IMPROVEMENTS IN THE ARRANGEMENTS AND CONSTRUCTION OF OVENS
Year: 1864

page_text: LETTERS PATENT to Frederick Smith, of York Street, York Road,
Lambeth, in the County of Surrey, Builder and Oven Builder, for the
Invention of "IMPROVEMENTS IN THE ARRANGEMENTS AND CONSTRUCTION OF
OVENS."
Sealed the 30th August 1864, and dated the 4th March 1864.
PROVISIONAL SPECIFICATION left by the said Frederick Smith at the
Office of the Commissioners of Patents, with his Petition. on the
4th March 1864.
I, FREDERICK SMITH, of York Street, York Road, Lambeth, in the County
of Surrey, Builder and Oven Builder, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE ARRANGEMENTS AND CONSTRUCTION OF OVENS,"
to be as follows:-
In carrying out my improvements I propose to construct a chamber or oven,
say, for example, eleven feet from side to side, and eight feet from front to
back, inside measurement; this of course may be varied according to require-
ments, as also the brickwork round same, which would vary from one and a
half to three bricks in thickness. The bottom of the oven I support on T-iron
girders resting on piers of brickwork, from each of which would be stretched
a fire-tile covering the space between the girders, the under part of the tiles

page_text: forms the upper surface of the flues under the oven (or a series of flat arches
might be substituted), and on this again is bedded the ordinary red oven tile
as the sole of the oven. In places where an inferior description of fuel is used
I cover over the flue spaces with iron plates instead of fire-tile, and on them
put ordinary oven tiles. The top of the oven is also supported with T-iron
girders, or girders made as a cross, thus +, so that a portion might descend
into the oven at top, which would tend to prevent the rapid passage of heat,
steam, and gaseous products. The height of the crown or top of the oven
from the bottom or floor would depend upon the description of goods to be
baked, but would range between fourteen and twenty-four inches. Under
the bottom and over the top are placed soot doors, so as to enable the flues to
be cleaned out at any time; or if this plan should in some cases be found
inconvenient an arrangement could be made for lifting some of the fire-tiles
in the bottom leading to the flues, and a similar arrangement could be adopted
outside at top of the oven to command flues in a like manner by taking up a
stone or tile with which the oven is paved at top. On the top of the oven tho
flue space is partitioned so as to form flues to and fro over the top of the oven,
which space should be about seven inches from bottom to the covering of the
flue. The flue space below the oven is similarly partitioned, and would be
about nine inches in depth to allow for the depth of the girder descending
therein. On the girders that support the top of the oven I place fire-tiles or
flat arches, properly bedded and flushed, on girders before mentioned; and for
more effectually keeping in the steam and heat of the oven I propose to place
a series of sheets of wrought iron rivetted together and firmly bedded on the
top of the fire-tiles and girders before mentioned. In cases where greater
economy is required, instead of the plate iron as aforesaid, I use and bed plain
tiles. On the top of the plate iron I build brickwork half a brick thick to
form the flue partitions, and on this are thrown across either fire-tile or stone
coverings, or iron might be used; this is then filled in with sand or other
material to the thickness of about two feet six inches, more or less, according
to circumstances, for the purpose of retaining the heat of the oven. The flue
passage thus passes from the furnace over the top of the oven in a serpentine
or zig-zag course down a channel in the brickwork at the side of the oven
and then in a serpentine course under the oven; the flue thence passes down
a channel in the front brickwork of the oven close by the oven, in which works
a damper; this flue is connected to an ordinary chimney in the usual manner.
This damper and a ventilator in the ash-pit door commands the draught,
and consequently regulates the heat of the oven. The hot air or smoke in
describing a serpentine or to-and-fro course above, as well understood, the

