The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 18, 1990
Filed:
Apr. 19, 1989
Hiroshi Shiraishi, Kitakyushu, JP;
Nobuo Tajima, Kitakyushu, JP;
Tsuyoshi Shinoda, Kitakyushu, JP;
Nobuyoshi Hirotsu, Kitakyushu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
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.