Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HYDRO TURBINE
FIELD OF THE INVENTION
The present invention relates generally to an underwater turbine.
BACKGROUND OF THE INVENTION
There are a number of devices taught in the prior art for converting
energy from the flow of a fluid (such as air or water) to electrical energy.
For example, US Patent 4,412,417 teaches a turbine arranged to be
anchored on the surface of a body of water for converting "wave energy" to
electrical
energy. The device includes a shaft having a helical flight displaced
therearound.
The flight is not enclosed and the waves passing along the flight causes the
shaft to
rotate, thereby generating electrical power. US Patent 4,849,847 teaches a
similar
floating turbine that floats on and is exposed to a body of water.
US Patent 5,664,418 teaches a turbine arrangement including vanes
for concentrating the wind.
One difficulty faced by devices such as these is that the flow intensity
of the fluid, whether wind or wave, is highly variable and dependent upon
weather
conditions. That is, in conditions wherein there is little or no wind, the
above
described device would not produce much power, whereas a strong wind could
lead
to conditions which would damage the device. As such, these devices are
impractical, as the amount of electrical power generated at a given time is
highly
variable and unpredictable. This is not the case with underwater currents,
which are
generally more constant both in terms of intensity and direction, making
underwater
currents more suitable as potential sources for electrical power.
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US Patent 4,219,303 teaches an underwater power plant which
includes electrical generators and machine rooms within the device. Clearly, a
device such as this is simply too large for use in streams or rivers and is
suitable
only for use in ocean currents.
US Patent 4,025,220 teaches a turbine for use in water or air which
includes a"flexible fluid current collector" for increasing the flow of a
fluid, the device
being arranged for use in either air or water. It is of note that the
collector described
is composed of fabric.
Clearly, a device that is arranged for generating electrical power from
underwater currents that can also be used in streams and rivers and the like
is
needed.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a
water driven turbine for converting the energy of an underwater current
comprising:
't 5 a hollow tubular open ended housing, said housing having an entry
end for accepting the water and an exit end for releasing the water;
a shaft mounted within the housing, said shaft arranged to rotate within
the housing about an axis of rotation;
a generator supported adjacent the exit end of the housing;
connection means on the shaft for operably linking the shaft to the
generator such that rotation of the shaft generates electrical power;
blade means arranged about the shaft, said blade means extending
along a length of the shaft;
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a funnel mounted onto the entry end of the housing, said funnel having
a mouth and a discharge, said mouth having a diameter greater than the
diameter of
the housing, said discharge having a diameter approximately equal to the
diameter
of the housing;
tether means supported adjacent the funnel at the entry end of the
housing for stabilizing the water driven turbine; and
buoyancy means adjacent the exit end of the housing for supporting
the generator;
wherein the discharge of the funnel is mounted onto the entry end of
the housing such that the water entering the funnel at the mouth passes
through the
housing and contacts the blade means, thereby rotating the shaft and
generating
electrical power.
According to a second aspect of the present invention there may be
provided a water driven turbine for converting the energy of an underwater
current
comprising:
a hollow tubular open ended housing, said housing having an entry
end for accepting the -+vater and an exit end for releasing the water;
a shaft mounted within the housing, said shaft arranged to rotate within
the housing about an axis of rotation;
a generator supported adjacent the exit end of the housing;
conneckion means on the shaft for operably linking the shaft to the
generator such that rotation of the shaft generates electrical power;
blade means arranged about the shaft, said blade means comprising
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helical flights extending along a length of the shaft;
a funnel mounted onto the entry end of the housing, said funnel having
a mouth and a discharge, said mouth having a diameter greater than the
diameter of
the housing, said discharge having a diameter approximately equal to the
diameter
of the housing;
tether means supported adjacent the funnel at the entry end of the
housing for stabilizing the water driven turbine; and
buoyancy means adjacent the exit end of the housing for supporting
the generator;
wherein the discharge of the funnel is mounted onto the entry end of
the housing such that the water entering the funnel at the mouth passes
through the
housing and contacts the blade means, thereby rotating the shaft and
generating
electrical power.
