Method and device for plugging a gas main

A method of sealing a pipe, comprising the steps of:

• a. coupling a fitting to the pipe;
• b. cutting a coupon out of the pipe at the fitting;
• c. engaging a stopper through the fitting into a position lodged in the pipe;
• d. cutting the pipe leaving a pipe stub coupled to the fitting;
• e. inserting into the pipe stub an expandable plug comprising a pair of plates configured for insertion into the pipe, a sealing member disposed between the plates, means for squeezing the plates together to compress the sealing member, and stabilizing means for stabilizing the plug within the pipe as the plates are squeezed together, whereby as the plates are squeezed together the sealing member expands in a radial direction such that a periphery of the sealing member engages an interior wall of the pipe;
• f. providing a vent hole for the venting of heated air from a portion of the pipe stub between the expandable plug and an open end of the pipe stub, and
• g. welding a permanent cap over an open end of the pipe stub.

A method of bypassing a pipe section, comprising the steps of:

• a. coupling a tee fitting to each end of the pipe section;
• b. coupling a bypass pipe to each tee fitting;
• c. cutting a coupon out of the pipe section at each tee fitting;
• d. engaging a stopper through the tee fitting into a position lodged in the pipe section;
• e. cutting the pipe section leaving a pipe stub coupled to each tee fitting;
• f. inserting into each pipe stub an expandable plug comprising a pair of plates configured for insertion into the pipe, a sealing member disposed between the plates, means for squeezing the plates together to compress the sealing member, and stabilizing means for stabilizing the plug within the pipe as the plates are squeezed together, whereby as the plates are squeezed together the sealing member expands in a radial direction such that a periphery of the sealing member engages an interior wall of the pipe;
• g. providing a vent hole for the venting of heated air from a portion of the pipe stub between the expandable plug and an open end of the pipe stub, and
• h. welding a permanent cap over the open end of each pipe stub.

An expandable plug for sealing a pipe, comprising

• a pair of plates configured for insertion into the pipe,
• a sealing member disposed between the plates,
• bolts engaging the plates and having a thread with a first pitch to which nuts are engaged for squeezing the plates together to compress the sealing member, and
• stabilizing means for stabilizing the plug within the pipe as the plates are squeezed together, comprising a threaded portion having a thread with a second pitch directed opposite to the first pitch,
• whereby as the plates are squeezed together by tightening the nuts the sealing member expands in a radial direction such that a periphery of the sealing member engages an interior wall of the pipe and a tool engaging the stabilizing means stabilizes the plug during tightening.