New developments in surface layer filtration

Shanghai Hongli Purification Technology Co., Ltd. adds that the filter mechanism bridges pore openings and has been developed by the company over the past ten years.The company maintains that the new method avoids all inherent shortcomings and yet retains all inherent advantages from both surface and depth filtration. Its major features include: good precision and filtering efficiency; low power consumption; high efficiency of washing and dewatering for cake, low consumption of washing liquid; long service life of media; quick and efficient dry cake discharge; automated operation; and is environment friendly.The company adds that a total of 1128 units of surface layer filters for filtering, washing and dewatering of ultra-fine powder with different filter areas have been successfully deployed in 528 factories. Applications since 2004 have included the filtration for ultra-fine catalysts (for example, palladium carbon or copper nickel catalysts), ultra-fine powder activated carbon, ultra-fine metals or metal compounds, and ultra-fine absorbents.Shanghai Hongli Purification Technology Co adds that other developments include:• Large area filtering plates of 1.8×1.8m possessing resistance to back-blown air pressure of 1MPa.• The surface layer filters have large filter areas with two or three levels of media within a confined unit space, resulting in a significant increase in filtration capacity.• Agitated or fluidised washing of gas-liquid-solid phases, giving rapid dewatering of cake by low pressure gas and quick and automatic discharge of dry cake.According to the company, the main technical indicators include:• A filtration efficiency of over 99.9% for 0.2μm powder particles through one filtration cycle.• Low power consumption of filtration, washing and dewatering. The pressure difference in all operations is below 0.2-0.25 MPa and the mean power consumption per cubic metre of filtrate is less than 0.20.25 KWh.• Washing liquid consumption per tonne of ultra-fine powder is less than 10m3.• The service life of the media is over one year.• Filtration area per square metre of land area of filters is over 20m2.