FILTRATION TERMS
AIR PERMEABILITY: Called Frazier or Frazier Number, it is the ease in which air will pass thru the fabric and is the measure of the volumetric flow rate of standard air expressed in cubic feet per minute (CFM) passing thru a square foot of fabric with a resistance to flow or static pressure (SP) of 0.5 inches water column (w.g.).
BASIS WEIGHT: Weight of a unit area of fabric usually expressed as ounces per square yard.
BATT: Continuous web or layer of fibers.
CALENDAR: Compressing the fabric between rollers to improve the density.
DENIER: Weight in grams of 9,000 meters, approximately 10,000 yards, of a single fiber.
DUAL-DENSITY: Joining fibers of different weight by blending or layering into a single fabric.
FIBERS: Single slender elongated natural or synthetic filament.
GROUND WIRE: A copper or stainless wire sewn into the seam of the filter on the vertical seam to aid in static dissipation.
LIQUID FELT: Micron rated felt for liquid or fluid applications.
MEMBRANE: A microscopic layer of PTFE laminated onto a substrate of woven or non-woven fabric.
MULLEN BURST STRENGTH: Indicator of fabric strength and measures in pounds per square inch (PSI) of the fabric’s ability to resist rupture.
MULTI-LAYERED: Joining layers of different weight or type of fibers into a single fabric. This is sometimes called capped or dual density fabric.
NEEDLEFELT: Non-woven fabric of typically synthetic fibers that is formed when barbed needles move thru multiple batts of loose fiber to entangle and interlock the fibers and is then heat-set to produce a fabric with excellent filtration characteristics. The batts are sometimes placed on a reinforcing scrim and needled together.
SATEEN: Process where woven produce is “mercerized” to improve sheen and strength of fabric or media.
SEAMLESS: Method of manufacturing a woven product. Media is produced in a tube with no seam in the length of the filter.
SELF-SUPPORTING or UNSUPPORTED: Needlefelt is manufactured in the absence of a scrim. Using more recent technology this method has produced media as strong as the older scrim technology.
SCRIM: A mesh product is needled with the fibers to aid in material strength.
SHAKER FELT: Needlefelt specifically designed for use in shaker dust collectors. Media has higher pore volume, higher efficiency, and lower emissions than woven or knit fabrics.
SUPPORTED: Felt fabric manufactured with a scrim.
THICKNESS: Measure of the thickness of the fabric under a specific load of compression.
WEIGHT: Measure of the average weight of the fabric usually expressed in ounces per square yard.
WOVEN FELT: Process of weaving individual strands of material into a media.
MEDIA STYLES AND CHEMICAL FINISHES
ACRYLIC FOAM COAT: Foam coating is applied to a needlefelt material to aid in dust cake release.
ANTI-STATIC: Stainless is blended in with the other fibers during needle felting process to aid in static dissipation.
EGGSHELL: Fabric passes thru hot calendar rollers to produce a smooth eggshell like surface.
FLAME RETARDANT: Applied to a needlefelt material to aid in reduction of collector fires. Hot particles will usually burn a hole in the media, but treatment will reduce the risk of collector fires.
FOAM-COATED PTFE: Micro foam surface coating that provides a high degree of surface separation excellent for cake release, and aids in finer filtration of dust particles.
GLAZE: After media is singed it is passed under pressure rollers in a calendaring process.
OLEOPHOBIC/HYDROPHOBIC (Fluorocarbon Resin): This treatment is applied in an impregnation process fluorocarbon resin. Finished fabric has good water and oil resistance, as well as chemical resistance.
PLAIN: Needled media with microscopic fibers protruding outward from the surface of the fabric. Fuzzy finish.
SILICON EMULSION: Silicon treatment that coats each fiber to improve dust release.
SINGE: Passing the needlefelt material over an open flame to burn off loose fibers. Process produces a surface that aids in cake release.
TEFLON BATH: PTFE is applied to the entire structure of the fabric encapsulating each individual fiber to improve chemical resistance and dust release.
FELT FABRIC TYPES
ARAMID: Known as Nomex® or Conex®, aramid has fair resistance to both acids and alkalis, has excellent abrasion resistance and a maximum operating temperature of 375º F.
HOMOPOLYMER ACRYLIC: Known as Acrylic or Orlon®, has excellent resistance to acids, good resistance to alkalis, fair abrasion resistance and a maximum operating temperature of 260º F.
EPITROPIC: Carbon fibers blended in the polyester needlefelt. Used to reduce possibility of static dissipation.
FIBERGLASS: Usually used in high heat applications. Continuous operating temperature of 450º F.
MICRO DENIER: Scrim supported product. Has a larger denier product with a cap of a fine denier fiber. Beneficial for fine particle filtration.
P84: Irregular fiber shape that provides more surface area, P-84 fabric achieves higher filtration efficiencies than other similar denier fibers. It has good resistance to acids, fair resistance to alkalis, good abrasion resistance and a maximum operating temperature of 460º F.
POLYSESTER: Known as Dacron®, polyester fabric is the most commonly used fabric for dust collector bags. It provides an economical combination of good resistance to both acids and alkalis, has excellent abrasion resistance and a maximum operating temperature of 275º F.
POLYPROPYLENE: Known as Herculon®, polypropylene has excellent resistance to both acids and alkalis. Has good abrasion resistance and a maximum operating temperature of 180º F. Micro-denier fiber is not available.
PPS: Known as Ryton®, Torcon®, or Procon®, PPS has excellent resistance to acids, good resistance to alkalis, good abrasion resistance and a maximum operating temperature of 375º F.
PTFE: Known as Teflon®, PTFE has excellent resistance to both acids and alkalis, poor abrasion resistance, and has a maximum operating temperature of 500º F. Micro-denier fiber is not available
