| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drainage device that performs siphon drainage and stops drainage during the drainage, and in addition, keeps a water level constant by automatic drainage, even if the water level of a water storage tank rises, after stopping the drainage. <P>SOLUTION: The drainage device 1 includes a first siphon pipe 3, a trap pipe 4 and a second siphon pipe 5 continuously connected in order toward a drainage tank 6 from the water storage tank 2, a suction pump 72 for sucking air retained in the first siphon pipe, and an atmospheric opening valve 92 for opening the second siphon pipe in the atmosphere. The first siphon pipe, the trap pipe and the second siphon pipe are filled with water from the water storage tank by operation of the suction pump 72, and the siphon drainage is started. Since siphon action is stopped by opening the atmospheric opening valve 92 during the drainage, the siphon drainage is stopped. A storage water level becomes equal to a pipe inside top part of the second siphon pipe, and afterward, even if the storage water level rises, the second siphon pipe automatically drains water for the increase. <P>COPYRIGHT: (C)2012,JPO&INPIT |
