Vacuum sewerage system having non-jamming vacuum valves with tapered

Abstract

An improved vacuum sewerage system for transmitting sewage, including at opposite ends a sewage collection tank at atmospheric pressure and a vacuum collection tank under vacuum pressure. The sewage is intermittently injected into a transport conduit under vacuum or subatmospheric pressure when a non-jamming vacuum control valve interposed in the conduit is opened in response to a predetermined pressure condition. The 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 collects in the low point, which generally does not completely fill with sewage so that vacuum or subatmospheric pressure is communicated throughout the conduit. When the control valve is opened, the sewage transported through the conduit forms a generally hollow cylindrical mass, which is propelled toward the vacuum collection tank. The control valve has a substantially tapered, rigid plunger, and will not jam in the open or semi-open position as a result of repetitive cycling of the valve by an associated control unit. The plunger is mounted at one end of an axially disposed shaft of a piston operator in the valve chamber, and the valve is sealed to prevent leakage of air or liquids. The non-jamming valve is capable of facilitating a flow rate of thirty gallons per minute. The combined vacuum valve and vacuum transport system may be used to convey other types of collected waste liquid, such as used cutting oils.