LIBRA TOWER FOR WIND TURBINE

PYLONE « LIBRA TOWER » POUR EOLIENNE

English Abstract

The purpose of the invention is to create a tower termed the Libra Tower that
has a
primary function of being sufficiently high for modern wind turbine
generators, is of
relatively simple construction, is non-rigid in structure, and has the wind
turbine on top
of the vertical tower operating in a horizontal and rotatable position.
The secondary function of they Libra Tower is to have the ability of limited
rotation and
thus easily lowering the tower with the turbine to ground level, more or less,
for critical
repairs, without the use of an industrial crane. Thus the "down time" which
can be a
crucial economic factor as well as the untimely inconvenience for its
customers is
reduced. In the event that a storm is being forecasted, the Libra Tower can be
lowered
to the ground level, similar to a ship lowering its sails, and avoid
significant damage.
Once the storm has passed, the tower can be quickly raised and power restored.
This
feature would be especially appreciated after a natural disaster like a
hurricane or an
earthquake when normal electrical grids are inoperative. Thus the Libra Tower
can be
installed not only in inland areas where the wind is economically viable for
turbines but
in remote areas where inclement weather and high winds are the noun.
The Libra Tower is geometrically designed by combining a primary base form of
a 60
degree hexagon, superimposed with a 6 sided 60 degree pyramid tapering to the
apex,
the Libra Scales, and 2 old fashioned wagon wheels with a hand brake.
The dimensions of the structure axe mathematically proportionate; each side of
the
hexagon is 10 meters more or less, and the base of each corner of the pyramid
is fixed at
each vertex of the hexagon, and each corner of the pyramid, acting as braces,
is at a 60
degree angle. Thus the skeletal lattice structure of each corner to the apex
is then 20
meters more or less. This proportion permits a tower to be emplaced in the
centrality of
the pyramid at a height of 35 meters, more or less. The basic building
component of the
tower is a rectangular pre-fabricated lattice structure, the width and depth
are varied
according to the tensile strength that is needed, each is 10 meters in length,
each with
the capability of interlocking with an add-on lattice. This basic building
component is
ideal for mass production.
In order to emplace the tower centrally in the center, the basic pyramid
structure is
halved, each half resulting in a 3 sided pyramid and between each half is a
vertical and
horizontal passage-way throughout of 2 meters, more or less, permitting the
tower to be
installed vertically and also allow for its limited rotation, the whole
complemented by
its necessary support structure.

The altitude of each half pyramid structure, the distance from the apex to the
base, is
17.3 meters, more or less, and this altitude represents one half, more or
less, of the total
height of the tower to be 35 meters, more or less. Two face to face vertical
support
structures in the passageway center support the tower, which is fixed at the
center by a
sufficiently large, permanent horizontal fulcrum axle, that is on a reinforced
plate,
below each apex of the pyramidal braces. This axle holds the Libra Tower in
place
centrally and it also cohesively bridges the two halves. A second removable
horizontal
axle, of similar diameter is installed at the base above the ground level, and
fixes the
tower in a vertical mode when operating, and when removed, the tower is free
to rotate
to an obtuse angle of 150 degrees more or less to a servicing mode. There the
turbine
can be sheltered during cold and snowy weather conditions and servicing can
proceed.
Each axle is secured according to earthquake standards so as to absorb the
vibrations
from the propeller rotors and even minor earthquakes. A buttress at the base
keeps the
base of the tower from over passing the center when it is being raised
vertically. The top
of the tower can be customized to fit whatever design the turbine base has in
order to fit
congruently.
The Libra Scale feature of the Libra Tower is the ballast inserted at the base
that is
equal in weight, more or less, to the weight of the turbine. The turbine may
weigh 750
kilograms, for example and to achieve balance when in rotation, the ballast
must be
introduced in the base structure that is equal to the weight of the turbine,
more or less.
The ballast at its base contributes greatly to the stability of the tower.
The tower structure is reinforced to support the extra weight of the turbine
and the
ballast, especially when in a horizontal position. This is attained by two
"bridge"
trusses, one on the upper side and one on the lower side of the tower. The two
trusses
are supported by a perpendicular diametric arm from the fulcrum axle, and
complemented with the lattice framework radiating to both ends that strengthen
and
stabilize the tower.
The third feature of the Libra Tower is a simulated wagon wheel on each side
of the
tower on the fulcrum axle, acting as a brake and support.
The rim of the wheels are the brake drums and each wheel has 2 brake pads
adjacent to
the rims that are secured on the stationary rectangular structures supporting
the tower.
The brakes on the wheels have cables directly connected to the hand brake at
ground
level and can be activated by an operator so that the turbine is lowered very
slowly or
brought to a complete stop. This an essential safety component.
Winch cables attached to the front bumper of an utility vehicle are used to
raise or
lower the tower. The cables are attached to secure appendages on the top and
at the base
of the tower.
Page 4

