Hydraulic power unit

Submarine - Mobility

Hydraulic power has proven to be adapted to working in sea water environment, exposed to the immersion pressure and to a corrosive environment for to open or close outside hull doors, deploy or retract equipments. Most, if not all submarines, are then equipped inside the pressure hull with hydraulic power unit(s) to generate hydraulic pressure.
In most submarines, hydraulic fluid is used to deploy or retract the masts in the conning tower, lock the torpedoes launchers doors, operate the windlass, the capstans etc… and depending if the submarine is equipped with these: the bow stabilizers deployment, auxiliary thruster deployment and hydraulic power drive of the auxiliary thrusters if these thrusters are driven by an hydraulic motor.
Hence, the size and power rating of the hydraulic power unit depends very much on the system dispatching hydraulic power, as this determines the pressure and flow rate requirements.
The system is generating pressurized hydraulic fluid through the use of an electric motor coupled to a hydraulic pump; flow rate can be adjusted through the use of variable electric motor drives. Power for the motor is supplied by the submarine batteries which are converted into alternative current by the use of power converters. The entire system is controlled by the use of a Plc cabinet housing the logics which drives both the converters and the servovalves. Additional equipment includes pressure tanks for fluid accumulation & regulation, hydraulic valves for working / stand-by switching as well as other electro-hydraulic devices & sensors.