In- PROVEMENTS IN THE CONSTRUCTION OF OVENS, APPLICABLE ALSO FOR THE PURPOSES OF ECONOMIZING FUEL IN FURNACES GENERALLY
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
THEODORE MAILLARD ROCHET, of Paris, in the Kingdom of France, but now
of Lincoln's Inn Fields, in the County of Middlesex, Gentleman, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twentieth day of March, One thousand eight hundred and
forty-five, in the eighth year of Her reiga, did, for Herself, Hier heirs and
successors, give and grant unto me, the said Louis Theodore Maillard Rochet,
my exors, adñiors, and assigns, Her especial licence, full power, sole privilege
and authority, that I, the said Louis Theodore Maillard Rochet, my exors,
adiors, and assigns, and such others as I, the said Louis Theodore Maillard
Rochet, my exors, adñiors, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within that part of Her Majesty's United Kingdom of Great Britain and
Ireland called England, Her Dominion of Wales, and Town of Berwick-upon-
Tweed, in the Islands of Jersey, Guernsey, Alderney, Sark, and Man, and also
in all Her Majesty's Colonies and Plantations abroad, my Invention of "In-
PROVEMENTS IN THE CONSTRUCTION OF OVENS, APPLICABLE ALSO FOR THE PURPOSES OF
ECONOMIZING FUEL IN FURNACES GENERALLY;" in which said Letters Patent is

page_text: contained a proviso obliging me, the said Louis Theodore Maillard Rochet, to
particularly describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and to cause the same to be enrolled in Her Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same, reference
being thereto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Louis Theodore Maillard Rochet, do hereby declare the nature of my said
Invention, and in what manner the same is to be performed, to be fully
described and set forth in and by the following statement and Specification
thereof, reference being had to the accompanying Drawings (which Drawings
I declare to belong to and form part of such Specification) by the letters and
numeral figures marked thereon for the purpose of such reference, that is
to say-
The nature of my said Invention consists in improvements in the con-
struction of ovens, which improvements are applicable to the purposes of
economising fuel, in the construction and management in the economy of fuel
in furnaces; and I declare the manner in which the same is to be performed
or carried into practical effect to be as follows:-
The Drawings, which are respectively marked Drawing No 1, Drawing No 2,
and Drawing N° 3, contain representations, in different Figures and in different
points of view, the mode of construction and the combinations under and
by which perform the same. I therefore proceed to describe such said
Drawings, and the Figures they contain, in the order of their enumeration, as
follows:-
DESCRIPTION OF THE DRAWINGS.
Drawing No 1, Figure 1, represents a view in front elevation of the furnace;
Figure 2 is a transverse vertical section of the same; Figure 3 is also a
transverse vertical section of the furnace, taken parallel to that shewn
in the Figure 2, and passing through the air flues behind the fire-place
of the furnace; Figure 4 is a vertical and longitudinal section, taken
through one of the air flues of the furnace, and extending through the entire
depth of the same. In this Figure the position of the boiler is shewn drawn
in red lines at A, A, A, A, A, of the fire-place B. and its fire-bars b, b, b,
with the ash-pit C, all which parts are shewn in transverse section in the
Figure 2. Figure 5 is a view in horizontal section of the air flues E, running

