IMPROVEMENTS IN APPARATUS FOR SEPARATING AMMONIA FROM BLAST FURNACE AND OTHER GASES OR VAPORS
Year: 1881

page_text: LETTERS PATENT to Gavin Chapman of Glasgow in the County of Lanark
North Britain Manufacturing Chemist for an Invention of IMPROVEMENTS
IN APPARATUS FOR SEPARATING AMMONIA FROM BLAST FURNACE AND
OTHER GASES OR VAPORS.
PROVISIONAL SPECIFICATION left by the said Gavin Chapman at the Office
of the Commissioners of Patents on the 17th December 1881.
GAVIN CHAPMAN, of Glasgow, in the County of Lanark, North Britain,
Manufacturing Chemist. "IMPROVEMENTS IN APPARATUS FOR SEPARATING
AMMONIA FROM BLAST-FURNACE AND OTHER GASES AND VAPORS."
This Invention has for its object to utilise the ammonia existing in blast-
furnace and other gases or vapors, by separating it by means of simple and
convenient apparatus.
In carrying out the Invention the gases or vapors to be operated on are caused
to pass through a vessel or chamber having in it a number of diaphragms, disks,
or screens which are kept constantly wetted with a solution of sulphuric or other
suitable acid. The diaphragms, disks, or screens, are formed with perforations or
openings and are placed across the vessel or chamber so that the gases or vapors
must pass through such perforations or openings; and the perforations or openings
of one of the diaphragms, disks, or screens, are by preference placed so as to face
the unperforated parts of the diaphragms, disks, or screens next to them.
In one simple and convenient modification circular disks fixed on a longitudinal
shaft are employed and the lower part of the vessel is filled with the acid solution
whilst the gases or vapors pass along the upper part through the perforations in
the disks. The shaft is made to rotate at a suitable rate so that all parts of the
disks become repeatedly wetted. Water is continually added to make up for the
evaporation caused by the heat of the gases or vapors, and acid is also added in

page_text: proportion as it combines with the ammonia. The sulphate or other salt of
ammonia formed is withdrawn in any convenient way when crystallised.
In another modification the diaphragms, disks, or screens, are arranged to be
continually dipping vertically into and rising out of the acid solution; and in a
third modification the diaphragms disks, or, screens are stationary and the acid
solution is continually pumped up and distributed over their upper ends so as to
run down and keep their surfaces constantly wet.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Gavin Chapman in the Great Seal Patent Office on the 10th
June 1882.
GAVIN CHAPMAN, of Glasgow, in the County of Lanark, North Britain,
Manufacturing Chemist "IMPROVEMENTS IN APPARATUS FOR SEPARATING
AMMONIA FROM BLAST-FURNACE AND OTHER GASES OR VAPORS"
My said Invention has for its object to utilise the ammonia existing in blast-
furnace and other gases or vapors, by separating it by means of simple and
convenient apparatus
In carrying out my Invention the gases or vapors to be operated on are caused
to pass through one or more vessels or chambers, each having in it a number of
diaphragms, disks, or screens which are kept constantly wetted with a solution of
sulphuric or other suitable acid. The diaphragms, disks, or screens are formed
with perforations or openings and are placed across the vessel or chamber so that
the gases or vapors must pass through such perforations or openings; and the
perforations or openings of one of the diaphragms, disks, or screens, are by
preference place so as to face the unperforated parts of the diaphragins, disks,
or screens next to them.
The precise details and arrangement of my improved apparatus may be modified
in various ways; but in order that my Invention and the manner of performing
the same may be properly understood I hereunto append a Sheet of explanatory
Drawings to be hereinafter referred to and representing by way of example one
Bimple and convenien tmodification
Figures 1 and 2 on the accompanying Sheet of Drawings are respectively a
transverse vertical section and a longitudinal vertical section of a vessel fitted
with apparatus for carrying out my Invention. In these Drawings the same
reference numerals are used to mark the same or like parts wherever they are
repeated.
In the modification shown in Figures 1 and 2 a number of circular disks, 3,
fixed on a longitudinal shaft, 4, are employed, being placed in a vessel 5, 6, 7, the
upper part 5, of which is of a semicylindrical form very slightly larger, internally,
than the edges of the disks, 3. The lower part, 6, 7, of the vessel may be of a

