SPEED CONTROL DRIVE SESCTION WITH FAILSAFE VALVE

摘要

A system and method for retrieving a pipeline tool from a pipeline includes a speed control drive section that includes a primary bypass flow valve and a failsafe valve located in a central bypass flow passageway of the drive section. The failsafe valve is placed under the control of a controller. The controller is programmed to release the failsafe valve under prescribed failure conditions. An actuating means moves the failsafe valve between a normally opened positioned and a closed position in response to the controller.