IMPROVEMENTS IN FURNACES OR FIRE-PLACES
Year: 1855

page_text: ETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, and of Glasgow, North Britain, Gentleman, for
the Invention of "IMPROVEMENTS IN FURNACES OR FIRE-PLACES."-A com-
munication from Nicolas Francois Corbin Desboissierès, of Paris, in the
Empire of France, Metallurgical Chemist.
Sealed the 10th August 1855, and dated the 18th June 1855.,
PROVISIONAL SPECIFICATION left by the said John Henry, Johnson at
thic Office of the Commissioners of Patents, with his Petition, on the
18th June 1855.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the, County of
Middlesex, & of Glasgow, North Britain, Gentleman, do hereby declare the
nature of the said Invention, for "IMPROVEMENTS IN FURNACES OR FIRE-PLACES,".
communicated to me from Nicolas Francois Corbin' Desboissieres, of Paris,.
in the Empire of France, Metallurgical Chemist, to be as follows:-
This Invention relates to an improved construction and arrangement of
furnaces employed in various manufactures where furnaces are used, whereby
a more perfect system of combustion is obtained. In order to avoid the."
pernicious formation of carbonic oxide in the furnace, it is not only necessary:
to supply a sufficient quantity of air, but it is also necessary that it should
be forced into the furnace_under_considerable pressure,-in-order-that-it may
penetrate every part of the fuel & acidify it. For this purpose, it is pro

page_text: posed to construct the furnace in such a manner that it may absorb in the
same time and under the same necessary pressure the same weight of air.
The grate is made ridged, easily cleaned, and constructed so as to avoid
heating, whereby the bituminous substance may be cooled or coagulated on
the sides of the fire bars. The furnace is constructed of a parabolic form, as
this shape is the best adapted for preventing over-heating, & facilitating
the direct radiation of the heat to any apparatus or material to be acted upon.
The height above the grate should be about six feet, more or less, for a grate
of about three feet square, this height being the most advantageous for facili-
tating the actions and re-actions of chemical affinity, by avoiding the obstacles
which counteract them.
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
18th December 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
and of Glasgow, North Britain, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of June, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others
as I, the said John Henry Jolinson, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN FURNACES OR FIRE-PLACES," a communication from Nicholas
Francois Corbin Desbossieres, of Paris, in the Empire of France, Metallurgical
Chemist; upon the condition (amongst others) that I, the said John Henry
Johnson, by an instrument-in writing under my hand and seal, should par-
ticularly 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.

page_text: NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the sail Invention, and in what manner the same is
to be performed, to be. particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,' and'
to the letters and figures marked thereon, that is to say:-
*. The said Invention relates to an improvedl construction and arrangement of
furnaces employed in various manufactures where furnaces are used, whereby
a more perfect system of combustion is obtained: In order to avoid the
pernicious formation of carbonic oxide in the furnace, it is not only necessary
to supply a sufficient quantity of air, but it is also necessary that it should be'
forced into the furnace under considerable pressure; in order that it may
penetrate every part of the fuel and acidify it. For this purpose. it is proposed
to construct the furnace in such a manner that it may absorb in the same
time and under the same necessary pressure the same weight of air! The
grate is made ridged, easily cleaned; and constructed so as to avoid heating,
whereby the bituminous substance may be cooled or coagulated on the sides'
of the fire bars. The furnace is constructed of a parabolic form, as this 'shape'
is the best alapted, for preventing over-lieating, and facilitating the direct
radiation of the heat to any apparatus or material to be acted upon. The
height of the furnace roof above the grate should be about six feet, more or
less, for a grate about three feet square, this height being the most advantageous
for facilitating the actions and re-actions of chemical affinity, by avoiding the
obstacles which counteract theni..
An elevation-and various details of this furnace are represented drawn to a
scale of one-twentieth on the annexed, Sheet of Drawings: Figure 1 is a bori-
zontal section of the fire-place, taken through the line A, B, in Figure 2: The
rectangular grate A is here represented of about three feet square, and composed
of twenty triangular bars of wrought iron. The side of these bars upon which
the fuel rests has a width of about one inch and three quarters" width, the bars!
being separated from one another by a uniform space of about five-sixteenths
of an inch; destinedi to allow of a passage for the air; the two large sides of
the triangle formed by a cross section of these bars; and plainly shewn at
Figure 3; have a width of about ten inches: Thus the grate is heated by
the incandescent fuel which covers a surface of about two feet nine inches
square, and is cooled by the contact of the cold air on a surface of about
twenty-six feet square. Thus arranged, the bars, whatever may be the tem-i
perature of the-furnace, do, not beconie heated, but congeal on their surface
thie--liquified bitumen of the coal or other fuel used: Thus arranged, the
twenty bars. which form-the-grate are maintained in their positions in a
:

