Types of filters. Filtration, despite rapid development of science and technology, is still an important part of industrial fluid purification. A filter predominantly separates solids and water. Filtration is a common process, applied alone or in combination with other approaches. It all depends on the purity requirements and the initial composition of contaminants.
The effectiveness of filtration is greatly influenced by filter material. In this article we will discuss the most common filter materials.
Metal wire mesh varies in structure, method of manufacturing and configuration. According to the method of manufacturing there are woven, welded, twisted, braided stainless steel mesh filters. Mesh holes configurations are rectangular, rhombic, square etc. The wire used in filters is made of bronze, stainless steel, brass, nickel and other materials.
Non-metal mesh is made of synthetic polymers such as polypropylene, lavsan, capron, nylon, etc. The structure of non-metallic filters is similar to the structure of metallic filters. Their advantage is high corrosion resistance. The filtration fineness is 10 microns, with the possibility of increasing that to tenths of a micron.
Filter fabric is frequently used for purification of fluids. The most widely used fabrics are cotton, wool, silk, flax, asbestos, etc.
Textile filter materials made from natural and synthetic fibers, and mixtures thereof. The main advantage of these materials compared to natural fabrics is the lower cost and better filtration capacity.
Paper and paperboard is used for filtration of aggressive liquids such as petroleum products. The filter paper is made out of wood pulp or cotton fibers.
Membrane filter media is produced from cellulose nitrate and acetate, polyamide, polyvinyl chloride, and fluorocarbon etc. To increase the mechanical strength, the material is reinforced with ultra thin wire or synthetic fabrics (teflon, nylon etc.).
Sintered metal-powder materials are made from sintered metal powders of bronze, aluminum, stainless steel, tungsten
Ceramic materials are produced from sintering of granular mineral particles with added binder (optional).
Polymer filtration materials are porous plastics. They are economical due to the low cost of production. Among the disadvantages of foam materials is their uneven pore structure (it is difficult to ensure stable pore size).