An Improved Portable Baking Oven for Domestic and other Use.
Year: 1885

page_text: An Improved Portable Baking Oven for Domestic and other Use.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention for "AN IMPROVED
PORTABLE BAKING OVEN FOR DOMESTIC AND OTHER USE" a communication to me
from abroad by Armand Chappée of le Mans in the Department of Sarthe, France,
Engineer, to be as follows:-
=:
This Invention relates to a portable baking and cooking oven applicable also for
other purposes, and it has for its object to provide an improved oven for domestic
use for baking bread and other food in an economical manner. By this means the
use of baker's bread made with flour usually containing a large admixture of other
matters having inferior nutritive qualities may be avoided, and home made bread
may be brought within the reach of any one possessing one of these ovens.
These ovens are of inexpensive construction and may be made of any size,
according to particular requirements..
Reference is to be had to the accompanying drawings and to the letters and
figures marked thereon, wherein I have represented an example of a portable
oven for domestic use. Figure 1 is a half sectional front elevation; Figure 2 a
longitudinal vertical section, and Figure 3 a sectional half plan of the oven.
The apparatus consists of a furnace with charging, door, fire bars, and ash pan.
This furnace is constructed to consume any kind of fuel, such as wood, coal, peat, etc,
and is corrugated or fluted internally to avoid cracks produced by sudden cooling..
Within the furnace chamber is placed the oven constructed of a corrugated or
fluted bottom plate A and a dome B also corrugated or fluted and provided with a
mouth or opening closed by a door, which latter parts may be corrugated or fluted
internally or externally. The corrugation or fluting of these various surfaces serves
in all cases, not only to prevent breakage by sudden cooling, but also to increase
the heating surface and consequently the temperature of the oven by increasing its
internal surface. The dome B rests on the bottom A which is itself supported
above the fire by four brackets C projecting inward from as many ribs or

page_text: corrugations on the sides of the fire place. The bottom A is strengthened by cross
ribs D at the underside and supports by means of ribs on the upper surface, an
upper or false bottom E upon which are laid the bricks forming the hearth of the
oven. A space or hot air chamber F is thus left between the bottom A and the
false bottom E, the edges of which only meet the apexes of the internal ribs or
corrugations of the dome, thus leaving channels all round the hearth by which the
hot air contained in the hot air chamber F comprised between the plates A and E
can escape and rise into the interior or baking space of the oven. In order to
prevent the entry of smoke into the interior of the oven, the lower edge of the
dome B fits within a rising flange or rim around the bottom A so as to make a
joint. The dome B is furnished with a handle or ring I for lifting it in and out of
its place in the oven. The dome B is enclosed by an outer dome G also fluted or
corrugated internally and fits on and makes a tight joint with the lower part of
the furnace chamber. This outer dome has for its object to cause the flames and
gases from the furnace to play against the inner dome B of the oven proper and
thus to utilise to the utmost the heat of the fire. The dome G is connected to a
chimney for carrying off the products of combustion and furnished with a damper
for regulating the draft. At the base of this chimney there is a downwardly pro-
jecting circular rib or flange H which by narrowing the space between the inner
and outer domes, retards the exit of the gases and brings them into close contact
with the oven.
The whole oven is mounted upon cast iron legs or feet so as to bring the mouth
of the oven to a convenient height.

page_text: An Improved Portable Baking Oven for Domestic and other Use.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this Invention (a communication to me
from abroad by Armand Chappée of le Mans in the Department of Sarthe France
Engineer, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This Invention relates to a portable baking and cooking oven applicable also for
other purposes and it has for its object to provide an improved oven for domestic
use for baking bread and other food in an economical manner. By this means
the use of baker's bread made with flour usually containing a large admixture of
other matters having inferior nutritive qualities may be avoided and home made
bread may be brought within the reach of any one possessing one of these ovens.
These ovens are of inexpensive construction and may be made of any size according
to requirements.
In order that the Invention may be more readily understood I will proceed to
describe it with reference to the accompanying drawings wherein I have represented
an example of a portable oven for domestic use.
Figure 1 is a vertical section of the oven complete. Figure 2 is a plan and
Figure 3 a half sectional front view of the furnace. Figure 4 is a plan of the
dome or cover. Figure 5 is a front view of the charging door drawn on a larger
scale and Figure 6 a part sectional plan of the same. Figure 7 is a section taken
on the line A B of Figure 6. The same letters of reference represent like parts in
all the Figures.
The apparatus consists of a furnace with charging door or doors fire bars and ash
pan The furnace is constructed to consume any kind of fuel such as wood, coal,
peat, etc and is fluted or corrugated internally to avoid cracks produced by sudden
cooling. Within the furnace chamber is placed the oven constructed of a corrugated
or fluted bottom plate i and a dome or cover e also corrugated or fluted and
provided with one or more mouths or openings closed by a door or doors q which
latter parts may also be corrugated or fluted internally or externally. The
corrugations or flutings of these various surfaces serves in all cases not only to
prevent breakage by sudden cooling but also to increase the heating surface and
consequently the temperature of the oven by increasing its internal surface.
dome or cover e rests upon the bottom plate i which is itself supported above the
fire in any suitable manner. The bottom i is provided with brackets upon which is
supported an upper or false bottom to carry the hearth which may either be made
of bricks or preferably of perforated sheet iron galvanized. The false bottom f
upon which the sheet metal hearth is placed is provided with raised edges g to
prevent the ends of the loaves from becoming burnt by approaching too close to the
sides of the furnace chamber; while it also moderates the heat radiated from the
The

