Process filtration
Filter media for process filtration, sorted by machine
Process filtration separates solid particles from a liquid or a gas in industrial processes. Sefar manufactures filter cloths, filter belts, bags and ready-made segments for 17 types of process filtration equipment. Bigman is Sefar's distributor in Sweden, Norway and Iceland.
- types of filtration equipment in Sefar's range
- 17
- pore size, filter belts for vacuum belt filters
- 7–160 µm
- continuous operation with X-600 elements
- up to 260 °C
- with local technical service from Sefar
- 26 countries
What process filtration is
Process filtration is the separation of solid particles from a liquid (solid–liquid) or from a gas (solid–gas) in an industrial process. The filter medium decides how many particles are retained, how dry the filter cake becomes, how clear the filtrate is and how long the filter lasts.
Sefar writes that maximum production efficiency and trouble-free operation are essential to lower the customer's total cost of ownership (TCO). According to Sefar, understanding the filtration process is a basic requirement for developing the right filter medium. Sefar has developed filter media from synthetic yarn for decades, and its fabrics are used in thousands of installations worldwide.
Since customers usually know which machine they have, the process filtration pages are sorted by machine type. The table below shows what Sefar supplies for each type.
Machines that Sefar filter media fit
Sefar's process filtration overview brochure (2022) has one page per equipment type. The materials and product families in the table are those Sefar states for each machine.
| Machine | What Sefar supplies | Materials and products |
|---|---|---|
| Filter press | Fabricated filter press cloths, calendered cloths for cake release, non-metallic eyelets | Cloths with FDA and EU food compliance |
| Horizontal vacuum belt filter | Filter belts in double and multi layer weave with ready-made closure | PP, PET, E-CTFE, PEEK. SEFAR TETEX® DLW and SEFAR TETEX MLW |
| Vacuum belt dryer | Dryer belts in open and dense weave, sewn, welded, or heat cut and pressed edge, clipper closure | PET, PPS. SEFAR TETEX DRY |
| Coolant belt filter | Belts for coolant cleaning in metalworking, steel mills and the automotive industry, particle-tight closures | SEFAR TETEX DLW Coolant |
| Centrifuge | Liners, inverting centrifuge bags and centrifuge bags, standard edges or customised design | PA, PP, PET, PEEK. Double layer weave with integrated drainage layer |
| Rotary disc filter, including hyperbaric | Ready-made filter segments and sector covers in monofilament and multifilament | PA, PP, PET. SEFAR TETEX MONO |
| Rotary drum filter | Cloths and belts, including with fish-mouth closure | SEFAR TETEX MONO, SEFAR TETEX MULTI, SEFAR TETEX DLW |
| Pressure plate filters and horizontal disc filters | Cloths and covers with several closure options | PP, PEEK, PA, PET, PTFE. SEFAR TETEX DLW, MULTI and MONO |
| Pressure leaf filters, horizontal and vertical | Welded bags, sealing against the collector, scaling retardant design for minerals | Chosen to suit the process |
| Vacuum leaf filter | Ready-made leaf filter bags in monofilament and multifilament, welded | SEFAR TETEX MULTI, SEFAR TETEX MONO |
| Candle filters | Round woven and welded socks for a larger filter area | PP, PET, PA, PVDF, PEEK, E-CTFE. PEEK and PTFE for extreme chemical environments. SEFAR TETEX MONO |
| Nutsche filter | Cloths with hemmed, taped, twisted or laser cut edge | SEFAR TETEX DLW, MULTI and MONO. PEEK for high temperature |
| Fluid bed dryer | Welded filters without stitching holes, conductive fabrics, customised design | PA, PET |
| Baghouse (dust filter) | Needle felt filter bags, pleated high-temperature elements | SEFAR TETEX NF, X-600 |
| Plansifter, rebolter and centrifugal sifter | Sieving fabrics and ready-made covers for flour mills | SEFAR NYTAL® PA, NYTAL PET-GG, SEFAR NYTAL PA-HD, SEFAR NITEX |
Sefar states that the current product data sheet must be read before use. We can help you with the data sheets.
What Sefar promises in process filtration
Sefar's promises recur in all its brochures: higher productivity, less product loss, longer service life and lower total cost of ownership. This is how Sefar describes the benefits for each machine.
