In Lausanne, around 2,700 liters of water per second are extracted from Lake Geneva and fed through a heat pump before flowing back into the lake. Some of this water now flows through a Wey DN 1200 knife gate valve, which was installed in one of the main pipes during the last overhaul.

Cleaning the pipes, including the fittings, posed a particular challenge. The invasive quagga mussel has been spreading in Lake Geneva for several years. Pipes leading into the lake must be regularly cleaned of deposits by pigging. The installed valves must therefore be passable for these pigs.

In consultation with the plant manufacturer Bouygues Energies & Services and the clients from Ecole polytechnique fédérale de Lausanne and Université de Lausanne, a special knife gate valve was manufactured in a full bore design, i.e. with a fully open passage. Another knife gate valve in the same design has already been ordered for the upcoming renewal of the second sea pipeline.