IMPROVEMENTS IN CONCENTRATING SULPHURIC ACID, AND IN THE APPARATUS USED THEREFOR.
Year: 1877

page_text: LETTERS PATENT to Frederick William Kalbfleisch, of Brooklyn, King's
County, and State of New York, United States of America, at present of 449,
Strand, in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
CONCENTRATING SULPHURIC ACID, AND IN THE APPARATUS USED THEREFOR.'
"
PROVISIONAL SPECIFICATION left by the said Frederick William Kalbfleisch
at the Office of the Commissioners of Patents on the 25th April 1877.
FREDERICK WILLIAM KALBFLEISCH, of Brooklyn, King's County, and State of
New York, United States of America, at present of 449, Strand, in the County of
Middlesex. "IMPROVEMENTS IN CONCENTRATING SULPHURIC ACID, AND IN THE
APPARATUS USED THEREFOR.
"
My Invention comprises,-
First. A contrivance whereby the apparatus for heating and partly concentrating
the acid, preparatory to entering the still, is enabled to be constructed cheaper, and
is calculated to be more durable, and also more economical of the heat used
Second. A more economical construction of the platina still, both in respect to a
saving of the expense of material of which the still is made, and in the effectiveness
of the still.
Third. A more economical method of supplying the steam required in the leaden
chambers.
And, Fourth. A simple method of regulating the quantity of acid in the still, all as
compared with the apparatus now in use.
For the preparatory process, I make a flat steam box, say, three feet wide, by six
feet long, and two or three inches deep, the bottom and sides being preferably of
boiler iron, and the top of steel, the latter being to enable the heat to pass more
readily than it can through the thicker iron. On the top of this box, which may
be set in asbestos, cement, or any other approved non-conductor of heat, I lay a
shallow pan of sheet lead, platina, or any other suitable material; at the back of
this pan, and elevated somewhat above it, I place a leaden pan or box, open at the
top, and five or six inches deep, and of the same width as the shallow pan, and in it,
near the discharging side, is a partition extending from the top nearly to the bottom,
Price Gd1

page_text: and parallel with the side over which the acid flows, said side being a little lower
than the others, and having a shute or apron over which the acid flows into the
shallow pan. At the back of the partition I arrange a horizontal coil of lead pipe,
elevated somewhat above the bottom of the leaden pan or box, said coil being con-
nected at one end with the steam box, and at the other with a leaden chamber,
in which the acid is generated. At the other end of the steam box and shallow pan
I arrange a shallow still of platina, said still being rectangular or other suitable
shape on the bottom, and flat, or nearly so, on the top; at the discharging end, and
from which end it rises gradually towards the receiving end, and forms the dome
or capital thereat, for conducting the vapours into a pipe leading to a condensing
worm, usually employed in concentrating apparatus, which condensing worm I
elevate sufficiently high, so that the condensed vapours flow back direct into the
leaden chamber.
The interior of this still, which should be two or three inches deep on its side,
I divide, by soldering it to its sides, and also to its bottom, at intervals, one or more
plates of platina traversing it from side to side, and set edgewise to the bottom, said
plate or plates being so arranged that they reach nearly to the bottom, except at
intervals where they touch, for the purpose of being soldered thereto. The plate
or plates are employed for two purposes; first, to strengthen the bottom of the still,
which, on account of the great expense of the material, it is desirable to make as
thin as possible, and, second, to compel only the strongest acid, which by reason of
its greater specific gravity settles to the bottom, to flow uniformly over the bottom,
and to occupy the successive divisions, so that at the last division only the strongest
and most concentrated acid will run off at the discharge pipe.
For regulating the depth of acid retained in the still, I make the discharge pipe
with an arched section, and connect it to the still, so that it can be shifted around
to elevate or depress said section, and thus make the passage over which the
acid escapes higher or lower, as the case requires. The inlet pipe for the acid is
diagonally opposite to the outlet pipe, thus ensuring the best results in respect to
the application of the heat to the acid in the still, and also enabling another still to
be connected thereto should occasion require.
