IMPROVE- MENTS IN OVENS FOR BAKING OR COOKING
Year: 1882

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN OVENS FOR BAKING OR COOKING." A communication from abroad
by Wilhelm Lorenz, of Vienna, in the Austrian Empire.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 14th February 1882.
16
CHARLES TENTON ABEL of No. 28 Southampton Buildings, Chancery Lane in
the County of Middlesex. IMPROVEMENTS IN OVENS FOR BAKING OR COOKING."
[A communication from abroad by Wilhelm Lorenz, of Vienna, in the Austrian
Empire.]
This Invention relates to an improved construction of baking or cooking ovens
for continuous working whereby, firstly, a very equable and constant temperature
of about 500° Fahr: is maintained by the employment of a large mass of brick-
work, which in taking up the heat from longitudinal and transverse heating flues
formed therein, serves as magazine for a considerable quantity of heat, which is
only slightly affected by variations in the amount of heat supplied theroto or
absorbed therefrom during the operations of baking or cooking. Secondly, the
baking or cooking operation is effected in the presence of steam produced in a
steam generating apparatus of the following arrangement.
A tubular chamber situated between two baking chambers or muffles contains a
shallow tray that is supplied with a regulated quantity of water from a reservoir
on the top of the oven, such reservoir being made for this purpose to communicate
through a very small orifice with a receptacle of a capacity equal to that of the
tray, and communicating with the latter by a pipe with a ball cock, so that no
more water can be supplied at one time to the tray than it can contain. The
front end of the tubular chamber is formed with a head, in which is situated a
safety-valve leading into an escape flue, through which any excess of steam-pressure
in the chamber can escape into the open air. The head has also two side passages
communicating respectively with the two baking muffles, which passages are closed
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page_text: by double valves so arranged that in the one position they open the communication
between the steam chamber and the muffe and close a passage leading from the
latter to the open air, while in the other position they effect the reverse communi-
cations. By this arrangement the baking muffles can either be charged with steam
to the required extent, or this steam can be made to escape into the open air (for
which purpose another passage with regulating valve is provided) and atmospheric
air be made to enter the muffle.
In operating with this apparatus the communication between the baking muffles
and the stean chamber must be opened before the water is admitted to the pan of
the latter, the supply pipe to this being provided with a shut-off cock or valve for
this purpose; the valve leading from the muffle to the escape passage is also
opened for a short time, so as to allow of the escape of the air. When the muffle
has been supplied with steam for a sufficient length of time, the water-supply to
the generator is cut off, the valve of the steam-supply passage is closed and the
passages for the escape of the steam from and for the admission of air to the muffle
are opened. By this means it will be seen the supply of steam to the baking
muffles is under perfect control.
Thirdly. For enabling the baking or cooking operation to be readily controlled
and in order that the articles to be baked or cooked may be easily and rapidly
introduced into or removed from the muffles without requiring skilled labor, the
muffles are provided with a travelling bottom or tray on which the articles are
charged and which runs with wheels upon rails laid on the bed of the muffle. At
the mouth of the latter are corresponding external rails, framed together, and
mounted on rollers on a framing so that when it is desired to gain access to the
mouth of the muffle the rails can be run back somewhat, and when the travelling
bottom requires to be introduced into or removed from the muffle the rails are
run up against the mouth of the latter, the rails being held securely in either
Josition by bent arms thereon that hook underneath the framing.
Fourthly. For enabling the temperature of the baking muffles to be constantly
watched, the mouths thereof (the doors of which are made to slide up and down
in guides) are provided with thermometers having a vertical external limb and a
liorizontal limb extending through the door framing into the muffle so as to be
subject to the heat thereof.
Fifth. For enabling the action of the heating furnace to be maintained with
regularity independently of the fireman and for distributing the flames and hot
gases uniformly throughout the heating flues, the heating apparatus, when solid
fuel is used, is arranged as follows. A vertical shaft or chamber is provided at
bottom with a grate and at top with a charging opening closed hermetically by a
hood, with sand luting, and also with eyeholes for observing the combustion. The
ash-pit below the grate and an opening in the front wall above the latter are
closed by a plate hinged at bottom and capable of being opened to a regulated
extent at top so as to admit the required quantity of air for effecting the combustion.
The firebridge is made of some depth so as to contain a comparatively large body
of fuel above the grate for which purpose slack or small coal is used this being
charged in large quantities at a time through the top charging opening. The fuel
is lit at the top and is allowed to burn gradually downwards until the charge is
consumed, when the dust and clinkers are removed and a fresh charge is introduced
and lit.
