U.S. patent application number 14/435805 was filed with the patent office on 2015-09-10 for hydroelectric turbine system.
This patent application is currently assigned to Openhydro IP Limited. The applicant listed for this patent is OPENHYDRO IP LIMITED. Invention is credited to James Ives.
Application Number | 20150252547 14/435805 |
Document ID | / |
Family ID | 47018891 |
Filed Date | 2015-09-10 |
United States Patent
Application |
20150252547 |
Kind Code |
A1 |
Ives; James |
September 10, 2015 |
HYDROELECTRIC TURBINE SYSTEM
Abstract
According to the present invention there is provided a
hydroelectric turbine system comprising a base comprising a frame,
and a plurality of legs extending from the frame, the base being
provided with one or more load bearing members in the form of
outriggers extending from the base at a position adapted to resist,
in use, overturning of the base, in particular during extreme tidal
conditions.
Inventors: |
Ives; James; (Dublin,
IE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OPENHYDRO IP LIMITED |
Dublin |
|
IE |
|
|
Assignee: |
Openhydro IP Limited
Dublin
IE
|
Family ID: |
47018891 |
Appl. No.: |
14/435805 |
Filed: |
October 15, 2013 |
PCT Filed: |
October 15, 2013 |
PCT NO: |
PCT/EP2013/071539 |
371 Date: |
April 15, 2015 |
Current U.S.
Class: |
405/195.1 |
Current CPC
Class: |
Y02E 10/20 20130101;
E02D 27/52 20130101; Y02E 10/30 20130101 |
International
Class: |
E02D 27/52 20060101
E02D027/52 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 15, 2012 |
EP |
12188579.2 |
Claims
1. A hydroelectric turbine system comprising a base comprising a
frame, a plurality of legs extending from the frame; and at least
one load bearing member extending from the base at a position
adapted to resist, in use, overturning of the base.
2. A system according to claim 1 in which the base defines an
overturning axis extending between a pair of the legs, the at least
one load bearing member being positioned to resist an overturning
moment acting about the overturning axis.
3. A system according to claim 1 in which the load bearing member
is arranged and dimensioned to be at an elevated position above a
surface of a deployment site when the plurality of legs are engaged
against and supported by the surface.
4. A system according to claim 1 in which the load bearing member
has a load bearing face positioned outboard of the overturning
axis.
5. A system according to claim 1 in which the load bearing member
comprises a leg secured to the base, and a load bearing face
located at a free end of the leg.
6. A system according to claim 5 in which the load bearing face is
oriented such as to be substantially parallel to a seabed or other
support surface on contacting the seabed or support surface during
an overturning event.
7. A system according to claim 1 in which the frame is
substantially triangular and the base comprises three legs, one at
or adjacent each apex of the triangular frame.
8. A system according to claim 7 comprising a load bearing member
extending from each of three sides of the triangular frame.
9. A system according to claim 7 comprising a plurality of the load
bearing members extending from one side of the triangular
frame.
10. A system according to claim 1 comprising a hydroelectric
turbine mounted on the base.
11. A system according to claim 9 in which the turbine comprises an
open centre turbine.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a hydroelectric turbine system to
be secured at a deployment site, for example on the seabed and in
an area of significant tidal flow, which system enables the turbine
to be located securely without risk of overturning, in particular
during extreme weather/tidal events, but without requiring the use
of piling or other complex fixing operations, thus significantly
simplifying the installation of such a turbine system.
BACKGROUND OF THE INVENTION
[0002] The installation of base mounted hydroelectric tidal
turbines has conventionally taken the form of the sinking of a pile
into the seabed, on which pile a turbine or secondary frame
carrying one or more turbines can then be located. However, the
sinking of a pile into the seabed in an area of high tidal flow is
considerably problematic and generally a dangerous operation. In
addition, significant drilling and piling equipment must be
transported to and operated at the site of installation,
significantly increasing the complexity and cost of the operation.
Working at sea with such large and heavy equipment is a dangerous
and time consuming operation, and anything that can be done to
simplify this task and/or decrease the time taken is of great
benefit.
