Hitachi, Ltd.

Tokyo Gas Company Limited

Yasuzi Sakuma

Seishi Watahiki

Shinichi Kurita

Masayoshi Yamaguchi

Takashi Yamade

Kiyoshi Sakamoto

Atsushi Takagi

Chikara Sato

Norihiko Ozaki

Shinji Sonoda

A plasma welding method has successive steps including pre-heating of members to be welded, tack welding of the members for tentatively fixing these members, keyhole welding for completely welding the members to each other, and finish padding. These steps are automatically conducted by a single plasma welding apparatus operative in accordance with a programmed sequence including data concerning the optimum conditions of operation in each step in relation to the conditions such as sizes and materials of the members to be welded. The apparatus has a welding torch, a welding head on which the welding torch is mounted for rotation, a controller adapted for storing the optimum welding conditions for successive steps of the welding process in relation to the conditions of the members to be welded, a power supply system for transmitting welding current and welding speed signal to the welding head in accordance with a command provided by the controller, and a gas supply system for supplying a plasma gas at a rate determined in accordance with a command from the controller.

Method of and apparatus for conducting plasma welding

Method of and apparatus for automatically conducting all position plasma

A piping travelling apparatus having a plurality of continuous treads driven by motors through transmission gearing. The continuous treads are mounted to a frame and spaced apart a predetermined distance peripherally of the inner wall surface of the piping. At least one of the continuous treads is kept in contact with the inner wall surface of the piping no matter what the posture of the apparatus may be, so that the apparatus can travel without any trouble even if its posture undergoes a change when it moves along elevations and depressions on the inner wall surface of the piping or negotiates the boundary between different levels of the inner wall surface or bends of the piping. The apparatus enables a travel through piping of relatively small diameter having vertical or steeply slanted pipes to be made without any trouble.

Piping travelling apparatus

A moving apparatus for moving a moving member within a hollow curved pipe arrangement and method of performing operations within the pipe arrangement by using the apparatus, with the apparatus including a long moving member made of a material having an elasticity and a moderate degree of flexibility, a supporting device for continuously winding the moving member therearound and for supporting the same, and a prime mover connected to the supporting device, through a rotating shaft, so as to supply an electric power to the supporting device at the time of winding the moving member, whereby an elastic strain energy is stored in the moving member by rotating the supporting device by the prime mover and winding the moving member around the same, and, while the elastic strain energy thus stored is continuously released, the moving member is allowed continuously to move within the pipe arrangement. The operations performed include drawing a wire into the pipe arrangement, and inspecting the interior of the pipe arrangement by providing an inspection device on a tip end of the moving member of the moving apparatus and performing continuous inspecting operations within the pipe arrangement while the moving member is moved within the pipe arrangement.

Moving apparatus for a hollow curved pipe-arrangement and an operating

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Hitachi, Japan

Yasuzi Sakuma