Choosing between bag filters and cartridge filters is a fundamental decision for any industrial water or wastewater treatment system. Engineers and plant operators often ask us: which filter type fits best for their process? At CLARIBag, we work closely with clients across water, chemicals, oils, paints, and the food & beverage sector to provide solutions that truly align with their operational needs. In this detailed guide, we’ll compare both technologies, outline their strengths and limitations, and help you navigate this critical choice.
Understanding Bag and Cartridge Filters
Bag Filters: Efficient Workhorses for High-Flow Applications
Bag filters function by passing liquid through a filter bag, capturing solids primarily on the surface or within the depth of the media. Bag filters are renowned for their versatility, fast change-outs, and capacity to handle bulk contaminants.
- Available in multiple media: Polypropylene felt, polyester felt (for depth filtration and higher dirt holding) and nylon mesh (for precision surface filtration).
- Micron ratings: From as fine as 1 micron, up to 1800 micron (mesh type), making them suitable for everything from fine sediment removal to coarse straining.
- Preferred where: High flow rates or heavy solids loading is present, such as in water prefiltration, process side-stream filtration, or protection of pumps and heat exchangers.
- Food & beverage use: All CLARIBag polypropylene felt, polyester felt, and nylon mesh bags meet EC Regulation 1935/2004 for food safety, and each bag is individually wrapped and traceable.
Cartridge Filters: When Absolute Filtration Is a Must
Cartridge filters are typically rigid, tubular elements, available in a range of pleated or depth styles for high retention efficiencies at very fine micron ratings. They are the standard for applications requiring tight, absolute removal efficiencies (often below 1 micron).
- Micron ratings: Down to 0.1 micron for cartridges, suitable for bacteria removal and pharmaceutical-grade filtration.
- Best suited for: Low-flow polishing, critical process water, and where product clarity and sterility are paramount (e.g., beverage bottling, laboratory, microelectronics).
- Change-outs: Cartridges often require more careful handling; change frequency may be lower due to higher surface area from pleating.
Main Differences: Bag Filters vs Cartridge Filters
| Attribute | Bag Filter | Cartridge Filter |
|---|---|---|
| Micron Range | 1 – 1800 micron (mesh); 1 – 200 micron (felt) | Typically 0.2 – 100 micron |
| Flow Rate Capability | High (up to 36 m3/hr/bag for Size 2) | Medium to low (per element) |
| Dirt Holding Capacity | High-depth felt bags, especially with multi-layer construction | Medium-depends on element size and pleating |
| Removal Efficiency | Nominal (up to ~95% for specified micron rating) | Absolute (up to 99.9% removal of specified size particles) |
| Change-Out Procedure | Simple, quick, low-labour; no special tools required | More involved (cartridges may need precise alignment and cleaning) |
| Capital Cost | Lower: Bags and housings are economical | Higher: Cartridges and housings are typically more expensive |
| Best For | Bulk filtration, high flows, larger particles, prefiltration, general process protection | Fine/sterile filtration, product finishing (where regulation, sterility, or product clarity are critical) |
| Typical Industries | Industrial water, wastewater, paint, oil, food/beverage, cooling tower, general manufacturing | Drinking water, pharmaceuticals, microelectronics, bottling, clean-in-place processes |
When to Choose Bag Filters in Your Industrial Application
- Flow Requirements: If your process demands high flow rates (for example, side-stream cooling water treatment or pre-polishing of wastewater), bag filters in Size 1 or Size 2 (up to 36 m3/hr for Size 2) are highly effective and keep downtime to a minimum.
- Solids Load: For heavy particulate loads (like paint overspray, grit in wastewater, or suspended food solids), bag filters allow for longer run times between changes compared to most cartridges.
- Maintenance: Bag systems are extremely user-friendly. Tools like the BFOS bag filter housing opening tool (https://claribag.co.uk/products/bfos-bag-housing-opening-tool-5179360300) reduce operator fatigue and system downtime.
