HAD - Diaphragm-Type Accumulator

  • Component series 1X and 2X
  • Nominal capacity 0.075 to 3.5 liters
  • Maximum operating pressure 350 bar

One of the main tasks of hydraulic accumulators is, for example, to absorb a certain volume of a pressurized fluid from a hydraulic
system and return it to the system when required.

Because the fluid is pressurized, hydraulic accumulators are regarded as pressure vessels and must be rated for the maximum operating pressure taking account of acceptance standards valid in the country of installation.

In most of the hydraulic systems, hydropneumatic (gascharged) accumulators with separating element are used.

Depending on the design of the separating element, we distinguish between bladder-type, piston and diaphragm-type accumulators.
Hydraulic accumulators basically consist of a fluid and a gas section with a gas-tight separating element. The fluid section is connected with the hydraulic circuit. As the pressure rises, the gas is compressed and fluid gets into the hydraulic accumulator. As the pressure falls, the compressed gas expands and displaces the accumulated fluid into the circuit.

Rexroth Diaphragm Diagram

Diaphragm-type accumulators
Diaphragm-type accumulators consist of a pressure-tight steel vessel (1), which is, in most of the cases, of spherical to cylindrical shape. A diaphragm (2) made of an elastic, flexing material (elastomer) with closing poppet (3) and plug screw (4) is provided as separating element in the interior of the accumulator. These elements comply with Directive 97/23/EC.

- Hydraulic accumulator according to Pressure Equipment Directive 97/23/EC
- Diaphragm material for different applications

Pressure Equipment Directive 97/23/EC of the European Parliament and the Council of 29th May 1997 on the harmonization
of the laws of the member states has been in force since 29th November, 1999. Since 29th May, 2002 hydraulic accumulators may exclusively be placed on the market in a accordance with this Directive.
Diaphragm-type accumulators up to and including 1 liter
The CE Directive has been implemented since November 2001. The accumulators must, however, not be CE-marked. User instructions no. 1 539 929 064 accompany every shipping batch.
Diaphragm-type accumulators greater than 1 liter
The CE Directive has been implemented since November 2001. The accumulators must be CE-marked. They are shipped with operating instructions and a conformity declaration for each series. The conformity declaration includes technical data of the accumulators. The documents accompany each shipping batch.