Food and dairy engineers routinely face filtration demands at 120 L/min flow, 4.2 bar maximum operating pressure, and 0.5 µm absolute retention for particulate control in pasteurized milk lines. These parameters define the minimum mechanical and hygienic envelope where ourFilter Vessels & Housingsrange must perform without compromise. The selection spans single cartridge vessels (5, 10, 20, 30 and 40 inch), multi-round housings (4 to 18 cartridges), duplex vessels (Size 1–4), bag filter housings (Size 1 and 2), and multi-bag vessels (4 to 23 bags). All are available in Type 304 and Type 316 stainless steel or carbon steel, with NPT (3/4, 1, 2 inch) and flange (2–6 inch) connection options.
Hygienic Integrity Through Material and Finish
316L stainless steel remains the baseline material for food and dairy applications where chloride exposure, cleaning-in-place (CIP) chemical aggressiveness, or extended service life are concerns. Its molybdenum content improves resistance to pitting and crevice corrosion versus 304. Surface finish matters equally: electropolished interiors reduce biofilm adhesion and improve cleanability. We supply all 316L vessels and housings with Ra ≤ 0.4 µm as standard unless specified otherwise. Carbon steel variants require external coating and are limited to non-product-contact utility streams such as compressed air or cooling water.
Connection Architecture and Cleanability
Tri-Clamp sanitary fittings on the 316L SS single cartridge sanitary housing eliminate threaded joints that trap residue. Flanged connections (2–6 inch) provide rigidity for high-pressure duplex vessels but require more disassembly time than clamp-based systems. NPT threads remain acceptable for low-risk utility lines where full CIP is not required. In practice, we typically see operators prefer Tri-Clamp for product-contact vessels handling UHT milk or whey protein solutions — the reduced gasket surface area and repeatable torque control directly lower post-CIP rinse volumes by measurable margins.
Selecting Between Single, Multi-Round, and Duplex Configurations
Single-cartridge vessels suit low-flow, point-of-use protection — for example, final polishing before aseptic fillers. Multi-round housings distribute flow across multiple elements, lowering differential pressure per cartridge and extending service life. Duplex vessels enable uninterrupted operation during element changeout, critical for continuous cheese brine or lactose crystallization lines. A key trade-off emerges when scaling from single to multi-round: increased footprint and higher initial cost at the cost of reduced maintenance frequency and more stable upstream pressure profiles.
Standards Alignment and Verification Pathways
Compliance with 3-A Sanitary, EHEDG, USDA, and cGMP standards is determined by configuration, material, surface finish, and weld quality — not by vessel type alone. Buyers must verify conformance through third-party documentation: review weld procedure specifications (WPS), material test reports (MTRs), and surface roughness certification for each delivered unit. KOSA does not issue certifications; instead, we supply traceable documentation packages aligned with ASME BPE and DIN practices. Request MTRs showing actual chemistry, including Mo and Cr percentages, to confirm 316L grade compliance.
| Configuration | Typical Basket Depth | Max Flow Range (L/min) | CIP Compatibility |
|---|---|---|---|
| Size 1 bag housing | 15 inch | 80–220 | Full |
| Size 2 bag housing | 30 inch | 200–550 | Full |
| Duplex Size 3 vessel | 30 inch | 400–900 | Full |
| Multi-round 14-cartridge housing | N/A | 350–850 | Full |
This table reflects measured performance under standardized CIP conditions.
Application Limits and Exclusions
This selection does not apply to high-viscosity syrups above 15,000 cP or non-aqueous solvents like ethanol blends. It is unsuitable for vacuum filtration or steam sterilization cycles exceeding 135 °C. Avoid using carbon steel bodies in any food and dairy product-contact stream. For dust collection or flue-gas duty, refer to our Dust & Flue-Gas Filtration line — its structural design, sealing strategy, and material allowances differ fundamentally from liquid-handling requirements.
- Verify surface finish Ra values via certified profilometer reports
- Confirm weld purge gas usage and post-weld passivation method
- Require dimensional drawings stamped “As-Built” prior to shipment
For process-critical liquid filtration tasks requiring documented hygienic performance, consult our Liquid Filtration resources. Each Filter Vessels & Housings configuration is engineered to support validation protocols — but only when installed with verified materials, finishes, and documentation. The responsibility for final system qualification rests with the end-user’s quality and engineering teams.
Common questions on filter vessels & housings
How many cartridges should a vessel hold?
Start from the flow per element at the differential pressure you are prepared to run, then round up to the next standard housing: 1, 4, 5, 6, 14 or 18 cartridges. Rounding up costs footprint; rounding down costs change-out frequency.
When is a duplex vessel worth the extra cost?
When the line cannot stop. A duplex body lets one side be opened while the other keeps running, and on a continuous process that matters more than the capital difference. On a batch line it is usually the wrong call.
Does basket depth change flow or dirt holding capacity?
Both, but not in the same proportion. A Size 1 bag with a 15 inch basket and a Size 2 bag with a 30 inch basket are not interchangeable on flow alone: the larger basket buys surface area and dirt holding capacity, and the housing grows with it.