Improvements in Baking Ovens.
Year: 1888

page_text: Date of Application, 20th Nov., 1888
Complete Specification Left, 18th Sept., 1889-Accepted, 19th Oct.,
1889
PROVISIONAL SPECIFICATION.
Improvements in Baking Ovens.
A communication from CHARLES FREDERICK HUBBARD, of the City of Toronto,
in the County of York, in the Province of Ontario, Canada.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
The object of the 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; and it
consists, essentially, of a chamber having a stove or independent furnace located
within it, and an air inlet and an air outlet.
In a suitable chamber or oven I place a stove or independent furnace which should
be made perfectly gas-tight and provided with suitable smoke-flues; the one leading
directly from the stove or furnace into the chimney or main fiue and another flue
leading from the stove or furnace into a space which extends across the chamber on
one of its sides. When the draught is turned into the indirect flue the smoke and
heated gases from the stove or furnace pass into this space, thence through an elbow
into another hollow space which extends across and forms the top of the chamber.
From this second space the smoke and heated gases pass through another elbow into
the chimney or main flue. An outer space is formed entirely around the chamber
and is filled with asbestos or equivalent so that no heat shall be lost by radiation.
Suitable shelves are placed and supported within the chamber above the stove or
furnace and there is also a shelf suitably supported within the chamber and located on
one side of the stove or furnace. This shelf is protected by a shield so as to form a
protection for the article being cooked, from the excessive direct heat from the stove
or furnace; the side and bottom spaces being sufficient to allow of the free circulation.
of the heated air through the bottom portion of the chamber next to the stove or
furnace. A bent shield is formed around the bottom side of the flue so as to form an
air-space around it to protect the top of the article being cooked on the shelf from any
excessive direct heat from the flue. An air-flue leads from a point remote from the
stove or furnace to a point where it may connect directly with the flue or indirectly
with it through a space formed on one side of the chamber. I place a damper on the
air-flue and a damper is also placed on the direct flue with the view of being able to
regulate both the circulation of the air and of the smoke for the purpose and in the
manner hereinafter described. Dampers for regulating the admission of fresh air
into the chamber and a fuel-door are also provided. The oven-doors have glass panels
so that the process of cooking may be watched without opening the doors, which
doors are provided with suitable locks by which they may be hermetically closed and
are preferably lined with asbestos.
The manner of constructing the chamber will be understood from the following
description. The outer spaces which are filled with asbestos are formed by the outer
plate which forms one side of the outer casing of the chamber and the plate which
forms the inner side of the said casing. The inner plate is flanged so as to form a
top to the inner space below the flanged top of the plate. The plates which enclose
the air-spaces form two of the inner sides of the chamber and are flanged top and
bottom to close the said air-spaces. The flanged tops and bottoms of these plates
extend over the flanged tops and bottoms of the inner plates which enclose the ends of the
outer spaces next to the hollow spaces and the flanged tops and bottoms of the said
plates are made flush with the flanged tops and bottoms of the inner plates which
close the outer spaces at right angles to the hollow spaces. There is a flanged top
plate fitted into the recess formed by the flanged ends of the other plates and forming

page_text: the top of the chamber. A flange is formed on the top of each of the outer plates
which flanges are designed to form a support for the flanged top plate forming the
outer plate of the top space which is filled with asbestos. The bottom plate of this
space rests on the flanges and forms the top of the hollow space. The bottom of the
chamber is made of metal plates forming a hollow space filled with asbestos. This
bottom rests in an angle plate. All the plates are suitably rivetted or bolted
together as indicated.
Having described the general construction of the parts of this improved oven I shall
refer briefly to a few of the advantages involved in the construction. By placing a
stove or furnace within a chamber 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 without reference to or interfering with the flues of the stove or
furnace I am enabled to regulate with accuracy and despatch the temperature and
circulation of the air through the furnace. By surrounding the chamber with asbestos
and arranging the smoke and air flues within it in the manner described I am enabled
to secure to the fullest extent the effects of combustion within the stove or furnace and
am therefore able to employ a very small stove or furnace for a, comparatively
speaking, large chamber or oven.
Owing to the arrangement of the flues described and to the means specified for
heating the chamber 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.
A further advantage arises from the fact that the fresh air admitted into and
circulated through the oven enables the articles to be baked thoroughly without the
usual loss of weight caused by cooking within a closed oven.
With the view of protecting the goods being baked from the direct radiation from
the furnace within the chamber the lower shelf is lined with asbestos and the shield
also lined with the same material. And although I consider an outlet from the
chamber independent of the furnace preferable, the circulation within this improved
oven might be maintained by forming a damper leading into the ash-pan so that
instead of the air escaping through the before mentioned tube it may be directed
into the ash-pan, from which it will escape through the fire out of the flues of the
furnace.
The ash-pan of the furnace is provided with an independent air-inlet so that the
draught of the furnace may be regulated entirely independently of the air admitted
into the chamber.
Although an enclosed and separate stove or furnace is by far the best means for
heating the chamber constituting this improved oven it is possible to substitute for
the stove a gas jet or jets, and consequently when a furnace is referred to I wish to
include in that term a gas jet or jets arranged for the purpose specified.
Dated this 20th day of November 1888.
COMPLETE SPECIFICATION.
Improvements in Baking Ovens.
A communication from CHARLES FREDERICK HUBBARD, of the City of Toronto,
in the County of York, in the Province of Ontario, Canada.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 the 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; and it consists
essentially, of a chamber having a stove or independent furnace located within it, and

