Hydraulic Suction Strainers | Tank Mount & In-Tank

A hydraulic suction strainer sits between the reservoir and the pump inlet, stopping particulate contamination before it reaches the pump. It is one of the most straightforward protection points in a hydraulic system, and one of the most consequential if it is undersized, improperly mounted, or left unserviced.

OFCO manufactures suction strainers across a wide range of configurations: tank mount and in-tank designs, nylon and plated steel construction, and connection options that include hose barb, NPT threaded, SAE straight-thread, and male-to-male styles. Standard flow ratings run from 3 GPM up through 400 GPM for high-volume applications. All products are manufactured in Coshocton, Ohio, under an ISO 9001:2015-certified quality management system.

Use the sections below to find the right strainer for your mounting style, material, and connection requirements. Prefer to talk through the application directly? Call OFCO at 888-354-0291.

Request a Quote Today

Tank Mount Suction Strainers

In-Tank Mount Suction Strainers

The Problem With Splitting High Flow Across Multiple Strainers

The first decision in any suction strainer selection is how the strainer mounts to the reservoir. OFCO offers both major configurations.

Tank Mount Suction Strainers

Tank mount strainers install through the reservoir wall. The suction tube extends below the fluid level inside the tank, with the connection head accessible from the exterior. OFCO’s tank mount line is available in NPT, SAE, hose barb, and male-to-male NPT connection styles, in both nylon and plated steel.

Best for: Industrial power units, mobile equipment, and reservoir designs where external wall access to the connection head is preferred.

In-Tank Suction Strainers

In-tank strainers thread directly onto the suction line inside the reservoir, below the fluid surface. They offer a compact, low-profile installation with no external fittings above the tank. OFCO’s in-tank line includes the H7 and P7 Series in male and female configurations, the PS Series for water and petroleum-based fluids, and the OS Series for high-flow applications up to 400 GPM.

Best for: Applications where reservoir space is limited, inline installations, and high-flow systems where a single large-body strainer is more efficient than multiple smaller units.

Nylon or Steel? Choosing the Right Housing Material

OFCO produces suction strainers with two connector head materials. The screen element (wire cloth over a perforated support tube) is consistent across both. What differs is the connection head.

Pleated suction strainer cartridges with stainless steel end caps

Feature	Nylon (P7 Series)	Metal (H7 / OS Series)
Cost	Lower	Higher
Weight	Lighter	Heavier
Temperature Range	Standard hydraulic operating range	Higher tolerance
Chemical Compatibility	Glass-reinforced nylon, Type 6; verify fluid compatibility	Plated steel; broader fluid compatibility
Best For	General hydraulic systems, cost-sensitive applications, lighter-duty installations	High-flow, high-temperature, structurally demanding applications

Connection types available in nylon: Hose barb

Connection types available in metal: Male to female, male to male, hose barb

Browse by Connection Type

Connection type is often the first thing a system designer or maintenance engineer locks in. Port size and thread standard are usually defined by the existing plumbing before anything else is specified. OFCO’s suction strainer line covers four connection styles.

Hose Barb
Hose barb tank mount strainers are designed for use with soft tubing and compatible with high-pressure hose lines. The barbed fitting creates a secure grip without threads, making them a practical choice for mobile equipment and lower-pressure installations where flexible hose is already part of the system.

Male to Female (Standard NPT and SAE)
Male-to-female configurations are the most common arrangement for tank mount installations. The male thread on the suction tube connects to the reservoir opening, and the female port at the top accepts the suction line from the pump. Available in both NPT and SAE straight-thread versions to match your reservoir and plumbing standards.

Male to Male NPT
Male-to-male NPT strainers thread directly into the reservoir on one end and connect inline to the suction line on the other. Suited for installations where both connection points use male NPT threads and no adapter fittings are preferred.

Threaded (In-Tank, NPT)
In-tank threaded strainers connect directly to the pump suction line inside the reservoir. No external head, no tank penetration above the fluid level. The H7 and P7 Series cover male and female threaded in-tank configurations in both steel and nylon.

