Sugar Factories and Sugar Machinery

Abstract

Figures for the total annual production of sugar show that it forms one of the great crops of the world, and the machinery used, both in handling the canes and in the factory, is of considerable importance. The author describes the method of sugar production, beginning with the supply of cane from the field to the factory, and then describing the simple defecation, sulphitation and carbonatation processes. An account is given of the actual machinery used in sugar factories, and the design of crushing mills is considered. In all modern mills the top roll is fitted with a hydraulic pressure regulator. Until recently the majority of hydraulic attachments which came under the author's observation were badly designed or totally unsuited for their purpose. This was largely due to failure to realize the large amount of friction which can occur in the accumulator rams, in the rams in the cap, and in the bearing which slides in the gap in the mill cheek. The methods adopted to overcome this in the best modern practice are described. The methods of driving, by steam engines or electric motors, are discussed, and mention is made of the types of motors in general use. The variable factors are such that it is not possible to lay down any general rule as to the power necessary, but from a large number of examples in operation it has been found that the power required varies from 10·5 to 12 h.p. per ton of cane ground per hour. To cover faulty operation of the plant a fair margin of power is usually allowed in the prime mover. Diagrams are given showing the variation in the power required at different points in the mill and at different times in the working day. The author then deals with the chief points in the design of evaporators, vacuum pans, and crystallizers. There is little waste in a sugar factory, and the refuse products or “bagasse” are used as fuel in the boilers. Some practical points in connexion with the use of this form of fuel are given, and the author concludes with some remarks on the layout of sugar factories. In an Appendix an analysis of the costs of crop, manufacturing expenses, and maintenance is given.