Pre-charging of Hydro-pneumatic Accumulators

Textbook on ‘Hydraulic Accumulators and Circuits in the SI Units’

By Joji Parambath

The textbook presents information on the classification, constructional features, working, and essential terms and definitions, sizing, and safety and maintenance aspects of hydraulic accumulators. The book uses the SI system of units.

Textbook on ‘Accumulators in Hydraulic Systems in the English Units’

By Joji Parambath

Please click on the images to go to the book link of

A hydro-pneumatic accumulator must be filled with dry inert gas, such as the nitrogen gas, while there is no fluid in the fluid chamber. The pre-charge level of the gas medium is an essential parameter for the gas accumulator since the pre-charge pressure along with the accumulator volume determines the maximum amount of hydraulic energy that can be stored in it.

In general, a gas accumulator is pre-charged to a certain percentage of the minimum system pressure, depending upon the type of accumulator and application, and usually as per the recommendation of its manufacturer.

Typically, the pre-charge pressure can be taken as 80 to 90 per cent of the minimum working (operating) pressure of the system for energy storage applications.

The pre-charge pressure for a pulsation compensator or a shock absorber can be taken as 65 to 80 per cent of the minimum operating pressure.

Joji Parambath


Fluidsys Training Centre Pvt Ltd

Bangalore, India

Amazon Author Page URL:

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