Acting as the first line of defense in fluid and hydraulic systems, suction strainers are specifically designed to protect pumps before any contamination enters the system and reduces their efficiency.

Any suction strainer that is poorly installed, is the wrong size, or has the wrong mesh can disrupt the basic functions of the system, leading to premature pump wear and cavitation.

This blog gives complete guidance about suction strainers, their main types available, and how to size and select one correctly.

What Is a Suction Strainer?

A suction strainer is a mesh or screen installed at the suction inlet that prevents solid debris from entering the pump and damaging it. Its main function is to shield critical pump parts like impellers and mechanical seals from getting jammed or destroyed by foreign objects. In industrial practice, these strainers are installed on the suction side to protect the diaphragm and impellers of the pump from fouling. Moreover, if used with proper mesh size, they can help maintain adequate Net Positive Suction Head (NPSH) so the pump does not cavitate.

What distinguishes suction strainers from suction filters is that the strainers trap particles that are larger, ranging from 50 microns and up, compared to filters, which can trap smaller particles. Strainers, therefore, should be used to deal with gross particles, not as replacements for fine filters.

For tank-mounted and reservoir intake options, browse FilterMart's suction strainers, and see our hydraulic filter guide for how suction protection fits into a full hydraulic filtration setup.

Types of Suction Strainers

Basket Strainers: A cylindrical basket with perforated metal or woven mesh construction, installed in suction piping with a blowdown connection for cleaning. This is the most common configuration in refineries and process plants, and in sizes above 4 inches, a single basket strainer generally creates less pressure drop than a comparable Y-strainer.
Y-Strainers: Named for their Y-shaped body, these have lower dirt-holding capacity than basket strainers and are typically used for lighter-duty suction protection. They are compact and cost-effective but need more frequent cleaning in heavily contaminated streams.
Tank/Sump Suction Strainers: Designed for installation through a tank wall or directly into a reservoir, these have a narrow diameter for standpipe connection or a taller body with larger surface area for high-flow tank suction strainers in hydraulic reservoirs. Also called sump strainers, they're common wherever a pump draws directly from a tank rather than a piped supply line.
Duplex (Twin) Basket Strainers: Two basket wells connected through a diverter valve or handle, allowing flow to switch from one basket to the other. This lets one basket be removed and cleaned while the second stays in service and is mostly used where continuous, uninterrupted flow is required, such as marine lubricating lines or continuously running chemical operations.
Temporary/Startup Strainers: Conical, truncated-cone, or flat-disc screens which are set up temporarily during commissioning/start-up to collect construction debris and are removed after the line has been cleaned.

Suction Strainer vs. Y-Strainer vs. Basket Strainer

Factor	Y-Strainer	Basket Strainer	Tank/Sump Suction Strainer
Dirt-holding capacity	Lower	Higher	Moderate–high, depends on surface area
Typical use	Lighter-duty, cleaner fluids	Moderate to heavily contaminated streams	Direct tank/reservoir draw
Pressure drop (sizes >4")	Generally higher than basket	Generally lower than Y-type	Application-dependent
Cleaning method	Manual or blowdown	Blowdown or basket removal	Removal through tank wall/standpipe
Common install point	In-line suction piping	In-line suction piping, refineries	Through tank wall or top-mounted standpipe

Sizing an Industrial Suction Strainer

When a pump is cavitating, one of the main reasons is the wrong size of strainer. So, besides looking for the perfect material or brand of strainer, these factors must be kept in mind:

Open Area Ratio (OAR): An effective strainer should have 3 or 4 times the open area ratio as compared to the internal pipe's cross-sectional area. This prevents excessive pressure drop by keeping fluid velocity through the screen low.
Allowable Pressure Drop: A new and efficient strainer is designed such that it should not cause more than 2 psi or 0.14 bar pressure drop. General industrial guidance puts the continuous-operation ceiling at 0.5–1.0 bar (7–15 PSI) before cavitation risk rises sharply.
Mesh and Perforation Size: It is recommended to use a coarse filter size on suction strainers, mainly 20 or 40 mesh, and perforated plates with ⅛–⅜ inch openings. This filters large debris without completely clogging the strainer. Permanent centrifugal pump suction guidelines often recommend a standard 40 mesh or coarse perforated support.
Temperature and Viscosity of Fluid: Heavier fluids will cause more pressure drop through the same mesh, and a cold start situation may mean that what functions properly when hot is starving the pump during a cold start.

