Patent ID: 8591178

Claim:
Water turbine apparatus including a water-turbine having a rotor with blades for extracting energy from a flowing waterway, in combination with such waterway, wherein: the waterway includes a headpond and a tailpond, having respective surface-levels, the headpond surface-level being higher than the tailpond surface-level by a hydraulic head of 1.5 m or more; the apparatus is operable: (a) to raise water from the headpond, through an intake-tube, by siphon action; (b) to convey the water to and through the blades of the water-turbine; (c) and to convey the water from the turbine, through an outlet-tube, to the tailpond; the intake-tube is enclosed by a tube-wall; the intake-tube has an open intake-mouth, through which water from the headpond enters the intake-tube; the intake-mouth has a lip or perimeter, which: (a) is defined by the upstream extremity of the tube-wall; (b) is continuous and uninterrupted around the intake-mouth; substantially every point P 1 , P 2 , . . . , etc on the lip or perimeter of the intake-mouth lies underwater, below the level of the water-surface in the headpond; the apparatus includes a trashrack, which includes a grill of spaced-apart bars; the bars are so sturdy, and are so spaced, as to inhibit or prevent water-borne trash from passing through the grill, but to allow water to pass through the intake-tube; the apparatus includes rack-supports, which are effective to support and retain the grill with respect to the tube-wall, inside the intake-tube, downstream of the intake-mouth; and the grill, thus supported, is so located, inside the intake-tube, that substantially all of the grill lies above all of the lip or perimeter of the intake-mouth.