There are many ultra filtration products in current market with similar structures, which most adopt hollow fiber membranes. Flat UF membranes are rarely used. A variety of materials are used for UF membrane, such as polysulfone, polypropylene, PVDF, nylon, polyacrylonitrile. Polypropylene is low resistant to high-temperature and chlorine, nylon has poor chlorine resistance and polyacrylonitrile easily hydrolyzes after staying in water for a long time. Polysulfone features high inertia to chemical substances, and only has weak reaction with sulphuric acid. Polysulfone materials top in high temperature resistance, second only to polytef. Polysulfone can be made into medical instrument, thanks to its high intensity and safety. Membranes made from it can stand water hammer and multiple washes, no worry for secondary pollution. 

When talking about concerns of water purifiers, the emission of concentrated water pops up on the mind. However, with technological innovations, recycle rate of RO purifier can be lifted substantially and the usage of water can be saved. Side stream RO membrane components are researched and patented by A. O. Smith (Nanjing) Water Treatment Products Co., Ltd. These include multi-page repetitive folding technique for higher service efficiency, enlarging membrane area for higher water productivity, changing the membrane structural for the direction of water flow, diminishing the water flow channel for enlarging water flow rate, using rhombus-shaped mesh with big voidage for increasing the Reynolds number, so the deposit sediment reduce that the membrane working life increases by 30%, thereby, reducing the working life of pretreatment filter for cost reduction. The patented technology, first in the industry, can accommodate a wide range of water qualities and has received favorable responses after hitting on market. 

MLSB is an acronym for “Multi Leaves Single Bag”. Traditional RO membrane is composed of multiple folding membranes. Effective area of each membrane components are reduced inevitably due to two gluing lines sealed. The shorter the membrane, the bigger proportion the glue line of fixed width takes. By increasing the utilization rate of the same size membranes, the water productivity is up 10-15% and the usage rate of membrane sheet is up 85-90%. The rate was 70% under traditional techniques. Thanks to the improvement, the total size and efficiency of water filter are improved.