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Title:
MULTI MODE WAVE ENERGY CONVERTER WITH ELONGATED WAVE FRONT PARALLEL FLOAT HAVING INTEGRAL LOWER SHOALING EXTENSION
Document Type and Number:
WIPO Patent Application WO/2017/062528
Kind Code:
A4
Abstract:
A wave energy converter (WEC) utilizing one or multiple floats together forming an elongated wave front parallel (EWFP) float rotatably connected by at least one swing or drive arm to a floating or shore or seabed fixed body or frame, such that the swing arm is rotating about a submerged pivot point on such body or frame and constraining the motion of the float(s) relative to the body or frame. Relative to the direction of oncoming wave fronts and relative to the still water line (SWL), the at least one EWFP float is substantially forward of, and above, the pivot point such that the float concurrently moves both upward and rearward on wave crests and returns both forward and downward on ensuing wave troughs. The rear surface of the EWFP float is substantially arcuate and concave with a radius approximating Its distance from the pivot point.

Inventors:
ROHRER JOHN W (US)
Application Number:
PCT/US2016/055605
Publication Date:
June 22, 2017
Filing Date:
October 05, 2016
Export Citation:
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Assignee:
ROHRER TECH INC (US)
International Classes:
F03B13/14; F03B13/16; F03B13/18
Attorney, Agent or Firm:
LORUSSO, Mark, D. (US)
Download PDF:
Claims:
AMENDED CLAIMS

received by the International Bureau on 29 May 2017 (29.05.2017)

1. A wave energy converting device for converting the energy of waves into electrical power, pressurized fluid, or other useful or transportable energy comprising: at least one elongated float having a float body and a center of buoyancy, which, alone or in combination with adjacent floats, has a wave front width greater than a front to back depth, excluding any float attachments, extensions, or appendages, and having a wave impacting forward face oriented or self-orienting substantially parallel to oncoming wave fronts and having a substantially concave arcuate rear wall with a rear wall lower extension extending substantially beyond and below the float body, such combined rear wall and lower extension having a radius of curvature approximating the arcuate wave-induced motion path of the float rear wall about a float pivot point or float pivot axis and approximately concentric about the pivot point or pivot axis, wherein the combined arcuate rear wall and lower rear wall extension spans an angle about the swing arm pivot point or axis of up to about 180°; a base comprising a fixed body, floating body or frame having at least one base pivot point or base pivot axis to which the at least one float is movably connected by at least one swing arm, which base pivot point or base pivot axis is located substantially aft or down sea of the at least one float's center of buoyancy and substantially below the still water line, wherein the at least one swing arm controls the orientation and path of a wave-induced relative motion between the at least one float and the base; at least one base position restraining, fixing, anchoring, or stabilizing device integral with, or directly or indirectly connected to, the base to determine or maintain its movement, location or orientation, wherein the at least one base position restraining device is selected from the group consisting of mooring lines, submerged or surface mooring buoys, gravity weights, anchors, drag plates, drag planes, water, solid ballasts, floats, vessels, seabed, shorelines, breakwaters, seawalls, docks, piers, platforms, pilings, seabed-affixed or floating towers, and combinations thereof; and, at least one power take-off (PTO) apparatus secured to or within the base and configured to be driven by at least one force generated by the wave-induced relative motion between the at least one float and the base through the at least one swing arm.

2. The device of claim 1 wherein the float arcuate rear wall lower extension extends along the float rear wall substantially below the float body.

3. The device of claim 1 wherein the combined arcuate rear wall and lower rear wall extension spans an angle about the swing arm pivot point or axis of at least about 30°.

4. Cancelled.

5. The device of claim 1 wherein the at least one float is fully submerged with its center of gravity substantially below the pivot point or axis during severe sea states and subsequently raised to the sea surface to resume power generation with calmer sea conditions.

6. The device of claim 5 wherein the at least one float comprises one or more interior cavities, wherein the at least one float is fully submerged with its center of gravity substantially below the pivot point or pivot axis by at least partially flooding one or more of the interior cavities with seawater through controllable apertures and subsequently raising the float to the sea surface where seawater is drained through the controllable apertures before resuming power generation.

7. The device of claim 1 further comprising controllable apertures for permitting the ingress and egress of liquids into the at least one float, wherein the at least one float's mass is increased or decreased by the controlled admission or drainage of seawater through the controllable apertures.

8. The device of claim 1 wherein the float has port and starboard sides, wherein the port and starboard sides are extended forward from the float forward face or rear wall lower extension to prevent waves approaching the port or starboard sides of the forward face from escaping impact with the forward face.

9. The device of claim 1 wherein the base is a partially submerged buoyant frame comprised of at least one vertical spar and having a center of gravity and a center of buoyancy, wherein the center of gravity is substantially below the center of buoyancy, wherein the at least one spar has at least one substantially horizontal drag plate or plane rigidly attached at or near the bottom of the at least one spar.

10. The device of claim 9 further comprising at least one substantially vertical plate attached to the fore, aft or middle section of the horizontal drag plate, wherein the vertical plate is substantially parallel to the at least one float.

1 1. The device of claim 1 wherein the frame further comprises chambers or cavities, internal the frame or affixed to the frame, wherein the buoyancy and the elevation of the base relative to a still water line and its base pivot point or base pivot axis can be increased or decreased by the admission or discharge of seawater from the chambers or cavities of the frame.

12. The device of claim 1 wherein the base has a water plane area, wherein the water plane area of the base at the still water line is substantially less than the water plane area below the still water line.

13. The device of claim 1 wherein the return or rebound from a first wave, following wave-induced lateral motion, of the base pivot point or base pivot axis of the base is substantially delayed beyond the time when the at least one float reaches a subsequent second wave trough by devices selected from the group consisting of mooring buoy drag forces, mooring line-to-frame attachment location, float center-of- buoyancy and center-of-gravity location, the size, location and orientation of hinged or fixed vertical drag plates secured to the base, and combinations thereof.

14. The device of claim 1 wherein the length of the at least one swing arm can be increased or decreased to increase wave energy capture during differing sea state average wave periods and amplitudes.

15. The device of claim 1 wherein the length of the at least one swing arm is increased and decreased during each wave cycle to recover additional wave energy using a second PTO or the at least one PTO.

16. The device of claim 1 wherein the at least one float can swing on the at least one swing arm through a full 360° of rotation about the float pivot point or float pivot axis without float or swing arm mechanical interference with the base.

17. The device of claim 1 further comprising at least one second elongated float and at least one second float pivot point or second float pivot axis, wherein the base contains a second base pivot point or second base pivot axis connected to the at least one second elongated float located substantially aft of the at least one float by at least one second swing arm which controls the orientation and path of wave-induced relative motion between the at least one second float and the base, the at least one second float pivot point or at least one second float pivot axis being located above, below or on the first float pivot point or pivot axis, wherein the at least one second swing arm either drives a second PTO, or is locked into a stationary position relative to the base.

18. The device of claim 1 wherein the at least one swing arm is comprised of two swing arms or swing arm pairs, one substantially above the other and of equal or unequal length, both pivotably connected to the at least one float and the base at two distinct swing arm pivot points or pivot axes such that the orientation of the at least one float and it's wave impacting forward face is controlled throughout the at least one float's wave-induced rotation about the swing arm pivot points or pivot axes.