| 摘要 |
PROBLEM TO BE SOLVED: To provide a drainage shutoff weir allowing a worker to operate it simply and capable of not only preventing a toxic substance from leaking and being diffused by quickly and securely shutting off the drainage containing the toxic substance to prevent pollution from spreading but also being inexpensively installed without occupying a large space when performing the work for handling a load on a road and an outdoor work yard. SOLUTION: This drainage shutoff weir of gate valve type is constituted by installing a slide guide (valve casing) in front of a drain port in a drainage basin to store a sheathing board (valve element) on an inner side of the slide guide and connecting the sheathing board with an opening and closing lid forming a part of a lid for the drainage basin through a permanent magnet. When the sheathing board is connected with the opening and closing lid by magnetic force, the sheathing board is positioned in an upper part of the slide guide to open the drain port in the drainage basin. However, when at least a part of the opening and closing lid is lifted and the external force being equivalent to the force exceeding the magnetic force is applied between the opening and closing lid and the sheathing board, the sheathing board is separated from the opening and closing lid and lowers vertically on the inner side of the slide guide due to its self-weight to block the drain port. COPYRIGHT: (C)2009,JPO&INPIT
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