CANE SUGAR. 



Control of the Pan and Centrifugal Plant. Following on 

 what has been written in the chapter on the vacuum pan, the cardinal points 

 in this control are the determinations of the sugar in crystal form, and of the 

 actual water content of the massecuites and molasses. A comparison of the 

 sugar actually present as crystals, with the amount obtained in the manufac- 

 turing process gives the amount lost either at a certain stage or totally lost in 

 the waste molasses ; this determination may be checked by analysis of the 

 molasses as they actually leave the baskets, and of the same molasses after 

 removal of fine grain by filtering through glass wool ; this source of loss is to 

 be looked for either in the pan (uneven grain due to lack of craft skill) or to 

 the use of an unsuitable mesh in the centrifugal gauze. 



The systematic determination of the water content of the massecuites, 

 determining as it does the amount of sugar crystallized, is naturally of great 

 importance. 



A systematic record of the working of the massecuites should be kept ; 

 the data recorded by the writer when engaged in supervising a crystallization 

 in motion plant included the following determinations : 



Date, number, density, volume, and weight of each strike ; purities of 

 the syrup and the molasses used and of the strike and purgings ; dry matter 

 in the strike and in the purgings ; weight and polarization of the sugar 

 obtained. 



It may be mentioned that the apparent purities may be used in calcu- 

 lating the proportion of syrup and molasses to be used in making a strike. 

 Success in this department depends very largely on an organized system of 

 technical book-keeping. 



Control of Entrainment Losses. This term is usually taken 

 to include all undetermined losses, and much of this is due to errors of analysis. 

 Entrainment losses properly so called, due to sugar carried away mechanically 

 in vapours from the boiling apparatus, are, with modern well-designed plants, 

 reduced to a minimum ; nevertheless the waste waters from the evaporators 

 and pans should be systematically sampled and examined for sugar by one or 

 other of the sensitive colour reactions ; if any notable loss of sugar is indicated 

 the same may be determined by the usual methods after evaporation to small 

 volume of a large quantity of the suspected water. 



Inversion Losses. In a well-regulated factory these should be 

 entirely absent, even when white or yellow crystals are being made ; care- 

 lessness or the use of an excess of acid may lead to serious losses ; it is perhaps 

 impossible to estimate accurately these losses, since with alkaline juices there 

 is a tendency towards the destruction of reducing sugars ; hence any increase 

 in the glucose over that initially present is to be regarded as pointing to an 

 avoidable loss, the exact amount of which cannot be definitely stated. 



510 



