Abstract: A plasma-arc torch system is disclosed wherein a source provides gas and electrical power. A delivery device is connected to the source for supplying the gas and electrical power to a plasma-arc torch. A filter is disposed within the delivery device for filtering the gas being supplied to the plasma-arc torch. The filter provides more uniform operation and improved gas mixing.

Abstract: A unique torch assembly having specific characteristics determinative of the desired operating parameters of the torch assembly wherein the torch assembly has a connector plug for selectively connecting the torch assembly onto a universal control station for providing electrical power and gas to said torch assembly, which power and gas flow are to match said operating parameters of the torch assembly. The assembly is provided with an identification circuit for identifying unique torch assemblies with the identification circuit having an electrical property unique to said specific characteristics of unique torch assembly and is also provided with an arrangement to interrogate the identification circuit to sense said electrical property of the circuit. In this manner, the torch assembly can be positively identified.

Abstract: A plasma torch having an electrode with an insert disposed in an insert bore at one end and includes a vent to prevent high pressure cutting oil vapor generated by evaporation of cutting oil trapped in the cavity between the insert and the insert bore. The vent is a groove formed between the cavity and the outer surface of the electrode from pushing the insert out of the insert bore.

Abstract: A plasma arc torch system includes a fault detect circuit for sensing a short between the electrode and the nozzle and disabling the power supply when the short is sensed. A sensing circuit within the torch cable is provided for actuating the fault detect circuit when the cable is severely punctured. The sensing circuit includes a foil embedded within the cable which circumscribes the main conductor to which a drain lead is connected. The drain lead senses a short between the foil and main conductor from a penetrating foreign object and actuates the fault detect circuit. Additionally, the fault detect circuit is effective in combination with a unique continuity interlock circuit disclosed to insure a safe torch. Further, a rectified control circuit is provided to maintain a stable arc preventing erosion of the nozzle and subsequent exposure of the electrode.