LOW-RATE SAND FILTER FOR USE IN CONDITIONS OF INTERMITTENT SUPPLY OF A WATER STREAM AND A METHOD OF ITS APPLICATION Russian patent published in 2004 - IPC

FIELD: low-rate sand filter for intermittent supply of water. SUBSTANCE: the invention presents a low-rate sand filter for use in conditions of intermittent supply of water stream and a method of its application. The low-rate sand filter includes: a container having an upper part and a lower part; a water inlet tool located in the upper part of the container and linked with a water source; a filtering material, which fills at least the lower part of the container and the top surface of which is located below the water- inlet tool; the biological layer located on the top surface of the filtering material; the water outlet tool located in the lower part of the container below of the top surface of the filtering material; the device of maintaining the water level located in the upper part of the container, which maintains the water level in the upper part of the container, so that a water layer located above the biological layer is thick enough to prevent a considerable shaking of the biological layer located on a top surface of the filtering layer and at the same time to be sufficiently thing for diffusive infiltration into it of oxygen from the space above the water with the oxygen following reaching the biological layer and so to keeping the biological layer alive even in absence of supply of water from the water-inlet tool; a dispersing lattice located above the water level, a cleaning mechanism, a maintenance mechanism. EFFECT: high effectiveness of filtration of water at operation with time breaks and periodic purification of water without malfunctions. 17 cl, 22 dwg