Woven wire cloth is widely used for filtration and is available in a wide range of materials and mesh sizes. It can be woven from any material which is ductile enough to be drawn into a wire form. Preferred materials are phosphor bronze, stainless steel and monel (nickel alloy). Other materials widely used include aluminium alloys, copper plain mild steel or coated mild steel.
The minimum particle size of wire which can be used depends on the alloy, strength required, temperature and corrosion.
For figuring out mesh sizes you have to count the number of openings from the center of any one wire to the center of a parallel wire one inch away. The number of openings is the mesh size. So a 2 mesh screen means there are two little squares across one linear inch of screen. A 100 mesh screen has 100 openings, and so on. Note, therefore that as the number describing the mesh size increases, the size of the particles decreases. Screens can be made with different thicknesses of wire. The thicker the wires, the smaller is the particle passing through that screen, and vice versa.
This formula can be used to calculate the space between the wires:
When working with these formulas you should be careful with the inch units. There is a difference between the English inch of 25.4 millimetres and the metric inch of 27.07 mm, whereby the latter is used very seldom.
The aperture opening expresses the open area of the cloth. Wire Mesh contains open spaces (holes) and material. Open area is the total area of the holes divided by the total area of the cloth and is expressed as a percent. In other words, open area describes how much of the wire mesh is open space. This parameter can be calculated by means of the mesh number and the thickness of wire (D). With these two information is it possible to obtain the space between the wires and the open area for every existing mesh number.
For an easier handling it is possible to use the following table, which provides the aperture opening and also the relation between space between wires and thickness of wire for every mesh number.
|I.S.W.G||Size in inches||Size in mm|| |
Thickness of wire, diameter in mm