IMPROVEMENTS IN BAKING OVENS
Year: 1880

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the City
of London, Patent Agent and Consulting Engineer, for an Invention of
"IMPROVEMENTS IN BAKING OVENS." A communication from abroad by
Carl Theodor Seidel, of Dresden, Saxony, Baker.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 1st March 1880.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN BAKING OVENS." [A com-
munication from abroad by Carl Theodor Seidel, of Dresden, Saxony, Baker.]
In baking ovens as hitherto constructed there has been a special objection,
particularly in baking white bread, namely, the decreasing heat, without any means
for increasing it during baking, produces from a given weight a bread of smaller
size and of an inferior appearance.
This objection is not only overcome by the improved oven, which forms the
subject of the present Invention, but this oven also offers the additional advantage
that if necessary the baking process may be continued without interruption, and
that with the same fire with which the oven is heated, a cooking oven for general
cooking purposes, and a steam vessel are heated, the latter supplying steam or
vapor to the baking chamber, by which steam or vapor the appearance of the
bread is much improved.
In the improved oven the baking chamber is filled and emptied through an
opening at the front or end. Above this opening the grate or hearth is situated,
and between the grate and the said opening is the ash pit or box. The fire is led
from the grate along the top or crown of the baking chamber, at the end of which
the fire or heat descends. At this point is a cross-channel,-into-which-any-ashes-or-
particles of combustion will deposit, and from which they may be removed by a
side door. The heat returns underneath the bottom of the baking chamber, and
escapes by a funnel or chimney. The steam vessel is heated by the fire of the
which is directly underneath such steam vessel. The baking chamber, which
may be of sheet iron, is covered for its entire length and width with a layer of fire
bricks or slabs, and in order to free the baking chamber from the weight of this
oven,
Drion G27

page_text: layer, crossbars of T iron are fitted resting on the side walls of the oven. Between
the layer of fire bricks or slabs and the top of the baking oven a layer of asbestos
or other suitable refractory non-conducting material is placed for the purpose of
effecting a uniform development or penetration of the heat into the baking
chamber, and with the same object this layer of asbestos or such like material is
made thicker at the front than at the rear. A similar layer of asbestos or such
like material is placed at or underneath the bottom of the baking oven, but the
reverse of the upper layer; this layer is thickest at the rear end, and decreases in
thickness towards the front of the oven. By thus providing an intermediate layer
above and underneath the baking chamber of different thickness in the different
parts of the oven, a uniform heat is created in all parts of the interior of the baking
chamber.
In order to distribute the heat or fire underneath the baking oven as uniformly
as possible, the oven is supported by sheet iron or cast iron supports, which form
parallel channels or flues. These channels or flues are curved towards the outlet
end, so that all parts of the bottom of the baking vessel are uniformly touched by
the heat or fire.
The sides of the baking vessel are not exposed to the heat, so as to avoid the
burning or "singeing" of the bread.
At one side of the oven are placed a cooking vessel for general cooking purposes,
and a hot water vessel, which are heated by the fire of the oven. A pipe leads the
steam or vapor from the steam vessel into the baking chamber, and other pipes
convey the superfluous steam or vapor from the oven into the air. These latter
pipes may be closed by a cover or lid.
By the construction of oven as hereinbefore
which is highly desirable for baking purposes.
obtained within all parts of the baking chamber.
described a top heat is obtained
A nearly uniform heat is also