page_text: heat is more readily and perfectly absorbed than by any other arrangement
heretofore adopted in ovens. The heat is obtained from a furnace the fire-
bars of which would be, say, twenty-four inches in length, more or less,
according to the size of the oven, with a dead plate about nine inches wide in
front of same to lessen the radiation of heat into the bakehouse. This furnace
is placed either at the right or left hand side of the oven, the door of which
stands inwards eight inches, more or less, according to size, from the line of
oven front. By the side of the furnace, and next to the oven, is placed an
iron plate, near the wall or side of the furnace, in a position inclined thereto,
so that the space narrows towards the top, which plate is level with the bottom
and near the commencement of the upper system of flues. The bottom of
this plate descends six inches lower than the fire-bars into the ash-pit, and the
space divided off by this plate is provided with a door at bottom to admit
air or not at pleasure, the effect of which would be twofold, 1st, to prevent
direct communication of the intense heat of the furnace to the oven; and,
2ndly, to meet the smoke on its way to the flues, and thereby causo its
combustion.
The next improvement relates to the building of the oven front. in which
I omit the brickwork, or the greater part thereof, immediately in front of the
oven door, by which arrangement a recess is formed in the oven front enabling
the operative to go close up to the doors of the oven to put the bread and
other goods therein as well as in drawing it out. The advantages of this plan
are threefold, 1st, it enables the oven to be constructed nearly square, that is
to say, with internal shoulders fitting in the front corners, thereby obtaining a
larger oven in the same space than in an ordinary oven (coal oven) of similar
size; 2ndly, it enables the workman to get at the goods in the front corners of
the oven; and, 3rdly, it gives the operative greater command over the goods
to be baked in placing them in and withdrawing them from the oven.
Another part of my improvements consists in forming two doors in the oven
front at equal distances from each side, so that two men may set or place
things to be baked in the same oven at the same time; this, combined with
the short length of the oven from back to front, as before mentioned, enables
the goods to be placed in the oven with the saving of time and labour already
described, and with the advantage of having bread better baked and more
profitable to the baker. In case where it is not desired to have two doors, or
the width of the building does not admit of it, the oven may be built narrower
and of proportionately greater extent from front to back; and in some cases,
where it is possible and desirable, I form one or more doors at the far end of
the oven, so as to withdraw the bread first that was first introduced.

page_text: Another part of my improvements consists in disposing a gas burner in each
internal angle of the oven nearest the front, before which I dispose an iron
frame, secured in brickwork, having a glazed door, behind the gas is a
reflector to throw the light towards the opposite corners of the oven obliquely.
I further provide channels, if necessary, for the entrance and escape of air and
gases independent of and separate from the area of the oven. The advantage
of this is, that it affords a better view of the bread and other goods while
baking and setting without the smoke and heat from the gas coming in the
face of the operator.
Another part consists in keeping the chimney bar about six feet six inches
from the ground or floor line, more or less, according to the size of the oven,
thereby forming a continuation upwards of the recess formed in the brickwork
at the oven door before mentioned, which. together with the absence of the
gas light from the door through which it is introduced from the outside every
time it is desired to view the bread, enables a man to breathe comparatively
pure air. Drying ovens can be built under these improved ovens as in those in
general use. Immediately over the mouth is disposed an inclined iron plate
forming an auxiliary flue just over the oven door to receive the first rush of
steam and heat as it passes out of the oven. Over the oven door, and in con-
nection with the flue just mentioned, is a flue to carry off the steam and
heat into the atmosphere, or into any flue not being the one belonging to
the oven furnace.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Smith in the Great Seal Patent Office on the
3rd September 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
SMITH, of York Street, York Road, Lambeth, in the County of Surrey, Builder
and Oven Builder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of March, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Frederick Smith, Her special licence that I, the said Frederick
Smith, my executors, administrators, and assigns, or such others as I, the
said Frederick Smith, my executors, administrators, and assigns, should at

page_text: any time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
use, exerciso, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN THE ARRANGEMENTS AND CONSTRUCTION OF OVENS," upon the condition
(amongst others) that I, the said Frederick Smith, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Smith, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):
-
In carrying out my improvements I propose to construct a chamber or
oven, say, for example, eleven feet from side to side and eight feet from front
to back, inside measurement; this of course may be varied according to re-
quirements, as also the brickwork round same, which would vary from one
and a half to three bricks in thickness. The bottom of the oven I support on
T iron girders resting on piers of brickwork, from each of which should
be stretched a fire-tile covering the space between girders, the under part of
tile forming the upper surface of the flues under the oven, or a series of flat
arches might be substituted, and on this again would be bedded the ordinary
red oven or other fire-tile as the sole of the oven. In places where an inferior
description of fuel is used I cover over the flue space with iron plates instead
of fire-tile, and on them put ordinary oven or other fire-tiles. The top of oven
is also supported with T iron girders, or girders made as a cross, thus +, so
that a portion might descend into oven at top, which would tend to prevent
the rapid passage of heat, steam, and gaseous products. The height of
crown or top of oven from the bottom or floor would depend upon the
description of goods to be baked, but would range between fourteen and
twenty-four inches. Under the bottom and over the top of oven soot doors
are placed, so as to clean out the flues at any time, or if that plan should
in some cases be found inconvenient, then an arrangement could be made for
lifting some of the fire-tiles in the bottom leading to flues, and a similar
arrangement could be adopted outside at the top of oven for access to the
upper flues in a like manner by taking up a stone or tile with which the oven

