Improvements in the Method of and Apparatus for Concentrating Sulphuric Acid and other Liquids.
Year: 1892

page_text: Date of Application, 26th Oct., 1892-Accepted, 3rd Dec., 1892
COMIDDIN SIETEICATION.
Improvements in the Method of and Apparatus for Concentrating
Sulphuric Acid and other Liquids.
I, IVAN LEVINSTEIN, of "Hawkesmoor" Fallowfield, Manchester in the County
of Lancaster, Chemical Manufacturer, do hereby declare the nature of this inven
tion, 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 method of and to apparatus for concentrating
sulphuric acid and other liquids, its objects being to enable the process of concen-
tration to be conducted more economically than at present; to prevent the waste
and annoyance which arise from the escape of fumes generated during the process;
to obtain a highly concentrated product with less risk; to enable any necessary
repairs to the plant to be inexpensively and quickly effected; and to bring the
process under more immediate and easier control.
In apparatus constructed according to these improvements, and in conducting the
process of concentration by my improved method, the acid or other liquid is caused
to traverse a descending series of vessels exposed to a suitable source of heat.
Weak acid or liquor is supplied to the upper vessel or vessels, and flows thence into
and through all the succeeding vessels, leaving the lowest of the series in a
concentrated condition. This type of apparatus and method of concentration are
well known and have been in use for some time past, but are open to several
objections which I avoid.
In such apparatus hitherto, there have been two fires for the purpose of supply-
ing the heat necessary for the concentration, but as the draught of one fire has
interfered with that of the other it has been found impracticable to produce a
uniform controllable temperature. I have therefore, in order to avoid this defect,
arranged my apparatus with a single fire. In the concentration of sulphuric acid,
a considerable expenditure of fuel is necessary with, existing apparatus of this type,
for raising the weak acid to the required temperature for concentration and during
concentration. To avoid waste of fuel I heat the acid more effectively than
hitherto, by means of the waste heat from the concentrating plant, before it enters
the concentrating vessels. Should one of these vessels break at present, great
difficulty and waste of time are experienced in replacing it. Also, their construction
and arrangement do not permit the heated gases to act upon them completely,
particularly at or near the bottom. To remedy these and other defects, I construct
the vessels with rounded bottoms and embed each of them during use in a sand bath
contained in a suitable metallic basin. I also arrange that by turning any one of
the vessels through part of a rotation about its vertical axis, it may be lifted out of
the series clear of the spout of the upper vessel. Thus any one vessel may be lifted
out and replaced in a very short time and without materially interfering with the
process of concentration. To enable the temperature of the acid to be ascertained
continuously, I arrange one or more thermometers or pyrometers in the concentrating

page_text: '
chamber or in the acid itself but with their graduations outside so as to be constantly
visible so that the rectifier has the whole apparatus and the regulation of the
temperature under easy control.
The anhydrous fumes which leave the last vessel in the concentration of sulphuric
acid I absorb or condense in cool concentrated acid by surface contact.
This may
be effected by allowing the acid from the concentrating vessels to flow into a
water-jacketed receiver and causing the fumes to pass over the surface of the acid
therein.
Alongside or upon each side of the series of concentrating vessels, I arrange a
gutter or gutters to quickly carry away. any acid or liquor which may escape from
a broken vessel, and thus to avoid waste and fumes which may arise on such an
occurrence.
I will more particularly describe my said invention with reference to the
accompanying drawings in which :-
Figure 1 is a longitudinal section ;
Figure 2 a longitudinal section on an enlarged scale, of the receiver; and
Figure 3 a cross section of Figure 2.
Figure 4 is a longitudinal section of a modified arrangement of receiver.
Figure 5 is a plan, partly in section, of an apparatus containing two series of
concentrating vessels.
Figure 6 is a longitudinal section along the line a-y, Figure 4.
Figure 7 is a sectional elevation of the apparatus represented by Figure 5.
Figure 8 is a partial longitudinal section shewing the preliminary heating and
settling vessels.
Figure 9 is a partial longitudinal section shewing the construction and arrange-
ment of the glass concentrating vessels.
Figure 10 is a plan of one of the concentrating vessels.
Figure 11 is a section of a modified construction of concentrating vessels.
Figure 12 a front and side view respectively of one of the circulating tubes.
And
Figure 13 a cross section of the flue in which the concentration vessels are
arranged.
It is found generally more convenient in practice to construct the apparatus with
two sets or series of concentrating vessels parallel with each other as shewn by the
drawings.
A is the furnace which is erected at one end, the gases from which pass into the
two side flues B B. From these side flues, the hot gases pass through suitable
openings C C, into the central passage D, the floor of which is constructed in a
series of steps upon each of which one of the concentrating vessels E is placed.
The opposite end of the central passage opens into a chamber F, in which the
preliminary heating and settling vessel G is placed. From the furnace there is a
side flue leading directly to the chamber F, and controlled by the door or
damper G', so that in the event of one of the glass vessels being broken, the damper
may be opened, when the hot gases will pass direct to the chamber and cease to pass
through the side flues and central passage until the damper has again been closed
after the broken glass vessel has been replaced. A tank H is placed to one side
above the chamber F, with its bottom exposed to the heated gases. Dwarf
walls I may be erected in the chamber F for the purpose of deflecting the heated
gases upon or around the vessel G and the tank H. When two sets of the concen-
trating vessels are used, the tank H may serve for both sets, the acid issuing
therefrom to each series of vessels through a pipe J controlled by the cock or
valve J¹.
Each of the glass vessels is provided with a spout E' which when they are in use,
overlaps the edge of the next lower vessel so that the contents of an upper vessel
overflow into the next lower vessel. To promote the complete circulation and
mixture of the acid or liquid during its passage through the series of vessels, I cause
the overflow from one vessel to run into an open tube K, so that the fluid must pass