The Problem With Splitting High Flow Across Multiple Strainers

Most standard hydraulic suction screens are rated for 3 to 100 gpm. When you need 400 gpm, it’s tempting to tee four 100 gpm strainers together to cover the flow. In practice, every bend, tee fitting, and additional connection in that configuration adds pressure drop.

Fluid traveling around corners loses energy. Multiply that across a handful of fittings, and you’ve built restriction into the system rather than engineered it out. A single, properly sized strainer eliminates all those extra bends. The target pressure drop across a clean screen is 0.2 psid at 150 SUS viscosity and 100 to 125°F operating temperature with 100 mesh media. That number should be achievable whether you’re running 10 gpm or 400 gpm, as long as the strainer is properly sized for the application.

What To Evaluate When Specifying Suction Line Strainers

Matching port size to line size is the starting point. For high-flow installations, these are the factors that determine whether a strainer performs or creates problems:

Flow rate at operating viscosity. Strainer ratings are often published at a reference viscosity. Cold fluid is more viscous, which increases pressure drop, so factor in your actual startup conditions.
Mesh size. OFCO OS Series strainers are available in 30, 60, 100, and 200 mesh. Most hydraulic pump manufacturers specify a minimum for inlet protection in their documentation. Finer mesh increases restriction, so don’t go beyond what the pump requires. For general reference, 100 mesh is the most commonly specified for hydraulic suction applications.
Port configuration. NPT-threaded, SAE straight-thread, hose-barb, and tank-mount styles each suit different reservoir designs.
Housing material. OFCO’s standard suction strainer lines offer connector ends in either nylon or plated steel, depending on the application. The high-flow OS Series uses plated steel connectors throughout for strength and stability.
Mounting location. In-tank suction strainers thread directly onto the inlet line at the bottom of the reservoir. Tank-mount designs bolt through the reservoir side wall and are available in larger sizes.

OFCO OS Series Suction Strainers, Available in 200, 300, and 400 GPM Models

When standard industrial suction strainers top out before your flow requirements do, the OFCO OS Series is where you go next. The OS line comes in three specific flow rate configurations: 200, 300, and 400 gpm, in 5.9″ and 8.1″ diameter bodies. Connections are 3″ and 4″ NPT nipple or coupling. The filter element is stainless steel pleated wire cloth over a perforated support tube, all epoxy-bonded, providing durability and a large surface area in a compact in-tank package. All OS Series units are manufactured by Ohio Fabricators (OFCO) in Coshocton, Ohio, under an ISO 9001:2015-certified quality management system.

Model OS 5.9" Suction Strainer

The 5.9″ OS Series is an in-tank design built for high-flow hydraulic applications when a standard strainer isn’t sized for the job. Constructed with plated steel male and female connectors for strength and stability, it handles high-volume fluid flow while keeping pressure drop in check. An optional bypass valve (3 psi or 5 psi) provides a safety fallback, allowing fluid to pass to the pump if the strainer element needs service.

5.9" OS Series

Hydraulic suction strainers with pleated filter media and threaded ports

Stainless steel hydraulic suction screen with perforated mesh intake

Model OS 8.1" Suction Strainer

The 8.1″ OS Series offers a larger body diameter and greater screen surface area for applications at the higher end of the 200-400 gpm range. Like the 5.9″, it uses plated steel connectors, is designed for below-fluid-level in-tank installation, and includes the optional bypass valve. This is the strainer for large industrial power units, high-cycle mobile equipment, and any system where flow demands exceed what conventional hydraulic strainers can support in a single unit.

8.1" OS Series

Custom High-Flow Strainers from OFCO

If neither standard OS size fits your design, OFCO can build to your specifications. A significant portion of OFCO’s business is custom-fabricated filtration products, and their team works directly from print or performance requirements to produce hydraulic intake strainers that match the dimensional and flow constraints of the application. Lead times are consistently faster than the industry norm.

