IMPROVEMENTS IN THE MANUFACTURE OF RETORTS, MUFFLES, AND POTS
Year: 1871

page_text: LETTERS PATENT to Alfred Borgnet, of Swansea, in the County of
Glamorgan, Manufacturer, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF RETORTS, MUFFLES, AND POTS."
Sealed the 12th September 1871, and dated the 25th April 1871.
PROVISIONAL SPECIFICATION left by the said Alfred Borgnet at the
Office of the Commissioners of Patents, with his Petition, on the
25th April 1871.
I, ALFRED BORGNET, of Swansea, in the County of Glamorgan,
Manufacturer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF RETORTS, MUFFLES, AND POTS," to be
as follows:-
This Invention relates to certain means of protecting the retorts,
muffies, and pots used in reducing zinc and other ores from the
destructive action of the furnace heat to which they are exposed. I
have already to some extent secured this end under my Patent of April
16th, 1870, No. 1113, by passing currents of air in a direct course through
the walls, floor, or roof of the retorts or muffles.

page_text: By my present Invention, however, I so modify the action of the air
that I ensure a more equable result than heretofore. Instead of making
the retorts, muffles, and pots with simple through passages for the
cooling streams of air, I form lateral openings in the air passages (at
regulated distances apart) for the air to pass out into the furnace. The
diameter of these lateral openings I so graduate that at the comparatively
cool end of the retort, or at the front end at which the air enters the
passages, the lateral openings will be of a minimum diameter, and as
the back end of the retort is neared the capacity of the lateral openings
will increase. Thus where the retort is hottest there will be the
greatest escape of cooling air, and this escape will diminish in proportion
as the severity of heat to which the retort is exposed diminishes. The
passages may be closed or open at their inner ends as thought most
desirable. So also the back of the retort or muffle may be made hollow
by extending the horizontal air passages thereto and causing them to
take a vertical direction. In this case the lateral openings will be con-
tinued, and these may be graduated to regulate the discharge of the
cooling air as explained.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Borgnet in the Great Seal Patent Office
on the 25th October 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
BORGNET, of Swansea, in the County of Glamorgan, Manufacturer, send
grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of April, 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 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, 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,

page_text: and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
RETORTS, MUFFLES, AND POTS," upon the condition (amongst others) that
I, the said Alfred Borguet, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands 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 Scal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alfred Borgnct, 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 Drawing here-
unto annexed, and to the letters and figures marked thereon (that is to
say):
:-
This Invention relates to certain means of protecting the retorts,
muflles, and pots used in reducing zinc and other ores from the
destructive action of the furnace heat to which they are exposed. I
have already to some extent secured this end under my Patent of April
Sixteenth, One thousand cight hundred and seventy, No. 1113, by
passing currents of air in a direct course through the walls, floor, or
roof of the retorts or muffles.
By my present Invention, however, I so modify the action of the air
that I ensure a more equable result than heretofore. Instead of making
the retorts, muflles, and pots with simple through passages for the
cooling streams of air, I form lateral openings in the air passages, at
regulated distances apart, for the air to pass out into the furnace. The
diameter of these lateral openings I so graduate that at the comparatively
cool end of the retort, or at the front end at which the air enters the
passages, the lateral openings will be of a minimum diameter, and as
the back end of the retort is neared the capacity of the lateral openings
will increase. Thus where the retort is hottest there will be the greatest
escape of cooling air, and this escape will diminish in proportion as the
severity of heat to which the retort is exposed diminishes. The passages
may be closed or open at their inner ends as thought most desirable.
So also the back of the retort or muffle may be made hollow by
extending the horizontal air passages thereto and causing them to take
a vertical direction. In this case the lateral openings will be continued,

page_text: and these may be graduated to regulate the discharge of the cooling air
as explained.
In the accompanying Drawing I have shewn my Invention as applied
to several forms of retorts; in some of which the air passages are formed
in the base of the retort, in one, which is cylindrical in cross section, 5
through the crown, base, and sides thereof, and in another through the
crown and back of the.retort.
Figures 1 shew in longitudinal and transverse section a retort with
a central air passage A. formed in the base of the retort and stopped
or closed at the back thereof. This air passage is made semicircular 1
or nearly so in cross section. The air enters this passage at the front or
charging end of the retort, and passes out through lateral openings a,
a¹, a², made at either side thereof, into the furnace in which the retort
is set, thereby carrying off the destructive heat from the retort. These
lateral openings it will be seen are graduated, so that there will be a 1
comparatively small escape of air through the holes a near the front of
the retort, a larger escape through the second group of holes a¹, and a
still larger escape through the group a², where the fire of the furnace is
most intense.
Fig. 2 is a longitudinal section of a retort of a similar form to that 2
shewn at Figures 1, but in this example the longitudinal air passage is
continued by an opening a² through the back of the retort.
Figures 3 are longitudinal and transverse sections of a retort somewhat
like that shewn at Fig. 1, but having two longitudinal air passages A, A,
in the base, each of which passages is furnished with lateral openings for 2
the escape outwards of currents of cooling air; Fig. 4 shews these
passages a² as passing through the back of the retort.
Figures 5 shew in longitudinal and cross section a retort with a
central passage formed in the base thereof, and quadrangular in cross
section. This air passage is provided, like that of Figures 1, with lateral
openings at its opposite sides for distributing the cooling air through
the base of the retort.
Figures 6 shew in longitudinal and cross section a cylindrical retort
with four longitudinal air passages A, which are provided with radial
openings a, a¹, a³, for the escape of the air.
Figures 7 shew in longitudinal and transverse section a retort with
parallel sides, and provided at its base with two air passages A, of circular

page_text: form, in transverse section. In this example the lateral openings are
square instead of circular, as shewn in the Figures already referred to,
but the system of graduated groups is still retained.
Figures 8 shew in longitudinal and transverse section a further modi-
fication in the form of the retort. In this example the air passages A, A,
are made in the crown of the retort, and instead of stopping at the
back these passages bend down at right angles, and extend down the
back as low as the floor of the retort. In the horizontal portion of
these passages the lateral openings are provided in the manner already
explained, but in the vertical portion of the passages the order of the
grouping of the lateral holes is inverted. Thus the largest holes are
nearest the crown of the retort, and the smallest near the floor thereof,
the object being in this, as in all the other examples, to ensure the largest
escape of air at the hottest parts of the retort.
Having now set forth the nature of my Invention of " 'Improvements
in the Manufacture of Retorts, Muffles, and Pots," and 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, providing the
air passages formed in the thickness of retorts (whether in the base, the
crown, or side and end walls thereof,) with lateral openings for the
passage outwards of streams of air admitted to the said air passages in
the manner and for the purpose above explained.
In witness whereof, I, the said Alfred Borgnet, have hereunto
set my hand and seal, the Sixteenth day of October, in the
year of our Lord One thousand eight hundred and seventy-
one.