AN APPARATUS FOR CON- CENTRATING AND DISTILLING SULPHURIC AND OTHER ACIDS, AND ALL SOLUTIONS IN GENERAL
Year: 1864

page_text: LETTERS PATENT to Eugène Alphonse Cotelle, of 29, Boulevart St. Martin,
Paris, Distiller Chemist, for the Invention of "AN APPARATUS FOR CON-
CENTRATING AND DISTILLING SULPHURIC AND OTHER ACIDS, AND ALL SOLUTIONS
IN GENERAL."
Sealed the 1st August 1864, and dated the 23rd February 1864.
PROVISIONAL SPECIFICATION. left by the said Eugène Alphonse Cotelle
at the Office of the Commissioners of Patents, with his Petition, on the
23rd February 1864.
I, EUGENE ALPHONSE COTELLE, of 29, Boulevart St. Martin, Paris, France,
Distiller Chemist, do hereby declare the nature of the said Invention for "AN
APPARATUS FOR CONCENTRATING AND DISTILLING SULPHURIC AND OTHER ACIDS, AND
ALL SOLUTIONS IN GENERAL," to be as follows:-
The difficulty and danger attending the concentration of sulphuric acid at
66 degrees Beaumé, except the apparatus be of platina, and the great expense of
the latter, has induced me to search for new means of attaining this result, which
are set forth in the present description. On the principle that apparatus of
stoneware may be used in the concentration of sulphuric acid were it not for
their fragility consequent on the temperature of the liquid they contain being
lower than the flame surrounding them, if the liquid be prevented from coming
in contact with the sides of the apparatus there would be no cause for their
breaking, whatever might be the temperature. This being understood, I

page_text: will now proceed to describe an apparatus for obtaining the desired result
which is represented in the annexed Drawing.
Fig. 1 is a central vertical section of the apparatus on line A, B., Fig. 2;
Fig. 2, a top plan of same; Fig. 3, a vertical section of part of the apparatus ;
Fig 4, a horizontal section on line E, F, Fig. 1; while Fig. 5 shows a hori-
zontal section on line G, H, Fig. 1. The same letters of reference indicate
like parts in the several Figures.
The apparatus is composed of a conical retort a placed vertically, the
smaller end uppermost, it is formed of compact refractory clay, the same as
that used for gas retorts, slightly modified, in order to form artificial stone-
ware. It is closed at bottom by means of an obturator b of concave form, and
having at its centre a hole for the escape of liquid under treatment. This
retort is nearly filled with pumice stone or other body uninfluenced by heat,
and proof against the action of the liquids being treated. This retort is closed
at top by an obturator c, having at its centre a small funnel-mouthed aperture
for the introduction of the liquid. This obturator is also furnished with a
pipe in communication with a stoneware refrigerator d, at the base of which
latter there is a pipe e also of stoneware for conveying the non-condensed
vapours into a chimney having a quick draught. As seen in the Drawings,
this pipe carries at the bottom part a small spout, through which the con-
densed liquid is returned to the retort. The pipe of lower obturator 6 of
the retort fits into the upper part of a leaden refrigerator f through which
the liquid passes before entering: the carboy g.. The retort is heated by a
furnace h, the flame of which circulates several times round the retort before
passing to the chimney. Above the furnace is mounted a reservoir i containing
the liquid to be treated. A pyrometer ; is placed at one part of the furnace in
view of the stoker, consisting of a bar of round iron in contact with the retort
and projecting from the furnace. The bar in expanding actuates an index
hand traversing a graduated arc, as shown. The minor details of construction
of the furnace will be sufficiently clear from the Drawings.
ACTION OF THE APPARATUS.
In order to explain the working of the apparatus it is necessary to consider
certain conditions as existing; thus I will suppose, first, that it is required to
concentrate acid at 66 degrees Beaumé, which acid is at 53 degrees as ordi-
narily produced. The retort being heated to a suitable degree (which point
is determined on the scale of the pyrometer by previous trial), the acid is
allowed to flow from reservoir i into the retort through the orifice at the centre
of the upper obturator. This acid falls on the heated pumicestone, which

