Note: Descriptions are shown in the official language in which they were submitted.
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LOW HEAD, DYNAMIC VARIABLE PITCH, SUBMERSIBLE HYDRO GENERATOR
Claim of Priority
This application claims priority under the United States Provisional
Application No.
60/473,717, filed on May 27, 2003.
Background of the Invention
Field of the Invention. The subject invention is generally related to systems
for
generating and distributing hydro-electric power and is specifically directed
to a micro-hydro-
electric power generating system for producing electricity from low flow
sfireams and the like.
Discussion of the Prior Art. Hydroelectric sites are broadly categorized 'as
"low" or
"high" head. Low head typically refers to a change in elevation of less than
10 feet (3 meters). In
the past, a vertical drop of less than 2 feet (0.6 meters) generally rendered
a hydroelectric system
unfeasible. A high flow rate can compensate for low head, but a larger and
more costly turbine
will be necessary. Typically, prior art turbines do not operate efficiently
under very low heads
and low flow.
The amount of power available depends on the dynamic head, the amount of water
flow
and the efficiency of the turbine/generator combination. To get an idea about
available power in
watts, multiply the head in feet, times flow in GPM, times 0.18 times
efficiency. Turbine
efficiency ranges from 25% to 50%, with higher efficiency at higher heads. To
get a rough idea,
use 0.30 (representing 30%) as a multiplier for efficiency.
An even more desirable and heretofore unachievable objective is to harness the
natural
flows of rivers and streams without impeding the flow via a dam or no more
than a low dam (less
than 6 meters high) to create an artificial head. The problem is that natural
flows in rivers and
streams are highly variable. In certain areas during the driest months of the
year, river flows are
one-tenth of the flows during the wettest months of the year, on the average.
Thus, the small
hydroelectric plant has been found to have little worth as a source of
dependable power capacity.
Achieving full utilization of all of the annual river flow is not a simple
matter when
synchronous generation is involved at small sites. There is a lower limit of
machine capability
which must be accounted for during operation of hydraulic turbines at low
river flow discharges,
which often results in an inefficient, poorly defined and often rough
performance. In the past,
such operation over long periods is not recommended nor guaranteed by
manufacturers of
electromechanical components.
SUBSTITUTE SHEET (RULE 26)
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In the case of low head turbines, those having heads less than 15 meters in
magnitude,
this limit has been fixed at about 40% of the maximum rated machine flow
discharge. But if
asynchronous (induction) generation is utilized, economic factors then permit
splitting the
scheduled available hydroelectric potential capacity of a given site between a
plurality of equally
small powered units which results in a better operative utilization throughout
the more important
portion of the annual available river flow as well as during the remainder of
the year. This
potential, instead of being only 50% for just one machine, is about 80% for
two identical
machines and goes up to 95% when the scheduled power potential is spliced or
joined between
three identical machines, having the same engineered design.
These requirements are typical for hydrological features of the rivers in the
New England
and Mid-Atlantic areas of the U.S.A. Economics in asynchronous generation may
be fuxther
improved if the involved electric generator set is of the capsule-mounted
type, either positioned
upstream or downstream respective to the turbine runner, and whether in a
vertical or horizontal
disposition. These generators can be made of the water-cooled type, having
water-lubricated
sleeve type bearings with the capsule being filled with treated water and
substantially fully
isolated from the polluting waters of the surrounding media. Before
installation, such a machine
is filled with clean neutral water. This water lubricates the bearings and
also cools the electric
windings and the generator can be installed at any depth fully submerged. A
pressure
compensating device will guarantee that any expansion of the water filling
which takes place
when the machine reaches its maximum temperature, is retained and this
prevents surrounding
contaminated or alkaline water from entering due to the temperature drop when
the machine
cools after it is stopped.
An early hydro powered bulkhead assembly attempting to utilize natural
waterways for
the provision of electric power is shown and described in U.S. Patent No.