According to another aspect of the present invention there may be
provided a water driven turbine for converting the energy of an underwater
current
comprising:
a hollow tubular open ended housing, said housing having an entry
end for accepting the water and an exit end for releasing the water;
a shaft mounted within the housing, said shaft arranged to rotate within
the housing about an axis of rotation;
connection means on the shaft for operably linking the shaft to a
generator such that rotation of the shaft generates electrical power;
blade means arranged about the shaft, said blade means extending
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along a length of the shaft;
a funnel mounted onto the entry end of the housing, said funnel having
a mouth and a discharge, said mouth having a diameter greater than the
diameter of
the housing, said discharge having a diameter approximately equal to the
diameter
of the housing; and
tether means mounted on the funnel for stabilizing the water driven
turbine;
wherein the discharge of the funnel is mounted onto the entry end of
the housing such that the water entering the funnel at the mouth passes
through the
housing and contacts the blade means, thereby rotating the shaft and
generating
electrical power.
The generator is preferably positioned behind the exit end of the
housing relative to the mouth of the funnel.
The diameter of the mouth may be approximately twice the diameter of
the discharge.
Fins may be mounted on an upper surface and a lower surface of the
housing for preventing twisting of the water driven turbine. When fins are
provided,
the fins are preferably mounted on the housing proximal to the exit end of the
housing.
Buoyancy means may be mounted on the water driven turbine for
suspending the turbine in water. The buoyancy means may be mounted within the
fins.
There may be two, three or more blade means as desired.
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The funnel preferably includes a lip of fixed diameter adjacent to the
mouth for preventing backflow.
A cone may be mounted to the housing to extend rearwardly beyond
the exit end. The diameter of the cone preferably increases as the cone
extends
rearwardly.
According to yet another aspect of the present invention there is
provided a water driven turbine for converting the energy of an underwater
current
comprising:
a hollow tubular open ended housing, said housing having an entry
end for accepting the water and an exit end for releasing the water;
a shaft mounted within the housing, said shaft arranged to rotate within
the housing about an axis of rotation;
connection means on the shaft for operably linking the shaft to a
generator such that rotation of the shaft generates electrical power;
blade means arranged about the shaft, said blade means extending
along a length of the shaft; and
a funnel mounted onto the entry end of the housing, said funnel having
a mouth, a discharge and a lip of fixed diameter projecting from the mouth for
preventing backflow, said mouth having a diameter greater than the diameter of
the
housing, said discharge having a diameter approximately equal to the diameter
of
the housing;
wherein the discharge of the funnel is mounted onto the entry end of
the housing such that the water entering the funnel at the mouth passes
through the
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housing and contacts the blade means, thereby rotating the shaft and
generating
electrical power.
Preferably tether means are mounted within the funnel for stabilizing
the water driven turbine.
The generator may be positioned behind the exit end of the housing
relative to the mouth of the funnel.
There may be provided buoyancy means adjacent the exit end of the
housing.
When the generator is positioned at the exit end of the housing,
preferably there is provided buoyancy means supporting the exit end of the
housing
and tether means supporting the entry end of the housing.
There may be provided fins supported on the housing adjacent the exit
end of the housing, the buoyancy means being supported within the fins.
The tether means are preferably supported on the funnel.
Various embodiments of the invention will now be described in
conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side view in cross section of the turbine.
Figure 2 is a cross sectional view along line 2-2 in Figure 1.
Figure 3 is a front view of an altemative arrangement of the flight.
Figure 4 is a side view in cross section of an alternative arrangement
of the turbine.
In the drawings like characters of reference indicate corresponding
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parts in the different figures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, a water driven turbine 1 for converting an
underwater current into electrical power comprises a housing 10, a funnel 12
and a
generator 34.
As shown in Figure 1, the housing 10 is tubular, open-ended and
hollow, comprising an inner surface 14, an outer surface 16, a shaft 18, an
entry end
22 and an exit end 24. The shaft 18 is mounted within the housing 10 such that
the
shaft 18 rotates wi#hin the housing 10 about an axis of rotation, as described
below.
