Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solids from liquids or air.
Properties
Filter paper comes in various porosities and grades depending on the applications it is meant for. The important parameters are porosity, particle retention, flow rate, strength, compatibility, efficiency and capacity. There are two mechanisms of filtration with paper; volume and surface. By volume filtration the particles are caught in the bulk of the filter paper. By surface filtration the particles are caught on the paper surface.
Manufacture
Main article: Paper machine
The raw materials are different paper pulps. The pulp may be from softwood, hardwood, fiber crops, mineral fibers. For high quality filters is dissolving pulp used. Most filter papers are made on small paper machines. For laboratory filters the machines may be as small as 50 cm width. The paper is often cred to improve porosity. The filter papers may also be treated with reagents or impregnation to get the right properties.
Types
Wire Cloth Strainers
Basket Filter
Wire Mesh Filter
Panel Filter
Diesel Oil Filter
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