Contact start plasma torch
First Claim
1. A contact start plasma torch comprising:
- a cathode body adapted for electrical communication with the negative side of a power supply;
an anode body adapted for electrical communication with the positive side of the power supply;
a primary gas flow path for directing working gas from a source of working gas through the torch; and
a conductive element constructed of an electrically conductive material and being free from fixed connection with the cathode body and the anode body;
the torch being operable between an idle mode in which the conductive element provides an electrically conductive path between the cathode body and the anode body and a pilot mode in which a pilot arc formed between the conductive element and at least one of said cathode body and said anode body is adapted for initiating operation of the torch by exhausting working gas in the primary gas flow path from the torch in the form of an ionized plasma.
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Accused Products
Abstract
A contact start plasma torch and method of starting the torch includes a negatively charged cathode body and a positively charged anode body. A conductive element in the torch is constructed of an electrically conductive material and is free from fixed connection with the cathode body and the anode body. The torch is operable between an idle mode wherein the conductive element provides an electrically conductive path between the cathode body and the anode body and an pilot mode wherein a pilot arc is formed between the conductive element and at least one of the cathode body and the anode body. The pilot arc is blown by working gas flowing through the torch toward an exit orifice of the torch whereby 10) the working gas is exhausted from the torch in the form of an ionized plasma.
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Citations
65 Claims
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1. A contact start plasma torch comprising:
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a cathode body adapted for electrical communication with the negative side of a power supply;
an anode body adapted for electrical communication with the positive side of the power supply;
a primary gas flow path for directing working gas from a source of working gas through the torch; and
a conductive element constructed of an electrically conductive material and being free from fixed connection with the cathode body and the anode body;
the torch being operable between an idle mode in which the conductive element provides an electrically conductive path between the cathode body and the anode body and a pilot mode in which a pilot arc formed between the conductive element and at least one of said cathode body and said anode body is adapted for initiating operation of the torch by exhausting working gas in the primary gas flow path from the torch in the form of an ionized plasma. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A contact start plasma torch of the type having a primary gas flow path for directing a working gas through the torch whereby working gas is exhausted from the torch in the form of an ionized plasma, said torch comprising:
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an electrode having a longitudinally extending side surface and a bottom surface;
a tip surrounding the electrode in spaced relationship therewith to at least partially define the primary gas flow path of the torch for directing working gas through the torch in a downstream direction, the tip having a central exit orifice in fluid communication with the primary gas flow path for exhausting working gas from the torch, the bottom surface of the electrode being in longitudinally opposed relationship with the central exit orifice of the tip; and
opposed contact surfaces in the torch, at least one of the contact surfaces being movable relative to the other one of said contact surfaces;
the torch being operable between an idle mode in which the contact surfaces are positioned relative to each other to provide an electrically conductive path therebetween and a pilot mode in which the contact surfaces are in spaced relationship with each other whereby a pilot arc is formed between the contact surfaces;
the contact surfaces being disposed in the torch upstream from the bottom surface of the electrode whereby the pilot arc is formed generally within the primary gas flow path upstream from the bottom surface of the electrode and is blown by working gas in the primary gas flow path toward the central exit orifice of the tip for exhausting working gas from the tip in the form of an ionized plasma. - View Dependent Claims (35, 36, 37, 38, 39)
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34. A conductive element for use in a contact start plasma torch of the type having an electrode in electrical communication with the negative side of a power supply and a tip surrounding the electrode in spaced relationship therewith to at least partially define a primary gas flow path of the torch, the tip being in electrical communication with the positive side of the power supply and having a central exit orifice in fluid communication with the primary gas flow path for exhausting working gas from the tip in the form of an ionized plasma, said conductive element comprising:
a generally cup-shaped body constructed of an electrically conductive material, said conductive element being adapted for movement relative to the electrode and the tip between a first position corresponding to an idle mode of the torch in which the conductive element provides an electrically conductive path between the positive side of the power supply and the negative side of the power supply and a second position spaced from the first position of the conductive element, the second position of the conductive element corresponding to a pilot mode of the torch whereby movement of the conductive element toward its second position forms a pilot arc generally within the primary gas flow path capable of initiating operation of the torch for exhausting working gas from the torch in the form of an ionized plasma.
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40. An electrode for use in a contact start plasma torch of the type having a primary gas flow path for directing a working gas in a downstream direction through the torch, a tip surrounding the electrode in spaced relationship therewith to at least partially define the primary gas flow path of the torch, a contact surface in the torch for forming a pilot arc in the primary gas flow path of the torch and a central exit orifice in the tip communicating with the primary gas flow path for exhausting working gas from the tip in the form of an ionized plasma, the electrode comprising:
a generally cylindrical body having a longitudinally extending side surface, a bottom surface for longitudinally opposed positioning relative to the central exit to orifice of the tip, and a contact surface disposed above the bottom surface of the electrode, the contact surface of the electrode being positionable relative to said contact surface of the torch to provide an electrically conductive path therethrough for use in forming a pilot arc between the electrode contact surface and the torch contact surface generally within the primary gas flow path of the torch upstream from the bottom surface of the electrode. - View Dependent Claims (41, 42, 43, 44, 46, 47, 48, 49)
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45. A tip for use in a contact start plasma torch of the type having a primary gas flow path for directing a working gas through the torch whereby the working gas is exhausted from the torch in the form of an ionized plasma, said tip being generally cup-shaped and having a central exit opening adapted for fluid communication with the primary gas flow path for exhausting working gas from the tip in the form of an ionized plasma, the tip further having a top surface and an annular projection extending up from the top surface for use in radially positioning the tip in the torch.
