HYDRAULIC CONTROL ARRANGEMENT FOR A PIPE RELINING MACHINE

摘要

An hydraulic control arrangement ( 66 ) in association with a pipe relining machine Includes fluid pressure supply and return lines ( 32, 33 ), a motor controller ( 80 ) to control a motor ( 67 ) and a radial position controller. The radial position controller supplies fluid under pressure to a radial positioning arrangement ( 46 ) to set diameter of a relined pipe. The radial position controller has a first normally closed valve ( 83 ) supplying fluid under pressure to the radial positioning arrangement ( 46 ) and a second normally open valve ( 84 ) allowing fluid to be withdrawn from the radial positioning arrangement ( 46 ). The arrangement ( 66 ) allows the pipe relining machine to be withdrawn in the event of a failure.