| 摘要 |
PROBLEM TO BE SOLVED: To restrain noise caused by suction of air, and to prevent siphon passage in a rising-up/falling-down gate with a siphon from being clogged. SOLUTION: In this roof gate for arranging the siphon passage 15 reaching a downstream side delivery port 14 from an upstream intake port 13 in a rise and fall door body 1, an inlet 12 of a siphon pipe 7 forming the siphon passage 15 is positioned in the door body 1. The upstream side intake port 13 is opened and closed according to rocking of a cover 18 arranged in the door body 1. A water flow is sucked in from the inlet 12 of the siphon pipe 7 by a blocking-up space in the door body 1. When securing a distance S up to the inlet 12 of the siphon pipe 7 from the intake port 13, the water flow is horizontally stabilized to cover the inlet 12 of the siphon pipe 7. When raising and lowering the door body 1, the cover 18 is closed to check the inflow of earth and sand and a stone to the siphon passage 15.
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