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50. A tip for use in a plasma torch of the type having a primary gas flow path for directing a working gas through the torch whereby the working gas is exhausted from the torch in the form of an ionized plasma and a secondary gas flow path for directing gas through the torch whereby the gas is exhausted from the torch other than in the form of an ionized plasma, said tip being generally cup-shaped and having a central exit opening adapted for fluid communication with the primary gas flow path for exhausting working gas from the tip in the form of an ionized plasma, the tip further having at least one metering orifice adapted for fluid communication with the secondary gas flow path for metering the flow of gas through the secondary gas flow path.
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51. A contact assembly for use in a contact start plasma torch of the type having a primary gas flow path for directing a working gas through the torch, an electrode in electrical communication the negative side of a power supply and a tip surrounding the electrode in spaced relationship therewith to at least partially define the primary gas flow path of the torch, the tip being in electrical communication with the positive side of the power supply and having a central exit orifice in fluid communication with the primary gas flow path for exhausting working gas from the torch in the form of an ionized plasma, said contact assembly comprising:
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a conductive element constructed of an electrically conductive material;
an enclosure surrounding the conductive element in fluid communication with a source of pressurized gas for receiving gas into the enclosure, the conductive element being disposed at least partially within the enclosure and being movable relative to the enclosure, the electrode and the tip in response to pressurized gas received in the enclosure whereby movement of the conductive element is adapted to form a pilot arc in the torch. - View Dependent Claims (52, 53, 54, 55, 56, 59, 60, 61)
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57. An electrode assembly for use in a contact start plasma torch of the type having a cathode body adapted for electrical communication with the negative side of a power supply and an anode body adapted for electrical communication with the positive side of the power supply, the electrode assembly comprising;
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an electrode extending longitudinally within the torch and defining at least in part the cathode body of the torch; and
an insulating sleeve surrounding at least a portion of the electrode, the insulating sleeve being constructed of an electrically non-conductive material to insulate said at least a portion of the electrode against electrical communication with the anode body of the torch.
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58. A method of starting a contact start plasma torch of the type having a cathode body in electrical communication with the negative side of a power supply and an anode body in electrical communication with the positive side of the power supply, the anode body being positioned relative to the cathode body to at least partially define a primary gas flow path of the torch, the torch having a central exit orifice in fluid communication with the primary gas flow path for exhausting working gas from the torch in the form of an ionized plasma, the method comprising the acts of:
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causing an electrical current to flow along an electrically conductive path comprising the anode body, the cathode body and a conductive element electrically bridging the cathode body and the anode body in a first position of the conductive element corresponding to an idle mode of the torch;
directing working gas from a source of working gas through the primary gas flow path of the torch;
effecting movement of the conductive element relative to the cathode body and the anode body toward a second position corresponding to a pilot mode of the torch whereby a pilot arc is formed between the conductive element and at least one of said cathode body and said anode body as the conductive element is moved toward its second position; and
blowing the pilot arc through the primary gas flow path toward the central exit orifice of the torch such that working gas is exhausted from the primary gas flow path of the torch in the form of an ionized plasma.
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62. A method of starting a contact start plasma torch of the type having an electrode positioned on a longitudinal axis of the torch in electrical communication with the negative side of a power supply, the electrode having a longitudinally extending side surface and a bottom surface, and an anode body in electrical communication with the positive side of the power supply, the anode body surrounding the electrode in spaced relationship therewith to at least partially define a primary gas flow path of the torch for directing working gas through the torch, the anode body having a central exit orifice in fluid communication with the primary gas flow path for exhausting working gas from the torch, the anode being arranged relative to the electrode such that the central exit orifice is in longitudinally opposed relationship with the bottom surface of the electrode, said method comprising the acts of:
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positioning opposed contact surfaces of the torch relative to each other generally within the primary gas flow path upstream from the bottom surface of the electrode to provide an electrically conductive path through the contact surfaces;
repositioning the contact surfaces relative to each other to form a pilot arc therebetween in the primary gas flow path of the torch upstream from the bottom surface of the electrode; and
directing working gas from a source of working gas through the primary gas flow path of the torch to blow the pilot arc downstream within the primary gas flow path toward the central exit orifice of the anode body. - View Dependent Claims (63, 64)
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65. A shield cup for use in a plasma torch of the type having a primary gas flow path for directing a working gas through the torch whereby the working gas is exhausted from the torch in the form of an ionized plasma and a secondary gas flow path for directing gas through the torch whereby the gas is exhausted from the torch other than in the form of an ionized plasma, the torch having at least one metering orifice in the secondary gas flow path for metering the flow of gas through the secondary gas flow path, the shield cup being generally cup-shaped and configured for at least partially defining the secondary gas flow path, said shield cup being further configured to define a tertiary gas flow path in fluid communication with the secondary gas flow path for further exhausting gas in the secondary gas flow path from the torch, the shield cup having at least one metering orifice in said tertiary gas flow path for metering the flow of gas through the tertiary gas flow path.
Specification