A modification of the system of double-bottom defecators has lately been introduced with considerable success in San Domingo and in Cuba, by which a continuous and steady discharge of clear defecated juice is obtained on the one hand, and on the other a comparatively hard dry cake of scum or cachaza, and without the use of filter presses.
After the juice has been defecated or purified by any of the means above mentioned it is sent to the evaporating apparatus, hereinafter described, where it is concentrated to 26° or 28° Beaume, and is then conducted in a continuous stream either into the service tanks of the vacuum pan, if dark sugars are required, or, if a better colour is wanted, into clarifiers.
An economical method of evaporation must be found.
The defecated cane juice, having lost about 70% of its bulk by evaporation in the multipleeffect evaporator, is now syrup, and ready to enter the vacuum pan for further concentration and crystallizaHoward's tion.
It is of course presupposed that the juice has been properly defecated, because without this no amount of skill and knowledge in cooking in the pan will avail; the sugar resulting must be bad, either in colour or grain, or both, and certainly in polarizing power.