Abstract: A stay ring of a hydraulic turbine has: a ring-shaped upper wall, a ring-shaped lower wall arranged below the upper wall forming a ring-shaped flow channel between the upper wall and the lower wall; and stay vanes arranged in array with spaces in a peripheral direction in the ring-shaped flow channel and rigidly secured to the upper and lower walls. The upper wall and the lower wall are inclined so as to reduce height of the ring-shaped flow channel toward outlet at least near inlet end thereof. The straightening bodies are arranged along inner surfaces of the upper wall and the lower wall at least near inlet end to reduce inclination of water flow in the stay ring.

Abstract: A stay ring of a hydraulic turbine has: a ring-shaped upper wall, a ring-shaped lower wall arranged below the upper wall forming a ring-shaped flow channel between the upper wall and the lower wall; and stay vanes arranged in array with spaces in a peripheral direction in the ring-shaped flow channel and rigidly secured to the upper and lower walls. The upper wall and the lower wall are inclined so as to reduce height of the ring-shaped flow channel toward outlet at least near inlet end thereof. The straightening bodies are arranged along inner surfaces of the upper wall and the lower wall at least near inlet end to reduce inclination of water flow in the stay ring.

Abstract: A multistage hydraulic machine is vertically positioned within a pit. The main shaft of the machine is divided into an upper main shaft and a lower main shaft at the location of the lowest pressure stage runner. A side path is provided laterally from the pit so that the lowest pressure stage runner and lower main shaft can be installed and removed through the side path.

Abstract: An apparatus for use in a method for discharging leakage water from guide vanes of a reversible hydraulic machine when the guide vanes are fully closed under the water surface of a runner being depressed comprises a runner connected to a main shaft of the hydraulic machine and covered with upper and lower covers, a plurality of guide vanes arranged at a peripheral portion of the runner, first and second discharge pipes provided with first and second discharge valves and arranged so as to connect a discharge conduit and a runner chamber formed between the runner and one of the covers, and a device for operating said discharge valves. A leakage water discharge method is carried out in accordance with such control mode as that the first and second discharge valves are both opened when the runner rotates in a power generation direction and one of the discharge valves is opened when said runner rotates in a pumping-up direction.