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Expansion vessels

Expansion vessels are used in non-frequency-controlled pressure boosting systems to limit the switching frequency. The larger the expansion vessel is selected, the less the pumping system has to be switched on. This increases the service life and reduces energy consumption by up to 80%. In addition, pressure surges are minimized in the case of fast-closing consumers or unfavorably routed pressure line systems. For frequency-controlled pressure boosting systems, small expansion tanks are required for correct switching function of the control system. We offer the following expansion vessels:

  • AG-05 and AG-024: for RAINMASTER Favorit-SC series, gas-tight with only max. 2 % pressure loss/year with air filling (according to DIN 4807/3 24 % are allowed, no nitrogen required).
  • AG-060 to AG-500: for pressure boosting systems without frequency converter,integrated valve for refilling the gas cushion, connection set included, easy to maintain, the butyl bladder is replaceable
Material:Butyl rubber
Membrane prepressure P0:P0 = Pe– 0,5 bar
Diameter [mm]150260379450554775
Hight  [mm]30044081591012131460
Weight [Kg]1,63,813,51941,580
max. operating pressure [bar]8810101010
vessel connection AG1"1"1"1"1"1 1/2 "
Type of gas--N*N*N*N*

* Nitrogen

V = 0,33 x QmaxA x (pa + 1) / ((pa – pe) x S x N)

Buffer volume approx.: VBuffer = V (1- pe / pa ), if p0 = pe


Flow rate at design point


Pump number


Switching frequency [e.g. 20/h]


Switch-off pressure


Switch-on pressure



  • Install bleed cock and shut-off valves for maintenance purposes.

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