Abstract: A method of fabricating an electrode is disclosed, wherein the electrode comprises a copper holder defining a cavity in a forward end. An emissive element and separator assembly is positioned in the cavity. An intermetallic compound is formed between the emissive element and the separator by heating a relatively non-emissive material until it melts and dipping the emissive element therein before cooling the assembly. As a result, the intermetallic compound is formed significantly faster than by conventional methods.

Abstract: A plasma arc torch and method are provided for directing a flow of gas substantially the length of an electrode before splitting the gas into a primary flow and a secondary flow. The torch includes an electrode having a metallic holder defining a plurality of openings at a forward end for directing all of the gas therethrough and into a chamber defined by the holder and a nozzle. The nozzle defines a central bore and a plurality of secondary openings for splitting the gas in the nozzle chamber into at least the primary flow and the secondary flow.

Abstract: A plasma arc torch with improved sealing of connections between fluid passages of adjoining parts of the torch, means for reducing current leakage through a control fluid, and an improved pilot arc electrical assembly, includes a main torch body and an insulator body which abut and each of which has a plasma gas passage and a control fluid passage which extend to the abutting end faces of the bodies and are aligned thereat. Connections between the aligned plasma gas passages are made via coupling tubes each having a first portion inserted into a receiving portion of the passage in the main torch body and a second portion inserted into a receiving portion of the passage in the insulator body. Each inserted portion includes a pair of O-rings spaced apart along the length of the tube for sealing the connection.

Abstract: A plasma arc torch with improved sealing of connections between fluid passages of adjoining parts of the torch includes a main torch body and an insulator body which abut and each of which has a plasma gas passage and a control fluid passage which extend to the abutting end faces of the bodies and are aligned thereat. Connections between the aligned plasma gas passages are made via coupling tubes each having a first portion inserted into a receiving portion of the passage in the main torch body and a second portion inserted into a receiving portion of the passage in the insulator body. Each inserted portion includes a pair of O-rings spaced apart along the length of the tube for sealing the connection. An elongate insulating conduit is sealingly received within the control fluid passages of the insulator body and main torch body, and extends through the main torch body into a control fluid connector tube.

Abstract: A nozzle assembly for a plasma arc torch includes inner and outer metal nozzle members and an annular insulating element press-fit between the inner and outer nozzle members so that the nozzle members are electrically insulated from one another and bores of the nozzle members are coaxial. Additionally, the annular insulating element is constructed such that the inner and outer nozzle members are secured together to define a water passageway between the interior surface of the outer nozzle member and the exterior surface of the inner nozzle member. The nozzle assembly may further include an outer insulating element secured onto the exterior surface of the outer nozzle member, in which case the annular insulating element between the nozzle members may not be press-fit to the nozzle members. The annular insulating element may define at least one port for introducing water into the water passageway.

Abstract: A water injection plasma arc torch having a nozzle assembly positioned adjacent the discharge end of the electrode of the torch, wherein the torch is capable of operating at a current of 200 amperes or less. The nozzle assembly comprises an inner nozzle mounted adjacent an outer nozzle wherein both inner and outer nozzles have concentric bores for passage of the arc and the plasma gas flow to a workpiece. In addition, the inner nozzle is spaced from the outer nozzle to define a water passage therebetween for directing a flow of water to surround the plasma arc. A gas flow velocity of between about 40 times and about 110 times the water flow velocity provides constriction of the plasma arc, without unduly cooling the plasma arc, and produces good quality straight and bevel cuts in thin section workpieces.

Abstract: A plasma arc torch which has a cooling water passage for cooling both the electrode and the nozzle, and separate passages for a cutting gas and a shielding gas. The nozzle is centered and longitudinally held by an interengaging fit with a tubular member of the torch body, and the torch includes a heat shield assembly which retains and supports the nozzle of the torch on the tubular member. The heat shield assembly also defines a portion of the cooling water passage as well as a portion of the shielding gas passage, and it may be unthreaded and removed from the torch as a unit. When so removed, the water passage is opened which acts to disconnect the power to the torch.