Abstract: A plasma arc torch includes at least one consumable component in coaxial relationship with another component of the torch. At least two compressible components are disposed between longitudinally extending coaxial surfaces of the consumable component and the second component. A pressurized medium flow path is directed to a longitudinal location between the compressible components. Upon supply of a pressurized medium through the flow path, the compressible components are caused to deform radially outward thereby centering the consumable component relative to the other component.

Abstract: A plasma arc torch includes a first consumable component having a longitudinally extending connection end. A second component in a coaxial relationship with the first consumable component has a bore defined therein into which the connection end of the first component extends. The bore includes a contact surface defined substantially perpendicular to a longitudinal axis of the torch. The connection end of the first component includes a contact shoulder defined substantially perpendicular to the longitudinal axis of the torch, a locking engagement section configured to engage with a corresponding section of the second component, and an alignment section extending longitudinally from the engagement section. The alignment section has a diameter closely matching that of the bore such so as to minimize axial misalignment between the first consumable component and the second component. The first consumable component may be an electrode.

Abstract: A plasma arc torch includes a first consumable component having a longitudinally extending connection end. A second component in a coaxial relationship with the first consumable component has a bore defined therein into which the connection end of the first component extends. The bore includes a contact surface defined substantially perpendicular to a longitudinal axis of the torch. The connection end of the first component includes a contact shoulder defined substantially perpendicular to the longitudinal axis of the torch, a locking engagement section configured to engage with a corresponding section of the second component, and an alignment section extending longitudinally from the engagement section. The alignment section has a diameter closely matching that of the bore such so as to minimize axial misalignment between the first consumable component and the second component. The first consumable component may be an electrode.

Abstract: A process for operating a plasma torch having an improved start up and shut down sequence to substantially increase electrode element life. The first shut down mode is controlled such that plasma gas flow through the swirl ring and nozzle prevents the formation of an oxide layer upon the electrode. The shut down method is especially useful for torches which operate at 100 amps or greater. The inclusion of an aluminum jacket surrounding the electrode outer walls has been found to contribute to the ability to avoid formation of oxide layers on the electrode.

Abstract: A process for operating a plasma torch having an improved start up and shut down sequence to substantially increase electrode element life. The first shut down mode is controlled such that plasma gas flow through the swirl ring and nozzle prevents the formation of an oxide layer upon the electrode. The shut down method is especially useful for torches which operate at 100 amps or greater. The inclusion of an aluminum jacket surrounding the electrode outer walls has been found to contribute to the ability to avoid formation of oxide layers on the electrode.

Abstract: A process for operating a plasma torch having an improved start up and shut down sequence to substantially increase electrode element life. The first shut down mode is controlled such that plasma gas flow through the swirl ring and nozzle prevents the formation of an oxide layer upon the electrode. The shut down method is especially useful for torches which operate at 100 amps or greater. The inclusion of an aluminum jacket surrounding the electrode outer walls has been found to contribute to the ability to avoid formation of oxide layers on the electrode.

Abstract: An apparatus and process is provided for controlling the selection and supply pressure of gases used in a plasma arc torch. A plurality of pressurized feed gases are selectively routed by solenoid gas valves to one or more motorized pressure regulators. A separate regulator controls the pressurized output of a selected pre-flow gas, plasma gas, shield gas, and post flow gas. A microprocessor establishes recommended pressures for each type of gas and prevents operating pressures from being used which may damage a plasma arc torch.

Abstract: A process for operating a plasma torch having an improved start up and shut down sequence to substantially increase electrode element life. The first shut down mode is controlled such that plasma gas flow through the swirl ring and nozzle prevents the formation of an oxide layer upon the electrode. The shut down method is especially useful for torches which operate at 100 amps or greater. The inclusion of an aluminum jacket surrounding the electrode outer walls has been found to contribute to the ability to avoid formation of oxide layers on the electrode.

Abstract: A process for operating a plasma arc torch on shut down includes decreasing current to the electrode from its initial operational value Io to a lesser intermediate value Im in a ramping function between times t1 and t2. Gas pressure within the plasma gas chamber is controlled between times t1 and t2 so that the gas pressure decreases from its operational value Po to a lesser intermediate value Pm substantially concurrently with the decreasing of current between times t1 and t2 and at a controlled rate such that plasma gas flow rate through the nozzle is maintained at least about its operational level Fo or greater between times t1 and t2. At time t2, current is shut off to the electrode.

Abstract: A process for operating a plasma torch on shut down to substantially increase electrode element life involves shutting down the plasma torch according to a first shut down mode for a first predetermined number of pierces attributed to the electrode element. The first shut down mode is controlled such that plasma gas flow through the swirl ring and nozzle decrease to zero substantially immediately upon termination of arc current to the electrode. The shut down method is switched to a second shut down mode for an additional second predetermined number of pierces. In the second shut down mode, the plasma gas flow through the swirl ring and nozzle are maintained after termination of the arc current to the electrode. The shut down mode may be switched back again to the first mode after the second predetermined number of pierces.

Abstract: A torch positioning apparatus controls a torch as it moves downward at a relatively rapid rate toward a work piece until it trips a proximity switch, causing the rate of travel of the torch to be slowed. The torch continues its travel until it strikes the work piece and stops, and the increase in the level of power required upon stopping is detected by a circuit which compares this increased power requirement with a power level previously measured and stored while the torch is moving, causing the direction of travel of the torch carriage to be reversed for a preset time so as to position the torch at the desired height above the work piece. A safety mechanism is included which shows the travel of the carriage in case the proximity switch fails.

Abstract: Disclosed herein is an electrode which may be used in plasma cutting torches which has a superior service life over similar electrodes found in the prior art, due to a design which improves cooling of the electrode, and which allows advancement and resurfacing of the electrode insert.

Abstract: A constant current welding power supply having a single transformer with a primary winding connected to a three phase input source of line voltage and two secondary windings each having a bridge rectifier for providing an open circuit starting voltage separate from the arc working voltage. Each bridge rectifier is fired by separate firing means controlled by a logic control means. One bridge rectifier is energized with an advancing firing angle proportional to a ramp output signal enabled through the control means in response to a predetermined drop in output voltage. The other bridge rectifier is energized in synchronism with the line voltage for a predetermined period of time following the predetermined drop in output voltage.