Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SUPPORT APPARATUS FOR UNDERWATER POWER GENERATOR AND METHOD
FOR DEPLOYMENT
Field of the Invention
The present invention relates generally to support apparatus for supporting
underwater power generators and apparatus and methods for the deployment of
underwater power generators.
Background Art
Underwater power generators typically include turbines to convert energy of
marine and water currents into usable power, usually electrical power. These
underwater power generators are generally difficult to install on vatuable
sites, partly
because the sites are deep below the surface of any body of water. Also,
difficulties are
encountered due to the water currents at those valuable sites being powerful
as well as
substantially or generally constantly flowing, even though the water current
flows may
vary in strength and water current flow direction from time to time.
The forces generated by the water currents are high, increasing the stresses
on,
and therefore often the weight of, deployment components. This can hamper
deployment and installation of the underwater power generator.
Known apparatus for supporting underwater power generators are limited in that
they are difficult or complicated to install. Some are held by a complex
system of
anchors, floating pontoons and are suspended from cables in a pelagic region
of the
water. Others are mounted on piles driven into the sea bed. Still others
involve a
complicated system of submerged adjustable decks. In order to install a system
which
can power a useful area such as a medium-sized coastal town, these systems
involve
huge expense.
The present inventors have developed a new deployment apparatus and method
suitable for use with underwater power generators.
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Summary of Invention
In accordance with one aspect of the present invention there is provided a
support apparatus for support of an underwater power generator having a power
generating portion, the support apparatus including:
a stand adapted for supporting the power generating portion, the stand
comprising a stabiliser including one or more stabilising footing elements
adapted to
mount one or more monolithic ballast masses;
wherein the stabilising footing elements include a locating assembly having
locating region adapted to cooperate with a locating region on the or each
monolithic
ballast mass so that the support apparatus in use is weighted down in a
selected
position on a sea bed.
Optionally the locating region on the or each stabilising footing element
includes
a male portion for interengagement with a cooperating female portion on a
ballast mass.
Optionally the male portion includes a plinth or ridge or a key extending from
and/or
along the stabilising footing element. Optionally the plinth or key or ridge
extends
radially and horizontally along the stabilising footing element so that the
ballast mass,
when mounted on the stabilising footing element, is disposed in a
corresponding radial
and horizontal orientation. Optionally there are provided slanted shoulders
depending
downwardly and outwardly from a side portion of the key so that they may
support the
location of a ballast mass having cooperating downward sloping underside
portions.
Optionally the locating assembly includes a stop so that the ballast masses
may
locate thereagainst when installed on a respective stabilising footing
element. The stop
may be a shoulder; optionally it is one or more posts extending upwardly from
the or
each stabilising footing element. Optionally the posts are arranged in pairs,
two per
stabilising footing element, generally or substantially on a common pitch
circle diameter
having its centre disposed on a stand centre.
The or each stabilising footing element may be disposed at a selected distance
from the stand centre by a plurality of spokes extending radially from the
stand centre.
The stabilising footing element may be a plate and may comprise the preferred
locating
assemblies disposed at various locating assembly regions on the plate
distributed from
proximal the stand centre to distal the stand centre, at locations near the
outer edges of
the plate. The stabilising footing element may be an annulus having a main
annular
body disposed at a distal end of the spokes. Optionally, however, the
stabilising footing
element includes support foot pads disposed at the distal end of the spokes.
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Optionally the spokes are arranged relative to one another so that they are
spaced at approximately 120 from one another. One spoke may be longer than
another two so that it may provide a stronger support or reaction force in a
particular
direction. For example, one spoke may be llm long while another two may be 8m
long.
It will be appreciated that any suitable length can be chosen for the spokes.
Optionally the support foot pads include grip portions for increasing
frictional
engagement between the sea bed and the stabiliser. Optionally the grip portion
includes
teeth or ribs in base portions of the support foot pads to bite into the sea
bed.
Optionally the support foot pads include a sole portion which has a convex
disposition for increasing frictional engagement with the sea bed, and
offering more sea
bed/teeth engagement.
Optionally the stand includes a pylon portion extending upwardly from the
stabiliser. Optionally the pylon is disposed in a central portion of the
stand. Optionally
the pylon is a hollow cylindrical arrangement suitable for mounting a turbine
head
thereon. The pylon may also include a rotation mechanism for the turbine.
Optionally
the pylon is tall enough to support a horizontally-disposed axial turbine
having blades
approximately 12m in radial length.
Optionally the turbine head includes a first axial flow blade set arranged on
a hub
and disposed so that the first blade set is rotated about the hub under the
influence of
flowing water current from a direction parallel with the sea bed.
Optionally the ballast masses include a recess or keyway as described above.
The keyway is set into a base face and has slanted sides. This facilitates
easy
positioning as will be appreciated when these ballast masses are being located
in the
locating region while being lowered from a sea surface by long cables.
Optionally the ballast masses include upper faces with a similar profile to
that of
the locating assembly's male or ridged or plinthed portion. This is so that
another ballast
mass may be located on top of a first ballast mass in a nesting relationship.
