Underground pipe replacement method and apparatus

Abstract

Underground frangible pipe replacement apparatus and methods for replacing an existing unserviceable pipe by first crushing the existing pipe entirely inwardly, or imploding it, to destroy it. The resulting shards are then forced outwardly into the surrounding soil, creating a bore large enough to accommodate a replacement pipe at least as large as, or large than, the old pipe. The new pipe is pulled into place substantially simultaneously with the expansion of the bore. The crushing tool includes a generally tubular main body and a plurality of longitudinally extending, tapered blades circumferentially disposed about the ID of the main body of the crushing tool. The blades taper outwardly and forwardly from near the midportion of the crushing tool. The crushing tool has a connecting rod at its center, including means for connecting the crushing tool to a motive force at one end and means for connecting the crushing tool to the expanding plug at the other end. A plurality of bell-engaging knuckles are disposed around the ID of the main body of the crushing tool between the blades. The rear end of the crushing tool is tapered inwardly and rearwardly. The expanding plug connects to the trailing end of the crushing tool, and includes a conical nose for expanding the crushed pipe fragments into the surrounding soil. The plug is pulled through the ground behind and along with the crushing tool, pulling with it the new pipe.

Dependencies are inferred from the claim text.