page_text: the oven.
bottom with which the flames are in direct contact. The edges g of the false
bottom do not touch the sides of the furnace chamber e but only meet the apices
of the internal ribs or corrugations of the same thus leaving channels all round the
hearth by which the hot air contained in the chamber comprised between the
bottom and false bottom f can escape and rise into the interior or baking space of
the oven In order to prevent the entry of smoke into the interior of the oven the
lower edge of the dome or cover e fits within a rising flange or rim around the
bottom i so as to make a joint one with the other: The dome e is furnished with
handles or rings for lifting it in and out of its place in the oven and it is enclosed
by an outer dome d supported above the furnace casing n also fluted or corrugated
internally. The object of this outer dome is to cause the flame and gases from the
furnace to play against the inner dome e of the oven and thus utilize to the full
extent the heat of the fire. The dome d is surmounted by a chimney b for carrying
off the products of combustion and furnished with a damper for regulating the
draught. At the base of this chimney within the dome there is a downwardly
projecting circular flange which, by narrowing the space between the inner and
outer domes, retards the exit of the gases and brings them into close contact with
The fire box p with its ash pan m is placed at the front part of the
oven in order to have the same temperature throughout. The size of the grate k
and distance between it and the corrugated bottom i are so regulated as to obtain
the same results whether wood, coal, or coke, be employed as the heating agent.
The interior of the furnace in contact with the fuel is lined with corrugated plates
'which may be replaced at but a small expense without taking the oven to pieces.
c door at which the soot' can be readily cleared out for the purpose of ensuring a
free outlet for the smoke. In large ovens in which a number of loaves are baked
at a time the steam necessary for imparting a gold color to the crust is produced by
the evaporation of the water contained in the dough. In portable ovens however
it is necessary to produce this steam artificially which may be done by means of
any suitable apparatus but preferably by the employment of a vessel a (see
Figure 1) provided with a cock and iron pipe z for discharging water upon the
corrugated plate i After the oven is charged the cock is turned on to admit the
water contained in vessel a into the furnace where it is immediately vaporized
the vapor rising to the upper part of the oven and becoming condensed upon the
surface of the dough while the latter is still cold. The steam produced in this
manner also prevents the crust becoming too hard. The oven should be kept closed
for twenty minutes after being charged in order that the steam may have its due
effect and for this reason also the door should be perfectly steam tight.
Figures 5. 6. and 7. show an oven door which can be hermetically closed even
although the hinges are badly made or may work loose through.wear.
The door q
is suspended by bolts & upon a bar w uniting the two branches of a hinge hung
The bar wis
upon a hinge-pin t mounted in knuckles on the mouth of the oven.
provided at its opposite end with a handle x which, owing to its being separated
from the door never gets too hot and it is fixed by engaging in the rack u.
Between the door q and lever wand upon the bolts 8 are placed spiral springs y
which adjust themselves to the position of the hinges and thus always ensure a
perfectly tight closure of the door Another advantage of these springs is that in
the event of too much water being introduced into the oven when it is tightly
closed which might cause considerable pressure of steam the steam would force the
door outwards by compressing the springs and thus allow the steam to escape.
pis a pyrometer graduated from forty degrees to three hundred degrees which
projects down within the oven so as to accurately indicate the heat in its interior,
the upper portion of the tube being protected by a metal casing. A red line upon
the pyrometer indicates the maximum temperature which should be employed in
baking. The oven is supported upon four legs which ensures the necessary
stability. The apparatus of this Invention may also, by suitably modifying the
accessory parts, be employed as a heating stove or calcining furnace or otherwise.

page_text: Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is;-
1st The herein described construction of portable oven for domestic use for
baking bread and other alimentary products and applicable for other purposes as
specified.
2nd The combination with an oven for baking and other purposes as herein
described, of a water vessel provided with a pipe for discharging water upon the
corrugated bottom plate i of the oven for the purpose of producing steam in the
interior; a pyrometer for indicating the internal temperature, and a steam tight
door provided with springs which allow of its opening should the pressure exceed
a certain limit, all as herein before described and illustrated in the drawings.
D