Largest fish-safe pumps

Size causes headaches

With as many as six pumps 11.5 meters high with impellers of 4.60 meters, the Den Oever pumping station is one of the largest pumping stations in Europe. For Flowserve, responsible for the development and production of the pumps, they are not only the largest vertical pumps they have made to date, but also the largest fish-safe pumps. An innovation with plenty of opportunities for the future.

To get straight to the point, the scale of the pumps caused Flowserve's engineers some sleepless nights. Bert Waterink, project manager: "The size of the pumps is an enormous challenge. Because of the size, a diameter of 5.50 meters and a height of 11.5 meters, the basic design of our pumps did not suffice. We had to go through and evaluate the design all over again. After all, it has to be right on all sides, both technically and in terms of performance."

Own test basin and test stand

Flowserve specializes in the development and supply of valves, shaft seals and pumps for industries including oil, chemical, energy and the water market. One of its strengths is that it has its own test basin in Etten-Leur for testing the flow to pumping stations and a test rig for testing new impeller designs. "We are unique in that," said Jan Vervoort, sales engineer. "For example, we were able to test both the entire flow and impellers of the pumps for the Den Oever pumping station at scale for efficiency and capacity. A must given the size of the pumps."

Innovative solution for maintenance

In addition to the design, production also caused some headaches. For just find a company that can cast impellers of 4.60 meters and 35 tons. Waterink: "We had this done by a company specialized in casting ship propellers. In any case, good cooperation is essential in a multidisciplinary project like that of the Afsluitdijk. For example, we worked with the Levvel construction consortium (BAM, Van Oord, Rebel and Invesis) and Rijkswaterstaat to find the 'best for project' solution from the very beginning. Due to its size, it is costly to remove the pump from the building in case of maintenance. We came up with innovative solutions for that and the pump is designed in such a way that it is accessible to maintenance personnel and maintenance can be done without dismantling the pump."

Safe for fish

The pumps are extra special because they are also the largest fish-safe pumps in Europe. Fish are as it were guided by the pump. A solution with future prospects according to Vervoort. "For almost all existing pump types for pumping stations, Flowserve has designed a fish-safe solution. Moreover, many pumping stations are basically so good that conversion of existing pumps to a fish-safe design is sufficient to make them future-proof. With a view to sustainability and reducing investment costs, a very interesting option for water boards."