Why does my filter mesh blind within hours?

The symptom

Differential pressure climbs far faster than the design curve. Cleaning intervals shrink from weeks to hours, and after each cleaning the recovery gets worse. Throughput drops while the pumps work harder.

Root causes

1. 01 Particle size sits right at the aperture: particles wedge into the openings instead of bridging over them, the worst possible match between cloth and contaminant.
2. 02 Wrong weave for the load: an open square weave facing a wide particle distribution captures everything in one plane, so the surface seals itself.
3. 03 No graded prefiltration: a single fine layer is asked to hold the entire dirt load that a coarse guard screen should have taken first.
4. 04 Fibrous or gel-like contaminants smear across the surface, a blinding mechanism that no aperture choice alone can beat.

The mesh solution

• ▸ Shift the rating off the particle peak: slightly coarser or finer than the dominant particle size stops the wedging mechanism.
• ▸ Move from square weave to a Dutch weave: retention happens in the depth of the weave, not on one plane, so the cloth holds more before ΔP responds.
• ▸ For recurring cases, a graded sintered laminate (coarse-to-fine lay-up) multiplies dirt-holding capacity and survives aggressive backflushing.
• ▸ Split the duty: a coarse guard screen upstream takes the bulk load, the fine stage does only the work it is rated for.

Prevention

• ⊕ Have the particle size distribution measured before specifying a rating, not after the third blocked element.
• ⊕ Log ΔP against time from day one: the shape of the curve identifies blinding long before capacity is gone.
• ⊕ Review the weave choice whenever the upstream process changes: a new polymer dose or a new raw material moves the particle spectrum.