| 摘要 |
PROBLEM TO BE SOLVED: To provide an underground water level lowering device capable of preventing sudden reduction in a pumping quantity and an air biting phenomenon of a submerged pump without mixing air in the submerged pump, and capable of efficiently checking failure of the submerged pump by efficiently checking the inflow of sand. SOLUTION: This underground water level lowering device is composed of a well pipe composed of a well strainer pipe and a well casing pipe, a support ring fixed to an inner wall surface of the well casing pipe, a suction casing composed of a support plate inserted into the well casing pipe, and supported by the support ring, and an inner cylinder tube having an upper end part passing through the support ring fixed to this support plate in a sealed state, and having a lower end part positioned under the well strainer pipe, a drain pipe having an outer peripheral part fixed in a sealed state by penetrating through the support plate of this suction casing, having one end part positioned in the inner cylinder tube, and having the other end part positioned on the ground, the submerged pump for draining water in the suction casing installed in one end part of this drain pipe, and an air exhauster for exhausting air in the suction casing outside by a vacuum pump arranged on the ground via an air hose.
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