Nippon Steel Corporation

Electro Plasma, Inc.

Tsuyoshi Shinoda

Erich Muehlberger

Albert Sickinger

Koichi Takeda

Stephan E Meuhlberger

Nobuyoshi Hirotsu

Don E Bailey

Hiroshi Shiraishi

Nobuo Tajima

Masamichi Koga

A supersonic plasma system in which a vacuum source creates a low static pressure environment within an enclosure containing a plasma gun and a workpiece has plural cathodes of sealed, modular construction in conjunction with a common anode, to provide higher levels of operating power and other advantages which flow from a segmented cathode gun configuration. Inert gas independently introduced into the plural cathodes undergoes swirling motion over the cathode tips. The anode is of modular construction for easy replacement in order to change the configuration of a nozzle, a plurality of arc chambers receiving the plural cathodes or a central mixing chamber between the nozzle and the arc chambers within the anode and coupled to a central powder feed. The powder feed includes a replaceable insert which includes at least one and preferably a plurality of powder feed ports into the various arc chambers. Alternatively, metal which has already been heated to a molten state can be fed directly into the central mixing chamber. The modular cathodes which are independently powered by separate D.C. power sources are also independently cooled by separate cooling water systems as is the common anode. The cooling systems are configured to produce swirling of the cooling water so that cooling action is maximized.

Modular segmented cathode plasma generator

A transfer-type plasma torch may be used to heat objects, for example, to heat molten steel at a certain stage of being supplied from a converter to a continuous casting mold. After a trigger electric discharge has been produced between the cathode and the ignition anode of the plasma torch, an electric discharge is effected between the cathode and an object to be treated that is set as the anode. The plasma torch includes a cylindrical cathode-holding member having therein a space allowing for the flow of coolant, an ignition anode disposed within the cathode-holding member, and a ring-shaped cathode disposed on an inner periphery of the cathode-holding member and positioned below the tip of the ignition anode, with the tip portion of the cathode projecting downwardly from the bottom face of the cathode-holding member. This arrangement eliminates a conventional nozzle, thereby allowing for a reduction in a diameter of the entire torch while enabling a relative increase in the diameter of the cathode. Thus, the plasma torch exhibits a large capacity for arc current.

Transfer-type plasma torch with ring-shaped cathode and with processing

Growing community of inventors

Kitakyushu, Japan

Tsuyoshi Shinoda