THE CLARIFICATION OR DEFECATION OF THE JUICE. 



vacuum of about six inches ; the superheated juice from the digesters is dis- 

 chai ged into this vessel ; in the upper part of the absorber is a tubular element 

 cc within the tubes of which the cold juice circulates; the superheated juices 

 on entering the absorber at once boil under the reduced pressure, and the 

 vapours given off condense on the tubular element, at the same time raising 

 the temperature of the cold juice therein contained. 



The Settling Tank. The continuous settling tank is shown at dd\ it 

 consists of a cylindrical portion mounted on a funnel-shaped lower part. 

 Inside is arranged a truncated cone of sheet iron. The juice enters through 

 four pipes and follows the course indicated by the arrows, depositing its 

 suspended matter on the sides of the tank, and on the cone ; on leaving the 

 tank the juice passes direct to the evaporators. Periodically the deposit of 

 dirt is discharged through the pipe at the bottom of the tank and sent to the 

 presses. The settler shown in Fig. l/tf is closed ; in the earlier plants open 

 settlers were used, and these tanks were often arranged in series, the juice 

 from the first tank dividing into two currents, so that the velocity of flow was 

 halved, and an opportunity given for a thorough deposit of the dirt. 



The Deming plant is sent out equipped with carefully thought out 

 arrangements for the control of liming and sulphuring and of the temperatures- 

 in the various parts of the plant. So as not to cause confusion these arrange- 

 ments are not shown in the drawing, which is confined to the essential parts of 

 the apparatus. 



Mechanically, and from the point of view of steam economy, there is no 

 doubt that this process is very efficient, but from the chemical standpoint it 

 has been subjected to very severe criticism; any slight error in controlling the 

 amount of lime or sulphur gas added will, at the high temperature which forms 

 a part of the process, result in a serious loss of sugar ; and in a number of 

 instances where the plant has been installed the superheat part of the scheme 

 has been dropped, the mechanical ideas being retained. 



The following figures dealing with the process are due to Beeson 22 : 



Juice. s al sucrose. S s 1 jJ ai I ? ot Purity. Glucose. 



Diffusion 14-9 .. 11-22 .. 1-69 .. 75-3 .. 1-99 



Ordinary Clarification 14'9 . . 12-04 . 0*83 . . 80'9 . . 2-03 



Deming Clarification .. 14'9 .. 11-58 .. 1-29 .. 77'7 .. 2-03 



Diffusion 14-9 11-78 . . 1-11 . . 79-1 . . 2-01 



Ordinary Clarification 14'9 .. 11-65 .. 1-21 .. 78'2 .. 2'04 



Deming Clarification . 14'9 .. 10'85 .. 2'06 .. 72-8 .. 1-99 



Tn s po Glucose Total Albumen- 4 i/i oa Alcoholic 



ratio. Proteids. oids. Amides. Precipitate . 



Diffusion 17'7 . . -248 . . -0617 . . -1863 . . -105 



Ordinary Clarification. 16'9 . . -205 . . '0416 . . '1634 . . -202 



Deming Clarification .. 17'5 .. -208 .. -0434 .. -1646 .. '171 



Diffusion 17-1 . . -215 . . -0733 . . -1417 . . -246 



Ordinary Clarification. 17'5 . . -201 . . -0538 . . '1472 . . -336 



Deming Clarification . . 18-3 . . -202 . . -0447 . . '1574 . . -297 



259 



