IMPROVEMENTS.IN . TREATING NITROUS ACID AND NITRIC OXIDE IN ORDER TO CONVERT THEM INTO NITRIC ACID
Year: 1862

page_text: LETTERS PATENT to George.Henry Ogston, of Mincing Lane, in the City
of London, Consulting Chemist, for the Invention of "IMPROVEMENTS.IN
. TREATING NITROUS ACID AND NITRIC OXIDE IN ORDER TO CONVERT THEM INTO
NITRIC ACID."
:
Sealed the 8th May 1863, and dated the 8th November 1862.
PROVISIONAL SPECIFICATION left by the said George Henry Ogston
at the Office of the Commissioners of Patents, with his Petition, on the
8th November 1862:
I, GEORGE HENRY OGSTON, of Mincing Lane, in the City of London, Con-
sulting Chemist, do hereby declare the nature of the said Invention for "Iм-
PROVEMENTS IN TREATING NITROUS ACID AND NITRIC OXIDE IN ORDER TO CONVERT
THEM INTO NITRIC ACID," to be as follows:-
My Invention consists in exposing these oxides of nitrogen in suitable
vessels to the action of air and water under pressure, whereby they become
converted into nitric acid. I am aware that air and water have been hereto-
fore used for a similar purpose, but owing to the absence of pressure the
result has always been more or less imperfect:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Henry Ogston in the Great Seal Patent Office on
the 8th May 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HENRY OGSTON, of Mincing Lane, in the City of London, Consulting Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of November, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said George Henry Ogston, Her special licence that I, the said George
Henry Ogston, my executors, administrators, and assigns, or such others as I,
the said George Henry Ogston, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention.for." IM-
PROVEMENTS IN TREATING NITROUS ACID AND NITRIC OXIDE IN ORDER TO CONVERT
THEM INTO NITRIC ACID," upon the condition (amongst others) that I,. the said
George Henry Ogston, my executors or administrators, by an instr
instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent..
NOW KNOW YE, that I, the said George Henry Ogston, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by. the
following statement thereof, reference being had to the Drawing hereunto
annexed, that is to say:-
The object of this Invention is to recover certain oxides of nitrogen
generated in various processes, often treated as waste products, and allowed to
escape into the atmosphere, to the great injury to the health and vegetation of
the neighbourhood in which such operations are conducted. For instance,
nitric oxide and nitrous acid occur as waste products in the manufacture of
oxalic acid by the action of nitric acid upon sugar, the operation being usually
conducted either in open vessels or in imperfectly constructed apparatus,
:

page_text: the whole of the nitric oxide génerated is thrown into the atmosphere
and lost.
Now in order to render the nitric oxide so generated available for the
reproduction of nitric acid; I effect the decomposition of the saccharine matter
in a close vessel of a construction hereafter described. In this improved
apparatus I cause the nitric oxide; together with any other oxides of nitrogen
by which it may be accompanied, to pass through a series of vessels which I
call condensers, so arranged as to subject these gases to the simultaneous
action of compressed air and water, or the vapour of water. I regulate the
pressure and temperature as may be required from time to time as the
operation proceeds.
Having referred to the object of my Invention I will now describe my
apparatus,.and the mode of using the same.
The accompanying Drawing shews the apparatus in sectional elevation.
A is a closed vessel of convenient size constructed of a material that will
résist the action of dilute nitric acid! I prefer Yorkshire slab stones free from
lime, the joints of such stones may be grooved, rabbeted, or plain put together
with suitable cement, and the whole strongly bound together with iron-bolts
and binders B, B, B, B, and C, C, C, C; DD, D, D, are wooden blocks
intervening between the sides' of the vessel to equalize the pressure over the
whole area; E, E, are earthenware funnel tubes through which the nitric acid
and sugar solution are introduced; F is a glass float to indicate the height of
the liquor standing in the generator; G is a glass thermometer, the tem-
perature being regulated either by a steam worm in the interior of the
generator, or applied externally by means of a' jacket; H, H, is an earthen-
ware tray with a' perforated bottom supported on bricks resting on the bottom
of the vessel A; I is a branch from the main air pipe J; K, a manhole door
secured with a cross bar and screw; L is an earthenware discharge cock
through which the liquor when saturated with oxalic acid is drawn off for
crystalization in the usual way. a, a, a, are earthenware pipes connecting
the generating vessel A with No. 1 nitric acid jar, which in common with the
rest of the series I call a condenser; these pipes may be put together air-tight
in any convenient way, but I prefer ground: spigot and facicet joints enveloped
in elastic bands, as represented at X, X; b, b, b, b, are branches from the pipe.
supplying compressed air with a stop-cock on each; c, c, equilibrium tube to
prevent return of the liquor'in the event of unequal pressure'in' the respective
condensers; d is a plug hole to charge the jars by; e, discharge tap; f, luted
ube to discharge excess of acid during the working. The letter, figure, and

