IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID
Year: 1875

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID."-A com-
munication from abroad by C L. Vogt, of Brackwede, in West-
.0
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 29th July 1875
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID," a
communication to me from abroad by C. L. Vogt, of Brackwede, in
Westphalia, in the Empire of Germany, to be as follows.-
This Invention relates to improvements in the manufacture of sul-
phuric acid, and consists in effecting and regulating the admission of air
to the leaden chambers by means of a steam jet in conjunction with a

page_text: jet of air or an air jet in order that the required amount of atmospheric
air necessary for the conversion of the sulphurous acid into sulphuric
acid may thereby be admitted into and due control be obtained over the
working of the leaden chamber or chambers.
In carrying out this Invention a hopper or an equivalent thereto is {
constructed, either of lead or of earthenware, the latter being preferred
as ensuring greater durability, is fixed to the side of the leaden chamber,
and so arranged as to permit a small but sufficiently strong jet of steam
to enter the hopper pipe at the point of Junction of the hopper and its
pipe, and thus to blow off and into the lead chamber and go to create
and carry with it a current or jet of air.
The opening from which the jet of steam issues is of a diameter twice or
thrice as small as the hopper's pipe, and the draught created by the jet
must be sufficiently great as that the desired current of air may be made
to enter the leaden chamber or chambers. By such an arrangement
there will be no want of air in the chamber, and the regular production
of sulphuric acid will only be disturbed by the admission of too great a
quantity of air.
In order to prevent the excess of air it will only be necessary to
enlarge the ejection aperture at the end of the chamber in such measure
that the desired atmospheric pressure remains in the chambers, & that
on opening the pyrites furnaces no air will escapo into them, but that
the furnace gasses will be discharged pretty freely. The latter circum-
stance makes it strongly advisable; in order to avoid loss of sulphurous
acid, to arrange the pyrites furnaces in such a manner as that each
department or compartment of the furnace whilst being charged with a
new charge of pyrites will be separated by means of a damper from
the other departments and compartments, and entirely so from the
leaden chambers.
In carrying out this Invention it will be found that a steam jet of
about 6 millimeters aperture under pressure of about from 3 to 4 atmo-
spheres, arranged as before mentioned, will suffice for the consumption
of about 2,500 kilos. of pyrites in about 24 hours, together with the
conversion of the sulphurous acid resulting.
An analysis of the gases escaping from the leaden chambers will
easily determine what the diameter of the hopper's pine and the

page_text: dimensions of the steam pipe should be, also under what pressure the
steam should be admitted to the steam jet in order that the requisito
quantity of air should be supplied to the leaden chambers.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Scal Patent
Office on the 22nd January 1876
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of July, in the
year of our Lord One thousand eight hundred and seventy-five, in the
39th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, admini-
strators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, 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," a communication
to me from abroad by C L Vogt, of Brackwedo, in Westphalia, in the.
Empire of Germany, upon the condition (amongst others) that I, the said
John Henry Johnson, my executors or administrators, by an instrument
in writing under my hand and scal, 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 John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same 13 to be performed, to be particularly described and ascertained in
and by the following statement, that is to say

page_text: The production of sulphuric acid takes place in such a manner that
sulphur, or latterly almost exclusively pyrites or other sulphuric ores,
are brought into suitable furnaces for burning them, the produced
sulphurous acid being conducted into lead chambers where steam and
liquid nitric acid or nitric acid vapours are also admitted. These gases
being brought together in proper proportion, sulphuric acid will be pro-
duced, the nitric acid imparting oxygen to the sulphurous acid, the latter
thus being transformed to sulphuric acid.
For producing sulphuric acid on a large scale the peculiarity of nitric
acid renders it hardly applicable if the same when bereft of a part of its
oxygen (nitious acid, &c ) did not at the same time possess the quality
to re-oxidize at-once-in the presence of oxygen, thus always regaining
the quality to transform the sulphurous acid into sulphuric acid. Hence
it is possible to produce large quantities of sulphuric acid by means of
but very little nitric acid The oxygen required for this process is
supplied by the atmospheric air, and the former is admitted to the lead
chambers. The atmospheric air is admitted during the burning of the
sulphur or pyrites in the furnaces, not only in sufficient quantity to
create the sulphurous acid but in such superabundance that the nitric
acid will be enabled permanently to effect the above-mentioned addition
of oxygen to sulphurous acid.
So simple as the production of sulphuric acid appears to be, it is
nevertheless connected with considerable difficulties to conduct the
process in such a satisfactory manner as that a sufficient quantity of
sulphuric acid be generated
Although it is quite at the operator's will to introduce into the
chambers such quantities of sulphurous acid, nitric acid, and steam
continuously as may appear necessary, according to circumstances, it is
on the other hand connected with difficulties to introduce the exactly
correct quantity of air (oxygen) into chambers, being dependent upon
and subject to wind and weather, pressure of the air, and temperature,
all of which exert their influence on the iurnaces, and considerable
experience is required immediately to discover each pernicious effect and
to avoid the same by adequate measures. If this is not attended to,
that is, if too much air is admitted to the chambers, or what is far worse,
too little air, then the process of production of sulphuric acid will be
interrupted, and may in case of want of air be brought to a stop
entirely.

