A water power plant for the generation of electric current from a flowing medium by means of a turbine, which includes a housing around which the flow passes on an outer side, a stator of an electric generator which operates in a low-speed mode, and a rotor of the generator, which is rotatably mounted relative to the stator. The rotor includes a rotor ring with an annular surface and, starting from the rotor ring, an arrangement of inwardly extending turbine blades, thereby defining a free-standing axis of rotation. The housing defines an inlet portion with a first front-side cutting edge which delimits a circular inlet opening, from which extends an inlet-side guide surface to the rotor, and an outlet portion with an outlet opening, between which a flow path passing the rotor ring can be formed. It is provided that the inlet opening has a free inlet cross-section which is maximally as large as a cross-sectional area delimited by the rotor ring.

A water power plant for the generation of electric current from a flowing medium by means of a turbine, which includes a housing around which the flow passes on an outer side, a stator of an electric generator which operates in a low-speed mode, and a rotor of the generator, which is rotatably mounted relative to the stator. The rotor includes a rotor ring with an annular surface and, starting from the rotor ring, an arrangement of inwardly extending turbine blades, thereby defining a free-standing axis of rotation. The housing defines an inlet portion with a first front-side cutting edge which delimits a circular inlet opening, from which extends an inlet-side guide surface to the rotor, and an outlet portion with an outlet opening, between which a flow path passing the rotor ring can be formed. It is provided that the inlet opening has a free inlet cross-section which is maximally as large as a cross-sectional area delimited by the rotor ring.

According to an embodiment, the vane 13 has a thick root portion 16P formed on the band 12 side of a pressure surface to be joined to the band 12, with a thickness of the thick root portion 16P being gradually increased toward the band 12, and a thick root portion 16N formed on the band 12 side of a negative pressure surface to be joined to the band 12, with a thickness of the thick root portion 16N being gradually increased toward the band 12. The outlet end 15 has a first curved portion 151 and a second curved portion 152. An extreme point 15B forming a bottom end of the second curved portion 152 is positioned closer to the band 12 than an end of the thick root portion 16P, 16N on the crown 11 side.

According to an embodiment, the vane 13 has a thick root portion 16P formed on the band 12 side of a pressure surface to be joined to the band 12, with a thickness of the thick root portion 16P being gradually increased toward the band 12, and a thick root portion 16N formed on the band 12 side of a negative pressure surface to be joined to the band 12, with a thickness of the thick root portion 16N being gradually increased toward the band 12. The outlet end 15 has a first curved portion 151 and a second curved portion 152. An extreme point 15B forming a bottom end of the second curved portion 152 is positioned closer to the band 12 than an end of the thick root portion 16P, 16N on the crown 11 side.

A startup method of a Francis turbine according to an embodiment includes: a first rotation-speed increasing step in which a rotation speed of the runner is increased by opening the guide vane at a first opening; a second rotation-speed increasing step in which the increase in the rotation speed of the runner is accelerated by opening the guide vane at a second opening that is larger than the first opening after the first rotation-speed increasing step; and a rotation-speed regulating step in which the rotation speed of the runner is regulated to a rated rotation speed by opening the guide vane at a no-load opening after the second rotation-speed increasing step. The first opening is an opening that is half or less than the no-load opening.

A method for in-place machining of a collector ring attached to a turbine shaft of a hydroelectric generator includes: attaching a support member to stationary portions of the hydroelectric generator, the support member being configured to support a machine tool at an angle parallel to an inclination angle of an axis of rotation of the turbine shaft; attaching an adjustable positioning device to the support member; attaching the machine tool to the adjustable positioning device, the machine tool being configured to perform a machining operation on the collector ring; controlling a rotational speed of the turbine shaft to a specified rotational speed by controlling a flow of water through the turbine; adjusting the adjustable positioning device to adjust a position of the machine tool with respect to the collector ring; and performing the machining operation on the collector ring at the specified rotational speed of the turbine shaft.

A hydroelectric turbine designed to operate in a bi-directional reversing water flow caused by ocean waves, comprising an annular stator with two axially spaced sets of a plurality of guide vanes placed along its circumference that are inclined in the axial direction, an annular rotor with a plurality of concavo-convex blades placed along its circumference with an electric generator attached to it. The rotor is placed to rotate about its axis between the two sets of the stator guide vanes. Wherein, the stator and rotor are placed within the cylindrical part of an hourglass-shaped double funnel so when the ocean wave moves in one direction, the water flow enters the turbine through one end of the double funnel (inlet) and passes through the channels formed by one of the stator guide vane sets towards the rotor blades. The channels formed by the stator guide vanes are inclined at an angle to the rotor rotation plane, so that the water flows in the direction of the rotor rotation. After passing through the channels formed by the rotor blades and the channels formed by the other set of the stator guide vanes the water flows out of the turbine through the opposite end of the double funnel (outlet). When the wave moves in the opposite direction and the water flow direction reverses accordingly, the outlet becomes the inlet and the inlet becomes the outlet. The turbine keeps rotating in the same direction, transmitting the rotation to the electric generator and providing continuous high efficiency energy conversion.

A hydroelectric turbine designed to operate in a bi-directional reversing water flow caused by ocean waves, comprising an annular stator with two axially spaced sets of a plurality of guide vanes placed along its circumference that are inclined in the axial direction, an annular rotor with a plurality of concavo-convex blades placed along its circumference with an electric generator attached to it. The rotor is placed to rotate about its axis between the two sets of the stator guide vanes. Wherein, the stator and rotor are placed within the cylindrical part of an hourglass-shaped double funnel so when the ocean wave moves in one direction, the water flow enters the turbine through one end of the double funnel (inlet) and passes through the channels formed by one of the stator guide vane sets towards the rotor blades. The channels formed by the stator guide vanes are inclined at an angle to the rotor rotation plane, so that the water flows in the direction of the rotor rotation. After passing through the channels formed by the rotor blades and the channels formed by the other set of the stator guide vanes the water flows out of the turbine through the opposite end of the double funnel (outlet). When the wave moves in the opposite direction and the water flow direction reverses accordingly, the outlet becomes the inlet and the inlet becomes the outlet. The turbine keeps rotating in the same direction, transmitting the rotation to the electric generator and providing continuous high efficiency energy conversion.

A hand-held turbine cleaning tool includes front and rear housings coupled to each other, an outlet at one end of the tool, and a top of the tool at an opposed end. The outlet is directed in a first direction away from the top. An inlet is disposed between the outlet and the top and is also directed in the first direction. A diverter valve at the inlet is moveable between on and off positions. The on position directs water flowing into the inlet from the inlet, up to the top in a second direction opposite the first direction, and then down to the outlet in the first direction. A turbine at the top has a turbine shaft that extends outside the tool. An abrasive member is connected to the turbine shaft and is configured to rotate when water flows from the inlet to the outlet.

A hand-held turbine cleaning tool includes front and rear housings coupled to each other, an outlet at one end of the tool, and a top of the tool at an opposed end. The outlet is directed in a first direction away from the top. An inlet is disposed between the outlet and the top and is also directed in the first direction. A diverter valve at the inlet is moveable between on and off positions. The on position directs water flowing into the inlet from the inlet, up to the top in a second direction opposite the first direction, and then down to the outlet in the first direction. A turbine at the top has a turbine shaft that extends outside the tool. An abrasive member is connected to the turbine shaft and is configured to rotate when water flows from the inlet to the outlet.