Patent ID: 7188681

Claim:
A tool for moving within a borehole, comprising: an elongate body adapted to be connected to a fluid conduit so that an internal flow chamber of the body is in fluid communication with the conduit; at least one fluid-actuated gripper assembly slidably coupled to the body for selectively gripping an inner surface of the borehole; at least one propulsion assembly for propelling the body through the borehole when the gripper assembly is gripping the inner surface of the borehole; and a valve system comprising: tool movement control valves configured to direct pressurized fluid from the internal flow chamber of the body to the gripper assembly and the propulsion assembly to propel the body within the borehole; a hydraulically controlled inlet valve having an open position in which the hydraulically controlled inlet valve provides a flow path for a flow of fluid from the internal flow chamber of the body to the movement control valves, and a closed position in which the hydraulically controlled inlet valve prevents flow of fluid from the internal flow chamber of the body to the movement control valves; and an electrically controlled valve having an open position in which the electrically controlled valve provides a flow path from the internal flow chamber of the body to the hydraulically controlled inlet valve, and a closed position in which the electrically controlled valve prevents flow of fluid from the internal flow chamber of the body through the electrically controlled valve to the hydraulically controlled inlet valve.