page_text: beneath the ash-pit C. Figure 6 is a horizontal view of the vaulted roof x, x,
above the fire-place B, perforated by the vertical passage y, y, y, y, &c., forming
channels of communication between the heating tubes, , and the boiler A.
In the above described Figures 1, 2, 3,-4, 5, and 6, the same letters of
reference are set against or refer to the same parts respectively; A being the
boiler; B, the fire-place; C, the ash-pit; E, air flues passing beneath the ash-
pit, and circulating round about the fire-place in its upper as well as its lower
parts. The said air passages or flues are coloured blue in each of those Figures
of the Drawings in which they occur. The external air is admitted to the air
flues above described by the apertures E, E, E, &c. (seen in front view in the
Figure 1), the number of which may be without limitation. These apertures
can be opened or closed at pleasure by the sliding plates F. The air so
admitted circulates through the air flues, which may be variously disposed.
The air so heated then passes into the fire-place B, y the lateral apertures
G, G, of the fire-place B, and the flues or passages G. In this system of
heating, the first condition of the combustion is that of slow or moderate
rate of calorific action, such action being principally radial, and in a gentle
flow of the air heated to work out such effect in practise. A mass or
layer of the combustible material used (which should be coal of slow com-
bustion, as stone coal, culm, or anthracite, rather than a coal of highly
bituminous character,) must be deposited on the grate in a thickness of from
about one and a half to two inches, and such deposition of the combustible be
repeated at intervals of from four to six hours, according to the rate and
progress of its activity of combustion, so as to preserve as nearly as possible
the constant or uniform thickness of the mass. At the commencement of the
combustion of the charge of the furnace much carbonic oxide is produced; but
this, by its intermixture with the heated air supplied by the openings of the
passage E, is rapidly converted into carbonic acid gas. In order to produce
this mode and rate of action of the furnace, and to ensure the admission of
atmospheric air with accuracy in the quantity precisely necessary to a perfect
combustion, the register H (which is shewn in the Figure 4) is considerably
lowered in its position in the passage by which the heated air is conveyed to
the main chimney flue of the fire-place, whilst the sliding plates which regulate
the outer apertures E, of the air flues, are adjusted in correspondence therewith.
The maximum quantity in which the register H, and the sliding plates of the
apertures E. will require to be closed, will be, when the escape of carbonic acid
gas by the openings E takes place in a sensible quantity. An aperture of not
less than from one inch and a half to two inches square, or from two inches

page_text: and a quarter to four inches area, must be formed at the lower part of the
principal chimney flue or shaft, and is furnished with a door; this is opened
when the draught is required to be of moderate rate or power; and on the
other hand, when the draught is required to be quicker, then the sliding plates
of the passage E are to be opened. Behind the fire-place and beneath the
farthest extremity of the tubes Z, Z, (as shewn in the Figure 4 of the Drawing
No. 1) there is a close air chamber J, having an exit passage K, through
which air or moist vapours may escape, and will thus assist combustion. It
has also another useful purpose, when it is required to maintain the existing
temperature of the furnace; by keeping the register II and the plates E nearly
closed, the products of combustion, azote, carbonic acid, and steam, pass therein,
and are partially condensed. It further effects an insulation, for the heat
generated, by the interposition, to the amount of its extent, and the extent of
the other air chambers and passages, of so much in quantity as their amount of
area of an imperfect conducting medium.
In the Drawing No. 2 is shown the construction and arrangement of another
modification of boiler, in which the heating vessel is of spherical form. The
principles of action on which this construction and arrangement is made is the
same as that represented in the Drawing No. 1, and above described, differing
only in the necessary variation in the disposition of the parts, resulting from the
different form and dimensions of the boiler and the heating vessel.
The Figure 1 represents by A, A, the boiler with its heating vessel in a view
of external side elevation.
The Figure 2 represents the construction and arrangement of the entire
furnace in a view of vertical section, taken through the length of the boiler.
The Figure 3 represents a view of horizontal section, the air passages taken
in a line beneath the ash-pit D of the furnace.
The Figure 4 represents a view in a horizontal section through the furnace,
taken above the fire-place, the upper plan or appearance of the vaulted rood of
such fire-place.
In the Figure 2, A marks the heating vessel of the boiler; B, the fire-place;
C, its ash-pit; D, D, D, the air flues or passages which circulate beneath and
all around the fire-place. The point of admission for the atmospheric air
necessary to support combustion is at the mouth of the air passage E (shewn
in the Figure 3), and it is fitted with a sliding door or plate. In operation,
the air enters by the passage E, and passes onwards to the centre of the space
beneath the ash-pit, and thence is distributed through the entire extent of the
air passages, and after such transit passes off by several small conduits of

