Dual mode plasma arc torch

• US 6,717,096 B2
• Filed: 02/26/2002
• Issued: 04/06/2004
• Est. Priority Date: 02/27/2001
• Status: Expired due to Term

• Current Assignee: Victor Equipment Co. (Enovis Corp.)
• Original Assignee: Thermal Dynamics Corporation (Enovis Corp.)
• Inventors: Hewett, Roger W., Jones, Joseph P., Chen, Shiyu, Rogers, Fred, Horner-Richardson, Kevin D.
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US10/083,029
• Publication Number:
  US 20020117482A1
• Time in Patent Office: 770 Days
• Field of Search: 219/121.54, 219/121.57, 219/121.39, 219/121.5, 219/121.51, 219/121.52, 219/74, 219/75, 219/121.59, 219/121.48
• US Class Current: 219/121.48
• CPC Class Codes: H05H 1/34 Details, e.g. electrodes, nozzles
• CPC Class Codes: H05H 1/3468 Vortex generators
• CPC Class Codes: H05H 1/3489 Means for contact starting

Abstract

A dual mode plasma arc torch is provided that preferably comprises a start cartridge disposed between an electrode and a tip. In one form, the start cartridge comprises an initiator that is in electrical contact with the electrode and that is resiliently biased into contact with the tip, such that when the plasma arc torch is in a contact start mode, the initiator is movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip. Further, when the plasma arc torch is in a high frequency start mode, the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip. In other forms, a contact start torch is provided that is operable under high frequency, and conversely, a high frequency start torch is provided that is operable under low voltage.

Claims

1. A plasma arc torch comprising:

an electrode;

a tip; and

a start cartridge disposed between the electrode and the tip, the start cartridge comprising an initiator in electrical contact with the electrode and resiliently biased into contact with the tip,

wherein when the plasma arc torch is in a contact start mode, the initiator is movable to separate from the tip and establish a pilot arc between the initiator and the tip, and

when the plasma arc torch is in a high frequency start mode, the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip.

2. The plasma arc torch according to claim 1, wherein the start cartridge further comprises:

a cartridge assembly;

a biasing member disposed within the cartridge assembly; and

the initiator disposed adjacent the biasing member and within the cartridge assembly,

wherein the biasing member biases the initiator into contact with the tip.

3. The plasma arc torch according to claim 2, wherein the cartridge assembly further comprises a cartridge body and a tip seat secured to a distal portion of the cartridge body.

4. The plasma arc torch according to claim 2, wherein the biasing member is a coil spring.

5. A plasma arc torch comprising:

an electrode;

a tip; and

at least one of a contact start cartridge for a contact start mode and a high frequency start cartridge for a high frequency start mode, the start cartridges being disposed between the electrode and the tip, and the contact start cartridge comprising an initiator in electrical contact with the electrode and resiliently biased into contact with the tip,

wherein when the plasma arc torch is in a contact start mode, the initiator is movable to separate from the tip and establish a pilot arc between the initiator and the tip, and

when the plasma arc torch is in a high frequency start mode, the high frequency start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip.

6. The plasma arc torch according to claim 5, wherein the high frequency start cartridge further comprises:

a plurality of vent holes that provide gas flow to cool the electrode.

7. The plasma arc torch according to claim 6, wherein the vent holes further comprise outer vent holes and inner vent holes such that a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes.

8. The plasma arc torch according to claim 6, wherein the vent holes are offset from a center of the high frequency start cartridge.

9. The plasma arc torch according to claim 6, wherein the high frequency start cartridge further comprises a plurality of vent passages in communication with the vent holes to vent the gas from within the start cartridge.

10. The plasma arc torch according to claim 5, wherein the high frequency start cartridge further comprises an internal collar to isolate a venting chamber from a plasma chamber.

