A nozzle of a plasma arc torch is provided. The nozzle is configured to reduce fluid pressure surging in a nozzle plenum. The nozzle comprises a nozzle body having a proximal end and a distal end. The nozzle plenum is defined between the nozzle body and an electrode of the plasma arc torch. The nozzle includes a nozzle plenum gas inlet located at the proximal end of the nozzle body, a plasma gas exit orifice located at the distal end of the nozzle body, a plasma gas passageway fluidly connecting the nozzle plenum gas inlet to the plasma gas exit orifice, and an isolation chamber fluidly connected to the plasma gas passageway and the nozzle plenum. The isolation chamber is sized to receive a volume of substantially stagnant gas to reduce the fluid pressure surging in the nozzle plenum.

A plasma gas swirl ring for a liquid cooled plasma arc torch is provided. The swirl ring comprises a substantially hollow body having a distal end, a proximal end, an interior region defined by an interior surface, and an exterior surface. The interior region of the body is configured to receive an electrode of the plasma arc torch. The swirl ring comprises a first opening disposed within a portion of the proximal end of the body, a second opening disposed about a central portion of the body, and a third opening comprising at least one swirling port disposed within a portion of the distal end of the body. The third opening is configured to provide a swirling flow of the plasma gas about the electrode at the distal end of the body.

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.

The present invention provides a glow discharge assembly that includes an electrically conductive cylindrical screen, a flange assembly, an electrode, an insulator and a non-conductive granular material. The electrically conductive cylindrical screen has an open end and a closed end. The flange assembly is attached to and electrically connected to the open end of the electrically conductive cylindrical screen. The flange assembly has a hole with a first diameter aligned with a longitudinal axis of the electrically conductive cylindrical screen. The electrode is aligned with the longitudinal axis of the electrically conductive cylindrical screen and extends through the hole of the flange assembly into the electrically conductive cylindrical screen. The insulator seals the hole of the flange assembly around the electrode and maintains a substantially equidistant gap between the electrically conductive cylindrical screen and the electrode. The non-conductive granular material is disposed within the substantially equidistant gap.

A consumable set is provided that is usable in a plasma arc torch to direct a plasma arc to a processing surface of a workpiece. The consumable set comprises a nozzle and an alignment surface. The nozzle includes: 1) a nozzle body defining a longitudinal axis extending therethrough, and 2) a nozzle exit orifice disposed in the nozzle body for constricting the plasma arc. The nozzle exit orifice defines an exit orifice axis oriented at a non-zero bevel angle relative to the longitudinal axis. The alignment surface is generally parallel to the exit orifice axis and dimensioned to align the exit orifice such that the plasma arc impinges orthogonally on the processing surface of the workpiece. The alignment surface is configured to lay at least substantially flush against a guiding surface angled relative to the processing surface of the workpiece.

Certain embodiments described herein are directed to induction devices that can be used to sustain a plasma. In certain configurations, the induction device may comprise one or more radial fins electrically coupled to a base. The induction device may take numerous forms including, for example, coils and plate electrodes.

In some aspects, torch receptacles for coupling a plasma arc torch to a torch lead can include: a body having a first end to connect to the torch lead and a second end to connect to a torch body; a set of ports within the first end to fluidly connect to a set of fluid conduits within the torch lead; and a multiway valve within the body and fluidly connected to the set of ports and to a torch gas conduit formed in the second end, the multiway valve being configured to: i) manipulate a flow of fluids between the first end and the second end to select from primary gases entering the set of ports, ii) deliver a selected primary gas to the torch body through the torch gas conduit, and iii) fluidly connect the torch gas conduit to a gas supply manifold of the plasma cutting system.

Gas flow control for a plasma arc torch is provided. More particularly, a method and apparatus to modulate the pressure and flow from a plasma arc torch is provided. Cyclic pulsing of a flow control valve between states of fully open and fully closed provides for a relatively constant flow of plasma gas to the torch at a relatively constant pressure.

A consumable set is provided that is usable in a plasma arc torch to direct a plasma arc to a processing surface of a workpiece. The consumable set comprises a nozzle and an alignment surface. The nozzle includes: 1) a nozzle body defining a longitudinal axis extending therethrough, and 2) a nozzle exit orifice disposed in the nozzle body for constricting the plasma arc. The nozzle exit orifice defines an exit orifice axis oriented at a non-zero bevel angle relative to the longitudinal axis. The alignment surface is generally parallel to the exit orifice axis and dimensioned to align the exit orifice such that the plasma arc impinges orthogonally on the processing surface of the workpiece. The alignment surface is configured to lay at least substantially flush against a guiding surface angled relative to the processing surface of the workpiece.