[0003] An alternative system and method for locating hydroelectric
turbines on the seabed or other underwater support surface has
therefore been developed in recent years, which employs a "gravity
base" on which a turbine in mounted, the gravity base utilising the
combined weight of the base and turbine, pressing downwardly into
the seabed via a plurality of legs, in order to maintain the
position and stability of the turbine system without requiring
piling or other complex fixing mechanisms. However, in order to
provide sufficient stability the weight of the base and turbine
must be significant, and must be designed to withstand extreme
tidal events which however generally occur very infrequently. As a
result the system, in particular the base, is essentially over
engineered for normal operating conditions. Thus the turbine and
associated base are large and cumbersome components, and require
significant heavy lifting and transport equipment in order to
achieve deployment and retrieval for maintenance purposes. The use
of such heavy lifting equipment is normally a hazardous
undertaking, and is rendered even more dangerous when this
equipment is operated at sea under difficult and unsteady
conditions.
[0004] It is therefore an object of the present invention to
provide hydroelectric turbine system that overcomes the
above-mentioned problems.
SUMMARY OF THE INVENTION
[0005] According to the present invention there is provided a
hydroelectric turbine system comprising a base comprising a frame,
a plurality of legs extending from the frame; and at least one load
bearing member extending from the base at a position adapted to
resist, in use, overturning of the base.
[0006] Preferably, the base defines an overturning axis extending
between a pair of the legs, the at least one load bearing member
being positioned to resist an overturning moment acting about the
overturning axis.
[0007] Preferably, the load bearing member is arranged and
dimensioned to be at an elevated position above a surface of a
deployment site when the plurality of legs are engaged against and
supported by the surface.
[0008] Preferably, the load bearing member has a load bearing face
positioned outboard of the overturning axis.
[0009] Preferably, the load bearing member comprises a leg secured
to the base, and a load bearing face located at a free end of the
leg.
[0010] Preferably, the load bearing face is oriented such as to be
substantially parallel to a seabed or other support surface on
contacting the seabed or support surface during an overturning
event.
[0011] Preferably, the frame is substantially triangular and the
base comprises three legs, one at or adjacent each apex of the
triangular frame.
[0012] Preferably, the system comprises a load bearing member
extending from each of three sides of the triangular frame.
[0013] Preferably, the system comprises a plurality of the load
bearing members extending from one side of the triangular
frame.
[0014] Preferably, the system comprises a hydroelectric turbine
mounted on the base.
[0015] Preferably, the turbine comprises an open centre
turbine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 illustrates a perspective view of a hydroelectric
turbine system according to an embodiment of the present
invention;
[0017] FIG. 2 illustrates an alternative mounting position for a
load-bearing member forming part of the hydroelectric turbine
system of the present invention; and
[0018] FIG. 3 illustrates a side elevation of the arrangement
illustrated in FIG. 2, when the hydroelectric turbine system is
located on the seabed.
DETAILED DESCRIPTION OF THE DRAWINGS
[0019] Referring now to the accompanying drawings, there is
illustrated a hydroelectric turbine system, generally indicated as
10, for location on the seabed or other suitable underwater support
surface in order to extract energy from the flow of water,
preferably the tidal flow of water, past the system 10, as is known
in the art.
[0020] The system 10 comprises a base 12 for location on the seabed
or other underwater support surface, the system 10 further
preferably comprising a hydroelectric turbine 14 mountable,
preferably releasably, to the base 12 by any suitable means. Thus,
the base 12 acts as a support in order to secure the turbine 14 in
an upright position such that the tidal flow of water passes
through the turbine 14 in order to generate electricity, again in
known fashion.
[0021] In the embodiment illustrated, the base 12 comprises a
triangular frame supported on three legs 18 which each form an apex
of the triangular frame 16. The frame 16 is comprised of three
cross members 20, each extending between a pair of the legs 18.
Each leg 18 additionally preferably comprises a pointed foot 22
extending downwardly from an underside of the respective leg 18. In
use this foot 22 contacts and preferably pierces the seabed or
other underwater support surface, in order to secure the system 10
in position and prevent it from sliding along the seabed under the
influence of tidal forces acting thereon. The frame 16 and legs 18
may be formed from any suitable material, and for example may be
formed from tubular steel of a gauge sufficient to both support the
turbine 14 and resist the loading applied to the system 10 during
use. In addition the base 12 may be of any other suitable shape and
arrangement, and may for example employ more than three of the legs
18 and feet 22.
