Improved Method and Apparatus for Concentrating Sulphuric Acid.
Year: 1890

page_text: Date of Application, 17th Mar., 1890
Complete Specification Left, 27th June, 1890-Accepted, 21st Feb., 1891
PROVISIONAL SPECIFICATION.
Improved Method and Apparatus for Concentrating Sulphuric Acid.
I CHARLES SICAire Négrier of 16 Rue Neuve des Jacobins, Périgueux in the
Republic of France, Manufacturer do hereby declare the nature of this invention to
be as follows :—
This invention relates to the concentration of sulphuric acid in the manufacture
thereof. For this purpose in the space above the range of hearths is partitioned off*
a chamber the floor of which is on an inclined plane which is adapted to be heated
by the acid vapours etc. rising from said hearths. This floor or plane consists of a
number of plates of iron of suitable thickness formed each with a number (preferably
four) of hemispherical depressions or basin like cavities, and placed together and
supported on suitable walls so that the vapours and fumes from the hearth cannot
escape upward between said plates into the space above the latter. The cavities
are provided with small holes plugged with clay, these being necessary for preserva-
tion of the plates. The walls supporting the plates are made so as not to interfere
in any way with the proper working of the hearth.
The aforesaid cavities are intended to hold vessels of porcelain, glass or other
non-corrodible material cach having a lip projecting over the next below in series
on the inclined plane the incline of which depends upon the number of vessels.
The sulphuric acid is passed into the uppermost vessels and trickles over into the
next and so on through the series until it overflows from the last in a more or less
concentrated state into a suitable duct, which, if necessary is provided to carry it to
the concentrating chamber proper which is constructed with an inclined plane and
vessels on the same system. After suitable concentration the sulphuric acid passes
into a leaden receiver where it is cooled. The shape of the depressed cavities in
the plates may be of any other shape than hemispherical if desired.
The vapours arising from the acid as it is concentrated may be allowed to escape
into the air, but this entails loss of steam and of acid vapour; according to this
improved process the said vapours are carried into a leaden receiver and from
there into another leaden receiver which latter receives the products of several
systems, and like the first is intended for cooling the vapours. The vapours are
then carried into the principal lead chamber by means of an injector at slight
pressure the latter being regulated carefully at the commencement of the operation
to draw off the vapours etc. in proportion to their formation.
Dated this 17th day of March 1890.
HERBERT & CO.,
Agents to Applicant.
COMPLETE SPECIFICATION.
Improved Method and Apparatus for Concentrating Sulphuric Acid.
I CHARLES SICAIRE NÉGRIER of 16 Rue Neuve des Jacobins, Périgueux in the
Republic of France, Manufacturer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
This invention relates to the concentration of sulphuric acid in the manufacture
thereof. For this purpose above the range of hearths is arranged an inclined
plane which is adapted to be heated by the sulphuric acid vapours etc. rising from
said hearths. This plane consists of a number of plates of iron of suitable thickness

page_text: formed each with a number (preferably four of hemispherical depressions or basin-
like cavities, and placed together and supported on suitable walls so that the
vapours and fumes from the hearth cannot escape upward between said plates
into the space above the latter. The cavities above mentioned are provided with
small hole plugged with clay, these being necessary for preservation of the plates.
The walls supporting the plates are made so as not to interfere in any way with
the proper working of the hearth.
The aforesaid cavities are intended to hold vessels of porcelain, glass, or other
non-corrodible material each having a lip projecting over the next below in series
on the inclined plane the incline of which depends upon the number of vessels. The
sulphuric acid is passed into the uppermost vessels and trickles over into the next
and so on through the series until it overflows from the last in a more or less concen-
trated state into a suitable duct which, if necessary, is provided to carry it to the
concentrating chamber proper which is constructed with an inclined plane and
vessels on the same system. After suitable concentration the sulphuric acid passes
into a leaden receiver where it is cooled. The shape of the depressed cavities in
the plates may be of any other shape than hemispherical if desired.
The vapours arising from the acid as it is concentrated may be allowed to escape
into the air, but this entails loss of steam and of acid vapour; according to this
improved process the said vapours are carried into a leaden receiver and from there
into another leaden recriver which latter receive the products of several systems,
and like the first is intended for cooling the vapours. The vapours are then carried
into the principal lead chamber by means of an injector at slight pressure the latter
being regulated carefully at the commencement of the operation to draw off the
vapours etc. in proportion to their formation.
system is applicable to all furnaces, both for the powder sulphur or rocky
pyrites or to other systems connected therewith.
In the accompanying drawings:
Fig. 1. is a plan view of the furnaces connected together, the covering plates
removed.
Fig. 2. concentration-furnace, showing three hearths and a longitudinal section
thereof.
Fig. 3. illustrates the arrangement of the basins.
Fig. 4. is a longitudinal section of the flues.
Fig. 5. is a longitudinal section of the basins.
Fig. 6. is a longitudinal section of the porcelain duct.
Fig. 7. is a section of the refrigerator.
Above the range of the furnaces is placed the inclined floor A, the inclination of
which, according to the size of the globes, is for the system here set forth;
0.118 per meter (Fig. 4).
The walls B intended to support this floor are constructed in such a manner that the
sulphuric gases travel over the largest possible surface and they are arranged so
that the gases escaping from the ovens do not interfere with each other.
A double result is thus obtained: the cooling down of these sulphuric gases as
much as possible and the utilization of the heat therein.
On the aforesaid walls are placed iron plates D Fig. 3 of about 0.62 centimeters
long by 0.70 centimeters wide.
These plates are lapped over at their edges as shown (Fig. 3), in order to avoid
the escape of gases as far as possible. Each plate has four almost hemispherical
hollows D', which are intended to support the porcelain basins E Fig. 3. Each of
the hollows has the shape of a basin. Each hollow perforated with several holes
of about one centimeter diameter, which are necessary for the duration of the plate
and to avoid a breaking of the plate under heat.
Each plate being on the same line as the one in front and behind, a straight row
of basins is thus obtained coinciding with the line of greatest inclination. The
perforations in the basins are stopped up with clay-plugs, which give way to the
expansion and suffices to prevent the escape of the gases.

