THE EVAPORATION OF THE JUICE TO SYRUP. 



Table giving Velocity of Water at Exit under a Head of 16 feet for 

 different Conditions of Pipe. 



The calculation of the volume of gases removed by the pump is sa 

 unsatisfactory as not to repay study. A certain quantity of air enters the 

 apparatus dissolved in the juice, which is released on boiling, and the juice 

 itself in treatment forms a certain amount of gas ; air, too, will leak into the 

 apparatus, and some will be introduced dissolved in the injection water. 

 Experimental data are so incomplete on these points that they can give little 

 or no help to practice. 



LOSS of Heat in Evaporators. In a naked quadruple standard 

 evaporator let the temperatures in the vessels be 



i. 

 212 



II. 

 203 



ill. 

 187 



rv. 

 140 



With external air at 82 P. 



the excess temperature is 130 121 105 58 



Interpolating from the table given in Chapter XIX. the heat losses per 



square foot per hour are 



B.T.TJ. 



I. II. III. IV. 



336 308 252 126 



Let the area of shell and vapour pipes be * 2 of the total heating surface, 

 then each vessel exposes an area '05 of the total heating surface, and the 

 losses per hour per square foot of heating surface are 



I. II. III. IV. 



17 16 13 6 



323 