Industrial suction strainer specifications used in hydraulic reservoirs have port sizes ranging between 1 to 3 inches NPT, mesh sizes up to 120, and flow ranges of about 13 to more than 100 GPM, depending on the size of the port. They are based on your particular pump flow rate and reservoir size.

Selecting the Right Suction Strainer Filter

After choosing the right type and size of suction strainer, the next step is choosing based on these criteria:

Choosing correct micron or mesh rating: In most hydraulic protection pumps, 120–200 micron rating mesh ranges are used. It is recommended to match this to manufacturer recommendations and availability of mesh filters. For more on micron ratings, see what a micron rating is.
Compatibility of Pump Type and Strainer: Different types of pumps like centrifugal, gear, or piston have different requirements for particle size and pressure, so these factors should be looked at by the supplier before installing the suction strainer.
Cleaning Process: Strainers that can be self-cleaned or can be blowdown allow you to remove the filtered accumulated debris without restricting the fluid flow or disassembling the whole piping system.
Installation location in the tank: For tank-mounted strainers, the suction pipe inlet should sit at minimum roughly two pipe diameters above the tank bottom to avoid picking up settled sediment.

Common Sizing Mistakes to Avoid

Sizing for clean-strainer pressure drop only, without accounting for how NPSH margin shrinks as the element loads with debris
Choosing mesh too fine for a centrifugal pump, unnecessarily restricting flow when a coarser rating would protect the pump just as well
Ignoring cold-weather viscosity changes, leading to pump starvation during startup even though the same strainer performs fine at operating temperature
Undersizing open area ratio relative to pipe cross-section, which raises velocity through the mesh and accelerates pressure loss
Mounting a tank suction strainer too close to the tank bottom, drawing in settled solids instead of filtering them out

Frequently Asked Questions

What is the difference between a suction strainer and a suction filter?

The main purpose of a suction strainer is to capture and filter out large particles like physical debris, which are above 50 microns, and keep them away from the pump. On the other hand, suction filters are designed to filter out smaller particles like dust and dirt from pumps and hydraulic systems.

What mesh size should I use for an industrial suction strainer?

The general-service strainer for permanent centrifugal pumps is the 40 mesh (0.42 mm aperture size); a finer mesh is needed for positive-displacement pumps, while a coarser mesh is better suited to heavy-duty centrifugal pumps.

Where should a tank suction strainer be positioned inside the tank?

The suction pipe inlet should sit at least roughly two pipe diameters above the tank bottom to avoid drawing in settled sediment along with the fluid.

How much pressure drop is acceptable across a suction strainer?

A clean strainer should generally cause no more than about 2 psi (0.14 bar); continuous-operation guidance typically caps allowable differential pressure at 0.5–1.0 bar (7–15 PSI) before cavitation risk increases.

Can a suction strainer cause pump cavitation?

Yes, an undersized strainer, one with too fine a mesh, or one that's allowed to load with debris increases pressure drop and reduces NPSH available to the pump, which is a common cause of cavitation.

Find the Right Suction Strainer

A suction strainer only does its job if it is matched to the pump type, flow rate, and debris load it's actually protecting against; sizing by open area ratio, mesh rating, and allowable pressure drop matters more than picking a strainer based on port size alone. Whether you are specifying tank suction strainers for a hydraulic reservoir or an industrial basket strainer for a process line, get the NPSH math right for the dirty-element condition, not just the clean one, and you'll avoid the cavitation and premature pump wear that undersized strainers cause.

Sourcing a suction strainer filter for your system? Confirm mesh rating, open area ratio, and pump compatibility with your supplier before ordering, as these three specs determine whether the strainer protects your pump or becomes the bottleneck itself. Browse our suction strainers, or contact our team for help selecting the right strainer.

Suction Strainers: Types, Sizing & Selection Guide