Year: 1897

page_text: Date of Application, 5th Oct., 1897
Complete Specification Left, 20th Dec., 1897-Accepted, 5th Feb., 1898
I, JEAN VILHELM SKOGLUND, residing at the City Hotel, corner of 32nd Street
and Avenue D, Bayonne City, New Jersey, United States of America, Chemist, do
hereby declare the nature of this invention to be as follows:-
In the manufacture of nitric acid, impurities pass from the still or generator
into the receiving or condensing vessel with the acid vapours, and the acid pro-
duced is more or less discoloured and contaminated by the red gases and chlorine
that are generated and requires to be purified, and this involves expense and more
or less loss of acid.
The present invention is for producing a substantially chemically pure nitric
acid at one operation and thereby saving labour, increasing the yield of acid, and
preventing loss by a second operation.
I also construct the condenser in such a manner as to render the same very
durable and less liable to become cracked or broken than the condensers heretofore
employed.
I make use of a tower or chamber of acid proof material containing pieces of
pottery, glass, or other acid proof material, and the vapours from the still are
admitted into the lower part of this tower or chamber and rise and pass between
such pieces.
The temperature of the tower is to be maintained at or near the boiling point
of the entering vapours, so that very little condensation takes place, but in con-
nection with the tower I employ a condenser in which the vapours are condensed,
and this is located above the tower so that the condensed acid, with the red gases
and impurities dissolved therein, runs back upon the pieces of acidproof material
in the chamber or tower and flows in thin films over such pieces of acidproof
material to the bottom of the tower, and in so doing, the heat of the ascending
gases and vapours acts to drive off the red gases and chlorine and other impurities,
but such heat is not sufficient to volatilize the condensed nitric acid itself, and
the same in a liquid form gradually passes to the bottom of the tower and is with-
drawn, and the operation may be further assisted by the oxidizing action of air
admitted into the tower. The result of this improvement is that chemically pure
white nitric acid is produced in one operation and without loss of acid.
In consequence of the strong nitric acid boiling at a lower temperature than the
acid diluted with water, the stronger or more concentrated acid will be the last to
condense, hence I am able to use two or more towers, or to divide one tower into
two or more sections that are maintained at successively lower temperatures, the
strongest acid passing from the last and coolest tower or section, and the weaker
acid from the first or hottest tower or section. All the acid, however, is colourless
and free from impurities. I prefer to use two towers and a condenser connected
with the outlet from the second tower.

page_text: In the condensation of nitric acid vapours, tubes of glass, pottery, or other
vitreous materials have been employed and necessarily there have been numerous
joints in such condensers that are liable to leak, and, in addition, the tubes often
become cracked or broken, involving a loss of acid, time, and materials, and these
vitreous substances usually are poor conductors and hence inefficient in transfer-
ring the heat to the condensing water.
I have discovered that the vapours passing through a condenser have very little
effect upon lead after the first condensing operation, and for this reason I make
use of a primary condenser of vitreous material for receiving the nitric acid vapours,
and connect thereto a tube of lead forming a secondary condenser and that is not
injuriously effected by such nitric acid or vapours, and hence the condenser is
permanent and very effective; and I allow condensing water to drip over a vertical
range of substantially horizontal pipes in order that the coldest water may act
upon the pipes that are nearest to the ultimate discharge of the residual vapours.
Dated this 5th day of October 1997
ERNEST DE PASS,
Chartered Patent Agent, 78, Fleet Street, London, and
A, Market Street, Nottingham, Agent for the Applicant.
Improvements CORECARD
I, JEAN VILHELM SKOGLUND, residing at the City Hotel, corner of 32nd Street
and Avenue D, Bayonne City, New Jersey, United States of America, Chemist, 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:-
_
In the manufacture of nitric acid, impurities pass from the still or generator
into the receiving or condensing vessel with the acid vapours and the acid produced
is more or less discolored and contaminated by the red gases and chlorine that are
generated and requires to be purified, and this involves expense and more or less
loss of acid.
The present invention is for producing a substantially chemically pure nitric
acid at one operation and thereby saving labor and increasing the yield of acid
and preventing loss by a second operation.
I also construct the condenser in such a manner as to render the same very
durable and less liable to become cracked or broken than the condensers heretofore
employed.
I make use of a tower or chamber of acid proof material containing pieces of
pottery, glass or other acid proof material, and the vapors from the still are
admitted into the lower part of this tower or chamber and rise and pass between
such pieces.
The temperature of the tower is to be maintained at or near the boiling point of
the entering vapors, so that very little condensation takes place, but in connection
with the tower I employ a condenser in which the vapors are condensed and this
is located above the tower so that the condensed acid, with the red gases and
impurities dissolved therein, runs back upon the pieces of acid proof material in
the chamber or tower and flows in thin films over such pieces of acid proof material
to the bottom of the tower, and in so doing the heat of the ascending gases and
vapors acts to drive off the red gases and chlorine and other impurities, but such
heat is not sufficient to volatilize the condensed nitric acid itself, and the same in

