IMPROVEMENTS IN EVAPORATING BRINE AND OTHER LIQUIDS, AND IN DISTILLATION
Year: 1855

page_text: PROVISIONAL SPECIFICATION left by Charles William Siemens at the
Office of the Commissioners of Patents, with his Petition, on the
7th November 1855.
I, CHARLES WILLIAM SIEMENS, of the Adelphi, do hereby declare the nature
of the Invention for "IMPROVEMENTS IN EVAPORATING BRINE AND OTHER LIQUIDS,
AND IN DISTILLATION," to be as follows:-
According to my improvements, the evaporation of brine, of saccharine or
other liquids, is effected by exposing the said liquid in a covered pan with a
double bottom to the influence of a circulating current of a permanent gas, in
such a manner that the said current passes in a zig-zag or circular manner
along the surface of the evaporating liquid, commencing at the end opposite
the source of heat and advancing towards the heated end; at certain intervals
portions of the current descend into the double bottom below the liquid, and
return towards the cooler end of the pan, passing finally through a condenser
or chamber containing a series of pipes filled with the cold liquid; the current
is urged by means of a propeller or fan to pass again over the surface of
the evaporating liquid, as before described. The source of heat consists of
one or more steam boilers and furnaces. The steam generated in the boilers
passes first of all either partially or wholly through an engine (which I prefer
to consist simply of a reaction wheel), in order to produce the necessary power
for working the fan pumps or other machinery.

page_text: The steam next enters one or more steam chambers or system of tubes in
contact with the evaporating fluid at the extremity of the pan opposite the
entry of the circular current, where it condenses in boiling the 'liquid, and the
water of condensation is forced back into the steam boilers. The fire, after it
leaves the steam boilers, passes through a system of flues, made of metal or
pottery, that cover the entire length of the pan, above the evaporating liquid,
and finally reaches the chimney. The rationale of the working of this
apparatus is as follows:-The current of permanent gas on entering the pan
commences to absorb vapour from the evaporating liquid. This absorption
would, however, soon cease if the current in its onward motion did not
encounter warmer liquid, and if it was not besides heated continually by the
flues that traverse the whole apparatus. By this process of gradual absorp-
tion the current will attain a high state of saturation with vapour before it
lescends into the double bottom of the pan. On its return towards the
cooler end of the apparatus, the vapour previously absorbed will be gradually
re-condensed on the bottom of the pan, and in rendering its latent heat to the
liquid above, will continue to support the evaporation of the same without
uccessitating a fresh supply of fuel. The permanent gas employed to con-
stitute the circulating current may be common atmospheric air; but I prefer
to use atmospheric air deprived of its oxygen, by being passed over incandescent
coal and quick lime, to prevent the chemical action of the oxygen upon the
inetallic parts of the apparatus, or upon the evaporating solution itself. The
rapidity with which a permanent gas absorbs vapours increases also inversely
with its specific gravity; I therefore prefer to employ hydrogen gas when it is
practicable. If the pan is used for evaporating strong brine, I give the same
a considerable length, and render both sides of the apparatus easily accessible
for the purpose of drawing the salt. For this purpose, cast-iron troughs are
screwed against the open sides of the pan, of sufficient depth to contain the
liquid. Along the outer edge of the troughs runs a groove, in which shutters
are made to slide, which close the sides of the apparatus, except where the
salt is being raked out. Several such pans may be put ono above the other,
and the upper ones may be raked by providing travelling stages for the men
to stand upon.
In many cases it will be found preferable to divide a single
pan into several equal sections, and arrange the same the one above the other.
The same apparatus may also be advantageously employed when suitably
modified for the distillation of water, or for separating alcohol from its watery
admixtures.
In adapting my improvements for the purpose of rectifying spirits, I
Arrange the apparatus in section one above the other. The liquid to be

page_text: distilled is put into the lower compartment, and is heated by means of steam
pipes or chambers; the mixed vapours which arise pass over inclined
surfaces arranged one above the other, over which a mixture of spirit and
water that are condensed in the upper portion of the apparatus penetrate.
The current of mixed vapour (in which the vapour of alcohol takes the
part of the permanent gas), in simply evaporating a solution, is thereby
rendered richer in vapour of alcohol, whereas a portion of its watery
vapour is condensed and returned to the lower compartment. The usual
current passes next under the bottom of an upper pan filled with a mixture
of spirits and water, that are condensed at an inferior temperature in an upper
portion of the apparatus. The liquid being already in a great proportion
alcohol, will be partly re-evaporated, whereas a portion of the vapour contained
in the ascending current condenses and returns to the lower chamber. The
combined current then ascends into another section of the apparatus similar
to the last, where another condensation chiefly of the watery portion takes
place, and the operation may be repeated several times, until the current
consists almost exclusively of alcoholic vapour. It thereupon passes through
a coil of pipe that is surrounded by cold liquid intended for distillation, where
the condensation of the alcohol takes place.