Felt filter bags are the workhorse of industrial liquid filtration: depth-loading media that captures solids throughout its thickness, tolerates high dirt loads, and costs less per gallon filtered than almost any alternative. Universal Filters manufactures felt bags in polyester, polypropylene, and Nomex, in micron ratings from 1 to 200, in all standard sizes and custom dimensions.
Media Selection
| Media | Micron range | Max temp | Best for |
|---|---|---|---|
| Polyester felt (PE / PEG) | 1–200 µm | ~275°F | General purpose; mild chemicals, water-based fluids, coatings |
| Polypropylene felt (PO / PG) | 1–200 µm | ~200°F | Acids, bases, aggressive chemicals where polyester degrades |
| Nomex® felt (HT) | 1–100 µm | ~450°F | High-temperature service; hot oils, quench baths |
Glazed (singed) finishes for cleaner cake release, and FDA-grade variants of both polyester and polypropylene for food, beverage, and bottling — with vendor certificates of conformance on file.
Polyester Felt Specifications
| Micron | Weight (oz/yd²) | Thickness (in) | Air perm. (CFM) |
|---|---|---|---|
| 1 | 11.5–13.5 | 0.070–0.100 | 20–50 |
| 3 | 11.0–13.0 | 0.065–0.100 | 20–60 |
| 5 | 9.0–11.0 | 0.060–0.090 | 70–130 |
| 10 | 9.0–11.0 | 0.060–0.090 | 80–150 |
| 25 | 9.0–11.0 | 0.060–0.090 | 140–220 |
| 50 | 9.0–11.0 | 0.065–0.095 | 150–240 |
| 75 | 9.0–11.0 | 0.070–0.100 | 190–280 |
| 100 | 9.0–11.0 | 0.070–0.100 | 200–300 |
| 200 | 11.0–13.0 | 0.110–0.145 | 325–475 |
Polypropylene specifications are similar at slightly lighter weights. Full datasheets available on request.
Construction Options
Sewn with galvanized steel, stainless, polypropylene, or nylon rings; plastic flange tops; drawstring or blank tops; fully welded construction for zero-bypass applications. Handles and pull tabs available.
📄 Download the Felt Filter Bags spec sheet (PDF)
Ready to price a felt bag? Call 800-554-8555 or request a quote — include micron, size, and media (or just the part number on your current bag).