| 摘要 |
PURPOSE:To exclude a measuring error, by a method wherein a water storage amount is determined by a pressure sensor having a differential pressure measuring system and pressure reception of atmospheric pressure by the pressure sensor is carried out in the space surrounded by a water receiving part structure and a water storage tank. CONSTITUTION:The air introducing part 4B of a differential pressure sensor 4 is connected to an atmospheric pressure introducing pipe 7 of which the atmospheric pressure introducing port 7A is opened in the space S surrounded by a water receiving cylinder 1, a water receiving funnel 2 and a water storage tank 3 and said differential pressure sensor 4 is constituted so as to sense the pressure in the above mentioned space S as atmospheric pressure. By this constitution, pressure information calcurated by subtracting the pressure corresponding to atmospheric pressure and the change component of pressure applied to water pressure of rain water accumulated in the water storage tank 3 from said water pressure is obtained from the differential pressure sensor 4 and a measuring error contained in a measured value becomes extremely slight and is excluded. |
