The eystem is receiving considerable attention from beet-sugar makers in France, though devised more especially for cane-sugar. One manufacturer, whose diffusion procees gives a very low juice (sometimes only 21° B., and generally not more than 3f° B.), states that with the ordinary arrangement of the triple-effect he evaporated 1800 hectol. (of 22 gal.) of juice at 3.2° B., with 150 /weed. of milk of lime, making a total of 1950 hectol. to 18° B. per 24 hours ; with Rillieux's modification, he evaporated to 25° B., which, with the increased quantity worked off, is equal to a total evaporation of 5158 heetol. per 24 houre, or a gain of 3208 hectol. This gain is said to be effected at the cost of only a little (quantity not stated) additional steam. The Milieux apparatus is now rarely used in Louisiana, being considered too complicated for plantation purposes ; the tendency there is towards very large eingle vacuum-pans.
e. Bath-evaporators.—This system may be illustrated by the plan adopted by F. A. Bonnefln, of Guadeloupe, whose capillary filter has already (p. 1889) been described. The apparatus is intended for use with the filter, and is made by the same firm.
The tempered juice, prior to evaporation, passes through a " continuous preparator,'' a metallic vessel 32 ft. long and 18 ft.
broad, divided by partitions into 4 chambers of 2 ft. in width ; each chamber has a central par tition not quite extending to one end, with boles for the inlet and outlet of aleating liquid, which therefore travels 36 ft. in the chamber, on leaviog which it is reheated. On the partitions, is a copper pan divided so as to form a continuous zigzag channel, about 1100-1700 ft. long, the bottom being immersed in the heating liquid circulating in the chambers below. The juice is admitted at one end, and issues at the other. Along one side of the pan, are hollows to collect the heavy bodies de posited during the flow of the liquid.
The juice, introduced at 15° (59° F.), being in contact during a travel of 1100 ft. or more with a liquid at about 99° (210° F.), leaves the further end of the pan at 80°-90° (176°-194° F.), de prived of heavy organic or inor ganic matters in suspendon, and of light matters which become separated and rise to the surface. It succesthvely fills capillary filters (p. 1889), and is delivered in a pure state to be concen trated.
The vacuum - pan is con structed like the preceding, with modifications to maintain the heat in the coils at about 99° (210° F.), the heat being regu
lated in proportion to the juice being more and more concen trated, and always below 100° (212° F.) For generating heat, Bonnefin employs a small fur nace for heating oil to 250°-280° (482°-536° F.). This hot oil is conveyed through a coil of pipes in a vessel containing water, and connected with the vessel which receives all the condense-water of the factory. After the oil has done duty in tbe evaporating apparatus, it is returned to be reheated by the furnace.
f. Fryer's Ooncretor.—In Fryer's concrctor, no attempt is made to produce a crystalline article, but only to evaporate the liquor to such a point that when cold it will assume a solid (concrete) state. The mass is removed as fast as formed, and being plastic while warm, it can be cast into blocks of any convenient shape and size, hardening as it cools. In this state, it ean be shipped in bag,s or matting, suffering neither deliquescence nor drainage. The e.”-t of an apparatus capable of making 10 cwt. per hour is about 10001. It is the invention of Alfred Fryer, of Manchester and Antigua, and ia made by Manlove, Alliott, Fryer, & Co., Nottingham and Rouen. It is shown in side elevation and plan in Figs. 1380, 1381. It consists of a series of shallow trays A, placed end to end, and divided transversely by ribs running almost frorn side to side. At one end of these trays is a furnace B, the flue of which runs beneath them ; and at the other end, are a boiler C and an air-heater D, which utilize the waste heat from the flue, employing it both to generate steam and to heat air for the revolving cylinder.
The whole series of treys A is placed on a slight incline, the upper end being next the furnace. The topmost 3 tmys are made of wrought iron, since the intense heat here would render cast-iron liable to fracture. The clarified juice from the pipe M flows first upon the tray nearest the furnace; it runs down tho incline towards the air-heater D, meandering from side to side in a shallow stream. Thus it has to traverse a channel 400 ft. long, before it can leave the trays at the end adjacent to the air-heater, although the distance betweeu the furnace and the air-heater in a direct line is not quite 50 ft. While flowing over these trays, the juice is kept rapidly boiling by means of the heat from the furuace; and although it only takes 8-10 minutes to traverse, its density is mised from about 10° B. to about 30° B.