| 摘要 |
Liquids and especially water are purified by filtration. Floating and/or colloid particles are removed from water by several layers of filter granules. Each layer is distinguishable from any other by its characteristic pore volume. Filtrate is removed from the filter tank, and the at least partially clogged filter charge is regenerated by washing with streams of fluid/water. Residual, sludge containing rinses are removed from the tank. Pore volumes of layers forming the charge are decreasing in the direction of fluid flow. The smallest particles sized and pore volume containing layer is in a separate (inner) compartment of the filter tank. There are no further layers above this one, and the compartment contains a regeneration space instead. The direction of flow of liquids passing the coarser porosity layers is reversed when partially filtered liquids enter the finest layer in opposition of the direction of main flow). Regeneration of the filter charge is carried out by rinsing with water/liquid at such a rate, that during rinsing the volume of the finest layers of the main charge should not expand by more than 40%. The separate finest pore size layer is subjected to a counter-current rinse (i.e. when filtration flow direction is reversed). The rate of this flow agitates the layer loosening it, to reach a fluidized state in the regenerating space. When the flow of rinsing ceases, the granules of layer are allowed to settle and its original state is restored. The filter tank has a base area. This base area holds the charge of filter layers the pore volumes of which decrease in the direction of flow. The filter tank has facilities for feeding in liquids to be filtered, for removal of filtrates and of slurry containing post regeneration rinsing media. The essence of this installation is that the smallest pore-volume layer separated from the main filter-layer charge, by having its own regenerating compartment, complete with its own filter base. The regenerating compartment volume is sufficient to hold layer in fluidized state. Filter layer is so arranged, that the direction of liquid flow leaving the bulk of the filter charge, is altered and/or, that there are facilities in the filter tank for altering the direction of flow used during filtration. |