page_text: down to the bottom of the vessel and out from the top, as is already practised. To
prevent the choking of the lower end of the tube by an accumulation of sediment
or otherwise, I cut away one side of it as shewn by Figure 12 and I may also form
a hole K through which the liquid may still pass into the vessel should the sediment
reach above the cut away part of the tube. The upper part of each vessel is turned
out expanded or flanged as shewn so as to bring the upper edge well below the spout
of the higher vessel without bringing the vessels themselves too closely together.
At each side of the vessel (or only on one side if preferred) I flatten the expanded
or flanged part of the vessel as shewn by Figures 9 and 10 so that by turning the
vessel through about a quarter turn it may be lifted vertically clear off the spout of
the higher vessel. Instead of making the bottoms of the vessels flat as hitherto, I
form them rounded or hemispherical, and bed them in metallic basins L containing
sand.
The top of the central passage A, is formed by the plates M, a pair of which is
arranged for each of the concentrating vessels. The inner edges of these plates are
curved as shewn in Figure 5 so as to embrace the vessel. The joint between the
sides of the vessels and the plates M may be packed with asbestos M'. The hot
gases are thus limited to the middle and lower parts of the vessels, and their mouths
are open within the passage N into which the vapours of concentration rise, and
from which they pass through the pipes O into the trough or pipe P, in which they
may be condensed or through which they may be led for condensation into a
tower.
The basins L, have hooks or perforations lugs or the like, L', cast upon them
which may be engaged by suitable hooks or tools when it is required to lift one of
the vessels from the series.
At the lower end of the series of concentrating vessels, I place the receiver R,
which consists of an inner vessel Q contained within an outer vessel through which
cold water is circulated. The cold water may enter through the pipe r, and leave
by Figures 2 and 3. The inner vessel may, in the case of sulphuric acid, be con-
structed of lead, and is covered by the removable lead faced covers S S. The acid
or other liquid is delivered into the receiver from the lowest of the concentrating
vessels through the porcelain or other suitable tube T, and leaves it through the
tube U, at the opposite end. The tube U is bent downwards so as to take the
acid from the bottom, and it may deliver it direct into carboys or otherwise as may
be convenient. At the same end of the receiver I may arrange the upcast V, which
is not essential, but which is useful for the purpose of promoting a flow of the fumes
and vapours constantly in one direction over the surface of the cool concentrated
liquid. This pipe may communicate with the pipe or trough P'. The heavy fumes
and vapours which pass from the concentrating chamber through the tube T, fall
upon the surface of the cool liquid and are thereby condensed or absorbed.
case of sulphuric acid these fumes consist largely of anhydrous acid which is thus
In the
added to the concentrated acid and it is found in practice that practically no acid
vapours leave the receiver when in use.
If it be an objection to have concentrated cool sulphuric acid in contact with lead
in the receiver, I may arrange to receive the concentrated acid from the pipe T,
in a glass porcelain or platinum tube Y, Figure 4. This tube is arranged to pass
through the concentrated acid, and deliver its acid free from contact with that in
the receiver as shown. Instead of passing through its concentrated acid the
pipe Y may be arranged to pass through the water jacket or otherwise, and in
any case, arrange to keep the receiver supplied with concentrated cool acid
for the purpose of absorbing the fumes of anhydrous acid as already described.
Hitherto the side inlets from the flues to the central passage D, have been
arranged throughout the whole length, but I prefer to limit them to the lower
part of the passage where the greatest heat is required, as shewn by Figures 5 and 6,
and to arrange baffle plates C within them to prevent the direct impact of the hot
gases on the glass vessels. In one or more of the cover plates Z which close the
concentrating chamber, I arrange a thermometer or pyrometer X to indicate the

