CLINKER COOLING, GRINDING, AND STORAGE. 529 



with water. The elevator dumps the clinker into a cooler built by Wm. 

 F. Mosser & Son. There are three of these coolers, each 32 feet high, 

 8 feet in diameter, having a cast-iron blast-pipe running through the 

 center, with sheet-steel conical shields every 5 feet, extending to within 

 10 inches of the shell of the cooler. 



"Under this shield are holes in the blast-pipe, through which a 

 constant flow of fresh air is maintained by means of a fan, the air 

 passing out of the cooler through holes in its shell the latter having 

 conical shields on the inside just above these openings. 



"The heat of the clinker is absorbed in the vaporization of the 

 water and is removed by the current of air which passes through the 

 thin stream of clinker moving through the cooler between the two shields. 



"The coolers rest on a cast-iron plate, supported by foundations 

 4 feet high, in a pit about 20 feet below the kiln-room floor. Running 

 under these coolers are belt conveyors which receive the cooled clinker 

 (drawn from four openings in each cooler) and carry it to the boot of 

 an elevator, which discharges it through an opening in the wall between 

 the kiln room and the clinker ball-mill department onto a storage floor." 



One-stage rotary cooler. The next step in clinker-cooling devices 

 is the use of rotary coolers. These are simply rotary driers, reversed 

 in action, and require no special description here. 



Atlas two-stage rotary cooler. By far the most satisfactory of cool- 

 ing devices is the two-stage rotary cooler employed by the Atlas Port- 

 land Cement Company. It is, so far as the writer knows, the only 

 cooling system which really cools the clinker to a handling temperature 

 and does so quickly and economically. 



The cooling system at the main Atlas plant was described by 

 Stanger and Blount in 1901 as follows: 



"The clinker drops from the burning cylinder into a second rotating 

 cylinder, about 30 feet long and 3 feet in diameter, revolving about 

 six times as fast as the burning cylinder. This is lined with fire-brick, 

 and through it passes a current of air which goes to feed the flame of 

 burning coal-dust. The greater part of the sensible heat in the clinker 

 is thus saved and utilized. The clinker, still moderately hot, falls on 

 to three crushing rolls contained in a housing and moistened by a spray 

 of water. As shown in the figure a pair of kilns with their accompany- 

 ing first cooling cylinders converge so as to deliver the clinker onto 

 these rolls and from this point a single secondary cooling apparatus 

 serves this pair of kilns. The object of the rolls is to crush large lumps 

 of clinker which may have been formed by the aggregation of a num- 

 ber of small fragments adhering together when plastic in the burning 