page_text: an air inlet and an air outlet; the whole being constructed and arranged substantially
as hereinafter more particularly explained.
Fig. 1 is a perspective outside view of this improved oven.
Fig. 2 is a sectional front elevation.
Fig. 3 is a cross section x-y in Fig. 2.
Fig. 4 is a sectional detail in perspective showing the manner of connecting the
parts together.
In the drawing A represents a chamber in which is placed a stove or independent,
furnace B which should be made perfectly gas-tight and provided with suitable smoke-
flues. In the drawing is shown two smoke flues; the one marked (leads directly
from the stove or furnace B into the chimney or main flue leading thereto. The.
other flue marked D leads from the stove or furnace B into the hollow space E which
extends across the chamber on one of its sides. When the draught is turned into the
indirect flue D the smoke and heated gases from the stove or furnace pass into the
hollow space E thence through the elbow F into the hollow space G which extends
across and forms the top of the chamber A. From the space G the smoke and heated
gases pass through the elbow H into the chimney or main flue I. An outer space J
is formed entirely around the chamber A and is filled with asbestos so that no heat
shall be lost by radiation. K represents two shelves placed and suitably supported
within the chamber A above the stove or furnace B. L is also a shelf suitably
supported within the chamber A and located on one side of the stove or furnace B.
This shelf L is protected by the shield M shaped substantially as shown in Fig. 3 so
as to form a protection for the article being cooked from the excessive direct heat
from the stove or furnace B; the side spaces a and bottom space b being sufficient to
allow of the free circulation of the heated air through the bottom portion of the
chamber A next to the stove or furnace B. A bent shield N is formed around the
bottom side of the flue D so as to form an air-space around the bottom of the flue D
to protect the top of the article being cooked on the shelf L from any excessive direct
heat from the flue D. An air-flue O leads from a point remote from the stove or
furnace B to a point where it may connect directly with the flue I or indirectly with
the said flue through a hollow space P formed on one side of the chamber A. A
damper is placed on the air-flue O and a damper R is also placed on the flue (
with the view of enabling both the circulation of the air and of the smoke to be
regulated for the purpose and in the manner hereinafter described. Dampers S for
regulating the admission of fresh air into the chamber A and a fuel-door T are
provided as indicated. The oven-doors U have glass panels so that the process of
cooking may be watched without opening the doors which doors are provided with
suitable locks by which they may be hermetically closed and are preferably lined with
asbestos.
On reference to figure 4 the manner of constructing the chamber A will be under-
stood. The outer spaces J which are filled with asbestos, are formed by the outer
plate & which forms one side of the outer casing of the chamber A and the plate e
which forms the inner side of the said casing. The inner plate e is flanged so as to
form a top to the space J below the flanged top of the plate d. The plates f which
enclose the air spaces E and P form two of the inner sides of the chamber A and are
flanged top and bottom to close the said air-spaces (see Fig. 2). The flanged tops
and bottoms of the plates f extend over the flanged tops and bottoms of the inner
plates e which enclose the ends of the outer spaces J next to the hollow spaces E and P
and the flanged tops and bottoms of the said plates f are made flash with the flanged tops
and bottoms of the plates e which close the spaces J at right angles to the hollow spaces
E and P. g is a flanged top plate fitted into the recess formed by the flanged ends of the
plates e and fand forming the top of the chamber A. A flange his formed on the
top of each of the plates d which flanges are designed to form a support for
the flanged platej forming the outer plate of the top space V which is filled with
asbestos. The bottom plate k of this space rests on the flanges h and forms the top of
the hollow space G. The bottom W of the chamber A is made of metal plates forming
a hollow space filled with asbestos. This bottom rests as indicated in Fig. 2 in an

