Pump suction strainers prevent debris from entering the pump casing, protecting impellers, wear rings, mechanical seals, and bearings from damage. They are essential for pumps drawing from open tanks, sumps, and pipelines with potential debris contamination.
AQ Process Systems sources and exports foot valve strainers (combined strainer and check valve for well/tank suction), suction diffusers (combining strainer, flow straightening, and support in one unit), and tank suction screens for internal tank mounting. Available in cast iron, carbon steel, and stainless steel.
Proper suction strainer sizing is critical, the strainer must have sufficient open area to avoid excessive suction-side pressure drop, which can cause pump cavitation. We size strainers to ensure the clean-screen velocity is low enough to prevent cavitation at the rated flow.
| Product | Specification | Description |
|---|---|---|
| Foot Valve Strainers | ||
| Foot Valve with Strainer | 2", 12" | CI or SS | Flanged or threaded | Combined foot valve (check valve) and strainer for pump suction from open tanks and wells, prevents backflow and blocks debris. |
| Suction Diffusers | ||
| Suction Diffusers | 2", 24" | Integral strainer + straightening vanes | Suction diffuser combining strainer, flow straightening vanes, and adjustable support in one compact unit, mounts directly on pump suction. |
| Tank & Sump Screens | ||
| Tank Suction Screens | SS mesh | Flat or cylindrical | Various sizes | Suction screens for mounting inside tanks and sumps, preventing debris from entering the suction pipe opening. |
| Sump Basket Strainers | Removable basket | Drop-in sump mounting | Drop-in basket strainers for condensate sumps and hot wells, removable basket for cleaning. |
Debris entering a pump can damage the impeller (erosion, chipping), wear rings (scoring, increased clearance), mechanical seal (abrasion, face damage), and bearings. This leads to reduced pump efficiency, increased vibration, seal leakage, and premature failure. A suction strainer prevents debris ingress at minimal cost compared to pump repair or replacement.
A suction diffuser is a compact fitting that mounts directly on the pump suction flange and combines three functions: straining (internal screen removes debris), flow straightening (vanes eliminate swirl and turbulence from upstream elbows), and support (adjustable foot supports the pump weight). This replaces a separate strainer, flow straightener, and pipe support.
The strainer open area must be large enough to keep the flow velocity through the screen below 0.3-0.5 m/s to avoid excessive pressure drop and cavitation risk. As a rule of thumb, the strainer screen area should be 3-5x the pipe cross-sectional area. We size strainers based on your pump flow rate, NPSH requirements, and fluid properties.
A foot valve is a check valve (non-return valve) installed at the bottom of a suction pipe in an open tank or well. It prevents the suction line from draining back when the pump stops, maintaining prime. A foot valve with integral strainer combines the check valve function with debris filtration. They are essential for suction-lift pump installations.
Yes, if the strainer is undersized or the screen is fouled with debris. A blocked suction strainer increases the suction-side pressure drop, reducing the Net Positive Suction Head available (NPSHa) below the pump's required NPSH. This causes cavitation, vapour bubble formation and collapse inside the pump, causing noise, vibration, and damage. Regular strainer cleaning and correct sizing prevent this.
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