The shaft 18 includes flights 20 which extend about the shaft 18 along the
length of
the shaft 18. It is of note that there may be several flights 20 arranged
about the
shaft, depending upon condition and the intended use. For example, Figures 1
and
2 show an embodiment of the invention wherein there are two flights whereas
Figure
3 shows an embodiment having three flights. As will be apparent to one
knowledgeable in the arts, the three flight shaft will have a larger surface
area than
the two flight shaft. In the embodiment shown in Figure 1, the flights 20
extend
around the shaft 18 in a helical or twisted arrangement. Specifically, the
flights 20
are struck by a flow of water passing through the housing 10 which in turn
drives
rotation of the shaft 18, as described below. However, it is of note that
other suitable
arrangements of flights 20 known in the art may also be used. It is of note
that the
shaft 18 may be mounted within the housing 10 in a hub such that the shaft 18
can
rotate freely. The hub is mounted to the housing by a plurality of legs, the
legs being
arranged so as to minimize their interference with water flow through the
water
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driven turbine 1.
The funnel 12 is composed of a rigid material and comprises a mouth
26 and a discharge 28. It is of note that the mouth 26 is arranged to be of a
greater
diameter than the discharge 28 for increasing the velocity and inertial force
in the
flow of water as it passes through the funnel 12 compared to the current as
described below. Furthermore, as can be seen in Figure 1, the decrease in
diameter
between the mouth 26 and the discharge 28 is gradual, so that water is not
forced
out of the water driven turbine 1, as water diverted away from the water
driven
turbine 1 cannot be used to drive the shaft 18 and is in effect wasted energy.
Furthermore, as can be seen in Figure 1, the mouth 26 includes a lip 27 that
is of a
fixed diameter and acts to retain incoming water flow, as described below.
Specifically, in the embodiment shown in Figure 1, the diameter of the mouth
26 is
approximately 50% greater than that of the discharge 28. As a result of this
arrangement, the surface area at the mouth 26 of the funnel 12 is greater than
the
surface area at the discharge 28. Furthermore, as shown in Figure 1, the
discharge
28 is of a similar diameter as the entry end 22 of the housing 10. It is of
note that
other ratios may also be utilized, according to the conditions in which the
water
driven turbine 1 is to be used.
In the embodiment shown in Figure 1, tether means 30 are connected
to the funnel 12 for anchoring the water driven turbine 1 in the waterway.
Specifically, the tether means 30 comprises side cables 36 and top and bottom
cables 38 which are mounted to the front face of the lip 27, as shown in
Figure 1.
The cables 38 are connected to a support structure (not shown) for securing
and
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stabilizing the water driven turbine 1 in the underwater current, as described
below.
In addition, in the embodiment shown in Figure 1, the water driven turbine 1
includes
fins 32 for further stabilizing the position of the water driven turbine 1 in
the
waterway. In the embodiment shown in Figure 1, the fins 32 are mounted on the
5 outer surface 16 of the housing 10 above and below the shaft 18, proximal to
the exit
end 22. Thus, as a result of the tethering means 30 and the fin 32, the water
driven
turbine 1 will not rotate, twist or turn when exposed to the water current,
meaning
that maximum efficiency is retained. That is, the water driven turbine 1
remains
positioned within the water flow such that the maximum flow of water is
directed
10 through the water driven turbine 1. As will be appreciated by one
knowledgeable in
the art, other tether means 30 or fins 32 at other locations along the water
driven
turbine 1 may also be used for stabilizing the water driven turbine 1.
As can be seen in Figure 1, the shaft 18 is operably linked to the
generator 34. The details of the generator are not shown as these will be well
known
to one knowledgeable in the art. It is of note that in the embodiment shown in
Figure
1, the shaft 18 is connected directly to the generator 34 and the generator 34
is
mounted to the housing 10 behind the exit end 22. Specifically, the generator
34 is
mounted to the exit end 22 of the housing 10 by support bars such that the
shaft 18
is connected to the generator in a straight line. In other embodiments, the
generator
34 may be located at a distance to the water driven turbine 1. It is of note
that in
some embodiments the generator 34 may be positioned in a non-linear
arrangement
relative to the shaft 18 using means known in the art.