page_text: temperature. The rectifier can by a glance at the indication of this instrument tell
when to increase or diminish the intensity of the fire. It will generally be found
sufficient to employ only one such instrument as indicated in Figure 1.
In use, the acid or liquid to be concentrated is supplied to the tank H where it
is warmed by the waste heat and whence it runs through the pipe J, to the vessel G
in which its temperature is further increased. Thence it is conducted to the first of
the concentrating vessels.
Before starting the apparatus, the receiver is filled with cold concentrated acid
or liquid.
Along each side of the passage D, I construct a gutter W, for the purpose of
leading away any fluid which may escape from a broken concentrating vessel. The
lower ends of the gutter have their outlet in a cross gutter which may lead to a
suitable tank or receptacle.
The modified construction of the concentrating vessel illustrated by Figure 11
has been devised for the purpose of obviating the weakness of the bottom of the
vessel inseparable from the existing method of manufacture. Instead of blowing
the vessel from the bottom and thus producing there a lump of glass which has to
be cut away before the vessel is used, I blow it from the top, producing a more or
less bottle shaped vessel, in the upper end of which I form, upon one side the spout,
and upon the other side a hole through which the circulating pipe K may be
inserted and withdrawn. To remove one of these vessels from the series it is only
necessary to turn it so far as to remove the upper end of the tube K from under
the spout of the next higher vessel.
In the rectification or concentration of sulphuric acid by the method and means
hereinbefore described, I am enabled to take tower acid direct from the tower, and
run it out from the receiver continuously and safely at a strength of 170 Tw., a result
which cannot be obtained either by the use of platinum vessels or in retort firing at
present without very great risk.
I wish it to be understood that I am aware of the Specification of Webb's
Patent No. 2343, A.D. 1891 and I make no claim in this Specification to anything
described and claimed therein.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
1. The hereinbefore described method of concentrating sulphuric acid which
consists in effecting a preliminary heating of the acid by waste products of com-
bustion, evaporating it in a descending series of vessels exposed to heat, cooling the
acid in a receiver, and absorbing the fumes of anhydrous acid in the cooled acid,
substantially as and by the means herein before described.
2. In apparatus of the type described for concentrating sulphuric acid and other
liquids, concentrating vessels constructed with round or rounded bottoms and with
a flattened upper edge, of the shape shewn in Figures 9 and 10 substantially as
and for the purpose hereinbefore described and as illustrated by the accompanying
drawings.
3. In apparatus of the type described for concentrating sulphuric acid and other
liquids, the combination with the concentrating vessels of removable metallic basins
in which the vessels are embedded, and hooks projections or perforations in or
upon the basins by means of which they may be lifted substantially as berein-
before described.
4. In combination with apparatus for concentrating sulphuric acid, a. receiver
into which the acid flows immediately after concentration, in which it is cooled, and
to which also any fumes of anhydrous acid from the concentrating chamber may
have access, constructed aud arranged substantially as and for the purpose herein-
before described and as illustrated by the accompanying drawings.
5. In combination with apparatus for concentrating sulphuric acid, a receiver
containing cool concentrated acid for absorbing or condensing acid fumes, through

page_text: which or the water jacket surrounding which the freshly concentrated acid flows in
a glass porcelain or platinum tube, substantially as and for the purpose hereinbefore.
described and as illustrated by the accompanying drawings.
Dated this 22nd day of October A.D. 1892.
WILLIAM E. HEYS,
Agent for the Applicant.