Pipe replacement method and rotary impact mechanism for pipe bursting

摘要

An impactor for use with a directional boring machine having a drill string connectable to the impactor for pulling the impactor through an existing pipeline uses rotation of the drill string to drive an internal striker. The internal striker delivers impacts in the pulling direction to an impactor housing as the impactor housing tows a replacement pipe behind it. The impactor housing is free to move axially in response to impacts from the striker over a limited distance in the pulling direction independently of the replacement pipe and drill string.