Improvements in Apparatus for the Concentration of Sulphuric Acid and other Liquids by Evaporation.
Year: 1898

page_text: Improvements in Apparatus for the Concentration of Sulphuric
Acid and other Liquids by Evaporation.
I, OSCAR GUTTMAN, of 12, Mark Lane, in the City of London, Consulting Engineer
and Chemical Adviser, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in apparatus for the concentration by
evaporation of sulphuric acid, and other mineral acids and liquids, which are capable
of being concentrated by means of heat applied to the exterior of the vessels, in
which the acid or other liquid is contained and to the surface of the liquid under-
going evaporation.
The concentration of such liquids has hitherto been frequently effected by the
well known method of arranging a series of open evaporating vessels of glass, porce-
lain, or similar material in a row, such vessels being placed in steps so that the
upper part of one vessel in the series is slightly above that of the next vessel in
the series. The liquid undergoing evaporation is run into the upper vessel of the
series and conducted therefrom by a spout into the next lower vessel of the series
through a pipe or funnel dipping some distance below the level of the liquid in the
lower vessel, thus causing the less concentrated liquid coming from the upper vessel
to rise through the more concentrated liquid in the lower vessel, and so on through
the series of vessels. The stepped series of evaporating vessels above mentioned
are set in a long rectangular structure, in which the vessels are exposed to
heated. gases of combustion from a fire or furnace, whilst the upper surface of the
liquid in the vessels communicates with the upper part of the rectangular structure,
which sometimes forms an outlet flue for conveying away the acid aqueous vapour
produced during evaporation. In this way the weaker acid or liquid fed into the
upper vessel of the series of evaporating vessels is gradually concentrated in its
passage from one vessel of the series to the other in the manner described, so that
concentrated acid is delivered from the lowest, vessel of such series.
In some
forms of the apparatus above described the whole of the exterior surface of the
vessels, together with the upper surface of the liquid in such vessels, are kept in
contact with the heated gases of combustion so as to materially assist the concen-
tration by the surface evaporation of the exposed liquid, and in some cases the
evaporating vessels are placed or carried in sand baths placed within the rectangular
structure in a manner well known and understood.
The evaporating apparatus above described, however, has certain material dis-.
advantages, which it is the object of this my invention to obviate. Amongst these
I may mention, that such form of apparatus is expensive to construct and maintain,
and it occupies a considerable space. Access to the evaporating vessels in case of

page_text: fracture, an occurrence by no means uncommon, is difficult, and when such fracture.
occurs, the replacement of the fractured vessel is difficult and inconvenient and
occupies a considerable time, during which the whole process of concentration must
be stopped, thereby occasioning great loss of time. Besides this there is no means
of quickly and readily locating the position of the fractured vessel, which involves
both a loss of acid and time, and by reason of the large body of fumes given off
renders the subsequent replacement of the broken vessel more difficult and
inconvenient.
