How to Compare and Select Cast Simplex Strainers

Cast and molded simplex strainers have a fixed ratio of cross-sectional inlet opening to basket surface area. Custom fabricated strainers can be designed for higher straining ratios. The open area ratio (OAR) helps identify designs that may require less frequent basket cleaning (mesh-lined baskets have lower OAR than perforated).

Cast strainers are mass-produced in foundries with lower labor and material costs, making them significantly less expensive than custom fabricated options. They often weigh 80% or less than comparable fabricated strainers due to thinner walls enabled by foundry molds. However, foundry tooling is expensive to modify, so fabricated strainers are better when custom nozzle orientations, additional ports, thicker walls, or higher straining ratios are needed.

Key Factors to Compare

Basket Design & Surface Area

A larger basket for a given pipeline size maximizes surface area and increases time between cleanings. Slanted entrance ring vs. tubular basket designs can perform differently depending on velocity and particle load.

Flow Coefficient (Cv)

Higher Cv means the strainer can handle a given flow rate with less pressure drop. Cv reflects internal geometry and finish, which also determines basket size. A higher Cv is not always better — it depends on your flow rate and cleaning schedule.

Cover / Closure Style

Compare stud/nut vs. quick-opening designs (yoke clamp, swing bolts, knobs). Quick-opening covers save time and labor but may not suit very hot or hazardous fluids. Design pressure dictates which styles are suitable.

Standard vs. Optional Features

Some manufacturers include threaded taps for differential pressure measurement and vent valves as standard; others charge extra. Venting with a needle valve allows safe, controlled pressure release — especially important with hazardous fluids.

Differential Pressure Monitoring

Use gauges or a differential pressure gauge (with switch/transmitter) to monitor basket condition. Clean when differential pressure rises ~5 PSIG above clean baseline. Avoid exceeding 15–20 PSIG to prevent basket damage.

Get Expert Help Choosing the Right Strainer

Many important selection factors are not obvious from size and price alone. With nearly 30 years of experience, we can recommend the best cast or fabricated simplex strainer design for your specific application, flow rate, and maintenance preferences.

We can also help specify compatible accessories such as differential pressure gauges, vent/drain valves, and isolation valves.

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