The filter uses the porcelain sand and ceramic grain as the filter medium instead of the traditional quartz sand and blind coal.
　　The filtered water flowing direction is from the bottom coarse grain to the top fine filtering section, in other word,“the coarse reflux grain” process, The process has a excellent advantage, compared to the traditional plus filtering, that is the real “high efficient filtering”. The filter advantage is as following:
　　A.The outlet water quality is good. When the inlet turbidity is 15~20, the outlet even turbidity is bellow to 1 on one period.
　　B.The filtering velocity is high. When the inlet turbidity is 15~20, the even filtering velocity is up to 16~20m3/m2h (recommended volume).
　　C.The filtering pressure head is low, It is only 1m, 1/2 of the traditional one (saving of electricity 2/3).
　　D.The filtering period is long. The period is 24 hours, when the inlet turbidity is 10. This is more then 2 times of the traditional period 8 hours.
　　E.The filter is made of the selected unique porcelain sand and ceramic grain on the special processing. The filter has much advantage, such as corrosion-proof、 anti-oxygenation、avirulence、high strength、long life(up to 15~18years) 、large specific area of the spherical particle、point-connecting each other、high avoid volume、strong pollutant entrapment capacity、good effect、long water flowing distance on the working state. This feature makes it uncomparative with others, It is the most valuable filtering material to enlarge the capacity, ensure for a long working time and save the running cost. "The coarse reflux grain filtering technology" can also be used in the filtering pond, addition to the filter.