CERTAIN IMPROVEMENTS ON FURNACES FOR THE CALCINATION, SUBLIMATION, OR EVAPORATION OF ORES, METALS, AND OTHER SUBSTANCES
Year: 1828

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BRUNTON, of Leadenhall Street, in the City of London, Civil Engineer, send
greeting.
WHEREAS His. most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-first day of February, in the ninth year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, the said
William Brunton, His especial licence, that I, the said William Brunton,
my executors, administrators, and assigns, or such others as I, the said
William Brunton, 'my exors, adññors, and assigns, should at any time agree
with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "CERTAIN IMPROVEMENTS ON FURNACES FOR THE CALCINATION,
SUBLIMATION, OR EVAPORATION OF ORES, METALS, AND OTHER SUBSTANCES;" in
which said Letters Patent there is contained a proviso obliging me, the said
William Brunton, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of my said Invention, and
in what manner the same is to he performed, and to cause the same to be
inrolled in His Majesty's High Court of Chancery within two months
next and immediately after the date of the said recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and
at large appear...

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Brunton, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, is described and
ascertained as follows (that is to say):-
I construct the furnace or space into which the ores, metals, or other
substances are to be introduced for the purpose of calcination, sublimation, or
evaporation, of a circular form, having the fireplace, which I make of the
common construction used in calcining furnaces, on one side of the said
furnace, and the flue or opening for the conveyance of the smoke to the
chimney on the opposite side of the said furnace. The floor or bottom of the
said furnace I also make of a circular form, and higher in the middle than
at the edges. I cause the said bottom, with the materials laid upon it, to
revolve round the centre within the said furnace; and in order that it may
have sufficient room to do so, I make the said bottom somewhat less in
diameter than the inside of the furnace. The roof of the furnace is a flat arch
or dome, built upon and abutting against the side walls of the furnace, after
the same manner as is usually practised in building calcining furnaces. In the
middle of the roof, over the centre of the revolving bottom, a hole is left, into
which is fixed a hopper or binn, of cast or wrought iron, to receive the ores,
metals, or other substances to be calcined, sublimated, or evaporated, which,
falling through the said hole in the roof of the furnace, form a conical heap
upon the middle of the revolving bottom. On the side of the furnace next to
the flue and farthest from the fire, I fix a succession of pieces of metal, or other
eligible material, which I call scrapers, close over but not touching the surface, of
the said revolving bottom; and I give the said scrapers such a degree of obliquity
that the ores, metals, or other substances resting on the bottom, being urged by
its revolving motion against the said scrapers, be thereby moved further from the
centre; that is, the first scraper being placed so as to enter into the heap formed
in the middle will at every revolution of the bottom separate a quantity from the
heap and form it into. a concentric ring farther from the centre; and the second
scraper being placed in like manner to the first concentric ring as the first
scraper is to the heap, will at every revolution of the bottom take from the
first, and form a second concentric ring; and so on in succession, until by the
last scraper the ores, metals, or other substances. are directed over the edge or
margin of the said revolving bottom and fall through a hole. into. the tub
or- receptacle, in proportion to the rapidity with which the bottom is made. to
revolve. From the centre of the revolving bottom. a spindle or shaft of iron is
made to pass up through the heap. and the middle of the hole in the roof of the
furnace, and also into the hopper or binn, on which shaft I fix several cross pieces:
of iron, which revolving with the bottom agitate and prevent the ores, metals,

page_text: or other substances in the hopper from clogging or settling together. Thus,
by the action of this shaft, the revolving of the bottom, and the operation of the
scrapers, the whole of the ores, metals, or other substances, are distributed
over the bottom of the furnace, and made to pass in succession through the
process of calcination, sublimation, or evaporation. The degree of heat given
to the ores, metals, or other substances, and the time they are exposed to it,
are regulated by the speed at which the bottom revolves, and the intensity at
which the fire is maintained.
I desire that it be distinctly understood that, though I have, for the
purpose of illustration, described a furnace with a fireplace on one side and a
flue on the other, and having a roof with a hole in the middle of it, with
a hopper or binn fixed upon the same, yet that these constitute no part of my
Invention, as they are in common use; nor does it consist in making the
furnace of a circular form, nor in the application of heat passing from the fire-
place through the furnace to the flue, nor in permitting atmospheric air to
enter the furnace in any particular place, though it will be best admitted on
the side next to the fire. But my Invention consists exclusively in making the
bottom of the furnace, whether made of bricks, tiles, iron, or other suitable ma-
terials, moveable round its centre, and in the application of the fixed scrapers;
and also in the application of the shaft, with the cross bars revolving in the
hopper, thereby producing the introduction, the distribution or spreading,
the uniform heating, and the ultimate discharge of the ores, metals, or other
substances, when calcined, sublimated, or evaporated. And that the materials
to which my improved furnace is applicable are the ores of silver, copper, tin,
lead, iron, and zinc, and the metals, regules, or substances obtained from
such ores, or any of them, in the progress of smelting or refining the same;
all such ores, metals, regules, or substances, being reduced to a size adapted
for calcination, sublimation, or evaporation, previous to their being submitted
to the operation of my said furnace or calciner.
I now proceed to describe the manner in which the parts specified as consti-
tuting my Invention are constructed and applied. I construct the moveable
bottom of the furnace of fire brick, built or set upon a strong frame of cast
iron, which I make of the same form as the surface of the bottom, that is,
rising in the middle about one twelfth part of its whole diameter, and is com-
posed of arms extending in radii, like the arms of a common wheel, from the
nave or centre, which fits upon an upright shaft or pivot upon which it is
supported. The outer end of the arms are attached to and support a cast iron
ring, which, standing above the upper edge of the arms, and bevelling outward,
forms a ledge or abutment for the bricks all round the circumference of the

