Vacuum Pan Research Articles

Sugar Factories and Sugar Machinery

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.

An Internally Heated Laboratory Vacuum Pan.

An Internally Heated Laboratory Vacuum Pan.

A Vacuum Pan for Laboratory and Experimental Use

A Vacuum Pan for Laboratory and Experimental Use

Societies and Academies

LONDON. Society of Chemical Industry, January 5.—Dr. W. R. E. Hodgkinson in the chair.—J. L. Strevens: The viscosity of oils. The author, after emphasising the importance of the determination of absolute viscosity and its relation to temperature for any particular lubricant, proceeds to correct certain figures previously published.—L. T. Wright: The oxygen content of the gases from roasting pyrites. The author on examining a number of analyses of “burner” gas from i various sources noticed that the oxygen “deficiency” is the greater the greater the dilution of the gas, and i this suggests that there is in addition to the well known production of SO3 and metallic sulphates some I other cause, such as a constant error in the analyses,? which influences these. In any case, the evidence of i these gas analyses shows that the manner in which the oxygen is disposed of would prevent the “burner” gas containing more than about 12 per cent, of SO2 as a maximum when all the oxygen of the air supplied was used up, and the author states that his various attempts to obtain more than this in practice by keeping burner gas long in contact with incandescent pyrites have failed.—L. C. Jackson, L. McNab, and A. C. H. Rothera: The electrical conductivity of milk -during the concentration, with suggestions for a practical method of determining the end point in the manufacture of sweetened condensed milk. Although the measurement of electrical conductivity is of no value in determining the degree of concentration of a separated unsweetened milk, it can be made the basis of a working process for watching the concentration of sweetened whole milk:. A device in which the resistance of sweetened milk in the vacuum pan is compared with that of an approved sample of condensed milk maintained at exactly the same temperature is described.—S. J. Johnstone: Monazite from some new localities. Wide variation may occur in the quantity of thoria present in samples; notable amongst these are ranges shown by those.from Ceylon, the thoria percentage of which varies from 9.5 to 28.2; from Malava, 3.4 to 9.4; and from northern Nigeria, 2.3 to 8.0.