Industrial Liquid Filter Bags & Cartridges
Replacement liquid filter bags and cartridges for process plants: sizes and housing fit, micron-rating basis, materials, service life and element trials.
Buyer summary
- What it is
- Replaceable filter elements for liquid housings: felt or mesh bags with sealing rings, and depth, pleated or resin-bonded cartridges.
- Main applications
- Coatings, inks and adhesives; chemicals and solvents; process and cooling water; food, beverage and edible oils; pharmaceuticals; electronics process liquids; coolants and lubricants.
- Critical purchasing specifications
- Housing make and model, bag size or cartridge style, and seal type
- Micron rating with its basis (nominal or absolute), test method and efficiency
- Media, ring and seal materials compatible with the liquid and temperature
- Flow per element and terminal differential pressure
- Food-contact or extractables documentation, where required
- Qualification considerations
- Check fit and seal first, because a bypassing fine element performs worse than a sealing coarser one. Compare elements on cost per volume filtered, with logged differential pressure.
- First step
- Describe the liquid, flow, temperature and solids, plus your housing make and model.
- How PAXOMER can assist
- Filter elements are qualified in your housing, on your liquid and at your change-out point. PAXOMER can help record the duty, housing and current element, identify bag and cartridge manufacturers with suitable sizes, ratings and materials, and coordinate trial elements. Manufacturer-level discussions on recurring quantities can follow a documented trial. Manufacturer identification, qualification support and pricing discussions depend on manufacturer confirmation, specifications, quantities and terms.
Detailed technical guidance, data tables, FAQs and technical references follow below.
Regulated uses. Food-contact, drinking-water, medical, pharmaceutical, electrical, fire-rated and other regulated uses need documentation and approvals for the exact product, use and market. This page is general information and confirms none of them; request the evidence in writing.
General technical information published by PAXOMER Inc. to support preliminary material evaluation. It is compiled from the sources cited on this page and has not been independently reviewed or certified by a professional engineer, laboratory or certification body. Values marked typical, illustrative or requiring confirmation are not specifications. Confirm properties, standard editions, regulatory status and suitability for your specific application with the manufacturer and, where the use is regulated or safety-related, with a qualified professional or the relevant authority.
Liquid filter bags and cartridges are replaceable filter elements installed in housings to remove particles from process liquids: coatings and inks, chemicals, water, food and beverage liquids, oils and coolants. Bags are usually felt or mesh sewn or welded to a ring that seals in a bag housing; cartridges are cylindrical elements (wound, melt-blown, pleated or resin-bonded) in single- or multi-round housings. Buyers specify them by size and fit, micron rating and its basis, material, seal, flow and allowable pressure drop, and compatibility with the liquid.
This page is for plant engineers, maintenance teams and purchasing staff who buy replacement elements. It explains element types, how to read micron ratings, the properties that decide service life, and how to trial an element in your housing. It does not state that PAXOMER stocks or has qualified any filter element, and its tables are frameworks unless a value is attributed to a source.
A. Product identity and terminology
1. What are liquid filter bags and cartridges?
They are the consumable part of a liquid filtration system. The housing holds the element and directs flow through it; the element captures particles and is replaced when pressure drop reaches a limit or the collected solids reach the planned amount. Bags are usually used for higher solids loads at moderate fineness; cartridges cover a wider range of fineness and are common for polishing and final filtration.
2. Which element types are used?
| Type | Typical use | Points to evaluate |
|---|---|---|
| Felt bags (polypropylene, polyester) | General process filtration, depth loading | Micron basis, seam type, ring, temperature limit |
| Mesh bags (nylon monofilament, polyester) | Coarse straining, reusable service | Mesh opening, cleanability |
| High-efficiency or multilayer bags | Finer filtration in bag housings | Stated efficiency and test basis |
| Melt-blown and wound cartridges | Depth filtration, prefiltration | Rating basis, density gradient, end caps |
| Pleated cartridges | Higher surface area, finer ratings | Membrane or media type, integrity, efficiency |
| Resin-bonded cartridges | Viscous fluids, higher temperature | Resin compatibility, rigidity |
3. Which terms appear in specifications?
Bag size (#1, #2, #3, #4 and others), ring (polypropylene, polyester, stainless steel, snap band), seam (sewn or welded), micron rating (nominal or absolute), efficiency (for example a stated percentage at a particle size), beta ratio, differential pressure (clean and terminal), dirt-holding capacity, flow per element, cartridge length and diameter, end-cap style (double open end, 222, 226 and others), O-ring material, extractables, and compatibility.
