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:
Jul. 27, 1982
Filed:
Dec. 12, 1980
Hiroyoshi Matsubara, Fukuyama, JP;
Kenji Takeshige, Fukuyama, JP;
Tatsumi Osuka, Tokyo, JP;
Takashi Nagamine, Fukuyama, JP;
Osamu Hirano, Fukuyama, JP;
Jinkichi Tanaka, Yokohama, JP;
Itaru Watanabe, Yokohama, JP;
Motoaki Suzuki, Yokohama, JP;
Nippon Kokan Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of longitudinally seam-welding steel pipes comprises the steps of providing a conductive net-like enclosure tube around a cable for supplying a direct electric current from the power source to the welding head; and conducting a direct electric current through the enclosure tube and through the steel pipe in a direction opposite to that in which the direct current runs through the cable. Apparatus for longitudinally seam-welding steel pipes comprises an electrical cable coupled to a welding head, a net tube surrounding the cable, and a device for supplying a direct electric current to the cable in a first direction and to the net enclosure tube and steel pipe in the opposite direction. The direct currents flowing in the enclosure tube and in the steel pipe is adjustably controlled to minimize the magnitude of a magnetic field created around the net enclosure tube and producing a welded steel pipe seam.