Sealing construction for gas mains and the like

Claim 1

A sacrificial seal adapted to be inserted within a portion of a pressure-containing gas main and the like comprising an externally threaded member adapted to be received within a companion threaded opening within a portion of the gas main, said threaded member having an external recess and an axially aligned threaded opening, a rigid inflexIble stem including a threaded portion received in said threaded opening of said member and extending outwardly in said recess, said threaded portion of said stem configurated to engageably receive a tool for effecting movement of said stem within said recess of said member, elongated spacer means to determine the depth at which the seal is to be effected and operatively bearing at one end thereof against said threaded member, a resilient expandable seal bearing at one end against said spacer means, means forming an abutment at the end of said stem and adapted to bear against said sealing member which is compressed against the complementary end of said spacer member, said resilient means being proportioned to fit within said main while the main is under pressure, said stem being movable to effect compression of said seal against the end of said spacer means to form a seal within the main while the main is under pressure to produce a seal which is mechanically held in place through said spacer means and said threaded member and is permanently joinable to said main.