IMPROVEMENTS IN PORTABLE OVENS FOR BAKING BREAD AND OTHER ALIMENTS
Year: 1881

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
PORTABLE OVENS FOR BAKING BREAD AND OTHER ALIMENTS." A communi-
cation from abroad by Messieurs Geneste Herscher and Company of Paris
in the Republic of France Engineers.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 29th December 1881.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman. "IMPROVEMENTS IN PORTABLE OVENS FOR BAKING BREAD AND
OTHER ALIMENTS." A communication from abroad by Messieurs Geneste
Herscher and Company of Paris in the Republic of France Engineers.
This Invention relates to portable ovens for baking bread and other aliments
and it consists in constructing these ovens in sections as hereinafter described
whereby they are rendered capable of being transported to localities inaccessible to
wheeled vehicles and the operations of erecting them and taking them to pieces are
also greatly expedited and facilitated.
The ovens usually employed for baking bread for the use of armies during a
campaign are either complete ovens fixed upon a vehicle or carriage or are capable
of being taken to pieces and divided into a number of small packages which may
be transported upon very light vehicles or upon the backs of mules. The ovens
belonging to this latter class as heretofore constructed consist generally of a frame
or shell of metal made in sections and employed to form the chamber or vault of
the oven the solid part of the walls of the oven being composed of earth.
It is evident that to put these ovens in order for working a loss of time is
incurred firstly in putting the shell or frame work together secondly in placing the
earth in position and thirdly in drying this earth and heating it to the temperature
necessary for baking bread. Similar disadvantages also attend the operation of
taking down the oven in order to remove it.

page_text: Now in the apparatus constructed according to this Invention all these disad-
vantages are removed :-
The improved oven is constructed with a series of bays or arched sections which
simply require to be arranged in juxtaposition side by side in order to form a
complete oven ready for immediate use.
In carrying out this Invention the improved portable oven is composed of a
number of sections corresponding to the shape of the oven and constructed with
steel plates stiffened by iron stays bolted to a truss of the same material.
These sections are in the form of an arch or bay the weight and dimensions of
which are so calculated as to enable them to be manipulated with facility and
carried on the backs of mules.
On the convex side of the arch of steel plates there is placed a layer of cement
or plastic material capable of resisting the action of heat and also capable of storing
This
up the quantity of caloric requisite for the process of baking the bread.
cement is covered with a layer of suitable non conducting material in order to
prevent loss of heat by radiation and the whole is enclosed by a sheet iron
envelope.
An arch or bay thus constructed constitutes a section of the sides and roof of the
oven which may be built up with any convenient number of such bays or arches
arranged side by side and drawn together by chains the latter being connected to
These
screws passed through cars or lugs on end walls hereinafter described.
'chains are tightened by turning suitable nuts bearing against the said ears or lugs.
The two extremities of the oven are closed by straight vertical walls constructed
in a similar manner to the arched sections hereinbefore described being provided
internally with layers of fire proof and nonconducting materials. The door of the
oven is formed in one of these end walls and the other end wall is provided with a
chimney or flue controlled by a damper.
The-oven-may-be-provided-with-a-bottom-or-floor-consisting of earthenware
panels or tiles supported in a metal frame or frames but in certain cases this bottom
may be dispensed with by a suitable preparation of the ground upon which the
oven is erected.
The tiles of the floor are bound together by a fire proof cement and metal slips
or partitions partially imbedded in the floor serve to support the shovels used in
working the oven and thus protect the tiles from injury. Each panel or frame of
which the floor is composed may correspond in size to one bay or to half a bay and
the weight of the panels is so calculated as to admit of their being carried on the
backs of mules. The improved oven may be fitted together and worked upon a
vehicle when the nature of the ground will admit of such an arrangement.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
28th June 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman. "IMPROVEMENTS IN PORTABLE OVENS FOR BARING BREAD AND
OTHER ALIMENTS." A communication from abroad by Messieurs Geneste,
Herscher and Company of Paris in the Republic of France Engineers.
This Invention relates to portable ovens for baking bread and other aliments and
it consists in constructing these ovens completely from sections formed as herein-
after described whereby they are rendered capable of being transported to localities
inaccessible to wheeled vehicles and the operations of erecting them and taking
them to pieces are also greatly expedited and facilitated.
The ovens usually employed for baking bread for the use of armies during a
campaign are either complete ovens permanently fixed upon a vehicle or carriage
or are capable of being taken to pieces and divided into a number of small packages
which may be transported upon very light vehicles or upon the backs of mules.
The ovens belonging to this latter class as heretofore constructed consist generally
of a frame or shell of metal made in separable sections and employed to form the
chamber or vault of the oven the solid part of the walls of the oven being com-
posed of earth.
Ovens of this description consist simply of means for more or less
expeditiously constructing an oven with common earth.
It is evident that to put these ovens in order for working a loss of time is
incurred firstly in putting the shell or framework together, secondly in placing the
earth in position and thirdly in drying this earth and heating it to the temperature
necessary for baking bread. Similar disadvantages also attend the operation of
taking down the oven in order to remove it.
Now in the ovens constructed according to this Invention all these disadvantages
are removed. The improved oven is constructed with a series of bays or arched
sections which simply require to be arranged in juxtaposition side by side in order
to form a complete oven ready for immediate use. In other words the improved
oven is not composed as are the ovens ordinarily employed of sections of the
internal part or framing only but is built up with sections of the oven itself so
that it is simply necessary to put the parts together in order to obtain an oven in
working order.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents one of the bays arches or
sections of the improved oven partly in elevation and partly in section.
Figure 2 is a corresponding longitudinal vertical section and
Figure 3 is a plan partly in section.
Figure 4 is a general view of a combination of the improved sections arranged
for an oven capable of baking say 90 rations.
In carrying out this Invention the sections of the improved oven are constructed
with an arch A preferably of sheet steel stiffened by stays B preferably of iron
bolted to a truss C of the same material. These sections are in the form of an
arch or bay the weight and dimensions of which are so calculated as to correspond
with a given quantity of bread and to enable them to be manipulated with facility
and carried on the backs of mules.

