A hydraulic accumulator is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source. In this case the external source is plastic bladders filled with high pressure Nitrogen gas. An accumulator enables a hydraulic system to cope with extremes of demand using a less powerful pump, to respond more quickly to a temporary demand, or power the yacht’s hydraulic systems when the yachts main engine or pumps are not capable of providing the power.
A compressed gas accumulator consists of a cylinder with two chambers that are separated by an elastic diaphragm, a totally enclosed bladder, or a floating piston. One chamber contains hydraulic fluid and is connected to the hydraulic line. The other chamber contains an inert gas under pressure (typically nitrogen) that provides the compressive force on the hydraulic fluid. Inert gas is used because oxygen and oil can form an explosive mixture when combined under high pressure.As the volume of the compressed gas changes, the pressure of the gas (and the pressure on the fluid) changes inversely. As part of other work being done on the yacht, it was necessary for us to relocate five of the cylinders on this eight part system. Relocating part of the system required us to refabricate new brackets that hold the cylinders as well as re-plumb the hydraulic tubing to adjust to the new layout.
We also replaced a failed, leaking bladder in one of the accumulators before re-pressurizing each of the units to 1,250 PSI.
All this work requires very specialized equipment and knowledge to ensure the work is done right and that the hydraulic accumulator is ready when you need it most.