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 Particles close to the aperture size can lodge in the openings instead of bridging over them.
2. 02 An open square weave may blind rapidly at the surface when exposed to a broad particle distribution.
3. 03 Without coarse prefiltration, the full dirt load reaches the fine filter layer.
4. 04 Fibrous or gel-like contaminants can smear across the surface. Changing aperture size alone may be insufficient.

Suitable filter media

• ▸ Assess a rating above or below the dominant particle size to limit particles lodging in the openings.
• ▸ Consider a Dutch weave. Retention also takes place within the depth of the weave, which can improve dirt-holding capacity.
• ▸ For recurring blinding, assess a graded sintered laminate with a coarse-to-fine lay-up. Match dirt capacity and backflush resistance to the process.
• ▸ Where appropriate, use an upstream coarse guard screen to reduce the load on the fine stage.

Prevention

• ⊕ Measure the particle size distribution before specifying the retention rating.
• ⊕ Record ΔP against time from commissioning. The curve can help identify blinding early.
• ⊕ Review weave selection after upstream process changes. A different polymer dose or raw material can alter the particle distribution.