page_text: 'bottom. I also lay concentric rings of cast iron on the upper side of the arms
in notches prepared for them, of different diameters, for the support of the fir
bricks of which the bottom is composed. The shaft or pivot of the revolv
ing bottom is maintained in an upright position by being supported in a strong
frame or socket of cast iron built into the foundation of the furnace, and in
which frame or socket the shaft or pivot, resting upon its lower end, is easily
moveable round its centre. In the upper end of the upright shaft or pivot 1
form a square hole, into which I fix an iron shaft, which, standing up through
the middle of the whole in the roof of the furnace and into the hopper, where
upon the said shaft I fix several cross bars or pieces of iron, which, by revolving
amongst the materials in the hopper, keeps them loose, and cause them to fall
down and regularly to supply the place of those which by the operation of the
scrapers are detached from the heap. To the under side of the said arms
constituting the frame for the support of the bottom of the furnace, I attach a
bevel wheel, with its teeth downward, which is driven by a pinion fixed upon
a lying shaft projected under the bottom of the furnace, and turned round by
manual labour, or any convenient mechanical power, at such degrees
of velocity as the ores, metals, or other substances to be calcined, sublimated,
or evaporated, may require, according to their respective natures and qualities.
In order to prevent the atmospheric air from entering the furnace by the
space or interstice left between the outside of the revolving bottom and the
inside of the furnace, I enclose the space below the said revolving bottom, and
introduce the lying shaft through a hole suited to its diameter. I also leave
another opening into the said said space sufficiently large for a man to get into
the wheelwork, but which is closed while the furnace is at work. Or I
accomplish the same purpose by fastening to the lower edge of the ring which
is attached to the outer end of the arms a ring or hoop of sheet iron, nine
inches broad, which revolves in a trough or channel formed in the brickwork
of the sides of the furnace underneath the margin of the revolving bottom,
which channel is filled with sand, by which means the air is prevented from
entering the furnace by or through the space left between the exterior diameter
of the revolving bottom and the inside diameter of the furnace.
. I construct the scrapers of cast iron, about eight inches high and ten inches
long, and about nine inches asunder; and I cast the whole in one piece,
together with a strong bar or plate, also of cast iron, capable of supporting
them and of resisting the action of the ores, metals, or other substances, when
pressed against the scrapers by the revolving of the furnace bottom. I place or
cast the scrapers upon the said bar or plate at an angle of about sixty degrees
to the direction of the length of the said bar or plate, taking care that the ends

page_text: of the scrapers against which the materials will be urged shall be made with
edges, and be nearer to the centre of the bottom than the other ends of
such scrapers. The said bar or plate, with the scrapers attached to it, is
introduced into the furnace through an opening in the side wall over the hole
through which it is intended the materials shall fall into the tub or receptacle,
and is supported on the outside of the furnace by being screwed to a strong
piece of cast iron built into the foundation of the furnace, and at a convenient
height, presenting a suitable flanch for this purpose. I prefer fixing the said
bar or plate, with the scrapers, to the flanch by screw bolts and glands or cross
bars, because this mode affords a convenient means of adjusting the scrapers
to the revolving bottom, (that is to say,) that the first scraper shall be suffi-
ciently near the centre of the bottom to remove by each revolution the intended
quantity, and that the last scraper shall sufficiently discharge the ores, metals,
or other substances from the margin of the bottom as it revolves, so that no
part thereof lying on the bottom shall fall over or be discharged at any other
part of its revolution. And that the scrapers be placed as near to the surface
of the bottom as they can, without rubbing or touching it, care should be
taken to make the surface of the revolving bottom true or concentric with its
shaft or pivot, and for that purpose proper attention must be given to the
building the same under a fixed board or trammel, to which the upper surface
of the bottom, when turned round, should conform.
In witness whereof, I, the said William Brunton, have hereunto set
my hand and seal, the Seventeenth day of April, in the year of our
WILLIAM BRUNTON. (L.S.)
AND BE IT REMEMBERED, that on the Seventeenth day of April, in
the
year of our Lord 1828, the aforesaid William Brunton came before our
said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Inred the Twenty-first day of April, in the year of our Lord One
thousand eight hundred and twenty-eight.