page_text: a liquid form gradually passes to the bottom of the tower and is withdrawn, and
the operation may be further assisted by the oxidizing action of air admitted into
the tower. The result of this improvement is that chemically pure white nitric
acid is produced in one operation and without loss of acid.
In consequence of the strong nitric acid boiling at a lower temperature than the
acid diluted with water, the stronger or more concentrated acid will be the last to
condense, hence I am able to use two or more towers or to divide one tower into two
or more sections that are maintained at successively lower temperatures, the
strongest acid passing from the last and coolest tower or section, and the weaker
acid from the first or hottest tower or section. All the acid, however, is colorless
and free from impurities. I prefer to use two towers and a condenser connected
with the outlet from the second tower.
In the condensation of nitric acid vapors, tubes of glass, pottery or other vitreous
materials have been employed and necessarily there have been numerous joints
in such condensers that are liable to leak, and in addition the tubes often become
cracked or broken, involving a loss of acid, time and materials, and these vitreous
substances usually are poor conductors and hence inefficient in transferring the
heat to the condensing water.
I have discovered that the vapors passing through a condenser have very little
effect upon lead after the first condensing operation, and for this reason I make
use of a primary condenser of vitreous material for receiving the nitric acid vapors
and connect thereto a tube of lead forming a secondary condenser and that is not
injuriously effected by such nitric acid or vapors, and hence the condenser is
permanent and very effective; and I allow condensing water to drip over a vertical
range of substantially horizontal pipes in order that the coldest water may act
upon the pipes that are nearest to the ultimate discharge of the residual vapors.
In the drawing, I have represented by a diagrammatic sectional elevation the
present improvement and have shown two vertical towers A and A. If the two
towers are made use of, the nitric acid vapors from the ordinary generator will
be conveyed into the vessel A¹ by the supply pipe C, but if only one tower A is
employed, the acid vapors from the generator will be conveyed into the same by a
supply pipe as indicated by dotted lines at C¹.
A pipe at D is provided in the tower through which air may be forced in the
proper quantities, and the tower is closed at the top and contains pieces of acid
proof material resting upon a perforated bottom F that is supported by standards d,
all of acid proof materials, and the entire tower rests upon a pier or other support B.
The acid proof materials within the tower or towers may be porcelain, pottery,
quartz, glass or similar material in any sizes or shapes of pieces so as to loosely
fill the tower and allow the acid vapors from the pipe C to ascend and the liquid
in a thin film, to run gradually down the tower. These acid proof materials are
represented at e.
Where the two towers are used as shown, the pipe H passes from the top of one
tower to the bottom of the next tower, and the second tower is substantially similar
to the first both in its construction and operation.
A condenser of any suitable character is employed for receiving the vapors
that pass from the top of the tower: I prefer and use the condenser represented
in which the pipe N is of glass, pottery, or similar material and receives the vapors
from the top of the tower A, and its upper end is connected to the lower end of the
metal pipe N1, and this pipe N¹ is led backwards and forwards and forms a vertical
range of substantially horizontal pipes, and these are suitably supported, as shown
at R, and a pipe or trough P is used for supplying water and the same runs through
perforations and trickles over the pipes from the upper to the lower pipe, and such
water is received in a pan and allowed to run off by the pipe O, and the upper end
of the pipe N¹ passes into a vessel S, which is preferably of porcelain, or similar
material, and is, kept at a low temperature so as to condense any useful vapors or
gases that may escape from the condenser, and the pipe T leads any gases or uncon-
densed vapors to any suitable place of discharge, or to a condenser for any lower

