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The Pressure Wheel
Dennis P. Buller

Background
Five years ago I was studying the History of Technology at the University of
Connecticut, where I became involved in the study of waterpower. I found it
fascinating that almost all of the power that human beings had at their disposal up
until the turn of the last century was waterpower. It was a very decentralized
power system, consisting of direct mechanical power that ran the factories and
mills that turned out lumber, iron, and the mass-produced goods of the time.
With the advent of electricity, the building of large dams, and the increased cost of
labor, it became impractical for factories to each have their own source of power.
The mills closed due to their inability to compete with larger factories. Whereas
our economy had been driven by the small-scale production of hydropower on
almost all small and mid-sized rivers, it came to rely upon large dams that were
able to generate massive amounts of power inexpensively. Inexpensive power
allowed our economy to expand and promoted the development of communities
that had power at their disposal, which brought about great improvements to our
civilization and people’s lives.
The problems with this situation arose when people started to understand the
ecological problems that large dams cause. The plight of the salmon was the main
issue in addition to the over-oxidization of the water flowing over the dam and the
holding of sediment behind the dam. Today, there is no political will to build new
large dams. Waterpower as we know it in the United Stated is not expanding and
there is a great deal of pressure to take down dams that are creating
disproportionate environmental damage in comparison to their power output.
I originally started working with hydropower with the intent to make a inexpensive,
simple-to-build overshot waterwheel. After creating such a wheel, I was
dissatisfied with its complexity. I also found that few people had the required head
(water fall) for an overshot wheel to operate. Thus, I started looking for a design
that would allow people to harness the power of rivers without a dam or head.
In researching the technology already available, I became disappointed. The best
large-scale designs were the “underwater windmills.” They are complicated,
expensive, and, worst of all, underwater. That makes completing maintenance
difficult. If something goes truly wrong, the whole system must be pulled out of the
water to be repaired. The cost and engineering of a large underwater power plant
that must be secured to the river or ocean floor are too great.

The Problem
The main problem with creating power from a river is speed. The river’s slow
speed makes it necessary to either employ a large generator that makes power at
very low RPMs or an expensive transmission that wastes power. Both of these
methods would make the creation of power from a river economically impractical.

The Solution
My vision for a new type of hydropower is what I call the pressure wheel. I started
looking for the perfect design to capture power out of large rivers and found the
basic principles of a new system online at http://aquamor.tripod.com/page4.html
and at http://www.lurkertech.com/chris/eco/pump/tailer/. The wheels on these web
pages are small, made of wood, and are being used to lift water for irrigation. So,
even though these designs are not the solution, I found that the spiral pumps
being used to lift the water have some amazing characteristics.

Characteristics of the Spiral Pump
1. The spiral pump creates multiple small columns of water, which has the net
effect of being one large column of water.
2. Due to this, the spiral pump changes high volume, low-pressure water (the flow
of the river) into low volume, high-pressure water (in the spirals).
3.As the spiral pump creates more pressure, the wheel to which it is attached
slows. This in turn increases the difference in river speed to wheel speed,
meaning that the slower the wheel goes, the more power it garners from the river.

How the Pressure Wheel Works
I have taken the spiral pump and its unusual characteristics and added new
components to it in order to create electricity. The fluid the pump uses is not taken
from the river like in the web sites, but is part of an enclosed system. The fluid is
taken from a holding tank on the side of the wheel, using a scoop. After the fluid
goes though the spiral pump, it goes into a separator tank. The tank allows air to
exit the system when the fluid level gets too low. This regulates the system to a
certain pressure at all times. It does have the drawback of capping the pressure in
correlation to the percentage of air in the spirals, but if higher pressure is required,
more spirals can be added. The pressurized fluid will then be run through a
turbine, creating electricity. Finally, the fluid will be gravity-fed back into the scoop
reservoir to start the process all over again.
This system can be used with overshot, undershot, and breast wheels. Overshot
wheels are the most efficient of the three, but a dam or natural head is required. I
foresee large undershot wheels on the ocean making the most inexpensive power
due to the limitless size. Tide wheels are also very viable; the design can be
configured to make power in both directions. However, river wheels will be easier
to start with since they will be smaller. We can select spots that have rapid flow
and will be located close to where the power is needed, such as towns and cities.

