Suction-side protection for rotating equipment — sized to the suction condition, not the line size alone.
A piping component installed directly upstream of rotating equipment to remove particulate contamination — welding debris, rust, scale and pipe slag — before it reaches the pump or compressor. Impellers, seals and bearings are precision-machined with tight clearances, so they are far more sensitive to particulate damage than most other equipment in a process system.
Unlike general pipeline protection, suction strainer selection has to account for the hydraulic sensitivity of the suction side. Pressure drop across the strainer directly reduces the pressure available at the equipment inlet — which is why sizing here receives closer engineering attention than elsewhere in the piping system.
Debris entering suction lines can produce impeller wear, seal damage and bearing wear — the risk is highest during commissioning or after piping work upstream.
Any strainer adds pressure drop, reducing the pressure available at the inlet. Suction margins are often already limited, so sizing needs real headroom.
Cleaning normally takes the line out of service unless a duplex arrangement is used. Basket access has to be planned into the layout, not added later.
The strainer is positioned directly upstream of the inlet, with basket or screen sizing based on the required flow rate and an allowable suction-side pressure drop established for that specific application. Filtration rating is selected to suit the expected particulate size and the equipment's sensitivity, balanced against the pressure-drop and dirt-holding implications of a finer screen.
Body orientation and connection type are arranged to suit the suction piping layout, with attention to maintaining stable, non-turbulent flow approaching the inlet. Where interruption for cleaning is not acceptable, a duplex arrangement keeps one chamber in service while the other is drained and cleaned.
Six governing inputs, one evaluation, four engineered outputs. On suction service the allowable pressure drop and NPSH-related constraints carry more weight than anywhere else in the line.
Pressure drop is one of several contributors to available suction pressure — it is evaluated against the equipment's suction hydraulic requirement, not in isolation.
| Requirement | Possible Solution |
|---|---|
| Compact installation, moderate dirt load | Y Strainer · Tee Strainer · Wafer Strainer |
| Higher dirt-holding capacity required | Basket Strainer |
| Continuous operation, no acceptable downtime for cleaning | Duplex Basket Strainer · Automatic Strainer |
| Temporary commissioning-only protection | Temporary Cone Strainer |
No single strainer type is universally correct for suction service. Final selection depends on flow rate, allowable suction-side pressure drop, line size, fluid properties, filtration requirement and the maintenance philosophy for the specific installation.
Send these twelve and we can size a suction strainer properly. Partial data is fine — we will tell you what is missing.
Suction strainer bodies, baskets and internals are selected for compatibility with the process fluid and service conditions, in cast or fabricated construction depending on the application, line size and project requirements. Specific material grades and construction methods should be confirmed against the actual fluid, pressure and temperature conditions for each project — material selection is application-specific rather than fixed.
Install with adequate straight-pipe run and clearance so the basket or screen can be removed without disturbing suction piping alignment. Establish cleaning frequency from observed pressure-drop increase rather than a fixed interval. Where the line cannot tolerate an out-of-service period, consider a duplex arrangement at design stage rather than adding it later.
Directly upstream of the pump or compressor inlet, with enough straight pipe run and access clearance to remove the basket or screen for cleaning without disturbing suction piping alignment.
No. A strainer does not prevent cavitation. What it does is add pressure drop on the suction side, which reduces the pressure available at the pump inlet. Because of that, strainer pressure drop must be accounted for in the suction-side hydraulic evaluation alongside static head, line losses and fluid vapour pressure.
Cleaning frequency depends on debris loading. It is better established from the observed pressure-drop increase across the strainer than from a fixed calendar interval alone.
Where the line cannot tolerate an out-of-service period for cleaning. A duplex arrangement lets one chamber stay in service while the other is drained and cleaned — but it should be specified at design stage rather than retrofitted.
Not automatically. A finer filtration rating increases pressure drop and reduces the time between cleanings for the same dirt load. The rating should be matched to the equipment's sensitivity and the expected particulate size, not simply minimised.
Flow rate, suction line size, fluid and service, operating and design pressure and temperature, allowable pressure drop, required filtration rating, material requirement, end connection, orientation and your maintenance philosophy.
Send flow rate, suction line size, fluid, pressure, temperature, allowable pressure drop and filtration requirement — we will come back with a configuration and sizing basis.
Submit RequirementWorking through a suction-margin problem, or unsure whether duplex is justified? Describe the application and we will work through the selection with you.
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