My improvements consist in arranging a series of glass, porcelain, or other
evaporating vessels, one above the other inside a vertical tower of circular, square, or
other convenient section, such tower being made of iron or other refractory material,
each vessel resting on a horizontal tray or shelf, and the whole so placed as to form a
spiral, the axis of which coincides with that of the tower. Each of the trays, which
carry or support the vessels, projects into the interior of the tower and is fixed to a
part of the shell of the tower and each of such portions of the shell
of the tower is carried by a hinge or swivel formed on a fixed portion
of the tower, thus constituting a moveable or swivelling door, so that by opening
such swivelling door the evaporating vessel, which is carried upon the tray fixed
thereto can be at once examined or withdrawn from the tower. It is obvious, that
such a mode of construction admits of a large number of evaporating vessels being
arranged spirally one above the other, to deliver the acid or liquid undergoing
evaporation from one to the other, in a small space and that the larger the tower is
in cross section, the greater the number of evaporating vessels, which can be placed
inside it. The top of the tower may be closed by a slab of stone or other refractory
material and may carry a tank or other vessel, from which the dilute acid may be fed
to the first of the series of the evaporating vessels inside the tower, and thus the acid
or liquid in passing from one evaporating vessel to the other will traverse a path of
considerable length. The trays, which carry the evaporating vessels, may be arranged
to communicate by means of a hole, tube, or small opening leading to the exterior of
the tower and terminating in a vertical channel formed on a fixed portion of the
exterior of the tower, so that leakage from any broken or cracked vessel may at once
become apparent and be easily and quickly located. The top of the tower must be
provided with an outlet pipe or flue so as to convey the heated gases of combustion
employed for the purpose of evaporation, together with the aqueous products of
evaporation, to a suitable condenser or other receptacle or into the open air. The
lower part of the tower is secured to a suitable foundation and provided with
appropriate means and apparatus for the admission and control of the heated gases
used in the tower to effect the evaporation, and the source of heat furnishing such
gases may be an ordinary coke or coal fire, the products of combustion from which
are conveyed through the tower; but I prefer to use producer or water gas, which
will give a less carbonaceous deposit, in the manner, which is well known and
understood in heating or evaporating substances.
A suitable form of apparatus for carrying my invention into effect may consist of
three or more cast iron vertical pillars or columns of suitable section, securely fixed to
a base below and held in place at the top by a cast iron ring or stay pieces, the whole
resting on a brick, stone, or iron foundation. To the pillars hinges are fixed, which
carry cast iron swivelling doors having fixed to or cast in one with them horizontal
cast iron trays each provided with a raised external rim and a slightly conical lower
surface. These trays carry, standing freely thereon or in an iron pot with or without
a layer of sand, the glass or porcelain evaporating vessels, and the doors and trays are
so arranged and placed, that, when they are securely closed and fastened by suitable
means, a tower, as above mentioned and described, is formed with the evaporating
vessels one above the other and arranged spirally so as to be capable of delivering the
acid or liquid under treatment from the top of the tower to the bottom from vessel to
vessel in succession. Each of the evaporating vessels is provided with a spout
delivering the liquid overflowing therefrom into a flat shaped funnel resting on the
.vessel next below, and a pipe from such flat shaped funnel conveys the liquid to the

page_text: lower part of the vessel upon which it rests. On the side of each of the cast iron trays
carrying the evaporating vessels I provide a conical projection, which fits into a
corresponding recess in the pillar against which the door, to which the tray is fixed,
abuts, when it is closed, and a hole or perforation from within the rim of the tray
communicates with a corresponding hole or pipe in such pillar terminating in a recess
or groove formed vertically along the outer part of the pillar, so that any liquid
escaping from the evaporating vessel thereon is at once led away to the outside of the
tower and may be at once detected. By this means a fractured or overflowing vessel
may be readily located, and the conical under surface of the tray before mentioned
serves to carry away any moisture, which may condense thereon. When the
evaporating vessels are placed in iron pots on the trays, with or without sand, such
pots are provided with a small hole, so as to allow the acid escaping from the
fractured evaporating vessel to run out on to the tray and be carried to the exterior '
of the tower as before described. Each of the doors of the tower abuts the one
against the other and against the pillars by means of angular surfaces, so as to
prevent the escape of fumes, and if requisite, the joints of the doors may be
luted in the usual manner, so as to more effectually prevent the escape of acid fumes.
The interior of the doors forming the tower in the manner described may be covered
or lined with fire bricks, asbestos, or other acid resisting materials, but I do not find
this to be absolutely requisite, when concentrating sulphuric acid, because, as is well
known, the surface of the cast iron tower will be little affected by the acid fumes.
The exterior of the doors forming the tower, as well as the other exposed parts
thereof, may with advantage be covered with some non-conducting material, e.g.
kieselguhr, so as to minimise radiation and consequent loss of heat.
