Plug, for fluid-sealing of tubes

Abstract

In an embodiment shown, the plug comprises a body having a central, threaded bore in which is received the threaded shank of a nosepiece. Jaws are slidably engaged with a ramp surface of the nosepiece for effecting a gripping engagement with the inner surface of a tube to be sealed. The body has an abutment formed thereon against which to receive a compression washer and a plurality or O-ring seals interleaved with other compression washers. The shank of the nosepiece is threadedly movable extensibly from and retractably toward the body by use of a wrench engageable with a hexagonal recess formed in the body-engaging end of the shank. As the nosepiece is retracted, the jaws slide along, and expand upon, the ramp surface. The O-ring seals and compression washers set against the abutment of the body, as noted, and an internally-threaded nut is threadedly engaged with an externally-threaded end of the body which is opposite the nosepiece. Threaded movement of the nut causes the O-ring seals to be compressed and expand into sealing engagement with the inner surface of a tube. With failure of one or more of the O-ring seals, the nut, body and O-ring seals, with their compression washers, can be removed from the tube in which the plug is grippingly engaged, while the nosepiece and jaws remain gripped therein. Then, upon failed O-ring seals being replaced on the body, the latter, with the replacement seals and washers can be returned to the tube and threadedly re-engaged with the nosepiece.