Propulsion pipe laying system

Abstract

A propulsion-jack driven pipe laying system including a pilot head having a cutter mounted at the leading end thereof and a propulsion-jack mounted in a pit behind the pilot head for propelling the same into the underground. The system further includes a water supply pipe and a slurry discharge pipe both mounted to the pilot head. Earth and sand excavated by the cutter is introduced into a receiving chamber where it is mixed with water supplied through the water pipe and converted into a slurry and the slurry is discharged through the slurry discharge pipe. In one embodiment, a flowmeter is disposed in a slurry conduit connected with the slurry discharge pipe for detecting flow rate of the slurry and controlling the restriction rate of a valve disposed in the slurry conduit. In another embodiment, a differential pressure detector is mounted within underground pressure at the cutter and a pressure in the receiving chamber and controlling the restriction rate of a valve disposed in the slurry circuit.