Talk to Ohio Fabricators About Your Application

OFCO’s team works directly with system designers, maintenance engineers, and procurement buyers to match the right suction strainer to the application. Whether you need a standard OS Series unit from stock or a custom-fabricated solution, call us at 888-354-0291 or contact OFCO online. Standard products ship quickly, and custom orders move fast.

Suction Strainer FAQs

What is the difference between a suction strainer and a pressure filter in a hydraulic system?

A suction strainer sits before the pump on the inlet side and provides coarse protection, typically 74 microns (200 mesh) or coarser. Its purpose is to keep large particles from entering and damaging the pump. A pressure filter is installed downstream of the pump and provides fine filtration, often in the 3- to 25-micron range, to maintain overall system cleanliness. Most properly designed hydraulic systems use both: a suction strainer at the inlet and a pressure or return filter downstream.

What is the difference between a tank mount and an in-tank suction strainer?

A tank mount strainer installs through the reservoir wall. The suction tube extends below the fluid surface inside the tank, with the connection head accessible from the exterior. An in-tank strainer threads directly onto the suction line inside the reservoir, below the fluid surface, with no hardware above the tank. Tank mount designs are well suited for systems where serviceability without draining is a priority. In-tank designs are common in space-constrained reservoirs and high-flow applications where a large-body strainer needs to sit inside the tank.

When should I use a nylon suction strainer instead of a plated steel one?

Nylon connector heads (OFCO P7 Series) are a good fit for general hydraulic systems where cost and weight are considerations and operating conditions fall within the standard temperature range for hydraulic fluid. Plated steel heads (H7 and OS Series) are the better choice when the application involves higher temperatures, higher structural loading, or flow rates that demand the rigidity of metal construction. One note: the maximum temperature rating of any OFCO suction strainer is ultimately set by the epoxy bonding the screen element, not the head material. If your system runs hot, confirm the full assembly rating with OFCO before specifying.

How do I know what mesh size to specify for a hydraulic suction strainer?

Start with the pump manufacturer’s documentation, which typically specifies a minimum recommended inlet strainer rating. For the OFCO OS Series, available mesh options are 30, 60, 100, and 200. The application bulletin references 100 mesh as the general standard for hydraulic suction applications, with a target pressure drop of 0.2 psid across a clean screen at 150 SUS viscosity and 100 to 125°F. Going finer than what the pump requires increases restriction and raises cavitation risk, especially during cold startups when viscosity is elevated.

What happens if a suction strainer becomes clogged?

A clogged strainer restricts flow to the pump, dropping inlet pressure. If inlet pressure drops far enough, the fluid can begin to vaporize, forming bubbles that collapse violently when they reach the high-pressure side of the pump. This is cavitation, and it causes rapid erosion of internal pump components. OFCO’s OS Series addresses this risk with an optional bypass valve at 3 psi or 5 psi, which allows unfiltered fluid to pass through to the pump rather than starving it while the strainer awaits service. That said, a bypass valve is a safety net, not a substitute for a regular maintenance schedule. Inspecting suction strainers at every hydraulic fluid change is a widely recommended practice.

Why is one large strainer better than multiple smaller ones for high-flow systems?

Each bend, tee, and fitting in a multi-strainer parallel configuration adds pressure drop. Fluid loses energy every time it changes direction. A single, properly sized strainer with adequate screen area produces less overall restriction than the equivalent flow split across smaller units with additional plumbing. For systems in the 200-400 gpm range, OFCO’s OS Series handles these flow rates in a single unit rather than requiring a parallel array.

Can OFCO manufacture suction strainers to a custom specification?

Yes. Custom-fabricated products make up a large share of OFCO’s business. We manufacture to customer-supplied prints or performance specifications and can suggest materials and manufacturing alternatives that may reduce cost or improve fit. Material certifications, PPAPs, and pre-production samples are available as part of the process.