An energy storage device that uses compressed nitrogen gas to store hydraulic fluid under pressure is called a hydraulic accumulator. When the hydraulic system needs a quick supply of high-pressure oil, the stored energy is released, guaranteeing the safe, dependable, and seamless operation of vital onboard gear.
An accumulator is essential for emergency operations, pressure stabilisation, and systems needing quick actuation since it offers immediate hydraulic energy, in contrast to hydraulic pumps that constantly provide flow.
A pressure vessel used to hold hydraulic oil under pressure is called a hydraulic accumulator. A rubber bladder, diaphragm or piston inside the accumulator separates compressed nitrogen gas from hydraulic oil. Nitrogen gas functions as a spring, holding potential energy when compressed, but hydraulic oil is nearly incompressible.
Maintaining system pressure, absorbing hydraulic shocks, correcting for leaks, and supplying emergency hydraulic power in the event that the primary hydraulic pump is not available are just a few of the functions of the accumulator.
A hydraulic accumulator works by compressing and expanding nitrogen gas.
Hydraulic oil enters the accumulator when the hydraulic pump begins to run. The pre-charged nitrogen gas is compressed as the oil fills the chamber. Pressure is the energy stored in this compressed gas.
The compressed nitrogen expands quickly if the hydraulic system requires an abrupt increase in flow or pressure, driving the hydraulic oil that has been stored back into the system. Hydraulic power is supplied far more quickly by this instantaneous discharge than by the pump alone.
The pump replenishes the accumulator in preparation for the subsequent operational cycle after the system pressure has returned to normal.
The most commonly used hydraulic accumulators onboard ships include:
Among these, bladder accumulators are the most widely installed due to their reliability, compact design and rapid response.
Hydraulic accumulators play a crucial role in various marine systems where immediate hydraulic power is essential.
In a Lifeboat and Davit system, during a total power blackout, accumulators provide stored hydraulic energy to safely launch lifeboats and rescue boats, ensuring compliance with maritime safety regulations.
Modern electronically controlled marine engines use hydraulic accumulators in their Hydraulic Power Supply (HPS) and Hydraulic Control Unit (HCU) systems. The accumulator delivers the rapid hydraulic pressure required for precise fuel injection and exhaust valve operation.
Steering gear systems rely on accumulators to provide supplementary hydraulic flow during sudden rudder movements. They also act as an emergency pressure source if the primary hydraulic pumps fail, ensuring continued steering capability.
Ship stabilizers use accumulators to deliver quick hydraulic power for fin movement, reducing vessel rolling.
Watertight doors also depend on stored hydraulic pressure to ensure rapid and fail-safe closing during emergencies, helping maintain the vessel’s watertight integrity.
There are many operational advantages to hydraulic accumulators:
A specialised charging equipment should be used to frequently monitor the nitrogen pre-charge pressure. Depending on the manufacturer’s requirements, the pre-charge is usually kept between 80 and 90 percent of the minimum system operating pressure.
Additionally, the diaphragm or bladder should be routinely examined for indications of wear, fractures, or ruptures. Critical hydraulic equipment may fail due to an instantaneous loss of pressure caused by a ruptured bladder.
Rubber components should be gently greased during assembly to prevent damage, and charging valves, seals, and fittings should be checked for leaks. To protect worker safety, the hydraulic system must be fully depressurised and disconnected before performing any maintenance.
Hydraulic accumulators are crucial energy storage devices that increase the safety, dependability and efficiency of a ship’s hydraulic systems. They supply instantaneous hydraulic power when it’s most needed, from main engines and steering gears to lifeboat davits and watertight doors. Hydraulic accumulators are an essential component of contemporary maritime engineering because regular maintenance, appropriate nitrogen pre-charging, and frequent inspection guarantee these vital components continue to function dependably.
A hydraulic accumulator uses compressed nitrogen gas to store hydraulic energy as pressurised hydraulic oil or fluid. It acts as an emergency backup in the event that the hydraulic pump is not available, stabilises system pressure, absorbs hydraulic shocks, and instantly supplies hydraulic pressure during periods of high demand.
Nitrogen gas is employed because it is an inert, non-flammable and dry gas that does not react with hydraulic oil or create corrosion. Nitrogen has no moisture or oxygen, unlike compressed air, which lowers the possibility of oxidation, contamination, and explosion at high pressure.
Numerous shipboard systems have hydraulic accumulators installed, such as:
Regular upkeep consists of:
To ensure dependable and safe performance, adhere to the manufacturer’s suggested inspection and maintenance program.
Disclaimer :- The opinions expressed in this article belong solely to the author and may not necessarily reflect those of Merchant Navy Decoded. We cannot guarantee the accuracy of the information provided and disclaim any responsibility for it. Data and visuals used are sourced from publicly available information and may not be authenticated by any regulatory body. Reviews and comments appearing on our blogs represent the opinions of individuals and do not necessarily reflect the views of Merchant Navy Decoded. We are not responsible for any loss or damage resulting from reliance on these reviews or comments.
Reproduction, copying, sharing, or use of the article or images in any form is strictly prohibited without prior permission from both the author and Merchant Navy Decoded.
Decoded Discount Alert! up to 50% OFF
Decoded Discount Alert! up to 50% OFF
Use Coupon Code Deep50
