508 CEMENTS, LIMES, AND PLASTERS. 



In regard to Richards' results it may be said that the use of such 

 a large excess of air is not normal practice, either in the Lehigh district 

 in general or at the Dexter plant in particular. It is further doubtful 

 whether a kiln run so wastefully as this one appears to have been could 

 make good cement with a fuel consumption as low as 110 Ibs per barrel. 

 These questions throw doubt on the calculated loss of heat in the waste 

 gases. The amount allowed for dissociation of the carbonates is appar- 

 ently only about one-tenth of what should be allowed, owing to an 

 arithmetical error. When this error is corrected, the "loss of heat by 

 radiation" is made a minus quantity. In Table 193 below, this cor- 

 rection has been made, but Richards' estimates as to waste gases are 

 left unchanged. 



Carpenter's tests. Prof. R. C. Carpenter tested two rotary kilns 

 at the plant of the Cayuga Portland Cement Company, near Ithaca, N. Y. 

 The test was made primarily to determine the efficiency, not of the 

 kilns, but of a boiler designed to utilize their waste heat. 



The coal used in the kilns was Westmoreland (Pa.) slack of the 

 following composition and heating value. 



Moisture 2 . 19 



Volatile matter 32 .9 



Fixed carbon 54.66 



Ash 10 . 25 



B.T.U. per pound 14,022 



At the time of test the two kilns were taking together 1889 Ibs. 

 coal per hour, producing 21.2 barrels of clinker, equal to a coal con- 

 sumption of 89.1 Ibs. per barrel. This low fuel consumption is attained 

 in part by the use of waste heat from the clinker as shown in the table 

 below. 



Carpenter's paper, as originally published, contained a number of 

 serious typographic errors, which the author has kindly corrected on 

 the copy sent to me. In the table below I have therefore made use 

 of these corrected results, so that the second column of this table 

 (193) will be found to differ considerably from that given in the 

 original. 



It will be seen that Richards' results, when corrected for the carbon- 

 ate requirements, leave no room for radiation losses. 



For my own detailed estimates on most of these points, the 

 reader is referred back to pages 498, 501. 





