Method and device for regulating a pressure in a hydraulic system

In combination with a fluid supply system for operating at least a first actuator in a subsea installation, the fluid supply system comprising a fluid supply line connected to a source of pressurized fluid at a remote location for delivering fluid at a constant pressure to the subsea installation, the improvement comprising a system for regulating the pressure of the fluid delivered to at least the first actuator which comprises:

• a first control valve which is connected to said fluid supply line proximate the subsea installation and upstream of the first actuator;
• an accumulator which is connected to the fluid supply line downstream of the first control valve and upstream of the first actuator;
• a second control valve which is connected between the fluid supply line and a fluid return line downstream of the accumulator and upstream of the first actuator;
• a first pressure sensor for measuring a pressure of the fluid in the accumulator;
• and
• an electronic control unit which is connected to the first pressure sensor and the first and second control valves;
• wherein when the pressure of the fluid in the accumulator is below a desired first pressure range for operating the first actuator, the electronic control unit opens the first control valve to add fluid from the fluid supply line to the accumulator until the pressure of the fluid in the accumulator is within the desired first pressure range;
• and
• wherein when the pressure of the fluid in the accumulator is above the desired first pressure range, the electronic control unit opens the second control valve to release fluid from the accumulator into the fluid return line until the pressure of the fluid in the accumulator is within the desired first pressure range.