Most of us don’t assemble components into systems and subsystems while hundreds of feet under water. So if an assembly will be used at the bottom of the ocean, it must accommodate hydrostatic pressures measured in hundreds or thousands of psi.
To stand up to these pressures, enclosures must either be made extremely strong — thick, heavy, and expensive — or pressure inside the housing must match that of the external pressure. This is where compensators come in.
Compensators apply ambient hydrostatic pressure to the interior of an assembly, say, a hydraulic reservoir. Tobul Accumulator, Bamberg, S. C. is known for its extensive line of accumulators and related products. Tobul also offers SEAsure depth compensators, which can be thought of as a specialized accumulator.
A bladder, which normally would be charged with an inert gas in an accumulator, instead contains hydraulic or other fluid and is connected through a transfer coupling to the assembly that needs to be pressurized. The port that normally would be connected to a hydraulic system is, instead, open to the sea. Hydrostatic pressure of the seawater squeezes the bladder to pressurize the hydraulic fluid.
SEAsure depth compensators are specifically designed for offshore drilling and production applications. They are rated to 1500 psi (103.4 bar) and available in capacities from 2½ to 15 gal (9½ to 57 l). Standard materials of construction include carbon and stainless steel with up to four ½-in. NPT threaded fluid ports (other threads optional) on the transfer coupling.
Of course, Tobul also supplies accumulators as an integral part of the control and operation of subsea drilling and production systems. They are used to ensure sufficient hydraulic power to activate hydraulic actuators and motors, electrohydraulic control pods, blowout preventers, and gate valves for flow control of oil and gas to the surface or other subsea locations.
Click here for more information on Tobul's SEAsure depth compensators or accumulators.