Glossary

A measure of retention, expressed in microns, that specifies the equivalent diameter of the smallest particle from which the filter has retention of 100%. In actual practice, most manufacturers assign absolute ratings on the basis of retention in the range from 98% - 99.999999%.

Bolting Cloth – A thin, strong, flexible precisely woven group of meshes which are used for sieving and sifting powders. 

Coarse Stainless Steel Mesh - Openings that range from about the size of a pencil lead (1/16 inch) and downward to the size of a medium human hair (1/125 inch).

Fine Stainless Steel Mesh - Group of stainless steel wire cloth mesh has openings that range from about the size of a medium human hair (200 microns) and downward  to the size of a large bacteria (2 microns).

The size of wire.

A linear foot is a unit of measurement of length. A piece of material measuring, for example, 3 feet wide by 15 feet long would be 15 linear feet. The same piece of material could be described as 45 square feet; 3 feet wide X 15 linear feet which equals 45 square feet. Note: sometimes the term "running foot is used to mean linear foot".

The number of openings in a linear inch, measured from the center of one wire to a point one inch distant. Also known as “Mesh Count”.

The hole size which is the distance between two adjacent parallel wires.

A unit length in the metric system. One micron is equivalent to .00003937 of one inch.

A measure of retention, expressed in microns, that specifies the equivalent diameter of the smallest particle for which the filter has a retention somewhere in the range of 60-90%. Nominal filter rating is imprecise.

Plain Dutch Weave (PDW) – A plain weave with the warp wire of a larger diameter than of the shute wire. The weave is made up of a limited number of warp wires interwoven with the maximum number of shute wires which can be positioned. The cloth is strong and firm and is most frequently used for high pressure filtration.

The most commonly used weave. Each shute wire passes alternatively over and under each warp wire and vice versa. Warp and shute wire diameters are generally the same.

The wires running across the width of the cloth as woven (short wires).

Soffit Screen – Galvanized Hardware Cloth used for vent screening.

Spark Arrester - Steel mesh that stops sparks and allows light and heat to pass through.

A square foot is a unit of measurement of area. A piece of material measuring 12 inches by 12 inches is one square foot. To compute the number of square feet in a piece of wire mesh you multiply its width in feet times its length in feet. For example, a piece of wire mesh 4 feet wide and 3 feet long would be 12 square feet.

Stronger than plain weave. Each shute wire alternatively crosses over two, then under two warp wires, producing a diagonal pattern. The wire diameter for both warp and shute is normally the same. Twill weave can be used to accommodate a heavier than standard wire diameter in association with a given mesh. Specifications finer than 300 are normally twill weave.

Twilled Dutch Weave (TDW) – Similar to plain dutch weave, except that the weave pattern is twill, i.e. a double layer of shute wires. There are no openings in the true sense of the word, and the filtrate follows a tortuous path through the triangular passages in the mesh. Twilled Dutch Weave  is a surface filtration medium, often used under high pressure.

The wires running the long way of the material as woven (long wires).