IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID
Year: 1872

page_text: LETTERS PATENT to Arthur M'Dougall, of the Firm of McDougall
Brothers, Manufacturing Chemists, Manchester and London, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC
ACID."
Scaled the 12th July 1872, and dated the 17th January 1872.
PROVISIONAL SPECIFICATION left by the said Arthur M'Dougall at
the Office of the Commissioners of Patents, with his Petition, on
the 17th January 1872.
I, ARTHUR MCDOUGALL, of the Firm of McDougall Brothers, Manu-
facturing Chemists, of Manchester and London, do hereby declare the
nature of my said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
SULPHURIC ACID," to be as follows:-
Whereas it is found in practice that in burning sulphurous materials
for the manufacture of sulphuric acid impurities are mechanically
carried over by the gaseous current on its passage to the sulphuric acid
chambers, these impurities interfere with the economical production of
the acid, and render it less fit for many useful purposes.

page_text: My Invention consists in causing the sulphurous gas after leaving the
kilns or burners to bubble through an aqueous solution. This may be
readily effected by either pumps or fans.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Arthur McDougall in the Great Seal Patent Office
on the 15th July 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARTHUR
MCDOUGALL, of the Firm of McDougall Brothers, Manufacturing
Chemists, Manchester and London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of January, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Arthur McDougall, Her special license that
I, the said Arthur McDougall, my executors, administrators, and assigns,
or such others as I, the said Arthur M'Dougall, my executors, adminis-
trators, or 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 "IMPROVEMENTS IN THE
MANUFACTURE OF SULPHURIC ACID," upon the condition (amongst others) that
I, the said Arthur McDougall, my executors or administrators, by an
instrument in writing under my hand and seal, 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 Arthur McDougall, 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, that is to say :-
Whereas it is found in practice that in burning sulphurous materials
for the manufacture of sulphuric acid impurities are mechanically

page_text: carried forward by the gaseous current on its passage to the sulphuric
acid chambers, these impurities interfere with the economical pro-
duction of the acid, and render it less fit for many useful purposes.
My improvements consist in providing apparatus whereby the sul-
phurous gas after leaving the kilns or burners can be made to bubble
through water or an aqueous solution by means of suitable pumps or
fans, cither by force or suction, before entering into the sulphuric acid
chambers.
The following is one method, amongst others, in which I carry my
Invention into effect:-The burners or kilns in which I burn the
sulphurous materials used in the manufacture of the sulphuric acid I
construct in the most substantial manner, and bind them on the whole
of their exterior with a tight fitting jacket of cast iron, so that the kiln
or burner is rendered air-tight. The orifices for the admission and
withdrawal of the charge of sulphurous materials are also provided with
strong tight fitting moveable doors. The orifice for the admission of air
is connected by means of suitable pipes with an air pump, which forces
a blast of air through the kiln or burner. The orifice for the outlet of the
sulphurous gas is connected by means of suitable pipes with the washing
apparatus. This consists of an air-tight rectangular vessel partially
filled with water or an aqueous solution. The vessel is divided into
compartments by means of several vertical diaphragms or plates sus-
pended from the top of the vessel and dipping a little below the surfacc
of the liquid contained in it. By this means when the air pump forces
a blast of air through the kiln or burner the sulphurous gas thus
produced, carrying along with it various impurities, is made to pass into
the washing apparatus, where by means of the vertical diaphragms the
gas is compelled to bubble several times in succession through the
liquid, and by this means the impurities are removed or washed out
of the sulphurous gas, which then passes on to the acid chambers
to produce sulphuric acid, after admixture with nitrous gas, as is well
understood.
Having thus described and ascertained the nature of my said Inven-
tion, and the manner of carrying the same into effect, I would observe in
conclusion, that what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the use of an apparatus whereby the sulphurous gas

page_text: after leaving the kilns or burners employed in the production of sul-
phurous acid to be hereafter converted into sulphuric acid, can be made
to bubble through water or an aqueous solution before entering into the
acid chambers, whereby certain impurities are removed, the sulphuric
acid is rendered more fit for many useful purposes, and a considerable
saving in the nitrous gas is effected.
In witness whereof, I, the said Arthur McDougall, have to this my
Specification set my hand and seal, this Ninth day of July One
thousand eight hundred and seventy-two.