For a few moments, on its way to a steam and juice separator, where the steam due to the superheated juice flashes off, and is either utilized for aiding the steam supplied to the multiple effect evaporators, or for heating cold juice on its way to the main heater, or it is allowed to escape into the atmosphere.
The clear juice when it arrives at the top of the separator flows slowly over the level edges of, a cross canal and passes in a continuous stream to the service tanks of the evaporators or vacuum pan.
The juice is then drawn off and pumped up to one of the double-bottomed defecators and redefecated, or, where juice-heaters have been used instead of defecators, the scums from the separators or subsiders are heated and forced through filter presses, the juice expressed going to the evaporators and the scum cakes formed in the filter presses to the fields as manure.
It is unquestionably better and easier to evaporate in vacuo than in an open pan, and with a better system of firing, a more liberal provision of steam generators, and multiple-effect evaporators of improved construction, a far larger yield of sugar is obtained from the juice than was possible of attainment in those days, and the megass often suffices as fuel for the crop.
With the juice of some canes considerable difficulty is encountered in keeping the heating surfaces of the evaporators clean and free from incrustations, and cleaning by the use of acid has to be resorted to.
Apart from increased yield in sugar of good quality, we may sum up the advantages procurable from the use of Hatton defecators as follows: cold liming; heating gently to the temperature required to coagulate the albumen and not beyond it, whereby disturbance would ensue; the continuous separation of the scums; the gradual drying of the scums so as to make them ready for the fields, without carrying away juice or requiring treatment in filter presses; and the continuous supply of hot defecated juice to the evaporators, without the use of subsiding tanks or eliminators; and, finally, the saving in expenditure on plant, such as filter presses, &c., and wages.
The processes of manufacture have been improved by the introduction of specially constructed evaporators, and quantities of maple sugar and syrup are annually exported.