ESB Trash Screens
Norfolk Marine Ltd carried out a pilot scheme involving the removal and replacement of three trash screens which prevent debris entering the upstream intakes of the hydroelectric generating station. Working methods were established utilizing Norfolk Marines staff, diving equipment and floating plant together with the ESB’s staff and trash hoist to successfully complete the project.
The following spring, Norfolk Marine Ltd won the tender to remove, supply and replace the trash screens not previously replaced at the Cliff Generating Station. The company perfected methods utilized in the pilot works to replace the screens to the tender budget and ahead of program. Norfolk Marine Ltd supplied all materials for the project overseeing all QA and testing required. The company acted as construction stage supervisor and underwent safety audits by both the ESB and the H.S.A.
Whilst carrying out the screen replacement, the ESB requested for the divers to carry out an inspection of the upstream dam gates for the turbine intakes one of which had not sealed for over 20 years. This was only possible due to the removed trash screens allowing the diver to gain access to the intake. Cleaning of the gates guides and a number of trial operations lead to the gates sealing and allowing the turbine intake to be pumped dry.