Optionally
the locating assembly's stops or posts are sufficiently long to be effective
in placing a
second or third ballast mass, one atop another. Optionally the ballast masses
are
approximately 200 tonnes in mass and are constructed from steel, concrete or
other
heavy and dense material and shaped to have negative buoyancy. The ballast
masses
could be any mass, including 5 tonnes, 10 tonnes, 50 tonnes, 100 tonnes, or
other
suitable masses.
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In accordance with a second aspect, the present invention provides a method of
deployment of an underwater power generator, the method including the steps
of:
lowering a stand from a surface of a water body to a sea bed;
lowering one or more monolithic ballast masses from the surface of the water
body onto support footing regions of the stand;
wherein the lowering step includes the step of locating the one or more
monolithic ballast masses on one or more cooperating respective locating
regions of the
support footing regions, the cooperating locating regions comprising a key
adapted to
interengage with a keyway on the monolithic ballast mass.
Preferably, the stand is a support apparatus according to the first aspect of
the
present invention.
Optionally the method further includes the step of installing a power
generating
portion onto the stand. In alternative examples, the stand includes a power
generating
portion installed thereon at the time of lowering.
In accordance with a third aspect, the present invention provides a ballast
mass
for ballasting an underwater power generator or power generator support, the
ballast
mass including a locating region in one surface for cooperating with a
cooperating
locating region in a stand of an underwater power generator.
Optionally the locating region is in the form of a keyway or recess.
Optionally the ballast mass includes a key or ridge or plinth in a second
surface
for receiving a cooperating keyway or recess in another ballast mass for
providing a
nesting relationship between ballast masses.
In accordance with a fourth aspect of the present invention there is provided
an
underwater power generating apparatus including a power generating portion,
the power
generating apparatus comprising a stand adapted for supporting the power
generating
portion, the stand comprising a stabiliser including one or more stabilising
footing
elements adapted to mount one or more ballast masses.
In accordance with a fifth aspect of the present invention there is provided a
method of installing an underwater power generator, the method including:
assembling a power generating head on a support stand;
assembling a plurality of ballast masses on locating portions of the support
stand;
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lowering the support stand, ballast masses and power generating head to the
sea floor.
Preferably, the stand is a support apparatus according to the first aspect of
the
present invention.
Throughout this specification, unless the context requires otherwise, the word
"comprise", or variations such as "comprises" or "comprising", will be
understood to
imply the inclusion of a stated element, integer or step, or group of
elements, integers or
steps, but not the exclusion of any other element, integer or step, or group
of elements,
integers or steps.
Any discussion of documents, acts, materials, devices, articles or the like
which
has been included in the present specification is solely for the purpose of
providing a
context for the present invention. It is not to be taken as an admission that
any or all of
these matters form part of the prior art base or were common general knowledge
in the
field relevant to the present invention as it existed in Australia before the
priority date of
the invention disclosed in this specification.
In order that the present invention may be more clearly understood, preferred
embodiments will be described with reference to the following drawings and
examples.
Brief Description of the Drawings:
Figure 1 is an isometric view of an underwater power generator mounted on a
support apparatus in accordance with a preferred embodiment of the present
invention;
Figure 2 is a side elevation view of the underwater power generator of Figure
1;
Figure 3 is a front elevation view of the underwater power generator of Figure
1;
Figure 4 is an plan schematic view of the support apparatus shown in Figure 1
with the power generating head of the underwater power generator removed for
clarity;
Figure 5 is a side elevation view of the support apparatus shown in Figure 1
with
the power generator portion removed for clarity;
Figure 6 is an isometric view of the support apparatus shown in Figure 1 with
the
ballast masses and power generator portion removed for clarity;
Figure 7 is an end elevation view of an optional stabilising footing element
in
accordance with a portion of a preferred embodiment of the present invention,
showing
a type of optional cooperating stack of ballast masses stacked on top of the
footing; and
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Figure 8 is an end elevation view of another optional stabilising footing
element
in accordance with a portion of a preferred embodiment of the present
invention,
showing a type of optional cooperating stack of ballast masses stacked on top
of the
footing.
Detailed description of preferred embodiments:
Referring to the drawings there is shown an underwater power generator
generally indicated at 10, the underwater power generator 10 including a
support
apparatus 12, the support apparatus including a stand 14. The stand 14
comprises a
stabiliser 16 which includes a stabilising footing element 18 in the form of
three support
foot pads 20, 21, 22. The stabiliser 16 includes spokes 23, 24 and 25 having
distal ends
26, 27 and 28 and the support food pads 20, 21, 22 are disposed at the distal
ends of
the spokes 23, 24 and 25.
The support foot pads 20, 21 and 22 include locating assemblies 30 on each
support foot pad. Each locating region 30 is adapted to locate a monolithic
ballast mass
50 on a support foot pad 20, the mass of the monolithic ballast mass acting to
provide
reaction support from marine or water currents for the underwater power
generator 10
so that it is weighted down.
