A plain fabric is unfinished. In many cases a filter fabric is treated (finished) so that it can withstand various conditions such as moisture or abrasion. Many of the treatments are mechanical surface treatments and others are chemical treatments of either the entire fabric or just the fabric surface.
Mechanical surface treatments generally improve the dust cake formation on the filter and filter cleaning. Common treatments include singed, glazed, calandar and membrane. The first two smooth the surface of the needled felt to improve dust cake formation and filter cleaning.
|SINGED||Running the fabric over an open flame to remove high points and fiber fuzz.|
|GLAZED||Like a singed treatment but more pressure applied to produce a smooth surface.|
|CALANDAR||Compressing a needled felt between rollers, which improves the felt density.|
|COATED||Proprietary smooth not fibrous, micro permeable coating with excellent dust cake release and improved resistance to blinding.|
|MEMBRANE||Laminating and expanded layer of polytetrafluoroethylene (PTFE) to needled felts, which makes it easier to clean sticky or very fine dust from the fabric and reduces the required cleaning frequency.|
|ARAMID||High temperature felt, which operates continuously up to 375° F (surges up to 425° F). It has a high tensile strength and excellent abrasion resistance.|
|PPS||PPS (polyphenylene sulfide) is a high temperature felt. PPS operates continuously up to 375° F (surges up to 425° F) with the same properties as aramid with the additional benefit of excellent acid and alkali resistance.|
|P-84®||High temperature felt operating up to 500°F (surging up to 550°F) and exhibits excellent abrasion resistance and good acid resistance. This is very efficient felt, due to the irregular shape of the fibers, giving them greater surface area.|