Diaphragm accumulator

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Schematic representation of how a membrane accumulator works

A diaphragm accumulator , or hydraulic diaphragm accumulator , is a hydraulic pressure equalization device that is used in different versions depending on the application.

Like all hydraulic accumulators , diaphragm accumulators are z. B. used in hydraulic systems, house installations, in process technology , in the oil and gas sector as well as in mobile systems and devices.

Diaphragm accumulators are pressure devices and are subject to, e.g. B. in Europe, the Pressure Equipment Directive 97/23 / EG.

Applications

The different types of construction allow a wide range of uses and applications, such as

• Energy storage including energy reserve for emergencies
• Pressure surge damping, especially when the pump is switched off or started up
• Pulsation dampening as a vibration damper on positive displacement pumps
• Bridging the response time for pumps with variable delivery rates
• Leak loss compensation
• Media separation (liquid on both sides).

Expansion vessel in heaters

→ Main article : expansion tank

Expansion vessel of a gas central heating system

In heating technology , special membrane storage tanks for overpressure compensation in central heating systems are known as "expansion vessels". They are intended to compensate for the temperature-related change in volume of the water in the heating circuit.

Pressure vessels in domestic waterworks

The pressure tank of a domestic waterworks is also a membrane storage tank , in this case it is used to maintain an even water pressure at the tapping point.

Special shape metal bellows accumulator

The metal bellows accumulator is a special form . With this design, the membrane is not made of an elastomer or plastic, but of metal. Metal diaphragms can be designed as corrugated bellows or as welded diaphragm bellows. The advantages are absolute gas tightness and therefore no maintenance and operating temperatures up to 200 ° C or higher. Metal bellows accumulators are mainly used today in aviation, in pump construction and in large diesel engine construction.

Differentiation from the bladder accumulator

Bladder accumulators are constructed in a similar way to diaphragm accumulators, but with them the flexible separating medium is not attached approximately halfway up the container, but centrally at the upper end of the accumulator. As a result, the two fluids are not separated at an "end face" as is the case with a diaphragm accumulator, but the bladder with the gas cushion inside is enclosed by the hydraulic fluid.