page_text: would be paved on the top. On the top of the oven the flue space is
partitioned so as to form flues to and fro over the top of the oven, and should
be about seven inches from bottom to the covering of the flue. The fluo space
below the oven is similarly partitioned, and should be nine inches deep, more
or less, to allow for the depth of girder descending therein. On the girders
that support the top of the oven I place fire-tiles or flat arches properly bedded
and flushed on girders before mentioned. For more effectually keeping in the
steam and heat of the oven I propose to put a series of sheets of wrought iron
rivetted together, and firmly bedded on the top of the fire-tiles and girders
before mentioned. In cases where greater economy is required instead of the
plate iron, as aforesaid, I use and bed plain tiles. On the top of the plate
iron I build brickwork half a brick thick to form the flue partitious, and on
this are thrown across either fire-tile or stone coverings; iron might be used;
this is then filled in with sand or other material to the thickness of two feet
six inches, more or less, according to circumstances, for the purpose of
retaining the heat of the oven. The flue passage thus passes from the furnace
over the top of the oven in a serpentine or zig-zag course down a chamber in the
brickwork at side of the oven, and then in a serpentine course under the oven,
flue thence passes down a channel in the front brick work of the oven near
to the furnace, in which channel a damper is disposed. This flue is connected
to an ordinary chimney in the usual manner; this damper and a ventilator in
ash-pit door commands the draught, and consequently regulates the heat of
the oven.
The caloric of the hot air or smoke in describing a serpentine or a
to-and-fro course above as well as under the oven, is more readily and per-
fectly absorbed then by any other arrangement heretofore adopted in ovens.
The heat is obtained from a furnace, the fire-bars of which would be, say 24
inches long, more or less, according to the size of the oven, with dead plate,
about nine inches wide in front of same to lessen the radiation of heat into the
bakehouse. The furnace is placed at either the right or left side of the oven,
the door of which would stand inwards eight inches, more or less, according to
the size from the line of the oven front. By the side of the furnace and next
to the oven is placed an iron plate disposed near to the wall or side of the
furnace in a position inclined thereto, so that the space narrows towards the
top, which would be level with the bottom and commencement of the upper
system of flues. The bottom of this plate descends six inches lower than the
fire-bars (six inches into the ash-pit). The space divided off by this plate is
provided with a door at bottom in the ash-pit to admit the air or not at
pleasure the effect of this arrangement is twofold: 1st, to prevent direct
communication of the intenser portion of heat of the furnace to the oven;

