CANE SUGAR. 



sugar in the cake is not, as a rule, effective. A rather different system is now 

 usually followed. In Fig. 158 are shown, in section, the types of plate used. 

 One plate is solid, and the other consists of a frame only, a. The solid and 

 hollow plates are placed in the press alternately. At the angles of both frame 

 and press are the circular openings b and c, so that in this press there are two 

 conduits, that at b is for the passage of the juice, and that at c for the washing 

 water. The channel h, in the hollow plates, conducts juice to the interior of 

 the press, and in the solid plates there is a similar channel i. A light joint is 

 made along the conduits by placing indiarubber rings, d, in the closed openings 

 b or c, as the case may be. At g in the solid plate is an opening communi- 

 cating with the cock/. Bags without openings are hung over the solid plates? 

 but do not cover the conduits b or c. Scums being forced into the press by 

 the conduit b, pass through the channels h and fill the spaces between the two 

 solid plates formed by the hollow plates. The clear juice passes out through 



<gr 



IDC: 

 /i 



FIG. 153. 



g, the scums being caught between the bags. To wash the cake, water is 

 forced through the conduit c, and passes through the cake in a direction 

 opposite to that by which the juice travelled. The advantage of this type of 

 press over the central feed press is that the washing is more effectively per- 

 formed, and that the bags not needing to be cut have a longer life. 



Capacity of Filter Presses. To filter scums an allowance of 

 two square feet of filtering area for every gallon per hour is necessary, and 

 taking the scums as 10 per cent, of the volume of the juice, two square feet 

 of filtering area should be allowed for every 10 gallons of juice per hour ; this 

 is a minimum allowance and should be increased at least 25 per cent, to allow 

 for time lost in changing cloths, &c. Where, as now is often the case, the 

 scums are thoroughly washed, or are re-pressed, a greatly increased capacity 

 is called for. 



276 



