What Is Liquid Filtration & Filter Bags?
Liquid filtration removes suspended solids from water, chemicals, paints and food streams using filter bags and cartridges, protecting equipment and polishing product to a specified micron grade.
Key Takeaways
- Liquid filter bags span 1-2000 micron, the widest practical range for process fluids.
- Ring styles must match the housing for a leak-free seal.
- PP, PE, nylon and PTFE are chosen by chemical compatibility.
- A graded pre-filter ahead of a fine bag cuts total cost.
Specifications & Comparison
| Micron rating | 1 - 2000 um |
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| Media | Polypropylene, Polyester, Nylon, PTFE |
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| Ring | Snap ring, spring, plastic collar, flange |
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| Temperature | PP <=90 C - PE <=130 C - PTFE <=260 C |
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| Housing | Size 1 / Size 2 bag housings |
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How to Select the Right Liquid Filtration & Filter Bags
- Define fluid, temperature and compatibility to pick media.
- Choose micron grade from the particle size to remove.
- Match ring style to the housing.
- Add a coarser pre-filter to protect the fine bag.
Typical Applications
- Paints, inks and coatings
- Chemicals and solvents
- Process and wastewater
- Food, beverage and edible oil
Frequently Asked Questions
What micron liquid bag should I use?
1-5 um for polishing, 50-200 um for general cleanup, up to 2000 um for coarse strainers.
Which media is chemically compatible?
Polypropylene and PTFE resist most chemicals; verify against the MSDS.
Materials & Chemistry
- Polyester (PET) - the general-duty synthetic, rated to about 130 C, the default for ambient dust and fume.
- Polypropylene (PP) - acid- and moisture-resistant, used to about 90 C in wet or corrosive dust.
- Fiberglass - woven or needled glass fibre for continuous 260 C service on kilns, boilers and incinerators.
- Polytetrafluoroethylene (PTFE) - the most chemically inert media, 260 C, often with a porous membrane laminate.
- Aramid (Nomex) - a high-temperature organic fibre to about 204 C for hot, non-alkali dust streams.
- Polyphenylene sulfide (PPS / Ryton) - alkali- and sulphur-resistant to 190 C for cement and waste-incineration gas.
Standards & Compliance
- ISO 16890 - the current air-filter classification by ePM1, ePM2.5 and ePM10 capture efficiency.
- EN 779 - the legacy grade system (G4, F7, F9) still shown on many equipment datasheets.
- ASHRAE 52.2 - the North American MERV rating method for HVAC filters.
- OSHA 29 CFR 1910.94 - general ventilation and dust-control requirements for workplaces.
- ATEX 2014/34/EU - equipment rules for combustible-dust and explosive-atmosphere areas.
Buyer's Guide & Common Mistakes
- Match media to peak gas temperature with margin; choose finish for the dust (membrane for fine or sticky, anti-static in ATEX zones).
- Size the bag to the tube sheet exactly - wrong diameter or length is the top cause of premature bag failure.
- Watch the air-to-cloth ratio; too high a face velocity blinds the media and raises pressure drop fast.
- Pre-filter bulk solids ahead of the final fine bag to extend life and cut replacement cost.
Authoritative References
Related Products & Terminology
- Pulse-jet baghouse
- Reverse-air collector
- Cartridge dust collector
- Cyclone pre-filter
- Electrostatic precipitator
- Pleated filter element
- Snap-band collar
- Venturi booster
- Solenoid pulse valve
- Differential-pressure gauge
- Air-to-cloth ratio
- Cage wire
- Anti-static ground
- PTFE membrane laminate
- Oil-water repellent finish
Engineering & Evaluation Notes
In a pulse-jet baghouse, short compressed-air pulses travel down a venturi to snap the dust cake off the cloth; reverse-air and shake-deflate designs use gentler, continuous cleaning suited to woven media. Sizing the air-to-cloth ratio and tracking differential pressure protect filtration efficiency and cut lifecycle cost, while correct cage and venturi geometry keep the bag from abrading or collapsing between cleaning cycles.
Last updated: 2026-10-04. Technical review by KOSA Filtration Engineering · LinkedIn. Specifications are typical industry values; confirm exact grades with our engineering team for your duty.
