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Structure and classification of filters: classification: 1 by speed size: slow filters, fast filters, high speed filters; 2 by direction of current filters: upward, downstream, two-way; 3 by type of filters: sand filters, coal filters, coal-sand filters; 4 by number of filters: single layer, double layer filters, multilayer filters; 5 by nature of water: pressure filters and gravity filters; 6 by means of supply and discharge: general fast filters, rainbow filters and valve-free filters. Structure: the outside of the filter pool consists of pipes and accessories, such as filtration pool bodies, water entry pipes, water discharge pipes, wash drains, etc.; the interior of the filter pool consists of rinsing discharge tanks, entry canals, filter layer, gasket layer (carrying layer), drainage system. The ordinary fast-filtration pool process: the filter-repeated two processes alternate. When water is filtered into the filtering pool, the effluent is fed into the canal, the draining sink is distributed into the filtering pool, and the wastewater is fed from the top down through the filtering layer, the gasket layer, collected by the drainage system and discharged from the draining tube. The filter is fully immersed during the work. When flushing, the pipe is closed, the drain valve is opened and the drain is washed into the pipe, and the reverse wash is washed down through the drainage system, the mat, the filter layer, which is collected by the drain tank and removed through the draining pipe inside the canal. The requirements for filters and the structure of the filters: the requirements for filters: 1. The filters are larger in size, more physical strength, more corrosive and less costly; and 2 are more resilient to shocks。
