Different classification standards for filter media for bag filter

There are many types of filter materials for bag filters. Bag filters are currently widely used in China. Different technologies and methods will use different filter materials for filtration. The filter materials of manufacturers on the market can be roughly classified according to the following methods: 　　　　一, According to the material classification of the filter bag: 　 　 1. Synthetic fiber filter material: a filter material manufactured with synthetic fiber as raw material, referred to as synthetic fiber filter material.　　2. Glass fiber filter material: a filter material made from glass fiber, referred to as glass fiber filter material.　　3. Composite filter material: a filter material composed of two or more fibers.　　4. Other material filter materials: filter materials made of fiber materials other than synthetic fibers and glass fibers (such as ceramic fibers, metal fibers, carbon fibers, mineral rock fibers, etc.).　　　　Second, according to the structure of 　　 according to the structure of the filter material can be divided into woven cloth, needle felt, surface filter material, etc.　　(1) Woven fabric 　　 Woven fabric is a fabric made by continuously interlacing warp yarns and weft yarns at right angles according to certain rules. Its basic structure has three types: plain weave, twill weave and satin weave. In order to improve the performance of the woven filter material, the weft double or double layer structure is often used.　　Machine woven fabric has been the only selectable filter structure for a long time. The emergence of needle felt made it gradually relegated to a secondary position.　　(2) Needle-punched felt 　　Needle-punched felt is a filter material made by spreading fibers on the bottom 2 sides, or completely using fibers to form by needle punching, and then undergoing post-processing. It does not undergo the weaving process, so it is also called non-woven fabric or non-woven fabric.　　 Needle-punched filter media post-treatment mainly includes heat setting, singeing, hot melt calendering, etc., and some treatment processes such as antistatic, hydrophobic, acid and alkali resistance, oil repellency, and resin covering. The pores of the needle felt are formed between single fibers, so there are multiple pores in the thickness direction, the porosity can reach 70-80, and the pores are uniform. In contrast, the pores of woven fabrics are formed between the yarns, there are no layers in the thickness direction, the porosity is 30-40, and there is about half of the needle felt. Therefore, at the same filtering speed, the pressure loss of needle felt is lower than that of woven fabric, and the dust removal efficiency of needle felt is also higher than that of woven fabric.　　(3) Surface filter material 　　Surface filter material refers to a filter material in which almost all dust, including fine dust particles, remains on its surface and cannot penetrate its interior.　　 Based on the theory that the dust layer is beneficial to filtration, a layer of microporous film is artificially attached to the surface of the ordinary filter material to improve the efficiency of dust removal. Therefore, the film on the filter surface is also called the artificial dust layer. The advantage is that a thin layer of dust with good air permeability can be formed on the surface of the membrane at the beginning of the filter work, which can ensure high dust removal efficiency and low running resistance.