IMPROVEMENTS IN COOKING AND CULINARY VESSELS AND UTENSILS, AND IN THE APPLICATION AND CONVEYANCE OF HEAT
Year: 1855

page_text: LETTERS PATENT to William Brown, of Glasgow, in the County of
Lanark, North Britain, Merchant, for the Invention of "IMPROVEMENTS
IN COOKING AND CULINARY VESSELS AND UTENSILS, AND IN THE APPLICATION
AND CONVEYANCE OF HEAT."
PROVISIONAL SPECIFICATION left by the said William. Brown at the
Office of the Commissioners of Patents, with his Petition, on the 29th
December 1855.
I, WILLIAM, BROWN, of Glasgow, in the County of Lanark, North Britain,
Merchant, do hereby declare the nature of the said Invention for " IMPROVE-
MENTS IN COOKING AND CULINARY VESSELS AND UTENSILS, AND.IN. THE APPLICATION
AND CONVEYANCE OF HEAT,". to be as follows:-
This Invention relates to the arrangement and construction of vessels,
utensils, chambers, pipes, and other apparatus used for the application and
conveyance of heat, with an external air space, jacket, or division, for the
purpose of aiding the effect of the heat and economising its consumption..
In constructing ordinary kitchen utensils in this way, the utensils are either
lined or covered with sheet iron, tin plate, or other metal, so as to form an air
space.round the vessel, or so far as may be conveniently practicable. This air
space: acts as a powerful non-conductor, and husbands the heat of the cooking

page_text: fire, increasing its effect upon the utensil and its contents. Pans, pots, and
cooking tables are thus greatly increased in efficiency for all the purposes of
cooking; and other apparatus or chambers not used directly upon the fire,
such, for example, as the "American dispatch," the "Dutch oven," and
"Hastener," are also similarly improved by the addition of an encircling air
space. If the lids or covers of the utensils are also fitted up in this way
the effect is heightened still more. Where heat is to be conveyed to some
distance, whether under the form of hot air or steam, the pipes or thoroughfares
are similarly encircled by an air space, for the prevention of wasteful radiation,
condensation, and loss.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Brown in the Great Seal Patent Office on the
22nd May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BROWN, of Glasgow, in the County of Lanark, North Britain, Merchant,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of December, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Brown, Her special license that I, the said William Brown, my.
executors, administrators, and assigns, or such others as I, the said William
Brown, my executors, administrators, or 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 COOKING AND
CULINARY VESSELS AND UTENSILS, AND IN THE APPLICATION AND CONVEYANCE OF.
HEAT," upon the condition (amongst others) that I, the said William Brown,
by an instrument in writing under my hand and seal, 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 William Brown, do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: :
⚫performed, to be particularly described and ascertained in and by the following
:statement in writing, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-
My said Invention relates to the arrangement and construction of vessels,
utensils, chambers, pipes, and other apparatus used for. the application and
conveyance of heat, with an external or encircling air space, jacket, or division,
for the purpose of aiding the effect of the heat and economising its consumption.
In constructing ordinary kitchen utensils in this way, the utensils are either
lined or covered with sheet iron, tin plate, or other metal, so as to form an
air space round the vessel, or so far round it as may be conveniently practi-
cable. This air space or receptacle, which should be so far closed as to prevent
the free circulation of air within it, acts as a powerful non-conductor, and
husbands the heat of the cooking fire, increasing its effect upon the utensil and
its contents. Pans, pots, and cooking tables are thus greatly increased in
efficiency for all the purposes of cooking; and other apparatus or chambers
not used directly upon the fire, such, for example, as the "American dispatch,"
the "Dutch oven," and "Hastener," are also similarly improved by the addition
of an encircling air space. If the lids or covers of the utensils are also fitted:
up in this way the effect is heightened still more. Where heat is to be con-
veyed to some distance, whether under the form of hot air or steam, the pipes
or thoroughfares are similarly encircled by an air space, for the prevention of
wasteful radiation, condensation, and loss.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the several illustrative Figures on my explanatory
Sheet of Drawings, which I have appended hereunto.
Figure 1, on my Sheet of Drawings, is a vertical section or sectional eleva-
tion of an ordinary tea-kettle as arranged, formed, and fitted up according.
to my said Invention. In this instance the kettle is disposed upon a spirit
lamp stand heater; A being a cylindrical case, perforated at the sides, and
supported upon bottom feet, whilst in its bottom is contained a spirit lamp B,
for giving the necessary heat to the kettle C above. The main body of the
kettle C is formed according to the usual plan, and this main body or shell
is surrounded or enveloped on every part except the bottom, and for a short
distance up the sides, and the part whence the spout springs, by an external
metallic sheathing or shell D, so placed as to leave a narrow air space E, F,
between the external surface of the kettle itself and the internal surface of
the surrounding shell. This external cover is so put on that it leaves a
square shoulder at G, by which the kettle rests upon the upper edge of the
lamp stand, the unprotected bottom of the kettle being allowed to project

