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The World's Commercial Products 



IN A SUGAR REFINERY 



Charcoal Filters for Clarification of Sugar 



practised in the preparation of starch from 

 cassava, arrowroot, potatoes, etc. The 

 soft pulp so obtained was squeezed either 

 by placing it first in small, strong sacks 

 and submitting it to hydraulic pressure, 

 or by passing the pulp through specially 

 designed rollers and afterwards filtering 

 it. None of these methods proved very 

 successful and they were abandoned in 

 favour of extraction by diffusion, which 

 appears to have been first practised in 

 about 1830. This method is now solely 

 used in the beet-sugar industry. We 

 have already discussed the reasons why 

 it is not generally applicable to the sugar- 

 cane, although comparatively recently 

 Mr. Naudet, who has done so much for 

 the beet-sugar, has designed a method 

 which is being employed very successfully 

 in several parts of the world. 

 From the field direct, or these storing-places or siloes, the roots are conveyed in carts to the 

 factory, where they pass through an elaborate series of mechanical and chemical processes. In 

 the factory the root first comes in a complex of tubes through which a powerful stream of water 

 flows; the root turns and revolves in all directions and on its way leaves behind part of the earth, 

 which still sticks to it, notwithstanding the scraping of the gatherers or of the forward harvesting- 

 machines. The root is carried along to the washer, a machine whose arms, provided with hard 

 pieces of wood, shake it, rub it, and knock it about, while particles of sand and stones which 

 have possibly been carried with it fall to the bottom. Then the beetroot rolls into the cylin- 

 drical chest of the cutting-machine, the bottom of which, consisting of curved knives in rapid 

 revolving motion, cut it up into small rectangular pieces or into thin slices. These escape through 

 the openings between the curves of the knives and fall into the diffusing pans through a tube, 

 which turns on its axis and is fastened to the back part of the cutting machine, in such a way 

 that it can distribute the uninterrupted supply of pieces of beetroot over the diffusing pans, 

 arranged next to one another and together forming what is called a battery. As a rule a battery 

 consists of ten or twelve diffusing pans. On the first day of the campaign each pan receives 

 its supply of pieces. The pans are numbered from one to ten or twelve. No. 1 is at the head of 

 the battery and No. 10 or 12 brings up the rear. A certain quantity of water is poured into 

 No. 1, heated by steam, in which part of the sugar contained in the pieces of beetroot is dis- 

 solved ; then by means of an ingenious system of taps the water flows on to No. 2, in which 

 there are fresh pieces of beetroot, consequently containing more sugar than those in No. 1, 

 irom which the sugar has already been partly extracted. In this way the liquid becomes 

 sweeter and flows on to No. 3 and so on, its percentage of sugar always increasing at the cost 

 of the pieces of beetroot. As the water supply continues to flow, the contents of the first 

 diffusing pan are exhausted first ; the pieces do not contain anymore sugar, the mass has become 

 pulp and falls into a separate division, after which all the water is squeezed out in powerful 

 presses. 



After the pulp has been discharged the first division of the battery is filled again with fresh 

 pieces of beetroot and now becomes the last of the series, while No. 2 takes the lead. So each 

 diffusing pan in its turn is the first and the last, the first when the pieces of beetroot are nearly 

 exhausted, the last when they have received a fresh supply. The diffusion process is so 

 efficient that it extracts about ninety-seven per cent, of the total sugar in the beetroots. 



