Design and experimental study of oil-based pressure-compensated underwater hydraulic system

An oil-based pressure-compensated underwater hydraulic system is designed and tested in this article. The underwater hydraulic system is equipped with a pressure compensator so that the tank pressure is always balanced with the ambient pressure. The system pressure is thus built on the ambient pressure. In this way, the underwater hydraulic system can work at any water depth. The steady-state characteristics of a spring-loaded pressure compensator are studied. The pressure compensator, underwater hydraulic power unit and the underwater valve control unit are designed and built. The whole underwater hydraulic system is tested in a high-pressure water simulator with lighting and video system in it. Results show that the underwater hydraulic cylinder can be driven properly under high water pressure, which demonstrates the effectiveness of the pressure compensation in the underwater hydraulic system.