page_text: oxides of nitrogen, chlorine, or other vapors, and there is a pipe L' leading from
the bottom of the vessel S to the top of the column A, and pipes may also be pro-
vided through which nitric acid may be allowed to flow at any desired temperature
and in any desired quantities, so as to pass in thin films over the acid proof
materials in the tower or towers, and in this manner the temperature of such
towers for the aforesaid operations may be regulated.
It is advantageous to employ a deflector G upon which the acid from the con-
denser runs into the tower and is spread upon the acid proof materials in such
tower so as to pass down in thin films as the vapors ascend, and the nitric acid, in
a substantially chemically pure condition, can be drawn off from the bottom of
the tower by the pipe E which is advantageously made with a trap a to prevent
the escape of vapors, and from the bottom of the tower A a weaker acid will be
drawn than that which is taken from the bottom of the tower A, all as before
described.
As before indicated, the primary portion N of the condenser that first receives
the acid vapors from the tower is of vitreous material, and a condensation takes
place in the same of those liquids or vapors that would attack a pipe of pure lead,
and the vapors passing into the secondary portion of the condenser do not
injuriously affect the lead, and hence but one joint is necessary between the leadi
and the vitreous material as at 2, and it is advantageous to apply a band at 3 around
the pipe N and near the joint 2 to prevent the condensing water ruuning upon
the joint.
The ordinary lead of commerce is more or less easily attacked by nitric acid
especially when in a hot condition and of 43 to 45° Beaume in strength, but sub-
stantially chemically pure lead will resist boiling strong nitric acid containing
less than ten per cent. of water.
The acid as it runs away by the pipes E may be cooled in any desired manner,
and the acid that is not sufficiently concentrated may be redistilled.
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 :-
First: The method herein specified of manufacturing nitric acid, consisting
in conveying the nitric acid vapors into a chamber containing pieces of acid proof
material, causing such vapors to condense and run in thin films over such pieces
of acid proof material and maintaining the temperature of such chamber at the
temperature of the incoming nitric acid vapors or nearly so for driving off
impurities from the acid, substantially as set forth.
Second: The method herein specified of manufacturing nitric acid, consisting
in passing the nitric acid vapors into a chamber containing pieces of acid proof
material, maintaining the temperature of said chamber equal to or higher than
the boiling point of the nitric acid, allowing the weak acid to condense and ruu
off, passing the remaining nitric acid vapors into a second tower or chamber con-
taining pieces of acid proof material and maintaining such tower or chamber at a
temperature corresponding or nearly so to the entering nitric acid vapors, con-
densing the vapors and allowing the nitric acid to run back over the pieces of acid
proof material in the form of thin films and conveying away the gaseous
impurities thereby producing a substantially pure nitric acid, substantially as
set forth.
Third: The method herein specified of making nitric acid, consisting in passing
the nitric acid vapors into a chamber or tower containing pieces of acid proof
material, condensing such vapors and allowing the nitric acid to run in thin films
over the pieces of acid proof material, maintaining the temperature sufficiently
high to drive off impurities and simultaneously exposing the acid to the oxidizing
action of atmospheric air, substantially as specified.
Fourth In the manufacture of concentrated nitric acid, a primary condenser

page_text: of acid proof material, and a secondary condenser connected therewith of lead,
substantially as set forth.
Dated this 20th day of December 1897.
ERNEST DE PASS,
Chartered Patent Agent, 78, Fleet Street, London, and
5A, Market Street, Nottingham, Agent for the Applicant.