| 摘要 |
PROBLEM TO BE SOLVED: To make a small-sized and light weight water level retainer and reduce a height and weight of pump equipment.SOLUTION: A water level retainer 4 comprises a water level detection device 18 and an introduction device 19 for feeding water W into a pump casing 6. The water level detection device 18 can detect that a water level within the pump casing 6 has reached the first prescribed water level WL1 that is lower than the upper-most part of the pump casing 6 and that the water level has reached the second prescribed water level WL2 equal to or more than the upper-most part of the pump casing 6. When the water level detection device 18 detects a water level equal to or less than the first prescribed water level WL1, the introduction device 19 is energized to feed water W into the pump casing 6 and when the water level detection device 18 detects a water level that has reached the second prescribed water level WL2, the introduction device 19 is stopped and then the water level in the pump casing 6 is kept.SELECTED DRAWING: Figure 2 |
