Waterwegen en Zeekanaal NV (W&Z) has been working on renewing the mechanical parts of the lock in Zemst, Belgium, since 2000. This lock is situated in the Brussels-Scheldt Maritime Canal linking Brussels with the river Scheldt, and therefore, the harbour of Antwerp.
In the old intermediate gates, the DN of the butterfly valves was limited, causing the adjustment of the water level to be too time consuming. Therefore, the intermediate gates were not being used. W&Z initiated a new design of the intermediate gates that would bring the filling time down to the half but still keep control of the water level. Aelterman was chosen to manufacture and install the new intermediate gates.
In the new design of the intermediate gates, W&Z chose to place four butterfly valves DN1400 in each gate. The chosen butterfly valve for this installation is a double-flanged type usable as an end-of-line valve (only mounted to a flange on one side). The choice was made for a centric butterfly valve in order to reduce the resistance and the turbulence of the water. Since the medium is channel water, it can contain sand and various impurities. The butterfly valves will have around 10 open/close cycles per day.
