| 摘要 |
PROBLEM TO BE SOLVED: To provide a column type submerged pump operable without sucking air from a suction opening even if the lowest water level is lowered to a level lower than a conventional one and capable of reducing ratio of remaining water amount as compared with water retaining amount by reducing remaining water amount in a suction water tank. SOLUTION: A flange part 6 combining a pump casing 2 and a suction cover 3 of a column type submerged pump P as one unit is retained by a flange 40 of a bottom part of a column 4, and a circulating hole 41 is constructed by a plurality of guide blades 41B attached on notch parts 41A provided on an outer circumference region of the flange 40 with intervals in a circumference direction. An open and close part 10 opening and closing the circulation hole 41 is provided on a cylindrical body 9 with an annular float 8. The circulating hole 41 is opened by drop of the cylindrical body 9 according to drop of water level to circulate part of high pressure delivery water to the suction opening 3A by pre-turning the same in a direction same with a rotation direction of the impeller 7. COPYRIGHT: (C)2006,JPO&NCIPI
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