Design of a Waterwheelfor the Botanical Garden
Design of a Waterwheel
From "Campus Observer", 1/28/2004
Summary
A small water wheel provides an educational experience in the availability of hydroenergy from a relatively small stream that I shall name "Dent Creek" in honor of Dent Smith, who developed the gardens and stream. (Upstream, it's known as the "Dartmouth Ditch", and is just south of the homes on Dartmouth Ave.) This wooden, multi-blade, horizontal wheel is equipped with an extended shaft carrying a "V"-belt wooden pulley. When needed for a student or class demonstration, a "V" belt can be slipped over an added pulley to drive an experimental device. A prototype wheel was installed June 1st, 2004. That night, a severe thunderstorm occurred, dumping some 1.5 inches of rain and raising the stream. The wheel survived but moved the supports back slightly. The wheel has been repositioned, the anchoring strengthened, a trash diverter added, and the location optimized. Note that a modest flow results in some 50 rpm rotation.
The actual appearance of the area is in these photos. THe photo above shows the wheel before the generator was added. Here's an assessment, the stream hydrology, and a teacher's guide.
Concept and Local History
The restoration of Florida Tech's Botanical Gardens incorporates a bit of nostalgia in the form of a cypress-wood waterwheel at the existing waterfall. The views of the pool and waterfall may be seen in the photos.
The wheel turns at slow speed, and its rotation and splashing adds an interesting feature for the amusement and consideration of those pausing nearby. There is, of course, a renewable energy demonstration present here, with an educational outreach designed to attract local students in the science and technology of many years ago. Motion is always an exciting aspect of science.
In Brevard County history, plentiful artesian water led to the construction of many of these wheels. Some of you may remember a water wheel near Floridana Beach at a motel and the five-foot diameter wheel at the old Mather's Bridge Restaurant. The restaurant owner had constructed the wheel to run a generator to provide electric lighting. From the "Eau Gallie Hiking Tour", "In 1902, the novelty works and planing mill of the East Coast Lumber and Supply Co. were located here. Its water wheel was powered by an artesian well, and the electricity produced here was also used in company president George F. Paddison's house, located six blocks to the south." --http://www.geocities.com/yosemite/rapids/8428/hikeplans/eau_gallie/planeaugallie.html.
Weona Cleveland, local historian, writes about the Melbourne Beach Power Plant, "A 12-foot artesian well was drilled in 1888, and its pressure was used to push a water wheel. That water wheel was used to run a power plant, built here in 1915 for $8,000."
http://www.geocities.com/yosemite/rapids/8428/hikeplans/melbourne_beach/planmelbeach.html.
(I suspect that might be a 12-inch well.)
In Grant, more sophisticated turbines were produced by the Couch Pump Company to run on artesian wells and drive a generator. There is also history here of mechanical power: "The hotel [former Goode House] was bought by C. J. F. Campbell, who enlarged it to be the Bellevue Hotel. It had a cement pool and a water wheel and pulley carried the guests' luggage to the third floor. In 1920 it was renamed as the Orange Spot Inn, owned by Harry Balsley of Detroit." -- The Crane Creek Hiking Guide, http://www.geocities.com/yosemite/rapids/8428/hikeplans/crane_creek/plancranecrk.html.
Florida Tech has a free-flowing drainage stream from west of Country Club Road, thus it contains educational aspects of meteorology, hydrology and fluid mechanics. I designed a waterwheel approximately two feet wide and two feet in diameter and installed it to provide a V-belt pulley drive on the west end of the support shaft. This wheel will provide the turning power to any student project with the proper size belt. For example, student projects might measure the torque as a function of pool height, generate electricity for power measurements, or simply drive some mechanical device as an indication of available energy. When the student project is removed, there is only the simple pulley remaining for future use.
The Existing Waterfall
The irregular spillway is formed of coquina rock that extends some 17 inches upstream. The actual overflow is quite level, suggesting early grinding to even the water flow across the spillway.
The flow over the dam is about 0.25-1.0 inch in dry weather and perhaps 2 to 6 inches in rainy weather. In severe storms, the height may exceed 8 inches. The height of the wall cannot be increased as the walkways upstream would be flooded. There is significant impoundment for at least 100 feet upstream, providing averaging of the incoming flow. In large storms, the stream overflows the pool walls and the banks upstream and bypasses many bends to flow over land.
Hydrology and Stream Flow Characteristics
The flow will vary strongly with rainfall, and since the drained neighborhood area is small, there only about 15 minutes delay in increased stream flow after rainfall begins. Then flooding begins.
Waterwheel Architectural Design
An assessment of the water flow was necessary to plan the details. Here is a PowerPoint presentation on the project.
A relatively simple wheel was constructed of two-foot cedar boards and deck screws. We (team of Bill Battin, Matt Tanguay, and Frank Leslie) used cedar fence boards. A 3/4-inch steel pipe shaft supports the wheel and passes through two PVC bearings. Pillars would be used to support the bearings and resist over-turning, but initially, wood 2x4s will do. A closed-end design allows the water to fill the buckets thus formed on the side towards the pool spillway. This weight of water forces the wheel around (down on the north side), as opposed to fast-flowing water that uses kinetic energy to turn a wheel. The initial installation measured 60 revolutions per minute.
The edge of the spillway was not straight in the horizontal, and some minor chipping of the downstream end was done to make the water flow more evenly on the western two feet. A temporary paver dam about 1.5 inch high will be placed on the eastern end of the spillway to divert the flow into the wheel. If satisfactory, a layer of concrete paver blocks would be substituted by cementing in place or a simple layer of grout. In flood flow conditions, the water will overflow these blocks or grout to allow the excess water to pass downstream.
The supporting wood structure is fixed in the channel to hold the wheel in place during flood conditions. This area has reportedly been underwater in hurricane storms. Eventually, the mounting may be built more strongly to prevent the wheel from moving away. So far, no direct attachment has been made to the spillway wall.
Some Potential Demonstration Projects
Local science students could use this water-powered hydrodrive to turn devices that they have created. Homemade generators, conveyors, or artwork come to mind. A Teacher's Guide to Waterwheels is here.
The shaft pipe is closed with 3/4-inch pipe caps. We plan to have a 5/8-inch steel shaft welded to a cap to mount the V-belt pulley. The other end cap will have a 6-inch pipe "crank" so it can drive something with an oscillating motion like a temporary saw or artwork mobile.
Also see http://www.angelfire.com/journal/millbuilder/historical.html and http://scholar.lib.vt.edu/mirrors/vaes/99-1-2.pdf for history.
Water pumping using a coiled pipe in the wheel. http://aquamor.tripod.com/Wheel.htm
Other Florida waterwheels (off site)
Back to Frank Leslie's home page
www.fit.edu/~fleslie/Conventional/waterwheel.htm updated 050301
