IMPROVEMENTS IN OVENS FOR BAKING
Year: 1856

page_text: LETTERS PATENT to John Trueman, of 34, Castle Street, Belfast, Ireland,
Baker and Confectioner, for the Invention of "IMPROVEMENTS IN OVENS
FOR BAKING."
Scaled the 29th August 1856, and dated the 20th March 1856.
PROVISIONAL SPECIFICATION left by the said John Trueman at the
Office of the Commissioners of Patents, with his Petition, on the
20th March 1856.
I, JOHN TRUEMAN, 34, Castle Street, Belfast, Ireland, Baker and Con-
fectioner, do hereby declare the nature of tho said Invention for "IMPROVEMENTS
IN OVENS FOR BAKING," to be as follows, that is to say :-
This Invention relates to a peculiar construction and arrangement of oven,
suitable for baking bread, biscuits, or other articles of food, whereby a cheap
and economic oven may be constructed, and a considerable saving of fuel
effected, accompanied with greater cleanliness, since the heat is applied exter-
nally to the oven in place of inside, as is usually the case.
The body of the oven consists of a round or square chamber of wrought or
cast-iron, surrounded by brickwork, a space being left between the brickwork
and the top and sides of the oven for the free circulation of the heated air,
which passes off by a fluc or chimney in the centre above the oven.
The bottom of the oven is laid with thin tiles or slabs of stone, and may
be constructed to draw out bodily or be made stationary, as found most
desirable.

page_text: The oven is heated by a small stove, placed in a space or chamber imme-
diately below the oven bottom, which may be fitted with a deflector, for the
purpose of diffusing the heat more evenly over the entire under surface of the
The stove is supplied with fuel through a suitable door or spout in the
brickwork.
The supply of atmospheric air to the stove is obtained from a number of
radiating air pipes or passages, which open at their converging ends into an air
chamber immediately below the stove grate, whilst their outer ends may be
conducted outside the oven or building to any desired distance. An outlet,
opening into the chimney and fitted with a regulator, serves to carry off the
steam or other vapour before withdrawing the batch.
The weight of the oven is supported on suitable cross bars or girders, passed
into or through the surrounding brickwork. It is proposed to apply a
thermometer to the oven for the purpose of indicating the heat thereof.
The same principle of heating, above described, may be applied also to
continuous biscuit-baking ovens, and the heat may be obtained either from gas
or fuel
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Trueman in the Great Seal Patent Office on the
20th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TRUEMAN, of 34, Castle Street, Belfast, Ireland, Baker and Confectioner, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by. Her Letters
Patent, bearing date the Twentieth day of March, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Trueman, Her special license that I, the said John Trueman, my
executors, administrators, and assigns, or such others as I, the said John
Trueman, 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 OVENS FOR
BAKING," upon the condition (amongst others) that I, the said John Trueman,
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

page_text: 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
dato of the said Letters Patent.
NOW KNOW YE, that I, the said John Trueman, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings and to the letters
and figures marked thereon, that is to say :-
My said Invention relates to a peculiar construction and arrangement of
oven, suitable for baking bread, biscuits, and other articles of food, whereby a
considerable saving of fuel is effected, combined with economy of construction
and greater cleanliness, since the heat is applied externally to the oven in place
of inside, as is usually the case.
The body of the oven consists of a chamber of wrought or cast-iron, of any
desired shape, surrounded by brickwork, a space being left between the brick-
work and the top and sides of the oven for the free circulation of the heated
air, which passes off by a flue or chimney in the contre above the oven.
The bottom of the oven is laid with sheets of iron, carrying a layer of sand
and tiles or slabs of stone, and may be constructed by means of a tray to
draw out tho batch bodily, or be mado on the stationary principle, as found
most desirable, in which latter case an ordinary oven door and fittings will be
required.
The oven is hented by a small stove, placed in a space or chamber imme-
diately below the oven bottom, which may be fitted with a deflector, for the
purpose of diffusing the heat more evenly over the entire inside surface of the
oven or hearth. The stove or furnace is supplied with fuel through a suitable
opening or passage in the brickwork foundation.
The supply of atmospheric air to tho furnace is obtained from a number of
pipes or passages, which open at their converging ends into an air chamber
immediately below tho grate, whilst their outer ends may be conducted outside
the oven or building to any desired distance. A valve, either at the side
or at the top of the oven, communicating from the interior into the space
surrounding the same, allow of the exit of steam and vapor, which then
escapes by the flue or chimney.
The hearth or bottom of the oven is supported on suitable cross bars or
girders, passed into or through the surrounding brickwork. It is proposed
to apply a thermometer to the oven for the purpose of indicating the heat
thereof.
And in order that my said Invention may be more readily understood, I