4,345,159 wherein the
assembly is provided for association with damming or analogous structure
defining a water
passageway through either non-navigable dams, movable-type dams, chambers at
locks defined
for navigation procedures, canal drops or auxiliary locks. The system
described includes a
selectively displaceable body to achieve asynchronous electric generation when
disposed in an
operative position relative the damming structure. Flow controlling means,
such as tainter gates,
chanoine wicket gates, miter gates, and the like are included and operable to
permit overhauling
of the assembly or when in an idle status. A plurality of asynchronous
generators may be spliced
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together in any one bulkhead assembly to enhance the generation quality,
dependent upon the
requirements imposed by extreme, highly variable hydraulic heads.
U. S. Patent No. 4, 476,396 shows a hydroelectric generating system for use
with low-
head dam and spillway installations. A vessel in the form of a barge contains
ballast tanks,
pumps and associated structure permitting the vessel to selectively float or
to be submerged at a
spillway. The vessel contains a plurality of horizontal penstock and draft
tube passages extending
therethrough each containing a turbine for generating electricity. The vessel
is of such
configuration as to be floated into the gate of a dam spillway wherein the
water flowing
therethrough passes through the vessel passages energizing the turbines to
generate electricity.
Anchor apparatus defined adjacent the spillway and complimentarily shaped
abutments defined
upon the vessel cooperate to maintain the submerged operative position.
A number of dam installations exist in major rivers for flood control
purposes, and such
dams include a plurality of gated spillways for controlling the water level.
Low-head
hydroelectric generating apparatus mounted within such spillways would
effectively utilize the
water flowing therethrough for electric generation purposes.
It is known to utilize low head systems for hydroelectric generation within
rivers having
flood control dams and spillways. This has not found widespread usage for a
number of reasons.
Low-head generating systems may utilize the flow of the current for motive
purposes, and such
devices are shown in U.S. Pat. Nos. 3,978,345; 4,142,823; 4,163,904 and
4,301,377.
Hydroelectric generating systems of the siphon type also have been used in low-
head
installations, and a sample of such apparatus is shown in U.S. Pat. No.
4,117,676. However,
during the river flood stages which annually occur such hydroelectric
generating apparatus
would interfere with the flow of water through the spillways, functioning as a
gate, and seriously
affect the flood control purpose of the dam. For this reason, hydroelectric
generating apparatus
has not previously been utilized with low-head dams and spillways of the flood
control type in
view of the problems arising during high water.
There remains a desire and need to provide stable, efficient and economical
electrical
power to many areas of the world. Use of natural waterways to provide this
power continues to
be a desirable, but heretofore unattainable, solution. Even in countries with
extensive grid
electrification, small communities are often not connected because of the high
costs of step-down
transformers and low revenues. Local hydroelectric systems would provide
electrical power
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with much lower long term costs per kilowatt than solar, wind and diesel
systems. However, this
market is largely untapped because reliable hydro technology is not available
or where available
it is generally too expensive and still of dubious reliability.
Summary of the Invention
The subject invention is directed to a hydroelectric generator system or hydro
generator
having a base which is adapted to be installed in a flowing stream of water
generally
perpendicular to the flow of water for defining an upstream side and a
downstream side. A rotor
is mounted for rotation about its axis in the base, and a plurality of hinged
are vanes mounted to
and extend radially outward from the rotor. The vanes are designed to open to
a fizlly extended
position on the upstream side during a portion of rotation of the rotor and to
closed to a nested
position during a portion of rotation of the rotor, wherein the flow of water
from the upstream
side to the downstream side impinges upon the vanes and opens them to the
fully extended
position to drive the rotor. The rotor or the rotor and vanes may be
completely submerged.
In the preferred embodiment, the base includes a vane receptive channel for
receiving and
collapsing the vanes into a nested, closed position during the portion of the
rotor rotation cycle
wherein selective of the vanes are in communication with the channel.
Typically, the base
includes an upstream wall and a downstream wall and wherein the upstream wall
is higher than
the downstream wall.
Preferably, the rotor extends the span of the waterway and the vanes extend
the length of
the rotor. The rotor may include a positive stop for defining the fizlly
extended position of the
vanes. End caps, mounted on either the rotor or the vase define a closed
cavity between adjacent
vanes. Preferably, each vane is concave curved relative to the upstream side.