The still is placed on a steam box, (which is similar to the steam box before
described), which is connected by a pipe with the steam boiler, and which is also
connected with the first described box by a pipe; and under this steam box may be a
furnace for superheating the steam in it.
In using the apparatus, sufficient acid is run from the leaden chamber into the
pan or box to fill it and to cover the bottom of the shallow pan and the bottom of
the still, then the steam is let into the box and a fire lighted in the furnace under
it to superheat the steam. From this box the steam passes into the steam box,
thence through the leaden coil of pipe in the leaden pan or box, and finally it dis-
charges into the leaden chamber, where after being cooled in the leaden pan or box,
by giving off its heat to the acid, and thus producing a useful effect, by cooling it
supplies the aqueous vapour required for generating the acid in the leaden chamber
cheaper than when made especially for that purpose, as in the ordinary method.
The acid, which is first heated in the pan, passes down under the partitions, which
prevents the heavier portion from remaining in the box, and so flows on to the
shallow pan, where it is concentrated to about 60° Beaume, and from there it flows
into the still where it is concentrated to 66° Beaume.
Heretofore the shallow pan and the still have been placed over furnaces for being
heated, by which the leaden pan is often overheated and melted, as the heat required
to concentrate the acid is nearly up to the melting point of lead, and at best the
furnace heat is irregularly distributed, whereas by the steam heat the distribution
is uniform. The furnace heat is sometimes injurious to the platina still by a
glazing effect it has on the bottom, which renders the metal brittle, and prevents the
passage of heat as readily as it otherwise would.
By the contrivance of the dome of the still at the end where the acid enters,
and where the greater volume of vapour arises and escapes, and by contracting

page_text: therefrom toward the other end, two important advantages are gained, viz., the
volatile matters are more quickly separated from the more concentrated portions, so
that the contact of the latter with the former is less as it flows along towards
the escape or discharging passage, thus facilitating the separation, and by so tapering
the top a considerable economy of material is effected, as compared with the ordinary
round conical dome-shaped still.
The equal application or distribution of the steam heat to the shallow pan, together
with the facility of maintaining it uniformly at the highest degree of temperature
consistent with safety to the lead pan, permits a much smaller evaporating pan to
be used, and avoids the necessity of employing means to control the flow of the acid
from one portion of a pan to another, through a series of pans, as when fire heat is
used.
As compared with the cost of the ordinary apparatus of the same capacity, this
can be made for about one-third of the cost of the other, while it will be much more
durable and effective.
The furnace may, if preferred, be used in direct contact with the still without the
steam box, in which case, the pipe by which the steam is supplied will be attached
directly to the box first described.
As the steam will be too hot, when leaving the steam box, to be used safely under
the leaden pan, air or other steam of lower temperature may be introduced into the
first-named box along with it, which will afford means for regulating the tempera-
ture exactly as required.
In regard to the form of still, as above described, and the location of the inlet
pipes, and the pipe by which the vapors are conducted to the condenser, relatively
to the still so shaped and to each other, I may state that very considerable advan-
tages are obtained,-
First. Because by the location of the beak or pipe leading to the condenser,
being directly over the inlet, which is the place where the largest proportion of the
vapor rises the passage of the vapours to the beak is more direct, and with less
contact with the surface of the still, so that less space is required to carry it off, and
there is less condensation by surface contact; also that which does condense and
drops back into the acid, falls into that which is less concentrated, and therefore more
readily and cheaply thrown off again.
And, Second. By this location of the inlet and the beak, the sloping or contracting
form of the still is permitted because there is less vapour rising from the more con-
centrated acid passing on to its outlet, which form effects a considerable economy of
the very expensive material of which the still is made.
Although I have described this apparatus in detail, yet my Invention must not be
considered as confined to the use of any particular apparatus, but embraces the use
of the process, substantially as herein described.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick William Kalbfleisch in the Great Seal Patent Office on
the 25th October 1877.
"
FREDERICK WILLIAM KALBFLEISCH, of Brooklyn, King's County, and State of
New York, at present residing at 449, Strand, in the County of Middlesex.
