Replacement rotating sieve

Problem or question of the client?

It was necessary to replace the rotating sieve that filters the Scheldt water. The wheel was heavily corroded over the years by the convergence of fresh and salt water in the Scheldt and erosion by the wind. KCD asked us to do this delicate work.
The most important fact was that the coating of the wheel had to meet very strict conditions since the extreme environment (combination of fresh and salt water, erosion, corosion) causes aggressive reactions to the metal. Therefore, repairs to the coating had to be avoided at all times. This meant that no adjustments to the parts could be made on site. This on the otherhand meant that the entire sieve up to and including the last bolt and the smallest part had to be assembled in our workshop to be absolutely sure that each part was correct and fit.

DPG had the great advantage that our workshop is 20 meters high and extremely suitable for pre-assembling and testing such large pieces. Remember that this device has a diameter of 16 meters and a weight of 40 tons.

The second challenge was the element of safety, which meant that with normal assembly, the imbalance in the sieve posed great dangers for the assembly staff. A specific hydraulic drive was developed for this that only served during assembly. This ensured that De Pecker Gent, with a minimum of personnel, carried out the assembly in half the normal time combined with 100% safe working conditions.

Our approach?

We visited the site. The engineers of Doel were uncertain about the dimensions indicated on the original plans. Our team therefore outlined a fully rotating sieve. We custom manufactured and assembled every part in our workshops and then tested it. We also applied some improvements. We conducted a study on the best possible coating for bolts to prevent the internal rusting of the bolts. The decisive factor was the fact that we were able to fully test the wheel in-house and that the hydraulic drive promoted safe working.

End result?

The sieve was fully assembled without a single damage to the coating. The whole was also assembled in a minimum amount of time in order to avoid downtime; we only used half of the usual assembly time. The client has a completely new wheel and will be able to continue for many years to come.