Fluid reaction surfaces (i.e. – impellers) – Articulated – resiliently mounted or self-shifting impeller... – Sectional – staged or nonrigid working member
Reexamination Certificate
2000-04-18
2001-09-04
Verdier, Christopher (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Articulated, resiliently mounted or self-shifting impeller...
Sectional, staged or nonrigid working member
C416S117000, C416S19700C, C416S240000, C416S24400R, C416SDIG006
Reexamination Certificate
active
06283710
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vertical axis wind turbine rotor having self-fairing vanes, and to a vane structure for such a turbine rotor, improving upon the wind turbine rotor and vane disclosed in the Barnard, U.S. Pat. No. 4,681,512, issued Jul. 21, 1987.
Referring to attached
FIG. 1
, Barnard discloses a wind turbine having a vertical shaft
2
and a mounting hub
4
. The hub
4
is journalled for rotation in a selected direction of rotation R around the vertical longitudinal axis of the shaft. The hub
4
can be journalled on a base, on the shaft
2
, or it can be fixedly attached to the shaft
2
and the shaft journalled on a base. A plurality of vanes
10
a
,
10
b
,
10
c
,
10
d
are disposed quadrantly on the hub
4
. The vanes
10
a
,
10
b
,
10
c
,
10
d
each comprise a frame
12
and a flexible resilient sail
14
secured to the frame. The frame
12
of each of the vanes
10
a
,
10
b
,
10
c
,
10
d
is semi-elliptical in shape, and the sail
14
when full has the shape of a generally cylindrical segment defined by the two planes, one perpendicular to the axis of the cylinder and one at forty-five degrees (45°) to the axis, which intersect along the minor axis of the semi-elliptical frame and a diameter of the cylinder. As the hub
4
rotates in the selected direction of rotation R, the respective instantaneous direction of movement of each vane
10
a
,
10
b
,
10
c
,
10
d
around the axis of the shaft is shown by A, B, C, D. The wind direction is indicated by the arrow W, and numerals
24
and
26
respectively designate the head edge and the foot edge of the sail of a vane.
In the Barnard wind turbine rotor, the sail of each vane is in succession filled when being driven downwind, causing rotation of the hub or hub and shaft, thereby converting wind energy to rotation of structure. A power take-off can be operatively connected to the hub or shaft for performing work, i.e. driving a load. As each sail is, in turn, being driven upwind as the turbine rotor rotates, that sail becomes temporarily faired, i.e., it streams behind the respective vane frame, for diminishing drag. In Bamard, the vane frame shape said to be preferred is a semi-ellipse, i.e. one-half of the intersection of a plane cutting a right circular cylinder at a 45-degree angle to the longitudinal axis of the cylinder.
In the Barnard construction, the center of pressure of each of the vanes
10
a, b, c, d
is higher than the center of hub
4
, thereby creating a rotational moment in the vertical plane through the hub, which applicant submits would contribute to excessive wear of the bearing mechanism (not illustrated) on which the hub
4
is journalled.
SUMMARY OF THE INVENTION
The present invention provides a vertical axis wind turbine rotor having self-fairing vanes wherein the center of pressure on each vane is coplanar with the journal for the hub of the turbine rotor, thereby improving on the wind turbine rotor disclosed in Barnard, by eliminating a source of excess wear in the hub journalling mechanism.
It is an object of this invention to provide a means for connecting the vanes and hub such that the required vane orientation is established thereby.
It is believed that the improvement provided by the present invention will enable construction of larger and more economical vertical axis wind turbines.
REFERENCES:
patent: 1036109 (1912-08-01), Haslinger et al.
patent: 1319766 (1919-10-01), Gracey
patent: 3995170 (1976-11-01), Graybill
patent: 4130380 (1978-12-01), Kaiser
patent: 4134708 (1979-01-01), Brauser et al.
patent: 4191507 (1980-03-01), DeBerg
patent: 4218183 (1980-08-01), Dall-Winther
patent: 4293279 (1981-10-01), Bolie
patent: 4408955 (1983-10-01), Wagle et al.
patent: 4681512 (1987-07-01), Barnard
patent: 4684817 (1987-08-01), Goldwater
patent: 5083902 (1992-01-01), Rhodes
patent: 5299913 (1994-04-01), Heidelberg
Pillsbury & Winthrop LLP
Verdier Christopher
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