun with a power during the application of a coating material, said power being a lower power compared to a power used in operating the plasma gun before the cathode is modified.