A method of using a coolant tube in a liquid cooled plasma arc torch is provided. The method includes installing the coolant tube and a first electrode in the plasma arc torch. The method also includes biasing, by a first coolant flow, a biasing surface of the coolant tube against the first electrode, such that the coolant tube translates axially along the longitudinal axis to contact the first electrode. The biasing by the first coolant flow defines a first distance in an axial direction between the O-ring of the coolant tube and a proximal end of the first electrode. The method further includes removing the first electrode from the plasma arc torch and installing a second electrode in the torch. The method includes biasing, by a second coolant flow, the biasing surface of the coolant tube against the second electrode, such that the coolant tube translates axially along the longitudinal axis to contact the second electrode. The biasing by the second coolant flow defines a second distance in an axial direction between the O-ring of the coolant tube and a proximal end of the second electrode. A difference between the first distance and the second distance is at least about 0.25 inches.

A nozzle for a liquid-cooled plasma arc torch is provided. The nozzle includes a thermally conductive body having a distal end, a proximal end, and a longitudinal axis extending therethrough. The nozzle also includes a plasma arc exit orifice at the distal end of the thermally conductive body. The nozzle additionally includes a cooling waist located circumferentially about an exterior surface of the thermally conductive body. The cooling waist includes a liquid inlet slope, a liquid outlet slope and a heat exchange region between the liquid inlet slope and the liquid outlet slope. The heat exchange region extends substantially parallel to the longitudinal axis, and the liquid inlet slope and the liquid outlet slope are oriented generally perpendicular to the longitudinal axis.

A center pipe is used in a plasma torch for plasma cutting including a base portion and an electrode. The center pipe is inserted into the electrode and supplies cooling water into the electrode. The center pipe includes a pipe body and a contact piece. The pipe body is electrically connected to an electrical power source outside of the plasma torch via the base portion. The pipe body includes a cooling water channel therein. The pipe body is formed with an electrically conductive body. The contact piece is provided on the external circumferential surface of the pipe body and energizes the electrode through contact with the internal circumferential surface of the electrode. The contact piece has elasticity to produce a counterforce when pressed in the radial direction of the pipe body. The contact piece is formed with an electrically conductive body.

A replacement part unit for a plasma torch includes an electrode, an insulation guide, and a nozzle. The insulation guide includes a hole into which the electrode is inserted. The insulation guide is coupled to the electrode by press-fitting or adhesion. The nozzle includes a hole into which the insulation guide is inserted. The nozzle is coupled to the insulation guide by press-fitting or adhesion.

A resin insulation guide is used in a plasma torch including an electrode and a nozzle into which the electrode is inserted. The insulation guide is used to couple the electrode and the nozzle, and includes a first internal circumferential surface formed on an inside of the insulation guide, a second internal circumferential surface formed on the inside of the insulation guide, a communication channel, and a heat resistant coating formed on the first internal circumferential surface. The second internal circumferential surface has an inner diameter smaller than an inner diameter of the first internal circumferential surface. The communication channel communicates a space inside the first internal circumferential surface to an outside of the insulation guide, and extends in a direction inclined with respect to an axial direction of the insulation guide.

The invention relates to a cooling pipe for a plasma arc torch, comprising a hollow cylindrical electrode body having a central internal core, at the front end of which an electrode core holder having an electrode core inserted therein is arranged, and a hollow cylindrical cooling pipe which is inserted into the internal bore in a sealing manner and which features an internal bore that form a cooling channel as a feed and, in the intermediate space between the outer circumference of the internal bore and the inner circumference of the electrode body, forms a cooling channel formed as a return, wherein the cooling pipe has, on the inner side thereof that is facing the electrode core holder, space-maintaining means (e.g. a spacer washer or wires or rods), which are suitable to rest on the front end of the electrode core holder.

The present invention relates to a plasma torch including: a tube including: a first diameter part provided with a hollow channel; and a second diameter part provided at a predetermined position on the outer circumferential surface of the first diameter part; a body including: a housing part receiving the tube therein; and a plurality of first and second discharge holes formed at predetermined positions in longitudinal directions of the body; an insulator including a plurality of first discharge flow lines formed at predetermined positions vertically located from the body; an amplification tube including a space part communicating with the second discharge holes; a housing including a plurality of second discharge flow lines formed at predetermined positions of an inner circumferential surface of the housing; an inner cap combined with an outer circumferential surface of the housing; and an insulation cap engaged with an outer circumferential surface of the inner cap.

A front end assembly for a plasma torch and methods for assembling and disassembling a torch wherein a plurality of front end parts form a unit that is removable from, and installable in, the torch in a single operation without a special fixture. The front end assembly includes a nozzle retaining cup body connectable to a body of the torch, and a forward end connectable to a shield retainer. A nozzle retaining cup insert fits into the nozzle retaining cup body. The shield retainer has an inner surface for retaining the shield. A nozzle is received within the nozzle retaining cup insert. A stop on the nozzle engages the nozzle retaining cup insert when the front end assembly is removed from the torch so the nozzle does not remain in the torch. The shield engages an insulator, which engages the nozzle, to limit forward axial movement of the nozzle.

Embodiments of the present invention include a plasma cutting torch and plasma cutting torch components, such as electrodes, cathodes, retainer caps, etc. having a unique physical features, including threads relationships. Embodiments include torch components having modified square thread with a specialized thread configuration including a particular relationship between thread crest and root, and included angles of thread sidewalls.

An electrode for a consumable cartridge of a plasma arc torch is provided. The electrode comprises a substantially hollow body defining a proximal end, a distal end and a longitudinal axis extending therebetween. The electrode also includes a plurality of flanges, including a proximal flange and a distal flange, disposed circumferentially about an external surface of the hollow body and extending radially outward. Each flange defines one or more holes configured to conduct a gas flow therethrough along the external surface of the hollow body. The one or more holes on the proximal flange define a first combined cross-sectional flow area that is different from a second combined cross-sectional flow area defined by the one or more holes on the distal flange.