For facilitating the removal of the dust and clinkers, the ashpit door is taken
away, and a transverse bearer which supports the front ends of the furnace bars,
is drawn from under these by means of a chain, whereupon the grate bars turn
down upon hinges at the back end, so that they can be readily cleared of all
clinkers.
The flames and hot gases after passing over the firebridge issue into a wide
flue running parallel with the baking muffles, into which flue open a number of
small transverse flues formed in the brickwork surrounding the muffles, and which
communicate with the chimney. By causing the furnace gases to issue first into

page_text: the wide longitudinal flue the greater part of the dust carried with them is
deposited therein and is not carried into the small transverse flues. These, as also
the longitudinal flues are extended through the brickwork at one end where they
are closed by doors or stoppers, so that on removing these from time to time the
collected dust can be readily cleared out; dust collecting chambers or pockets are
also provided at intermediate points in the length of the Blues. The transverse
flues are made to gradually diminish in sectional area from the furnace end to the
chimney end; they traverse the brickwork in zig-zag direction so as to offer very
extended surfaces for taking up the heat from the gases and imparting it to the
brick work.
In order to ensure that there shall be an equal draught through all the flues,
notwithstanding their different distances from the furnaces (of which there are by
preference two provided) the chamber into which they issue before escaping into
the chimney is provided with suitably shaped baffle walls so as restrict the
entrance of the gases from some of the flues more than from others. The said
chamber is also provided with stoppered openings for clearing out the deposit, and
it has a hood-shaped valve closed with sand luting, by means of which the flues
and furnace can be cut-off from the communication with the chimney, this being
effected when the flues and chamber require clearing or for other purposes. Closed
air spaces are formed in the external parts of the brickwork to prevent loss of heat
by radiation.
For heating by means of gaseous fuel, the arrangement of the flues is the same.
as above described, with the exception that no dust collecting flues or pockets are
required, and that air supply flues are provided through which the air required
for combustion with the gas is made to pass so as to become heated to a certain
degree. The combustible gas employed for this purpose is by preference water
gas, which is led in a cold condition from a gas holder through a pipe to the
burners situated together with the gas pipe in a large air flue or chamber which,
when the oven is in operation only communicates with the outer air through the
before mentioned hot air flues, but which at other times is accessible to workinen
for the inspection and repairing of the burners.
The burners consist of nozzles formed as branches on the supply pipe, the upper
end of the nozzle being covered with a hood having openings for the inlet of air
at the bottom while at top a narrow annular space is formed between the top of
the gas nozzle and the hood so as to allow of only the correct proportion of air
combining with the gas. The hood has a necklike tubular extension abutting
against a tapering passage formed through the brickwork into one of the before.
described flues, into which consequently the mixture of air and gas issues, and
where it is ignited, there being one such burner provided to each of the said flues,
which have stoppered openings through which the ignition can be effected and eye
holes through which the state of combustion can be observed.
The main gas
supply pipe, as also the separate burners are provided with cocks or valves for
regulating the gas supply.
The heating apparatus whether for solid or gaseous fuel is quite separate from
the locality where the baking operation is carried on and is operated by separate
attendants, so that no interruption of the baking or cooking operation is caused
thereby.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Great Seal Patent Office on the
1st August 1882.
CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in
the County of Middlesex. "IMPROVEMENTS IN OVENS FOR BAKING OR COOKING."
A communication from abroad by Wilhelm Lorenz of Vienna, in the Austrian
Empire.
This Invention relates to an improved construction of baking or cooking ovens
for continuous working whereby Firstly, a very equable and constant tempe-
rature of about 500° Fahr. is maintained by the employment of a large inass of
brickwork which in taking up the heat from longitudinal and transverse heating
flues formed therein serves as magazine for a considerable quantity of heat which
is only slightly affected by variations in the amount of heat supplied thereto or
absorbed therefrom during the operation of baking or cooking. Secondly. The
baking or cooking operation is effected in the presence of steam produced in a
steam generating apparatus of the hereinafter described arrangement, whereby
steam can be rapidly generated and admitted to the ovens, and also be discharged
therefrom.
Thirdly. For enabling the baking or cooking operation to be readily controlled
and in order that the articles to be baked or cooked may be easily and rapidly
introduced into or removed from the muffles without requiring skilled labour, the
muffles are provided with a travelling bottom or carriage on which the articles
are charged and which runs with wheels upon rails laid on the bed of the
muffle.
Fourthly. For enabling the temperature of the baking muffles to be constantly
watched, the mouths thereof are provided with thermometers having a vertical
external limb and a horizontal limb extending through the door framing into the
muffle so as to be subject to the heat thereof.
Fifthly. For enabling the action of the heating furnace to be maintained with
regularity independently of the fireman, and for distributing the flames and hot
gases uniformly throughout the heating flues the heating apparatus is arranged
as heroinafter described operating either with solid fuel, of which a large quantity
is charged at a time and allowed to burn out, or with gaseous fuel.
