Year: 1892

page_text: Date of Application, 13th Apr., 1892-Accepted, 11th June, 1892
Toronto, Ontario, Canada, Manufacturer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Member of the Institution of Mechanical Engineers, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of this invention is to design a baking oven in which a small fire
shall be capable of heating a large oven at a uniform temperature, which temperature
may be raised or lowered as occasion requires without interfering with the fire, the
said oven to be constructed so that it may be readily taken apart for shipping
purposes, and it consists, essentially, of the construction and arrangement of the
parts hereinafter more particularly explained.
Figure 1 is a perspective outside view of the improved oven.
Figure 2 is a sectional front elevation.
Figure 3 is a cross-section through X Y in Figure 2.
Figure 4 is a sectional detail in perspective showing the manner of connecting
the parts together forming the crown of the oven.
Figure 5 is a sectional plan of a corner, showing the connection between the back
and side of the oven.
Figure 6 is an enlarged perspective detail, showing the means of connecting the
two sides of the oven together.
Figure 7 is an enlarged perspective inside view of the end plate showing the ribs
on which the plates forming the crown of the oven are supported.
Figure 8 is an enlarged perspective view of one end of Figure 7.
Like letters of reference indicate corresponding parts in each figure.
Before describing the construction and arrangement of parts in detail I shall
first explain preferably the general idea of the oven involved in the invention.
A represents the chamber in which is placed a stove or independent furnace B
which should be made preferably gas tight and provided with a suitable smoke
flue C, which connects directly with the air space D, which extends the full height
and length of the compartment forming the oven.
In Figure 2 are shown two stoves or furnaces B, one for each air space D, on
opposite sides of the compartment. Of course one stove might be arranged to
connect with both air spaces, but two stoves are preferred as shown.
The smoke
and heated gases from the stove or stoves B, pass into the air space F, over the
crown of the oven, thence out through the smoke flue G. The interior of the com-
partment forming the oven in this way not only gets the direct heat from the stove
or stoves B, but also derives heat from both its sides and crown and consequently
the oven is uniformly heated.
H represents two shelves placed and suitably supported within the chamber A
above the stoves B. The bottom of the lower shelf of these two is protected by a
shield made of asbestos, mineral wool or other good non-conductor. In order to
retain the heat within the oven so that the full benefit of the fire is secured, the
compartment or oven is surrounded with asbestos casing, and as a good portion of the
invention is involved in its construction I shall now proceed to describe in detail
the manner in which my correspondent puts the casing together.
Each air space D, has an inner sheet metal wall a, flanged at its top (see
Figures 2 and 4) to extend over and rest upon the flanged top of the sheet metal
plate b, forming the other wall of the air space D and also acting as an inner wall
TD 17

