Process filtration removes particles, microorganisms, and dissolved contaminants from liquids, gases, and process streams using a graded series of technologies — cartridge, micro-, ultra-, nano-, and depth filtration — sized and integrated into your high-purity water, product, and utility systems. Paul Industries designs, sizes, fabricates, and installs process filtration as part of a single-source sanitary system, tying filter housings and sterilizing-grade filters into ASME BPE piping for pharmaceutical, biotech, cosmetic, and food & beverage facilities across the US East Coast, with more than 30 years of cGMP/FDA-compliant experience.
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How process filtration works
Filtration works by placing a barrier of a defined pore size in the flow path so that contaminants larger than the rating are retained while the process fluid passes through. Different mechanisms dominate at different scales: coarse depth and cartridge filters capture particles by a combination of sieving and entrapment within a thick media bed, while membrane filters — microfiltration, ultrafiltration, and nanofiltration — separate progressively smaller species down to microorganisms, macromolecules, and multivalent ions. The correct choice depends on what must be removed, the required throughput, and where the filter sits in the overall process.
In a real facility, filtration is rarely a single device — it is a train. A typical arrangement uses depth or cartridge prefilters to protect a final membrane, a sterilizing-grade filter immediately upstream of a fill or point of use, and vent filters on tanks and housings. Paul Industries treats filtration as system integration: we size each stage for its duty, select the housing and connection style, and tie the filter into the surrounding sanitary piping so the assembly is drainable, sanitizable, and integrity-testable in place rather than bolted on as an afterthought.
Filtration types by pore size and application
The four membrane and cartridge classes below are defined by the size of what they retain. Most systems combine several stages, using a coarser filter to protect a finer one.
| Type | Typical rating | Removes | Typical application |
|---|---|---|---|
| Cartridge / depth | ~1–100 µm | Particulates, sediment, carbon fines | Prefiltration, feed-water & utility protection |
| Microfiltration (MF) | ~0.1–1 µm | Bacteria, larger particulates, some cells | Sterilizing-grade (0.2 µm), clarification, prefilter |
| Ultrafiltration (UF) | ~0.001–0.1 µm | Viruses, endotoxin, proteins & macromolecules | Endotoxin reduction, product concentration, WFI support |
| Nanofiltration (NF) | ~0.001 µm range | Multivalent ions, small organics, hardness | Softening, partial demineralization, selective separation |
Ratings are approximate and overlap between classes; the practical boundaries depend on membrane chemistry and the manufacturer’s validated rating. Rotary and depth filtration are used where high solids loads would quickly blind a membrane, serving as robust upstream clarification before the finer stages.
Our process filtration services
Paul Industries delivers filtration as part of an integrated sanitary scope, so one team is accountable for the filter and the piping it sits in:
- Filtration sizing & selection — matching filter type, area, and rating to flow, contaminant load, and change-out interval so stages are neither undersized nor wasteful.
- Cartridge & membrane filtration — cartridge, micro-, ultra-, nano-, and depth/rotary stages specified for their duty in the train.
- Sterilizing-grade filters — 0.2 µm (and 0.1 µm) final filters for liquids and vent/gas service, installed so they can be tested and changed cleanly.
- Filter housings & assemblies — sanitary single- and multi-round housings, capsules, and sterilizing vent filters selected for pressure, temperature, and drainability.
- Sanitary piping tie-in — orbital-welded, drainable connections to your high-purity water loops, product lines, and utilities per ASME BPE.
- Integrity testing & validation — filter integrity testing (bubble-point / diffusion / pressure-hold) and IQ/OQ/PQ support so the installed filter is documented and proven.
Industries we serve
We integrate process filtration for pharmaceutical and biotech drug manufacturing (sterilizing-grade filtration of buffers, media, and final product, plus vent and WFI-support filtration), cosmetic and personal-care blending and filling lines, nutraceutical production, and food & beverage plants where clarification and microbial control matter. Each industry differs in fluid chemistry, throughput, and documentation, and we tailor the media, housing, and integrity-test approach accordingly.
Standards & compliance
- ASME BPE (Bioprocessing Equipment)
- Governs the hygienic design, materials, surface finish, and weld quality of the sanitary piping and housing connections a filter ties into — so the installed filter assembly is drainable and cleanable.
- cGMP / 21 CFR 211
- FDA current Good Manufacturing Practice requirements that make filtration a controlled, documented step — the reason sterilizing filters are specified, integrity-tested, and recorded rather than simply installed.
- Sterilizing filtration & integrity testing
- Sterilizing-grade liquid filters are generally rated at 0.2 µm and validated for bacterial retention; each installed filter is verified by a non-destructive integrity test — bubble point, diffusion (forward flow), or pressure hold — following widely used ASTM and PDA technical practice for filter integrity testing.
- IQ / OQ / PQ
- Installation, Operational, and Performance Qualification prove the filtration system was built correctly, operates within its parameters, and consistently performs to specification before routine use.
Why Paul Industries
A filter is only as good as the piping and housing around it — a poorly drained housing or a dead leg upstream of a sterilizing filter undermines the whole stream. Because Paul Industries self-performs sizing, sanitary-piping fabrication, installation, and integrity testing, one team owns the filter and its connections, with no gap between the engineer who sizes the stage, the welder who ties it in, and the technician who integrity-tests it. Our crews have built process-equipment and high-purity systems on the US East Coast for more than three decades, and every weld and test is documented for cGMP traceability. Where public project references are limited by client confidentiality, we provide capability statements, weld and material documentation, and integrity-test and validation deliverables on request.
Frequently asked questions
What filtration do I need for my process?
What is sterilizing-grade filtration and integrity testing?
Do you integrate filtration into existing systems?
How do you choose between a cartridge and a housing?
Do you validate the filtration system?
Which East Coast states do you serve?
Get a process filtration quote
Tell us about your fluid, contaminant, required rating, and flow — a Paul Industries engineer will follow up to discuss sizing, standards, and timeline.
Request a Project Quote or call 201-450-8280