IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID
Year: 1857

page_text: LETTERS PATENT to Frank Clarke Hills, of Deptford, in the County of
Kent, Manufacturing Chemist, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF SULPHURIC ACID."
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills at
the Office of the Commissioners of Patents, with his Petition, on the
6th July 1857.
1, FRANK CLARKE HILLS, of Deptford, in the County of Kent, Manu-
facturing Chemist, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID," to be as follows:-
My first improvement consists in a method of burning the oxide of iron
material which has been used in purifying gas, and which is combined with
impure sulphur and other impurities, so as to make sulphuric acid. I effect
this in the following manner:-I construct a furnace, to stand heat, of fire
bricks and tiles. The fire tiles are placed one above another, and are supported
at the sides by fire bricks, leaving spaces of about 5 inches between the tiles,
so as to form a series of shelves, on which the said oxide of iron material is
to be burnt. The back end of the bottom shelf connects to the back end of

page_text: the next shelf over it, forming a continuous flue or passage, so that any gas
formed by the burning material will pass along the bottom shelf, over the
material, from the front to the back of the furnace, when it will rise to the
second shelf through the connection between the two shelves, and then pass
along the second shelf, from the back to the front, and then, by a side
descending flue near the front of the furnace, will descend under the bottom
shelf, and will then pass along to the back of the furnace, when it will rise
by a side or back flue to the back part of the third shelf, it will then pass
upwards from shelf to shelf in a zig-zag course, from front to back of the
furnace, and vice versa, until it arrives at the last shelf or top of the furnace,
from whence it will pass in the usual way to the chamber. The furnace at
starting should be made red hot by burning coke, &c. on the shelves. When
the furnace is hot enough, the coke, &c. should be withdrawn, and the oxide
of iron material is to be put on the four lowest shelves, supposing the furnace
is constructed of 7 or 8, thus leaving three or four shelves above for the gas
to pass over before entering the chamber. Air is to be admitted at the ends
of the shelves, which can be regulated by sliding doors at the fronts of the
shelves, to effect a perfect combustion of the sulphur, and to convert all the
carbonaceous matter into carbonic acid. Other materials containing sulphur,
as mundies, pyrites, &c., may be used in conjunction with the said oxide of
iron material. The requisite quantity of nitre for converting the sulphurous
acid into sulphuric acid may be used in any convenient way, and is well
understood.
My second improvement is for the use of the said oxide of iron material for
making sulphuric acid.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frank Clarke Hills in the Great Seal Patent Office on the
6th January 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
CLARKE HILLS, of Deptford, in the County of Kent, Manufacturing Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of July, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said

page_text: Frank Clarke Hills, Her special licence that I, the said Frank Clarke Hills,
my executors, administrators, and assigns, or such others as I, the said Frank
Clarke Hills, 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," upon the condition (amongst others)
that I, the said Frank Clarke Hills, my executors or administrators, by an
instrument in writing under my, or their, or one of their bands 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 Frank Clarke Hills, do hereby declare
the nature of the 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, that is to say:-
My Invention of improvements in the manufacture of sulphuric acid
relates, firstly, to the material employed to supply the sulphur for the
formation of the acid; and, secondly, to a peculiar method of using the said
material for the said purpose of making sulphuric acid.
The material which I employ to supply the sulphur required for the
formation of the acid is the oxide of iron material which has been used in
the purification of coal gas, and has thereby become combined with sulphur.
To manufacture sulphuric acid from this material, all that is requisite is to
put it into any kind of furnace in which the sulphur may be burnt off
by means of heat, and the resulting sulphurous acid formed be taken in
the usual way into the condensing chambers; but I prefer to burn off the
sulphur from the said material in the following manner :- I construct a
furnace, shewn in section in the accompanying Drawing. a, a, is the
furnace, composed of fire bricks, to stand a great heat, and having a series of
shelves b, b, composed of fire tiles, and ranged one above another, and sup-
ported at the sides by fire bricks, leaving a space of about 5 or 6 inches
between the tiles forming the shelves, and on these shelves is placed, in thin
strata, the said oxide of iron material to be burnt. The spaces between the
shelves are connected together by apertures c, formed at the back and front
ends alternately of the shelves, forming a continuous flue or passage, so that,

page_text: any gas formed by the burning material will pass along the bottom shelf,
over the material laying thereon, from the front to the back of the furnace,
when it will rise to the second shelf through the connection or opening
between the two shelves, and then pass along the second shelf from the back
to the front, and then, by a side descending flue d, near the front of the
furnace, will descend under the bottom shelf, and will then pass along to the
back of the furnace, when it will rise, by a side or back flue e, to the back
part of the third shelf, it will then pass upwards from shelf to shelf in a
zig-zag course from back to front and from front to back of the furnace until
it arrives at the last shelf or top of the furnace, from whence it will pass in
the usual way to the chamber. The furnace at starting should be made red
hot by burning coke, &c. on the shelves. The coke should then be withdrawn,
and the oxide of iron material be put on the four lowest shelves, supposing
the furnace is constructed of seven or eight, thus leaving three or four shelves
above empty for the gas to pass over before entering the chamber. Air is
to be admitted at the ends of the shelves (which can be regulated by sliding
doors ff) to effect a perfect combustion of the sulphur, and to convert all
the carbonaceous matter in the material into carbonic acid. Sulphur, or
material containing sulphur, as mundic or pyrites, may be used in conjunction
with the said oxide of iron material. If sulphur is used, it should be mixed
with the said material; but if mundic or pyrites are used, they should be
reduced to a powder before mixing with the material. The requisite quantity
of nitre for converting the sulphurous acid into sulphuric acid may be used
convenient way, and is well understood.
in any
Instead of keeping the shelves hot merely by the heat generated by the
burning of the said materials, a fireplace may be formed at the bottom of
the furnace under the lower shelf, and flues may be carried from it up the
sides and over the top of the series of shelves; and by burning coke, &c.
in the said fireplace the furnace may be heated and kept hot, to burn off the
sulphur from the said material.
Having thus described the nature of my Invention, and the manner of
carrying it into effect, I claim in respect thereof,-
Firstly, the employment of oxide of iron material which has been used for
the purification of coal gas to furnish the sulphur required in the manufacture
of sulphuric acid.
Secondly, the mode of burning off the sulphur from the said oxide of irou
material for the manufacture of sulphuric acid, as aforesaid, in a furnace
having a series of shelves ranged one above another, to receive the oxide of

page_text: iron material in thin strata, and which shelves are to be kept red hot, with a
communication from them to the condensing chamber, and also having
apertures with regulators for the admission of air to the shelves, as herein
above described.
In witness whereof, I, the said Frank Clarke Hills, have hereunto set
my hand and seal, this Fifth day of January, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
THOMAS IIILLS,
Chemical Works, Deptford.
F. C. HILLS. (L.S.)