11. The plasma arc torch according to claim 5, wherein the high frequency start cartridge further comprises:

a cartridge body defining a distal end; and

a tip seat secured to the distal end of the cartridge body,

wherein the cartridge body is in electrical contact with the electrode and the tip seat insulates the cartridge body from the tip.

12. The plasma arc torch according to claim 5, wherein the high frequency start cartridge further comprises:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the tip seat is in electrical contact with the tip and the cartridge body insulates the tip seat from the electrode.

13. A plasma arc torch comprising:

an electrode;

a tip; and

a start cartridge disposed between the electrode and the tip, the start cartridge comprising a plurality of vent holes that provide gas flow to cool the electrode,

wherein the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip when the plasma arc torch is in a high frequency start mode.

14. The plasma arc torch according to claim 13, wherein the vent holes further comprise outer vent holes and inner vent holes such that a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes.

15. The plasma arc torch according to claim 13, wherein the vent holes are offset from a center of the start cartridge.

16. The plasma arc torch according to claim 13, wherein the start cartridge further comprises a plurality of vent passages in communication with the vent holes to vent the gas from within the start cartridge.

17. The plasma arc torch according to claim 13, wherein the start cartridge further comprises an internal collar to isolate a venting chamber from a plasma chamber.

18. The plasma arc torch according to claim 13, wherein the start cartridge further comprises:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the cartridge body is in electrical contact with the electrode and the tip seat insulates the cartridge body from the tip.

19. The plasma arc torch according to claim 13, wherein the start cartridge further comprises:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the tip seat is in electrical contact with the tip and the cartridge body insulates the tip seat from the electrode.

20. A start cartridge for use in a high frequency start plasma arc torch, the start cartridge providing separation and electrical isolation between an electrode and a tip in the plasma arc torch, the start cartridge further comprising a plurality of vent holes that provide gas flow to cool the electrode.

21. The start cartridge according to claim 20, wherein the vent holes further comprise outer vent holes and inner vent holes such that a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes.

22. The start cartridge according to claim 20, wherein the vent holes are offset from a center of the start cartridge.

23. The start cartridge according to claim 20, wherein the start cartridge further comprises a plurality of vent passages in communication with the vent holes to vent the gas from within the start cartridge.

24. The start cartridge according to claim 20, wherein the start cartridge further comprises an internal collar to isolate a venting chamber from a plasma chamber within the plasma arc torch.

25. The start cartridge according to claim 20 further comprising:

a cartridge body defining a distal end; and

a tip seat secured to the distal end of the cartridge body,

wherein the cartridge body is in electrical contact with the electrode and the tip seat insulates the cartridge body from the tip.

26. The start cartridge according to claim 20 further comprising:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the tip seat is in electrical contact with the tip and the cartridge body insulates the tip seat from the electrode.

27. A start cartridge for use in a high frequency start plasma arc torch, the start cartridge providing separation and electrical isolation between an electrode and a tip in the plasma arc torch, comprising:

a plurality of vent holes defining outer vent holes and inner vent holes; and

an internal collar,

wherein the vent holes provide gas flow to cool the electrode, and a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes and the internal collar isolates a venting chamber from a plasma chamber within the plasma arc torch.

28. A plasma arc torch comprising:

an electrode;

a tip; and

a start cartridge disposed between the electrode and the tip, the start cartridge comprising;

a cartridge body;

a tip seat secured to a distal end of the cartridge body;

a biasing member disposed within the cartridge body; and

an initiator in electrical contact with the electrode and biased into contact with the tip by the biasing member,

wherein when the plasma arc torch is in a contact start mode, the initiator is movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip, and

when the plasma arc torch is in a high frequency start mode, the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip.

