IMPROVEMENTS IN THE CONSTRUCTION OF RETORTS, MUFFLES, POTS, AND FURNACES FOR REDUCING ZINC AND OTHER ORES
Year: 1870

page_text: LETTERS PATENT to Alfred Borgnet, of Swansea, in the County of
Glamorgan, Manufacturer, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF RETORTS, MUFFLES, POTS, AND FURNACES FOR REDUCING
ZINC AND OTHER ORES."
Sealed the 16th August 1870, and dated the 16th April 1870.
PROVISIONAL SPECIFICATION left by the said Alfred Borgnet at
the Office of the Commissioners of Patents, with his Petition, on
the 16th April 1870.
I, ALFRED BORGNET, of Swansea, in the County of Glamorgan,
Manufacturer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF RETORTS, MUFFLES, POTS, AND FURNACES
FOR REDUCING ZINC AND OTHER ORES," to be as follows:-
The chief object of this Invention is to regulate the heat of retorts,
muffles, or other like vessels used in the treating or reducing of zinc
and other ores. The Invention also materially assists in protecting the

page_text: retorts from the destructive action of the furnace fires. These results I
attain by forming the retorts or other vessels with air passages running
through the walls, the floor and the roof of the vessels or longitudinally
through the floor and roof, or through the floor only, and connecting
these passages at the back of the retort or vessel when the same are set
in a furnace with a chimney shaft either by a separate connecting flue
or by allowing the back end of the air passages to open direct into the
furnace leaving the front end of the air passages open to the access of
streams of cooling air. By this arrangement a constant draught may
be kept up through the thickness of the retorts, and thus the temperature
of the retorts may be prevented from rising above any determined
degree of heat. The draft through the air passages may be regulated
by means of clay plugs or their equivalents inserted in the front end
of the air passage, which will enable the attendant to determine the
amount of cooling air that shall pass through the passages.
In setting retorts (constructed according to this Invention) in the
furnace, I prefer to arrange them in rows one above the other in a
pyramidal form, the number of the retorts in the row decreasing from
the lowest upwards. This arrangement will cause the gases of com-
bustion to take a zig-zag course in their passage upward. Chimneys
are provided at opposite ends of the furnace. I support the front ends
of the retort on fire-clay saddles (clay luted round their mouths) and
upon horizontal slabs of fire-clay which are bolted to longitudinal iron
bars running across the front of the furnace and built into the masonry
at both ends. The horizontal spaces for each row of retorts is divided
by cast-iron standards into rectangular spaces sufficiently wide to contain
one or more retorts. The back ends of the retorts rest on ledges of
masonry and when not connected with a special air flue are set a
sufficient distance from the wall to allow of the escape of air from their
air passages into the furnace. The horizontal position of the lowermost of
the series of retorts may be reversed, that is to say, placed in the furnace
at an opposite incline to that of the others and with their mouths
opening at the back of the furnace. I find it unnecessary to furnish
the upper rows of retorts with air passages as tho action of the flame
is not so intense at the upper part of the furnace as at the lower
part..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Borgnet in the Great Seal Patent Office on
the 13th October 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
BORGNET, of Swansea, in the County of Glamorgan, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of April, in the year of
our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did for Herself, Her heirs and successors, give and
grant unto me, the said Alfred Borgnet, Her special licence that I,
the said Alfred Borgnet, my executors, administrators, and assigns,
or such others as I, the said Alfred Borgnet, my executors, adminis-
trators, 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 CONSTRUCTION
OF RETORTS, MUFFLES, POTS, AND FURNACES FOR REDUCING ZINC AND OTHER
OBES," upon the condition (amongst others) that I, the said Alfred
Borgnet, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and scals, 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 Patcut.
NOW KNOW YE, that I, the said Alfred Borguet, 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, reference being had to the Drawings hereunto.
anuexed and to the letters and figures marked thereon (that is to
say) :-
This Invention relates to improvements in the furnaces and retorts
for which I obtained Letters Patent bearing date the Twenty-fifth day
of April one thousand cight hundred and sixty-six, and consists, firstly,
in means for regulating the heat of retorts, mufiles, or other like vessels
used in the treating or reducing of zine or other ores with a view to their

page_text: protection from the destructive action of the furnace fires, and, secondly,
in improvements in the furnaces in which the retorts are mounted, the
object being to renew with facility the slabs on which the retorts rest
as they are burned out without stopping the action of the furnace.
The first of these results I attain by forming the retorts or other vessels
with air channels or passages running through the walls, the floor, and
the roof of the vessels, or longitudinally through the floor and roof, or
through the floor only. Theso passages when the retorts or vessels are
set in a furnace connect with the chimney shaft by the back end of the
air passages opening direct into the furnace, and the front end of the
air passages being left open to the atmosphere, a constant draft (capable
of regulation) may be kept up through the thickness of the retorts,
and thus the temperature of the retorts may be prevented from rising
above any determined degree of heat.
In Sheet I. of the accompanying Drawings I have shewn in several
views the manner of applying the first part of my Invention to Belgian
retorts, Welsh pots, and Silesian mufles. These vessels it will be seen
are moulded with through passages variously arranged, but all for one
and the same purpose, namely, the reduction of the temperature of the
same, and the prevention of the destructive action of the fire thereon.
Figures 1 shew a retort with a broad horizontal air passage running
through the floor of the retort from end to end and terminating in
a vertical passage which runs up through the back wall of the retort and
terminates in an open end.
Figures show a retort of a somewhat similar form with the air
passage in the floor running straight through but cuding in a somewhat
contracted opening.
Figures 3 shew six other sections of retorts or pots moulded with air
passages, in one of which air passages are made at equal distances apart
all round the pot.
Figures 4 and 5 show in end view and longitudinal section muflles
furnished through floor and roof with air passages. In Figures 1 these
air passages run into a vertical passage in the back of the muflle and
opening upwards into the furnace. Figures 6 and 7 shew in longitudinal
and in cross section mufiles or pots furnished on all sides with air
passages, which passages open directly into the furnace. The draft
through the air passages I propose to regulate by means of clay plugs

