The short answer
Choose polypropylene filter bags or nylon mesh by how the unwanted material behaves in the actual liquid, not just by its reported size. Rigid particles and deformable gels can behave differently at the same nominal rating, so confirm retention, product quality, and pressure-drop development in a representative trial.
Define what must be removed—and what must remain
Start with the downstream defect: scratched surfaces, blocked nozzles, visible specks, or unacceptable gel particles. Record whether the contaminant is rigid, fibrous, sticky, compressible, or an agglomerate that can break apart. A particle-size report alone does not describe these behaviors.
Also identify valuable material that must pass, such as dispersed pigment or a functional suspended ingredient. A clearer filtrate is not automatically a better product if filtration changes color strength, solids content, or application performance. Establish those acceptance tests before choosing the medium.
Compare construction, not a shared number
Needle felt offers a three-dimensional fiber structure; monofilament mesh provides woven openings. Eaton documents both constructions as distinct product types. This background explains why equal micron labels are not proof of equal separation, but it does not establish which JINLV bag will meet a particular process specification.
A soft contaminant may deform or fragment under the trial conditions. A long rigid fragment can also orient differently from a spherical test particle. Treat these as reasons to test the actual contaminant, not as universal claims that felt always captures gels or mesh always passes them.
Use a decision matrix to plan the comparison
The matrix identifies the next evidence needed. It is not an automatic media selector; chemical compatibility and the complete bag assembly must be acceptable before either candidate enters a trial.
| Observed material | Candidate question | Acceptance evidence |
|---|---|---|
| Rigid grains or chips | Can mesh separate the target without excessive blockage? | Downstream size counts and usable throughput |
| Soft gels or sticky agglomerates | Does felt retain the defect through loading? | Gel-specific inspection at early and late sampling |
| Valuable suspended solids | Does either medium remove saleable material? | Product solids, color or functional test |
| Mixed or variable contamination | Is one stage enough across batches? | Repeated comparison under representative feed variation |
Make the two trials genuinely comparable
Use documented bag identities, verified basket and ring fit, comparable feed, and the same defined operating range. Record flow, temperature, viscosity where relevant, differential pressure, and processed volume. Use paired upstream/downstream samples with timing adjusted for system residence time.
A mesh trial on a clean feed and a felt trial after tank agitation are not comparable. Record feed changes and repeat questionable segments. Inspect the removed bag only after trained personnel have safely isolated and depressurized the equipment under the approved procedure; preserve deposits for investigation when needed.
Accept a balanced result, not the cleanest single sample
Approve against a pre-agreed combination of downstream defect control, product preservation, throughput, and manageable pressure rise. Include startup and later loading points; a good sample near the end cannot erase an earlier unacceptable release.
If neither candidate meets the specification, review upstream contamination control, loading per bag, or another separation stage. Do not keep tightening the nominal rating without checking hydraulic consequences and product loss. Request candidate-specific efficiency data and a defined test method before treating a purchasing label as a performance guarantee.
Your review checklist
- Define the unwanted defect and the valuable solids that must remain.
- Record contaminant shape, softness, stickiness, and feed variability.
- Confirm fluid compatibility, ring dimensions, basket support, and seam construction.
- Agree sampling times, analytical method, and acceptable product changes.
- Log differential pressure and processed volume at matched flow conditions.
- State pass/fail criteria and repeat requirements before the trial.
Limits of this guidance
General media-selection guidance, not a JINLV retention guarantee. Process engineering and quality personnel must approve compatibility, operating limits, trial controls, and any reuse or critical product-contact application.
Questions buyers ask
Does a 50 µm mesh bag equal a 50 µm felt bag?
No. The number needs a retention definition and test conditions, while media geometry and real contaminant behavior can differ. Compare measured outlet quality and throughput under the same duty.
Can the mesh bag be washed and reused?
Do not assume it can. Reuse requires supplier authorization and a qualified cleaning, inspection, and acceptance procedure for the complete assembly and intended process; a visually clean surface is insufficient.
Technical references
References support general principles or the named supplier's own products; they do not certify or validate a JINLV configuration.
AI-assisted technical synthesis of the references below, with editorial checks. This is general procurement guidance, not an independently signed engineering review or a product validation report.
English is the indexing version. Chinese and Indonesian are reading translations of the same article.