Filter is the use of one or several filter media, under a certain pressure to the turbidity of water through a certain thickness of the granular or non-granular material, which effectively remove suspended impurities to clarify the process of water, commonly used filter There are quartz sand, anthracite, manganese sand, mainly used for water treatment in addition to turbid, softened water, pure water pre-treatment, the water turbidity of up to 3 degrees below.
The filter media is high quality homogeneous gravel, quartz sand, magnetite, anthracite and other media, the filter according to their specific gravity and size of the size of the filter tank in the scientific and orderly distribution, such as the proportion of small While the larger size anthracite on the top of the filter bed, the proportion of moderate and small size of the quartz sand on the middle of the filter bed, than the major and large particle size of the gravel on the bottom of the filter bed. This ratio ensures that the filter in the backwash when the phenomenon does not produce chaos layer, thus ensuring the ability of the filter material retention.