| 摘要 |
A water control structure for a flow channel comprises a structure-mounted roller assembly having a pair of elongate, generally U-shaped frame members including an upstream leg, a downstream leg and a connecting web therebetween, the frame members adapted to be positioned on opposite sides of the flow channel with the openings in the U-shape facing each other for slidably receiving and supporting in vertically stacked relationship the ends of from one to a plurality of plain flashboards therewithin for providing a height-adjustable gate of flashboards for regulating water levels. A plurality of longitudinally spaced-apart rollers are mounted on the downstream leg for facilitating longitudinal sliding movement of the flashboards in the U-shaped members, each of the rollers comprising a split wheel roller assembly including first and second spaced apart, major diameter roller surfaces. An elongate, longitudinally extending, preferably wedge-shaped notch means is formed in the downstream leg for receiving an elongate, unitary, correspondingly shaped and dimensioned seal means which projects from said notch means upstream into sealing engagment with the flashboards. The upstream leg of the U-shape desirably extends arcuately into the flow channel and curves gently downstream. Multiple elongate, longitudinally extending access passageways are defined in the frame member for facilitating access by various tools and lifting devices to locations along the longitudinal extent of the frame members and to corresponding locations on the flashboards.
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