IM-
PROVEMENTS IN CONCENTRATING SULPHURIC ACID, AND IN THE APPARATUS USED
THEREFOR."
My Invention comprises,-
First. A contrivance whereby the apparatus for heating and partly concentrating
the acid preparatory to entering the still is enabled to be constructed cheaper, and
is calculated to be more durable, and also more economical of the heat used.
Second. A more economical construction of the platina still, both in respect to a

page_text: Figure 1 is a longitudinal sectional elevation of my improved apparatus ;
Figure 2 is a top. view; Figure 3 is a longitudinal section of the still, and Figure 4
is a transverse section.
For the preparatory process I make a flat steam box (A), say three feet wide by
six feet long, and two or three inches deep, the bottom and sides being preferably
of boiler iron and the top of steel, the latter to enable the heat to pass more readily
than it can through the thicker iron. On the top of this box, which may be set in
asbestos, cement, or any other approved non-conductor of heat, I lay a shallow
pan (B) of sheet lead, platina, or any other suitable material. At the back of this
pan, and elevated somewhat above it, I place a leaden pan or box (C) open at the
top and five or six inches deep, and of the same width as the shallow pan B, and in
it, near the discharging side (D), is a partition (E) extending from the top nearly to
the bottom, and parallel with the side over which the acid flows, said side being a
little lower than the others, and having a shute or apron (F), over which the acid
flows into the shallow pan B. At the back of the partition E, I arrange a horizontal
coil (G) of lead pipe, elevated somewhat above the bottom of the leaden pan or
box C, said coil being connected at one end with the steam box A, and at the other
with the leaden chamber H in which the acid is generated. At the other end of
the steam box A and shallow pan B, I arrange a shallow still (I) of platina, said
still being rectangular or other suitable shape on the bottom, and flat or nearly so
on the top at the discharging end, from which end it rises gradually towards the
receiving end and forms the dome with capital thereat for conducting the vapours
into a condenser (K) usually employed with concentrating apparatus, which con-
denser I elevate sufficiently high (as shown in Figure 1), so that the condensed
vapours flow back direct into the leaden chamber H.
The interior of this still, which should be two or three inches deep, I divide by
soldering to its sides and also to its bottom at intervals, one or more plates (L) of
platina, traversing it from side to side, and set edgewise to the bottom, said plate or
plates being so arranged that they reach nearly to the bottom, except at intervals
where they touch and are soldered thereto. The plate or plates are employed for
two purposes, first, to strengthen the bottom of the still, which on account of the
great expense of the material it is desirable to make as thin as possible, and second,
to compel only the strongest acid (which, by reason of its greater specific gravity
settles to the bottom) to flow uniformly over the same and to occupy the successive
divisions, so that at the last division only the strongest and most concentrated acid
will run off at the discharge pipe (M).
For regulating the depth of acid retained in the still I make the discharge pipe
with an arched section (N) and connect it to the still, so that it can be shifted
around to elevate or depress said section, and thus make the passage over which the
acid escapes higher or lower, as the case requires. O is the inlet pipe for the acid,
which is diagonally opposite to the outlet pipe M, thus ensuring the best results in
respect to the application of the heat to the acid in the still, and also enabling
another still to be connected thereto should occasion require.
The still is placed on a steam box (B) which is similar to the steam box A, the
same being connected by a pipe (Q) with the steam boiler, and which is also

page_text: connected with the box A by the pipe R, and under this steam box P may be a
furnace (T) for superheating the steam in it.