29. The plasma arc torch according to claim 28, wherein the biasing member is a coil spring.

30. A plasma arc torch comprising:

an electrode;

a tip; and

at least one of a contact start cartridge for a contact start mode and a high frequency start cartridge for a high frequency start mode, the start cartridges being disposed between the electrode and the tip, the contact start cartridge comprising;

a cartridge body;

a tip seat secured to a distal end of the cartridge body;

a biasing member disposed within the cartridge body; and

an initiator in electrical contact with the electrode and biased into contact with the tip by the biasing member,

wherein when the plasma arc torch is in a contact start mode, the initiator is movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip, and

when the plasma arc torch is in a high frequency start mode, the start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip.

31. The plasma arc torch according to claim 30, wherein the high frequency start cartridge further comprises:

a plurality of vent holes that provide gas flow to cool the electrode.

32. The plasma arc torch according to claim 31, wherein the vent holes further comprise outer vent holes and inner vent holes such that a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes.

33. The plasma arc torch according to claim 31, wherein the vent holes are offset from a center of the high frequency start cartridge.

34. The plasma arc torch according to claim 31, wherein the high frequency start cartridge further comprises a plurality of vent passages in communication with the vent holes to vent the gas from within the start cartridge.

35. The plasma arc torch according to claim 30, wherein the high frequency start cartridge further comprises an internal collar to isolate a venting chamber from a plasma chamber.

36. The plasma arc torch according to claim 30, wherein the high frequency start cartridge further comprises:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the cartridge body is in electrical contact with the electrode and the tip seat insulates the cartridge body from the tip.

37. The plasma arc torch according to claim 30, wherein the high frequency start cartridge further comprises:

a cartridge body; and

a tip seat secured to a distal end of the cartridge body,

wherein the tip seat is in electrical contact with the tip and the cartridge body insulates the tip seat from the electrode.

38. A plasma arc torch comprising:

an electrode;

a tip; and

at least one of a contact start cartridge for a contact start mode and a high frequency start cartridge for a high frequency start mode, the start cartridges being disposed between the electrode and the tip,

the contact start cartridge comprising;

a cartridge body;

a tip seat secured to a distal end of the cartridge body;

a biasing member disposed within the cartridge body; and

an initiator in electrical contact with the electrode and biased into contact with the tip by the biasing member; and

the high frequency start cartridge comprising a plurality of vent holes defining outer vent holes and inner vent holes, an internal collar, and vent passages such that the vent holes and vent passages provide gas flow to cool the electrode, and a velocity of the gas is increased as the gas flows from the outer vent holes to the inner vent holes, and the internal collar isolates a venting chamber from a plasma chamber within the plasma arc torch,

wherein when the plasma arc torch is in a contact start mode, the initiator is movable against the resilient bias to separate from the tip and establish a pilot arc between the initiator and the tip, and

when the plasma arc torch is in a high frequency start mode, the high frequency start cartridge spaces the tip from the electrode such that a pilot arc is established between the electrode and the tip.

39. A contact start torch modified for operation with a high frequency power supply comprising:

a torch head;

an electrode electrically connected to a cathode within the torch head;

a tip electrically connected to an anode within the torch head; and

a dielectric standoff,

wherein the dielectric standoff is sized such that the contact start torch is operable under high frequency.

40. The contact start torch according to claim 39, wherein the electrode is translatable relative to the tip to initiate a pilot arc between the electrode and the tip.

41. The contact start torch according to claim 39, wherein the tip is translatable relative to the electrode to initiate a pilot arc between the electrode and the tip.

42. The contact start torch according to claim 39, wherein the electrode and the tip are translatable relative to each other to initiate a pilot arc between the electrode and the tip.

43. A contact start torch modified for operation with a high frequency power supply comprising:

a torch head;

an electrode electrically connected to a cathode within the torch head;

a tip electrically connected to an anode within the torch head

a movable element disposed between the electrode and the tip that moves to create a pilot arc between the electrode and the tip; and

a dielectric standoff disposed between the cathode and the anode,

wherein the dielectric standoff is sized such that the contact start torch is operable under high frequency.

