CEMENT BURNING: FIXED KILNS. 



477 



which is the principal defect encountered in running a vertical kiln 

 continuously. 



FIG. 113. Hauenschild kiln. 



Schwarz kiln. In a recent paper on the manufacture of Portland 

 cement from a mixture of slag and limestone C. von Schwarz describes 

 a kiln used at a German cement plant. This 

 kiln, here called the Schwarz kiln, is shown in 

 partial section in Fig. 114. It is described as 

 follows : 



Each kiln consists, in its essential part of a 

 series of rings, each 1 inch to 1 inches in thick- 

 ness, 83- feet inner diameter, and 18 inches in 

 height. These rings are provided outside with 

 ribs, r, Fig. 112, and placed in such a way, one 

 above the other, that the vertical ribs cover one 

 another, thus forming little vertical channels 

 c, c, c all around, in which the air circulates 

 from below to the top, like in a chimney, thus 

 continually cooling the cast-iron rings from the K- SECTION 



outside, and preventing them from getting over- FIG. 114. Partial plan 

 i . , r -i i i , T and section of Schwarz 



heated. The materials to be burnt are in direct kiln (Engineering 



contact with the cast-iron rings, no lining of any News). 



kind being provided for. There are 18 such rings, put one above the 



