Patent ID: 9631455
Date: 2017-04-25
CPC Classifications: E21B,F15B

Claim:
1. A subsea drilling, production or processing actuation system comprising: a variable speed bidirectional electric motor adapted to be supplied with a current and to operatively provide a torque on an output shaft controllable at varying speeds and by direction; a reversible variable speed hydraulic pump driven by said output shaft of said motor; a hydraulic piston assembly connected to said pump and comprising a first chamber, a second chamber and a piston separating said first and second chambers and configured to actuate a valve in a subsea system within a range of motion of said valve; a fluid reservoir connected to said pump and said hydraulic piston assembly; said pump, hydraulic piston assembly and reservoir connected in a substantially closed hydraulic system; and a pressure compensator configured to normalize pressure differences between outside said hydraulic system and inside said hydraulic system; whereby position of said valve within said range of motion is controllable by adjusting said speed and/or said direction of said motor.