A siphon drain may be included between the upstream side and the downstream
side of
the base.
An electric generator is provided and a drive shaft for driving the generator
is driven by
the rotation of the rotor.
In operation, the base and rotor are submerged in a running stream of water,
with the
rotor horizontally mounted, with a plurality of hinged vanes which open to
catch the water as it
runs over the top, hold the water as it is lowered during rotation, release
the water when it is
lowered a predetermined amount, and close to allow for submersed rotation with
minimal losses.
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One useful application of the invention provides for the retrofitting of high
head dams to
create a ship ladder downstream of the dam where each step of the fish ladder
is created by a
submersible hydro generator. The fish ladder to allow for the entire flow
capacity of the river.
The hydro generator of the subject invention is capable of producing reliable,
efficient
electrical power in a low head stream. In the preferred embodiment the
assembly uses a low
vertical drop for providing an efficient, reliable generator without requiring
a dam. In one
embodiment, a vertical drop of one meter with a rotor length of 10 meters can
produce a power
output of 0.2 Megawatt. The rotor operates at the same speed as the natural
water flow and
therefore, is environmentally friendly to certain species such as salmon. The
system provides an
environmentally desirable, efficient, non-polluting source of reliable power
which can be
generated close to the point of consumption. This makes the system of the
subject invention
particularly useful in those regions of the world where power grids are not
readily available. The
system is also useful in enhancing power generation capacity in grid supported
regions for a
fraction of the cost of new power plants and without pollution.
In one embodiment, a plurality of units can be placed in a series of one meter
drops (or
other suitable increment) to provide a fish ladder for migrating salmon while
generating power.
This would allow and existing dam to stay in place while providing a solution
to the requirement
that functional fish ladders be provided. In the example, the fish ladder
itself provides power
generation.
In the preferred embodiment of the invention, the includes a base for
supporting a
substantially horizontal spindle extending the span of the waterway. Vanes are
attached to the
spindle using hinges. A power shaft is supported by the spindle. In the
preferred embodiment
the vanes are concave curved on the upstream side. The assembly is placed in
the waterway and
spans the breadth of the waterway such that this causes a level rise on the
upstream side. The
water is forced to flow over the top of the unit, sweeping the hinged vanes
upward and away
from the spindle. This causes the vanes to extend upward and outward from the
spindle via the
hinge until it reaches a positive stop. The vane then transmits the flow
energy to the spindle and
causes it to turn. Once each vane passes over center and is on the downstream
side, it may be
partially collapsed toward the spindle by a constriction plate. This prevents
the water carried by
each vane from being carried back by the vane to the upstream side and
maximizes the efficiency
of the system.
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In the preferred embodiment a siphon break is provided for allowing air into
the ends of
the rotor assembly.
The vans rotate at the speed of the natural current and are spaced to permit
salmon to
swim upstream through the assembly.
The preferred assembly comprises a horizontally mounted cylinder rotor with a
plurality
of hinged vanes attached to the rotor to swing in the same radial direction.
Means are provided,
for operating the vanes to catch water in trapped channels as it flows over
the system to permit
the rotor to rotate while fully submersed. The rotating rotor is used to
provide power for
generating electricity.
Brief Descriution of the Drawings
Fig. 1 shows the working mechanism of the hydro generator and the base above
which
the rotor will mounted.
Fig. 2 shows a cross-section of the assembly with the action of water upon the
mechanism by the flow arrow.
Fig. 3 shows the end caps, which will contain the bearings supporting the
rotor above the
base.
Fig. 4 shows one version of the spindle to which the hinged vanes will be
attached.
Fig. 5 shows a front view sketch that includes the generator, rotational power
transfer
module, shaft seals, drain annulus, bearings, and coupling flange.
Fig. 6 shows a single hinged vane, which would attach to the spindle in Fig.
4.
Fig. 7 depicts the a cross section of the operation of a hydro generator with
fish present to
illustrate how the unit would operate without harm to fish.