Sixthly. The heating apparatus whether for solid or gaseous fuel is quite
separate from the locality where the baking operation is carried on and is operated
by separate attendants, so that no interruption of the baking or cooking operation
is caused thereby.
DESCRIPTION OF THE DRAWINGS.

page_text: apparatus, Fig 11 shewing a longitudinal section on line K L Fig 3; Fig 12 a
cross section on line L M Fig 13; Fig 13 a cross section on line M N Fig 11;
Fig 14 a cross section on line NO Fig 13; Fig 15 a front view of the plate
closing the lower part of the apparatus shewn in Fig 14; Fig 16 shews a longitu-
dinal section through the fire grate of the arrangement for solid fuel and Fig 17 a
cross section of the same on line P Q Fig 16; Fig 18 shews a longitudinal section
of the arrangement through the combustion apparatus for gaseous fuel, and cross
section of the gas pipe.
The brickwork structure contains two muffles A A serving as baking chambers
the roof being supported on T iron bearers between which bricks are laid. The
floor is provided with rails on which runs the carriage B. The front openings of
the muffles are closed by doors sliding vertically in frames C and balanced by
weights a. The frame C contains in a recess in its upper part an elbow thermometer
D for indicating the temperature of the oven, the horizontal limb of which reaches
into the oven, while the external vertical limb is provided with a scale. The rails
of the ovens have external extensions resting on rollers on a framing. E so that they
can be moved away from the oven to allow of access thereto, and pushed close up
in order to allow the baking carriage to be moved into or out of the oven. The
said rails are framed together by means of cross pieces, and they are provided with
horns b which embrace the rollers of E in the end positions and thus prevent them
from canting. The baking carriage consists of a tray fixed on an angle iron framing
carried by four wheels, and serves to receive the articles to be baked and to convey
the whole of them simultaneously into and out of the oven, thus affording an easy
manipulation thereof. In a space between the two baking muffles is situated the
steam generating apparatus F shewn at Figs. 11 to 15, for producing the steam or
vapour required in the ovens during the process of baking. The apparatus consists
of a cast iron tube c in which is a copper pan d for containing the water to be
converted into steam. This water is supplied from a reservoir Z on top of the oven,
in which a constant water level is maintained by a ball cock. In order that no
excess of water may be supplied to the pan d a sinal receptacle e is formed on the
reservoir, which contains as much water as the pan d can hold, and which communi-
cates with the reservoir only through a small opening, so that it will take considerable
time to charge the receptacle e. The steam apparatus communicates with the
receptacle e through a pipe f having a shut off valve attached to the front cover of
the tube c, this tube has a separate front-end, closed by the said cover, and having
a safety valve g which prevents excessive steam pressure in the tube, and through
which the steam issues into the passage h and thence into the open air. The front
end of the tube c also has two steam valves ii through which the steam can be
admitted into the one or other baking muffle through the passages . They are
double seated valves so that according to their position they close the one or other
of the two opposite openings and m, of which connects the tube c with the
muffle while m connects the latter with the outer air, so as to admit at will either
steam or atmospheric air into the muffle. The front-end of the tube c also has in
its upper part the two-steam valves o o through which the steam from the muffles
can escape into the open air, in which case atinospheric air enters the muffles through
the opening m of the valve i. These valves are operated in such a manner that
when the muffle is to be charged with steam, the aperture & connecting the muffle
with the tube c is first opened before the pan d is charged with water. The steam
produced then enters the muffle, expelling the air therefrom through the valve o
which is opened only for a very short time, and through the passages h into the
open air. If after a certain time the aperture 7 be closed, after the valve of pipe f
has been shut off on the pan & being filled, and the valve o be opened, the steam
will rapidly escape from the muffle through this valve, air entering it at the same
time through the opening m of the valve i. By this means the muffle can be easily
and rapidly filled with or freed from steam.