The top of the tower I close by means of a flagstone or plate of fireproof material
resting on the upper ring or stays before mentioned, and on this stone or plate I
fix a tank, in which I place a number of vessels made of lead similar in all respects
to the glass or porcelain evaporating vessels and communicating with each other in a
similar way, so that the incoming dilute acid or liquid is preheated by the gases
before they issue through an outlet pipe in the upper part of the tower. The tank is
closed by means of a cover and a fume pipe leads to the outside; the liquid from the
last of the leaden vessels in the tank is delivered into the first of the series of
evaporating vessels inside the tower, either by means of a pipe passing through the
stone cover or it is conveyed out through the tank and into the first evaporating
vessel by means of a pipe passing through the upper ring of the tower, to which the
upper part of the columns of the tower are fixed as before described.
I provide the lower part of the tower with suitable openings and valves for the
admission and control of the heated gases of combustion as before described or for
the mixture of gas and air, when I employ producer or water gas, and I distribute the
heated or incandescent gas by means of a distributing iron ring provided with suit-
able nozzles, or through perforated bricks in the manner usually employed in
distributing such gases in furnaces.
The concentrated acid or liquid from the lowest evaporating vessel within the tower
discharged through an opening in the door carrying such vessel upon the tray
fixed thereto or through an opening in the pillar, against which the door abuts, into
a cooler of suitable construction.
Such an evaporating apparatus as above described can contain for example sixteen
glass or porcelain evaporating vessels and seven preheating lead vessels without
occupying more space than that occupied by a column of three and a half feet in
diameter and a height of fifteen feet including the height for the cooler, thus occupy-
ing about one tenth of the space required for a concentrating apparatus of the same
capacity when constructed in the manner heretofore employed. It is also manifest,
that every part of the apparatus can be easily examined, any fractured evaporating
vessel can be quickly withdrawn, exchanged and replaced without such vessel being
required to be of any special shape, and without disturbing any other evaporating
vessel. The construction of the evaporating tower described is also such that the

page_text: whole can expand and contract without its stability being impaired, so that the cost
of maintenance is reduced to a minimum.
DL11"
21
1
2000
Improvements in Apparatus for the Concentration of Sulphuric
Acid and other Liquids by Evaporation.
I, OSCAR GUTTMANN, of 12, Mark Lane, in the City of London, Consulting Engineer
and Chemical Adviser, 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 :—
My invention relates to improvements in apparatus for the concentration, by
evaporation, of sulphuric acid, and other mineral acids and liquids, which are capable
of being concentrated by means of heat applied to the exterior of the vessels in which
the acid or other liquid is contained, and to the surface of the liquid undergoing
evaporation.
The
The concentration of such liquids has hitherto been frequently effected by the well
known method of arranging a series of open evaporating vessels of glass, porcelain,
or similar material, in a row, such vessels being placed in steps so that the upper part
of one vessel in the series is slightly above that of the next vessel in the series.
liquid undergoing evaporation is run into the upper vessel of the series and conducted
therefrom by a spout into the next lower vessel of the series, through a pipe or funnel
dipping some distance below the level of the liquid in the lower vessel, thus causing
the less concentrated liquid coming from the upper vessel to rise through the more
concentrated liquid in the lower vessel, and so on through the series of vessels.
Sometimes these vessels have a flat or semicircular vertical partition, which reaches
nearly to the bottom of the vessel, and the liquid undergoing evaporation runs direct
from one compartment of the upper vessel into the other compartment of the lower
vessel by means of a spout without the interposition of a funnel or pipe. The stepped
series of evaporating vessels above mentioned are set in a long rectangular structure,
in which the vessels are exposed to the heated gases of combustion from a fire or
furnace, or the combustion of producer or water gas, whilst the upper surface of the
liquid in the vessels communicates with the upper part of the rectangular structure,
which sometimes forms an outlet flue for conveying away the acid aqueous vapour
produced during evaporation. In this way the weaker acid or liquid fed into the
upper vessel of the series of evaporating vessels is gradually concentrated, in its
passage from one vessel of the series to the other, in the manner described, so that
concentrated acid is delivered from the lowest vessel of such series. In some forms of
the apparatus above described the whole of the exterior surfaces of the vessels, together
with the upper surfaces of the liquid in such vessels, are kept in contact with the
gases of combustion, so as to materially assist the concentration by the surface
evaporation of the exposed liquid, and in some cases the evaporating vessels are
placed or carried in sand baths, placed within the rectangular structure, in a
manner well known and understood.
