The invention relates to an impeller for a pump or turbine, comprising at least one blade, which blade is provided on the pressure side thereof with a standing edge on its outer peripheral edge zone. The invention also relates to a pump for pumping water or a turbine for generating energy from water and having a casing and such an impeller.

The invention relates to an impeller for a pump or turbine, comprising at least one blade, which blade is provided on the pressure side thereof with a standing edge on its outer peripheral edge zone. The invention also relates to a pump for pumping water or a turbine for generating energy from water and having a casing and such an impeller.

A hydraulic machine has a runner of the Francis type, a head cover and a lower cover. A crown has a seal that seals the space between the crown and the head cover against water from the high pressure side. The runner is formed with at least one passage that is capable to drain high pressure leakage water passing the seal to the low pressure side. The passage is formed with an inlet aperture located in a portion of the crown which during operation is exposed to high pressure leakage water. The passage is located within one of the blades and leads from the inlet aperture to the band, where the passage forms an opening leading to the space between the band and the lower cover. The head cover is formed with an air inlet to admit air to the chamber between the head cover and the crown.

A method to dispose at least one air guiding tube between a penstock and a water turbine installed on a dam to form negative pressure at an outlet of the air guiding device by the water kinetic energy produced from high speed of water flow to take in external air for pressurizing, so as to produce a plurality of pressured air bubbles mixed into the water. The water with pressured air bubbles would be decompressed when flowing to an exit of the penstock and has their volumes increased, so as to enhance the water kinetic energy for driving the water turbine more efficiently; meanwhile the method can prevent from production of cavities and further avoid damages of the components of the water turbine from cavitation.

A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

A method to dispose at least one air guiding tube between a penstock and a water turbine installed on a dam to form negative pressure at an outlet of the air guiding device by the water kinetic energy produced from high speed of water flow to take in external air for pressurizing, so as to produce a plurality of pressured air bubbles mixed into the water. The water with pressured air bubbles would be decompressed when flowing to an exit of the penstock and has their volumes increased, so as to enhance the water kinetic energy for driving the water turbine more efficiently; meanwhile the method can prevent from production of cavities and further avoid damages of the components of the water turbine from cavitation.

This method for stabilizing the rotation speed of a hydraulic machine having S-characteristic and comprising a distributor (9) is adapted to modify a water flow, so that the machine can be coupled to a grid. The method comprises the steps of calculating an orientation of the distributor (9); and orienting the distributor according to the calculated orientation. The method further comprises the steps of providing an electric torque to the machine so as to reach a target speed.

This method for stabilizing the rotation speed of a hydraulic machine having S-characteristic and comprising a distributor (9) is adapted to modify a water flow, so that the machine can be coupled to a grid. The method comprises the steps of calculating an orientation of the distributor (9); and orienting the distributor according to the calculated orientation. The method further comprises the steps of providing an electric torque to the machine so as to reach a target speed.

A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.