page_text: retards its passage and affords time for it to become heated and run slowly to
the bottom of the retort. The acid in its passage meets with the more highly
heated layers and becomes more and more concentrated. The aqueous vapours
which then rise carry with them the sulphuric acid, and pass into the refri-
gerator d, which is exposed to the air; the acid condenses in this refrigerator
and returns to the retort, while the aqueous vapours are carried away by the
chimney. In this manner there will be no waste of acid, and but little loss
of heat, as the condensed acid returns to the retort at a very high temperature.
The condensed acid on arriving at the bottom of the retort passes into a refri-
gerator f, so as to prevent the great heat of the acid from breaking the
carboy g. It should be here remarked that the liquid acid does not touch
the sides of the retort, which is made for that purpose larger at bottom than
top, it is only the vapours forming that are in contact, which is not at all
comparable to the contact of a liquid owing to the differences of the tem-
perature, and consequently of expansion. What I have stated with reference to
the concentration of sulphuric acid also applies to other acids, the boiling
points of which are above that of water. The only difference is in the tem-
perature of the retort, which should be determined previously for each acid,
and marked by a point on the scale of the pyrometer. It is not, however,
necessary to calculate this temperature in degrees, as it is sufficient to know
where the hand on the dial should point for the operation to be well carried out.
I have now to consider the distillation of sulphuric acid with regard to
its purification. In this case the acid in reservoir i should be at 66 degrees,
while it is allowed to flow into the retort in such quantity that the whole is
vaporized before reaching the bottom. Further, if it escapes a little at the
bottom it may be again introduced into the reservoir. The vapours which rise
become condensed in the refrigerator, and instead of the condensed acid
returning into the retort as when simply concentrating it, it is conveyed by a
suitable channel into a reservoir or the ordinary receivers. In the case of
the concentration of a saline solution I dispense with the upper refrigerator
to allow of the free escape of the vapours. The solutional so flows from
reservoir i into the retort, and arrives at bottom at the desired density on
heine hosted autant

page_text: apparatus is that it may be used for treating any kind of acid or corrosive
liquors. The chief advantage consists, however, in its use for the concentration
of sulphuric acid, by means of which I am enabled to dispense not only with
platina apparatus, but also with the leaden boilers usually employed and
known as "preparers." Although I have mentioned 60 degrees as the limit 5
of concentration of the acid, it is unnecessary to say that this entirely depends
on the temperature. The same remark applies to saline solutions. The waste
heat, if any, escaping at the top of the furnace may also be utilized for various
purposes.
In conclusion, the principal features of the present Invention are,-
1st, the new principle observed in the apparatus used for the before-
mentioned purposes, which consists in having the vapours only, and not the
liquid itself, in contact with the sides of the retorts, thereby preventing the chief
cause of fracture of said vessels, viz., the difference in expansion.
1
2ndly, the application of this principle to the concentration of acids and 1
corrosive solutions, and for the distillation of all kinds of acids in general, by
gradually and regularly pouring the liquids to be distilled, concentrated, or
evaporated, on to subdividing bodies in the manner described.
3rdly, the peculiar arrangements of apparatus represented in the Drawing,
which may be used for the concentration or distillation in a continuous and 2
economical manner of all kinds of corrosive or other liquids.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Eugène Alphonse Cotelle in the Great Seal Patent Office
on the 16th August 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EUGÈNE :
ALPHONSE COTELLE, of 29, Boulevart St. Martin, Paris, France, Distiller
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of February, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Eugène Alphonse Cotelle, Her special licence that I,
the said Eugène Alphonse Cotelle, my executors, administrators, and assigns,
or such others as I, the said Eugène Alphonse Cotelle, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others, from 3
time to time and at all times thereafter during the term therein expressed,

page_text: should and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "AN APPARATUS FOR CONCENTRATING AND DISTILLING
SULPHURIC AND OTHER ACIDS, AND ALL SOLUTIONS IN GENERAL," upon the condition
(amongst others) that I, the said Eugène Alphonse Cotelle, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Eugène Alphonse Cotelle do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the fol-
lowing statement, reference being had to the Sheet of Drawings hereunto
annexed and to the letters and figures marked thereon (that is to say):―
The difficulty and danger attending the concentration of sulphuric acid at
66 degrees Beaumé, except the apparatus be of platina, and the great expense
of the latter, has induced me to search for new means of attaining this result,
which are set forth in the present description. On the principle that appara-
tus of stoneware may be used in the concentration of sulphuric acid were it not
for their fragility consequent on the temperature of the liquid they contain
being lower than the flame surrounding them, if the liquid be prevented from
coming in contact with the sides of the apparatus there would be no cause for
their breaking, whatever might be the temperature. This being understood
I will now proceed to describe an apparatus for obtaining the desired results,
which is represented in the annexed Drawing.
Fig. 1 is a central vertical section of the apparatus on line A, B, Fig. 2;
Fig. 2, a top plan of the same; Fig. 3, a vertical section of part of the appara-
tus; Fig. 4, a horizontal section on line E, F, Fig. 1; while Fig. 5 shows a
horizontal section on line G, H, Fig. 1. The same letters of reference indicate
like parts in the several Figures.
This apparatus is composed of a conical retort a, placed vertically, the
smaller end uppermost, it is formed of compact refractory clay, the same as
that used for gas retorts slightly modified in order to form artificial stoneware..
It is closed at bottom by means of an obturator 6 of concave form and having
at its centre a hole for the escape of liquid under treatment. This retort is
nearly filled with pumicestone or other body uninfluenced by heat, and proof
against the action of the liquids being treated. This retort is closed at top
by an obturator c having at its centre a small funnel-mouthed aperture for the

