GLOSSARY
How to identify Mesh: Mesh Count – How to calculate the open Area
| Term | Description |
| Absolute Filter Rating | Filter rating at 99% efficiency |
| Nominal Filter Rating | Filter rating at 70-90% efficiency |
| Aperture | Distance between wire threads, measured in microns or millimeters |
| Pitch | Distance from centre to centre of wire threads |
| SWG | Standard Wire Gauge (Imperial Measurement) |
| Imperial Mesh | Number of apertures counted in a row, see mesh count above |
| Weft | Wire threads running down the width of the roll |
| Warp | Wire threads running down the length of the roll |
| Micron | 1/1000 of a millimetre |
| Open Area | Percentage of free area in mesh or metal, see illiustration above |
| Blinding | Blockage or restriction of the apertures of a sieve or filter by particles |
| Differential pressure | Pressure ratio upstream and downstream from the filter |
| Dry screening | Screening powdered materials without liquid |
| Mesh analysis | Separation of a bulk material sample and analysis of particle size |
| Mesh counter | Optical device used to establish mesh count |
| Mesh fineness | Number of wires per inch (Imperial measure) |
| Mesh thickness | Calculated according to wire diameter and mesh type |
| Service life | Operational life of a screen/mesh until it requires replacement |
| Square weave mesh | Mesh woven with wires spaced at a distance, giving open apertures |
| Twilled weave | Mesh type giving small filter pores |
