543 OK ENGINEERING FOBMULÆ.
Hydkaumc Pbess.
D = External diameter of press in inches.
d — Internal „ »> >•
P = Working pressure of press, tons per square inch.
S — Safe working stress on metal, tons per square inch.
Hyp. log. ~ • D = d x.
CL ö
Values of x.
II II Ph 1» ft S •a 1-23 •3 1-35 •4 1'49 •5 1-65 •6 1-82 •7 2-01 •8 2-23
II II P-, Ice a 8 •9 2*46 1-0 2-72 1-1 3-01 1-2 3-32 1’3 3-67 1-4 4-06 1-5 4-48
Assuming safe working stress of cast iron = li tons per
square inch, the following are the values of x:
Working Pressure, Tons per Square Inch.
P as x = | -5 1 -6 I -1 | -8 jl-4 |1-49'1'6 |1’71 •9 1-82 1-0 1-95 1-25 l-5ojl-75 2-00 2-3 |2-72|3-21|3-79
Hydraulic Machinery.
Tweddell in his hydraulic riveting machines uses pressures
varying from 1000 to 1750 lbs. per square inch (say from
•45 to 78 ton per square inch).
The accumulator is supplied by two pumps, 3-inch stroke,
each If diameter, making from 100 to 12o revolutions per
minute. Armstrong uses for crane work a pressure of
700 lbs. per square Inch (say -3125 ton).
Hydraulic Machines (Toülon Dockyakd).
(‘ Min. Inst. Meeh. Engrs.,’ 187s.)
Machine. Diam. Kam. Area. Stroke Pres- sure. Daily WorklO hrs
Strokes. Water.
ins. ins. ins. tons. cub. ft
Plate punching 9-93 77-5 3-15 49’21 1200 188
Ditto „ 14-05 155 3-94 98’42 600 235
| iron shearing 12-17 116-25 6-69 73-81 400 200
Ditto „ 17-21 232-5 945 147-63 200 282
Plate flanging Channel iron ( 15-30 186 13’78 118-10 SO 82
9-93 77-5 11-81 49-21 200 118
bending .. 1 14-05 155 11-81 f»R-42 100 118