page_text: introduction of the liquid. This obturator is also furnished with a pipe in
communication with a stoneware refrigerator d, at the base of which latter
there is a pipe e, also of stoneware, for conveying the non-condensed vapours
into a chimney having a quick draught. As seen in the Drawings this pipe
carries at the bottom part a small spout, through which the condensed liquid
is returned to the retort. The pipe of lower obturator 6 of the retort fits into
the upper part of a leaden refrigerator f, through which the liquid passes
before entering the carboy g. The retort is heated by a furnace h, the flame
of which circulates several times round the retort before passing to the
chimney. Above the furnace is mounted a reservoir i containing the liquid to
be treated. A pyrometer is placed at one part of the furnace in view of the
stoker, consisting of a bar of round iron in contact with the retort and pro-
jecting from the furnace, this bar in expanding actuates an index hand
traversing a graduated are, as shown. The details of construction of the
furnace will be sufficiently clear from the Drawings.
ACTION OF THE APPARATUS.
In order to explain the working of the apparatus it is necessary to consider
certain conditions as existing; thus I will suppose, first, that it is required to
concentrate acid at sixty-six degrees Beaumé, which acid is at fifty-three
degrees as ordinarily produced. The retort being heated to a suitable degree
(which point is determined on the scale of the pyrometer by previous trial),
the acid is allowed to flow from reservoir i into the retort through the orifice
at the centre of the upper obturator, this acid falls on the heated pumicestone,
which retards its passage and affords time for it to become heated and run
slowly to the bottom of the retort. The acid in its passage meets with the
more highly heated layers and becomes more and more concentrated. The
aqueous vapours which then rise carry with them the sulphuric acid and pass
into the refrigerator d, which is exposed to the air; the acid condensed in this
refrigerator returns to the retort while the aqueous vapours are carried away
by the chimney. In this manner there will be no waste of acid and but little
loss of heat, as the condensed acid returns to the retort at a very high tempera-
ture. The condensed acid on arriving at the bottom of the retort passes into
a refrigerator f, so as to prevent the great heat of the acid from breaking the
carboy g. It should be remarked that the liquid acid does not touch the sides
of the retort, which is made for that purpose larger at bottom than top.
It is only the vapours forming that are in contact, which is not at all com-
parable to the contact of a liquid, owing to the difference of temperature and
consequently of expansion. What I have stated with reference to the con-

page_text: centration of sulphuric acid also applies to other acids the boiling points of
which are above that of water. The only difference is in the temperature of
the retort, which should be determined previously for each acid, and marked
by a point on the scale of the pyrometer. It is not, however, necessary to
calculate this temperature in degrees, as it is sufficient to know where the
hand on the dial should point for the operation to be well carried out.
I have now to consider the distillation of sulphuric acid with regard to its
purification. In this case the acid in the reservoir i should be already at 66
degrees, while it is allowed to flow into the retort in such quantity that the whole
is vaporized before reaching the bottom. Further, if it escapes a little at the
bottom it may be again introduced into the reservoir. The vapours which
rise become condensed in the refrigerator, and instead of the condensed acid
returning into the retort, as when simply concentrating, it is conveyed by a
suitable channel into a reservoir or the ordinary receivers. In the case of the
concentration of a saline solution I dispense with the upper refrigerator to
allow the free escape of the vapours. The solution also flows from reservoir i
into the retort and arrives at bottom at the desired density on being heated to
the requisite extent
The herein described apparatus may be arranged so as to heat several
retorts with a single furnace, thereby effecting a saving in the cost of construc-
tion and also in fuel and arrangement.
Fig. 6 shows an arrangement in which there are four retorts heated by a
single furnace. The advantage of this apparatus is that it may be used for
treating any kind of acids or corrosive liquors. Its chief advantage consists,
however, in its use for the concentration of sulphuric acid, by means of which
I am enabled to dispense not only with platina apparatus but also with the
leaden boilers usually employed and known as preparers. Although I have
mentioned 60 degrees as the limit of concentration of the acid, it is unnecessary
to say that this entirely depends on the temperature. The same remark applies
to saline solutions. The waste heat, if any, escaping at the top of the furnace
may also be utilized for various purposes.
In conclusion the principal features of the present Invention are,-
1st, the new principle observed in apparatus used for the before-mentioned
purposes, which consists in having the vapours only and not the liquid itself
in contact with the sides of the retort, thereby preventing the chief cause of
fracture of said vessels, viz., the difference in expansion.
2ndly, the application of this principle to the concentration of acids and

page_text: corrosive solutions, and for the distillation of all kinds of acids in general,
by gradually and regularly pouring the liquids to be distilled, concentrated, or
evaporated on to subdividing bodies in the manner described.
3rdly, the peculiar arrangements of apparatus represented in the Drawing,
which may be used for the concentration or distillation, in a continuous and 5
economical manner, of all kinds of corrosive or other liquids.
In witness whereof, I, the said Eugène Alphonse Cotelle, have hereunto
set my hand and seal, this Ninth day of August, in the year of 'our
Lord One thousand eight hundred' and sixty-four.