4. Who buys filter elements?
Process and maintenance engineers in coatings, inks and adhesives plants, chemical plants, water and wastewater treatment, food and beverage, pharmaceuticals, electronics, metalworking and oil and gas. Purchasing teams buy recurring replacements; engineers specify new duties or approve alternatives.
B. Properties and performance
5. How are bag sizes and housings matched?
Bag housings accept specific bag sizes, and the ring and seal design must match the housing basket and lid. Published dimensions vary slightly between manufacturers: one distributor lists size #1 at 7.06 in × 16.5 in and size #2 at 7.06 in × 32 in (S1), while one manufacturer's data sheet lists its P1 bag at 7 in × 16 in (S2). Cartridges are specified by nominal length, outer diameter and end-cap style, which must match the housing. Always check against the housing manufacturer's drawing.
Element parameters to specify
Framework only. Except where a source is cited, values are application-specific and must be stated by the element manufacturer and confirmed in your housing.
| Property | Value or range | Unit | Test conditions | Test method | Grade or construction | Source | Verification status |
|---|---|---|---|---|---|---|---|
| Bag size #1 dimensions | 7.06 × 16.5 | in | Distributor's published nominal size | Distributor article (S1) | Size #1 bag | S1 | Manufacturer-specific value (one grade) |
| Bag size #2 dimensions | 7.06 × 32 | in | Distributor's published nominal size | Distributor article (S1) | Size #2 bag | S1 | Manufacturer-specific value (one grade) |
| Polypropylene felt temperature limit | 180 | °F | Maximum listed on one data sheet | Manufacturer data sheet (S2) | One maker's PP felt bag | S2 | Manufacturer-specific value (one grade) |
| Polyester felt temperature limit | 275 | °F | Maximum listed on one data sheet | Manufacturer data sheet (S2) | One maker's PES felt bag | S2 | Manufacturer-specific value (one grade) |
| Micron rating and basis | per duty | µm | Nominal or absolute; test method and efficiency stated | Manufacturer method | Any element | None | Application-specific verification required |
| Terminal differential pressure | per system | bar or psi | Change-out point | Plant specification | Housing and element | None | Application-specific verification required |
6. How should micron ratings be read?
"Nominal" ratings usually describe a partial capture at the stated size, and "absolute" ratings a high capture, but the definitions, test dusts and methods differ between manufacturers. Two elements with the same micron number can perform very differently. Ask for the rating basis, test method, efficiency at the stated size and the test fluid. Multi-pass test methods such as ISO 16889 exist for hydraulic filter elements (S3); process-liquid elements are often rated by the maker's own methods.
7. What decides service life?
Service life depends on solids concentration and particle size distribution, flow per element, viscosity, element surface area and depth, and the terminal differential pressure chosen. Deformable or gel-like particles blind elements quickly; a coarser prefilter can extend final-element life. Record differential pressure against time and volume to compare elements fairly.
8. How is chemical and temperature compatibility checked?
The element media, ring or end caps, seams, adhesives and seals must all resist the liquid at process temperature. Polypropylene suits many aqueous and chemical duties but has a lower temperature limit than polyester; one data sheet lists 180 °F and 275 °F respectively (S2). Solvents, oxidisers and high pH can attack specific materials; ask for compatibility statements for your liquid and run a soak test where in doubt.
C. Manufacturing and processing
9. How are filter elements made?
Felt bags are cut from needle-punched felt, often heat-treated or glazed to reduce fibre migration, then sewn or welded to a ring. Melt-blown cartridges are produced by depositing fine fibres on a core with a controlled density gradient; wound cartridges by winding yarn on a core; pleated cartridges by pleating media around a core and sealing it to end caps. Process control affects consistency of rating, fibre release and seal quality.
10. What installation and change-out practices matter?
Seat bags fully in the basket and check the ring seal; check cartridge O-rings and seats; avoid damaging media during installation. Change elements at a defined differential pressure rather than on a fixed calendar alone, and never exceed the housing or element pressure limits. Follow safe procedures for depressurising, draining and handling elements that contain hazardous liquids.
