Embodiments of the invention provide a paddle wheel mechanism for a pool cleaner. The paddle wheel mechanism includes a housing with an internal flow area, a paddle wheel shaft supported by the housing, and a paddle wheel supported by the paddle wheel shaft. The paddle wheel includes a base extending along a base width and a plurality of paddle wheel blades extending from the base within the internal flow area. The plurality of paddle wheel blades include a first-type blade with a first blade portion having a first blade width, and a second-type blade with a second blade portion having a second blade width. The first blade width and the second blade width are each less than the base width, and the first-type and second-type blades are arranged on the base in an alternating manner.

An energy conversion device is disclosed. Some embodiments include a mounting system for mounting the device in a fluid, an axle fixed to the mounting system, a hollow shell that rotates about the axle having axial symmetry about a longitudinal axis. The hollow shell may be substantially rounded at the front, expanding to a maximum diameter less than half the distance from the front end to the back end, and tapering radially along the longitudinal axis to the back end. The energy device may further comprise a plurality of blades on the exterior of the hollow shell, each blade extending from the front end of the hollow shell to the back end, rising to a maximum height, and having concave and convex walls. Other embodiments are described and claimed.

A wind or tidal turbine blade having an attachment, the attachment including: a support portion of the turbine blade, the support portion having opposite surfaces; an insert adapted to mount a bolt for attaching the support portion to another structure; and a mounting for fitting the insert to the support portion, the mounting including a layer extending over a front face of the insert and bonded to the opposite surfaces of the support portion on opposite sides of the insert, the layer permitting passage of a bolt therethrough to or from the insert.

The invention provides an energy generation system comprising a generator having charged mutually rotating plate elements, and comprising an integrated drive mechanism for precisely controlling a separation distance between the plates. The drive mechanism provides a separation which varies as a function of the speed of rotation, hence assimilating separation control within the natural operation of the device. Embodiments provide plates comprising self-generating bearings, both hydrodynamic gas and fluid bearings and centrifugal regulator solid bearings, the bearings providing a supporting force between the plates of a magnitude which increases as the rotational speed of the plates increases. Methods of energy generation are also provided.

A hydro turbine assembly includes a hub configured to rotate about a center axis and configured to be mounted in a water passage. The hub includes an upstream end, a downstream end and an outer surface between the upstream and downstream ends. The hub includes at least three mounting recesses arranged in the outer surface wherein each mounting recess includes a first hub mounting surface and a second hub mounting surface, and the second hub mounting surface is downstream and radially inward of the first hub mounting surface. The assembly includes at least three runner blades each including a base configured to seat in a respective one of the mounting recesses, wherein the base includes a first blade mounting surface arranged to abut the first hub mounting surface and a second blade mounting surface arranged to abut the second hub mounting surface.

An assembly of rotor blades and hub for a turbine, such as a tidal current turbine. Each rotor blade includes a cavity and at least two ribs extending into the cavity at a radially inward (lower) region of the rotor blade. The hub includes a journal for each blade and the journal extends into the cavity and is supported by the at least two ribs.

A hydropower generator includes: a driving shaft installed along a path through which a fluid flows; a plurality of blade assemblies installed along a lengthwise direction of the driving shaft; a spinning supporter connected to rotatably support the driving shaft; a power generator receiving a spinning force of the driving shaft and generating electricity; and a flow pipeline internally provided with the driving shaft along a lengthwise direction thereof and formed with a channel through which a fluid flows.

A marine propeller has an outer hub having a central axis and a blade having a blade root attached to the outer hub and extending radially outward from the outer hub toward a blade tip. The blade has a leading edge and a trailing edge. The propeller has a diameter between about 15 inches and about 17 inches and a pitch between about 14 inches and about 24 inches. The blade has a progressive rake angle such that a first local rake angle at the blade root is less than a second local rake angle at the blade tip. A combination of the diameter, pitch, and progressive rake angle provides a marine vessel to which the marine propeller is coupled with minimum drag while the marine vessel is operating at less than a maximum vessel speed. A method of designing a propeller is also disclosed.

A two piece impeller centrifugal pump comprising two halves of an impeller facing each other within a volute, a housing having two sides, one side adjacent each impeller half and having an inlet and an outlet, a motor mounted on the housing, the motor driving both impeller halves, for pumping fluid or material from the inlet to the outlet, the housing and the impeller halves having a sealing surface where they contact each other, the centrifugal force of the impeller forcing the fluid or material outward, pushing the two impeller halves outward against the housing.

A rotor 16 is provided, including a vertical rotation axis 12 and at least two rotor blades 18, 20, 22 arranged on the rotation axis 12, wherein at least one rotor blade 18, 20, 22 includes an opening 60 with an openable closure element 62. Due to the design of the rotor blade 18, 20, 22, the rotor 16 has particularly high efficiency.