326 ‘ ANNUAL REPORT 
chemist allows the cement in such a bin to be shipped, keeping a record 
of the tests made. ‘Theoretically, of course, the cement should be kept 
stored in thin layers to which the air has ready access, but in practice this is 
difficult to carry out. The bins should have a sloped bottom so that 
the cement can be discharged by gravity by simply lifting a slide. The 
packing is usually done at one end of the stock house. In regard to 
the use of packing machines opinions seem to differ, some advocate them, 
others think hand packing is just as cheap. [Evidently the amount saved, 
by using machines, if there is any saving, is quite small. Sacks are used 
mostly at present in place of the barrels which were employed almost 
exclusively a few years ago. 
The net weight of cement in barrels varies somewhat according to 
whether the cement is packed or 1s loose. S. E. Thompson found the 
net weights of cement per barrel to vary from 370.07 to 387.0 pounds. 
A cubic foot of various Portland cements, packed and loose, was weighed 
and found to weigh as follows: 
Packed Loose 
pounds. pounds. 
(GIATIE ae sens Boy ne OR hey oA ie ae ee 113.81 91.38 
val (20 geome Matt et ae a Re os ei Bs aL Pec 118.45 89.20 
MEWS oa odo noc Ree MY tn nicks 122.75 94.24 
Dy ckerhoths anes on eee 123.16 93.18 
PAG aS asics aes) ae A ie aN pee 117.54 100.49 
SANDOR ey oe aa hues ee eo yrebor mera HAS) 71 91.40 
The barrels weigh from 21 to 25 pounds. Each barrel is supposed to 
contain 380 pounds of cement, each sack 95 pounds. 
Power Required in Cement Works.—A good basis for estimating» 
the power required is afforded by the figures, already quoted, in part, 
which represent the power required at thé cement works of Wm. Krause 
and Sons, Martin’s Creek, Pa., as determined by actual measurement from 
the input and output of the electric motors used. The friction load of 
the plant, main shaft 6 inches in diameter and 240 feet long, is 55 horse- 
power. Power to drive 4 ball-mills is 155 H. P. or per mill 39 H. P. 
Five tube-mills use 333 H. P. or 66.6 H. P. per mill. 
Each kiln, one revolution per minute, uses 3.7 H. P. A 30 foot belt 
conveyor for stone, 1.2 H. P. 
A stone crusher of a capacity of 25 tons per hour, with its bucket 
conveyor, 32.6 H. P., maximum load. | 
“Stock house, screw conveyors 450 feet long, 2 barrel conveyors, 
packers and shafting, 19.5 H. P. 
Each figure represents the output of the motor for the purpose 
designated. 
A conyenient rule for estimating the power required in cement imills 
is: One H. P. for each barrel produced per day if marl is used and 1.5 
H. P. per barrel per day if rock is worked. 