11. Which problems are common?
| Problem | Possible causes | First checks |
|---|---|---|
| Particles downstream | Bypass at seal, wrong rating, ruptured bag | Seal and ring fit; element integrity; rating basis |
| Short life | High solids, fine or gel particles, undersized area | Prefiltration; element area; flow per element |
| Fibre release | Unglazed felt, wrong media | Media finish; rinse-up |
| Collapsed or burst element | Excess differential pressure, temperature | Change-out point; temperature limits |
| Swelling or degradation | Chemical attack | Compatibility statement; soak test |
12. How should elements be stored?
Store elements in their packaging, dry and clean, away from solvents and direct sun. Keep lots identifiable, especially for food, pharmaceutical and electronics duties where cleanliness and extractables matter.
D. Applications and qualification
13. Where are liquid filter elements used?
Coatings, inks, resins and adhesives; chemicals and solvents; process and cooling water; wastewater; food, beverage and edible oils; pharmaceuticals and cosmetics; electronics process liquids; metalworking coolants and lubricants; fuels and hydraulic fluids.
14. Which requirements depend on the application?
Food, beverage and pharmaceutical duties require documentation of material compliance with food-contact rules in the target market, extractables or rinse-up data and lot traceability. Electronics and fine-chemical duties may need low-extractable or pre-rinsed elements. Define these before comparing elements.
15. How should a buyer select candidates?
- Describe the liquid, temperature, flow, solids and the particle size to remove.
- Record housing make, model and element size or style.
- Ask for elements with stated rating basis, efficiency, materials and compatibility.
- Trial in your housing with differential-pressure logging and downstream checks.
- Choose on cost per volume filtered, product quality and safety.
16. How should an element trial be run?
Install candidate and incumbent elements under the same conditions, ideally in parallel housings or consecutive runs with stable feed. Log differential pressure against time and volume, sample downstream for particles or product quality, and record change-out intervals. Inspect used elements for bypass marks, damage and loading pattern.
17. Which documents should be requested?
Data sheet with dimensions, materials, rating basis and test method; compatibility guidance; temperature and pressure limits; food-contact or regulatory statements with scope; certificates per lot where required; and change-notification commitments.
E. Procurement, comparisons and decisions
18. How do bags and cartridges compare?
| Element | Where it may be preferred | Trade-offs to evaluate |
|---|---|---|
| Filter bag | High solids loads, simple change-out, higher flow per element | Bypass risk at seal, coarser practical ratings |
| Depth cartridge | Wide rating range, depth loading | Multiple elements per housing, disposal volume |
| Pleated cartridge | Fine and final filtration, large area | Cost, blinding with gels |
See also Nonwoven filtration and technical media for media roll goods.
19. How should cost be compared?
Calculate cost per cubic metre (or per batch) filtered: element price divided by volume filtered per element, plus change-out labour, downtime, disposal and product loss. A finer or larger-area element with longer life can cost less per volume even at a higher unit price.
20. What should a filter-element RFQ include?
- Liquid, temperature, viscosity, flow and solids description.
- Required particle removal and rating basis.
- Housing make, model, element size or style and seal type.
- Material preferences and compatibility requirements.
- Regulatory documentation needed.
- Annual quantities and delivery location.
Prepare and submit these through the RFQ brief.
21. Which manufacturer qualification questions should be asked?
Range of sizes and styles that fit your housings; rating methods and test data; material compatibility support; quality controls on seams and seals; lot traceability; manufacturing locations; and change control. PAXOMER does not confirm any manufacturer's capabilities on this page.
22. Which related pages should be read next?
- Guide: Industrial filtration media and filter fabrics
- Related page: Nonwoven filtration and technical media
- Related page: Industrial defoamers and antifoams
Manufacturing Regions & International Supply
Countries where public company or trade sources document manufacturing relevant to Industrial Liquid Filter Bags & Cartridges, with the form of material made there and the date of the evidence. A listing is market context only. It does not indicate a PAXOMER relationship, availability or price.
- China: Filter bag, bag filter housing and strainer manufacturing in Jining. Product manufacturing · Company presentation, 2023 · R54
If you are evaluating manufacturers abroad, list in your RFQ brief the destination market, the documents you require and the delivery terms.
Engineering and purchasing FAQs
Each answer is general technical information, not a specification or a quotation.
What does a micron rating on a filter bag mean?
It indicates the particle size the element is designed to capture, but the definition (nominal or absolute) and test method differ by manufacturer. Ask for the rating basis and efficiency.
Are #1 and #2 bags the same size from every maker?
They are similar but not identical. Published dimensions differ slightly between manufacturers, so check against your housing drawing.
