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Renovation of a distribution building with butterfly valves DN 500 and DN 800


Trinkwasserversorgung Magdeburg GmbH (TWM) is a drinking water supplier for municipal suppliers, public utilities, associations and industrial companies in the greater Magdeburg area and the surrounding area and is responsible for the production, treatment, storage and distribution of drinking water until it is handed over to customers. TWM’s facilities include 15 waterworks, 760 km of drinking water pipelines, 34 pressure boosting systems and 21 elevated reservoirs. The Colbitz waterworks is TWM’s main waterworks and contributes approx. 70 % to the drinking water supply.

Renovation measure building C

As part of the investment measures to upgrade the piping system, building C, which serves as a drinking water distribution structure for the state capital Magdeburg and the Wanzleben supply area, was renovated.

Due to the technical supply significance of the building C and the complexity of the construction project, the renovation was carried out in several construction phases, but always without interrupting the supply while the plant was in operation. It included the exchange of the pipelines in the nominal sizes DN 800 and the butterfly valves in the nominal sizes DN 500 and DN 800 in the pressure class PN 10.

Installation of butterfly valves with bypass in long overall length

For the butterfly valves required for this renovation, TWM opted for the first-class ERHARD butterfly valves. These were installed in a long overall length, DIN EN 558-R15, with integrated bypass, which is used for filling and discharging pipelines. The bypass to the shut-off also has a soft-sealing gate valve. The nominal diameter of the bypass generally corresponds to 1/10 of the main nominal size, as is the case here.

Both the coating and the material selection of the butterfly valves were designed for underground installation and for drinking water applications:

  • Inside and outside epoxy plastic coating EKB, layer thickness min. 250 µm according to GSK
  • Material housing components made of EN-GJS-400-15, seat rings made of austenitic chrome steel
  • Seals made of EPDM according to DVGW, KTW and UBA
EADIPS Installation of ERHARD butterfly valves mounted on the pipeline

Installation of ERHARD butterfly valves mounted on the pipeline.

EADIPS Butterfly valves after the renovation measure

Final situation after the renovation measure.

Outstanding features of ERHARD butterfly valves

The proven ROCO Wave concept with proven details meets the highest demands for a wide range of applications. ROCO Wave has set standards in terms of efficiency and precision – quality “Made in Germany”:

  • The patented and flow-optimised design of the housing and disc ensures stability and maximum economy. ROCO Wave has been the benchmark for the best Kv values on the market for years.
  • The innovative polygon plug connection of shaft and disc is backlash-free, transmits torque without loss and ensures uninterrupted corrosion protection – another ERHARD patent.
  • The unique SKG gear reliably protects against damage caused by pressure surges and is the ideal solution for safe opening and closing. It is designed and produced by ERHARD.

Extension of the ROCO Wave product range in PN 40

From October 2019, the company will expand the product range of the ROCO Wave double eccentric butterfly valve and now also offers this precise technology for nominal sizes DN 150 to DN 600 in pressure stage PN 40.

With this extension ERHARD continues the ROCO Wave success story of PN 10-25 and complements its standard product portfolio. The first 100 standard valves of this size, respectively pressure stage have already been installed in Germany and Switzerland in the course of this year.