Trash screens, inclined or vertical, exists to prevent waterborne debris (sediment, weeds, timber, animal carcases, litter and household and non-domestic waste) from entering culverts, spillways, penstocks and dam intakes where, to do so, such debris could cause blockages, significant damage or flooding in the forebay. Whilst preventing a subsequent blockage downstream, the trash screen relocates the potential for a blockage to the screen itself where the progressive build-up of debris risks degrading the flow and, in exceptional cases, overtopping of the structure itself. For this reason the screen should be designed so that it can be raked clean of debris (manually or mechanically).
The trash screen design will be dependent on many site-specific factors: from the likelihood of ice to the debris disposal options; from the type and size of debris to the depth of water.
If you are an asset owner you’ll know that screen maintenance obligations are significant and that balancing that requirement with a firm control of operating costs can be challenging.
A fully automated system could provide the most cost-effective solution. KGAL engineers work for energy companies, contractors and other consultants to provide conceptual and detailed designs for new and refurbish screens and offer an asset management service for all hydro-related assets.
For more information fill out our contact form or phone us. You’ll find the contact link at the bottom of this page.The trash racks and rake (screen cleaner) hoist at SSE’s Invergarry hydro power station in Scotland.