Electrode for a Contact Start Plasma Arc Torch and Contact Start Plasma Arc Torch Employing Such Electrodes

• US 20120181257A1
• Filed: 01/06/2012
• Published: 07/19/2012
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Hypertherm Incorporated
• Original Assignee: Hypertherm Incorporated
• Inventors: Mather, Jonathan P., Sanders, Nicholas A., Lindsay, Jon W., Twarog, Peter, Shipulski, E. Michael, Duan, Zheng, Cook, David Jonathan
• Granted Patent: US 9,492,883 B2
• Time in Patent Office: Days
• US Class Current: 219/121.48
• CPC Class Codes: B23K 10/006 Control circuits therefor circuits for plasma torches H05H1/36
• CPC Class Codes: H05H 1/34 Details, e.g. electrodes, nozzles
• CPC Class Codes: H05H 1/3421 Transferred arc or pilot arc mode
• CPC Class Codes: H05H 1/3489 Means for contact starting

Abstract

A component for a contact start plasma arc torch is provided. The component includes a hollow body defining a channel with a longitudinal axis. The channel is capable of slideably receiving an electrode body along the longitudinal axis. The component includes a contact element disposed in the hollow body and includes a first surface and a second surface. The first surface is adapted to facilitate electrical communication with a power supply and the second surface is adapted to physically contact a surface of the electrode body when the plasma arc torch is operated in a transferred arc mode. In addition, the second surface is characterized by the absence of physical contact with the surface of the electrode body when the torch is operated in a pilot arc mode.

Claims

1. A component for a contact start plasma arc torch, the component comprising:

a hollow body defining a channel with a longitudinal axis, the channel capable of slideably receiving an electrode body along the longitudinal axis; and

a contact element disposed in the hollow body and includes a first surface and a second surface, the first surface facilitating electrical communication with a power supply and the second surface physically contacting a surface of the electrode body when the plasma arc torch is operated in a transferred arc mode, wherein the second surface is characterized by the absence of physical contact with the surface of the electrode body when the torch is operated in a pilot arc mode.

2. The component of claim 1 further comprising a swirl ring portion defining an exterior portion, an interior portion and one or more holes passing from the exterior portion to the interior portion for imparting a swirling motion to a fluid.

3. The component of claim 2, wherein the swirl ring portion is formed integrally with the hollow body.

4. The component of claim 1 wherein the hollow body comprises a swirl ring portion.

5. The component of claim 1 further comprising a resilient element contacting the electrode body when the electrode body is inserted into the channel, wherein the resilient element is configured to impart a separation force upon the electrode body.

6. The component of claim 5 wherein the resilient element is secured to the channel by a diametral interference fit.

7. The component of claim 5 wherein the resilient element is coupled to the contact element.

8. The component of claim 1 wherein the contact element is stationary.

9. The component of claim 1 wherein the channel comprises a shoulder for retraining a longitudinal movement of the contact element.

10. The component of claim 1 wherein an interior surface of the channel comprises an insulating material.

11. The component of claim 1 further comprising a power contact in electrical communication with the power supply and the first surface of the contact element.

12. A method of operating a contact start plasma arc torch, the method comprising:

slideably receiving an electrode body in a channel along a longitudinal axis, the channel being defined by a hollow body of a component of the plasma arc torch;

facilitating, when the plasma arc torch is operated in a transferred arc mode, i) electrical communication between a power supply and a first surface of a contact element disposed in the channel, and ii) physical contact between a second surface of the contact element and a surface of the electrode body; and

maintaining the absence of physical contact between the second surface of the contact element and the surface of the electrode body when the plasma arc torch is operated in a pilot arc mode.

13. The method of claim 12 further comprising imparting a swirling motion to a fluid by passing the fluid over one or more holes from an exterior surface to an interior surface of the component.

14. The method of claim 12 further comprising imparting a separation force upon the electrode body via a resilient element disposed between the second surface of the contact element and the surface of the electrode body.

15. The method of claim 14 further comprising coupling the resilient element to the contact element.

16. The method of claim 12 further comprising restraining a longitudinal movement of the contact element in the channel.

17. The method of claim 12 further comprising insulating an interior surface of the channel.

18. The method of claim 12 further comprising facilitating electrical communication between a power contact and the first surface of the contact element, wherein the power contact is in electrical communication with the power supply.

19. A component for a contact start plasma arc torch, the component comprising:

a hollow body defining a channel with a longitudinal axis, the channel capable of slideably receiving an electrode body along the longitudinal axis;

a first contact element disposed in the hollow body and including a first contact element surface and a second contact element surface, the first contact element surface facilitating electrical communication with a power supply; and

a supplemental contact element disposed in the hollow body and including a first supplemental contact element surface and a second supplemental contact element surface, the first supplemental contact element surface physically contacting the second contact element surface and the second supplemental contact element surface physically contacting a surface of the electrode body when the plasma arc torch is operated in a transferred arc mode.

20. The component of claim 19 further comprising a swirl ring portion defining an exterior portion, an interior portion and one or more holes passing from the exterior portion to the interior portion for imparting a swirling motion to a fluid.

22. The component of claim 19 further comprising a resilient element disposed between the second contact element surface and the first supplemental contact element surface in the channel, wherein the resilient element is configured to impart a separation force upon the supplemental contact element.

23. The component of claim 22 wherein the resilient element is secured to the channel by a diametral interference fit.

24. The component of claim 22 wherein the resilient element is coupled to at least one of the first contact element or the supplemental contact element.

25. The component of claim 19 wherein the first contact element is stationary.

26. The component of claim 19 wherein the supplemental contact element is translatable relative to the first contact element.

