| 摘要 |
PROBLEM TO BE SOLVED: To resolve a closed state of a jet pump, and, in particular, to resolve a closed state of a jet pump even when comparatively big sedimentary sand is accumulated voluminously in a sand collecting pit.SOLUTION: A sand pumping facility 1 which pumps up sedimentary sand 5 to a sedimentary sand separation unit 20 includes a jet pump 3 which sucks up the sedimentary sand through a suction pipe 3b and pumps up said through a sand pumping pipe L3, a function recovery pipe L4 for sand buried phase which bifurcates from the sand pumping pipe to return the sedimentary sand sucked into the suction pipe to a sand basin W, and switching means V3 and V4 which switches selectively a pipe through which the sedimentary sand sucked into the suction pipe flows between the sand pumping pipe and the function recovery pipe for sand buried phase, wherein making the lifting height of the function recovery pipe for sand buried phase lower than the lifting height of the sand pumping pipe, the sand pumping is performed by the power stronger than the normal time of sand pumping during the closed time of jet pump, and also making the diameter of the function recovery pipe for sand buried phase longer than the diameter of a suction pipe, the closed state of the jet pump is resolved without taking clogging of the function recovery pipe for sand buried phase into consideration. |
