An underwater current turbine of an underwater tidal-/ocean-/river-flow power plant includes a generator nacelle configured to contain a generator for current generation, a drive unit having at least one rotor blade configured to be driven by moving water and including a shaft connected to the rotor blade for rotation therewith, the shaft extending from the drive unit into the generator nacelle and being configured to drive the generator, and an exchangeable bearing-assembly-and-seal module disposed between the generator nacelle and the drive unit, the bearing-assembly-and-seal module being configured to be removed from the drive unit and from the nacelle as a unit.

A method for driving a transmission mechanism output power in response to an anticipated fluid-pressure gradient field is provided. The method includes sensing the change of direction of pressure gradient field at a desired location from the different area of the transmission mechanism within fluid. The method further includes constructing fluid-pressure gradient field based upon isolation-fluid apparatus or low-density fluid space installed on a transmission mechanism within fluid.

The disclosure provides a sealing system applicable for an ocean power generation device, which includes at least one first seal and a water leakage protection device. The water leakage protection device is located at a side of at least one first seal away from seawater, and includes a sealed water storage tank and a drain pipe. The sealed water storage tank collects and stores seawater leaked from the at least one first seal. One end of the drain pipe is communicated with the sealed water storage tank, and the seawater stored in the sealed water storage tank is discharged through the drain pipe.

A coupling joint includes: joint member which has gear teeth; a center tube which has gear teeth meshing with the gear teeth, and through which a rotational force is transmitted between the joint member via the gear teeth and the gear teeth; a seal member which blocks a lubricated space including a meshing portion of the gear teeth and the gear teeth from the outside between the joint member and the center tube; a lubricant which fills the lubricated space; and a pressure-equalizing member which is provided to face a part of the lubricated space, changes the volume of the lubricated space by deforming in accordance with the pressure of the outside, and thereby equalizes the pressure of the lubricant and the pressure of the outside.

A bearing module for adjusting a rotor blade angle of attack in an underwater power plant includes a rotor-blade shaft, at least two bearings for supporting the rotor-blade shaft, the at least two bearings being axially spaced from each other on the rotor-blade shaft, a first attachment structure for producing a mechanical connection to a rotor-blade hub, a second attachment structure for producing a mechanical connection to the rotor blade, and a third attachment structure for producing a mechanical connection to a blade adjustment mechanism, wherein the bearing module is an installation unit such that it can be assembled at one location and transported to a second location where rotor blades may be attached.

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 system for storing energy includes a body and a shaft having walls defining an internal volume for containing a fluid, a seal member disposed between the body and the walls of the shaft, and a fluid passage in fluid communication with the shaft. The body is disposed within the internal volume of the shaft for movement with gravity from a first elevation position to a second elevation position within the internal volume of the shaft. The seal member divides the internal volume into a first portion located below the body and a second portion located above the body. The fluid passage communicates fluid with the first portion of the interior volume of the shaft. The system further includes a pump/turbine operatively coupled with the fluid passage to drive a motor/generator to generate electricity upon movement of the body from the first elevation position to the second elevation position.

A method for driving a transmission mechanism output power in response to an anticipated fluid-pressure gradient field is provided. The method includes sensing the change of direction of pressure gradient field at a desired location from the different area of the transmission mechanism within fluid. The method further includes constructing fluid-pressure gradient field based upon isolation-fluid apparatus or low-density fluid space installed on a transmission mechanism within fluid.

A sealing system for sealing a rotatable shaft of an underwater turbine against an entry of seawater includes a first seal support and a second seal support arranged axially adjacent to the first seal support along the shaft and a first seal element supported by the first seal support and a second seal element supported by the second seal support. The first and second seal elements each have an annular seal body and a lip extending from the seal body to a sealing surface on or rotationally fixed to the rotatable shaft, and at least one lubricant-filled chamber exists between the first and second seal supports and the shaft.

A hydroelectric power generator, comprising: a plastic seal outer shell;

a skeleton main body, disposed in the plastic seal shell; an embossed flat axis, disposed penetrating in the skeleton main body; an impeller, connected and fixed to one end of the embossed flat axis, to drive the embossed flat axis into rotation;
a magnet, sleeved around the embossed flat axis; a copper coil, disposed around the skeleton main body; a driving plate, connected and fixed to one end of the plastic seal shell, to drive the impeller into rotation; and a plurality of water input bosses, extending slantwise on the driving plate, having water input holes provided thereon. The hydroelectric power generator is simple in structure, easy to manufacture. In which, the slant water input holes on the driving plate are used in cooperation with the impeller, to raise the impact of the water flow.