My improvements consist, in arranging a series of glass, porcelain, or other
evaporating vessels, one above the other, inside a vertical tower of circular, square, or

page_text: other convenient section, such tower being made of iron or other refractory material,
each vessel resting on a horizontal tray or shelf, the series of vessels being so placed
as to form a spiral the axis of which coincides with that of the tower. Each of the
trays, which carry or support the vessels, projects into the interior of the tower, and
each of such parts of the shell of the tower is carried by a hinge or swivel formed on
a fixed portion of the tower, thus constituting a moveable or swivelling door, so that
by opening such swivelling door the evaporating vessel, which is carried upon the
tray fixed thereto, can be at once withdrawn from the tower. It is obvious, that such
a construction admits of a large number of evaporating vessels being arranged
spirally one above the other, to deliver the acid or liquid undergoing evaporation
from one to the other, in a small space, and that the larger the tower is in cross
section the greater the number of evaporating vessels which can be placed inside it.
The top of the tower may be closed by a slab of stone, or other refractory material,
and may carry a tank or other vessel from which the dilute acid may be fed to the
first of the series of the evaporating vessels inside the tower, and thus the acid or
liquid, in passing from one evaporating vessel to the other, will traverse a path of
considerable length. The trays which carry the evaporating vessels may be arranged
to communicate by means of a hole, tube, or small opening with a vertical channel
formed on a fixed portion of the exterior of the tower, so that leakage from any
broken or cracked vessel may at once become apparent, and so be easily and quickly
located. The top of the tower must be provided with an outlet pipe or flue, so as
to convey the heated gases of combustion employed for the purpose of evaporation,
together with the aqueous products of evaporation, to a suitable condenser or other
receptacle, or into the open air. The lower part of the tower is secured to a suitable
foundation, and provided with appropriate means and apparatus for the admission
and control of the heated gases used to effect the evaporation. The source of heat,
furnishing such gases, may be an ordinary coke or coal fire, the products of com-
bustion from which are conveyed through the tower; but I prefer to use producer
or water gas, the combustion of which will give a less carbonaceous, deposit, in the
manner which is well known and understood, in. heating or evaporating.
For the reasons before mentioned the air required for the combustion of the
producer of water gas, when such is employed, may with .advantage undergo a
preliminary heating by the waste heat from the apparatus itself. This can be
accomplished by leaving an air space between the plate on the top of the tower and
the tank for the dilute acid before described, which air space communicates with the
outer air through suitable openings, and also with the columns forming the tower,
which for this purpose are cast hollow. The columns are connected with channels
formed in the foundation of the tower, and communicate with a circular or annular
channel or flue, formed either by a suitable iron casting, or by brickwork, or partly by
iron and partly by brickwork. Through the inner wall of the annular flue the gases
of combustion are carried into the apparatus, so that, when the said inner wall
becomes heated by the burning gases the air circulating round the annular flue is
heated by contact therewith. The heated air issues from such. annular flue, through
a channel and pipe, and is conveyed away under the grate or burner. If required,
cold air can be brought direct to the annular heating flue by means of a damper.
A suitable form of apparatus for carrying my invention into effect is shown on the
accompanying drawing, wherein :-
Fig. 1, represents an outside view of the tower.
Fig. 2, a longitudinal section thereof on line A B.
Fig. 3, a plan of the top tank for the dilute acid.
Fig. 4, a horizontal section of the tower.
Fig. 5, a vertical section through the concentrated acid outlet.
Figs. 6 and 7, a plan and section respectively of an alternative system of vessels.
