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190 VARIOUS MECHANICAL APPLIANCES.
Experiments at the Empire Mill.—An
experiment at the Empire Mill, French Corral, was made under the
following circumstances, giving the annexed results: Ten stamps, weight
of each 693-1/4 pounds. Drop, 0.768 feet. Speed of stamps, 62.2 drops
per minute. Work done by 91.68 cubic feet of water per minute head,
130.1 feet. Size of wheel, 13^ feet outer diameter. Diameter of wheel,
12.58 feet to centres of buckets. Size of buckets, 4 inches wide and 6
inches deep, set 10 inches apart. Water conducted to wheel through an
11-inch pipe 866 feet long. The wheel was direct on the cam shaft;
single cams used. The mill crushed 60 tons of gravel in 24 hours ;
one-quarter-inch screens were used.
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The
head at French Corral was the height of the water in pen-stock above
the nozzle, no allowance being made (as in the North Bloomfield
experiments) for the loss of head by friction in pipes and by leakage.*
Curved Buckets.—Recent patterns of wheels with curved buckets have given an efficiency very much in excess of that described above.
Tests at the Idaho Mine.—A series of comparative tests was made in the spring of 1883 at the Idaho Mine,
*
All the data given on pages 189 and 190 concerning Hurdy-gurdy wheels
were communicated by the author to the American Institute of Mining
Engineers in a paper read at the Wilkesbarre meeting, May, 1877. See
vol. vi. " Trans. Amer. Inst. Mining Engineers."
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