An air injection device for a hydraulic turbine includes: a body having a first end and a second end; an air injection passage extending through the body from the second end to the first end; a protrusion disposed at the first end of the body; and one or more air injection holes disposed in the protrusion.

An air injection device for a hydraulic turbine includes: a body having a first end and a second end; an air injection passage extending through the body from the second end to the first end; a protrusion disposed at the first end of the body; and one or more air injection holes disposed in the protrusion.

A reverse osmosis system includes a membrane unit, an energy recovery device, high and low pressure inlet lines, and a concentrate line. The membrane unit has a membrane, an inlet for receiving a feed fluid, a permeate outlet for discharging a permeate fluid and a concentrate outlet for discharging a concentrate fluid. The energy recovering device has a turbine portion, a turbine inlet and a turbine outlet, a pump portion, a pump inlet and a pump outlet, a motor, and a motor control unit for controlling the motor. The low pressure inlet line is connected to the pump inlet for supplying the feed fluid at a low pressure. The high pressure inlet line connects the pump outlet with the inlet for supplying the feed fluid at a high pressure. The concentrate line connects the concentrate outlet with the turbine inlet for supplying the concentrate fluid to the turbine portion.

A reverse osmosis system includes a membrane unit, an energy recovery device, high and low pressure inlet lines, and a concentrate line. The membrane unit has a membrane, an inlet for receiving a feed fluid, a permeate outlet for discharging a permeate fluid and a concentrate outlet for discharging a concentrate fluid. The energy recovering device has a turbine portion, a turbine inlet and a turbine outlet, a pump portion, a pump inlet and a pump outlet, a motor, and a motor control unit for controlling the motor. The low pressure inlet line is connected to the pump inlet for supplying the feed fluid at a low pressure. The high pressure inlet line connects the pump outlet with the inlet for supplying the feed fluid at a high pressure. The concentrate line connects the concentrate outlet with the turbine inlet for supplying the concentrate fluid to the turbine portion.

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 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 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 system that produces electricity offshore through a fixed installation, including a minimum of; one turbine, one generator, one compressor set, one high voltage subsea cable, and one control center; the generator is a gas driven generator that produces enough power to operate the electric motors, an onshore control center that operate and monitor the system, and all electricity generated through the water turbines and generators are transported to the onshore electricity grid through a high voltage subsea cable.