page_text: explanation given in reference to No. 1 condenser, apply also to all the rest of:
the series.
I do not deem it necessary to detail the mechanical arrangements for
supplying compressed air further than that I prefer a double-acting air pump.
with an intermediate air vessel or reservoir, to preserve as far as possible an
uniform supply; such arrangement being well understood. And I now proceed
to detail the mode of using the apparatus above described...
I introduce a proper quantity of oxalic acid, mother liquors, (obtained from.
a previous operation) into the vessel A, and by the application of steam heat.
I bring the liquor up to the necessary temperature, and fix the manhole cover
perfectly air-tight, I then add proportionate quantities (well known to manu-,
facturers) of saccharine matter (syrup) and nitric acid through the funnel
pipes E, E, into the tray H, H, whence they pass through the perforated
bottom and diffuse freely amongst the mother liquor; there is then produced
oxalic acid with nitric oxide, and traces of carbonic acid and carbonic oxide,
the former remains in solution; the latter (the nitric oxide) being evolved in
the form of gas accumulates in the upper portion of the generator until the
pressure becomes sufficient to force these gases through whatever depth of
water it is thought desirable to introduce into the condenser. Air is now
forced into one or more of the condensers, and when this compressed air is
brought into contact with the nitric oxide, generated in the vessel A, this last,
is converted into nitrous acid; the nitrous acid thus formed is forced by the
continuous current of air through the water contained in condenser No. 2,
where the nitrous acid is resolved into nitric acid and nitric oxide, the former
remaining in solution whilst the latter passes into No. 3 condenser, where a
similar reaction takes place, each condenser diminishing very considerably the
quantity of gas to be acted upon, and the process is continued through a
sufficient number of condensers to retain the whole of the nitric oxide
originally liberated.
The number of these condensers I find it necessary to
use is from fifteen to twenty.
After the decomposition of the material in the generator A has been com-
pleted it is well to cause a strong current of air to pass into it through the
tube I, for the purpose of converting any nitrous acid that may be retained by
the liquor into nitric acid.
The pressure to be maintained in the whole series of the apparatus is
regulated by the depth to which the tube proceeding from the last condenser
is plunged under water, and this I prefer to be from 9 to 12 inches, but I do
not confine myself to this pressure.

page_text: With regard to the treatment of the oxides of nitrogen obtained otherwise
than in the production of oxalic acid, my apparatus may be used in all cases in
which these oxides can be collected and forced through the regenerating or
condensing vessels. I may especially mention the mode of dealing with the
nitrous gases that sometimes pass off from an ordinary vitriol chamber. These
gases are conducted over a large surface of oil of vitriol until this last is
moderately saturated with the nitrous acid that would otherwise escape into
the air. I then use this saturated oil of vitriol to decompose nitrate of soda
in the ordinary close cylinders. Nitric acid is first collected as usual, and the
nitric oxide and nitrous acid at the same time evolved are conducted through
my apparatus under pressure, and there converted into nitric acid, as already
described.
Having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim,-
First, converting nitrous acid and nitrous oxide into nitric acid by exposure
under pressure to air and moisture.
And, second, the apparatus herein-before described and represented in the
accompanying Drawing for effecting the conversion of nitrous acid and nitric
oxide into nitric acid.
In witness whereof, I, the said George Henry Ogston, have hereunto
set my hand and seal, this Eighth day of May, One thousand eight
hundred and sixty-three.