Systems and Methods for Separating Consumables Under Pressure in a Plasma Arc Torch

1 . A contact start liquid-cooled plasma arc cutting torch comprising:

a translatable liquid-cooled electrode comprising an electrode body defining a proximal end and a distal end along a longitudinal axis of the electrode body, the electrode body including a coolant cavity with a distal internal coolant surface disposed at the distal end of the electrode body, the coolant cavity configured to receive at least a portion of a coolant tube of the torch for directing a liquid coolant flow distally through the coolant tube within the coolant cavity and toward the distal internal coolant surface of the electrode, wherein the distal internal coolant surface is shaped to substantially redirect the liquid coolant flow proximally over an exterior surface of the coolant tube within the coolant cavity;

a nozzle disposed about the distal end of the electrode body; and

a multi-piece cathode disposed about the proximal end of the electrode body, the cathode including:

a first body shaped to matingly engage the electrode, and

a second body shaped to matingly engage the torch, wherein the first body slidingly engages the second body such that the first body and the electrode are axially translatable relative to the second body along the longitudinal axis.

2 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , wherein the axial translation of the electrode relative to the second body biases the electrode relative to the nozzle at the distal end of the electrode.

3 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , further comprising a gas input port for receiving and supplying a biasing gas to the torch, wherein the biasing gas is adapted to create a blowback pressure on the first body of the cathode to axially translate the first body into an abutting position with the second body, thereby axially translating the electrode away from the nozzle.

4 . The contact start liquid-cooled plasma arc cutting torch of claim 3 , wherein the liquid coolant flow in the coolant cavity of the electrode body is adapted to create a forward biasing pressure on the electrode to axially translate the electrode toward the nozzle, thereby axially translating the first body away from the second body of the cathode.

5 . The contact start liquid-cooled plasma arc cutting torch of claim 4 , wherein the forward biasing pressure is greater than the blowback pressure.

6 . The contact start liquid-cooled plasma arc cutting torch of claim 5 , wherein a lateral surface of the first body directly exposed to the blow-back pressure has a surface area that is greater than a surface area of the internal coolant surface of the electrode directly exposed to the forward biasing pressure, the lateral surface of the first body and the internal coolant surface of the electrode being substantially orthogonal to the longitudinal axis.

7 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , further comprising a sealed pressurization chamber having a first portion defined by a blowback flange of the first body of the cathode.

8 . The contact start liquid-cooled plasma arc cutting torch of claim 7 , wherein the blowback flange includes a first surface exposed to a biasing gas flow for urging the first body into an abutting position relative to the second body.

9 . The contact start liquid-cooled plasma arc cutting torch of claim 8 , wherein the sealed pressurization chamber is pressurized by the biasing gas received from a gas port disposed in the torch.

10 . The contact start liquid-cooled plasma arc cutting torch of claim 8 , wherein a pressure of the liquid coolant flow against the distal internal coolant surface of the electrode is greater than a pressure of the biasing gas flow.

11 . The contact start liquid-cooled plasma arc cutting torch of claim 10 , wherein the pressure of the liquid coolant flow is about 40% great that the pressure of the biasing gas flow.

12 . The contact start liquid-cooled plasma arc cutting torch of claim 8 , wherein a surface area of the first surface of the blowback flange is greater than a surface area of the distal internal coolant surface.

13 . The contact start liquid-cooled plasma arc cutting torch of claim 7 , wherein the sealed pressurization chamber has a second portion defined by one of a swirl ring or a plasma chamber cover.

14 . The contact start liquid-cooled plasma arc cutting torch of claim 13 , wherein the plasma chamber cover and the swirl ring form a unitary structure.

15 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , wherein the axial translation of the electrode is independent of a plasma gas flow through the torch.

16 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , wherein the cathode includes a set of one or more anti-rotation features located between the first and second bodies to prevent a radial movement of the first and second bodies relative to each other.

17 . The contact start liquid-cooled plasma arc cutting torch of claim 16 , wherein the set of one or more anti-rotation features comprises a set of one or more male shoulder sections of the first body and a set of one or more female shoulder sections of the second body, the male shoulder sections are configured to matingly engage the corresponding female shoulder sections.

18 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , wherein the first body of the cathode includes a set of one or more threads to matingly engage the electrode.

19 . The contact start liquid-cooled plasma arc cutting torch of claim 1 , further comprising an electrical contact disposed between the first and second bodies of the cathode.

20 . The contact start liquid-cooled plasma arc cutting torch of claim 19 , wherein the electrical contact comprises a canted coil spring.

21 . The contact start liquid-cooled plasma arc cutting torch of claim 19 , wherein the electrical contact is configured to pass substantially all of a pilot arc current between the first and second bodies during a pilot arc mode of torch operation.

22 . A multi-piece torch cathode for a contact start liquid-cooled plasma arc torch, the multi-piece torch cathode comprising:

a first body including a cavity configured to receive and matingly engage an electrode; and

a second body disposed within the torch, wherein the first body slidingly engages the first body and axially translates relative to the second body during an operation of the plasma arc torch.

23 . The multi-piece torch cathode of claim 22 , wherein the axial translation of the first body relative to the second body drives an axial translation of the electrode relative to the second body, thereby biasing the electrode relative to a nozzle of the plasma arc torch at the distal end of the electrode.

24 . The multi-piece torch cathode of claim 23 , wherein the axial translation of the electrode is independent of a plasma gas flow through the torch.

25 . The multi-piece torch cathode of claim 22 , wherein the first body includes a blowback flange having a blowback surface oriented substantially perpendicular to a longitudinal axis of the torch, the blowback flange adapted to be in fluid communication with a biasing gas, the biasing gas adapted to exert a blowback pressure on the blowback surface to translate the first body into an abutting position with the second body.

