| 摘要 |
A T-joint fitting of the type having a two-part housing adapted to be clamped to a transport pipe is provided with a piston, which is axially displaceable within the housing for piercing a hole in the wall of the transport pipe. When the pipe is made of copper or similar soft material the axial movement is caused by a nut used for closing the passage in which the piston operates, the nut further being provided with an internally threaded bore, mating with a rearwardly extending, threaded bar on the piston. The threads on the bar and on the externally threaded portion of the housing, with which the nut cooperates, have the same pitch, but are oppositely handed, so that screwing on of the nut will simultaneously force the piston inwards. The two parts of the housing are clamped together by four bolts, and a packing of elastomeric material covers the part of the transport pipe to be pierced by the piston and has a waffle-textured face to turn towards the pipe.
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