| 摘要 |
PCT No. PCT/FI87/00042 Sec. 371 Date Sep. 16, 1987 Sec. 102(e) Date Sep. 16, 1987 PCT Filed Mar. 24, 1987 PCT Pub. No. WO87/05844 PCT Pub. Date Oct. 8, 1987.The invention relates to an apparatus to be used when welding pipes together. The apparatus comprises a bellows structure (4, 5) for shielding the weld joint area by internal contact with the pipe ends on both sides of the weld joint (3). When the apparatus is inserted and, especially, pulled out after welding, the bellows tend to be damaged by the hot weld joint. It is the object of the invention to solve this problem. The object is achieved by providing both bellows (4, 5) with radial side supports (14, 15) dragging against the inner surface of the pipes and by arranging the bellows to contract within the radial side supports in the absence of an inner overpressure. Between the bellows (4, 5), centering discs (9, 10) are arranged on hoses (6, 7, 8) for leading a protective gas and compressed air. The hoses (6, 7, 8) are connected with the holders of the bellows by means of a through cotter pin provided with a spring (17) for keeping the pin stationary.
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