548 CEMENTS, LIMES, AND PLASTERS. 



Storage, Packing, and Market. 



Necessity for storage. A twofold necessity exists for large storage 

 space at a modern cement-giant. The cement will in many cases 

 be improved by storage, particularly if it can be so stored that air will 

 gain access to the mass. Aeration in the storage building is, however, 

 rarely possible; and in consequence the tendency now is in the direction 

 of aerating or slaking the clinker before grinding. The main reason 

 for storage still remains prominent. It is caused by the fact that while 

 the average mill runs twelve months in a year, the cement-selling period, 

 in most of the United States, is practically confined to six months or 

 even less. This of course necessitates very extensive storage facilities 

 enough to hold at least three months' output of the mill, and preferably 

 to hold six months' production. This means that for each kiln in a dry- 

 process plant, storage space for at least 20,000 barrels should be provided. 

 As Portland cement dumped from a conveyor will pile up so as to 

 weigh about 90 to 100 Ibs. per cubic foot, the storage space above stated 

 (20,000 barrels) would be equivalent to about 80,000 cubic feet for each 

 kiln in the plant. This is the minimum of space that can be given with 

 safety, and an allowance of 150,000 cubic feet per kiln would be much 

 better for the average plant in the Middle or Eastern States. In the 

 South and West conditions are different, and much less storage space is 

 required. 



Designs of storage buildings and bins. In Figs. 139, 140, 141, and 

 142 are given plans of several recently erected storage buildings and 

 bins. Those shown in Fig. 139 are concrete-steel bins erected for the 

 Portland-cement plant of the Illinois Steel Co. 



The stock-house and bins shown in Figs. 140, 141, and 142 are those 

 of the Hudson Portland Cement Co. In a description of that plant 

 accompanying these figures * the following data are given: "The stock- 

 house is a structure 410 feet long and 105 feet wide, having as founda- 

 tions a series of concrete walls founded on piles. It contains three groups 

 of twenty bins each. The bins are of wood, their walls being laid up 

 solid of 2"X10" and 2"X8" plank laid flat and spiked together. The 

 total capacity of the bins is 200,000 barrels of cement. Cement is con- 

 veyed to the stock-house from the mill by means of conveyor 26, which 

 discharges into the boot of elevator 0. This elevator discharges into 

 the transverse screw conveyor 27, which spouts onto two belt conveyors 



* Engineering News. 



