Generality - Principle - Applications

In 1938 Olaer conceived and built the hydro-pneumatic bag-type accumulators (Mercier-Greer license). From there until its entry into the big family Parker in 2013 it remained a leader in the construction and supply of accumulators. The sizing of bag accumulators is based on the Mariotte law, which considers the important difference in compressibility between a gas and a liquid. Hydraulic accumulators are basically divided into three types. Bag, Membrane, Piston accumulators. In bag and membrane accumulators, these are blocked in the body and inflated with nitrogen at a pressure determined according to the work to be carried out and to the application. In piston accumulators the separation of gas (nitrogen) and fluid is carried out by means of a floating piston.
Types of accumulators in production:
MODELS
EHV Series: High pressure bladder accumulators. Forged body without welding. Fluid side anti-extrusion valve. Sturdy nitrogen loading valve. Completely removable battery for overhauling and replacement of damaged parts.
EBV Series: Low pressure bladder accumulators. Forged body without welding. Fluid side window. Sturdy nitrogen loading valve. Completely removable battery for overhauling and replacement of damaged parts.
ELM Series: Membrane accumulators with vulcanized metal anti-extrusion plate. welded steel body. Hexagonal screw for nitrogen loading. NON-repairable accumulators. in case of damage they must be replaced.
EHP Series: Gas-side flanged piston accumulators. Non-welded, bored and ground pipe. Aluminum piston. Nitrogen loading valve. Completely removable battery for overhauling and replacement of damaged parts.

Operation of the gas loaded bladder accumulator is based on the considerable difference in compressibility between a gas and a liquid, enabling a large quantity of energy to be stored in an extremely compact form. this enables liquid under pressure to be accumulated, stored and recovered at any time.

A - Bladder in the Precharge position, wich means that the accumulator only contains nitrogen. The antiextrusion system closes the hydraulic orifice which prevents the destruction of the bladder. In low pressure accumulators the bladder rests against the grid. Maximum pressure differential (P2/P0): 4:1
B - Position at the minimum operating pressure. There must be a certain amount of fluid between the bladder and the hydraulic orifice, such that the antiextrusion system does not close the hydraulic orifice.
C - Position at the maximum operating pressure. The volume difference between the minimum and maximum positions of the operating pressures represents the working fluid quantity.

A - The diaphragm is in the precharge position, wich means that it is only filled with nitrogen. The knob closes the hydraulic orifice and prevents the destruction of the diaphragm.
B - Position at the minimum operating pressure: there must be a certain amount of fluid between the diaphragm and the hydraulic orifice, such that the knob does not close the hydraulic orifice. thus, P0 must always be <P1.
C - Position at the maximum operating pressure: the volume change ΔV between the minimum and maximum positions of the operating pressure represents the fluid quantity stored.

When fluid under pressure enters the fluid side of accumulator, the piston is pushed towards the gas side and the nitrogen gas is compressed.