page_text: It is necessary that the spout of each basin overlaps the next basin sufficiently to
prevent the hot acid-drop from falling upon the cooler porcelain.
In case of an accidental breaking of one of the basins, the acid is absorbed by
the sand in the hollow cavity and detained in the iron plate, and a change may be
made without interrupting the motion of the apparatus.
The number of basins may vary and depends upon the degree of concentration to
be obtained. It is preferable not to exceed the number of twelve basins on each
row. By this method acids may be obtained the degree of which varies at a
temperature of 15° Centigrade from 60° to 64°; it is preferable not to push the
concentration further, evaporation being scarcely sensible after the acid has been
concentrated to 63°; but the working can be easily regulated by increasing the
flow in the series of basins.
The last basins pour out the acid at 63° into the porcelain duct F, which carries
it to the concentration furnace. The duct is constructed as indicated by Fig. 6
this arrangement permits an almost horizontal flow of the acid, without fear of
overflow.
The concentration furnace G¹ Fig. 2 is itself also an application of the same
method; the three hearths ggg are arranged below plates with 7 to 8 hollows,
forming with the basins which they support a descending plane touched by the fire,
which is vertical.
It requires a slow coke fire and without any draught. The acid concentrates up
to 66.25° (as estimated at a temperature of 15° C.). It then flows into a leaden
refrigerator R (Fig. 7) of any suitable construction consisting of chambers or
passages where a vigorous circulation of cold water brings it down to a tempera-
ture of 20 to 30° and it is collected in a continual manner in the condensing tub.
The shape of the hollows and basins is immaterial; the substance of the basins
may be of glass as well as of porcelain.
The covering plates are made of cast iron and joined with clay. The steam
issueing in this furnace may be allowed to escape into the atmosphere, but there is
thus a loss of a quantity of steam equal to of that necessary for the manufacture
of the acid and also of acid vapors carried along and which condense in drops of a
strength of 12 to 13° Baumé.
With my apparatus these vapors are carried by a leaden pipe I of 12% diameter
(Fig. 1) and taken into a leaden refrigerating reservoir J; and upon their escape
from the reservoir, they enter another reservoir also intended for refrigerating, but
which serves also as a reservoir for the vapors of several furnaces, then upon the
escape from this reservoir these cold vapors enter the leaden chamber H.
The vapors cannot enter the latter in consequence of the inner pressure of the
gases of the chambers, without using a thin vapor-jet and under weak pressure
capable of causing a slight impulse and if the latter is too strong outer air is
admitted into the chambers, which is bad, if it is insufficient, the concentrating ovens
get empty. This apparatus is regulated by moving a nut or sleeve M on the pipe L
conveying the steam to the jet, said pipe having a longitudinal orifice for escape of
the steam, which orifice is thus more or less closed by moving the nut endways on
the pipe L until the necessary result is obtained, namely motion of the acid
vapors as formed towards the chamber H.
This regulating is obtained at the moment of starting the process and once
established, it is settled.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1.) The method of concentrating sulphuric acid by passing the acid through a
series of basins over the producing furnace previous to its treatment in the concen-
trating furnace proper.
2.) The apparatus consisting of plates with hollows and basins therein arranged
in the furnaces in the manner and for the purpose set forth.

page_text: 3.) The method and apparatus for carrying the acid vapors and steam, which are
products of the concentration of the acid, from the spaces about the condensing
vessels into the lead chamber, substantially as and for the purpose set forth.
Dated this 27th day of June 1890.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.