page_text: Formerly attempts have been made to effect tho passage of a constant
current of air to the furnaces by means of ventilators. This practice
has however been discontinued as it did not answer, and a remedy has
been sought in enlarging or reducing the apertures for the admission of
air to the furnaces, according to circumstances, and at the same time by
properly regulating the ejection of the gases at the end of the lead
chambers; but notwithstanding great experience and frequent analysis
of the last chamber gases (according to Inventor's experience the gases
ejected from the end of chambers contain from two and a half to five
per cent of oxygen) interruptions in the process of producing the acid
will take place unavoidably.
In order to effect a uniform and regular process of production of acid
in the chambers the following course is adopted, which avoids nearly all
and every irregularity in the formation of acid.-Care must be taken
that the oxygen needed for the transformation of the sulphurous acid
into sulphuric acid in the lead chambers is entirely or for the greater
part introduced, not by way of the sulphur or pyrites furnaces, but
direct to the first leaden chamber, and this is effected by means of steam,
which is at the same time indispensible for the formation of acid, but I
introduce the requisite quantity of air in any other manner. I also alter
or change the particular part or locality where this said quantity of air
is to be introduced without compelling the same to pass over or through
the burning pyrites in the pyrite furnaces should such alterations be
considered more advantageous. To this end a hopper of lead or earthen-
ware, the latter ensuring greater durability, is fixed to the side of the
lcaden chamber and permits a small jet of steam to enter the hopper
pipe at the point of junction of the hopper and its pipe, and thus to blow
off into the lead chamber.
The opening through which the jet of steam issues is of a diameter
twice or thrice as small as the inlet pipe of the hopper, and the draught
created by the jet is such as that a current of air can be made to enter
the leaden chamber. By the adoption of this method there will be no want
of air in the chamber, and the production of sulphuric acid will only be
disturbed by too great a quantity of air.
In order to prevent this superfluity it will only be needed to enlarge
the ejection aperture at the end of the chamber in such measure that
a certain atmospheric pressure remains in the chambers, and that on

page_text: opening the pyrites furnaces no air will escape into them, but that the
furnace gases will be discharged pretty freely. The latter circumstance
makes it strongly advisable, in fact indispensible, in order to avoid loss
of sulphurous acid and to attain the greatest possible yield of acid to
arrange the pyrites furnaces in such a manner as that each department 5
of the furnace whilst charging the same with a new charge of pyrites
will be separated by means of a damper from the other departments, and
cntirely from the leaden chambers
Any particular construction of these pyrites furnaces is unimportant,
the main point is the complete shutting off of the separate division whilst 1
charging with pyrites. The result of experiments made shows that a
steam jet of 6 millimeters aperture under pressure of three to 4
atmospheres will suffice for a consumption of 2,500 kilos. pyrites in
twenty-four hours.
An analysis of the gases escaping from the lead chambers will 1
easily determine the diameter of the inlet pipe and the dimensions or
strength of the steam jet in order to supply the adequate quantity of air
to the lead chambers. This having once been determined for fixed
openings for the air injection into the pyrites furnace and for fixed
ejection openings of the gases at the end of the leaden chambers, then
the process of acid production in the chambers will take place with re-
markable regularity and steadiness.
The burning of the pyrites in the furnaces may be considered more
stable and complete, which may be explained thus, that with this
arrangement no surplus of air need enter the furnaces; hence the latter i
will not have to suffer from refrigeration caused by excess of air not
required for the production of the sulphurous acid, the burning of the
pyrites will thus be better regulated.
In carrying out this Invention attention must be paid to the pyrites
furnaces, inasmuch as no sulphurous acid must be suffered to appear
under the furnace coming through the furnace bars. Should this how-
ever be the case it will bo a sign that the pressure in the furnace and in
the leaden chambers has become too great, which will demand a larger
opening for the escape of the gases to the end of the leaden chambers.
Having now described and particularly ascertained the nature of the
said luvention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to

page_text: be novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is, effecting and
regulating the admission of air into the leaden chambers employed in
and for the production of sulphuric acid by means of a jet of steam
introduced in conjunction with atmospheric air, substantially in the
manner herein described.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and scal, the Twenty-first
day of January, One thousand eight hundred and seventy-
S1X.
J. HENRY JOHNSON. (L.S.)