449
OF ENGINEERING FOBMULÆ.
Winding Engines— continued.
To find the diameter of the winding barrel foi
flat ropes :—■
P = Depth of pit in feet.
R = Number of revolutions of engine.
T = Thickness of rope in inches.
D = Diameter of winding barrel in feet.
12P-3-15R2T
D “ 37 TB
Mining Machinery.
Speed of crushing rolls atl
periphery.......... /
Diameter of ditto ditto ..
Breadth of ditto .. ..
Roller shaft ..
Tumbling shaft ..........
Sifting screen shaft .. ..
Rolls crushed together with a
Weight of stamper heads from
Lift of ditto .. .. .. ..
60 feet per min.
24 to 30*inches.
12 to 15 „
6 inches square.
4| „
lj inch diam.
force of 60 tons.
IJ to 5 cwt.
9 to 12 inches.
Number of lifts per minute .. 45 to 60
Exposed area of cast gratings j 9„ x ß incheg_
about .. .. .. J
Number of holes to the inch)
for ti,n.......... • • /
Area of stamper bottom gene- j g x 10 inches
rally.................... / '
Pumps for deep mines, usually 8 to 10 ft. stroke.
Each lift ..........fr°m 150 to 200 feet.
Horse-power of Pumping Engines.
Q = Quantity of water raised per minute, cub. ft.
H - Height in feet.
Actual horse-power = ‘ 0023 H Q.
2 &
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