44. A high frequency plasma arc torch modified for operation with a low voltage power supply comprising:

a torch head;

an electrode electrically connected to a cathode within the torch head; and

a tip electrically connected to an anode within the torch head;

wherein either one of both of the electrode and the tip are movable and the plasma arc torch operates under low voltage.

45. A high frequency plasma arc torch modified for operation with a low voltage power supply comprising:

a torch head;

an electrode electrically connected to a cathode within the torch head;

a movable third element disposed between the electrode and the tip; and

a tip electrically connected to an anode within the torch head;

wherein the movable third element is movable between the electrode and the tip to form a pilot arc, and the plasma arc torch operates under low voltage.

46. A method of initiating a pilot arc in a plasma arc torch, the method comprising the steps of:

disposing a start cartridge comprising an initiator between an electrode and a tip;

biasing the initiator into contact with the tip;

providing a source of gas and electric power; and

directing at least a portion of the gas to overcome the bias to separate the initiator from the tip,

wherein the pilot arc is drawn between the initiator and the tip as the bias is overcome when the plasma arc torch is in a contact start mode, and

the pilot arc is drawn between the electrode and the tip as the start cartridge spaces the electrode from the tip when the plasma arc torch is in a high frequency start mode.

47. The method of claim 46 further comprising the step of venting at least a portion of the gas used to overcome the bias through the start cartridge when the plasma arc torch is in the contact start mode.

48. The method according to claim 47 further comprising the step of venting the gas from the start cartridge through head vent holes in a torch head.

49. A method of operating a plasma arc torch in one of a contact start mode and a high frequency start mode, the method comprising the steps of:

disposing a contact start cartridge comprising an initiator between an electrode and a tip when the plasma arc torch is in the contact start mode;

biasing the initiator into contact with the tip;

providing a source of gas and electric power; and

directing at least a portion of the gas to overcome the bias to separate the initiator from the tip,

wherein the pilot arc is drawn between the initiator and the tip as the bias is overcome when the plasma arc torch is in the contact start mode, and

disposing a high frequency start cartridge between an electrode and a tip when the plasma arc torch is in the high frequency start mode,

wherein the pilot arc is drawn between the electrode and the tip as the start cartridge spaces the electrode from the tip in the high frequency start mode.

50. The method according to claim 49 further comprising the step of venting at least a portion of the gas used to overcome the bias through the contact start cartridge when the plasma arc torch is in the contact start mode.

51. The method according to claim 50 further comprising the step of venting the gas from the contact start cartridge through head vent holes in a torch head.

52. The method according to claim 49 further comprising the step of venting a portion of the gas through the start cartridge during operation to cool an electrode disposed within the plasma arc torch.

53. A method of operating a plasma arc torch in a high frequency mode, the method comprising the steps of:

disposing a start cartridge between an electrode and a tip;

providing a source of gas and electric power; and

venting a portion of the gas through the start cartridge during operation to cool an electrode disposed within the plasma arc torch,

wherein a pilot arc is drawn between the electrode and the tip as the start cartridge spaces the electrode from the tip in the high frequency start mode.

54. A method of operating a contact start plasma arc torch modified to operate under high frequency, the method comprising the steps of:

providing a sufficient dielectric standoff between a cathode body and an anode body within the plasma arc torch sufficient to operate under high frequency; and

providing a source of gas and electric power at a high frequency,

wherein the contact start plasma arc torch is operable in a high frequency start mode with the dielectric standoff.

55. A method of operating a high frequency start plasma arc torch modified to operate under low voltage, the method comprising the steps of:

providing a movable element to the high frequency start plasma arc torch;

providing a source of gas and electric power at low voltage; and

moving the movable element such that a pilot arc is generated,

wherein the high frequency start plasma arc torch is operable under low voltage.

56. The method according to claim 55, wherein the movable element is an electrode.

57. The method according to claim 55, wherein the movable element is a tip.

58. The method according to claim 55, wherein the movable element is a movable third element.