. The miller, millwright and millfurnisher. ouble from stoppages for repairs. There isan excessive amount of friction by reason of their great weight, and theyare not well adapted for use where the water level varies. In this respectthe breast wheel is better, as there can be two or more gates to accommodatedifferent levels. Overshot wheels are more economical, proportionally, atpart gate than turbines. They are slow moving and for most manufacturingpurposes require too much gearing up to get speed. A 24-foot wheel should * Detailed instructions for building wooden water-wheels are given in tl
. The miller, millwright and millfurnisher. ouble from stoppages for repairs. There isan excessive amount of friction by reason of their great weight, and theyare not well adapted for use where the water level varies. In this respectthe breast wheel is better, as there can be two or more gates to accommodatedifferent levels. Overshot wheels are more economical, proportionally, atpart gate than turbines. They are slow moving and for most manufacturingpurposes require too much gearing up to get speed. A 24-foot wheel should * Detailed instructions for building wooden water-wheels are given in tlie chapters on Millwrighting. 78 WATER-WHEELS WITH HORIZONTAL AXES. make about four turns per minute. The fall is the distance between thesurfaces of the water in the head race and the tail race. In overshot wheels,throughout that portion of the distance between the surface in the head raceand the wheel itself, it acts by impulse only and not by weight. The fulloutside diameter of tlie wlieel does not have useful effect, liut there is some. Fig. 33. — Overshot Wheel. loss both above and below, say one-half of the depth of two buckets, equalto the depth of one bucket. Vertical Wheels vs. Turbines.—Vertical wheels (that is, wheelswith horizontal axes; gencrnlly cost more to erect than turbines, except forlow falls. Vertical wheels are. very much impeded by ice forming, while DIFFERENT KINDS OF WHEELS, ETC. 79 turbines are not ; back water interferes with them seriously, and they aremore difficult to erect than turbines. In all wheels there is loss byreason of the space between the wheel and gate; some by friction in gateand buckets and journal friction. The Largest Water-Wheel.—One of the largest water-wheels inthe country is the overshot which runs the Cascade mill at Akron, Ohio. Itis 30 feet diameter by 10 feet face ; but one much larger is that shown inFig. 7^7,, and which is over 50 feet in diameter. This is used to drivethe factory of the New York Belting and P
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectflourmi, bookyear1882
