THE EXTRACTION OF THE JUICE BY MILLS 



237 



hard to obtain, but the following from the writer's notebook is of interest. 

 The data were obtained following the breakdown of one unit of a four-mill 

 and crusher train, reducing the combination to a three-mill and crusher 

 installation. The periods compared are each of three weeks' duration,. 

 and by a happy coincidence the tonnage ground and the fibre in the cane 

 are nearly the same. 



Purity 

 first mill 



juice. 



Crusher and three mills 91-1 

 Crusher and four mills 91-7 



Purity 



last mill 



juice. 



80-7 



81-3 



Purity 

 mixed 

 juice. 

 87-0 

 88-2 



Tons 



cane 



per hour. 



Fibre 

 % 



cane. 

 13-8 

 13-9 



Dilution 



% normal Extraction 

 juice. 



27-0 92-35 

 22-1 95*56 



As affording a conspectus of the combined effect of fibre and methods,. 

 values of the recoveries under the above-developed expressions are given 

 in the annexed table for values of /o 10 to o 15, of w o 10 to o 30 and m o 50. 

 This table is academic rather than representative of results of record, since 

 in its construction complete admixture of the added water is assumed. 

 Its object is to give a perspective view of the effect of the different controlling 

 factors. It neglects two sources of error : i. The recovery due to the dry 

 crushing is always greater than the calculation implies due to the superior 

 quality of the first-expressed juice. 2. Admixture of the added diluent 

 with the residual juice is never complete. To a certain extent these influ- 

 ences are compensatory. 



TABLE GIVING COMPUTED EXTRACTIONS IN DIFFERENT SYSTEMS OF MILLING FOR 

 VALUES OF FIBRE 10 TO 15 PER CENT. ON CANE, ADDED WATER 10 TO 30 PER CENT. ON 

 CANE, FIBRE IN BAGASSE 50 PER CENT. VALUES REFERRED TO SUGAR IN CANE AS 

 UNITY. 