Fig. 8 shows a system which would use the hydro-generators to retrofit a
hydroelectric
dam.
Detailed Description of the Preferred Embodiments
The basic working assembly is shown in Fig. 1. A base 10 is provided and is
adapted to
be mounted on the floor of the water way. The longitudinal axis of the base
extends the breadth
or span of the waterway and is perpendicular to the direction of flow. In the
preferred
embodiment the base is constructed of a heavy inert material such as rebar
reinforced concrete.
The base could also be formed of high strength plastic, being hollow for fill
with concrete at the
point of installation. The base include a formed channel 12 for accepting
spindle and vane
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assembly 14. The upstream side 16 of the base is higher than the downstream
side 18 and with
the vane assembly assures that the water enters the system above the rotating
axis 20 of the
spindle 22. An axial power shaft 24 is attached to the spindle. Then arrow 26
indicates the
direction of rotation.
Typically, the spindle 22 is made of a material with high rigid strength and
high fracture
toughness, such as fiberglass composite, high strength plastic, or corrosion
resistant metal. The
spindle consists of a central cylinder as seen in Fig. 1 or, in the
alternative as shown in Fig. 4, of
a cylindrical core shaft 33, extending radial plates 32, and axial water
containment plates as or
end walls 31. The spindle must be constructed of material of sufftcient
strength to bear the
forces applied by the water.
As shown in Fig. 1, the vanes 28 extend the length of the spindle and are
concave curved
toward the upstream side 16 of the base. The vanes are made of a high strength
material which is
buoyant in water at standard temperature and pressure conditions, and can be
molded into the
required shape or otherwise manufactured to meet their shape, strength and
buoyancy
requirements. The concave curve is designed to let the vanes nest against the
spindle as shown in
Fig. 1 when the vanes are in the base channel 12.
The vanes 28 are each individually attached to the spindle 22 by a hinge 30,
as shown in
Fig. 6. The hinges could be of separate construction and bolted or riveted to
the spindle and
vanes, or molded into the ends of the spindle extending plates and the butt
ends of the vanes for
single pin assembly, in the manner that traditional pinned hinges are
constructed. The vanes
might have a small section with an opposite concavity 34 on the vane tip, as
shown in Fig 6, in
order to assist the water in sweeping the vane away from the spindle. The
vanes shown in Fig. 6
are shown attached to the plate type spindle of Fig. 4, as attached to each
individual plate 32.
However, it should be understood that the vanes would be similar attached to
any configuration
of the spindle.
The drive shaft 24 (Fig. 1), may be a separate keyed-in piece or an integral
part 33 of the
spindle assembly as seen in Fig. 4
The cross section of the basic working mechanism is shown in Fig. 2. This
illustrates that
when the vanes 28 are hinged onto the spindle plates 32, they must be done so
in a manner that
provides a backstop or positive stop 40 for the vanes. In Fig 2 the hinges 30
are shown being
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attached on the upstream side (concave) side of the vanes so that the butt of
the vane must stop
against the end of the spindle extension plates to provide the positive stop..
As shown in Fig. 2, the water flows into the assembly from the upstream side
and hits the
first nested vane 28a. This forces the water up, and above the axis of the
spindle, and drives the
spindle clockwise as indicated by arrow 42. As the spindle 28a is released
from the upper edge
44 of the channel 12, the water forces the spindle to the fully extended
position as indicated at
spindles 28b, 28c and 28d. The spindles will stay in the fully extended
position until forced to
nest in the channel 12 of the base, as shown at spindles 2~e, 28f, 28g and
28h. This forces any
water in the spindle cavity outward from the assembly in the direction of the
flow. It also
assures that any debris or animal life in the assembly is expelled without
damage to the life or the
assembly as the spindles rotate back to the position of spindle 28a.