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the
27th August 1880.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN BAKING OVENS." A com-
munication from abroad by Carl Theodor Seidel, of Dresden, Saxony, Baker.
In baking ovens as hitherto constructed there has been a special objection,
particularly in baking white bread, namely, the decreasing heat, without any
means for increasing it during baking, produces from a given weight a bread of
smaller size and of an inferior appearance.
This objection is not only overcome by the improved oven, which forms the
subject of the present Invention, but this oven also offers the additional advantage
that, if necessary, the baking process may be continued without interruption, and
that with the same fire with which the oven is heated, a cooking oven for general
cooking purposes, and a steam vessel are heated, the latter supplying the steam or
vapour to the baking chamber, by which steam or vapour the appearance of the
bread is much improved.
Figure 1 is a side view of an oven constructed according to this Invention ;
Figure 2 is an end view of the same; Figure 3 is a longitudinal section on the line
A, B, of Figure 5, looking in the direction of the arrow X; Figure 4 is a cross
section on the line C, D, of Figure 5, looking in the direction of the arrow Y;
Figure 5 is a sectional plan, the left hand half being taken above the baking
chamber, and the right hand half below the same.
In the improved oven the baking chamber a is filled and emptied through an
opening b. Above this opening the grate or hearth c is situated, and between the
grate and the said opening is the ash pit or box d. The fire is led from the grate
along the top or crown of the baking chamber, at the end of which the fire or heat
descends. At this point is a cross channel e, into which any ashes or particles of
combustion will deposit, and from which they may be removed by a side door f.
The heat returns underneath the bottom of the baking chamber, and escapes by a
funnel or chimney h. The steam vessel g is heated by the fire of the oven which
is directly underneath such steam vessel. The baking chamber a, which may be of
sheet iron, is covered for its entire length and width with a layer of fire bricks or
slabs;
and in order to free the baking chamber from the weight of this layer, cross
bars m, m¹, m¹¹, of T iron are fitted resting on the side walls of the oven. Between
the layer of fire bricks or slabs and the top of the baking oven, a layer of asbestos
or other suitable refractory non-conducting material is placed for the purpose of
effecting a uniform development or penetration of the heat into the baking
chamber, and with the same object this layer of asbestos or such like material is
made thicker at the front than at the rear. A similar layer of asbestos or such
like material is placed at or underneath the bottom of the baking oven (but the
reverse of the upper layer); this layer is thickest at the rear end, and decreases in
thickness towards the front of the oven. By thus providing an intermediate layer
above and underneath the baking chamber of different thickness in the different
parts of the oven, a uniform heat is created in all parts of the interior of the
baking chamber.
In order to distribute the heat or fire underneath the baking oven as uniformly
as possible, the oven is supported by sheet iron or cast iron supports n, n¹, n", n₁₁₁,
111

page_text: which form parallel channels or flues. These channels or flues are curved towards
the outlet end in the manner shown in the right hand half of the horizontal section,
Figure 5, so that all parts of the bottom of the baking vessel are uniformly touched
by the heat or fire.
The sides of the baking vessel are not exposed to the heat, so as to avoid the
burning or "singeing" of the bread.
A
At one side of the oven are placed a cooking vessel i for general cooking
purposes, and a hot water vessel k, which are heated by the fire of the oven.
pipe leads the steam or vapor from the steam vessel g into the baking chamber a,
and other pipes o, o¹, convey the superfluous steam or vapor from the oven into the
air. These pipes o, o', may be closed by a cover or lid.
By the construction of oven as hereinbefore described a top heat is obtained
which is highly desirable for baking purposes. A nearly uniform heat is also
obtained within all parts of the baking chamber.
Figures 6, 7, 8, and 9, represents one of the improved baking ovens with several
modifications in its construction. Figure 6 is a front elevation; Figure 7 a
longitudinal section; Figure 8, a cross section on the line A, B, of Figure 7, and
Figure 9, a horizontal section, the upper half being on the line C, D, and the lower
half on the line E, F, Figure 7.
Above the grate c the steam generating vessel g is situated. I sometimes
arrange a damper below the steam generating vessel g, in order to be able to
regulate the heat underneath this vessel, for the more or less generating of steam.
The fire flue or channel in this modification is diminished in cross section by
means of a downward leading arch in such a way that the fire gases or heat are
forced to spread over the entire width of the baking chamber a.
This baking
chamber a is held or carried by iron bolts n, the heads of which take underneath
the upper cover of the chamber a. The bolts n in an upward direction pass
through the flue or fire channel, and are here protected against the destructive
action of the fire by refractory pipes surrounding such bolts, and resting either on
the top side of the baking chamber, or on the refractory plates covering the top
side of the baking chamber. The bolts n in a further upward direction penetrate
through the refractory plates forming the upper part or ceiling of the channel or
flue, and through the 1 iron carrying such refractory plates, which 1 iron rests on
the side wall of the oven; the bolts are secured above such plates by nuts which
rest on washers on the upper side of the said plates.
The irons or girders carrying the refractory plates are inserted into these
plates for protection against fire, and they may be surrounded by slaghair or
mineral wool.
The baking chamber is only partially covered with refractory plates, that is to
say, only towards the grate or hearth, as indicated by the line W, X, Y, in
Figure 9.
I sometimes dispense with the sheet iron or cast iron supports n, n¹, n¹¹, n¹¹,
(Figure 4) underneath the baking oven which form parallel flues or channels, and
I support the chamber by 1 iron underneath the refractory plates at the bottom
of the chamber. The _ irons are supported by the side walls of the oven. By
these means I obtain a flue or channel underneath the baking chamber, without
any partition walls or girders whatever.
I sometimes prefer to lead the heat to the sides of the baking chamber; for this
purpose I construct a channel or flue on each side of the baking chamber, which
flue or channel may either communicate at the front part of the oven with the fire t
chamber near the grate or hearth, in which case this side flue will lead part of the
heat from the front end of the oven to the rear end; or I construct the flue or
channel on the sides of the baking chamber to communicate with the flue or
channel at the rear end, in which case part of the heat will be carried from the rear

