Multi-layer air filter

摘要

Multi-layer filter material for purifying dust-laden air comprises at least two different fibrous materials arranged in alternating layers. The fibre dia. of one material is 25-35 mu m, the thickness of the layers of that material not exceeding 2 1/2 mm. Fibres consists eg. of polyester. The fibres hold larger amounts of dust so that the filter service life is increased.