page_text: down into such stand for due exposure to the heat of the lamp. To extend the
principle as far as is conveniently possible, a similar narrow air space H is
formed in the lid of the kettle, an inner diaphragm piece of metal being added
for the purpose, so as to cover up the space ordinarily left hollow in such lids
or covers. Water contained in a kettle fitted up in this way is heated much
more rapidly and with a much less expenditure of fuel than with the common
kettle, whilst when the contents of the kettle are heated they are retained in a
heated condition for a much longer time than in the common kettle, and the
temperature is uniform, or nearly so, throughout the whole of the contents.
Kettles of this doublé class may also be arranged for being heated on a
common fire or upon à hot plate, care being always taken that the bottom
portion of the kettle. actually exposed to the heat is composed of a single
thickness only of metal, so that the applied heat may get freely and fully at
the contents of the kettle, and when it has got well into the contents," that it
may be properly retained there without wasteful escape.
Figure 2, on my Sheet of Drawings, represents the practical development of
the same system in the example of a stewpan or saucepan as intended for being
heated either by a lamp, a gas jet, a common fire, or a hot plate. Here the
upper portion of the pan is surrounded by an air space A, the lid or cover
having a similar space B. The lower portion of the pan is left single or
undefended by any air jacket, so that the heat may act directly upon it. ' In
ordinary pots and stewpans I have found great advantage from having even
the lid alone made double, and in this way the Invention can be very bene-
ficially applied to common cast-iron pots and goblets.
Figure 3, on my Sheet of Drawings, is a vertical longitudinal section, and
Figure 4 a vertical transverse section, of a simple but most effective portable
oven or baking apparatus, which, as arranged according to my Invention, fulfils,
with the aid of a "hot plate," all the offices of a complicated oven. This con-
trivance is simply a bottomless chamber with a rounded convex top; the whole
being made double, so as to have a complete enveloping air space A. The top
of the apparatus has attached to it a handle B, by which it may be conveniently
lifted. In applying this oven for use upon a hot plate, the article to be cooked,
as a pie, for example, is placed upon the hot plate, and the oven is then placed
over it, so that the pie occupies the enveloped space' C. 'The effect of this
arrangement is, that the baking heat, resulting from the hot plate; is covered
in and retained, so that it acts upon the top and sides of the pie with great
intensity. In this way a baking bath of air is kept all round the pie, and the
cooking operation is performed rapidly and economically. If this apparatus is
placed over any article to be cooked, even without a hot plate, and merely in

page_text: front or on one side of a common fire, the effect is somewhat similar, inasmuch
as the fire heat, although really directed against but one side of the oven, is
transferred all round the object under treatment by the agency of the
enveloping air space. From these reasons burning is avoided, the heating
power is applied with uniformity, and consequent economy.
The same system may be carried out under various structural forms of
cooking utensils with more or less economical effect, and I have merely
selected the particular utensils and apparatus shown in my Drawings as
affording a simple and clear explanation of the principle of my Invention.
The rapid and economical effect of my apparatus under its various forms may
be greatly improved by a judicious selection of the material for the enveloping
cover forming the air space. Practical experience has shewn that if the
external cover, or the part which acts merely as the former of the air
space for the retention of the heat, is made of any polished metal, such as
galvanised iron, the applied heat is much more securely retained, and pre-
vented from radiating wastefully, than if such part is made of ordinary
unprepared metal; and in such cooking chambers as the portable oven, the
American despatch, and others, the greatest amount of benefit is obtained.
front making the interior surface also of polished metal.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I do not confine or restrict myself to the precise details or
arrangements which I have had occasion to describe or refer to, as many
variations may be made therefrom without deviating from the principles
or main features of my Invention; but what I consider to be novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent, is, the application and use in cooking
and culinary vessels and utensils, of an enveloping air space, in the manner
and for the purposes herein-before described.
In witness whereof, I, the said William Brown, have hereunto set my
hand and seal, this Fifth day of May, One thousand eight hundred
and fifty-six..
WILLIAM BROWN. (LS.)