Year: 1886

page_text: Date of Application, 15th Feb., 1886.
Complete Left, 15th Nov., 1886.
Complete Accepted, 7th Jan., 1887.
I, HENRY JOHN LESLIE of No. 4 Coleman Street in the City of London, Chartered
Accountant do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved mode of concentrating sulphuric acid as it
proceeds from the Glover Tower or Acid Chamber, and to improved apparatus for
that purpose, whereby the waste heat from the evaporating furnace is utilised for
effecting the preliminary evaporation of water from the weak acid as it comes from
the Glover Tower or Acid Chamber, before entering the evaporating pan, while the
evaporating pan and furnace are so constructed as to be effectually protected against
injury by the acid.
For these purposes I construct, in connection with the evaporating furnace, one,
two, or more vertical chambers or towers filled with loosely piled brick or other
suitable material that is not attacked by acid, and communicating at or near the
bottom with the escape flue of the evaporating furnace, while at top it is provided
with a funnel mouthed pipe, by preference of platinum, through which the weak acid
proceeding from the Glover Tower or Acid Chamber is made to enter, so that in
flowing downward over the loose filling of the tower it is brought into intimate
contact with the hot gases from the evaporating furnace rising up from below, and
thus becomes concentrated to a certain degree by the evaporation of its watery
particles before entering the evaporating furnace, while at the same time any
sulphuric acid vapour that escapes with the furnace gases into the tower will become
condensed and pass back with the acid into the evaporating furnace. By preference
I employ two such concentrating Towers, through which the furnace gases are made
to pass consecutively so as to thoroughly utilise the heat thereof and condense the
acid vapours therein before they escape to the chimney. The said tower or towers is
or are by preference constructed of Dinas or other pure silica brick, having an outer

page_text: covering of lead protected in its inner side by asbestos sheets to which the supply
pipe for acid and the flue for the furnace gases are secured in a gas tight manner.
The evaporating furnace is constructed as follows. A lead tank is constructed of a
size corresponding to that of the furnace and is provided first with a lining of sheet
asbestos, upon which is built a thick lining of Dinas or Silica brick; upon this is
built the low arched roof of the furnace, also built of Dinas or Silica brick with an
outer covering of lead protected by asbestos. The evaporating chamber thus formed
is provided at one end with the before-mentioned escape flue for the gases, and at the
other end with a deep fire for the combustion either of a smokeless fuel such as
anthracite or coke, or of gaseous fuel from a gas producer together with the necessary
air supply. The acid proceeding from the bottom of the above described towers is led
by a pipe to a funnel mouthed pipe fixed in the roof of the furnace, near the fireplace
and the flames and hot gases pass from the fireplace over
a bridge and strike
on to the surface of the acid in the evaporating tank, heating it to boiling point, and
effecting its concentration to any required degree such as to a specific gravity of
1-845 or that of "Oil of Vitriol." The lead tank is by preference extended round
three sides of the furnace so as to form a trough for cooling the concentrated acid,
which trough is also lined, first with asbestos sheets and then with silica. bricks. The
lead parts are by preference made of a suitable alloy of lead and antimony.
By the above described construction, the leads parts are effectually protected
against being attacked by the acid, while by the improved method of operating a
considerable economy of fuel and an increased output is effected as compared with the
ordinary modes of manufacture. The apparatus is also rendered of comparatively
cheap construction, and economizes space.
ABEL & IMRAY,
28, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Apparatus for that Purpose.
I, HENRY JOHN LESLIE of No. 4 Coleman Street in the City of London,
Chartered Accountant, 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 an improved mode of concentrating sulphuric acid as it
proceeds from the Glover Tower or Acid Chamber, and to improved apparatus for
that purpose, whereby the waste heat from the evaporating furnace is utilised for
effecting the preliminary evaporation of water from the weak acid as it comes from
the Glover Tower or Acid Chamber, before entering the evaporating pan, while the
evaporating pan and furnace are so constructed as to be effectually protected against
injury by the acid.
"For these purposes I construct and arrange apparatus as I will describe referring
to the accompanying drawings. Fig. 1 is a longitudinal and Fig. 2 a transverse
section, and Fig. 3 is a sectional plan.
In connection with the evaporating furnace A, I construct one, two or more
vertical chambers or towers; in the drawing I have shewn two, B and C. These are
filled with loosely piled brick or other suitable material that is not attacked by acid.
The first tower B communicates at or near its bottom with the escape flue D of the
evaporating furnace A and at its top it communicates with the second tower C from
the bottom of which there is a flue E leading to the chimney. Through funnel
mouthed siphon pipes F, by preference made of platinum, weak acid proceeding from
the Glover Tower or Acid Chamber enters at the tops of the towers. In flowing
downward over the loose filling of the tower, the weak acid is brought into intimate
contact with the hot gases from the evaporating furnace, and thus becomes con-
centrated to a certain degree by the evaporation of its watery particles before entering
the evaporating furnace A, while at the same time sulphuric acid vapour that may
have escaped with the furnace gases into the tower becomes condensed and passes
back with the partially concentrated acid into the evaporating furnace. By preference
I employ two such concentrating towers, as I have shewn in the drawings. As the
furnace gases pass consecutively through these, their heat is thoroughly utilised and
such acid vapours as they carry with them are condensed before they escape to the
chimney. The towers are by preference constructed of Dinas or other pure silica
bricks, having an outer covering of lead, to which the supply pipes F and the furnace
flue D' are secured in a gastight manner. From the second tower Ca pipe G leads
the weak condensed acid to an evaporating furnace, at the pipe O from the first tower.
In constructing the evaporating furnace A. I employ a lead tank H provided with a
lining I of sheet asbestos, upon which is built a thick lining K of Dinas or silica
brick. Upon this is built the low arched roof L of the furnace, which is also of
Dinas or silica bricks with an outer lead covering M. At the one end of the chamber
is the escape flue D for leading the gases into the first tower B, and at the other end
is formed a deep fire place N for the combustion either of a smokeless fuel such as

page_text: anthracite or coke, or of gaseous fuel from a gas producer. The acid proceeding from
the bottom of the tower B is led by a pipe O to a funnel mouthed siphon pipe P fixed
in the roof of the chamber near the fireplace and the flames and hot gases passing
over a bridge strike on to the surface of the acid in the evaporating tank, heating it
to boiling point, and effecting its concentration to any required degree as, for
instance, to a specific gravity of 1.845 or that of "Oil of Vitriol." The lead tank is,
by preference, extended round three sides of the furnace so as to form an external
trough for cooling the concentrated acid, this trough being also lined, first with
asbestos sheets and then with silica bricks.
Although I have mentioned lead as the metal for covering the towers and lining
the chamber and tanks a suitable alloy of lead and antimony is preferred.
By the above described construction, the metallic parts are effectually protected
against being attacked by the acid, while by the method of operating set forth a con-
siderable economy of fuel and an increased output is effected as compared with the
ordinary modes of manufacture. The apparatus is also comparatively cheap in
construction, compact and durable.
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. The herein described process for concentrating sulphuric acid by causing weak
acid to pass through interstices of refractory material in towers through which hot
vapours and gases pass from an evaporating chamber, thus partially concentrating the
acid, which is farther concentrated by heat in the chamber to which it passes from the
towers, and condensing such acid as is carried by the hot gas from the evaporating.
chamber..
2. For operating according to the method above set forth, the combination of an
evaporating chamber A and of two or more towers such as B and C with their
communications, constructed and arranged substantially as described.
3. For protecting the metal from the action of hot acid, lining it with asbestos and
suitable bricks, substantially as described.