Improvements in Baking Ovens.
Year: 1899

page_text: Date of Application, 19th Apr., 1899-Accepted, 27th May, 1899
COMPLETE SPECIFICATION.
Improvements in Baking Ovens.
We, JOHN IRWIN MARSHALL, Manufacturer, and JOHN FAULDS, Mechanic, both
of 60, W. Van Buren Street, Chicago, County of Cook, and State of Illinois,
United States of America, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement;-
This invention relates particularly to what are known as portable continuous
baking ovens; that is to say, ovens which may be transported in a knock-down
form, and may be readily taken to pieces for moving, and which may be fired
while the baking is proceeding.
The objects of the invention are to secure in ovens of this type higher efficiency,
and simplicity and cheapness of construction.
The invention consists in the parts and arrangement of parts as hereinafter fully
described, and which are illustrated in the accompanying drawings, in which
Fig. 1 is a central longitudinal vertical section of the oven;
Fig. 2 is a plan section on the line 2-2 of Fig. 1;
Fig. 3 is a sectional view on the line 3-3 of Fig. 2;
Fig. 4 is a sectional view on the lines 4-4 of Figs. 2 and 3;
Fig. 5 is a sectional view on the line 5-5 of Fig. 1;
Figs. 6 and 7 are details, in perspective, of certain tiles used in the construction
of the oven;
Fig. 8 is a sectional view on the line 8-8 of Fig. 1;
Fig. 9 is a similar view, Fig. 1 showing a modified construction;
Fig. 10 is an elevation of the furnace front;
Fig. 11 is a sectional view on the broken line 11-11 of Fig. 10;
Fig. 12 is a sectional view on the line 12-12 of Fig. 10;
Fig. 13 is a detail plan section on the plane of the grate;
Fig. 14 is a detail section on the line 14-14 of Fig. 13; and
Fig. 15 is a detail section on the line 15-15 of Fig. 11; Figs. 10 to 15 being
drawn to a larger scale than the remaining figs.
Heretofore continuous baking portable ovens have, in practice, invariably been
made mainly of metal. Unsuccessful efforts have been made to utilize tiling in
the construction of the walls, but the loss of heat by radiation, together with the
difficulty of properly distributing the heat to the interior of the oven, have made
them failures.
We believe we are the first to build the walls of an oven of this type of hollow
tiling, utilizing some of the chambers of the walls as smoke flues for carrying the
heat to the parts of the oven so as to properly distribute it, and using the remain-
ing wall chambers as dead air spaces to prevent loss by conduction and radiation.
The advantage of this construction is found largely in the fact that tiling is far
superior to metal in conserving the heat, thereby avoiding fluctuations of tem-
perature due to variations in the intensity of the fire. By the use of the hollow
tiling in the walls we are able to secure at once the advantages of proper dis-
tribution of heat; the conservation of heat, so desirable in such ovens; and the
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page_text: protection against loss by radiation; while avoiding complications in construction
and consequent increased cost.
The oven is provided with a furnace, A, which opens directly into a commodious
flue, D, above which there is located an oven, B, a second oven, C, being added,
if desired. When two baking chambers, B, C, are used the line of draft is traced
as follows: From the flue chamber, D, upwardly through flues, E, at the rearward
end thereof to flue spaces, e, leading forwardly immediately above the oven, B,
to a transverse flue space, e¹, at the forward end of the oven, thence to a vertical
flue, e, and backwardly through flues, e, at the sides of the chambers, B, C, to
vertical flues, et, at the rearward corners of the oven, and again to the forward end
of the oven through flue spaces, e, over the top of the chamber C, and thence
to a chimney flue, e, thereby entirely surrounding the baking chambers with
smoke flues, except at their forward ends. When but a single baking chamber
is used, as shown in Fig. 9, the chimney flue is located at the rearward end of the
oven, and the draft is directly from the side return flues, e³, thereto.
The extreme outer shell, 1, of the oven is preferably of sheet metal, the several
plates being secured together by means of angle-bars, f, and the corners of the
oven being bound by similar angle-bars, g, those at the bottom angles resting,
if desired, upon suitable chairs or feet, f¹. The bottom of the oven is of solid
tiling, G, supported by the angle-bars, g, and by cross Trails, gl. The inner side
walls of the oven are formed of hollow tiles, H, h. The lowest course of these
tiles, h, forms the side walls of the flue chamber, D, which is of the same area in
cross-section, on horizontal plane, as the chamber B, and within which is located
the furnace A. The tiles, h, are oblong rectangular in cross-section, and rest
upon one of their side edges; that is to say; their flue spaces extend horizontally.