page_text: 2ndly, to meet the smoke on its way to the flues, and thereby causing its
combustion.
The next improvement relates to the building of the oven front, in which I
omit the brickwork or a greater part thereof immediately in front of the oven
door, by which arrangement a recess is formed in the oven front, enabling the
operative to go up to the doors of the oven to put the bread and other goods
into the oven, as well as in drawing it out. The advantages of this plan are
threefold: 1st, it enables the oven to be constructed nearly square, that is
to say, without shoulders (internal filling in the front corners), thereby
obtaining a larger oven in the space occupied by an oven (coal oven) of
similar size; 2ndly, it enables the workmen to get the goods in the front
corners of the oven; and, 3rdly, it gives the operative greater command over
the goods to be baked, and in putting them in and drawing them out of
the oven.
Another part of my improvements consists in forming two doors in the oven
front only at equal distances from each side, so that two men may set or
place goods to be baked in the same oven at the same time; this, combined
with the short length of the oven from back to front, as before mentioned,
enables the goods to be placed in or removed from the oven with the saving
of time and labour already described, besides the advantage of being better
baked bread and more profitable to baker.
In cases where it is not desired to have two doors, or the width of the
building does not admit of it, the oven can be built narrower and of pro-
portionately greater extent from front to back. In some cases, and where it is
possible and desirable, I form one or more doors at the far end of oven, so as
to withdraw the bread first that was first introduced.
Another part of my improvements consists in disposing a gas burner in
cach internal angle of the oven nearest the front, and before which 1 dispose
an iron frame secured in the brickwork, having a glazed door or front; behind
the gas is a reflector to throw light towards the opposite corner of the oven
(obliquely). I further provide, if necessary, channels for the entrance and
escape of air and gases to and from the burners, independent of and separated
from the area of the oven; the advantage of this will afford a better view of
the bread while setting and baking the the goods without smoke and beat
from gas coming in the face of the operator.
Another feature in the arrangements cousists in keeping the chimney bar six
feet six inches from the ground, more or less, according to the size of the oven,
and thereby forming a continuation upwards of the recess formed in the
brickwork by the oven door, and before mentioned, which together with the

page_text: absence of smoke from the gas light enables the man to breathe a comparatively
pure air Drying ovens can be built under these ovens the same as in those
now in general use. Immediately over the oven mouth an inclined iron plate
forming an auxiliary flue is disposed just over the oven door to receive tho
first rush of steam and heat as it passes out of the oven. Over the oven
door and in connection with flue just mentioned there should be a flue to carry
off the steam and heat into the atmosphere, or into any flue not being the one
belonging to the oven or furnace.
As a modification of the foregoing arrangement of oven, I propose to
construct the furnace of the oven so that the level of the bars would bo
about one foot two inches below the level of the bottom of the oven, and pass
the heat and flame from the furnace at once under the oven instead of over
the top, as before, for the purpose of giving a greater bottom heat to the
bread if it is desired. In connection with this and instead of the one damper
before named, I employ two working in combination, and so arranged that
one door serves for two openings, and must necessarily always leave one way
open; by these means the course of the firo may be made to pass under the
bottom of the oven first, or over the top, at the will of the person in charge.
Generally one of these dampers would be placed at the head of oven at the
farthest corner from the furnace, so that the heat would pass along the flues,
and afterwards descend into another flue built under the serpentine flues
leading directly to the main flue. To consume the smoke from the furnace I
sometimes admit air from exterior (and not through ash-pit), which is
regulated by an ordinary ventilator, and caused to pass between fire-brick or
iron shield, before named, and the oven, and to be discharged either at the
upper or lower part to meet the smoke in its passage to the flues. For tho
admission of air, and where the heat passes direct from the furnace under the
oven, I prefer to dispose the air passage in the body of the wall, separating
the furnace from the oven with an opening upwards to the upper flues, as also
one at bottom to the lower flues, but which latter is cut off by a damper when
not required. This air space besides conducting air to the flues protects the
oven from the intense contact heat of the furnace, and I dispense with the
plate before mentioned for that purpose. The furnace doors and frames as
well as the ash-pit may be of the usual description, or may comprise two extra
doors, one additional furnace and ash-pit, with additional spaces between the
same, which can be perforated, so as to admit cold air to the furnace; the ash-
pit door being closed keeps the heat from the bakery. When the oven has
finished working a small door is opened in the ash-pit leading into main flue,
so as to continue the current of air through the door, as before mentioned.

