A dome strainer (Dutch: “bolrooster”) is a hemispherical perforated cover that fits over a drain outlet to catch debris while allowing water to flow through freely. It is similar to a dome wire grate but is typically made from solid sheet material with punched holes rather than woven wire mesh.
How It Differs from a Dome Wire Grate
While both serve the same basic purpose, there are key differences:
- Dome strainer — made from perforated sheet metal or cast metal with uniform round holes
- Dome wire grate — made from woven or welded wire mesh with open grid spacing
The perforated construction of a dome strainer provides finer filtration, catching smaller particles such as sand, grit, and fine organic matter that would pass through a wire grate.
Materials
- Cast iron — heavy-duty, long-lasting, often used in commercial and industrial settings
- Stainless steel — corrosion-resistant, suitable for aggressive or chemical environments
- Galvanised steel — cost-effective for standard applications
- PVC or ABS plastic — lightweight, corrosion-proof, common in residential plumbing
- Brass or bronze — used in decorative or marine applications
Sizes and Configurations
Dome strainers are manufactured to fit standard drain pipe diameters, typically from 50 mm to 200 mm. They may be:
- Press-fit — pushed into the drain opening and held by friction
- Screw-fit — secured with a central bolt or threaded connection
- Clamped — held in place by a surrounding collar or ring
Application
Dome strainers are commonly used in:
- Flat roof drains to prevent blockage of internal rainwater pipes
- Floor drains in kitchens, bathrooms, and industrial facilities
- Basement and cellar drainage systems
- Balcony, terrace, and patio drains
- Car park and loading bay drainage
Regular cleaning is essential to maintain flow capacity. In areas with heavy leaf fall or sediment, quarterly inspections are recommended.
Related Terms
- Dome wire grate
- Floor drain
- Roof drain outlet
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