In using the apparatus sufficient acid is run from the leaden chamber into the
pan or box C to fill it, and to cover the bottom of the shallow pan B and the
bottom of the still (I); then the steam is let into the superheater (S) and a fire
lighted in the furnace under the box P. From the superheater S the steam is
conveyed into the box P, passing thence into the steam box A, thence through the
leaden coil of pipe G in the leaden pan or box C, and finally it discharges into the
leaden chamber H, where after being cooled in the leaden pan or box C by giving
off its heat to the acid, and thus producing a useful effect by cooling, supplies the
aqueous vapour required for generating the acid in the leaden chamber cheaper
than when made especially for that purpose, as in the ordinary method. The acid
which is first heated in the pan C passes down under the partition E, which prevents
the heavier portion from remaining in the box, and so flows on to the shallow
pan B, where it is concentrated to about sixty degrees (Beaume), and from thence it
flows into the still I, where it is concentrated to 66 degrees (Beaume).
Heretofore, the shallow pan (B) and still (I) have been placed over furnaces, and
the leaden pan being thus exposed to the fire is often overheated and melted, as the
heat required to concentrate the acid is nearly the same as is required to melt the
lead, and at best the furnace heat is irregularly distributed; whereas by the steam
heat the distribution is uniform, according to my herein-described arrangements.
By the contrivance of the dome of the still at the end where the acid enters, and
where the greater volume of vapour arises and escapes, and by contracting therefrom
towards the other end two important advantages are gained, viz., the volatile
matters are more quickly separated from the more concentrated portions, so that the
contact of the latter with the former is less as it flows along towards the escape or
discharging passage, thus facilitating the separation, and by so tapering the top a
considerable economy of material is effected, as compared with the ordinary round
conical dome-shaped still.
The equal application or distribution of the steam heat to the shallow pan B,
together with the facility of maintaining it uniformly at the highest degree of
temperature consistent with safety to the lead pan C permits a much smaller
evaporating pan to be used than when fire heat is employed.
As compared with the cost of the ordinary apparatus of the same capacity, my
apparatus can be made for about one-third of the cost of the other, while it will be
much more durable and effective.
The furnace fire may, if preferred, be used in direct contact with the still I
without the steam box P, in which case the pipe by which the steam is supplied
will be attached directly to the box A from the superheater S.
As the steam will be too hot when leaving the steam box P to be used safely
under the leaden pan B, air or steam of lower temperature may be introduced into
the first-named box (A) along with it, which will afford means for regulating the
temperature exactly as required.
In regard to the form of still as above described, and the location of the inlet
pipe and the pipe by which the vapours are conducted to the condenser, relatively
to the still so shaped and to each other, I may state that very considerable
advantages are obtained,―
First. Because, by the location of the beak or pipe leading to the condenser being
directly over the inlet, which is the place where the largest proportion of the
vapour riscs, the passage of the vapours to the beak is more direct and with less
contact with the surface of the still, so that less space is required to carry it off, and
there is less condensation by surface contact; also, what does condense and drops
back into the acid falls into what is less concentrated, and is therefore more
readily and cheaply thrown off again.
And, Second. By this location of the inlet and the beak the sloping and contracting
form of the still is permitted, because there is less vapour rising from the more

page_text: concentrated acid passing on to its outlet, which form effects a considerable economy
of the very expensive material of which the still is made.
Having now particularly described and ascertained the nature and object of the
said Invention, and in what manner the same is to be performed or carried out in
practice, I hereby declare that I claim,-
First. The utilization of the waste steam from a sulphuric acid concentrating
apparatus for supplying the aqueous vapour required in the generating chambers,
substantially as described.
Second. The combination with the leaden box C, evaporating pan B, and the
still I, of a sulphuric acid concentrating apparatus arranged in the order described;
also of the steam boxes P and A, or either of them, and the steam coil G, the same
being arranged and connected to the leaden chamber, substantially as described.
Third. The still constructed in sloping topped form with an upright beak, sub-
stantially as described.
Fourth. The use of the partition plates for strengthening and supporting the
bottom of the still, substantially as described.
Fifth. Elevating the condenser K, so that the condensed vapours from the still
flow direct into chamber H, thus dispensing with pumping, which is the method
usually employed to return the condensed vapours back to the chamber H, sub-
stantially as described.
In witness whereof, I, the said Frederick William Kalbfleisch, have here-
unto set my hand and seal, this Twenty-third day of October, in the
year of our Lord One thousand eight hundred and seventy-seven.
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