CANE SUGAR. 



temperature of the juice is self -con trolled by a thermostat ; at g is shown a 

 tube filled with water ; the expansion and contraction of the water acts on a 

 diaphragm in the regulator h and thereby operates the balanced valve at . 



Juice Heater. A juice heater, Fig. llj.3, consists of a vertical or 

 horizontal cylindrical cast iron body. 



At the upper and lower ends are placed tube plates which cany the tubes 

 within which the juice circulates, low pressure steam enters at a, the con- 

 densed water is collected at c, the juice enters at b, and is caused to change its 



rr 



FIG. 143. 



direction twice by the partition plates at e, passing out at /; at d are shown 

 scum cocks for emptying the vessel after cleaning. 



As a rough rule, for every five gallons of juice per hour, one square foot 

 of heating surface is required. 



Instead of heating the juice with back pressure steam from the engines, 

 juice heaters are sometimes attached as surface condensers to the last body of 

 the multiple effect evaporator. "Where a good vacuum in the last body is 



244 



