IMPROVEMENTS IN THE MEANS OF AND APPARATUS FOR HEATING, MELTING, BOILING, EVAPORATING, AND OTHER USEFUL PURPOSES
Year: 1863

page_text: LETTERS PATENT to Charles Stewart Duncan, of Inverness Road, Bays-
water, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN THE MEANS OF AND APPARATUS FOR HEATING, MELTING, BOILING,
EVAPORATING, AND OTHER USEFUL PURPOSES."
Sealed the 19th January 1864, and dated the 21st July 1863.
PROVISIONAL SPECIFICATION left by the said Charles Stewart Duncan
at the Office of the Commissioners of Patents, with his Petition, on the.
21st July 1863.
I, CHARLES STEWART DUNCAN, of Inverness Road, Bayswater, in the County
of Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MEANS OF AND APPARATUS FOR HEATING, MELTING, BOILING,
EVAPORATING, AND OTHER USEFUL PURPOSES," to be as follows:-
This Invention consists of certain improvements in the method of and
apparatus for heating liquids or solids, for boiling and evaporating solutions,
and for melting or dissolving animal, vegetable, or mineral matters; tho said
Invention being also applicable to the purpose of annealing glass, porcelain,
earthenware, and such like articles, to the burning of calcareous or siliceous
substances, also to baking ovens and furnaces, where an equalised heat is

page_text: required. I propose to form my apparatus in such a manner that there shall
at all times be a space left between and around two metal or other vessels, of
whatever shape may be required according to the operation to be effected, the
apparatus being constructed with double or false bottom and sides. Within
this space I propose to pour molten lead, zinc, or tin, or any mixture or alloy
thereof. Heat being applied to the outer vessel the molten metal will form the
medium of conduction or radiation to the inner vessel, in which the materials
to be treated are placed, by which means an equalised temperature is
distributed throughout or over the entire surface of the inner vessel, preserving
the materials from any excess of local heat.
In the application of this Invention to the annealing of glass, either plate,
sheet, or flint, it will be necessary to construct the apparatus with a slight
difference of form to the foregoing, yet not departing from the principle of my
Invention; that is, where any flat substances have to be treated, instead of
placing one vessel within another I propose to substitute a strong flat plate or
floor for the inner vessel before mentioned, and beneath it to place a metallic
dish filled with molten metal, thereby distributing the heat over the entire
plate or surface, regardless of the point from which it is first applied and
generated, and therefore supplying heat not by direct contact, but by diffusing
or transmitting it by means of radiation or conduction only. It is thus evident
that any material being thus operated upon can in no way be injured by the
effects of direct local heat, the temperature being so generally distributed,
equalised, and regulated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Stewart Duncan in the Great Seal Patent Office a
on the 21st January 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
STEWART DUNCAN, of Inverness Road, Bayswater, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of July, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Stewart Duncan, Her special licence that I, the said
Charles Stewart Duncan, my executors, administrators, and assigns, or such

page_text: others as I, the said Charles Stewart Duncan, 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 MEANS OF AND APPARATUS FOR HEATING,
MELTING, BOILING, EVAPORATING, AND OTHER USEFUL PURPOSES," upon the condition
(amongst others) that I, the said Charles Stewart Duncan, 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 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 Charles Stewart Duncan, 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:-
My Invention consists of certain improvements in the method of and
apparatus for heating liquids or solids, for boiling and evaporating solutions,
and for melting or dissolving animal, vegetable, or mineral substances; the
said Invention being also applicable to the purpose of annealing glass,
porcelain, earthenware, and such like articles; to the burning of calcareous or
silicious substances, also to baking ovens and furnaces, where an equalized
heat is required.
In order that any said Invention may be thoroughly understood by those
acquainted with the various arts to which the Invention relates, I now proceed
to describe the best means I am acquainted with for carrying the same into
practical effect, as follows:-
I form my apparatus in such a manner that there shall at all times be a
space left between and around two metal or other vessels (one within or above
the other) of whatever shape or material may be required, according to the
operation to be effected, the apparatus being constructed with double or false
bottom and sides, either fixed or moveable. Within this space or double skin
pour molten lead, zinc, or tin, or any mixture or alloy thereof, or any metals
that fuse at a temperature less than that of which the vessels themselves are
composed. Heat being applied to the bottom of the outer vessel by any form
of grate, stove, or furnace, the molten metal will form the medium of induction,
I

page_text: conduction, or radiation to the inner vessel, or upper kiln, furnace, or hot air
chamber, in which the materials to be treated are placed, by which means an
equalized temperature is distributed throughout or over the entire surface of
the inner vessel or hot air chamber, preserving the materials from any excess
of local heat.
In the application of this Invention to the annealing of glass, either plate,
sheet, or flint, it will be necessary to construct the apparatus with a slight
difference of form from the foregoing, yet not departing from the principle of
my Invention; that is to say, where any such substances have to be treated,
instead of placing one vessel within another, I substitute a strong plate or
covered floor for the inner vessel before mentioned, and beneath it I place a
metallic dish filled with molten metal, thereby distributing the heat over the
entire plate or surface, without reference to the point from which it is first
applied and generated, and therefore supplying heat not by direct contact but
by diffusing or transmitting it by means of radiation, induction, or conduction
only. It is thus evident that any material being thus operated upon can in no
way be injured by the effects of direct local heat, smoke, or firing, the
temperature being so generally distributed, equalized, and regulated.
This Invention is also applicable to raising the temperature of cold air (and
increase its superheated or dynamic force) to above 350 degrees Fahrenheit,
for the purpose of motive power.
The vessels in all cases to be supplied with the ordinary taps or cocks for
service and withdrawal of the molten metal and materials in the inner vessel.
The inner vessel may be raised so as to be completely or partially removed
from the molten metal, in order to modify the degree of heat as required.
This operation may be effected by means of screws working in the flanges of
the vessels, or by levers or chains and pulleys.
For heating conical pots or crucibles I apply in lieu of a solid flat plate
a perforated plate or network, into the openings of which the pots or crucibles
may be seated.
Having now described the nature of my said Invention, and the manner in
which the same is to be performed, I would remark, in conclusion, that I do
not limit myself to any preciso configuration of apparatus or parts thereof, as
the same may obviously be varied to suit the particular purpose to which it is
to be adapted; but what I claim as my Invention, and therefore desire to be
secured to me by the herein in part recited Letters Patent, are the " 'Improve-
ments in the Means of and Apparatus for Heating, Melting, Boiling, Evapo-
rating, and other Useful Purposes," consisting in the application of molten

page_text: metal between two vessels, substantially in the manner herein fully described,
for the purposes set forth.
In witness whereof, I, the said Charles Stewart Duncan, have here-
unto set my hand and seal, this Thirteenth day of January, in the
year of our Lord One thousand eight hundred and sixty-three.
Witness to the signature of C. S. Duncan,
L. J. WETHERELL,
Clerk to Messrs. Prince & Co.,
Agents for Patents,
4, Trafalgar Square,
Charing Cross.
AN.
(L.B.)