26 . The multi-piece torch cathode of claim 25 , wherein the blowback pressure is less than a blow-forward pressure of the torch.

27 . The multi-piece torch cathode of claim 26 , wherein a surface area of the blowback surface is greater than a surface area of a surface of the electrode against which the blow-forward pressure directly exerts.

28 . The multi-piece torch cathode of claim 22 , further comprising a set of one or more anti-rotation features located between the first and second bodies to prevent a radial movement of the first and second bodies relative to each other.

29 . The multi-piece torch cathode of claim 28 , wherein the set of one or more anti-rotation features comprises a set of one or more male shoulder sections of the first body and a set of one or more female shoulder sections of the second body, the male shoulder sections are configured to matingly engage the corresponding female shoulder sections.

30 . The multi-piece torch cathode of claim 22 , further comprising a set of one or more threads disposed on the first body to enable the mating engagement of the first body with the electrode.

31 . The multi-piece torch cathode of claim 22 , further comprising a dynamic electrical contact disposed between the first and second bodies.

32 . The multi-piece torch cathode of claim 31 , wherein the dynamic electrical contact comprises a canted coil spring.

33 . The multi-piece torch cathode of claim 31 , wherein the dynamic electrical contact is configured to pass substantially all of a pilot arc current between the first and second bodies during a pilot arc mode of torch operation.

34 . A method for contact starting a liquid-cooled plasma arc torch comprising an electrode, a nozzle disposed about a distal end of the electrode, and a multi-piece cathode disposed about a proximal end of the electrode, the method comprising:

supplying a coolant flow to the electrode, the coolant flow is adapted to exert a first pressure on a surface of the electrode thereby biasing the electrode into physical contact with the nozzle;

establishing a torch current flow between the electrode and the nozzle that is a pilot current flow;

supplying a plasma cutting gas to a plenum of the torch;

supplying a biasing gas to a sealed pressurization chamber of the torch, the biasing gas adapted to create a second pressure in the sealed pressurization chamber that biases the electrode away from the nozzle thereby initiating a plasma arc using the plasma cutting gas in the plenum; and

transferring the torch current flow from the nozzle to the workpiece while cutting the workpiece with the plasma arc.

35 . The method of claim 34 , wherein the biasing of the electrode into physical contact with or away from the nozzle is independent of the plasma cutting gas flow through the torch.

36 . The method of claim 34 , wherein the sealed pressurization chamber is located proximal to the plenum.

37 . The method of claim 34 , wherein the coolant flow is supplied to the electrode via a coolant tube inserted into a cavity of the electrode, the cavity comprising a distal coolant surface adapted to be directly exposed to the first pressure.

38 . The method of claim 37 , wherein a portion of the sealed pressurization chamber is defined by a biasing flange of a first body of the multi-piece cathode, the first body fixedly attached to the electrode and translatable relative to a stationary second body of the cathode, the first body disposed distal to the second body.

39 . The method of claim 38 , further comprising exerting the second pressure against a biasing surface of the biasing flange of the first body to translate the first body proximally into physical contact with the first body, thereby translating the electrode proximally away from the nozzle.

40 . The method of claim 39 , wherein a first area of the distal coolant surface is smaller than a second area of the biasing surface of the biasing flange.

41 . The method of claim 40 , wherein the first pressure of the coolant flow against the distal coolant surface is greater than the second pressure of the biasing gas against the biasing surface.

42 . The method of claim 38 , further comprising ramping down the supply of the biasing gas for operating the torch to enable the first pressure exerted on the electrode to translate the first body away from the second body of the cathode and allow the electrode to physically contact the nozzle in preparation for a next start of the torch.

43 . The method of claim 42 , further comprising passing substantially all of the pilot current flow via a dynamic electrical contact located between the first and second bodies of the cathode.

44 . A contact start liquid-cooled plasma arc cutting torch comprising:

a consumable torch head including a nozzle, an electrode, a coolant tube and a cathode; and

a receptacle connected to a proximal end of the torch head, the receptacle configured to controllably supply a liquid coolant and one or more gases to the cutting head, the receptacle comprising:

a coolant valve interface for providing a supply of the liquid coolant to the coolant tube, the liquid coolant configured to cool the torch head while exerting a forward pressure configured to bias the electrode toward the nozzle;

a first gas valve for regulating a supply of a plasma cutting gas to a plenum located between the electrode and the nozzle of the torch head, the plasma cutting gas adapted to create a plasma arc for cutting a workpiece; and

a second gas valve for regulating a supply of a biasing gas to a pressurization chamber located adjacent to the cathode of the torch head, the biasing gas adapted to create a backward pressure in the pressurization chamber to bias the electrode away from the nozzle.

45 . The contact start liquid-cooled plasma arc cutting torch of claim 44 , wherein the coolant valve interface is adapted to supply the liquid coolant to the coolant tube during both a transferred arc mode and a pilot arc mode for operating the torch.

46 . The contact start liquid-cooled plasma arc cutting torch of claim 44 , wherein the second gas valve for regulating the biasing gas supply is adapted to be closed or ramped down for at least a portion of a time duration when operating the torch.

47 . The contact start liquid-cooled plasma arc cutting torch of claim 44 , further comprising a volume disposed in the receptacle for storing a radio-frequency identification (RFID) tag, wherein the RFID tag is configured to store at least one of consumable identification information, consumable usage history or process parameters.

48 . The contact start liquid-cooled plasma arc cutting torch of claim 44 , wherein the biasing gas comprises a nitrogen gas.