17 DEC 2003
5-3.2.1 Type of Media. The types of media used to manufacture cartridge filters in-
clude cotton, nylon, polypropylene, polyester, acetate, acrylic, glass, polyethylene, mo-
dacrylic, rayon, saran, and fluorocarbons. Ceramics and metals may also be used in
non-disposable filters. In addition to the various types of filter media, filters are con-
structed of woven fabrics, felts, and non-woven fibers, porous solids, and polymeric
membranes. The media and media construction are selected according to waste stream
characteristics, filter operating conditions, and desired effluent quality. Summarized be-
low are some general information and uses for media material and construction type.
5-188.8.131.52 Fabrics of Woven Fibers. There are four basic types of weave used as the
base material for filters: plain or square weave, twill, chain weave, and satin. All the
weaves can be made from textile fiber of natural or synthetic origin. Generally, the
smoother the filter fabric is, the tighter the weave and the smaller the pore openings.
Filter fabric made from larger diameter fibers will offer greater strength than fiber made
from finer fibers of the same material. However, the greater the fiber diameter, the
looser the weave, and the larger the spore spacing.
5-184.108.40.206 Metal Fabrics or Screens. Filters made of metals are available in a variety of
weaves and types of metal, including nickel, copper, brass, bronze, aluminum, steel,
stainless steel, and other alloys. Good corrosion and high temperature resistance of
properly selected metals make metal media desirable for long-life uses, particularly
since they can be cleaned. Metals are also suitable for applications involving high differ-
ential pressures and vibration or shock conditions.
5-220.127.116.11 Pressed Felts and Cotton Battings. Felts and cotton battings are non-
woven fabrics made from natural fibers. These materials usually operate as filters by
deposition of the particles on and throughout the weave. They are often used to filter
deformable materials such as gelatinous particles from paint.
5-18.104.22.168 Non-woven Fabrics. These filters are made of synthetic fibers such as
polyester and nylon and are lighter than felts. They are used to filter highly viscous flu-
ids to remove particles as small as 5 microns. They are often configured as string
wound or other depth filtration type cartridges.
5-22.214.171.124 Filter Papers. Filter papers are available in a wide range of permeability,
thickness, and strength. They generally require a perforated back-up plate for support.
5-126.96.36.199 Rigid Porous Media. These media are available in a wide range of materials,
including stainless steel, ceramics, and some plastics. They are ideally suited for waste
streams that require a wide range of chemical and temperature resistance.
5-188.8.131.52 Combinations of Media. Because some filters are composed of several me-
dia types, it is important to make sure that each filter medium is compatible with the
particular waste stream. Tables 5-6 and 5-7 summarize the types of filter media and
compatibility with generic waste streams. Table 5-7 gives a broader discussion on mate-