Understanding the Application of Accumulators

Posted on 05/06/2025 by Fluid Power Journal in Features, Home Header, Recently in Fluid Power Journal, Test Your Skills

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Accumulator circuits store pressurized fluid. They are used for several purposes:

Maintain system pressure.
Absorb hydraulic shocks.
Supplement pump flow.
Provide auxiliary power.
Act as a barrier between dissimilar fluids.

Fig. 1-46 Accumulator Circuit Operation

Auxiliary power: One of the major benefits of using hydraulic accumulators is that they can store energy for later use. There are some functions that must occur, even if there is a power failure or if the prime mover is not functional. Stored energy in an accumulator can be directed through manually operated, or DC solenoid operated valves to safely position equipment or isolate personnel from a dangerous environment.

Some systems have a wide variation in loads or significant dwell time. The addition of an accumulator may allow the system designer to smooth out the power demand by providing an average flow to the system. When more flow is available than is required in a portion of the cycle, the extra volume is stored in an accumulator. When the required flow exceeds the pump flow, the accumulator will make-up the difference with the stored energy.

Safety tip: The accumulator must be completely discharged or blocked out of the circuit before attempting to disconnect any hydraulic lines. Never try to disassemble any weight-loaded, spring-loaded, or gas-charged accumulator without releasing all the pressure (hydraulic and gas) first.

Test Your Skills

1. When servicing an accumulator and the hydraulic pressure gauge reads zero:
a. The gas may still have stored energy.
b. The nitrogen pressure will also be zero.
c. It is safe to remove the end cap.
d. Compressed air can be used to replace the nitrogen.
e. The bladder has ruptured and must be replaced.