[0022] In use, when the base 12 is of triangular form as with the
embodiment illustrated, it is preferable to position the system 10
on the seabed or other underwater support surface, such that an
axis of rotation of the turbine 14 is substantially aligned with
the prevailing tidal flow. In the embodiment illustrated the
turbine 14 is mounted such that the axis of rotation is
substantially in line with a longitudinal axis AA of the base 12,
and thus in use the longitudinal axis AA is substantially aligned
with the direction of the prevailing tidal flow.
[0023] In order to maximise the power derived from the turbine 14
during use, it is necessary that the front and rear open faces of
the turbine 14 are positioned normally to the direction of tidal
flow. This does however present a large surface area against which
the tidal flow of water will act, applying significant horizontal
loading to the system 10. As the pointed feet 22 are operable to
prevent the system 10 from sliding laterally along the seabed, the
above-mentioned horizontal loading applied by the tidal flow of
water against the turbine 14, and to a lesser extent against the
base 12, can result in an overturning moment being experienced by
the system 10. While this overturning moment is accounted for in
the design of the system 10, whose weight when on the seabed
renders the normal overturning moment insignificant, during
exceptional tidal conditions this overturning moment may overcome
the weight of the system 10. In such circumstances the overturning
moment will tend to raise the foot or feet 22 at the upstream end
of the system 10 relative to the direction of tidal flow, and may
ultimately result in overturning of the system 10.
[0024] In order to counteract such an extreme overturning moment,
the system 10 is preferably provided with at least one, and more
preferably a plurality of load-bearing members in the form of
outriggers 26 secured to and extending outwardly from the base 12
as hereinafter described. Each outrigger 26 preferably comprises a
leg 28 which terminates, at a free end thereof, with a face 30
which increases the surface area which will come into contact with
the seabed should an overturning event occur. The outriggers 26 may
extend from any suitable position about the base 12, for example
one or more of the cross members 20 and/or one or more of the legs
18.
[0025] The outriggers 26 are oriented and dimensioned such that
when the base 12 is in a normal operating orientation on the
seabed, and thus in a substantially horizontal orientation, the
face 30 of each outrigger 26 is elevated off the seabed, as
illustrated in FIG. 3. This ensures that during installation and/or
recovery of the system 10 the outriggers 26 do not contact the
seabed, which may complicate the installation/recovery, and may
also result in damage to the outrigger 26. However, once the base
12 begins overturning, for example due to rotation of the base 12
about an overturning axis BB defined by a downstream pair of the
legs 18 and associated feet 22, this will result in the face 30 of
each outrigger 26 contacting the seabed, thus preventing further
overturning of the system 10.
[0026] It will be appreciated that the size, shape and dimensions
of the outriggers 26 may be varied in order to provide greater or
lesser resistance to overturning of the system 10. In addition, the
number and location of the outriggers 26 may be varied as required
once the face 30 is positioned outboard of the legs 18/frame 16, or
in other words downstream of the overturning axis BB with respect
to the direction of tidal flow. For example, as illustrated in FIG.
2, one or more outriggers 26 may extend from one or more of the
legs 18 of the base 12. The horizontal distance at which the face
30 of each outrigger 26 is located, relative to a respective
overturning axis of the base 12, will also have a bearing on the
ability of the outriggers 26 to resist overturning of the system
10. It is also envisaged that, due for example to a difference in
surface area of the system 10 being acting on by the tide in one
direction of flow than the other, the overturning moment may be
greater for one direction of tidal flow. It may therefore be
necessary to position and dimension the outriggers 26
accordingly.
[0027] Furthermore, the angle at which the face 30 of each
outrigger is disposed may be selected such that when the face 30
contacts the seabed during an overturning event, the face 30 is
substantially parallel to the seabed or other support surface. In
this way essentially the entire surface area of the face 30 will
contact the seabed in order to maximise resistance to the
overturning moment.
[0028] It will therefore be appreciated that providing one or more
outriggers 26 the overall design of the system 10, in particular
the base 12, can be made lighter, and therefore less costly, and
will therefore be easier to handle and manoeuvre both on shore
during manufacture and transport, and when lowering to the seabed
or recovering therefrom.
* * * * *