Nozzle for a liquid-cooled plasma torch, nozzle cap for a liquid-cooled plasma torch and plasma torch head comprising the same

1. A nozzle for a liquid cooled plasma torch, comprising:

a nozzle bore for the exit of a plasma gas beam at a nozzle tip;

a first section of said nozzle, said first section having an outer surface that is essentially cylindrical;

a second section of said nozzle connecting said first section to said nozzle tip, said second section having an outer surface that tapers essentially conically towards said nozzle tip;

at least one liquid supply groove, said at least one liquid supply groove extending over a part of said first section and over said second section of said outer surface of said nozzle towards said nozzle tip;

a single liquid return groove that is separate from said at least one liquid supply groove, said liquid return groove extending over said second section of said nozzle; and

another groove which is connected to said at least one liquid supply groove is disposed in said first section of said nozzle.

2. The nozzle of claim 1 , said liquid return groove also extending over a part of said outer surface of said first section of said nozzle.

3. The nozzle of claim 1 further comprising at least two liquid supply grooves.

4. The nozzle of claim 1 further comprising a middle point of said at least one liquid supply groove and a middle point of said liquid return groove, said middle points of said at least one liquid supply groove and of said liquid return groove are arranged offset by about 180° relative to each other around the circumference of said nozzle.

5. The nozzle of claim 1 , the width of said liquid return groove in the circumferential direction lies in the range from about 90° to 270°.

6. The nozzle of claim 1 , said another groove extends in the circumferential direction of said first section of said nozzle around the entire circumference.

7. The nozzle of claim 1 , said another groove extends in the circumferential direction of said first section of said nozzle over an angle in the range from about 60° to 300°.

8. The nozzle of claim 1 , said another groove extends in the circumferential direction of said first section of said nozzle over an angle in the range from about 90° to 270°.

9. The nozzle of claim 1 further comprising two liquid supply grooves.

10. The nozzle of claim 9 , said two liquid supply grooves being arranged around the circumference of said nozzle symmetrically to a straight line extending from the middle point of said liquid return groove at a right angle through the longitudinal axis of said nozzle.

11. The nozzle of claim 9 , the middle points of said two liquid supply grooves are arranged offset relative to each other around the circumference of said nozzle at an angle which lies in the range from about 30° to 180°.

12. The nozzle of claim 9 , the width of said liquid return groove in the circumferential direction lies in the range from about 120° to 270°.

13. The nozzle of claim 9 , said two liquid supply grooves are connected to each other in said first section of said nozzle.

14. The nozzle of claim 9 , said two liquid supply grooves are connected to each other in said first section of said nozzle by a groove.

15. The nozzle of claim 14 , said groove goes beyond one or both of said liquid supply grooves.

16. The nozzle of claim 14 , said groove extending in the circumferential direction of said first section of said nozzle around the whole circumference of said nozzle.

17. The nozzle of claim 14 , said groove extending in the circumferential direction of said first section of said nozzle over an angle in the range from about 60° to 300°.

18. The nozzle of claim 14 , said groove extending in the circumferential direction of said first section of said nozzle over an angle in the range from about 90° to 270°.

19. The nozzle of claim 1 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane.

20. The nozzle of claim 1 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane, said at least two recesses being arranged equidistantly around said inner circumference of said nozzle.

21. The nozzle of claim 1 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least three recesses in a radial plane.

22. The nozzle of claim 1 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane, said recesses being in semicircular form in said radial plane.

23. A nozzle for a liquid cooled plasma torch, comprising:

a nozzle bore for the exit of a plasma gas beam at a nozzle tip;

a first section of said nozzle, said first section having an outer surface that is essentially cylindrical;

a second section of said nozzle connecting said first section to said nozzle tip, said second section having an outer surface that tapers essentially conically towards said nozzle tip;

a single liquid supply groove, said liquid supply groove extending over a part of said first section and over said second section of said outer surface of said nozzle towards said nozzle tip;

at least one liquid return groove that is separate from said liquid supply groove, said at least one liquid return groove extending over said second section of said nozzle; and

another groove which is connected to said single liquid supply groove is disposed in said first section of said nozzle.

24. The nozzle of claim 23 , said at least one liquid return groove also extending over a part of said outer surface of said first section of said nozzle.

