| 摘要 |
The invention discloses an overshot control gate (26) for use with trapezoidal irrigation channels (10). Gate (26) has a rigid rectangular section (38) adapted to, in use, be pivotally mounted to the base (12) of trapezoidal irrigation channel (10). A pair of triangular sections are pivotally mounted on opposite sides (60, 62) of the rigid rectangular section (38). Each of the triangular sections being divided into first and second triangular sections (44, 46, 52, 54) with a common apex (70, 72) at the base (12) of the trapezoidal irrigation channel (10). Each of the first triangular sections (44, 46) being rigid and adapted to, in use, be pivotally mounted (48, 50) to opposite side walls (14, 16) of trapezoidal irrigation channel (10). Each of the second triangular sections 52, 54) including the pivotal mounting on opposite sides (60, 62) of rectangular section (38) and being formed of a flexible material. Also disclosed is a pipe flow meter (210) and a duckbill valve (200). |
