Method of and device for plasma arc welding

Claim 3

A method according to claim 1 wherein the electrode is tubular, and comprising the further step of electrically insulating said nozzle internally.

Claim 4

A method according to claim 1 further comprising placing at least the terminal part of the electrode outside the center line of the plasma aperture of the nozzle, establishing said plasma arc from said terminal part through said aperture to the workpiece, and feeding the filler wire axially into the plasma arc through the center of the plasma aperture.

Claim 5

A method according to claim 1 wherein an electrically conductive filler wire is used, comprising the further step of establishing a voltage potential between filler wire and workpiece.

Claim 6

A method according to claim 4 wherein said electrode through which the filler wire is fed is tubular.

Claim 7

A method according to claim 4 further comprising placing at least the terminal part of the electrode outside the centerline of the plasma aperture of the nozzle and establishing said arc from said terminal part through said aperture to the workpiece.

Claim 8

In a device for performing plasma arc welding on a workpiece, using a filler wire a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within said nozzle, the electrode having an axial bore and being placed on the center line of the plasma aperture of the nozzle, an electrically insulating lining disposed in said bore, and means for feeding filler wire through this bore and through the center of the plasma aperture of the nozzle, and means for maintaining the plasma arc between the electrode and the workpiece.

Claim 9

In a device for performing plasma arc welding on a workpiece, using a filler wire a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within said nozzle, the electrode having an axial bore and being placed on the center line of the plasma aperture of the nozzle, an electrically insulating lining disposed in said bore, and means for feeding filler wire through this bore and through the center of the plasma aperture of the nozzle, and means for maintaining the plasma arc between the electrode and the workpiece.

Claim 10

In a device for performing plasma arc welding with a filler wire on a workpiece, a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within the nozzle with at least the terminal part of the electrode outside the centerline of the nozzle aperture, the electrode having an axial bore, means for establishing the plasma arc from said terminal part through the aperture to the workpiece and means for feeding the filler wire axially into the arc through the center of said aperture.

Claim 11

In a device for performing plasma arc welding with a filler wire on a workpiece, a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within the nozzle with at least the terminal part of the electrode outside the centerline of the nozzle aperture, the electrode having an axial bore, means for establishing the plasma arc from said terminal part through the aperture to the workpiece and means for feeding the filler wire axially into the arc through the center of said aperture.

Claim 12

In a device for performing plasma arc welding with an electrically conductive filler wire on a workpiece, a nozzle with an aperture for constricting the plasma arc, a nonconsumable, tubular electrode within the nozzle with at least the terminal part of the electrode outside the centerline of the nozzle aperture, the electrode having an axial bore, means for establishing the plasma arc from said terminal part though the aperture to the workpiece, means for feeding the filler wire axially into arc through the center of said aperture, and means for establishing a voltage potential between the filler wire and the workpiece.

Claim 13

In a device for performing plasma arc welding with an electrically conductive filler wire on a workpiece, a nozzle with an aperture for constricting the plasma arc, a nonconsumable, tubular electrode within the nozzle with at least the terminal part of the electrode outside the centerline of the nozzle aperture, the electrode having an axial bore, means for establishing the plasma arc from said terminal part though the aperture to the workpiece, means for feeding the filler wire axially into arc through the center of said aperture, and means for establishing a voltage potential between the filler wire and the workpiece.

Claim 14

In a device for performing plasma arc welding with a filler wire on a workpiece a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within said nozzle, the electrode having a bore through which the filler wire is axially feedable, means for feeding said filler wire through said bore, means for introducing plasma gas into the nozzle, and circuit means for establishing a pLasma arc from the electrode through the aperture to the workpiece.

Claim 15

In a device for performing plasma arc welding with a filler wire on a workpiece a nozzle with an aperture for constricting the plasma arc, a nonconsumable tubular electrode within said nozzle, the electrode having a bore through which the filler wire is axially feedable, means for feeding said filler wire through said bore, means for introducing plasma gas into the nozzle, and circuit means for establishing a pLasma arc from the electrode through the aperture to the workpiece.

Claim 16

A device according to claim 10 further comprising means for adjusting the distance between the electrode and the plasma aperture in the nozzle.

Claim 17

A device according to claim 10 wherein the electrode comprises a portion made of high heat conducting metal and an end part of high melting point metal to be subjected to the filler wire.

Claim 18

A device according to claim 12 wherein the high melting point part of the electrode is annular.

Claim 19

A device according to claim 12 wherein the high melting point part of the electrode is pin shaped.

Claim 20

A device according to claim 10 wherein the nozzle comprises a detachable nipple in which plasma aperture is located

Claim 21

In a plasma arc welding apparatus for use with filler wire, plasma and protective gas supply and a workpiece, a tubular nozzle having a bore which defines an aperture at one end and a fluid duct within the nozzle walls for cooling same, a non-consumable tubular electrode having a bore and disposed within the bore of the nozzle with a first end of the electrode generally adjacent said nozzle aperture and a passageway for plasma gas defined between the electrode and bore walls of the nozzle, an electrically insulating lining within the bore of said electrode, a housing disposed about the nozzle and defining therewith a passage for protective gas flow adjacent the nozzle aperture, and means for establishing an electrical potential between said electrode and a workpiece, whereby a plasma arc is establishable through the aperture between said first end of the electrode and the workpiece, the filler wire being feedable axially through bore of the liner in the electrode into the plasma are for deposition on the workpiece.

Claim 22

In a plasma arc welding apparatus for use with filler wire, plasma and protective gas supply and a workpiece, a tubular nozzle having a bore which defines an aperture at one end and a fluid duct within the nozzle walls for cooling same, a non-consumable tubular electrode having a bore and disposed within the bore of the nozzle with a first end of the electrode generally adjacent said nozzle aperture and a passageway for plasma gas defined between the electrode and bore walls of the nozzle, an electrically insulating lining within the bore of said electrode, a housing disposed about the nozzle and defining therewith a passage for protective gas flow adjacent the nozzle aperture, and means for establishing an electrical potential between said electrode and a workpiece, whereby a plasma arc is establishable through the aperture between said first end of the electrode and the workpiece, the filler wire being feedable axially through bore of the liner in the electrode into the plasma are for deposition on the workpiece.

Claim 23

An apparatus according to claim 16 wherein said aperture has a diameter of about 7 mm. and a height of about 5 mm.