Multi-cell gravity filter with central control chamber

Abstract

A multiple filter, gravity flow, liquid filtering apparatus includes a plurality of adjacent independent filter chambers with common influent and effluent passages surrounding a centrally located effluent control chamber and having provisions for backwashing at least one filter chamber with the effluent from companion filter chambers. The effluent control chamber preferably has two sections, a lower section which serves to collect filtrate from each of the surrounding filter chambers through a plurality of flow transfer ports which communicate with each filter chamber, and an upper section which houses equipment and controls for filtering and backwash operations. In one embodiment, the lower section includes a vertically disposed outlet conduit with an adjustable weir located at the open end of the conduit. The weir is used to adjust the liquid level in the lower section of the control chamber to control filtering and backwash operations. In a second embodiment, the effluent control chamber includes a specially designed pumped backwashing system in lieu of the adjustable outlet weir. The pump assembly is mounted on the floor of the upper section with associated flow distribution valves and pipes located in the lower section and communicating with the respective flow transfer ports of each filter chamber. The pumped backwashing system is designed to pump flows in the control chamber to individual filter chambers during a backwash event.