page_text: angle plate X. All the plates herein specified are suitably rivetted or bolted together
as indicated.
Having described the general construction of the parts of this improved oven I
shall refer briefly to a few of the advantages involved in the construction. By placing
a stove or furnace B within a 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 without reference to or interfering with the flues of the stove or
furnace the temperature and circulation of the air through the chamber or oven is
enabled to be regulated with accuracy and despatch. By surrounding the chamber A
with asbestos and arranging the smoke and air flues within it in the manner described
the effects of combustion within the stove or furnace B can be secured to the fullest
extent and a very small stove or furnace can therefore be employed for a comparatively
speaking large chamber or oven.
Owing to the arrangement of the flues described and to 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.
A further advantage arises from the fact that the fresh air admitted into and
circulated through the oven enables the articles to he baked thoroughly without the
usual loss of weight caused by cooking within a closed oven.
With the view of protecting the goods being baked from the direct radiation from
the furnace within the chamber the lower shelf K is lined with asbestos and the
shield N also lined with the same material. And although an outlet from the
chamber independent of the furnace is considered preferable the circulation within
this improved oven might be maintained by forming a damper Y leading into the
ash-pan Z so that instead of the air escaping through the tube O it may be directed
into the ash-pan from which it will escape through the fire out of the flues of the
furnace.
The ash-pan of the furnace B is provided with an independent air-inlet m so that
the draught of the furnace may ɓe regulated entirely independently of the air
admitted into the chamber A.
Although an enclosed and separate stove or furnace is by far the best means for
heating the chamber constituting this improved oven, it is possible to substitute for
the stove a gas jet or jets and consequently when a furnace referred to I wish to
include in that term a gas jet or jets arranged for the purpose specified.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent I declare that what I claim is :-
.1. A chamber having a stove or independent furnace located within it and provided
with an air inlet and an air outlet substantially as and for the purpose specified.
2. A chamber having located within it a stove or independent furnace provided
with an independent flue or flues in combination with an air inlet entering the
chamber in proximity to the stove or independent furnace and an air outlet flue
connecting with the interior of the chamber at a point remote from the stove or
independent furnace and leading to and connecting with the smoke flue of the stove
or independent furnace substantially as and for the purpose specified.
3. A chamber having a casing lined with asbestos and arranged to contain a stove
or independent furnace provided with an independent flue or flues substantially as
and for the purpose specified.
4. A chamber having a casing lined with asbestos and arranged to contain a stove
or independent furnace provided with a direct flue leading to the chimney or main
flue and an indirect flue leading to an air space formed within the walls of the
chamber and communicating with the chimney or main flue substantially as and for
the purpose specified.
5. A chamber having a casing lined with asbestos and arranged to contain a stove
or independent furnace provided with a direct flue leading to the chimney or main
flue and an indirect flue leading to an air-space formed within the walls of the

page_text: chamber and communicating with the chimney or main flue in combination with an
air inlet entering the chamber at a point in proximity to the stove or independent
furnace and an air outlet flue entering the chamber at a point remote from the stove
or independent furnace and leading to and connecting with an air space formed in
the wall of the chamber and communicating with the main flue or chimney
substantially as and for the purpose specified.
6. A chamber having a stove or independent furnace located within it and provided
with an air inlet and an air outlet one or more shelves being located within the
chamber immediately above the stove or independent furnace and one or more shelves
located within the chamber at one side of the stove or independent furnace which
latter shelf or shelves is or are protected from the excessive direct heat of the stove
or independent furnace by a vertical shield substantially as and for the purpose
specified.
7. A chamber having a casing lined with asbestos and arranged to contain a stove
or independent furnace provided with a direct flue leading to the chimney or main
flue in combination with air spaces formed in the vertical walls of the chamber and
connected to a horizontal air-space formed in the top of the chamber by means of
elbows projecting into the chamber the said air spaces being connected to a smoke
flue of the stove or independent furnace substantially as and for the purpose
specified.
8. A chamber heated by a stove or furnace and provided with an air inlet entering
the chamber at a point near the furnace and an air outlet leading from the chamber at
a point remote from the furnace substantially as and for the purpose specified.
9. A chamber heated by a stove or furnace and lined with asbestos substantially as
and for the purpose specified.
10. A chamber made in sections and lined with asbestos in combination with a
stove or furnace for heating the said chamber substantially as and for the purpose
specified.
11. A chamber heated by a stove or furnace and provided with an air-inlet entering
the chamber at a point near the furnace and an air-outlet leading from the chamber
to the ash-pan or pit of the stove or furnace substantially as described.
12. A chamber heated by a stove or furnace and provided with an air-inlet entering
the chamber at a point near the furnace and an air-outlet in combination with a shelf
or shelves lined with asbestos substantially as and for the purpose specified.
13. A chamber heated by a stove or furnace and provided with an air-inlet entering
the chamber at a point near the furnace and an air outlet in combination with a shield
lined with asbestos and placed on the smoke-flue leading from the furnace substantially
as and for the purpose specified.
14. A chamber provided with an air-inlet and an air-outlet in combination with an
independent stove or furnace provided with an independent air draught and an
independent smoke-flue the said furnace being so located that the radiation from it
shall heat the air as it circulates through the furnace substantially as and for the
purpose specified.
Dated this 18th day of September 1889.
W. P. THOMPSON & BOULT,
Agents for the Applicant.