page_text: The arch illustrated in the Drawing is adapted to contain eight regulation loaves
each weighing about 3lbs. and the weight of the arch itself need not exceed 20lbs.
On the outer side of the arch of steel plates A there is placed a layer of cement
or plastic material a capable of resisting the action of heat and also capable of
storing up the quantity of caloric requisite for the process of baking the bread.
This cement is covered with a layer of suitable non conducting material b in order
to prevent loss of heat by radiation and the whole is enclosed by an envelope D
preferably of sheet iron.
An arch or bay thus constructed constitutes a section of the sides and roof of
the oven which may be built up with any convenient number of such bays or
arches.
The bays are arranged side by side and drawn together by chains c c¹ connected
to screws passed through ears or lugs on end walls hereinafter described as shown
in the Drawing Figure 4. These chains are tightened by turning suitable nuts c²
bearing against the said ears or lugs.
The two extremities of the oven are closed by straight vertical end walls F F¹
constructed in a similar manner to the arched sections herein before described being
provided internally with layers of fire proof and nonconducting materials. One of
these end walls presents a suitable mouth or opening G for working the oven and
the other end wall is provided with a chimney or flue H controlled by a
damper.
The oven may be provided with a bottom or floor consisting of earthenware
panels or tiles supported in a metal frame or frames but in certain cases this bottom
may be dispensed with by a suitable preparation of the ground upon which the
oven is erected. The tiles of the floor (where such are used) are bound together by
a fireproof cement and metal slips or ridges partially imbedded in the floor serve
to support the shovels or peels used in working the oven and thus protect-the-tiles-
from injury. Each-panel or frame of which the floor is composed may correspond
in size to one bay or to half a bay and the weight of the panels is so calculated as
to admit of their being carried on the backs of mules. The improved oven may be
fitted together and worked upon a vehicle when the nature of the ground will
admit of such an arrangement.
Figure 5 shows diagrams of the sections arranged in different numbers to form
ovens of various sizes.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
Constructing portable ovens in relatively small and light sections which simply
require to be arranged side by side in order to form a complete oven ready for
immediate use and adapted for baking bread or other aliments substantially as
herein before described and illustrated in the accompanying Drawings.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this Twenty seventh day of June One
thousand eight hundred and eighty two.