These tiles are provided with a vertical partition, h', separating their interiors into
inner and outer chambers, and for the purpose of securing added strength a web, ³,
is thrown across these chambers. The outer face of each of these tiles is prefer-
ably hollowed, the simpler form of construction being to make it concave, as
shown. The upper courses, H, H, of the hollow tiling forming the side walls,
are similar in form to the tiling h, except that along their lower inner angles they
are rabbeted so as to receive the solid tiling, K, forming the floor of the
chamber B and the hollow tiling M, forming the roof of this chamber
and the floor of the chamber C. The tiling K is supported by the tile h, and cross-
bars, k, resting thereupon. The tiling M and similar tiling, M¹, forming the
roof of the chamber are carried by the tiles H, H, and by suitable
cross
beams, m, which are preferably entirely inclosed by the tiles M,, M', the stem
portion of these bars being located between adjacent tiles and the cross portion
fitting within suitable recesses in their adjacent faces, one of the tiles being pro-
vided with a projecting lip, m¹, to cover the cross member of the bar. Like the
tile h, the tiles H have their outer faces hollowed, and the front and rear inner
walls of the oven are built of the same form of tiling, having the same hollowed
outer faces.
Between the outer shell F and the inner walls of the oven there is interposed
a filling, J, consisting preferably of a plurality of sheets of asbestos, this filling
ying against the margins of the outer faces of the tiling, so that a dead air space
is inclosed between each tile and the asbestos.
The rearward wall of the flue space D is formed of tiles, H', of the same style
as the tile h, but standing on end. The inner face of these tiles, however, is broken
out, as shown at h³ in Fig. 7, and elsewhere. The rearward walls of the
chamber B, C, are also made of these tiles, h, standing on end, but without the
mutilation shown in the tile H'. The rearward tile, K, of the floor of the chamber B
rests upon the forwardly extended flanges, h³, of the tile, H', a flue space being
left behind them in register with the forward chamber of the tile h forming the
rear wall of the chamber B. A piece of solid tile or brick, h, is placed upon the
top of the tiling H¹ to support the outer portion of the tile h at the back of the
oven, and a similar piece of brick is placed upon the upper end of these tiles h.

page_text: The tiles M forming the roof of the chamber B are oblong rectangular in form,
and are hollow so as to form the flues, e, these flues extending, as already stated,
from the rear to the front of the oven. The rearward course of the tiles M overlap
the inner chamber of the tiles h, forming the rearward wall of the chamber, and in
order to connect the flues E with the flues e, the lower wall of the tile forming this
course is cut away, as plainly shown in Fig. 1.
The front wall of the oven chamber B consists of a tile, O, identical in form with
the tile H, but overturned, so that its rabbeted portion is across its upper and inner
angle. The forward course of the tiling M terminates in line with the inner face
of the inner wall of the tile O. The front wall of the oven chamber C consists of
tiling, O¹, identical in form with the tiling O, and resting upon the latter. By
this construction it will be seen that the forward cross flue, e¹, is formed, (Figs. 1
and 4) which flue is in communication entirely across the front of the oven with
the flue passages, e.
At each corner of the oven, immediately at the side of the front wall formed
of the tiling O, 0¹, as already described, there is built up upon the lower course, h,
of the inner side walls an L shaped column, P, P, the inner angles of which form
the vertical flue spaces, e, which are open to the cross flue, e¹, and to the return
flues, e, the latter being the inner chamber of the tiling H, forming the side
walls of the oven chambers, B, C, so that the smoke issuing from the cross flue, e¹,
may return through either the upper or lower, or both of the side flues, e³. As the
natural course of the draft will be through the upper of these side flues, and as it
may not always be desired to use the upper oven, we place a simple flat damper, Q,
in the vertical flues, e², controlling the same by means of a rock spindle, q, project-
ing forwardly through the front wall of the oven, and by means of which com-
munication between the cross flue, e³, and the upper return flues, e³, may be
entirely cut off.
