Disclosed is a plasma torch with a structure capable of performing reversed polarity/straight polarity operation, wherein the plasma torch is coupled to a melter and melts a waste material such as radioactive waste or industrial waste by generating and sustaining a plasma arc between electrodes, the plasma torch including: a rear electrode provided inside a torch pipe and electrically connected to become one of an anode and a cathode; and a front electrode provided at a front end of the torch pipe at a position adjacent to a front end of the rear electrode and electrically connected to become a remaining one of the anode and the cathode, wherein electrical connections of the rear and front electrodes are switchable with each other so that the plasma torch operates as a reversed polarity plasma torch or a straight polarity plasma torch.

A contact start liquid-cooled plasma arc cutting torch is provided that includes a translatable liquid-cooled electrode, a nozzle, and a multi-piece cathode. The electrode comprises an electrode body defining a proximal end and a distal end along a longitudinal axis of the electrode body. The electrode body includes a 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. The cathode is disposed about the proximal end of the electrode body and includes a first body shaped to matingly engage the electrode and a second body shaped to matingly engage the torch. 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.

A liquid cooled electrode for a contact start plasma arc cutting torch is provided. The electrode includes an elongated body defining a longitudinal axis. The elongated body includes a proximal end shaped to matingly engage a torch body of the plasma arc cutting torch and a distal end located substantially opposite of the proximal end along the longitudinal axis. The electrode also includes one or more contact surfaces disposed on an external surface of the distal end of the electrode body between the proximal and distal ends. The one or more contact surfaces are shaped to physically contact a nozzle disposed within the plasma arc cutting torch during a portion of a pilot arc initiation process. The physical contact is configured to support transmission of a pilot arc current between the electrode and the nozzle with a density of at least about 3000 amps per square inch.

A consumable cartridge for a plasma arc torch includes a cartridge frame having a first end and a second end opposite the first end, the first and second ends defining a longitudinal axis, the second end including a plurality of discrete retaining features. The consumable cartridge includes an electrically conductive contact element secured to the cartridge frame by the plurality of discrete retaining features and translatable up to a predetermined distance within the cartridge frame along the longitudinal axis at the second end, the contact element having a core, a proximal surface, and a distal surface. The proximal surface is shaped to contact a torch plunger of the plasma arc torch upon installation into the plasma arc torch and the distal surface is shaped to contact an electrode of the plasma arc torch during an operation of the plasma arc torch.

A plasma arc torch comprises an electrode, a tip, and a shape memory alloy (SMA) starter. The electrode and the tip that are aligned concentrically with a gap therebetween. The electrode is adapted for electrical connection to a cathodic side of a power supply and the tip is adapted for electrical connection to an anodic side of the power supply during piloting. The SMA starter comprises a SMA starter element disposed between the electrode and the tip and is configured deform when heated. A deformation of the SMA starter element draws a pilot arc that extends at least partially through the gap between the electrode and the tip.

A plasma cutting system includes a plasma cutting power supply configured to provide cutting current to a torch. A controllable gas valve regulates at least one of a flow rate and a pressure supplied to the torch. A controller is operatively connected to the power supply to control a current level, and to the gas valve to adjust a valve position. The controller is configured to receive real-time torch position information from a motion control system that controls positioning of the torch. The position information includes torch positions along a first axis and a second axis that is perpendicular to the first axis. The controller is configured to calculate respective derivatives from the torch positions along the first and second axes, and a real-time velocity magnitude of the torch from the respective derivatives, and adjust the current level and the valve position based on the calculated real-time velocity magnitude.

A plasma arc torch includes a cathode extending along an axis of the torch, a pilot arc conductor, and a nozzle body. A first fluid conduit and second fluid conduit extend parallel to the axis of the torch. A first offset fitting includes a first duct coupled to and in fluid communication with the first fluid conduit, and a second duct in fluid communication with the first duct and outwardly radially offset from the first duct and extending away from the first duct in a proximal direction. A second offset fitting includes a third duct coupled to and in fluid communication with the second fluid conduit, and a fourth duct in fluid communication with the third duct and outwardly radially offset from the third duct and extending away from the third duct in the proximal direction. A spring compression plug electrically connects the pilot arc conductor to the nozzle body.

Nozzle for a plasma torch head, laser cutting head or plasma laser cutting head, arrangement composed of such a nozzle and of a nozzle protection cap, arrangement composed of such a nozzle and of an electrode, plasma torch head, laser cutting head or plasma laser cutting head having such a nozzle and/or having such an arrangement, plasma torch comprising such a plasma torch head, laser cutting head comprising such a nozzle and/or such an arrangement, plasma laser cutting head comprising such a nozzle and/or such an arrangement, method for plasma cutting, method for laser cutting and method for plasma laser cutting using the same.

A consumable cartridge for a plasma arc torch includes a cartridge frame having a first end and a second end opposite the first end, the first and second ends defining a longitudinal axis, the second end including a plurality of discrete retaining features. The consumable cartridge includes an electrically conductive contact element secured to the cartridge frame by the plurality of discrete retaining features and translatable up to a predetermined distance within the cartridge frame along the longitudinal axis at the second end, the contact element having a core, a proximal surface, and a distal surface. The proximal surface is shaped to contact a torch plunger of the plasma arc torch upon installation into the plasma arc torch and the distal surface is shaped to contact an electrode of the plasma arc torch during an operation of the plasma arc torch.

In some aspects, methods for controlling a plasma arc in a plasma torch of a plasma cutting system in a low operating current mode can include: receiving, by a computing device within the plasma power supply, a command to begin a plasma processing operation; generating a pilot arc command to generate a pilot arc within the plasma torch, the generating of the pilot arc command including directing an electrical signal and a gas flow to the plasma torch, the electrical signal being configured to generate the pilot arc at a current having a first arc amperage magnitude; and generating an operational arc command to facilitate a transition from the pilot arc to an operational plasma arc, the generating of the operational arc command including adjusting the current directed to the plasma torch to be a second arc amperage magnitude that is lower than the first arc amperage magnitude.