PUMPING PLANT Russian patent published in 1994 - IPC

FIELD: water pumping-out devices of tunnels and mine workings. SUBSTANCE: cavity of centrifugal pump communicates with cavity being dewatered through accumulating tank while with discharge container it communicates through return valve. Automatic pump priming device comprises priming pipe with valve which puts in communication the portions of discharge pipe before and after return valve. The valve is provided with electric operating mechanism connected to power supply by contact of electric relay installed at the output of the NAND gate. One input of said gate is connected to output of water level transmitter in accumulating tank while the other one, to power circuit of pump motor at the point between electric motor and relay contact. Relay winding is connected with output of the second logical AND element whose one input is connected to output of water level transmitter in the container being dewatered while the other one, to power supply which may serve for connecting the pump motor by closing the appropriate contact. EFFECT: improved design. 1 dwg