page_text: or their equivalents inserted in the front end of the air passage or
passages. Thus the attendant will be enabled to determine the amount
of cooling air that shall pass through the floor, walls, roof, and back
of the retorts, pots, or muffles.
In setting retorts and muffles, whether constructed according to this
Invention or otherwise, I prefer to arrange them in the furnace in rows
one above the other in a pyramidal form, the lateral space between
the retorts decreasing from the lowest row upwards, which arrangement
will cause the gases of combustion to take a zig-zag course in their
passage upward, and I provide chimneys at opposite ends of the furnace
to equalise the draft, I support the front ends of the retorts all except
the lowest row on firc-clay slabs as usual, and these slabs I hold in
position by a peculiar arrangement of supports which constitutes the
second head of my Invention.
In Sheets II. and III. of the Drawings I have shewn my improved
mode of building up the fronts of furnaces as applied to a zinc furnace,
and in Sheet IV. I have shown the improvements as applied to an
ordinary Belgian furnace.
In Sheets II. and III. Fig. 1 represents a front elevation, partly in
section, of my improved furnace; Fig. 1 a back clevation; Fig. 2 a
transverse section of the same; and Fig. 3 is a partial sectional plan.
In Sheet IV. Fig. 4 shews in transverse section the Belgian furnace
on an enlarged scale with my improvements applied thereto; Fig. 5 is
a partial front view, and Fig. 6 a partial sectional plan shewing the
mode of putting together the parts constituting the front of the furnace.
In all these Figures the same letters of reference indicate the like parts.
The object being to build up the front of the furnace so as to allow
of the displacement of burned out slabs and their replacement by new
ones without stopping the furnace.
In carrying out the second head of my Invention I proceed in the
following manner :-I divide the front space of the furnace longi-
tudinally with plates A of cast iron which extend in two lengths from
end to end of the furnace. These plates I form of the section shewn at
Fig. 4, Sheet IV., where it will be seen that they are also cast with pro-
jections at their front edges in which cottar holes are formed for the
purpose to be presently explained. These plates are set one above the
other at suitable distances apart determined by the height of the retorts,

page_text: pots, or muffles employed in the furnace, and they are held in an inclined
position corresponding to the dip given to the retorts. Upon these cast
iron plates are placed the fire-clay slabs B, B, on which the front ends of
the retorts rest. To keep the slabs in place and to prevent them from
tipping I place over them a band of wrought iron C, which extends across
the front of the furnace, and is secured at its opposite ends in the brick-
work. Between the cast-irou plates A, A, and at equal distances apart,
say, at distances which provide space enough for the reception of two
retorts abreast, I insert vertical cast-iron supports D, which divide the front
of the furnace into a considerable number of rectangular compartments,
and hold down the bands of wrought iron C firmly on the slabs B, B.
These supports are cast with a vertical groove at their inner edge, into
which fits the rebated edge of a vertical fire-clay slab E, which slab,
together with the slabs B, complete the division of the retorts into
groups, as shewn at Figures 5 and 6. The vertical supports D are hold
in place by means of cottars which are driven into the cottar holes in the
plates A, A, as shown at a, a; F, F, are the retorts arranged in pairs,
and having their front ends supported by the slabs 13, 13. The back ends
of the retorts rest on ledges of masonry G, and they are set a sufficient
distance from the wall to allow of the escape of air from their air
passages into the furnace. The inclined position of the lowermost of the
series of retorts may be reversed, that is to say, placed in the furnace
at an opposite incline to that of the others, and with their mouths
opening at the back of the furnace, as shown at F*, Fig. 2, Sheet II.
I find it unnecessary to furnish the upper rows of retorts with air
passages as the action of the flame is not so intense at the upper part of
the furnace as at the lower part. When the retorts are in place, as
shewn at the Drawings, the front of the furnace is to be closed with
clay luting, as indicated by the yellow colour, Fig. 5.
Supposing now it be desired to remove one of the slabs 13 from, say,
the middle of the furnace the luting surrounding the mouths of the
retorts that bear on the injured slab is first to be removed and the
retorts taken out or temporarily supported in a raised position, the
cottars of the two adjacent vertical supports D are then to be knocked
out. These supports being theu free may be readily withdrawn, and
the metal band ✿ being prised up the slab can be drawn from under it
and replaced by a new slab. When this is done the other parts may be
quickly returned to their places, and secured as before.

page_text: Having now set forth the nature of my Invention of " Improve-
ments in the Construction of Retorts, Muffles, Pots, and Furnaces for
Reducing Zinc and other Orcs," and having explained the manner of
carrying the same into effect I wish it to be understood that under
the above in part recited Letters Patent I claim,-
First. Making air channels or passages through retorts, pots, and
muffles, and bringing the same into communication with the draught of
the furnace in the manner and for the purpose above described.
Secondly. Building up the front of reducing furnaces in the manner
and for the purpose above described.
In witness whereof, I, the said Alfred Borgnet, have hereunto
set my hand and scal, the Sixth day of October, in the year of
our Lord One thousand eight hundred and seventy.
5 Witness,
JOHN O. PETERS.
NICHOLAS TREVENA.
(ALFRED) A. BORGNET. (L.S.)