- Food and Beverage Safety: CLARIBag’s food-grade nylon mesh and polypropylene felt bags are compliant with modern European directives, and are individually wrapped for contamination prevention, traceability, and peace of mind.
- Versatility: Broad chemical compatibility is offered. For example, polypropylene felt resists most acids, bases, alcohols, and oils. Nylon mesh can be used for precise removal in water, oils, inks, and even honey. Polyester is excellent for fuels and high temperature applications.
Bag Filter Options for Different Needs
We supply filter bags in a wide range of media and sizes to retrofit most existing housings, and we’re often asked about the best bag for a new application. Here are a few typical examples from our CLARIBag range:
- CB-NM1252HN-FB: For medium-fine straining of water, chemicals, or food liquids where clarity and equipment protection are priorities. Nylon monofilament mesh in a 125 micron rating is ideal for suspended solids, shells, or coarse sediments.
- CB-NM1002HR-FB: 100 micron mesh, reinforced for durability in food and beverage production, or to capture resin flakes and fine silt in cooling water systems.
- CB-NM751WR-FB: 75 micron, suitable for protecting chlorination equipment or for secondary filtration after coarse pre-sedimentation stages.
For very coarse applications, such as clarifying honey or straining out grain husks, we offer up to 1000 micron mesh bags including CB-NM10001WN-FB, all with full food safety clearance.
When Cartridge Filters Are the Better Choice
- Critical Water Polishing: If you require absolute removal of sub-micron particles, bacteria, or for achieving sterile water (such as in final bottling, clean-in-place, or pharmaceuticals), cartridge filters are the gold-standard for regulatory compliance.
- Very Low Turbidity Goals: Where clarity is measured in NTU (Nephelometric Turbidity Units) or where a regulatory standard for particle size MUST be met and documented.
- Low Solids Applications: In clean or lightly-laden water, a cartridge filter's fine rating will last longer and deliver consistent, absolute removal.
FAQs: What Do Our Customers Ask Most?
-
Can I use both filter types together?
Absolutely. Many facilities use bag filters for prefiltration to extend the life of finer cartridge filters downstream, especially in challenging water sources. This staged approach saves money and improves run time. -
How do I pick the right micron rating?
Consider both your particle removal goal and any downstream critical equipment (like UV or RO systems). For prefiltration, 50-200 micron is typical; for fine polishing before membranes, 1-25 micron is standard. Our in-house guide to filter micron selection is always available, or consult our technical team for nuanced advice. -
How does chemical compatibility come into play?
It's vital for long-term performance and safety. Polypropylene felt is resistant to most acids and bases, while nylon mesh excels with solvents and hydrocarbons but isn't ideal for strong acids. Always check your process fluids against our compatibility chart, available in each product's specification.
How to Decide: Steps for Smart Filtration Selection
- Evaluate the solids load and typical particle size in your stream. Don’t forget to check for seasonal or batch process variation.
- Define your desired water quality: equipment protection, product clarity, or regulatory compliance.
- Estimate optimal filter change frequency versus changeout costs and system downtime.
- Always verify chemical compatibility of filter media with process fluids, especially for aggressive chemicals or changing recipes.
- For multi-stage filtration, design your train so bag filters act as prefilters, prolonging the life and integrity of cartridges.
- Get samples or trial filters for challenging or novel process streams-real-world tests yield the best results.
Conclusion: Our Unique Perspective
In our experience at CLARIBag, bag filters provide the best performance for bulk particle load, high-flow systems, with unbeatable ease of maintenance and cost efficiency. They not only protect critical process equipment but also simplify routine operation for site teams, whether it’s process water, recirculating loops, paints, chemicals, or beverage production.
Cartridge filters have their place, particularly where the highest level of clarity or sterility is required post prefiltration. For many applications, combining both technologies gives the best of both worlds.
Not sure which solution fits your needs? Browse our range of industrial filter bags and filter housings, or get in touch with our technical team. We’re always happy to help you navigate the decision in detail, with recommendations grounded in real operational data.