The locating regions 30 include a male portion 31 for cooperation or
interengagement with a cooperating female portion 51 in the form of a keyway
or
channel 52 on the monolithic ballast mass 50 when the monolithic ballast mass
50 is
installed on the support foot pad 20. The male portion 31 includes a plinth or
ridge or
key 32 which is disposed centrally on the support foot pad 20 and extends
along the
support foot pad 20 in a radial direction, parallel each spoke 23, 24, 25. The
plinth or
ridge or key 32 includes sloping ramps or shoulders 33 to facilitate
cooperation and
interengagement. It will be appreciated that the monolithic ballast masses 50
will be
lowered onto the support foot pads 20 on cables from a height of roughly 30 ¨
60m (at
which will be the surface of the body of water). So ramps, sloping shoulders
33 will
facilitate the positioning of the or each monolithic ballast mass 50 onto the
support foot
pads 20.
The locating regions 30 further include stops 34 for locating the monolithic
ballast
masses 50 thereagainst when installed on a respective stabilising foot pad 20.
The
stops 34 may be in the form of posts 35 which are disposed extending upwards
from the
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support foot pad 20, in pairs, two per support foot pad 20, each post 35
disposed on a
common pitch circle diameter.
Each support foot pad 20 includes a grip region 29 on an undersurface 40 for
increasing frictional engagement with the sea bed (not shown). The grip region
29
includes teeth or ridges 41 which may increase biting engagement with the sea
bed for
improved frictional engagement with the sea bed. The undersurface 40 is convex
in
shape to improve frictional engagement with the sea bed.
The stand 14 includes a pylon 15 in the form of a hollow cylinder 17 to
support a
power generating portion 19 in the form of a turbine head 11. The turbine head
11
includes a rotatable mounting portion 13.
The monolithic ballast masses 50 further include an upper profiled face
portion
56 similar to that of the support foot pads 20 so that the ballast masses 50
may stack in
such a way as to nest with each other when resting on one another, and so that
upper
masses may be located with the same ease as the lower masses were on the
support
foot pads 20. The purpose of the key and keyway is also to retain the
monolithic ballast
masses 50 on the support foot pads and on one another during operation of the
power
generator 10.
The monolithic ballast masses 50 are approximately 200 tonnes in mass and are
constructed from steel, concrete or other heavy and dense material and shaped
to have
negative buoyancy. However, it should be appreciated that the ballast masses
are
designed to suit the conditions and local standards and could be any mass,
including 5
tonnes, 10 tonnes, 50 tonnes, 100 tonnes, or other suitable masses.
The spokes 23, 24 and 25 extend outwardly from the pylon and are arranged so
that they are angularly spaced from one another by approximately 1200. One
spoke is
slightly longer than the other, as can be seen in Figure 4 so that that spoke
may provide
more reaction support for the underwater power generator and may be disposed
in a
direction of the strongest marine or water current.
One installation technique is to lower the support apparatus 12 (shown in
Figure
5) to the sea bed in a first movement and the power generating head lowered
and
installed on the support apparatus in a second movement. The ballast masses
are then
lowered onto the pads 20. In an alternative technique, the stand and power
generating
head can be lowered together and the ballast masses then applied to the stand
foot
pads 20. It should be understood that a further option for installing the
power generator
is to lower the entire apparatus 10, including installed ballast masses, from
the surface
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of the body of water to the sea floor in one lift (or lowering operation).
That is, any
combination of lifts (lowering operations) which is suitable for the size and
mass of the
power generation apparatus may be utilised.
It will be appreciated that the ballast masses 50, when being installed, will,
using
one example installation technique, be lowered on cables (not shown) from
above to a
position a few metres above the support foot pad 20 and radially a selected
distance
away from the support foot pad 20. Then, wall 55 of the ballast mass 50 will
be brought
into abutment with the stop 34, then lowered further so that the key 32
interengages with
the keyway 52. Any misalignment of the keyway 52 of the ballast mass 50 with
the key
32 will be resolved by the sloping shoulders or ramps 33. The power generating
head is
then installed on the pylon.
Various kinds of locating regions 30 are contemplated and suitable for use
with
the present invention. The stabilising foot pads 120, 121 and 122 optionally
include a
female locating region 130 as shown in Figures 7 and 8. The ballast masses
150, 250
in these options include a male portion 151, 251 which cooperates with the
female
locating region 130 by extending into when resting thereon. The upper surfaces
of the
ballast masses 151 and 251 are similarly female so as to receive further
ballast masses
in a stack as shown in Figures 7 and 8. The upper surface of a top ballast
mass may be
flat as shown.
The female locating regions 130 may have sloping shoulders to facilitate
positioning. The male locating regions 151 may similarly be cooperatingly
tapered.
There may be two male projections 252 and 253 disposed on each side of a
female recess 231 as shown in Figure 8. This may facilitate grip of the
ballast masses
upon the support foot pads 220 when in position.
It will be appreciated by persons skilled in the art that numerous variations
and/or
modifications may be made to the invention as shown in the specific
embodiments
without departing from the spirit or scope of the invention as broadly
described. The
present embodiments are, therefore, to be considered in all respects as
illustrative and
not restrictive.