Future Directions
In the near future I see large pressure wheels harnessing the power of our small,
medium, and large rivers, oceans, and the tidal flows of our bays. The system will
ride on top of the water, floating. It will be tethered to the bank(s) of the river by
way of cable, or to the ocean floor. It will be made of PVC pipe in the smaller
versions and ceramic-coated iron pipe in the larger versions. Because it is an
enclosed system, the pressure wheel does not require that the fluid be freshwater.
Saltwater or another environmentally friendly liquid that will not freeze in cold
weather climates could also be used.
The pressure from the spiral pump can be changed by either making a few large
spirals (lower pressure, higher volume) or using a large number of smaller spirals
(higher pressure, lower volume). Since the costliest part of the project will be the
turbine and generator, I foresee us making a great deal of pressure with lower
volume, and running it through a small turbine with a heavy-duty generator.
Safety is a concern with putting these large wheels on the river. They will have a
safety net on each side to keep small boats and people from being able to enter
into the paddles. The paddles will actually be going much slower than the river so
there is no concern for people being “sucked into” the wheel. In addition, blinking
lights will be attached to each side of the front and back of the wheel to alert craft
of the wheel’s position. For smaller rivers, on which there are no kayaks or
canoeists, the entire power of the river can be harnessed over and over again in
multiple spots, providing inexpensive, continuous, decentralized power for
communities. This decentralized power will have the advantage of low line loss
and continuous production with incremental change. For large rivers with boating
traffic or smaller rivers on which there are kayaks and canoeists, a percentage of
the river can be used. For oceans, once we go far enough out, there is no limit to
the size or power that we can harness.
Furthermore, environmentally-sensitive spots can be avoided. The wheels will
slow the river down and may raise the water level behind them a couple of inches.
This must also be taken into account. Fortunately, with this design, the river is not
separated at any point so that fish and other wildlife will have no problems
traversing the slow movement of the paddles.

Economic Considerations
No alternative energy plan will work unless it makes inexpensive energy. For all
the talk of saving the environment, if you ask most people to choose between a
cheap electric bill, or an environmentally friendly but expensive bill, most will find it
more important to save money. Our task is to make these wheels as economical
as possible. Labor is the biggest expense most companies have. With this in mind,
let’s look at the construction of a large pressure wheel.
The wheel and the frame will be made of ceramic-coated iron pipe. Iron pipe is
inexpensive, and the machines to thread the ends and bend them into shape are
readily available. Ceramic coating is incredibly hard, comes in a variety of bright
colors, and most importantly, makes the pipe rustproof and visually appealing. The
iron pipe will thread together to make the frame and the wheel. This will allow a
semi-skilled labor force to put them together. The pieces will be redundant, making
manufacturing easy. The frame and wheel will ride on plastic dock pontoons. They
are inexpensive, sturdy, easy to work with, and last a long time. The spiral pump
will be made of off-the-shelf heavy plastic pipe or ceramic-coated iron pipe. The
width and length of the spirals will be determined by the size of the wheel, average
flow rate of the river, and pressure required for the selected turbine. I see the
manufacturing of these wheels being done at one location in the country. From
there, kits would be sent out to local contractors for assembly on-site. Another
alternative would be to dispatch small crews from the factory to take charge of the
assembly.
What I want to stress about this design is its simplicity. The wheel itself will have
two bearings; the turbine will have two bearings; and the spiral pump will have a
rotating connector. Since this design has so few wearable parts, it is inexpensive
to make those parts extremely strong and have them last a very long time. The
use of bearings that are twice the size needed and made of stainless steel are well
within cost. This would provide guaranteed operation without emergency
maintenance throughout the life of the assembly, which would be about twenty
years. This is important in the sense that one or a few maintenance personnel
checking and greasing the system on a quarterly basis is much less expensive
than having large crews performing emergency repairs. In addition, the design is
simple enough that the amount of money being spent on maintenance will be at a
minimum. Once the pressure wheels are up and running, they shall continue to run
until the whole system is pulled out and another is put in its place.
The pressure wheel is the right design for this era of power. It gives control of
power production to local companies and politicians. It has the characteristics of
being highly economical, environmentally friendly, simple, and pleasing to the eye.
It also has the ability to coexist with people using the river for recreation and
business. I look forward to creating a large-scale model and sharing with the world
this innovative technology that draws upon an early, simple idea to help serve
modern-day needs.