A method for piercing and cutting a workpiece that includes the use of a plasma torch having an electrode and a nozzle spaced from and surrounding a distal end portion of the electrode to form a process gas flow channel. According to one implementation the method includes delivering a plasma gas at a first pressure through the process gas flow channel of the torch while ionizing the plasma gas to produce a plasma arc that extends between the electrode and the workpiece. While the plasma gas is delivered at the first pressure, performing a piercing operation by producing a pierce hole in the workpiece using the plasma arc. Subsequent to the piercing operation, performing a cutting operation by delivering through the process gas flow channel the plasma gas at a second pressure lower than the first pressure, and with the plasma gas being delivered at the second pressure, forming a cut in the workpiece that originates at and extends away from a boundary of the pierce hole.

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.

Atmospheric-pressure plasma generation device 10 of the present invention includes heat sinks 27 and 28. Flow paths are formed in the heat sinks, and cooling gas flows in the flow paths, thereby cooling lower housing 20 in which a reaction chamber is formed. Here, the gas used for cooling is warmed by the heat of the lower housing. The warmed gas is supplied into heated gas supply device 14 and heated by heater 112. The heated gas flows in lower cover 22 and is emitted together with plasma gas from lower cover 22 toward a processing object. Consequently, it is possible to perform cooling of the lower housing heated by electric discharge and perform heating of the processing object, and it is possible to reduce energy required for heating gas.

A plasma generation device includes a plasma head configured to eject plasma gas that is plasmatized, a gas supply device configured to supply gas serving as the plasma gas to the plasma head, a pair of electrodes that is provided in the plasma head, the pair of electrodes being configured to perform discharging for a part of the gas supplied from the gas supply device to generate the plasma gas, a temperature sensor that is provided in the plasma head, the temperature sensor being configured to measure a temperature of the plasma head; and a control device, in which the control device executes a cooling process of cooling the plasma head by causing the gas supply device to continue supply of the gas until the temperature sensor measures a temperature equal to or less than a predetermined value after the discharging of the pair of electrodes is stopped.

A method for coating a surface with a coating jet containing coating particles includes forming the coating jet from at least two partial jets. The method also includes forming one of the exit channels as a spray channel for a first gas stream containing the coating particles. The method also includes forming the other of the exit channels as a control channel. In case of a deviation of the ascertained spray angle (α) from the predetermined target spray angle, the method also includes increasing the volume flow of a first partial jet of the at least two partial jets, and decreasing the volume flow of a second partial jet of the at least two partial jets.

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.

The invention features a replaceable cartridge for a plasma arc torch. The cartridge includes a cartridge body having a first section and a second section. The first and second sections are joined at an interface to form a substantially hollow chamber. The interface provides a coupling force that secures the first and second sections together. The cartridge also includes an arc constricting member located in the second section; an electrode included within the substantially hollow chamber; and a contact start spring element affixed to the electrode. The spring element imparts a separating force that biases the electrode toward at least one of the first section or the second section of the body. The separating force has a magnitude that is less than a magnitude of the coupling force.

It is an object of the present invention to provide a plasma generator capable of efficiently identifying the cause of an abnormal stoppage when an abnormal stoppage of the plasma generator occurs. When the controller determines that at least one detected value has become an abnormal value, the controller terminates plasma generation control. Further, in response to starting plasma generation control, the controller causes the storage section to store a history of detected values in association with time. As a result, it is possible to provide a history of detected values stored in the storage section to efficiently identify the cause of the abnormal stoppage.

A system for plasma ignition and maintenance of an atmospheric pressure plasma. The system has a variable frequency alternating current (AC) power source, a transformer, a cable connected to a secondary winding of the transformer, a programmed microprocessor for control of power to the atmospheric pressure plasma. The microprocessor is configured to a) at pre-ignition, power the AC power source at an operational frequency f.sub.op higher than the resonant frequency f.sub.r, b) decrease the operational frequency f.sub.op of the AC power source until there is plasma ignition, and c) after the plasma ignition, further decrease the operational frequency f.sub.op of the AC power source to a frequency lower than the resonant frequency f.sub.r.