Full flowthrough membrane tanks

Expansion membrane vessels with fixed gas cushion for drinking water systems. The airproof membrane is made from a special butyl rubber and suitable for drinking water. Two connections enabling the flow of water through the tank, meaning there is no stagnant water.

Save valuable drinking water this way: expansion water is no longer lost through a safety valve, but is absorbed by the expansion vessel. The expansion vessel stabilises the drinking water network and reduces switching frequencies. They can be installed at the low pressure and high pressure sides of a pressure boosting system. The mains pressure side is always to be coordinated with the water supply company.


As there are no uniform standards, please observe the drinking water approvals for the individual countries with respect to the selection. These are decisive for the deployment of flowfresh fully flow-through or no flow-through expansion vessel.

  • Drinking water inspection according to the rules of SVGW, ACS, PZH
  • CE design-tested according to PED/DEP 97/23/EC


The expansion vessels are virtually maintenance-free. In general, it is sufficient to observe the flow pressure conditions before the expansion vessel and to check the pre-pressure at least every 5 years. It must always be smaller than the flow pressure. Otherwise, increased bag wear will occur. The A(U)F expansion vessels are equipped with a Hydrowatch HW that signals bag damage.


  • Steel, welded
  • Foot ring for upright assembly and easy  transport
  • Easy mounting thanks to their convenient  eyelets
  • All metallic parts in contact with water in stainless steel
Part number Type Flow P max Diameter (D) Height (H)
    m3/h bar cm cm
0465-PWDO008 ADF 8.10 1⁄2" 0,6 10 34,5 16,6
0465-PWDO018 ADF 18.10 3⁄4" 1,0 10 43 22,4
0465-PWDO025 ADF 25.10 3⁄4" 1,0 10 47,2 25,1
0465-PWDO035 ADF 35.10 3⁄4" 1,0 10 52,1 28
0465-PWDO050 ADF 50.10 1" 1,7 10 58,7 31,7
0465-PWDO080 ADF 80.10 1" 1,7 10 68,7 34,7

Why use full flowthrough membrane tanks

  • Slim cylindrical model
  • Flowfresh full flowthrough
  • Hydrowatch for tightness control of the bag
  • Endoscopic opening for internal inspections
  • PDS Full flowthrough membrane tanks

    Download datasheet (PDF - 1,2 MB)