THE EXTRACTION OF JUICE BY MILLS. 



of megass may be used in addition to the one throwing water on to the upper 

 surface.* 



3. To enable the megass to absorb water readily, it must be finely 

 crushed ; generally first crushing megass is not fine enough to readily absorb 

 water. 



4. A greater recovery is obtained when the diluent is used in two portions ; 

 this is sometimes referred to as double maceration. 



5. As the mixture of juice and water is not instantaneous, as much time 

 as possible should elapse between two successive crushings. 



6. It is not economical to allow badly crushed megass to pass the first mill 

 on the supposition that the subsequent wet crushing makes up for the loss ; it 

 does not. 



7. The whole duty of maceration depends on the completeness of the 

 admixture. 



Source of Water for Saturation. The water which is used in 

 maceration is conveniently derived from the condensed water in juice heaters, 

 eliminators, or effects. In the first two, the water being under pressure no 

 pump is required. If the multiple effect water be used, it is convenient to pump 

 it to elevated tanks, and thence to allow it to gravitate to the mills. By this 

 arrangement the water can be measured, a point of considerable importance in 

 technical control. Very often the maceration water is derived from the hot 

 water supply for the boilers, a pipe being led from the boiler feed pump to the 

 mills. 



Algebraical Treatment of the Extraction of Juice from 

 Canes. Let/ and m denote the fibre per unit weight of cane and of megass ; 



then the weight of megass per unit weight of cane is 2- and the weight of 



m 



juice expressed is ; the weight of juice per unit weight of cane is 1 / 



so that the juice extracted per unit weight of juice in the cane is m ~" ' 



ftl-m) (*-/) 



The weight of juice remaining in the megass is and the juice lost in 



the megass per unit weight of juice in cane is - . As the fibre in 



the cane increases, that in the megass remaining constant, the weight of juice 

 extracted by the mills decreases ; in the annexed table are given values of the 



expression for values of / 8 to 1 6 and of m 35 to 45 ; that is to say, 



the weight of juice obtained per 100 cane, when the latter contains from 8 per 

 cent, to 16 per cent, of fibre, and when the megass contains from 35 per cent, 

 to 45 per cent. 



* The distribution of the water by means of injectors as described by L. Pellet at the 1909 

 Congress of Applied Chemistry would appear to fulfil these requirements ; their use would in 

 any case be superior to a perforated pipe or to a distributing trough. 



205 