It is of note that in the embodiment shown in Figure 1, the fins 32
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include buoyancy means 40 within the fins 32 for counter-acting the weight of
the
generator 34. That is, as discussed above, the fins 32 are mounted proximal to
the
exit end 22 and therefore proximal to the generator 34, for counter-balancing
the
weight of the generator 34. As a result of this arrangement, the water driven
turbine
1 does not tilt when in use.
For use, the funnel 12 is mounted onto the housing 10 such that the
entry end 22 of the housing 10 contacts the discharge 28 of the funnel 12. The
water driven turbine I is then lowered into the body of water, below the
surface of
the body of water and the water driven turbine I is positioned such that the
water
current flows through the water driven turbine I as described below.
Specifically,
the water driven turbine I is positioned such that the current in the body of
water
directs the flow of water directly into the mouth 26 of the funnel 12. It is
of note that
the shaft 18 is operably linked to the generator 34, as described below.
In use, as discussed above, the water driven turbine I is positioned
such that the current in the body of water directs water to flow into the
mouth 26 of
the funnel 12 at the lip 27. As discussed above, the diameter of the mouth 26
of the
funnel 12 is greater than the diameter of the discharge 28 of the funnel. As a
result
of this arrangement, the velocity and inertial force of the water flow
increases as it
passes through the funnel 12 from the mouth 26 to the discharge 28. In this
manner,
the inertial force and veloCity of the water is increased relative to the
water flow
caused by the natural current in the body of water. As noted above, the lip 27
is of a
fixed diameter and acts to prevent backflow of the water once it enters the
funnel 12.
Furthermore, once water enters the funnel 12, it must exit through the exit
end 24 of
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the housing 10 and the funnel 12. Thus, the flow of water passes through the
housing 10 at the entry end 22 and exits the housing 10 through the exit end
24. As
the water passes through the housing 10, the water strikes the flights 20,
thereby
driving rotation of the shaft 18. Rotation of the shaft 18 in turn generates
electrical
power at the generator 34. It is of note that the flights 20 are fitted within
the housing
for maximum surface area and minimum clearance within the housing 10 so that
the shaft 18 rotates freely within the housing 10. That is, the flights 20 are
arranged
to have maximum surface area and are arranged about the shaft 18 to maximize
contact with the flow of water, so that electrical power generation is more
efficient.
10 Specifically, once the flow of water enters the water driven turbine 1, it
must pass
over the flights 20. Furthermore, the funnel 12 increases the velocity of the
flow of
water and passes the flow of water directly to the housing 10 without allowing
water
to flow back out of the funnel and escape, as discussed above.
In an alternative embodiment, the water driven turbine I includes a
cone 42 mounted to the housing 10 and extending past the exit end 24, as shown
in
Figure 4. Specifically, the cone 42 is connected to and extends outwardly and
rearwardly from a position on the housing 10 past the exit end 24.
Furthermore, the
cone 42 may be connected to the housing at positions proximal to the exit end
24,
as shown in Figure 4, It is also of note that the cone 42 increases in
diameter while
extending rearwardly from the housing 10, such that the cone 42 is most narrow
at
the point that is mounted to the housing 10 and most wide at the distal end of
the
cone 42 relative to the housing 10. As a result of this arrangement, water
exiting
avoids the turbulence and restraining effect which would result from contact
with the
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flow of water passing outside the device at the immediate exit, and the
expanded
volume available to the exiting water will enhance the velocity of flow
throughout the
device by eliminating some back pressure. Further, the cone will increase the
velocity of flow of the water passing outside of the cone, which in turn will
have a
pulling effect on the water exit from inside the cone, enhancing its velocity
of flow.
Thus, the above-described water driven turbine 1 is arranged for
converting underwater currents to electrical power. Furthermore, the design is
such
that the water driven turbine I can be used in bodies of water such as lakes,
streams and rivers, where prior art water driven turbines are not suitable or
impractical. Specifically, the water driven turbine is arranged to increase
velocity in
a natural water flow and to direct the water over a plurality of flights.
Water passing
over the flights drives rotation of a shaft which is in tum linked to a
generator,
resulting in the production of electrical power.
While the preferred embodiments of the invention have been described
above, it will be recognized and understood that various modifications may be
made
therein, and the appended claims are intended to cover all such modifications
which
may fall within the spirit and scope of the invention.
