CANE SUGAR. 



The Yaryan. The Yaryan eYaporator, shown in longitudinal section 

 in Fig. 167, and in end sectional elevation in Fig. 168, consists of a horizontal 

 body or shell of steel plate or cast-iron depending upon size and steam 

 pressure within which is grouped a series of tubes about 3 inches diameter ; 

 these tubes are expanded into the tube plates as shown, and at each end 

 * return heads ' are bolted on, thus forming a connection which ensures the 

 continuous flow of the liquor through each coil or tube system. 



Steam, or vapour from a preceding shell or effect, enters the shell at e 

 and surrounds the outside of the tubes containing the liquor to be evaporated. 



d 



FIG. 168. 



The liquor entering pipe d is forced, under pressure by a pump or 

 otherwise, into the top tubes, and only partially fills their bore, thereby 

 allowing space for the vapour arising from the heated liquor to pass freely 

 away. The liquor passes along with a rapid and continuous motion through 

 the series of tubes and discharges at g, the concentrated liquor and its vapour, 

 passing along pipe/, falls into the separator h, shown in section in Fig. 168. 

 The vapour passes, as indicated by the arrows, up and down the two baffle 

 plates b b, where it emerges into pipe k which leads direct to shell of next 

 vessel, or to condenser if from the last effect. 



298 



