IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID AND IN APPARATUS CONNECTED THEREWITH
Year: 1870

page_text: LETTERS PATENT to Peter Spence, of Newton Heath, Manchester, in
the County of Lancaster, Manufacturing Chemist, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID AND IN
APPARATUS CONNECTED THEREWITH."
Sealed the 21st February 1871, and dated the 27th October 1870.
PROVISIONAL SPECIFICATION left by the said Peter Spence at the
Office of the Commissioners of Patents, with his Petition, on the
27th October 1870.
I, PETER SPENCE, of Newton Heath, Manchester, in the County of
Lancaster, Manufacturing Chemist, do hereby declare the nature of the
said Invention for " IMPROVEMENTS IN THE Manufacture of SulPHURIC ACID
AND IN APPARATUS CONNECTED THEREWITH," to be as follows:-
My improvements relate to the manufacture of sulphuric acid from
the spent oxide of iron used in purifying gas, and consists in a method.
of preparing and burning that material. According to the method now in
use the said oxide is burned in a powdery condition, by my Invention -

page_text: I prepare it for burning by pressing it into bricks or other such solid
masses, which pressing may be effected by any ordinary machinery, as for
instance any of those arrangements which are used in the manufacture
of bricks or tiles. For burning this compressed oxide I propose to use a
furnace of small dimensions, and to furnish it with bars to which a
shaking or lifting motion may be imparted by any ordinary mechanical
means so as to cause the disintegrated material which has been burnt to
fall from them; and I propose to use several of these small furnaces
connected together by channels for conducting the vapour.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Peter Spence in the Great Seal Patent Office
on the 27th April 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
SPENCE, of Newton Heath, Manchester, in the County of Lancaster,
Manufacturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of October, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Peter Spence, Her special license
that I, the said Peter Spence, my executors, administrators, and
assigns, or such others as I, the said Peter Spence, 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 "IMPROVEMENTS IN
THE MANUFACTURE OF SULPHURIC ACID AND IN APPARATUS CONNECTED THERE-
WITH," upon the condition, amongst others, that I, the said Peter Spence,
by an instrument in writingunder my hand and seal, should par-
ticularly 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.

page_text: NOW KNOW YE, that I, the said Peter Spence, 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, and accompanying Drawings, that is to say :-
My improvements relate to the manufacture of sulphuric acid from
the spent oxide of iron used in purifying gas, and consists in a method
of preparing for burning, and burning the same. It has been usual to
effect the said burning by spreading the spent oxide of iron as it comes
from the gas works in a powdery form upon the bed of a furnace, the
heat being afforded by its own combustion, and with frequent stirring, so
as to expose new surfaces until the greater part of the sulphur has been
burned out, the oxide of iron remaining.
By my Invention I take the spent oxide as it comes from the gas
works and press it into bricks, cakes, or other comparatively solid lumps,
and in that condition submit it to the operation of burning. A con-
venient size for the bricks or cakes I have found to be nine inches by four
and a half, and about one and a half inches thick, and the compression
is only such as will enable the bricks or cakes to be handled and passed
into the furnaces without breaking, but not so hard as to hold together
after having been burnt, the object being to get the material upon the
bars in an open condition, so as to allow the passage of air, but sufficiently
loose to allow those portions which have been deprived of their sulphur
to fall away from the pressed masses.
The apparatus for pressing may be constructed of any suitable me-
chanical parts now in use for effecting similar operations, and the
degree of pressure required for bringing the bricks or cakes into the
above described condition will be readily ascertained by a little practice..
The object of burning these bricks or cakes is to convert the sulphur
into sulphurous acid gas, as is well known in the manufacture of
sulphuric acid from spent oxide, and the heat given out in this process
being considerable by the use of furnaces containing large quantities and
which might cause the material to flux, I have provided a remedy by
forming the kilns or furnaces of small dimensions, and have also so con-
structed the bottom or bars of these furnaces that by mechanical means
the bars can be slightly disturbed, by which the oxide of iron as it
powders off the burning bricks is made to fall through the bars, and thus
the passage of air through the burning mass in order to effect combustion
is not interrupted..

page_text: This improved furnace is shewn in the accompanying Drawing, Fig. 1
being a cross section thereof, and Fig. 2 a longitudinal view broken off
and partly in section.
According to the arrangement shewn there are two rows a, b, of these
small furnaces, that is to say, there is what may be called a back row b
and a front row a, and they are continued to the left of Fig. 2, so as to
gain any required number in the series, but one row only may be
employed if desired. At c is the partition wall between the two rows
of furnaces within each of which is built an iron frame d formed with
recesses e within which are situate the fire bars f. The frames & are
furnished with lugs g which carry a shaft h extending through the
outward wall of the furnace, and provided with a lever handle i. Upon
these shafts h are projecting parts k, above which are bars / mounted in
grooves formed in the frames d or situate between projections thereon.
At m are the feed doors to the furnaces at n, doors which may be with-
drawn if necessary for stoking, and at o slide doors for the admission
and regulation of air. At p are boxes built in the ash-pits, and within'
which I place water through any suitable orifice. When it is intended
to charge the furnace, the workman places the pressed material upon a
shovel or other instrument and introduces it through the door m until it
lies on the fire-bars up to the level of the bottom of the said door, and as
the burning goes on as usual the gas passes through channels q into the
longitudinal trunk r, and from thence to the ordinary vitriol chamber.
In charging the furnace, the bricks or cakes are not stacked in regular
form, but are simply conveyed on to the bars, and as the pressed masses
are all nearly the same in bulk and weight, the quantity charged is regu-
lated by the number of bricks or cakes; practically I charge twenty of the
dimensions above mentioned into each furnace every four hours, the area
of the furnace bottom being five feet, and each brick or cake weighs
about five pounds, the depth of the burning mass is from ten to twelve
inches. As the burning goes on the workman as often as he finds it
necessary works the handle i, whereby the projections k are caused to
act upon the bars 1, and thus elevate the fire-bars f, and then allows them
to fall, and by doing this a successive number of times a shaking of the
said bars is effected which causes the burnt portion of the material to
fall through the spaces of the fire-bars, and thus keep them open for the
passage of air.
The burnt material when so falling drops into the water
in the boxes p from which it is periodically removed without causing
any smell or annoyance by means of the door o.

page_text: Having thus described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I desire it to be
understood that I claim as secured to me under the above in part recited
Letters Patent,-
Firstly, and for the purpose above set forth, compressing the spent
oxide into bricks, cakes, or other lumps, previously to their being
burned.
Secondly, the use of a series of furnaces of small dimensions as above
described and provided with fire-bars, which may be raised and depressed
or otherwise agitated for the purpose explained.
In witness whereof, I, the said Peter Spence, have hereunto set my
hand and seal, this Twenty-sixth day of April, in the year of our
Lord One thousand eight hundred and seventy-one.