Grating Screens and Filter Screens for Intake and Separation
Screen and filter applications use grating as a precisely spaced slot array rather than a walking surface. The specification is driven by the aperture - not the load - and by the need to keep that aperture constant over years of service, which is why bar screens outperform perforated plate in coarse screening.
Screens built from bar grating
Water intake screens, trash screens, air intake louvres, coarse filters in process lines and separation decks on vibrating screens. Bearing bars are set at a fixed pitch with cross rods welded or swaged, giving an aperture that stays uniform from one end of the panel to the other - something welded mesh struggles to hold after handling.
For water intake, stainless 304 or 316 bars with a smooth profile reduce clogging; for air intake louvres, angled bars create the blade profile that sheds rain.
Aperture, strength and cleaning
Aperture follows the smallest particle that must be retained: 0.5-3 mm for fine process screens, 10-25 mm for intake screens, 25-50 mm for trash screens. Panels are usually supplied in a frame so they can be lifted out for cleaning, and screens in dirty water are designed for backwash rather than manual brushing.
Typical specifications
| Screen type | Bar / aperture | Material | Panel | Use |
|---|---|---|---|---|
| Water intake screen | 3x20 bar, 5-10 mm slot | Stainless 304/316 | Framed panel | River / sea intake |
| Trash screen | 6x25 bar, 20-25 mm | Galvanized / stainless | Framed panel | Channel screening |
| Air intake louvre | Angled bar, 25 mm | Aluminum / galvanized | Blade panel | Plant room, cooling |
| Coarse process screen | 2x10 bar, 1-3 mm | Stainless 316 | Made to order | Chemical / food process |
Related products and applications
Frequently asked questions
What is an accurate screen grating?
A bar screen assembled with a controlled aperture, typically 1-25 mm, used where the slot size must be held precisely - water intake, process filtration or classification.
Bar screen or perforated plate?
Bar screens are stronger for a given open area, easier to clean and hold their aperture under load. Perforated plate gives a finer, more uniform opening but clogs faster and is weaker in large sizes.
How do louvre screens shed rain?
The bars are set at an angle so air passes between them while water droplets hit the blade face and drain down, rather than being carried through by the airflow.
Not sure which profile suits your site? Send the span, load and environment to our engineers and we will return a specification with drawings within one working day. Contact us or see the full product range.