THE CONCENTRATION OF THE SYRUP TO MASSECUITE. 



crystals already present. It should be the object of the sugar maker to so 

 control the rate of cooling that the supersaturation does not increase, and that 

 the deposit of sugar keeps pace with the rate at which the massecuite cools. 

 The advantage of jacketed containers in a crystallization in motion process is 

 connected with the point explained above ; namely, that a means is provided 

 whereby the rate of cooling can be controlled. 



Fig. 198. 



Forms of Crystallizing: Tanks. The receptacles in which the 

 massecuites are received in order to be cooled in motion are either U shaped 

 or cylindrical horizontal vessels ; they are constructed of boiler plate, and are 

 made either closed or open. Through the centre of the vessels passes a shaft 

 to which is attached the stirring apparatus ; motion is usually transmitted to 

 this shaft by means of a wheel and worm gear, the wheel being attached to 



FIG. 199. 



one end of the shaft ; the tanks are so arranged that one worm gears with the 

 wheels of the whole battery. The tanks are made either plain or provided 

 with a jacket, into which steam or water can be admitted, and thus control 

 the rate at which the massecuite cools. A. general form of crystallizing tank 

 is shown in Fig. 198. 



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