| 摘要 |
PROBLEM TO BE SOLVED: To provide a roof weir which has such advantages of conventional flexible membrane weir in common as solves conventional problems of flexible membrane weir, prevents occurrence of V-notches even in the case that the inside of the weir is brought into a low pressure, facilitates the control of the weir height, and enables a lightweight and inexpensive construction. SOLUTION: The composite roof weir is provided with a rise and fall nonflexible weir and a rising and falling flexible membrane weir by charge or discharge of a fluid. The nonflexible weirs and the flexible weirs are connected together in the crossing direction of a watercourse. In particular, it is preferable that the nonflexible weirs are installed in the central part of the crossing direction of the watercourse, and the flexible weirs are installed at both wall sides of the watercourse. COPYRIGHT: (C)2004,JPO&NCIPI
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