The rotor assembly includes end caps 53 as shown in Fig. 3 and Fig. 7. The
rotor shaft
51 (Fig. 3) extends through the end caps and be supported with bearings 52 of
sufficient rating to
support the weight of the rotor assembly, the forces acting upon it from the
weight of the water,
and the impulse of the water current. In the preferred embodiment, the
bearings are mounted into
the end caps. The end caps should be made of a material of high strength, such
as fiberglass
composite, high strength plastic, or corrosion resistant metal. The end caps
should have
integrated into them, a siphon break channel 54 extending from the top 56 of
the end cap to an
area 58 just below the core shaft area of the spindle. The siphon break is
open only at the top 56
of the end cap and at the area 58 below the core shaft 51 of the spindle. The
opening at 58 is to
the interior of the assembly, or in the cavity occupied by the rotating vanes.
The front view complete spindle assembly without the base front wall 16 being
visible is
shown in Fig. S. The complete assembly has two bearings 66, 67 on the
generator end. The use
of two bearings at this end may or not be necessary. The use of a drain
annulus 74 with dual
shaft seals is located between the power transfer module 59, shown here as a
shaft 60, pulley
drum 69, and synthetic cord type, but it could be gears or belts, or sprockets
and chain, and the
rotor assembly. The drain annulus, drum casing, and generator casings are
constructed by
welding plates into the box shapes shown at 68. The dimensions of the entire
assembly will vary
with the desired electrical output. Drum and synthetic cord assembly 69 is
shown here because it
is known as the most corrosion resistant, quietest running power transfer
system.
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Multiple cords may be necessary to transfer power in large magnitudes, and the
cord 64 is
generally constructed of high strength synthetic material. The drums 63 and 69
are sized in
diameter to give proper running speed for the generator 62. The generator
assembly is also
mounted in a plate box 61. The generator housing 61 is shaft sealed to prevent
moisture from
entering the generator assembly.
On the end of the assembly opposite that where the generator is driven, there
is a
coupling flange 73 which is keyed onto the shaft of the rotor assembly, and
allows for additional
rotor assemblies to be connected in series to the same generator. The coupling
shaft would have
a bolting pattern to match the next units coupling flange.
Operation. With reference to Figs. 2, 5 and 7, the theory of operation is and
5. In these
figures, the elementary principle of operation is visible. The base 10 is
installed in a river,
aqueduct, or fish ladder. The rotating assembly comprising generally the
spindle 22 and the
vanes 28 is mounted on the base 10. Provided the banks of the river meet with
the ends of the
hydro generator, the unit will cause a level rise on the upstream side (Fig.
7), and temporarily, a
lowering of level on the downstream side. The banks of the river must be high
enough to
accommodate the rise in river level upstream. Since this unit is designed to
be modular, having
one or more coupling flanges 73, see Fig. 5, permit the total length of the
hydro generator to be
varied to come as close as possible to the width of the river or stream.
When the water is forced to flow over the top of the unit (Fig. 7), the
current of the river
or flow energy, will sweep the buoyant, hinged vanes 28 upward and away from
the spindle 22
(Fig. 2 and Fig 7). The vanes extend outward until the butt end 40 (Fig. 2)
comes against the
spindle plate 32. At this point, the vane is held in the fully extended
position by the force of the
water against it. Once the vane of concern moves past the top center point or
"12 O'clock"
position, or the respective plate 32 is vertically outward from the spindle
shaft 22, the vane
becomes isolated from the impulse force of the rivers current, but now
experiences the
downward force exerted by the weight of the water, or potential energy.
The vanes are mounted on the spindle in a manner that promotes the best
containment of
the water between the vanes as it moves down the elevation drop. Additionally,
the end caps 53
(Fig. 5) prevent the water from running out of the edges of the vanes. The
potential energy of the
water is converted directly into rotational mechanical energy of the rotor
assembly. When the
vane of concern reaches the lower water elevation, it will discontinue adding
energy to the rotor
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assembly, but as other vanes are now at peak conversion levels, the rotor
assembly will continue
to turn. Being hinged at 30 (Fig. 2), the vane now folds back against the
spindle as it moves
around to the upstream side again.