Claims

The Technology of the Invention i which an Exclusive Property or Privilege is
Claimed is defined as Follows:
The Libra Tower for Wind Turbine
1. The exclusive properties claimed for the Libra Tower arse
a) It has dual functions; primarily as a standard tower for a wind turbine
generator and thus be in a vertical non-rigid operating mode;
secondarily, the tower serves as a rotating beam so that with the turbine
remaining at the top it can rotate easily from its upright vertical operating
mode position downward 150 degrees, more or less, to near ground level
position, more or less, for maintenance services, then rotated back up to the
upright position. This ability greatly reduces the "down time" of the wind
turbine which can be a significant economic factor and lessens the hardship
to families dependent on the tower for electricity.
An industrial crane is not required like it is for repairing turbines on
modern
rigid high cylindrical towers.
b) An exclusive property is claimed for the ballast, equal to the weight to
the turbine, more or less that is added within the base structure of the Libra
Mower. The tower is then in balance when it is rotated to ground level,
more or less, hence the Libra Scales. When the tower is in a vertical
operating mode, the ballast at the base of the tower provides extra stability
especially when operating in inclement weather.
c) An exclusive property is claimed for the braking system of the Libra Tower
that ensures that the rate of descent of the tower is controlled as it
rotates slowly, or come to a complete stop. This safety technology is
incorporated in the tower and is a necessary feature. The braking system
consists of a large wheel secured firmly on each side of the tower at its
fulcrum axle and it is the outer wheel rim, not the inner drum as in
vehicles, which acts as an outer drum for the 2 hydraulic/mechanical
brake shoes that are fixed permanently on the vertical support structure of
the tower. The wheels are also fixed to the upper and lower bridge truss
supporting the tower ends. The mechanical hand brake that controls the
braking is similar to the emergency brake in a vehicle, and is located at
ground level, under the full control of the operator.
d) The Libra Tower is not rigid and absorbs the "yaw" movement of the
turbine's propeller rotors according to certain earthquake standards.
At times, modern rigid towers have to replace the propeller and inner
bearings of the turbine due to fatigue.
Page 5

Certain Considerations:
The base of the "Libra" tower is the outline of two halves of a hexagon and
the
4 skeletal braces are the corners of a 3 sided pyramid extended to the apex,
each half centrally spaced for the tower itself. The 4 skeletal braces at the
base are anchored to the concrete pad at the 60 degree vertex. This
combination provides the maximum stability geometrically and economically.
The proportionate design can determine the structure for any reasonable lower
or higher tower height that is desired.
The structural framework mainly consists of an interlocking pre-fabricated
rectangular lattice that is normally fabricated locally. The mechanical
framework for the tower and its auxiliaries of winches, and braking
components are commonplace.
In contrast, modem towers are generally of a cylindrical design with a larger
diameter at the base - can be 5 meters in diameter, more or less - and a
smaller diameter at the top for the turbine. This design requires
sophisticated manufacturers to fabricate, and then special trucks are needed
to
transport to the site.
Page 6

Description

CA 02479517 2004-09-15
PATENT PROPOSAL
~.IBRA T~~VEI~
for
W~NND TURBINE
A Tower which has the additional feature of
lowering the 'Turbine to ground level for repair
Name: Alfred L.114athieu. PhD.
m~
signatur a
Date: September 15, 2004

CA 02479517 2004-09-15
Inventor: Alfred L. Mathieu Cover Page 1 of 2
Owner: Alfred L. Mathieu ,
Agent: nil
Title: LIBRA 'TONER F(JR ~INf? TURBINE
Synopsis - cover,page.
Modern wind turbine generators are usually mounted on ~ 50 meter high tower,
more or
less, normally constructed of joined cylinders to the desired height and
firmly secured to
a cement foundation. Such towers are very rigid. In most instances an
industrial crane is
required to hoist each cylindria~al segment into place and finally the turbine
is hoisted on
top of the tower. When an internal repair to the turbine is needed, an
industrial crane is
required to remove the turbine to ground level and then, after servicing, to
re-install it at
the top. An industrial crane can be very costly to accomplish this task.
The proposed patent for the Libra Tower which is assembled by interlocking
multiple
pre-fabricated lattice components is not rigid. The Libra Tower is designed
for
intermediate direct drive turbine systems with an output of wind AC energy of
300 to
500 kilowatt capacity, more or less, for a tower height of 35 meters, more or
less. An
industrial crane is not needed to install or repair the Libra Tower. It is
capable of being
installed and operating in remote or isolated areas of Canada.
The Libra Tower's primary function is to be the tower upon which the wind
turbine sits
in a rotatable horizontal mode so as to capture the maximum wind energy.
Its secondary function is to facilitate needed repairs and maintenance on the
wind
turbine by having the feature of easily lowering the turbine, without removing
the wind
turbine, to ground level and after the needed travail, easily raising the
tower with turbine
to its vertical operating position without an industrial crane. It can also be
lowered just
before severe winds are forthcoming so as to prevent damage and quickly raised
to the
operating position once the storm has passed.
This secondary function greatly reduces the "down time" of the turbine and
becomes a
critical economic factor when the tower is operating in remote areas, in
inclement
weather such as snow, freezing temperatures and high winds and where families
are
dependent on its electrical output.
The Libra Tower is constructed with pre-fabricated components, and is
transportable
in a standard wheel truck trailer. It is easy to assemble on site in 3 days
more or Less. It
can be located in remote locations that have high winds and would be welcomed
by the
indigenous community.
Initials Page 1 of 9

