596 



SUGAR-BEET 



SUGAR-BEET 



which permits of the extraction of the sugar from 

 the cossettes regardless of how they lie in the dif- 

 fusors, and at the same time does not retard the 

 circulation of the juice. There are openings at the 

 top for filling the cells and at the bottom for 

 emptying after the sugar has been extracted, tight- 

 fitting doors being used in all cases to close these 

 openings. Near the bottom of each cell and above 

 the opening of the pipe there is a screen of heavy 

 sheet iron for the purpose of preventing the cos- 

 settes entering the juice as it leaves the dift'usor, 

 thus resulting in a stoppage of the pipe. 



The principle of diflfusion is based on the theory 

 of osmosis, and, as sugar belongs to the category 

 of crystaloids, the advantage of the diffusion pro- 

 cess over all others for the extraction of the sugar 

 from the sugar-beet will be easily understood. 

 Owing to the fact that a certain number of the 

 cells in the beet become either broken or cut in the 



Fig. 823. Carloads of sugar-beets at the factory 



course of their passage through the slicer, thus 

 allowing the contents of the cells other than sugar 

 to pass into the juice, which would otherwise be 

 absent, it will be seen why it is necessary to 

 watch the knives and to take such precautions as 

 will tend to keep them in the finest possible condi- 

 tion. Keyr estimates that about 6.41 per cent of 

 all the cells of the beets are either crushed or torn 

 in the slicing. 



Care must be taken in the way the battery is 

 worked, for, should the water remain too long in 

 contact with the tissue of the beet, or reach too 

 high a temperature, other impurities than those 

 which pass into the juice from the broken cells 

 would be absorbed by the water and produce 

 trouble in the further treatment of the juice. The 

 cell walls of the cossettes contain organic salts of 

 lime and potash, and pectic compounds which be- 

 come dissolved under the influence of too high tem- 

 perature. As an example : Asparagine and gluta- 

 min, by heating in the presence of an alkali, are 

 converted into apparetic and glutaminic acids, 

 which, in the combination with alkalis, remain as 

 salts in the juice ; by the above heating, ammonia 



is constantly given off, which tends to show a 

 higher percentage of alkalinity than is really 

 present. This interferes with the work- at the car- 

 bonatation stations. The best working temperature 

 of the battery is between 75° and 80° Centigrade, as 

 above 80° there is a tendency for the pectine and 

 the pectates to be absorbed from the cellulose of 

 the beet, and this, as well as the high alkalinity at 

 the carbonatation stations, tends to make the presses 

 slimy and hard to wash. Frozen beets take an en- 

 tirely different temperature from those that are 

 fresh from the field. The size of the slices as well 

 as their thickness has an infiuence on the circula- 

 tion of the water through the cells if the tempera- 

 ture is not right. 



One of the most important stations in the sugar- 

 house is the diffusion battery, and when that is in 

 good working order, with everything moving 

 smoothly, it can safely be said that the entire 

 house is working all right. 



Starting the operations. — In 

 starting the factory at the be- 

 ginning of the season, it is neces- 

 sary to fill eight or nine cells of 

 the battery before making the 

 first draw of juice that is to be 

 sent to the first carbonatation 

 station for treatment. When 

 the proper number of diffusors 

 have been filled, a certain num- 

 ber of hectoliters of the juice, 

 containing sugar extracted from 

 the beets, are measured off and 

 sent to the first carbonatation 

 station, for the purpose of clari- 

 fying and thus rendering the 

 juice in a condition more easily 

 to be treated for the process of 

 boiling, when the sugar is se- 

 cured by crystallization from a 

 highly concentrated syrup. 

 As the juice is drawn off and the cossettes be- 

 come more and more exhausted of their sugar con- 

 tent, it becomes necessary to replace them with 

 fresh cossettes. This is done by shutting off the 

 circulation in the cell to be refilled, emptying it by 

 opening the door at the bottom of the cell, clos- 

 ing this door and refilling as at the beginning. 

 This is continued at regular intervals in order that 

 the process of diffusion may be continuous and that 

 the best results may be secured. The beets remain 

 in contact with the water at the temperature of 

 70° to 80° for one hour, when nearly the entire 

 amount of the sugar has been extracted. The ex- 

 tracted cossettes are carried to the pulp pile and 

 can be used to good advantage in the feeding of 

 stock. 



First carhormtation. — The first carbonatation sta- 

 tion consists of several tanks into which the juice 

 is pumped and milk of lime added, having the den- 

 sity of 18° to 22° Baume, the amount being figured 

 at the rate of 3 per cent of dry lime to each ton of 

 beets, and in terms of liters of juice. The addition 

 of the lime to the diffusion juice is the most impor- 

 tant operation in the sugar mill, and experience 



