Annual Report 1961 - BEEP

-88-From the tables it is noticed that, since therefractometer sucrose % mixed juice is higherthan the corresponding densimetric value by0.01, there appears to be very slightly moresugar in the mixed juice of the refractometercontrol, and this results in a Boiling HouseRecovery figure lower by a maximum of 0.1.At Factories Band C, the refractometer S.l.M.recoveries were between 0.0 and 0.1 higher thanthe densimetrie values, this difference being dueto the fact that suspended solids in the mixedjuice affect the hydrometer to a much greater extentthan the refractometer. As a result of thisdifference in S. J. M. recovery and of the differencein B.H.R., the refractometer BoilingHouse Eff'iciencies were lower than the dcnsimetrievalues by 0.2 at Factory Band 0.1 atFactory C. Since it happens every now andthen that Boiling House Efficiencies higher than100% are obtained with densimetric control,the lower values obtained with refractometercontrol are more realistic.At Factory A, over the short period of oneweek, the difference in the SJ.M. recoverieswas much greater, namely 0.6. This largedifference was mainly due to the fact thatrefractometer sucrose % molasses was lowerthan the densimetric value. At the three factoriesthe amount of recoverable sugar at 100%RH.E. was slightly lower for the densimetricfigures since both refractometer sucrose o~mixed juice and refractometer SJ.M. recoverieswere higher than the corresponding densimctricvalues.Refractometer sucrose % cane being 0.01higher than the densi metric value, total losseswere consequently 0.0 I higher too. At FactoryC, the sucrose content of the molasses beingnearly equal for the two controls, sucrose lossesin molasses ~'l; cane were also equal for both.At the other two factories, that was not thecase, and differences of 0.01 and 0.02 respectivelywere obtained. Hence, a difference of0.03 in undetermined losses occurred at FactoryA, 0.02 at Factory B, and 0.01 at Factory C.The refractometer offers several advantagesover hydrometers, the most important of whichare:(a)(b)(c)(d)(c)it yields more accurate Brix values that liecloser to the dry substance than correspondinghydrometer values,it is simpler to use,it necessitates only a small sample,the Brix determination is carried out muchmore quickly than with the hydrometer.it is a robust apparatus of a long life span.In view of these advantages, it is recommendedthat as from next year all factoriesshould be equipped with precision refraetometers.In order to enable the staff to become familiarwith the range of values of Brixes and puritiesencountered with the refractometer, parallelcontrol with the refractometer and hydrometersshould be carried out during several weeksbefore the hydrometers arc discarded.This will moreover provide for each factorya set of data that should be useful for comparisonsof factory performance in years beforeand after the transition from densimetric Brixesto refractometer Brixes.REFERENCESLAMUSSF, J. P. (1960) Preliminary studies in the useof the refractometer for routine chemical control.Rep. SlIg. Ind. Res. [fist. Mauritius: 101 - 103.HANSSON, F. (1940) Bausch and Lamb precisionrefractometer. Huwuii. Sit.!!. Plant. Assoc. Evp,Sta. Sug, Tech. Dept. Activities Rep. 4.HAWAIIAN SUGAR TECHNOLOGISTS (1955)Official methods of the Hawaiian Sugar Technologistsfor Control of Cane Sugar Factories,Revised Edition.SOCIETE DES CHIMISTES ET DES TECHNICIENSDES INDUSTRIES AGRICOLES DE MAURICE.(1948) System of Chemical Control for CaneSugar Factories.