CA 02479517 2004-09-15
LIBRA T~WER FOR WII~zD TURBINE
I)ISCLOSLIRE
a) Field and Background of the Invention
1. Modern towers for wind turbine generators are being built at a higher and
higher
height - 50 meters more or less -- deemed nece ssaa-y not only to attain the
maximum energy from the wind but to accommodate longer propeller blades - 25
meters more or less - in order to increase the generating capacity of the
turbine.
The higher the tower and the longer the rotor diameter is the trend today in
Europe for wind turbines.
Individual wind tower turbines are rare. Commonplace are wind fauns with
several to as man as hundreds, even thousands of turbine towers, either along
the
coast line as in Denmark, England, Sweden and ~iolland or inland as in
California.
The use of wind power to replace fossil fuels for electrical energy has been a
priority for many years in European countries such as Denmark, Spain,
France, Sweden and the L1K. The manufacturers have developed sophisticated
wind turbines with features such as direct drive, AC current and digital
controls.
European are the main designers and manufacturers of modern high tech direct
drive AC wind turbines with towers as high as 70 meters, more or less and
propeller blades 30 meters in length, more or less. Ciamesa Eolica of Spain
can
provide a product range ofturbines with a rated power from 660 kW to 2.0 MW
with a rotor diameter ranging from 47 to 83 meters
The United States has pioneered the classic wand vane multiple blade windmills
that have been used since the early 1900's for pumping water in ranches and
farms throughout the country. They are still available today.
The Tennessee Valley Authority (TVA) presently has three wind turbines on
Buffalo Mountain, and each is capable of generating 660 kilowatts of
electricity.
The turbines sit atop towers that are 213 feet tall and each turbine has 3
blades,
each being 75 feet long. TVA is planning on expanding the wind power project
over time.
California is the state that has expanded the use of wind energy over the past
50
years. As of 1999, the Tehachapi Wind Resource area in Kern County is the
largest wind energy producer in the world with over 4,600 wind turbines
collectively producing 1.4 billion kilowatt-hours of electricity per year.
The Palm Spring Wind Energy project in southern California has over 4,000
separate windmills, and generate sufficient electricity for Palm Springs and
the
Initials~~~ Page 7 of 9

CA 02479517 2004-09-15
entire Cochella valley. The largest tower with turbine stand I50 feet tall
with
propeller blades as long as 75 feet, and the high tech megatowers are
engineered
in cooperation with NASA and nursed by federal and state subsidies.
China is seeking to supply large wind turbines that are cost effective and
reliable
in operation to meet the growing demand of wind farms in the country. Since
1986 wind farms have been constructed with an installed capacity of 14 MW in
various areas of Ghina. It has been analysed that the S00 KW wind turbine is
the
commercially economic type that is favored for manufacture and use for its
planned wind farms. It is intent on establishing demonstration and
experimentation wind farms to determine the optimum turbine capacity for the
different wind velocities in the country.
China's goal din 1995) was to upgrade its installation capacity to 100 MW
annually.
Canada has been slow to adopt wind power as an energy source but is now
progressing hurriedly. Its total installed wind turbine capacity in the
provinces of
Alberta, British Columbia, Saskatchewan, ~ntario, Quebec and the Yukon is
currently 341 MW. There apparently is no wind turbine installations in
Newfoundland/Labrador, New Brunswick, cat Manitoba, Territories of the North
West and Nunavuk.
Patent Search
A preliminary patent search of the Canadian and USA data base did not show any
towers patented similar to the Libra Tower or any of its features.
The Niche for the Libra_Tower
The use of wind power is expanding exponentia:tly in the industrial world and
with the adaptation of modern technology, there is much competition.
The Libra Tower for wind turbines is designed mainly for the rugged rural
areas
of Canada where inclement weather is the norm and tolerated. It is designed to
compete in the intermediate class having direct drive turbines producing AC
electricity in the range of 300 to S00 kilowatt capacity with a tower height
of 3S
meters more or less.
'The tov~~er is suitable and adaptable fox certain developing countries and
provides a technology that can be maintained by the local community. While the
assemblage of the tower is easily transportable, however many of the
components can be man~,afactured Locally in the selected developing countries.
Initials'~~ Page 8 of 9

Representative Drawing