| 摘要 |
PURPOSE:To enable accurate measurement of fine velocity of water flow while simple measurement of flow velocity with a freely rotatable needle float adapted to tilt in a sensitive response to the minute velocity of water flow and a sliding plate having a conelike inclined surface and the like. CONSTITUTION:As a casing 1 and a part of an attachment are descended into underground water in an underground hole, the inside of a water flow passage section 6 at the bottom of the casing 1 is immersed in the underground water, while the water level therein is left lower than the underground water surface becuase air is slightly compressed inside the casing. A needle float 7 is immersed in the water leaving the part above the water level and inclines in the direction of flow with a steel ball 10 at the lower end thereof as the fulcrum by a fluid resistance of underwater flow. The fine velocity of the flow can be measured accurately employing a sliding plate 13 having a conelike inclined surface 4, an electrically pressing means and the like as well. |