page_text: -shall now proceed more particularly to describe the same, and for that pur-
'pose I shall refer to the several Figures on the Sheet of Drawings hereunto
annexed, the same letters of reference indicating corresponding parts throughout
all the Figures.
Figure 1 of my Drawings represents a complete front elevation of my
improved form of oven; Figure 2 is a corresponding side elevation of the
same; Figure 3 is a vertical section of the oven; and Figure 4 is a vertical
section of the same, taken at right angles to the section shewn in Figure 3;
Figure 5 represents a sectional plan of the oven, taken above the hearth; and
Figure 6 is a similar section, below the hearth and immediately above the furnace.
A is the body of the oven or baking space, consisting of a chamber of any
desired form and size, fitted with cast-iron sides B, B, and a thin sheet-iron
vaulted or arched top or cover C, which may or may not be covered with non-
conducting material, the whole being supported on fixed cross girders let into
the brickwork.
The baking hearth or floor C of the oven is composed of transverse bars
of T-iron, supporting intermediate plates or sheets of iron, upon which
foundation is placed a layer of sand, and above the sand a layer of tiles.
This oven or baking chamber is surrounded by the brickwork D, and a
space or flue E is left between the brickwork and the top and sides of the
oven for the free circulation of the heated air or flame, which passes off by a
play or chimney F, placed immediately over the centre or crown of the oven.
In Figure 4 the oven is represented as furnished with a tray F¹, on which the
articles to be baked are placed, and which being made to rest, drawn out upon
pullies G, G, carried in the cross girders H, H, and can be drawn out when
required, and when so drawn out it may be supported by the table or frame I,
which is fitted with rollers J, J, for the easier accomplishment of the operation.
K is the outer door, made in one piece, and intended either to be hung with
counterweights or to be made to lift off entirely; L, L, are two inner folding
doors, the top half L, folding up by a counterweight, serves to close the flue at
the top, whilst the lower half folds down, and its extremity may be made to
rest upon the front wall, thereby closing the under flue, whilst free ingress and
egress for the tray are afforded.
The oven is heated by a small stove or furnace M, placed in the space or
chamber N, inmediately below the oven bottom.
This heating chamber is fitted with a fire-brick deflector O, placed imme-
diately over, and at a slight clevation above the furnace, so that the heat may
be more uniformly diffused throughout the heating chamber, as shewn by the
arrows in Figures 3 and 4. The furnace is supplied with fuel through the

page_text: opening or passage P in the brickwork foundation, and the supply of atmo-
spheric air is obtained from the pipes or passages Q, Q, (Figure 6), which
open at their converging extremities in to the ash-pit or air chamber R imme-
diately below the grate, whilst their opposite ends communicate with the
atmosphere in any convenient situation, either inside or outside the building.
S, S, is a small pipe running through the brickwork of the oven, and serving
to indicate the state of the fire without going down to the furnace. A dial
indicator is placed in front of the oven at T, and being furnished
with a handle connected with a lever and rod, the damper U inside the
chimney is casily regulated. V, V, are handles, connected with other dampers,
which serve to close the front flue when the oven is open. A valve W serves
to allow the steam to escape from the interior of the oven into the space
surrounding the same, and thence into the flue and chimney, before
the doors of the oven are opened. X is a thermometer to indicate the heat of
the oven, and thereby enable it to be kept at a regular and even temperature:
The same principle of heating, herein-before described, and illustrated by my
Drawings, is obviously applicable to continuous biscuit-baking, domestic, or
camp ovens, and the heat may be derived from ordinary fuel or from gas. The
heat being generated immediately beneath the contre of the oven, and the
draught tending towards the centre above the oven, a more uniform heating.
action is obtained, and a great economy of fuel effected.
The bread or other articles to be baked being placed on a tray and passed
in and out of the oven in one mass, greatly facilitates the work and reduces the
labor, whilst the bread is not so suddenly set as under the old system, of putting
in one loaf at a time. The shape and color of the bread is greatly improved,
and the loss of weight in baking considerably reduced, as it does not amount,
according to my experience, to more than 2 or three ounces in the four-
pound loaf, whilst the bread keeps fresh for a much longer period than when
baked after the old system.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that 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
doviating from the principles or main features of my said 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,-
First, the general construction and arrangement of ovens for baking bread
and other articles of food, as herein-before described.

page_text: Second, the system or mode of heating bakers' ovens by placing the furnace
outside of or externally to the oven, and immediately below the centre of the
bottom or hearth, and causing the heated air and flame to circulate entirely
round the top, bottom, and sides of the baking chamber, and pass off by a
centre aperture or flue, as herein-before described, and illustrated by my
Drawings.
Third, the application and use of a deflector for the purpose of diffusing and
equalizing the heat beneath the oven bottom, as herein-before described.
Fourth, the system or mode of supplying fresh air to the furnace, as herein.
before described.
Fifth, the peculiar construction and arrangement of baking hearths or oven
bottoms, as herein-before described.
Sixth, the application and use, of a tray running on rollers, and made
capable of traversing in and out of the oven, as required, for the purpose of
introducing or withdrawing an entire batch at one operation, as herein-before
described.
In witness whereof, I, the said John Trueman, have hereunto set my
hand and seal, the Eighteenth day of September, One thousand eight
hundred and fifty-six.
JOHN TRUEMAN. (LS.)