page_text: for the space I which is filled with asbestos, mineral wool or other suitable non-
conducting material. The outer wall of the space I is a plain sheet metal plate d,
having on its top and side edges a series of hinge-shaped eye-plates e and i rivetted
or otherwise fastened to it. With the view of strengthening the side formed by
the walls a and d and also with the view of supporting the asbestos or other non-
conductor held in the space there is formed or secured to the inner side of the
plate or wall d a series of narrow plates which project through the asbestos and
butt against the inner wall a thereby bracing the two walls, and at the same time
forming a series of supports which prevent the asbestos or its equivalent sinking to
the bottom of the space.
The back portion of the compartment of oven A has also a space .J filled with
asbestos, the said space being contained between the inner sheet metal plate and
the outer sheet metal plate g the sides of the outer sheet 9 having a series of hinge-
shaped eye-plates h secured to them. These latter eye-plates h are arranged to
interlock with the eye-plates e on the outer side plates d so that the whole may be
locked together by the insertion of a single bolt extending from the top to the
bottom of the outer plates.
K is a curved plate forming the crown of the oven. As will be seen on reference
to Figures 2 and 4 the curved crown of the plate K extends from the top of one
inner wall a to the inner wall on the opposite side of the oven, the said plate K
being bent to rest upon the wall a. Both the said plates K and a together with
the wall bare bent upwardly to be parallel with the wall d the whole of them being
secured together by the bolts or rivets which hold the eye-plates i in position.
The curved plate K forms one side of the air space F while the curved plate L
forms the other side. This latter plate rests upon the flanged end of the plate K
as shown in Figure 4 and forms one side of the space M which is filled with
asbestos, mineral wool or other non-conducting material. The outer wall of the
space M is formed of sheet metal N which is shaped as shown in Figures 2 and 4
and rests upon the plate L. A series of plates are rivetted to the edge plate N
and are arranged to interlock with the eye-plates i rivetted to the top edge of the
outer side plate d.
With the view of providing end supports for the curved plates K L and Na
-ribbed plate O is provided for each end (see Figures 7 and 8) the said ribs being
curved as shown to form supports for the plates K L and N. It will also be
observed that between the ribs which support the curved plates K and L, two or more
apertures are made which are provided with suitable caps and are intended to
enable the air space F to be cleaned out when required. It may be observed here
that the curved or arched space F, greatly facilitates the draft as the smoke and
heated gases flow freely through it.
With the view of ventilating the chamber A and producing a constant circulation
there is made an opening or openings at the bottom of each air space D and it is
protected by a damper Q. When these dampers are opened a downward draft in
the chamber A will be produced which chamber is supplied with fresh air through
dampers R made in the smoke portion S of the front plate. The stove door T and
the ash door U are both made in the same sunk portion S, and the whole are con-
nected by an outer door V, which is provided with a single damper W. The oven
doors X are preferably provided with glass panels so that the process of cooking
may be watched without opening the doors.
By placing a stove or furnace B within the chamber A constructed substantially
as described and having an air inlet and an air outlet for admitting air into the
chamber and discharging it from the chamber my correspondent is enabled to
regulate with accuracy and despatch the temperature and circulation of the air
through the oven and by surrounding the chamber A with asbestos or other suitable
non-conductor and arranging the smoke and air flues within it in the manner
described, my correspondent is able to secure to the fullest extent the effect of
combustion within the stove or furnace and is therefore able to employ a very small
stove or furnace for comparatively speaking a larger chamber or oven. Owing to

page_text: the arrangement of the flues described and the means specified for heating the
chamber A, anything placed in the oven to be baked is evenly affected on all sides
by the action of the heated air and is therefore thoroughly cooked.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is :-
1. A chamber having its two outer sides, back and top lined with asbestos,
mineral wool, or other suitable non-conductor and within said lined sides an air
space having an aperture through its top to communicate with an arched air space
extending over the crown of the said chamber, a smoke pipe or flue extending from
the arched air space, a stove or furnace contained within said chamber and having
a smoke pipe to communicate with the side air space or spaces; substantially as
and for the purpose specified.
2. A chamber having its two outer sides, back and top lined with asbestos,
mineral wool, or other suitable non-conductor, and within said lined sides an air
space having an aperture through its top to communicate with an arched air space
extending over the crown of the said chamber, smoke pipe or flue extending from
the arched space, a stove or furnace contained within said chamber and having a
smoke pipe to communicate with the side air space or spaces, an aperture with
suitable damper between the side air space and chamber near the bottom of the
latter and an aperture with suitable damper between the chamber and exterior
thereof; substantially as and for the purpose specified.
3. A chamber or oven made of plates of sheet metal arranged as described with
a lining of asbestos between them and the corners of the outer sheets having a
series of hinge-shaped eye-plates connected to them and arranged so that the eye-
plates on one sheet shall interlock with the eye-plates on the adjoining sheet so that
the same may be connected together by means of a bolt; substantially as and for
the purpose specified.
4. A chamber or oven connected together substantially as described and having
an air space above its crown formed between the arched or curved plates K and L
and protected by an asbestos lining between the curved plate L and plate M
substantially as and for the purpose specified.
5. A chamber or oven constructed substantially as described and having corre-
sponding plates O at its front and back with curved ribs formed thereon to support
the ends of the plates K and L and N; substantially as and for the purpose
specified.
6. A chamber or oven having its sides formed by double walls filled with
asbestos said walls having a series of narrow plates extending from the outer to
the inner wall to strengthen the same and form supports for the asbestos or other
non-conducting lining; substantially as and for the purpose specified.
7. A chamber or oven constructed substantially as described and having a front
with a sunk portion S in which the stove and ash doors are formed in combination
with an outer door designed to enclose the said stove and ash doors; substantailly
as and for the purpose specified.
Dated this 13th day of April 1892.
ALFRED J. BOULT,
Chartered Patent Agent.