27. The component of claim 19 wherein an interior surface of the channel comprises an insulating material.

28. The component of claim 19 further comprising a power contact in electrical communication with the power supply and the first contact element surface of the first contact element.

21. The component of claim 21, wherein the swirl ring portion is formed integrally with the hollow body.

29. A method of operating a contact start plasma arc torch, the method comprising:

slideably receiving an electrode body in a channel along a longitudinal axis, the channel being defined by a hollow body of a component for the plasma arc torch;

facilitating electrical communication between a power supply and a first contact element surface of a first contact element disposed within the channel; and

facilitating, when the plasma arc torch is operated in a transferred arc mode, i) physical contact between a second contact element surface of the first contact element and a first supplemental contact element surface of a supplemental contact element disposed within the channel, and ii) physical contact between a second supplemental contact element surface of the supplemental contact element and a surface of the electrode body.

30. The method of claim 29 further comprising imparting a swirling motion to a fluid in the component by passing the fluid over one or more holes from an exterior surface to an interior surface of the component.

31. The method of claim 29 further comprising imparting a separation force upon the supplemental contact element via a resilient element disposed between the second contact element surface and the first supplemental contact element surface.

32. The method of claim 31 further comprising attaching the resilient element to at least one of the first contact element or the supplemental contact element.

33. The method of claim 29 further comprising translating the supplemental contact element relative to the first contact element during the transferred arc mode.

34. The method of claim 29 further comprising insulating an interior surface of the channel.

35. The method of claim 29 further comprising facilitating electrical communication between a power contact and the first contact element surface of the first contact element, wherein the power contact is in electrical communication with the power supply.

36. An assembly for a contact start plasma arc torch, the assembly comprising:

a hollow body defining a longitudinal axis, the hollow body capable of slideably receiving an electrode body along the longitudinal axis;

a contact element disposed in the hollow body and including a first surface and a second surface, the first surface capable of facilitating electrical communication with a power supply and the second surface physically contacting a surface of the electrode body when the electrode body is inserted into the hollow body; and

a resilient element connected to the contact element in the hollow body, the resilient element physically contacting the electrode body and imparting a separation force upon a surface of the electrode body when the electrode body is inserted into the hollow body.

37. The assembly of claim 36 wherein the resilient element passes substantially all of a pilot arc current to the electrode body when the torch is operated in a pilot arc mode.

38. The assembly of claim 36 further comprising a conductive element for passing substantially all of a pilot arc current to the electrode body when the torch is operated in a pilot arc mode.

39. The assembly of claim 36 wherein the assembly is a consumable component of the plasma arc torch.

40. The assembly of claim 36 wherein the assembly further includes a nozzle, a shield, a swirl ring or a retaining cap, or a combination thereof.

41. The assembly of claim 36 wherein the resilient element is in physical contact with the contact element.

42. An electrode for a contact start plasma arc torch, the electrode comprising:

an elongated electrode body formed of an electrically conductive material, the electrode body defining a longitudinal axis;

a contact element including a first surface and a second surface, the first surface facilitating electrical communication with a power supply and the second surface physically contacting a surface of the electrode body when the torch is operated in a transferred arc mode;

a resilient element between a proximal end of the electrode body and the contact element, the resilient element imparting a separation force between the second surface of the contact element and a surface of the electrode body; and

a conductive element for;

i) passing at least substantially all of a pilot arc current to the electrode body when the torch is operated in a pilot arc mode, or ii) passing at least substantially all of a transferred arc current to the electrode body when the torch is operated in a transferred arc mode, or a combination thereof.

43. The electrode of claim 42 further comprising an insulating material between the resilient element and the electrode body, or between the contact element and the resilient element, or a combination thereof, for preventing the resilient element from passing at least one of the pilot arc current or the transferred arc current to the electrode body.

44. The electrode of claim 42 wherein the resilient element is made of a non-conductive material.

45. The electrode of claim 42 wherein the conductive element is a wire in electrical communication with the contact element and the electrode body.

46. The electrode of claim 42 wherein the conductive element is a probe at least partially embedded in the electrode body, the probes is adapted to maintain physical contact with the contact element.

47. The electrode of claim 42 wherein the conductive element is a second resilient element coupled to at least a portion of the electrode body and in physical contact with the contact element.

48. The electrode of claim 42 wherein the conductive element is configured to pass substantially all of the pilot arc current and the transferred arc current.

49. The electrode of claim 42 further comprising an insulating material between the second surface of the contact element and the surface of the electrode body for preventing the transferred arc current from being passed from the contact element to the electrode body during the transferred arc mode.

50. An electrode for a contact start plasma arc torch in electrical communication with a power supply, the electrode comprising:

an elongated electrode body formed of an electrically conductive material, the electrode body defining a longitudinal axis; and

a resilient element adjacent to a proximal end of the electrode body, the resilient element capable of i) passing at least substantially all of a pilot arc current to the electrode body when the torch is operated in a pilot arc mode, and ii) passing at least substantially all of a transferred arc current to the electrode body when the torch is operated in a transferred arc mode.

51. A method of operating a contact start plasma arc torch, the method comprising:

providing an electrode for the plasma torch, the electrode comprising an electrode body defining a longitudinal axis, the electrode body including a proximal end adjacent to a resilient element;

passing at least substantially all of a pilot arc current generated by a power supply to the electrode body via the resilient element during a pilot arc operation of the torch; and

passing at least substantially all of a transferred arc current generated by the power supply to the electrode body via the resilient element during a transferred arc operations of the torch.