The still most commonly used in France for distilling brandy from wines, is known as the " Allegre" still, and is represented in elevation in Fig. 182, and in vertical section in Fig. 183. A B is the furnace ; E the boiler, which is partly enclosed in brickwork, and having an emptying cock F near the bottom. A try-000k g for ascertaining the level of the liquid in tho interior should be placed at about the height of the dotted line in the section. K is another try-cook for ascer taining the end of the operation ; at this point, the vapours emitted on turning the cook, will no longer take fire. L is another boiler, placed above tho previous one, fitted with an emptying cock DI, a try-cock o, and a small pipe n, which puts the two boilers in communication. Q is a plate separating the two boilers. In its centre there is a pipe r, surrounded by a series of concentric cylinders s t u and v, disposed as shown in the figure. These cylinders form a system by which the vapours of spirit and water are condensed at different temperatures and thereby effectually separated from each other ; the liquor formed is conducted away by thb pipe g q. The vapours from the boilers are thus made to travel through the spaces between these concentric cylinders, and finally pass out at the openings k k, coming again into contact with the liquor in L. A curved tube y, connected with the interior of the system, is filled with water, and permits the entrance of air in no of too sudden condensation. a is a try-cock corresponding to B in the boiler E. C is a manhole for the purpose of cleaning the boiler. The vapours from the upper boiler pass npwards into the circular rectifier e which rests upon the neck of the boiler L ; this vessel may be cleaned out by means of the opening at 1. Six compartments, op q r s o', arranged as shown in the figure, are placed above the rectifier e in the form of a column. Communication between these compart ments is established by means of the pipes l' ; besides this, the compartments are also connected by the small pipes I, 2, 3, 4, 5 and 6, which reach down to within 5 centimetres of the bottom of each, falling into a little trough similar to g g in the boiler E. U is a cylinder surrounding the column. The wine circulates in this, condensing and concentrating the ascending vapours, and afterwards escaping through r into the boiler L. S is a cistern containing the wine, which is run into the cylinder U by a little pipe f. Through another pipe the vapours escape from the column in order to condense, while the vapours from the cylinder U are led away through f" into the coils contained in the vats 5 and R. X is an outer covering to prevent the loss of heat by radiation. In grain distilleries, this is used for drying malt, which is placed in the interior. An opening at c, serves for the admission of water when it is required to clean the column.
The operation of distilling is performed by this apparatus in the following way :—A11 the cocks nre closed excepting those at o and g. The cooler R is filled with water, and tho cook at x" opened. The upper condenser S is filled with the wine to be distilled ; this condenser contains a coil iu which the vapours passing through f arc partially condensed, and which communicates by with the largo coil in the cooler R. When R is filled, the water is run through i into the boiler c, when it is made to boil by passing steam through the apparatus until the wine in S has reached a temperature of about 40°. The cock in the pipe c' is then opened to allow the wine to run from into the cylinder U, 5 being re-filled with cold wine. The cocks in the pipe h are then opened in order to allow tho water in the compartments of the column and in the rectifier to run out. 'These cocks are then clo-ed again, and the heat is diminished as far as possible, by means of a damper, to allow tho water to run out from the two boilers and from the rectifier by the cocks F M and h." While this is going on, the manholo I is opened and the boiler thoroughly cleaned out. This cleansing of the apparatus is not necessary every time that the process is interrupted, but only when the interruption is of some duration. When work is stopped for a length of time, the apparatus is loft full of water until the work is resumed. As soon as the hot water has run out, the cocks F, M, and h" are closed, and the lower boiler is filled up as far ss the cock g; g and I are then closed, and boat is again applied to the apparatus. When the water begins to boil, the boiler L is filled from the pipo r with tho wine previously heated in the cylinder U, up to the point o; o and r are then closed, and c' is opened in order to refill U with the contents of the cistern S. The water in E soon begins to boil, and the steam generated heats the lower part of the boiler L, and passing up r, around the cylinder, and out at k k, it passes through the wine into the upper part of L. The wine is thus gradually heated to the boiling point, and the vapours given off are led by i into the rectifier e, where it is partly concentrated ; the remainder passes into the upper column by the pipes 1'1'1'. Here the chief part of the condensation is carried on ; as the vapours gradually rise they are de prived of water, until they ultimately find their way through f into the coil contained into the cistern 5, and from that into the cooler R, where they aro comphtely condensed. The finished spirit is run out at m'.
The weak liquors from the several compartments of the upper column return through the pipes numbered 6, 5, 4, 3, 2, 1, until they reach the boiler L. The whole operation, as above described, occupies three hours ; but when the apparatus has become properly heated in all parts, two hours only are required.