Filter cloth is the most widely used filter medium in industry. Filter cloth can be divided into textile filter cloth and non-woven filter cloth. The composition data are natural fibers (cotton, wool, silk, hemp) or synthetic fibers. The filtration function of filter cloth depends on raw materials, fiber weaving and post-treatment.
- According to the material properties, filter cloth can be divided into polyester, polypropylene, nylon, vinylon, all cotton, new high-efficiency materials and other filter cloth.
- It can be divided into two types according to the way of textile.
Textile filter cloth: including polyester, polypropylene, nylon, vinylon, cotton, etc. There are several weaving methods of filter cloth, plain, twill, satin, double-layer weaving, etc.
Non textile filter cloth: including non-woven cloth, geotextile, filter felt, etc. The methods include spunbonded, needling, water weaving, etc.
- The silk material of filter cloth is also divided into three types: monofilament, long fiber, multifilament and short fiber. (The polyester staple fiber series is also divided into large chemical fiber and small chemical fiber)
Nonwoven filter cloth is the lightest and easy to handle polypropylene fiber among synthetic fibers, with excellent temperature resistance of 90 ℃ and acid and alkali resistance.
Therefore, it is used in the field of gas-solid and liquid-solid separation with flue gas temperature below 100 ℃ or strong acidity and alkalinity In the field of liquid-solid separation, polypropylene needle punched filter felt is usually equipped with plate and frame filter press, vacuum suction filter, belt filter, centrifugal filter and other liquid-solid separation equipment It not only has the characteristics of good dimensional stability, high strength and small elongation, but also has flat and smooth surface, pores and high permeability. Therefore, it also has the unique advantages of low vacuum resistance, energy saving and easy cleaning In mineral processing, coal preparation, petroleum, chemical industry and other industries, where it is necessary to filter small particles and ensure filtration, polypropylene needle punched felt has far superior performance than traditional woven filter materials Polypropylene needle punched filter felt is generally made of 2.5-6d polypropylene short fiber as the surface layer, lined with base cloth woven of polypropylene yarn or polypropylene high-strength silk in the middle, and processed by post-treatment processes such as needle punching reinforcement and calendering Polypropylene needle punched filter felt is mainly used in the field of liquid-solid separation in metallurgy, mining, petroleum, chemical industry, chemical fiber, medicine, food and other industries
Filter media woven from natural or synthetic fibers. Commonly used materials include cotton, hemp, wool, cocoon silk, asbestos fiber, glass fiber and some synthetic fibers. For example, cotton canvas, twill and wool, etc. Broadly speaking, filter cloth also includes metal mesh or filter screen.
Synthetic fibers mainly include polypropylene, polyester, nylon and vinylon, among which polyester and polypropylene are most commonly used, mainly for solid-liquid separation, while nylon is widely used in coal washing plants because of its excellent wear resistance.
The new high-efficiency filter cloth is mainly used for air filtration, dust removal and dust collection to purify the air and protect the environment. It is widely used in smelters, chemical plants, sugar making, dyes, medicine, food and other industries.
Filter cloth and screen made of polyester, polypropylene, nylon, vinylon and cotton are widely used in pharmaceutical, chemical, dye, steel, construction, iron governance, chemical, ceramic, cement, geology, mineral and other industries.
When the filter cloth is used as the filter medium of the centrifuge, the drum is equipped with a metal lining net, and the filter cloth is laid on the lining net and fixed. Because the filter cloth is soft and has low strength, the mesh of the lining mesh should be smaller, so as to effectively support the filter cloth and discharge the filtrate smoothly. The filter cloth is required to have satisfactory strength, suitable pore size and porosity, corrosion resistance and wear resistance to the treated materials. There are three weaving methods of filter cloth, plain, twill and satin. The weaving method of plain is the most rigorous, followed by twill, satin is sparse, and the porosity increases in turn.
Note: “mesh” refers to the number of holes on the screen per square inch (1 inch 25.4mm), 50 mesh refers to 50 holes per square inch, and 500 mesh refers to 500 holes. The higher the mesh, the more holes; In addition to indicating the holes of the screen, it is used to indicate the particle size of the particles that can pass through the screen. The higher the mesh number, the smaller the particle size.