Set the fluid, strainer body, filter element and screen geometry, then press Calculate. Open-area ratio R and face velocity are derived from the screen dimensions — no vendor datasheet needed for a screening ΔP.
R = A_open / A_pipe
v_face = v_pipe·(f/R)
K_total = K_body + ζ·(f/R)²
Engineering tips
- Body vs element: the body K usually dominates clean ΔP; a coarse perforated screen adds only ~5–15%.
- Low Reynolds is normal: face area is 10–30× the bore, so screens run at Re ≈ 10–100. Fine-mesh element ΔP is a lower bound — use the vendor tested Cv for a datasheet value.
- Fouling: β scales the element only. Above β ≈ 0.4 switch to the rigorous model; alarm ΔP is typically 0.35–0.7 bar.
- Conical caution: a plain witch-hat at h/D = 2–3 only reaches R ≈ 1.6–2.4, below the R ≥ 3 rule of thumb.
Recommended values
- Clean ΔP: Target < 0.1–0.2 bar; size for the fouled ΔP, not the clean value.
- Clean-out trigger: Alarm / clean the element at roughly 2–4× the clean pressure drop.
- Open-area ratio: Temporary start-up cone ≈ 3:1 open:pipe area; permanent basket ≈ 2–3:1.
- Mesh: Add a fine mesh lining over perforated basket for < 1 mm particle capture.
Limitations
- Fouling model: Uniform blockage factor β only — no cake filtration or progressive mesh blinding kinetics.
- Flow field: Assumes even face distribution; real partial blockage causes local velocity peaks and higher ΔP.
About the standards
- Idelchik: Handbook of Hydraulic Resistance.