When the oven is in operation it must only receive as much heat as is taken up
by the articles to be baked and as is lost in the escaping gaseous products of

page_text: combustion, and by radiation from the outer walls, so that only a comparatively
small area of grate surface is required. The heating apparatus, which is only
accessible from the firing chamber, having no direct connection with the baking
room, consists of the combustion chambers g having below fire grates p P P and
closed above by a fire brick arch in which are formed the charging openings H
closed by bell covers, and the sight holes J. The front ash pit openings are closed
by plates q; rrr are the five bridges, from which extend the flues KK terminating
in the smoke chamber L leading to the chimney. The combustion chamber is
arranged for burning small coal or slack which is introduced periodically in such
large quantities that the combustion will continue for several hours without fresh
supply. The fuel is ignited at top and burns downwards, the rate of combustion
being controlled by regulating the inlet of air through the plates q. The fuel
having burnt out, the grate is carefully cleared, and provided with a fresh supply
of fuel. For clearing the grate, the plate q is removed, and a bearing plate t, which
supports the front ends of the bars p is drawn from under these by means of a
chains; the plate trests on arms u pivotted to the bars (which are framed together
so as to form one piece) and resting on lugs v on the ash pit framing so that when t
is withdrawn from between the ends of the bars p and the arms u, the bars drop
down turning on their rear hinge x into a nearly vertical position in which they
can be readily cleared. The grate bars are then again raised and supported by the
insertion of the plate t. Immediately behind the bridge r is a large passage M
serving to distribute the hot products of combustion passing from the three grates
to the several flues K K, and also to intercept a large portion of the ashes or dust
carried along with the gases, thus keeping the flues K comparatively clear, and
therefore performing a very important function. Other dust pockets N and O are
also provided at those points of the flues where a change of direction takes place.
The ashes can be removed through openings P closed with covers.
Figs 1 to 8 shew the arrangement of the several flues K starting from the
passage M and terminating in the smoke chamber L; they are of equal width, but
of variable height, decreasing from the ends at M towards the ends at L. They
are led backwards and forwards in the brickwork so as to afford such an extent of
surface as will effectually absorb a large portion of the heat from the gases and
impart it to the mass of brickwork. These flues K K are accessible for cleansing
through openings QQ closed by covers. In order that there may be an equal
draught through all the flues K it is necessary that they should all be of equal
length from the passage M to the chimney; this is effected by constructing the
smoke chamber, where they enter it, as shewn at Fig. 3. Situated in the sinoke
chamber is a bell valve having a sand lute and capable of being raised and
lowered by levers, and serving to separate the chimney from the combustion
chambers when these require to be cleaned, or when other operations have to be
performed whereby a large quantity of cold air would otherwise enter and pass
through the flues. The valve R does not serve to regulate the heat imparted to
the oven this being solely effected by regulating the quantity of air passing through
the fire grates, for which purpose the plate q is held more or less open by the
adjustment shewn at w. The proper draught is insured by a chimney of suitable
size discharging the products of combustion into the open air, as before stated.
X X are air spaces in the brickwork for preventing loss of heat by radiation.
For heating by gaseous fuel the arrangement of flues and smoke chamber is the
same as described, Figs 5 to 8 shew the apparatus for this purpose. The only
difference is that the dust pockets are dispensed with, not being required, and
that the flues before entering the smoke chamber pass in close contiguity to air
flues S S, through which the air required for combustion flows, so as to become
heated and effect a more perfect combustion with the gas at the burners W. This
mode of heating is simpler than that with solid fuel, inasmuch as the work of
supervision is much less, and there is no clearing of the passages required, in
addition to which the temperature can be regulated with greater precision. The
burners are fed with water gas from a gasholder through a pipe T with the main

page_text: shut off valve V for regulating the supply. The pipe T has seven branches B B to
which are fixed the burners W, it is situated in a passage U large enough for the
attendant to pass through but which, when in operation is only in communication
with the outer air through the flues S. Each burner has a separate stop cock 8,
they are so constructed that the proportion between the orifices x for gas and
those for the necessary supply of air shall always be the same, and they
consist of a tube n for conducting the gas to the orifice x covered by a hood a
having at top a tubular extension through which the mixture of gas and air
issues into the tapering passage s leading into the flues K. while the air for com-
bustion enters through openings in the lower part of the hood. The annular
space between the top of the nozzle a and the top of the hood is such as to
supply the exact quantity of air to the gas required for complete combustion, which
is effected as the mixture of gas and air issues into the flue K from the passage 5.
For igniting the jets, end openings are provided leading into the flues K, as shewn
at Fig 5 and closed by covers y, which are provided with sight holes for observing
the state of combustion. The other parts of the oven are of the same construction
as first described.
Having thus described the nature of this Invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent,
I claim-
First. The general construction and arrangements of combustion chambers flues
and apparatus for heating ovens whether by means of solid fuel or by gaseous
fuel, substanially as herein described.
"
Second. The herein described construction and arrangement of apparatus for
producing steam for the supply of ovens therewith.
Third. The herein described construction of the baking chambers or muffles with
baking carriage and rails therefore and external framing for the reception of the
carriage.
In witness whereof 1 the said Charles Denton Abel have hereunto set my
hand and seal this Twenty fourth day of July in the year of our Lord
One thousand eight hundred and eighty two.
DET
CITAS D. ABEL.
(U.S.)