Process for removing the core of earth from a pipe laid without excavation and scraper for implementing said process

摘要

PCT No. PCT/DE95/00159 Sec. 371 Date Aug. 14, 1996 Sec. 102(e) Date Aug. 14, 1996 PCT Filed Feb. 9, 1995 PCT Pub. No. WO95/21984 PCT Pub. Date Aug. 17, 1995A go-devil (1) is inserted into a pipe end of a pipe (5) laid in place in trenchless manner by ramming or pressing and of which the earth core (7) shall be removed by a method of the invention, said go-devil being displaced longitudinally through said pipe and forcing the said earth core out at the other pipe end. The advance of the go-devil (1) takes place step by step by means of a length-variable actuator (10) bracing itself against the inside wall (4) of the pipe (5), said actuator after each forward stroke being returned into its initial position and its bracing being made to follow in the direction of advance by the amount of the step taken. The go-devil (1) is composed of a head plate (2), a length-variable actuator (10) and bracing systems (11, 22), the head plate (2) being linked to one end of the actuator (10) and to a first bracing system (11) and the other end of the actuator (10) being linked to a second bracing system (22), these bracing systems (11, 22) being alternatively displaceable into one bracing position wherein they can be forced against the inside wall (4) of a pipe or into a disengaged position wherein they are off the inside wall (4) of the pipe.