The above plan of a water-bath regulated by the thermostat, may be used simply as a rectifying cistern, without transmitting the spirit or wash down through it. The series of shelves will cause the vapours from the still to impinge against a most extensive system of metallic surfaces, maintained at a steady temperature, whereby their watery and crude constituents will be condensed and thrown back, while their fine alcoholic particles will proceed forwards to the refrigeratory. Any ordinary still may be readily converted into this self-rectifying form, by merely interposing the cistern, [fig. 1058.], between the alembic and the worm-tub. The leading novelty of the present invention is the movable system of shelves or trays, enclosed in metallic cases, separated by water, combined with the thermostatic regulator. By this combination, any quality of spirits may be procured at one step from wash or wine, by an apparatus, simple, strong and easily kept in order.
The empyreumatic taint which spirits are apt to contract from the action of the naked fire on the bottom of the still, may be entirely prevented by the use of a bath of potash lye, p, p, [fig. 1057.]; for thus a safe and effectual range of temperature, of 300° F., may be conveniently obtained. The still may also be used without the bath vessel.
Mr. D. T. Shears, of Southwark, obtained a patent in March, 1830, for certain improvements and additions to stills, which are ingenious. They are founded upon a previous patent, granted to Joseph Corty, in 1818; a section of whose contrivance is shown in [fig. 1062.], consisting of a first still a, a second still b, a connecting tube c, from the one end to the other, and the tube d, which leads from the second still-head down through the bent tube e, e, to the lower part of the condensing apparatus.
The original improvements described under Corty’s patent, consisted further, in placing boxes f, f, f, of the condensing apparatus in horizontal positions, and at a distance from each other, in order that the vapour might ascend through them, for the purpose of discharging the spirit by the top tube g, and pipe h, into the worm, in a highly rectified or concentrated state. In each of the boxes f, there is a convex plate or inverted dish i, i, i, and the vapour in rising from the tube e, strikes against the concave or under part of the first dish, and then escapes round its edges, and over its convex surface, to the under part of the second dish, and so on to the top, the condensed part of the vapour flowing down again into the still, and the spirit passing off by the pipe h, at top; and as the process of condensation will be assisted by cooling the vapour as it rises, cold water is made to flow over the tops of the boxes f, from a cock k, and through small channels or tubes on the sides of the boxes, and is ultimately discharged by the pipe l, at bottom.
[Fig. 1063.] represents a peculiarly shaped tube a, through which the spirit is described as passing after leaving the end of the worm at b, which tube is open to the atmospheric air at z; c, is the passage through which the carbonic acid gas is described as escaping into the vessel of water d.