CANE SUGAR. 



Saturation Processes. Let canes containing / fibre be crushed 

 till the megass contains m fibre, and to the resulting megass let w water be 



added, the water mixing completely with the residual juice in the megass. 



/ / + w m -> 



The weight of the megass and added water now is + w =: - 



and the residual juice in the megass being - - - , the weight of the 



diluted juice i8 /(/ rc* + w = f+-f m ; If this saturated megass be 



crushed until it again contains m fibre per unit weight of megass, the weight 



f -\-wm- fm wm T _ . , 



of diluted juice obtained is w -i- - ^ - = , wm _f m If 1Q stead 



of crushing the saturated megass to m fibre, it be crushed to m 1 then the pro- 



. m 1 (/+ wm) fm 

 portion of juice obtained of that originally present is t , wm \ _ f m 



The use of this method of calculation permits the different schemes for 

 applying water in saturation processes to be critically examined. 



Single Saturation. By this term is meant a process where the canes, 

 after dry crushing, are saturated once with water and again crushed. In 

 the annexed table is calculated, on the lines developed above, the extraction 

 due to saturation, and the total extraction on the understanding that the megass 

 contains 45 per cent, fibre in the dry crushing, and 50 per cent, in the saturated 

 crushing. 



The added water is assumed to mix completely with the residual juice and 

 the latter is taken as having a sugar value equal to *85 of the juice obtained 

 in the dry crushing. 



It follows as a result of the equation, and as can be seen from inspection 

 of the table on page 209, that as the quantity of added water increases, the 

 proportionate quantity of sugar obtained due to saturation rapidly decreases ; 

 further, as the proportion of fibre in the cane increases, the part extracted due 

 to saturation increases also, so that with high fibre in cane, it is of greater 

 importance to carefully oversee the admixture of the added water, and to 

 control as far as possible the fibre in the raw material entering the mill. 



Double Saturation. By this term is meant a process in which the 

 water is added in two portions, in the case of a nine-roller mill partly after 

 the first, and partly after the second mill ; in general such a scheme is not 

 attended with very material benefit with the nine-roller mill, since the megass 

 coming from the first mill is not in general sufficiently well crushed to absorb 

 the added water. In a twelve-roller mill, however, material benefit follows 

 by adding the water in part behind the second, and in part behind the third 

 mill. In the case of a cane containing 10 per cent, of fibre dry crushed to 

 45 per cent, of fibre, and then after the addition of 10 per cent, of water with 

 complete admixture, and crushing to 50 per cent, of fibre, an extraction of 



208 



