Begass coming wet from the mill requires to be dried to render it fit for fuel, and it receives its preliminary drying in the external furnace. A coal fire having been first lighted in A, its walls become highly heated ; the wet begass is then fed in through C, whose balance-door D gives passage to and spreads the began uniformly npon the grate g, closing again immediately to re-establish the draft through the grate. In this arrangement, the heat which would go to evaporate the water, is stored up in the walls of the furnace, which quickly become hot enongh to almost instantly dry the begass, aud render it eminently fit for burning. As all the gases are com pelled to pass through the mouth leading to the boller-furnace s, perfect combustion is ensured, and there is little or none of the usual deposit in the boiler-tubes. The advantages of a furnace which will burn wet begat*, extknd to the important gain represented by the avoidanee of risk of fire, constantly to be feared when dried bogus is stored in large quantity. The Marie furnace has been applied also to the "copper walls" for making muscovado sugar.
Norbert Rillieux, of Paris, also has a plan for drying the begass on its way to the furnace. His apparatus is shown in Figs. 1340, 1341. The wet begass is delivered by elevators a into the hopper b, leading at bottom into a chamber communicating vvith the furnace c of the steam-boiler h.
In this hopper is a hinged horizontal flap d, on which the begass falls, and which is held by a balance-weight till the load accumulated upon it overbalances the weight, when the begass if3 dis charged down the ohamber, and passes into the furnace to be burnt, the flap being closed again by the balance-weight. While the begass is retained in the hopper, and descends through the chamb,er, it is subjected to currents of hot gases from the furnace, so as to become dry before passing into the fire. The hot currents may be accelerated by connecting the hopper by a pipe e with the chimney f of the boiler, the draught being regulated by a throttle-valve ; and if required, a blowing-fan g may be provided in the pipe, and regulated so as to :produce the required degreo of desiccation.
Disintegrating. —The imperfect liberation of the cane-juice by the crushing process of the ordinary mill has led to experiments in other directions. One result has been the invention of machines for effecting a more thorough mechanical disintegration of the cane-tissue. These may be conveniently considered under three sections :—(a) Defibrators, (b) Bessemer's press, and (c) Bonnefin's rasper.
a. Defibrators.—This term (Fr. defibreur) is employed by several inventors. In Mignon et
Rouart's, the cane is reduced to pulp, and by subsequent pressure, 77 per cent. of juice is said to be separated by the first crushing, and a further 25 per cent. on the weight of the begass by a second operation. The ma,chinery is in operation in Guadeloupe.
Faure's defibrator, made by Manlove, Alliott, Fryer, & Co., is shown in perspective in Fig. 1342, and in horizontal section in Fig. 1343 : a is a shaft carrying a cylinder, whose surface is provided with teeth running in a helical direction ; b, a strong frame ; an articulated cane-canier receives its motion from the defibrator itself ; c, inclined plane bringing the canes in front of the cylinder; e strong spur-wheel fixed to one end of the shaft u, and receiving motion by a pinion f ; g, pinion fitted to the other end of the shaft a, and communicating movement to another spur-wheel h, in front of vqhich is another toothed wheel i for a pitch-chain ; qn, drum of polygonal form keyed on to the shaft a, aud to which are attached the toothed defibrating-plates ; o, a double counter-plate, formed of two distinct parts : the front part is on the feed side, where the opening is wider, and its teeth project in the same direction as those of the drum, although inclined inversely, their object being to rectify the position of canes which are presented endwise ; the back or working counter-plate at the outlet side has teeth which project in the opposite direc tion, and effects the defibration of the canes, which it arrests and rolls on, crushing them under the teeth of the drum. The small quantity of resulting juice passes through little boles in the counter-plates, into the channel p, -whence it is conducted to the juice expressed by the cane-mill. The canes are fed by hand or by the carrier broadside-on upon the inclined plane which conveys them in front of the defibrator. The object of the ma chine is to prepare the cane for the ordinary cane-mill, by breaking up the fibres and knots lengthwise. It is stated that by its use the yield of juice has been increased from 70-71 to 78-82 per cent.
b. Bessemer's press.—An account of the cane-squeezing machine invented by H. Bessemer in 1849-52 is not necessary, as many such accounts already exist, and the machine never came into general use. Tln• macliine consi-ted of plungers working iu cylindere, across whose path the canes were passed endwise, and were thus crushed section by section. When applied to freshly-cut canes tbe W. Indies, the reeults fell short of the ordinary 3-roller cane-mill.