The apparatus consists of two cast iron vertical carrying pillars or columns a, and a
and two cast iron fixing pillars or columns a, and a., both of suitable section, securely
fixed below to a cast iron ring b and held in place at the top by a cast iron ring c,

page_text: the whole resting on a brick, stone, or iron foundation d. To the carrying pillars
hinges e are fixed, which carry cast iron swivelling doors f, having fixed to, or cast in
one with them, horizontal cast iron trays g, each provided with a raised external
rim h, and a slightly conical or inclined lower surface. These trays carry, standing
freely thereon or in an iron pot with or without a layer of sand j, the glass or
porcelain evaporating vessels ; and the doors and trays, together with some smaller
doors fa without trays made to fill up.vacant spaces, are so arranged and placed, that
when they are securely closed and fastened by catches m, a tower, as above men-
tioned and described, is formed, with the evaporating vessels one above the other,
and arranged spirally, so as to be capable of delivering the acid, or liquid under
treatment, from the top of the tower to the bottom, from vessel to vessel in succes-
sion. Each of the evaporating vessels is provided with a spout n, delivering the
liquid overflowing therefrom into a flat shaped funnel o₁, resting on the vessel next
below, and a pipe 02 from such flat shaped funnel conveys the liquid to the lower
part of the vessel upon which it rests, whilst lugs os keep the funnel in its place. If
the vessel has a dividing partition as in Fig. 6 and 7, then the liquid flows into the
compartment o₁, passes through the compartment os and runs over through the
spout n without the use of the funnel and pipe above mentioned. Each of the cast
iron trays carrying the evaporating vessels is provided with openings g., for the better
distribution of the gases ascending the tower, and is also provided with a conical
projection gs, which fits into a corresponding recess g, in the pillar to which the door
carrying the tray is hinged, and a hole or perforation, from within the rim of the tray,
passes through g, and, continuing through g₁, communicates with a hole or pipe in
such pillar terminating in a recess or groove gs, formed vertically along the outer
part of the pillar; so that liquid escaping from any of the evaporating vessels is
quickly led away to the outside of the tower and at once detected. By the means
above described a fractured or overflowing vessel may be readily located; and the
conical or inclined under surface of the tray, before mentioned, serves to carry away
any moisture which may condense thereon. When the evaporating vessels are placed
in iron pots on the trays, with or without sand, such pots are provided with a small
hole e, so as to allow the acid escaping from the fractured evaporating vessel to run
out gradually on to the tray, and to be carried to the exterior of the tower as before
described. Each of the doors of the tower abuts the one against the other, and
against the pillars, by means of angular surfaces p, so as to prevent the escape of
fumes, and the horizontal joints of the doors may be luted, in the usual manner,
so as to more effectually prevent the escape of acid fumes, and this may be also further
promoted by an exhaustor or chimney shaft, placed at the end of the outlet pipe which
carries off the fumes, in any well known manner. The interior of the doors, forming
the tower in the manner described, may be enamelled, or covered, or lined, with fire
bricks, asbestos, or other acid resisting materials, or painted with acid proof paint. The
exterior of the doors forming the tower, as well as such other exposed parts thereof,
may, with advantage, be covered with some non-conducting material, e.g. kieselguhr,
so as to minimise radiation and consequent loss of heat.
The top ring c has a plate q cast therewith, and carries a cast iron tank 7, in which
either a number of lead or porcelain vessels connected in the usual way are placed, or
in which a lead tank s stands, such tank having a number of radial partitions s
issuing from a central ring 8. Each of the divisions so formed are connected alter-
nately at the top and bottom by means of holes or opening 8, so as to cause the liquid,
entering the first of such divisions from the central ring, to run in a zigzag line and
up and down through the whole of the divisions successively. The acid enters the
centre of this tank through a funnel t, and, in its circuitous path through the leaden
tank, is preheated by the hot gases of the apparatus, before they issue through the
outlet pipe u in the upper part of the tower. The tank is closed by means of a cover v₁,
and a fume pipe v₂ leads to the outside. The liquid from the last compartment, or
lead vessel in the tank, is either delivered into the first of the series of evaporating
vessels inside the tower, by means of a pipe passing through the cover plate q, or it is

page_text: conveyed from the tank by means of a funnel pipe w₁ into the first evaporating
vessel by means of an inlet funnel w₁.
