MECHANICAL PLUG FOR WORK OF BORING GAS PIPING AND WORK METHOD FOR GAS PIPING FOR FIXING WELDED CUP BY USING THE PLUG

摘要

PROBLEM TO BE SOLVED: To provide a mechanical plug that helps to reduce the excavated ground area for working grooves in work of gas piping for fixing welded cups for lowered earthwork costs, and requires not two but only one gasbag insertion hole formed to shut gas away therein. ;SOLUTION: A plug body 1 is formed out of an external thread 2 at its lower portion adapted to mesh with an internal thread cut in a gasbag insertion hole formed through an existing gas pipeline, with a vertically V-sectioned, tapered sealing surface 4 used for the weld to a primary plug inside its vertical through hole, and with an internal thread 5 above the sealing surface 4. Into the plug body 1 are detachably fitted, a primary plug 6 formed with a vertically V-sectioned, tapered sealing surface 7 adapted to closely fit to the sealing surface 4, a secondary plug 11 formed with an external thread 12 adapted to mesh with the internal thread 5 of the plug body 1, and a sealing member 14 interposed between the primary and the secondary plugs 6 and 11.;COPYRIGHT: (C)1998,JPO