Vacuum sewerage system with increased lift capabilities having electric

Abstract

An improved vacuum sewerage system for transmitting sewage through an intermittently opened sewage control valve of a transport conduit by means of differential pressure. The vacuum conduit is laid out in a saw-toothed fashion, having a riser, a low point, and a downslope. When no sewage is being transported through the conduit, any residual sewage in the conduit collects in the low point, with minimal intermittent closure of the conduit over time to permit minimal drop in vacuum or subatmospheric pressure throughout the conduit such that there is more than adequate vacuum or subatmospheric pressure available to operate the control valve. When the control valve is opened, the sewage transported through the vacuum conduit forms a generally hollow cylindrical mass, which is propelled toward a vacuum collection tank. The system includes an electric air admission controller ('EAAC'), which automatically opens and closes an air control valve independently of the level of accumulated sewage upstream of the sewage control valve, in order to inject additional air at atmospheric pressure into the vacuum transport lines to apply additional fluid pressure to a mass of sewage therein, and to avoid a waterlogged condition by supplementary transport. A conduit line having more than 13 feet of total lift is thereby possible, provided that the sum of the pressure losses across all the risers equals or exceeds the sum of the minimum subatmospheric pressure condition available at the vacuum collection station minus the pressure head required to operate the control valve.