page_text: DESCRITION VE DRAWINGS
Fig. 1 represents a front elevation of an oven constructed according to my
Invention; Fig. 2, a lateral vertical section; Fig. 3, a horizontal section,
taken through the oven on line a, a, Fig. 1; Fig. 4, a horizontal section of the
upper flues on line b, b, Fig. 2; and Fig. 5, a horizontal section of the lower
flues on the lines c, c.
A is the furnace; B, B, the oven, which, as scen, is furnished with two
doors C, C, in front, and if convenient may be provided with two similar
doors C, C, at back, in order to remove the goods at the back part first, they
having been soonest introduced, as before explained; D, D, are fire-tiles
forming the bottom of the lower flues W; on this the brick piers E are
raised, forming the serpentine course of the flues; on these the bottom F of
the oven B rests, as also on iron girders G stretched across from front to back
walls. The bottom FI make of a double thickness of fire-tiles; E are the
girders for the support of the crown of the oven, also stretched between the
front and back walls; the oven crown is also of fire-tiles d, d, fitted between the
girders, as seen; on the tiles d, d, are built the dividing piers I, I, forming
the upper serpentine flues X, and upon these and the girders K, K, are laid
the fire-tiles forming the top of such flues, the tiles being fitted between the
girders, as before mentioned. The whole of the other brickwork is built
somewhat as in ordinary, and will not require any description. L is the flue
communicating between the upper and lower serpentine flues, and M the
passage leading from the latter to the chimney. It will be readily understood
that in an oven so built the heat and products of combustion pass from the
furnace by the opening N to the upper flues X, and traversing them back-
wards and forwards over the oven, then descend by passago L to the lower
series of serpentine flues, and so crossing and recrossing the bottom of the oven.
The oven is thus subject to the heat throughout a great length of flue surface,
and extending almost entirely over the oven surface; P is the plate dividing
off the air space R in the furnace, to protect the oven from the intense contact
heat of the fire, and also to provide for the passage of air to be admitted to
mix with the smoke at N before entering the flues. I prefer that this plate
be made of a fire-tile, or other material to resist the action of the fire lying
against it. T, T, are the gaslight recesses in the front corners of the oven;
and S, S, passages in the brickwork for air, and for lighting and turning off
the
gas; the spaces in which these gas burners are disposed are enclosed from
the oven by glazed metal frames U, U, and the lights are provided with

page_text: reflectors placed so as to reflect the light diagonally across the oven. The
spaces V, V, in the brickwork of the oven I make six feet six inches in height
from the floor, so that a man may stand close up to the door while introducing
goods, or withdrawing them from the oven without inconvenience.
Fig. 6 represents a longitudinal vertical section of an oven somewhat
modified from the foregoing, and which can be arranged at will, so that the
heat and products of combustion shall at pleasure either pass first over the
top, and then through the under flues, as before, or shall avoid the upper flues
and pass direct from the furnace to the lower flues. In this Figure also I
have represented the air space for protecting the oven from the intense contact
heat of the furnace in the wall, and utilizing that space for the admission of
air either to the upper or lower flues. With the exception of the above and a
further arrangement of the connecting passages of flues the oven is the same
as before described. In this case the fire-bars are placed lower, so that a
passage may be made directly to the lower flue W; this is furnished with
a double damper frame e, e, the one part being fitted to the passago Y, and
the other to passage M. leading from flues W to the chimney; a single
damper fis pivoted between these frames, which can be disposed so as either
to close the passage Y or M at pleasure. A like double damper e', e, f, is
applied between the passage L and flues W, which either closes the com-
munication between L and flues W, or between flues W and an auxiliary
passage M' to the chimney. The dampers f and f' may be moved separately
by hand, or may be connected by rods and levers, so as to move simultaneously,
and so that when passage M is closed passage M' is open, and at same time
L is closed and Y open, and vice versa. It will be observed that the effect of
this is, that the heat and products of combustion may either be allowed to
circulate over and under the oven flue passages ✗ and W, or only under the
oven in the flue passages W, the first producing a slow general heat, and the
latter a strong bottom heat, as may be required in baking according to
the goods under operation; is the air space before mentioned as protecting
the oven from the contact heat of the fire. I form a communication p from
the exterior atmosphere with this flue, and fit it with a regulator to regulate
the supply of air to be admitted. When the regulator is open air will at all
times enter space 2, and if the heat and flame leads from the furnace into
flues X, it will pass upwards and mix with the products of combustion at N,
and besides serving the purpose before described of protecting the oven from
contact heat of furnace, will further mix with such products, and tend to
promote their consumption. When the flue passage is interrupted at L, the

page_text: air in L will lead downwards and mix with the products of combustion at Y.
The air space is shown dotted in plan, Fig. 8. r, r, are flue doors for
cleaning out the flues, while s, t, represent the furnace and ash-pit doors.
Having described the nature of my invention, and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent is, the general arrangement and
construction of oven, herein-before described and represented in the Drawings
annexed.
Frederick Smith have hereunto set my