Abstract: A Pump consisting of a pressure vessel (50), an inlet nozzle (51), an ejector nozzle (52) by which vacuum and pressur are applied, and an outlet nozzle (53). The inlet and outlet nozzles (51, 52) are selectively closed by interconnected knife gate valves, operated in tandem by a pneumatic cylinder whereby when one valve is closed, the other is open an vice-versa. An ejector valve located in the ejector nozzle (52) alternately creates vacuum and generate air flow through the vessel (50). The air from the ejector is introduced into the discharge line after closure of the outlet valve.