Method of cleaning the filter medium of a gravity sand filter and a filter system

摘要

The invention deals with a method of cleaning the filter medium of a gravity sand filter and a filter system. Therein the filter medium is placed on the divider, under which compressed air is brought, permeating through openings in the divider to the filter medium and on the way to its surface releasing turbidity to the water layer above the filter medium, when subsequently turbidity and water are drawn off. Compressed air brought under the divider pushes filtered water out of the space under the divider to the filtered water tank, while the volume of incoming compressed air per unit of time is larger than the volume of outflowing water pushed to the filtered water tank.