Improvements in Furnaces for Concentrating Sulphuric Acid.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Furnaces for Concentrating Sulphuric Acid.
I, CHARLES NÉGRIER of 16, Ruo Drouot, Paris in the Republic of France,
Eagineer, lo 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 :-
My invention has for its object a furnace for effecting the concentration of
sulphuric acid at 66 degrees Beaumé without the use of platinum, at present
employed, the high price of which necessitates a hoavy expenditure in first cost of
plant.
To facilitate the understanding of the Specification, reference will be made to the
accompanying drawing which is attached by way of a specimen only.
Figure 1 is a longitudinal elevation of my apparatus.
Figure 2 a transverse elevation.
Figuro 3 a longitudinal section of the apparatus on the line A B of Figure 4 which
latter represents a top plan view.
The same letters of reference represent the same parts in all the various
Figures.
The apparatus consists essentially of two ranges of porcelain basins C in a series
of steps (en cascade) in such manner that the liquid escaping from the mouth of
one basin falls into the mass of liquid which is contained in the basin below.
These basins are supported by shelves of iron D which can carry each two basins
and which are themselves sustained on each sido by a series of projections resembling
in side view a narrow staircase formed in the masonry. These shelves are pierced in
the bottom with five holes to permit of the escape of the liquid in case of rupture.
Between each basin and its stand interpose a permeable asbestos tissue for the
purpose of assuring the stability of the basins and preventing them cracking in case
of violent ebullition, and as a measure of precaution 1 place sometimes in the basins
fragments of porcelain to facilitate the ebullition without spurting. The shelves
ought to be placed without actually touching each other, a space being left between
tbem for expansion of about three millimetres.
The fire is situated under the last shelf and its centre under the projection of the
geometric centre of that shelf, and at the height of the second shelf the gas and
the flame are conducted over an inclined plane in the direction of the arrows m in
such manner as to diminish as much as possible the distance between the shelves and
this inclined plane.
The gas of the fire is isolated from the upper part of the apparatus by means of
unions or joints with which the shelves are provided. Between the joints there is
placed moreover a mastic or cement of powdered asbestos, or of silicate of soda and of
powdered asbestos. After placing the basins in position, the shelves are covered
with a layer of coarse sand levelled off to the upper edge of the basins which are
furnished each with two heels or projections for preventing the play caused by the
expansion of the mass from bringing the basins and the upper shelf into contact. In

page_text: this way all the play resulting, whether from the heat or from the swelling of the
masonry, will in no wise influence the netion of the apparatus which remains regular
in spite of these destructive causes.
All the masonry situated above and starting from the level of the shelves is
in siliceous bricks (briques de grès). The cover S is made of plates of iron or of
glase.
The apparatus thus described works in the following manner :—
The neid to be concentrated, being placed in the reservoir a arranged at the top
of the apparatus, is brought by the two syphons at upon the slab from which
it rurs in the direction of the arrows into the first upper basin (where it
commences to heat and to concentrate. It escapes from there successively into
each of the other basins and runs out absolutely concentrated at the lowest
part at Z.
The neid vapours caused by the concentration follow the direction of the arrows?
and are aspirated by a tuyère of lead V placed at the height of the second shelf
(from the top). The aspiration is effected by a jet of steam or in any other
manner.
What small amount of water results from the use of steam can be condensed or not
according to the use to be made of it.
The hot gases follow the direction of the arrows m and leave the concentration
furnace at X, they are utilised for the formation of acid at sixty degrees Beaumé
either in an apparatus analogous to this one or in lead shelves lying on plates
of iron.
The apparatus such as has been described delivers the acid at sixty degrees Beaumé
to the extent of about 90 or 1000 kilogrammes per 24 hours, and of a remarkable
limpidity owing to the successive decantations. It consumes about 130 kilogrammes
of coal per 1000 kilos. of acid produced. One can obtain the acid at 661 degrees
without any difficulty.
In conclusion I reserve the right of varying the dimensions of the proportions and
number of parts employed in the construction of this furnace and of the material as I
may think convenient, as all these can be varied very materially without injuring
substantially the working apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is :-
The new or improved furnace for concentrating sulphuric acid characterised by the
combination of two rows of basins in porcelain arranged in a series of steps (en
cascade) in such manner that the liquid escaping from the mouth of one shall fall into
the mass of liquid in the basin immediately below, these basins being supported by
iron shelves pierced with holes and covered with asbestos for sustaining them in an
elastic manner, and receiving directly the action of the furnace gasos, whilst the acid
vapours caused by the concentration escape to the exterior by a conduit formed for
this purpose substantially as described above and illustrated by way of example in the
drawings annexod.
Dotad this Brd day of Sontombar 1890.
of Sontombar 1890.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.