Should any spirit rise in the wash-heater during the above operation, it will be carried down to the worm by the neck p, and coiled pipe, and discharged at its lower end; or it may be passed into the still-head, as shown in [fig. 1062.]
A patent was obtained by Mr. Æneas Coffey, in August, 1830, for a still, which has been since mounted in several distilleries. It is economical in fuel, labour, and time, but is said not to produce a clean spirit, without peculiar attention.
The apparatus is represented in [fig. 1067.] a, b, c, d, is a sectional view of that part of the still wherein the wash is deprived of its alcohol, and the vapours analyzed. It is described as consisting of a chamber or vessel a, with the vertical chamber b, c, placed above it; the lower half of this chamber is divided into compartments by horizontal plates e, e, e, of thin copper or other metal; each of these plates is turned down at one side, until it nearly touches the plate next underneath it, as shown in the figure; thus leaving a passage throughout the whole of them, by which any liquid falling on the top plate may descend into the next under it, and from that to the third, and so on, from plate to plate, at the alternate ends, until it arrives at the last plate, wherein it falls into the vessel a, by the pipe f; each of these plates is furnished with several light valves, opening upwards, through which any steam or vapour may ascend; it may also be perforated with holes, but they must not be so numerous or so large as to allow of all the steam passing through them without raising the valves; c, is a pipe by which the alcoholic vapour, after it has been analyzed, and has acquired the proper strength, is conducted into the vessel d, which is made perfectly close; the vapour will here be condensed on the surface of the pipe g, g, g; from this chamber it will descend in a liquid state into the pipe h, whence it may be conducted to a worm or refrigerator, to be cooled in the ordinary way; i, is a vessel through which the spent wash flows, after being operated upon in the distilling apparatus, and is discharged in a state of ebullition; j, is a vessel or chamber containing the wash to be distilled. A force pump may be substituted, to force the wash through the pipes k, and distilling apparatus, with the velocity required.
The patentee states that it is requisite the wash should be passed through the pipe k, with sufficient velocity and force, so as to prevent the deposition of sediment in the pipe; the wash in its passage through the pipe k, will gradually become increased in temperature as it passes through the spent wash in the chamber, and the close vessel d, until it is discharged nearly at the boiling point on the upper plate in the chamber, where it comes in contact with the vapours arising from the vessel a.
It is to be observed, that the wort does not reach the boiling point while in the pipe k, k; to ascertain which, a thermometer is placed on the pipe, and by increasing or diminishing the quantity of wash, its temperature may be regulated. The wash, after being discharged from the pipe k, descends from plate to plate as before mentioned, at which time a supply of steam from a boiler, or generator is admitted into the apparatus, through the pipe.
The lower part of this pipe in the vessel a, is pierced with a number of small holes, so as to spread the steam over the vessel; it then rises upwards, passing through the plate by the small holes and valves, and through the stratum or sheet of wash flowing over them; the wash, as it descends, gives out a portion of its alcohol to the steam, as it passes over every plate, until it is entirely deprived of its spirit, which it will generally do by the time it arrives at the 7th or 8th plate; but it is better to employ a greater number, to guard against accidents or neglect.
A small steam pipe rises from the chamber a, with its upper end opening into the box or chamber; into this chamber the end of a worm projects from the cistern of cold water; the steam rising up the pipe is nearly all condensed in the worm, and flows back into the chamber a, by the pipe. The small portion of the steam uncondensed, is allowed to escape at the upper end of the worm, and the flame of a small lamp or taper is to be constantly kept over the orifice; when, should the least quantity of alcohol descend with the wash into the chamber a, it will rise with the steam through the pipe and worm, and immediately take fire from the flame of the lamp or taper, thereby warning the attendant to increase the supply of steam or diminish the quantity of wash, as may seem necessary.