The rearward wall of the oven chamber C is formed of tiling, h, like the side
walls of the oven chamber D. A course of solid tile, h4, of the same form as the
similar courses laid across the outer portions, and on top of the rearward walls of
the flue space, D, of the oven chamber, B, is laid across the rearward wall of the
oven chamber C. The roof of the oven chamber C is composed of hollow tile, M¹,
of the same form as the tiling M, the rearward end of this roof resting upon
the inner wall of the tiling, h, so that a cross flue is formed between the rear-
ward end of this roof and the solid tile, h, last referred to, which cross flue is
in connection with the side flues, e, through a vertical corner flue in the same
manner as the vertical flues, e2, at the front of the oven. The flues, e, open to a
similar cross flue at the forward end of the oven, formed by the rabbeted portion
of the tiling O¹, and from this cross flue, e, the chimney flue, e', opens.
The top of the rearward cross flue, e, is covered by a course of ordinary brick, h³,
and the forward cross flue, connecting the flues e³ and e6 is similarly covered.
A layer of filling material, R, either of mineral wool or asbestos, is interposed
between the tile M or M, (when but one of the baking chambers is used,) and the
top of the outer casing, F.
We show at S the furnace door, at T the door of the oven chamber B, and at U
the door of the oven chamber C. There is nothing novel about the two last appur-
tenances of the oven, and we have not deemed it necessary to illustrate or describe
in detail the arrangement of the tiling for the accommodation of the openings to
the oven, inasmuch as the arrangement of these features can be easily provided for
by the artisan who constructs the oven.
It will be seen that as to the flue chamber I, into which the vapors of combus-
tion are discharged from the furnace, we have the advantage of not only very thick
walls, but of triple dead air spaces; and as to the walls through which the flues
pass, there are two dead air spaces outside of the flues, so that the loss of heat by
conduction is very small.
While we have shown the outer casing to be of metal, there is no reason why it
may not be of masonry, if the user prefers.

page_text: The furnace, A, preferably used in connection with the oven, consists of the
grate-bars, a, and the inclosing arch, a¹, of tile. The front ends of the grate-bars
are carried by a chair, 20, resting upon the side walls of the ash-box, their rear-
ward ends being carried by the rearward wall, 22, of the ash-box. The arch, a',
rests upon a pair of angle-bars, 23, the forward ends of which are supported by the
side walls, 21, of the ash-box, and suitable lugs, 24, 25, attached thereto, the outer
lugs, 25, being shown as bolted to the wall 21, to obviate the practical difficulty
of casting, and as having upstanding lugs, 26, to prevent the upward lateral move-
ment of the bars 23, and the consequent spreading of the arch a¹. The arch, a',
is extended backward a suitable distance beyond the grate surface, a, for the
purpose of forming a retort flue, the supporting bars, 23, being prolonged in order
to carry it, their rearward ends being supported by suitable piers, 27. The floor, a²,
of the combustion flue thus formed, is of flat tiling, and supported by the bars 23.
This combustion flue opens directly into the heating chamber, D, of the oven,
and its arch of massive tiling serves to conserve the heat and maintain the neces-
sary high temperature essential to complete combustion of vapors distilled from
the fuel, thereby promoting economy in fuel consumption, and the steadiness of
temperature within the chamber D.
The furnace front is formed with a deep reveal, its frame comprising the side
plates, 28, which have at their inner edges instanding flanges, 29, each provided
with a pair of binge lugs, 30; the top of the frame consists of a similar plate, 31,
having a depending flange, 32, at its rearward edge. The furnace front proper, 33,
fits within the flanges, 29, 32, and is provided with hinge lugs, 34, a pair project-
ing beyond each of its side edges to co-operate with the hinge lugs, 30, with
which they are united by pintles, 35, thus holding the front, 33, securely in place,
but allowing it to be swung upon hinges in either direction by simply removing
the pintles, 35, at one side, or to be entirely removed by first taking out all of the
pintles.
The front plate, 33, is provided with a feed door, 36, for the admission of fuel,
and an ash-pit door, 37, which has a suitable damper, 38, for the admission of air.
A shield or screen door, 39, is hinged across the furnace front in the plane of
the front of the oven, as shown at 40, and this door may be made of sheet metal,
and may be hollow and packed with mineral wool or similar material, and is
provided with a damper, 41, for the admission of air. The office of this outer
screen is to protect the baker from the extreme heat when at his work.
It will be seen that this arrangement of furnace and furnace front provides for
easy access to the interior of the oven for the purpose of repair, it being necessary
only to swing open, or entirely remove the front plate, 33, and then take out the
arch, a¹, and the grate bars, thus providing ample space for entry into the
chamber D.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. In a bake-oven, in combination, a casing having a horizontal partition of
tiling dividing the interior of the casing into two compartments, the upper of
which constitutes a baking chamber; a furnace; a flue opening from the furnace
into the lower chamber, and suitable flues leading therefrom.
