Abstract: The water-turbine and the intake- and exit-tubes are located in a house, which is supported on stilts from the bed of the headpond. In operation, water is siphoned upwards out of the headpond through the open underside of the house. A trashrack is located in the intake-tube, above the water level of the headpond, whereby the trashrack is in air when the turbine is not running. The trashrack is horizontal.

Abstract: The water-turbine and the intake- and exit-tubes are located in a house, which is supported on stilts from the bed of the headpond. In operation, water is siphoned upwards out of the headpond through the open underside of the house. A trashrack is located in the intake-tube, above the water level of the headpond, whereby the trashrack is in air when the turbine is not running. The trashrack is horizontal.

Abstract: Guide case (24) for use in conjunction with a water turbine (20), with a helical top wall (35) of the annular chamber (27) extended downstream of the inner wall (39) of the inlet port (30). The extension is wetted on its downstream side by the top water entering the inlet port, and on its upstream side by the bottom water. The extension serves to keep the top water separate from the bottom water until the velocity vectors of the two water streams have been aligned, therefore reducing turbulence at the point where the waters mix and merge, and enabling more of the energy to be extracted from the water.

Abstract: Guide case (24) for use in conjunction with a water turbine (20), with a helical top wall (35) of the annular chamber (27) extended downstream of the inner wall (39) of the inlet port (30). The extension is wetted on its downstream side by the top water entering the inlet port, and on its upstream side by the bottom water. The extension serves to keep the top water separate from the bottom water until the velocity vectors of the two water streams have been aligned, therefore reducing turbulence at the point where the waters mix and merge, and enabling more of the energy to be extracted from the water.

Abstract: In a double-ended Francis turbine, shaft whip at critical speed is alleviated by pitching tappets in the housing, around the rotor. The tappets are adjusted to lie closer to the rotor than the (labyrinth) seal grooves. The tappets are of polythene, and are around twenty in number. The tappets are adjustable from outside the housing, and adjustment may be done with the turbine running.

Abstract: In a double-ended Francis turbine, shaft whip at critical speed is alleviated by pitching tappets in the housing, around the rotor. The tappets are adjusted to lie closer to the rotor than the (labyrinth) seal grooves. The tappets are of polythene, and are around twenty in number. The tappets are adjustable from outside the housing, and adjustment may be done with the turbine running.