Filtration Mechanism And Selection Of Sanitary Filters

A sanitary filter removes solid contaminants from liquid or gas streams through physical interception. The filter element traps particles larger than its pore size while allowing fluid to pass. Pore size determines filtration rating, from coarse straining (100+ mesh) to sub-micron filtration. 316L stainless steel housings with electropolished finish (Ra ≤ 0.4 μm) ensure cleanability and corrosion resistance.

How to select a sanitary filter?

1. Determine filtration goal: strainer (coarse removal) or filter (fine/sub-micron removal).

2. Choose pore size based on particle size distribution and allowable pressure drop.

3. Specify housing: 316L SS with Ra ≤ 0.4 μm electropolished finish for pharma.

4. Select connection type: tri-clamp for quick element replacement, flanged for permanent.

Common Design Pitfalls – Why and How to Avoid

•  Threaded connections: Trap contaminants. → Specify tri-clamp or sanitary flange.

•  Rough surfaces: Harbor bacteria, fail CIP. → Specify Ra ≤ 0.4 μm electropolished.

•  Wrong pore size: Causes high ΔP or lets particles through. → Select based on particle size distribution.

•  Poor drainability: Causes fluid retention. → Specify self-draining design with low-point drain.

Filter vs Strainer – Technical Comparison

A sanitary strainer uses a reusable wire mesh screen for coarse particle removal (down to 40 mesh/420 μm). A sanitary filter uses a disposable cartridge for fine filtration (down to sub-micron). Strainers protect downstream equipment. Filters achieve final product clarity and sterility.

Specifications:

• Strainer: 20-40 mesh (420-840 μm), ΔP < 0.1 bar, reusable

• Filter: 0.2-0.45 μm, ΔP up to 0.5 bar, disposable

Filter integrity validation per ISO 4575. Pore size distribution testing per ASTM E128.

Housing Materials and Specifications

Housings are polished to remove pits and crevices, feature curved corners for cleaning, and use clamps instead of threads.

Sanitary filter housings with electropolished surfaces meet 3-A Sanitary and ASME BPE standards.

Filtration Mechanisms

• Direct interception: Particles larger than pore size are blocked.

• Inertial impaction: Particles deviate and impact the filter medium.

• Diffusion: Sub-micron particles captured through Brownian motion.

A sanitary filter with 316L construction and 0.2 μm pore size achieves sterile filtration. Sanitary filters stainless steel in food processing use 0.45-5 μm pore sizes. Sanitary strainer elements with 20-100 mesh remove coarse particles.

CIP/SIP Requirements

• Ra ≤ 0.4 μm finish for cleanability.

• Self-draining design: No horizontal pockets.

• 316L construction: Resists cleaning chemicals.

• Temperature rating: Up to 150°C for steam sterilization.

• Monitor ΔP; replace element when exceeding 0.5 bar.

Applications

Pharmaceutical & Biotech: Sterile water, bioreactor air, API. 316L, Ra ≤ 0.4 μm, 0.2 μm cartridge, tri-clamp, SIP to 150°C, ISO 4575 validation.

Food & Beverage: Dairy, beer, wine, juice. 316L, Ra ≤ 0.8 μm, 0.45-5 μm cartridge/strainer, clamp, CIP to 85°C, 3-A Sanitary.

Cosmetics: Lotion, cream, toothpaste. 316L, Ra ≤ 0.8 μm, 1-10 μm cartridge, clamp.

Design Summary

A sanitary filter removes particles through physical interception. 316L housing with electropolished finish ensures cleanability and corrosion resistance.

For pharmaceutical: 316L, 0.2 μm cartridge, Ra ≤ 0.4 μm, tri-clamp, SIP to 150°C. Validate per ISO 4575. Replace when ΔP > 0.5 bar.

For food and beverage: 316L, strainer or 0.45-5 μm cartridge, Ra ≤ 0.8 μm, clamp, CIP to 85°C, 3-A Sanitary.

For coarse removal: strainer (20-40 mesh, ΔP < 0.1 bar). For fine/sterile: filter (0.2-0.45 μm, ASTM E128). Sanitary filters stainless steel construction ensures corrosion resistance. Sanitary strainer elements protect downstream equipment. Sanitary filter housings meet 3-A Sanitary and ASME BPE standards.

Sanitary Stainless Steel Clamped Straight Filter

• We manufacture Sanitary Straight Strainer, Sanitary Y type Filter, Hygienic Butt Weld Filter, Sanitary Clamped Strainer, Sanitary Thread Male Filter.
• Filters are widely usde in the auxiliary service for food processing, cosmetic, chenicals and paharmacy industries. Due to its hygienic design, it is maunly used to filter the particulates that destroy pumps and some other equipments. 
• The filter consists of inlet and outlet housing,inner screen mesh to filter the particlates and impurities which can't pass the mesh.

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