In order to prevent large losses of potential energy from being wasted, there
is a siphon
break 54 (Fig. 3) that allows air to the ends of the rotor assembly just below
and to the
downstream side of the core shaft. This allows the water contained between the
spindle extension
plates to exit, preventing it from being sucked back around with the rotating
spindle and vanes.
The rotating rotor assembly is connected directly to the shaft 60 will be used
to drive an
electrical generator 62 (see Fig. 5). As most electrical generators are not
designed to be
immersed, it is necessary to mount the generator above the highest water
level. Since the driven
shaft is below the level of the water, the gear system or belt and pulley
system 63, 64, 69 (Fig. 5)
is provided to permit locating the generator above the water level.
In the preferred embodiment, and as shown in Fig. 5 a drum and cord type
pulley system
is use, this being free of a need for lubricants, quieter than gears, and less
likely to slip than belts.
The gears, drum and cord, or belt and pulley will all need to be kept dry. To
accomplish this,
shaft seals 62 are provided to prevent ingress of water into the pulley
compartment. The use of
the interstitial drain annulus 61, pumped by a small electric pump (not
shown), or drilled to drain
to the downstream side of the generator, will provide an extra level of
protection. The drums of
the drive shaft and the driven shaft of the electrical generator can be sized
in diameter to provide
the optimum shaft speed for the generator. The generator housing is shaft
sealed to keep out rain
and flood water.
Fig. 8 shows a system which would use the hydro-generators to retrofit a
hydroelectric
dam. The dam 80 creates a reservoir 82 on the upstream side of a flowing
waterway 84. The
illustrated example is a high head system with a dam of sufficient height to
preclude fish from
scaling the dam from the downstream 86 to the upstream side 82. The present
invention can be
used to provide a fish ladder 88 wherein a series of low head steps are
created by placing a
plurality of the hydro generator assemblies 90a,b,c...n of the present
invention in series along the
ramp 92, creating a ship ladder of the configuration illustrated in Fig. 7.
From the foregoing it can be seen that the subject invention is directed to a
hydroelectric
generator system or hydro generator having a base which is adapted to be
installed in a flowing
stream of water generally perpendicular to the flow of water for defining an
upstream side and a
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downstream side. A rotor is mounted for rotation about its axis in the base,
and a plurality of
hinged are vanes mounted to and extend radially outward from the rotor. The
vanes are designed
to open to a fully extended position on the upstream side during a portion of
rotation of the rotor
and to closed to a nested position during a portion of rotation of the rotor,
wherein the flow of
water from the upstream side to the downstream side impinges upon the vanes
and opens them to
the fully extended position to drive the rotor. The rotor or the rotor and
vanes may be
completely submerged.
In the preferred embodiment, the base includes a vane receptive channel for
receiving and
collapsing the vanes into a nested, closed position during the portion of the
rotor rotation cycle
wherein selective of the vanes are in communication with the channel.
Typically, the base
includes an upstream wall and a downstream wall and wherein the upstream wall
is higher than
the downstream wall.
Preferably, the rotor extends the span of the waterway and the vanes extend
the length of
the rotor. The rotor may include a positive stop for defining the fully
extended position of the
vanes. End caps, mounted on either the rotor or the vase define a closed
cavity between adjacent
vanes. Preferably, each vane is concave curved relative to the upstream side.
A siphon drain may be included between the upstream side and the downstream
side of
the base.
An electric generator is provided and a drive shaft for driving the generator
is driven by
the rotation of the rotor.
In operation, the base and rotor are submerged in a running stream of water,
with the
rotor horizontally mounted, with a plurality of hinged vanes which open to
catch the water as it
runs over the top, hold the water as it is lowered during rotation, release
the water when it is
lowered a predetermined amount, and close to allow for submersed rotation with
minimal losses.
One useful application of the invention provides for the retrofitting of high
head dams to
create a ship ladder downstream of the dam where each step of the fish ladder
is created by a
submersible hydro generator. The fish ladder to allow for the entire flow
capacity of the river.
While certain embodiments and features of the invention have been described in
detail
herein, it should be readily understood that the invention encompasses all
improvements,
modifications and enhancements within the scope and spirit of the following
claims.
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