Pipe stopper method and apparatus

摘要

A hollow tubular body is welded to a distribution pipeline in surrounding relation with a cut-out portion of the pipeline. A plug assembly is inserted through an opened gate valve attached to the tubular body and into engagement with the tubular body. The gate valve is removed and an operator device is attached to the plug assembly. The plug assembly includes an expandable portion and an insert portion. The expandable portion includes an enlarged first chamber and a reduced second chamber. A plug assembly guide is positioned between the expandable portion and the insert portion. A nonrising actuating stem is rotated to nonrotatably move the plug assembly guide to advance the expandable portion through the tubular body and the cut-out portion to a position abutting the bottom of the pipeline for expansion of the expandable portion. Continued rotation of the stem downwardly advances the plug assembly guide to exert a first force externally and downwardly upon the expandable portion and move the insert portion into the expandable portion reduced second chamber to exert a second force internally and radially outwardly upon the expandable portion. Thus the expandable portion is expanded outwardly into sealing relation with the pipeline to block flow in the pipeline.