FABRIC FILTER BAGS

Content Filter media for dedusting Fibers & Technologies Type of Bags Needle Felts Woven Fabrics Comparison between Needle Felt & Woven Fabric Bags Manufacturing Final & Surface treatment Bag properties & Tests Bag Failures Applications Advanced Technology

Filter media for dedusting Textile filter media starting from fibers Textile Technologies usually applied: Spun bonding Spun laced Thermal bonding Chemical bonding Warp-weft weaving Needling yarn→ assembling→ twisting→ warping→ weaving→ tentering (water repellent, acid resist, germ resist, antistatic) → cutting→ inspection→ warehousing

Fibers & Technologies Polyester Polyacrylic (homopolymer & copolymer) Metaramid (Nomex, Conex) Polyimide (P84 ® ) PPS (polyphenylene sulphide) PCT (polycyloexilentereftalate) Polypropylene (PP) Polytetrafluoroethylene (PTFE) Glass Polyamide (PA)

Type of Bag Materials

Needle felts A pulse-jet baghouse generally filters more air per cloth area (higher air-to-cloth ratio) than a shaker or reverse-air unit. Felted bags should not be used in high humidity situations, especially if the particles are hygroscopic (these particles have an affinity to absorb moisture and thus become sticky). Clogging or blinding could result in such situations. Felted filters are usually used in pulse-jet baghouses

 Staples  Scrims  Needle  Loom state felt NeedleFelts processing

Woven Fabrics Woven filters have open spaces around the fibers. The weave design used will depend on the intended application of the woven filter. Different weaving patterns increase or decrease the open spaces between the fibers. This will affect both fabric strength and permeability. A tight weave, for instance, has low permeability and is better for the capture of small particles at the cost of increased pressure drop. The true filtering surface for the woven filter is not the bag itself, but the dust layer or filter cake. The bag simply provides the surface for capture of larger particles. Particles are collected by impaction or interception as the open areas in the weave are closed. This process is referred to as sieving.

Woven Fabric Features

Comparison between Needle Felt & Woven Fabric > Baghouse Operating Type > Abrasion Resistance Needed > Resistance to Cleaning Energy > Gas Stream Chemistry > Air-to-Cloth Ratio Development of Woven Fabric Woven or Felt Selection Considerations Fibre glass <260° C Homopolymer Acrylic (PAN) <130° C Surface Foam Coated PAN <130° C Polyphenylene Sulfar (PPS) <190° C Blended PPS and PAN <135° C Chemical Treatments Development of Needled Fabrics Homopolymer Acrylic(PAN) <130° C Polyphenylene Sulfar (PPS) <190° C PPS With surface Treatments <190° C PPS with PTFE encapsulation <190° C PPS with Blended or capped webs (P84) <190° C PTFE (PTFE) <260° C

Bags Manufacturing Longitudinal cutting Stitched Seam Thermowelded Seam Tubing

Bags Manufacturing Bag Top Design Bag Bottom Design

Surface treatment & Final Finishing Needled Fabric with untreated surface Needled Fabric with Singed surface Commonly Treatment

 standard heat setting  flame singed on one side or on both sides  antibacterial impregnation*  antistatic effect by steaming aluminium onto the dust side  antistatic by the admixture of stainless steel fibres according to DIN  antistatic by the admixture of epitropic fibres according to DIN  antistatic by the admixture of stainless steel + epitropic fibres according to DIN  flame retardant Polyester  flame retardant impregnation  surface protection against sparks by a carbon fleece needled onto the dust side  surface protection against sparks by a microporous foam coating carbon powder  smoothening of the dust side by calendering: light, medium & strong  microporous foam coating on the dust side, for abrasive dust + high temperature  microporous stratification of Polyamide  impregnation that renders the pleating of needlefelts  oleophobic, hydrophobic, antiadhesive treatment giving resistance to acids and alkalis  deep coating on Teflon® basis giving resistance to acids and alkalis  microporous surface coating on Teflon® basis providing resistance to acids and alkalis and facilitating the cleaning of the filter bags  microporous PTFE membrane Available Treatment List:

Bag properties & Tests Bag Properties Test Weight ASTM D3776 Construction A. Yarn Count ASTM D3775 B. Type of Weave ASTM D579 Thickness ASTM D1777 Tensile Strength ASTM D5035 Mullen Burst ASTM D3786 Permeability ASTM D737 Organic Content (LOI) ASTM D578 MIT Flex ASTM D2176 Filtration Performance ASTM D6830 Width ASTM D3774 Water Repellency ASTM D2721 Surface Resistance STM Volume Resistance STM Two-Point Resistance STM 11.13

Bag Failures HydrolysesBumpingCage EffectMisalign Blow pipe Thermal EffectPinchingLengtheningFlow abrasion Poor SeamPinholesTop Abrasion Clean side Contamination

Applications (Cement Plant) QUARRYING / GRINDING HOMOGENIZATION Raw Material

Applications Coke Mill Cement Kiln

Applications Cement Packing / Shopping

Advanced Technology

Questions