TABLE OF CONTENTS Liquid filtration applications are concerned with the filtration of either aqueous or hydrocarbon fluids. A large use of liquid filter media made from nonwovens and filter paper is in engine filtration applications. Engine filtration to include both air and liquid filtration is treated as a separate subject in Chapter 9.
The types of nonwovens used in nonautomorive liquid filter applications include needlefelts, paper sheets, filter papers, resin bonded paper, dry laid webs, and spunbond products. In liquid filtration there are also important applications for nonwoven supported membrane filters.
Large scale liquid filtration is accomplished mostly by cake filtration. Many forms of filter equipment use a filter fabric to support the cake. Often, the fabric is a woven filter cloth; however there are applications where the fabric is a needlefelt nonwoven. In recent years there has been an emergence of Spunlace (hydroentangled) felts and fabrics for industrial filter applications. Nonwoven and paper filter media are popular in filter presses.
Replaceable filter elements are used in many filter applications. Two of the most common types are liquid bag filters and cartridge filters. Liquid bag filters are often made of woven fabric filter media; however there are some applications where a nonwoven or a nonwoven composite material is utilized. A well-known form of a bag filter is the teabag composed of wet lay Manila hemp (abaca) fibers.
The biggest use of nonwovens in liquid filtration is as cartridge filters. Cartridge filters are used as polishing filters in...
