| 摘要 |
PURPOSE: 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. CONSTITUTION: The plasma arc torch(10) comprises an electrode(40) including an upper tubular member(23) defining an internal bore therethrough and a metallic holder(41) having a front end and a rear end along a longitudinal axis, the front end having a front face defining a front cavity having at least an emissive element positioned therein, the rear end defining a central passageway(25) in fluid communication with the internal bore(24) for directing gas from the rear end to the front end of the holder, the holder further defining a plurality of side openings positioned proximate the front end of the holder that are in fluid communication with the central passageway; a nozzle positioned proximate the front end of the holder and defining a nozzle chamber therebetween, the nozzle defining a central bore for discharging a primary flow of gas from the nozzle chamber toward a workpiece located adjacent the nozzle; an electrical supply for creating an arc extending from the emissive element of the electrode through the central bore and to the workpiece; and a gas supply line(70) through which all gas used by the torch is supplied, the gas supply line directing all of the gas to the central passageway of the electrode, wherein all of the gas is directed to the nozzle chamber from the central passageway through the side openings defined by the holder.
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