page_text: part of the oven to the chimney through these side flues or channels, with which
they must connect.
In order to distribute the top heat over the entire surface of the baking oven
uniformly, and thereby cause a uniform heat within all parts of the baking
chamber, it is of advantage to give the cover of the baking chamber an inclination
at both sides and at the rear end, as is seen in Figures 7 and 8.
I sometimes fit a damper, as indicated by the dotted line p, in Figures 7 and 9.
This damper is sometimes lowered down to the baking chamber, in order to shut
up the heat from the grate towards the middle part of the flue or channel above
the baking chamber, the heat will then go to both sides, as the damper is smaller
in width than the flue.
In order to better preserve or retain the heat within the oven, I lead the fire
gases or products of combustion through several parallel channels or flues through
which the heat or products of combustion must pass before being carried away by
the chimney. The direction in which the heat goes is represented by arrows in
Figure 7.
These flues or channels I construct for the entire width of the oven (see Figure 8)
by means of refractory plates carried by 1 irons, which rest upon the side walls of
the oven.
From the interior of the baking chamber I lead the two vapour pipes o, o¹, in an
upward direction; these pipes may either be shut by means of two conical valves or
the exit of the vapours may be regulated by means of these valves. 9 is the vessel
for generating steam or vapor above referred to; 7 is the pipe leading the steam or
vapor into the baking chamber; k is a vessel or pan for boiling water for domestic
purposes; h is the chimney.
Above the refractory plates which form the ceiling of the flue or channel above
the baking vessel I fill up the oven with any non-conducting material, and above
that the oven is covered with any suitable bricks or plates in the well known
manner.
It is to be understood that the baking chamber may be made of any suitable
material, such, for instance, as cast iron, sheet iron, and steel.
And having now described the nature of the said Invention, and in what manner
the same is to be performed, I declare that I claim,―
First. In a baking oven with top fire, the employment, as hereinbefore described,
of layers of asbestos or other non-conducting refractory material of different
thickness above and underneath the baking chamber, for obtaining a heat as
uniform as possible throughout the baking chamber.
Second. In a baking oven with top fire, the leading of the fire or heat from the
grate along the top and the bottom of the baking chamber, without any flue
channels divided by brickwork, substantially as hereinbefore described.
Third. In the baking ovens herein before described, I claim the decrease of the
cross section of the flue or channel behind the grate for the top fire of the oven,
the construction of channels or flues for the heat or products of combustion at the
two sides of the baking chamber, and the channel or flue underneath the baking
chamber without partitions, all as hereinbefore described and shown in the
Drawings, and for the purposes set forth.
Fourth. In the baking ovens hereinbefore described, I claim inclining the cover
of the baking chamber on both sides and at the rear end, as and for the purpose
herein before described.
Fifth. In the baking ovens hereinbefore described, I claim supporting the cover
of the baking chamber by bolts, covered by -refractory pipes within the flue or
channel, through which these bolts pass, as herein before described and shown in the
Drawings, and for the purposes specified.
Sixth. In the baking ovens hereinbefore described, I claim continuing the flue or

page_text: channel underneath the baking chamber, by several parallel flues or channels before
connecting them with the chimney, as hereinbefore described and shown in the
Drawings, and for the purposes specified.
In witness whereof, I, the said John Clayton Mewburn, have hereunto set my
hand and seal, this Twenty seventh day of August, One thousand eight
hundred and eighty.
J. C. MEWBURN. (L.S.)