- No product loss: welded filters without stitching holes in fluid bed dryers, pressure leaf filters, vacuum leaf filters and centrifuges.
- Cake release: calendered filter press cloths with special weaves give better cake release than standard cloths.
- Strength: SEFAR TETEX MLW has up to 50% higher mechanical strength and service life than SEFAR TETEX DLW Classic.
- Service life: SEFAR TETEX DRY belts in vacuum belt dryers have a service life of up to 18 months.
- Capacity: X-600 elements give up to 25% higher gas flow in an existing baghouse without modification.
- Safety: conductive fabrics in fluid bed dryers reduce the risk of explosion.
- Lower operating cost: for coolant filters, Sefar mentions longer tool life, among other things.
- Quick installation: ready-made segments, bags and belts with proven closure systems.
The whole chain from yarn to finished filter
Sefar spins its own yarn, weaves, finishes and fabricates. According to Sefar, it is the only manufacturer that still produces from its own yarn to the finished product. This gives full traceability of all critical parts, which Sefar highlights especially for pharmaceuticals and centrifuges.
- Yarn production
- Weaving
- Finishing, for example calendering
- Fabrication: coating, laser cutting, sewing and welding
Laboratory and technical support
Sefar has application laboratories with standard and custom-built equipment that reproduces the customer's filtration process. Local subsidiaries in 26 countries provide technical service.
- Suspension analysis
- Particle size distribution
- Customer-specific filtration tests
- Filter medium recommendation
- Process optimisation
- Root cause and failure analysis, including with a scanning electron microscope (SEM)
Industries and applications
Sefar focuses its process filtration on five industries: chemicals, minerals, environment, life sciences and food. The examples below are taken from the brochures.
| Industry | Example applications |
|---|---|
| Chemicals | Pigments, colours, silicates, zeolites, polymers, catalysts, soda ash, sodium bicarbonate, PTA, petrochemicals |
| Minerals and mining | Titanium dioxide, kaolin and clay, phosphoric acid, iron ore, bauxite and alumina, tailings, coal, cement, lithium brine, potash, rare earths |
| Environment | Municipal and industrial waste water treatment, sludge dewatering, synthetic FGD gypsum, waste incineration, drinking water, recycling |
| Life sciences | Pharmaceuticals, active pharmaceutical ingredients (API), nutraceuticals, agrochemicals, blood separation |
| Food | Cane and beet sugar, starch and gluten, beer, wine, juice, dairy, edible oil, citric acid, pasta, flour |
Food and pharmaceuticals
Sefar states FDA and EU food compliance for cloths for filter presses, vacuum belt dryers, plansifters, rebolters and centrifugal sifters. SEFAR TETEX DRY complies with FDA 21 CFR 177.1630 (PET) and 177.2490 (PPS), Regulation (EC) No 1935/2004 and Regulation (EU) No 10/2011.
For pharmaceuticals there is the SEFAR PHARMA GMP programme. Sefar states GMP-compliant products for baghouses, centrifuges and fluid bed dryers.
How Bigman works with process filtration
Bigman has been Sefar's distributor in Sweden, Norway and Iceland since 1970. We help you choose material and weave for your process and machine.
- Cloth by the metre, or finished parts made to drawing or original.
- Customer stock in Spånga for parts we have developed for you, so your supply never stops.
- The lead time is set once the product has been developed.
Frequently asked questions
Which filtration machines does Sefar supply filter media for?
Sefar supplies 17 types of equipment, including filter presses, vacuum belt filters, vacuum belt dryers, centrifuges, rotary disc and drum filters, pressure plate filters, pressure and vacuum leaf filters, candle filters, fluid bed dryers, baghouses and sifters for flour mills.
Are there filter cloths approved for food contact?
Yes. Sefar states FDA and EU food compliance for cloths for filter presses, vacuum belt dryers and sifters, among others. SEFAR TETEX DRY complies with FDA 21 CFR 177.1630 and 177.2490, (EC) No 1935/2004 and (EU) No 10/2011.
Can the filter medium be tested against our own suspension?
Sefar's laboratory reproduces the customer's filtration process and carries out suspension analysis, particle size analysis and customer-specific filtration tests, and then recommends a filter medium.