25. The nozzle of claim 23 further comprising at least two liquid return grooves.

26. The nozzle of claim 23 further comprising a middle point of said liquid supply groove and a middle point of said at least one liquid return groove, said middle points of said liquid supply groove and of said at least one liquid return groove are arranged offset by about 180° relative to each other around the circumference of said nozzle.

27. The nozzle of claim 23 , the width of said liquid supply groove in the circumferential direction lies in the range from about 90° to 270°.

28. The nozzle of claim 23 , said another groove extends in the circumferential direction of said first section of said nozzle over an angle in the range from about 60° to 300°.

29. The nozzle of claim 23 , said another groove extends in the circumferential direction of said first section of said nozzle over an angle in the range from about 90° to 270°.

30. The nozzle of claim 23 comprising two liquid return grooves.

31. The nozzle of claim 30 , said two liquid return grooves being, arranged around the circumference of said nozzle symmetrically to a straight line extending from the middle point of said liquid supply groove at a right angle through the longitudinal axis of said nozzle.

32. The nozzle of claim 30 , the middle points of said two liquid return grooves are arranged offset relative to each other around the circumference of the nozzle at an angle which lies in the range from about 30° to 180°.

33. The nozzle of claim 30 , the width of said liquid supply groove in the circumferential direction lies in the range from about 120° to 270°.

34. The nozzle of claim 30 , said two return grooves are connected to each other in said first section of said nozzle.

35. The nozzle of claim 30 , said two return grooves are connected to each other in said first section of said nozzle by a groove.

36. The nozzle of claim 35 , said groove goes beyond one or both of said liquid return grooves.

37. The nozzle of claim 35 , said groove extending in the circumferential direction of said first section of said nozzle over an angle in the range from about 60° to 300°.

38. The nozzle of claim 35 , said groove extending in the circumferential direction of said first section of said nozzle over an angle in the range from about 90° to 270°.

39. The nozzle of claim 23 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane.

40. The nozzle of claim 23 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane, said at least two recesses being arranged equidistantly amund said inner circumference of said nozzle.

41. The nozzle of claim 23 further comprising a nozzle cap, said nozzle cap having a inner surface tapering essentially conically, said inner surface including at least three recesses in a radial plane.

42. The nozzle of claim 23 further comprising a nozzle cap, said nozzle cap having an inner surface tapering essentially conically, said inner surface including at least two recesses in a radial plane, said recesses being in semicircular form in said radial plane.

43. The nozzle of claim 23 further comprising:

a nozzle holder for holding said nozzle;

a nozzle cap, said nozzle cap and said nozzle being positioned to form a cooling chamber, said cooling liquid chamber being connectable, via two bores respectively offset by about 60° to 180°, to at least one of a cooling liquid supply line and a cooling liquid return line; and

said nozzle holder being positioned to allow cooling liquid to be conveyed at least one of:

virtually perpendicular to the longitudinal axis of said plasma torch contacting said nozzle, and into said cooling liquid chamber; and

virtually perpendicular to the longitudinal axis of said plasma torch from the cooling liquid chamber into the nozzle holder.

44. The nozzle of claim 43 further comprising:

said nozzle includes at least one cooling liquid supply groove and at least one projecting region;

an inner surface of said nozzle cap, said inner surface having at least two recesses having openings facing said nozzle, said recesses respectively extending over a circular recess measure;

said at least one projecting region of said nozzle having a circular projecting region measure; and

said circular projecting region measure of said nozzle adjacent, in the circumferential direction, to said at least one cooling liquid supply groove and projecting outwardly in relation to said at least one cooling liquid supply groove, is at least as large as said circular recess measure.

45. The nozzle of claim 44 further comprising, said nozzle cap having at least two liquid supply grooves.

46. The nozzle of claim 44 further comprising, said inner surface of said nozzle cap having at least three recesses.

47. The nozzle of claim 43 further comprising, said two bores each extending essentially parallel to the longitudinal axis of said plasma torch head.

48. The nozzle of claim 43 further comprising, said bores for said cooling liquid supply line and said cooling liquid return line are arranged offset by 180°.

49. The nozzle of claim 43 further comprising:

a section of said nozzle cap having a plurality of recesses, the circular measure of said section of said nozzle cap between said recesses being at least one of:

as a maximum half the size of the minimum circular measure of said liquid return groove; and

as a maximum the minimum circular measure of at least one of said liquid supply groove and said nozzle.