page_text: discharge towards and respectively into the circular range of apertures a, a, &c.
in the vaulted roof of the fire-place. (These are shewn in the Figure 4.) The
atmospheric air so admitted and thus circulated determines the combustion in
the furnace; and the gaseous products of such combustion spread themselves
under and about the spherical heating vessel A, and its boiler, through its
entire length, and thence passes off into the principal chimney flue or shaft by
a flue having an opening fitted with a register plate, as described in and
respecting the construction shewn in the Drawing No. 1. Before their
admission to this flue, however, they are made to pass into and circulate
through a tube or passage containing the necessary supply of water for feeding
the boiler, for the obvious purpose of a previous preparatory heating thereof.
It will be obvious that the combustion is governed by the same principles of
construction as those herein-before described with reference to the Drawing
No. 1. F marks a close air chamber, having an aperture opening into the
flue near to the boiler also, as in the construction herein-before described
with reference to the Drawing No. 1.
The Drawing No. 3 represents, in Figures of external elevation, vertical
section, and horizontal section, the construction and arrangement of the
furnace and oven for the general service and the operations of bakeries and
baking. The Figure 1 represents the construction of an oven, as taken in a
view of front elevation. The Figure 2 represents the same construction in a
view of transverse vertical section.
The Figure 3 represents a view in horizontal section of the Figure 2, as
taken through the line A*, A*.
The Figure 4 represents a second view in horizontal section of the Figure 2,
as taken through the line B*, B*.
A shews an air flue, communicating by a passage to a valve or register
opening into the bottom of the baking oven; this lower passage also has
communication by several apertures with the curvilinear flue or passage C.
The flue or passage C also communicates by several small pipes or passages,
which terminate in the form of T, with each of the flues or outlets for smoke
or gaseous product D.
The flues or outlets D have their openings from the two fire-places E, E,
which have a free communication with each other by the passages F. At the
middle portion of the fire-places, and passing around them, are the air pas-
sages or flues G, to which air is admitted from the exterior of the structure.
and which, after taking a returning direction, terminate near to the mouth of
the oven in the passage or flue H, which passes above the fire-places. The

page_text: cooling the oven.
passage His composed of several compartments, and communicates with the
baking oven by two conducting passages J, situated on each side of its mouth,
and communicating also with the tube of the passage B. K shews a second
passage above the fire-place, and serves the purpose of
When it is too much heated, cold air enters by several apertures to this
passage, and leaves it at its back or remote end, by a pipe which is fitted
with a valve opening into the chimney flue beyond the above-mentioned
passage J. M shews a large oven, for the purpose of baking bread, having
the registering passage J, above mentioned, or a greater number, if required.
At the back of the oven an exit pipe or passage communicates with the
chimney flue, for the purpose of cooling the oven when it becomes too hot in
practice. N shews an open space or flue, through and by which the smoke
and gaseous products from the passages D pass off, and in which their com-
bination takes place with the heated air of supply delivered therein by the pipes
of T shape, herein-before mentioned. By this combination the temperature
is much encreased, and sometimes even to actual ignition. They escape by
the chimney flue O, which is fitted at its entrance with a valve Q, of cylindrical
form, and the position of which can be adjusted to any part of the passage in
which it is fitted. The chimney flue O serves also to heat a small boiler W,
and the flue has also a register plate P. In cases in which the circumstances
permit it, this chimney flue is made to descend, and takes the place of the
passage A, afterwards ascending on the opposite side of the structure.
Having now described the nature of my Invention, and also the manner
in which the same is ascertained and carried into effect, I now declare that I
claim as of my Invention therein the particular principles of construction, and
the modes of arrangement of the mechanical parts, by and on which such
construction is formed, for the purposes and intention of my said Invention, as
they are herein-before stated, as and in the manner in which such principles
of construction and such modes of arrangement of the mechanical parts of
the same are herein-before set down, described, and specified. These I claim
as of my Invention herein, together with such modifications of form and dimen-
sions of the component parts thereof, and changes of material consequent
thereon, as form an obvious extension of the same principles of construction
and arrangement of parts.
In witness whereof, I, the said Louis Theodore Maillard Rochet, have
hereunto set my hand and seal, this Twentieth day of September, in
the of our Lord One thousand eight hundred and forty-five.
year
MAILLARD ROCHET. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Twentieth day of September,
in the year of our Lord 1845, the aforesaid Louis Theodore Maillard Rochet
came before our said Lady the Queen in Her Chancery, and acknowledged
the Specification aforesaid, and all and everything therein contained and
5 specified, in form above written. And also the Specification aforesaid was
stamped according to the tenor of the Statute made for that purpose.
Enrolled the Twentieth day of September, in the year of our Lord One
Enrolled the Twentieth day of September, in the year of our Lord One
thousand eight hundred and forty-five.