CANE SUGAR. 



liquor just fast enough to replace that passing away as vapour and through 

 the discharge. The latter is controlled by the hand valve g ; by opening it 

 the discharge is increased, causing the level of the liquor in the float box to 

 fall, and admitting a larger feed. The path of the juice is from the float box, 

 through the pump and connecting piping up into the manifold box on the 

 back of the tube plate, thence into the several distributing tubes through the 

 slots of which it passes as a fine shower over the evaporating tubes to the float 

 box to again make the same journey, part passing through the discharge pipe 

 to the next effect. The steam enters by the pipe g, passes inside the tubes, 

 the condensed water flowing down and being trapped at , whence it passes on 



FIG. 170. 



to the next effect, the evaporated vapour passing by way of h to the following 

 body. The Lillie evaporator differs from others in the following points. The 

 juice under evaporation is always in a state of film or rain, and hence there is 

 no tendency for the boiling point to be elevated through the pressure of a 

 column of liquid and thus to diminish the efficiency of the heating surface. 

 The quantity of juice in process of evaporation at one time is very small and 

 is consequently under treatment but a short time. The state of subdivision 

 of the juice allows a free and easy disengagement of vapour without spurting 

 and tends to diminish entrainment losses. 



300 