2. In a bake-oven, in combination, a casing having a horizontal partition of
tiling forming the floor of the baking chamber and the roof of a heating chamber,
a furnace located within the heating chamber and discharging its vapors of com-
bustion thereinto, and suitable flues leading from such chamber.
3. A bake-oven having its walls formed of hollow tiles arranged so that their
chambers constitute smoke flues.
4. A bake-oven having its walls and baking chamber ceiling formed of hollow
tiles arranged to constitute smoke flues.
5. A bake-oven having its walls and baking chamber ceiling formed of hollow

page_text: tiles arranged so that their chambers form smoke flues leading upwardly at the
back of the oven, forwardly through the baking chamber ceiling, and backwardly
through side walls of the baking chamber..
6. A bake-oven having its walls and baking chamber ceiling formed of hollow
tiles arranged to constitute smoke-flues running through an end, and the sides
and the ceiling of the baking chamber.
7. A bake-oven having its walls formed of hollow tiles having inner and outer
chambers, such tiles being so arranged that the inner chambers of certain of them
constitute smoke-flues, the outer chambers of the tiles forming dead air spaces.
8. A bake-oven having its walls formed of hollow tiles having inner and outer
chambers, their outer faces being concave, such tiles being so arranged that the
inner chambers of certain of them constitute smoke-flues, the outer chambers of the
tiles forming dead air spaces.
9. In a bake-oven, in combination, an outer shell, an inner wall of hollow tiles
having outer and inner chambers, a filling of asbestos or like material between
such casing and wall, a horizontal partition of solid tiles, the chamber below this
partition being a smoke-flue, and the chamber above it being a baking chamber,
the tiles at the rear end of the oven being set so that their inner chambers form
vertical flues opening to the. lower smoke-flue, the tiles forming the side walls of
the baking chamber being arranged so that their inner chambers form horizontal
smoke-flues, a hollow tile ceiling for the baking chamber arrang
to form smoke-
flues leading forwardly from such smoke-flues at the rear end
tion between such ceiling flues and the side wall flues, and/
the last named flues and a chimney flue.
oven, connec-
'tion between
and a heat-
King chamber
the walls of the
10. A bake-oven having two baking chambers, one above/
ing chamber below the lower baking chamber, the floor
being of tiling and forming the ceiling of the heating c
oven being built of hollow tiles having inner and out. chambers, such outer
chambers being dead air spaces and such inner chambers being utilized in part
as dead air spaces and in part as smoke flues, hollow tile ceilings for the two baking
chambers, the chambers of such ceilings being utilized as smoke-flues, the smoke-
flues of the oven leading from the heating chamber upward through the rear wall
of the lower oven, forward through the ceiling thereof, laterally at the front of
the oven, back through the side walls of both baking chambers, inwardly across the
rear end of the oven, forward through the ceiling of the upper baking chamber,
and thence to a chimney flue, and a furnace discharging its smoke into the heating
chamber.
11. The combination with a bake-oven, of an outer casing comprising a frame of
angle-bars to bind the angles of the oven, sheet metal secured to the angle-bars
named, angle-bars for binding the edges of the sheets intermediate of the corners
of the oven, one flange of the last named angle bars projecting inwardly, such
instanding flanges of adjacent bars being secured together.
12. In a bake-oven, the combination with a baking chamber and heating
chamber below and substantially coextensive with the baking chamber, of a furnace
located within the heating chamber and comprising a grate and an arch above the
grate, such arch being prolonged back of the grate to form a combustion flue, and
discharging directly into the heating chamber.
13. In a bake-oven, in combination with a baking chamber and a heating
chamber below the baking chamber, of a furnace within the heating chamber, and
an openable front for such furnace having therein feed and draft openings.
14. In a bake-oven, in combination with a baking chamber and a heating
chamber below the baking chamber, of a furnace within the heating chamber, a
frame in the oven wall for the furnace front, and a front plate, 33, detachably
secured to such frame and having feed and draft openings.
15. In a bake-oven, in combination, a heating chamber, and a furnace located
within such chamber and comprising an ash-box, a grate supported thereby, a
pair of bars supported by the side walls of the ash-box and extending back of such

page_text: box and having an upstanding flange at their outer edges, an arch carried by such
bars, such arch inclosing the grate and extending back thereof to form a com-
bustion flue, and a floor for such flue.
Dated this 19th day of April 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.