How to use the strainer pressure drop calculator
A Y-strainer or basket strainer ahead of a pump or control valve keeps debris out, but a screen that is too restrictive becomes a pressure loss in its own right and blinds off quickly, causing cavitation and starved flow. This tool checks screen open area, net free area and the pressure drop at your design flow in one pass.
Mesh open area is (1 − mesh count × wire diameter)² with the wire diameter in inches. A 20 mesh screen woven from 0.016 in wire is about 46 % open. Multiplying by total screen surface area gives net free area, and dividing that by the pipe cross-section gives the free area ratio. Common practice is at least 2× the pipe area for liquids and 3× for steam or gas service.
Pressure drop uses the flow coefficient relation ΔP = SG × (Q ÷ Cv)² in psi, with the clean Cv taken straight from the manufacturer catalogue. The fouled multiplier sets your cleaning trigger; most plants clean the basket once differential pressure reaches twice the clean value. Fit a differential gauge so you can watch the trend rather than relying on a single calculated number.
Frequently asked questions
Convert it with Cv = Kv ÷ 0.865 and enter the result. Manufacturer catalogues normally list one or the other for each body size and screen option.
No. Going finer drops the open area sharply, which raises pressure drop and shortens the interval between cleanings. Choose the coarsest mesh that still protects the equipment downstream.