page_text: rectangular or other convenient form, being represented as having one side, 6;
vertical and continuous with the cover, 5, whilst the other side, 7, is inclined and
is open at the top for convenience in filling in and examining the acid solution.
Within the inclined side, 7, there is an inner side piece, 8, which is a continuation
of the cover, 5, and dips down beneath the level of the acid solution and prevents
the escape of gas at the lateral opening, 9. The gas enters by a pipe, 10, at one
end of the vessel and passes off by a pipe, 11, at the other end; and in the vessel
it occupies the upper part, the lower part of the vessel being filled with the neid
solution. The disks, 3, are made with perforations or holes through which the gas
has to pass in proceeding from one end of the vessel to the other, a small portion
getting between the edges of the disks, 3, and the cover, 5. The shaft, 4, is made
to rotate at a suitable rate, that of about ten revolutions per minute being found
to answer in practice, and the rotation causes the disks to be moved round through
the acid solution so as to be freshly wetted with it repeatedly. A convenient rate
of flow for the gases along the pipes, 10, 11, is that of about 500 feet per minute;
and the gases flowing at this or other suitable velocity repeatedly impinge upon
the wetted surfaces of the disks, 3, in consequence of which the acid in the solution
takes up the ammonia in the gases and separates it from them.
The disks, 3, may be made of wood or other material not inconveniently acted
on by the acid. The shaft, 4, may be of iron protected from the action of the acid
by a coating of lead, or vulcanised rubber or other suitable material. The disks, 3,
may be simply strung upon the shaft, 4, and can be sufficiently secured by means
of screw nuts, 12, at the ends. The vessel, 5, 6, 7, 8, 'may be constructed of wood
but is by preference lined with lead; it is provided with a discharge cock, 13, for
drawing off the liquid.
I prefer to use two three or more of the vessels arranged in series so that the
gases may pass through them in succession; and the apparatus may be worked in
different ways. According to one plan fresh acid solution is put into, say, the
third vessel of the series through which the gases pass after it has passed through
the other two and has had a large part of its ammonia abstracted. The solution
is passed from the third to the second vessel in which whilst it has less free acid
there is a larger proportion of ammonia in the gases; and it is afterwards passed
into the first vessel in which whilst it has still less free acid the gases have their
full proportion of ammonia. From the fir-t vessel the solution is finally withdrawn
when the acid in it is as much saturated with ammonia as is considered practicable;
and the solution is afterwards treated by known processes for purifying crystal-
lising and separating the sulphate of ammonia.
I find it advantageous to have the acid solution in a heated state and if the
gases themselves do not impart sufficient heat I cause steam to be blown into the
solution in the vessel or vessels. If necessary the quantity of water is maintained
by adding what may be required to compensate for evaporation.
In some of the modifications of which the apparatus is susceptible diaphragms,
disks, or screens are arranged to be continually dipping vertically into and rising
out of the acid solution or water; and in other modifications the diaphragms,
disks, or screens, which are vertical are stationary and the acid solution or water
is continually pumped up and distributed over their upper ends so as to run down
and keep their surfaces constantly wet.
One very simple and inexpensive mode of constructing the series of rotating
disks, diaphragms, or screens consists in stringing upon the shaft a number of
boards of the shape of the part between the two bars, 14, 15, in Figure, 1, these
boards being arranged on the shaft in a helical series and being separated from
each other by boss or centre pieces of suitable thickness. Narrow spaces are thus
formed between the successive boards and the gases passing through these spaces
are brought repeatedly into close contact with the wetted surfaces.
Haring thus particularly described ny said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel aud

page_text: original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
1. The arrangements of apparatus for separating ammonia from blast-furnace
and other gases or vapors in which these are led over, through, or in contact with
disks, diaphragms, or screens, moved so as to have their surfaces repeatedly wetted
by an acid solution substantially as hereinbefore described.
2. The arrangement of apparatus for separating ammonia from blast-furnace and
other gases or vapors in which these are led through perforations or openings in a
series of stationary vertical disks, diaphragms, or screens kept constantly wetted
by an acid solution repeatedly distributed over their upper ends substantially as
hereinbefore described.
hand
In witness whereof, I, the said Gavin Chapman, have hereunto set my
and seal this Eighth day of June in the year of our Lord One thousand
eight hundred and eighty-two.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
GAVIN CHAPMAN (L.S.)