Accumulators
Definition
The hydropneumatic accumulator is a device designed specifically for the storage of liquids under pressure. As liquids are, for all practical purposes, incompressible, the objective is achieved by utilising the compressibility of gases.
Construction Features
The EPE bladder accumulator comprises a steel shell, in which is fitted a bladder complete with a gas valve and fluid port with poppet valve.
The Shell
The shell is a pressure vessel forged or fabricated from high grade steel designed and manufactured to meet the relevant international standards. For special applications various surface coatings are available as well as stainless steel construction.
The Bladder
The bladder which separates the gas from the liquid, is made in nitrile rubber in the standard version.
Bladders in butyl, neoprene, ethylene-propylene etc. are available for special uses. The main feature of the EPE bladder, which makes it unique, is the special manufacturing process thanks to which it is produced in one single piece without joints, even in the larger sizes, so as to avoid all the problems which poor gluing may involve.
The Gas Valve
The gas valve is connected to the bladder by a rubber coated washer to ensure a gas tight joint and a non return valve is incorporated for bladder inflation. The bladder, complete with gas valve, is fixed to the accumulator shell by a lock nut, and the assembly is protected by a cover.
The Fluid Port Valve
The fluid port valve prevents the bladder from extruding into the fluid port and at the same time, allows the liquid to flow. In the high pressure range a poppet valve is used, while in the low pressure range a drilled disc is used. In the latter case the pre-charge pressure should not exceed 15 bar
