| 摘要 |
A filtration medium is produced under conditions of heat and pressure such that it has a density in the range 450 to 950 kg/m<3>, a pressure drop in the range 75 to 1250 Pa at an air velocity of 1.6 m/min (as measured by a BS4400 test), and a gauge in the range 0.7 to 1.25 mm. Any suitable thermoplastic fibre may be used, e.g. polyester fibres alone, a blend of polyester and polypropylene fibres, a blend of polyester and bi-component fibres, polyimide fibres and polyphenyl sulphide fibres. Filter units made from such filtration media may be of the flat bag type or a multi-pocketed corrugated element or of any other desired configuration. |