When should I change a filter element?
At a defined differential pressure, or earlier if product quality requires it. A fixed calendar alone can waste elements or risk bypass.
Why are particles getting past a fine bag?
Often because the bag is bypassing at the seal or ring. Check fit and seating before moving to a finer rating.
Can polypropylene bags be used in hot liquids?
Only within the temperature limit stated for that bag and your liquid. One data sheet lists 180 °F for polypropylene felt; polyester felt is often used for higher temperatures.
Can PAXOMER supply filter elements?
This page does not confirm supply. Send the duty, housing details and volumes, and PAXOMER will review whether a suitable manufacturer-development opportunity exists.
Technical References
References below were opened on the access date shown. A source supports only the statement it is cited for. Standards are cited by number and title from public catalogue entries; their full text was not read unless stated.
- S1. What is the standard size of liquid bag filters?. The Cary Company. www.thecarycompany.com/insights/articles/what-is-the-standard-size-of-liquid-bag (opens in a new tab) technical literature · accessed 2026-10-30
Distributor article opened 2026-10-30; cited for nominal bag sizes #1 and #2. Distributor information, not a standard. - S2. Standard felt liquid filter bag data sheet. AJR Filtration (via Filtration World). filtrationworld.com/assets/ajr-standard-felt-liquid-filter-bag-data-sheet-25-8db (opens in a new tab) manufacturer literature · accessed 2026-10-30
Manufacturer data sheet opened 2026-10-30; cited for maximum temperatures of 180 °F (polypropylene felt) and 275 °F (polyester felt). Values apply to that maker's bags only. - S3. ISO 16889:2022 — Hydraulic fluid power — Filters — Multi-pass method for evaluating filtration performance of a filter element. ISO (via Austrian Standards shop), 2022. www.austrian-standards.at/en/shop/iso-16889-2022-2022-01-25~p2866975 (opens in a new tab) standard catalogue · accessed 2026-10-30
Catalogue entry opened 2026-10-30; cited only as an example of a multi-pass element test for hydraulic filters. Not a process-liquid bag standard. - S4. Industrial filtration media and filter fabrics (PAXOMER guide). PAXOMER Inc., 2026-10-30. /products/industrial-filtration-media-filter-fabrics/ technical literature · accessed 2026-10-30
PAXOMER’s own guide; not an external source and not independently reviewed.
Regional manufacturing evidence
Company and trade publications cited in Manufacturing Regions & International Supply. Each supports only the statement it is cited for (checked 29–30 October 2026). Naming a company here does not state or imply a relationship with PAXOMER.
- R54. Filtration Division products and market overview: manufacturing plants including Jining, China (filter bags, bag filter housings, strainers). Eaton (Filtration Division presentation, 2023, hosted by a distributor). grappolo.co.il/_files/ugd/53b987_6790a9c3e75b4f3f8bb409bc16534a34.pdf (opens in a new tab) checked 2026-10-30
Evidence notes and limitations
What the information on this page does not establish. Confirm these points with the manufacturer, the current standard or the relevant authority before relying on them.
- Rating definitions, element behaviour and life factors are general industry practice and not supported line by line by a recorded source.
- Bag dimensions and temperature limits are one distributor's and one manufacturer's published values, not standards.
- This page has not been independently technically reviewed or certified.
Facts checked against the cited sources
- The Cary Company article, the AJR data sheet and the ISO 16889:2022 catalogue entry were opened on 2026-10-30, and the cited values were confirmed against those documents.
Where this connects to the full guide
The primary technical guide behind this page is Industrial Filtration Media And Filter Fabrics. All its topics are indexed below.
Topics in the full guide
- Quick answer
- What does this material system do in an industrial application?
- What is the product, and what function does it perform?
- What types, constructions and grade distinctions are available?
- How do composition and construction affect the material?
- How is the material manufactured and converted?
- Which properties and measurement conditions should the specification include?
- Where is this material used in industry?
- Which requirements depend on the intended application?
- How should buyers select a candidate for the application?
See all 38 topics in the guide
Related guides, comparisons and tools
Glossary: Filter medium · Pressure drop · Filter-cake formation · Filter differential pressure
Tools: Product Finder · Manufacturer Finder
How can I submit an inquiry?
Describe your application, the specifications above and the qualification stage. The material and this page are carried into the form for you. PAXOMER replies by email; the form does not confirm stock, representation or qualification.