Polytetrafluoroethylene (PTFE) film has a smooth surface and chemical resistance, which is coated on the surface of ordinary filter materials, playing a role of disposable dust layer, which can intercept all dust on the surface of the membrane and achieve surface filtration. Moreover, because of its smooth surface, excellent chemical stability, non-ageing and hydrophobicity, the dust intercepted on the surface is easy to peel off and improve. The service life of the filter material is improved. Compared with ordinary filter media, it has the following advantages: - The pore size of the film ranges from 0.2 to 0.3 um, and the filtration efficiency can reach 99.99%, almost achieving zero emission. The efficiency of dust removal is always high without changing the porosity after dust removal. - The pressure loss of the membrane-covered filter material is higher than that of the ordinary filter material at the beginning of its use, but the pressure loss does not change much with the increase of the use time after it is put into operation, while the pressure loss of the ordinary filter material will increase with the prolongation of the use time. - In the use of ordinary filter materials, dust can easily enter the interior, and accumulate more and more, until the pore is blocked, leading to the failure to continue to use. Using PTFE membrane filter material, the filtered dust can be easily removed from the surface of the membrane. The effect of cleaning dust is good, the cycle is long, and the pressure intensity of cleaning dust used is low, thus improving the service life of the filter material and reducing the operation cost of the product. INDRO filtration(Shanghai Filterworkshop) chooses high quality PTFE microporous membrane in China and out of China, which is coated with woven filter material and needle punched non-woven filter material to make PTFE membrane filter material. It is widely used in the fields of flue gas purification and dust removal, dust control and material recovery.