If the products of combustion of a coal or coke furnace are used for heating the
apparatus, they are introduced directly into the lower ring of the tower; but if pro-
ducer or water gas is used, it is admitted through a valve ₁, and at the same time
air is admitted through a valve, and the two enter the mixing chamber Y1, whence
the mixture is brought through two perforated plates y, and y, of iron, stone or
other suitable material and through a finely perforated burner plate y₁, where the com-
bustible mixture is lighted and consumed. The holes in the plates_y₂ and Ys do not
face each other, so as to obtain better mixing of the air and gas.
In order to make
the combustion more effective, and to prevent the cold air injuring the concentra-
ting vessels, the top ring c is made high enough to allow a space q₂ to be formed
between the plate 9 and the tank r. This space communicates with the outer air
through slots or holes c₂ and by means of openings c, it also communicates with the
hollow space down the centre of each of the pillars of the tower and with the bottom
ring 6 through corresponding openings b₂, which lead to channels b, formed in the
brickwork. The burner plate y₁ is carried by a circular conical casting 35, which is
made hollow or so shaped, that, when the brickwork of the foundation is built up to
it, a channel or annular flue b₁ is formed with which the small flues by coming from the
columns communicate. It is obvious, that the air coming in at the top of the tower
is preheated by passing over the top plate q and through the pillars, and is finally
strongly heated by means of the heat radiating from the gas burner through the
annular flue or passage b. Should it be found necessary to admit air direct to the
interior of the tower, this can be readily effected through a damper bg, which commu-
nicates by means of another small flue with the annular flue b. From the flue b₁ a
channel fitted with an iron pipe be conveys the heated air through the valve x2 and
through the pipe 3 into the mixing chamber y₁.
The concentrated acid or liquid from the lowest evaporating vessel within the
tower is discharged, through an hydraulically closed opening in the door
carrying such vessel upon the tray fixed thereto, into a cooler of suitable con-
struction, and in such opening, the thermometer and hydrometer z requisite
to observe the temperature and strength of the concentrated acid or liquid may be
placed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
(1). A tower or vertical furnace for the concentration of liquids by evaporation,
consisting of, fixed columns provided with hinged or swivelling doors forming the body
of the said tower by abutting against each other and against other fixed columns, the
said doors carrying a series of evaporating vessels arranged in steps, spirally, so that
the liquid undergoing evaporation shall be delivered from one vessel to another, from
the top to the bottom of such tower, and exposed to a current of heated gas circula-
ting throughout the said tower.
(2). In an evaporating tower or furnace the means of detecting leakage from the
evaporating vessels used therein, consisting of a fixed or swivelling plate carrying an
evaporating vessel with or without a sand bath, such plate being provided with a
raised rim and communicating by means of a pipe, tube, or its equivalent, with the
exterior of the tower or furnace.
(3). In an evaporating tower or furnace, heated by gaseous fuel, an annular
heating chamber or flue formed around the burner of the furnace for the
purpose of highly heating the air admitted to the interior of the said tower or
furnace.
(4). In an evaporating tower or furnace, the means for preheating the air admitted
into the interior thereof, consisting of a chamber, through which the cold air passes
on its way to the interior of the furnace, heated by the waste gases leaving the said
tower or furnace, in combination with passages formed in the body or shell of the

page_text: tower or furnace, and heated therefrom, and communicating with the air inlet into
the interior of such tower or furnace.
(5). The tower or furnace, for the concentration by evaporation of sulphuric acid
and other liquids, substantially as described and shown.
Dated this Fifth day of December 1898.
OSCAR GUTTMANN.