page_text: perfectly rigid state by the three cast-iron bearers B, B, B, shewn in trans-
verse section at Figure 2, and in longitudinal section C, C, Figure 3; and also
by the bolts, by which they are held to the plate D, Figure 2, and at the other
end to the angle E, seen in transverse section at Figure 2, and in elevation at
Figure 5. Thus fixed, the grate is closed by the cast-iron door and fire brick F
seen in horizontal section Figure 1, in vertical section Figure 2, and in front
elevation at Figure 5. This door can be easily secured by the wronght-iron bar
G, Figure 1, which is also seen in transverse section Figure 2, is end elevation
at Figure 4, and in front elevation at Figure 5. This moveable door rests upon
the plate formed by the angle iron E, the vertical side of which plate. is pierced
with holes, through which passes freely the wrought-iron pickers or cleaners,
shewn at a one-tenth scale at Figure 7. These holes can be stopped by the
moveable plug of wrought iron, Figure 8, also drawn to a tenth scale. In order
to clean the grate and the furnace herein-before described, it is simply neces
sary to withdraw the bar G, and to remove the moveable door E, by drawing
down the lever H, Figure 5, which should be furnished with a counterweight in
order to facilitate the operation.
The fire-place of the combustion furnace is enclosed by the bridge I, seen
in horizontal section Figure 1, in vertical section Figure 2, and in elevation
Figure 3, and is covered in by the arched roof K, K, K, Figure 2, which
is about six feet above the grate, the roof being shewn broken away at L, L, L,
Figures 1 and 2. The space behind the bridge I should contain whatever is
required to be heated or operated upon. Supplied by a ventilator, or by any
other suitable blowing machine, the air which feeds the furnace enters by the
conduit M, seen in transverse section Figure 1, and vertical section Figure 4,
into the reservior N, arranged under the grate, and closed by the door of slieet
iron O, scen in vertical section Figure 2, and in elevation Figure 5. Figure 1
shews, as well as the grate herein-before described, a horizontal section of the
preparatory furnace P, seen also in vertical section Figure 3. This furnace is
fitted with a fire door Q, seen in horizontal section at Figure 1, in vertical
section in Figure 3, and in elevation at Figure 6. The fire-place of this furnace
is about three feet in length, two feet six inches in breadth, and twenty inches
in height. The body of the furnace.is formed of fire bricks, arranged to be on
the same level as the grate A. As carbonated air is capable of spontaneous com-
bustion without the emission of smoke, since, when the combustible material is
pulverised, as I propose to use it, it is permerable to oxygen, the water which is
retained by the fuel when it is burnt in this finely divided and mixed state
finds itself on all sides in contact with coke in an incandescent state, which
facilitates the action of the reciprocal chemical affinity between the carbon

page_text: and the oxygen of the water, which combine to form carbonic acid, leaving free
hydrogen. This hydrogen, however, is enveloped on all sides by free oxygen,,
with which it combines, thereby restoring the heat which was neutralised by the
decomposition of water; these are the conditions, without which it is impossible
to reduce the smoke usefully and practically, and effect perfect combustion.
The mixed combustion furnace, illustrated by the Drawings annexed, fulfils.
these conditions, as well as that of burning the carbonated air.
In fact, when the grate A, herein-before described, is lighted, the furnace P
soon arrives at the same temperature as that of the principal combustion.
furnace. The fresh coal introduced into this furnace is distilled as in a coke
furnace,. and attains by degrees the red heat; the combustible gases and the,
steam filling the upper part of the preparatory furnace to a depth of about
4 inches, and not being able to escape by the fire door Q, which is closed, they.
pass along into the combustion furnace under the arch R, seen in elevation
Figure 3. A current of air flows out from the air passage M and pipe S, seen-
in plan Figure 1, in transverse section Figure 3, and in elevation, with valve, at
Figure 4, is continually blowing downwards by the orifice T, having a diameter.
of about five-sixteenths of an inch, and a length of about two feet seven inches;
the mouth of the fire-place P being thus, as it were, closed by a sheet or current
of heated air. This current of air forms in reality an unavoidable barrier, which
the combustible gases on leaving the furnace P must pass through and be.
burnt, whilst the smoke which is brought in contact with the combustibles_
which are at a white heat is decomposed, the hydrogen produced by the
decomposition burning constantly as it encounters the currents of air, thus..
realising an important advantage of a mixed combustion furnace.
The methods I have here described effect the complete consumption of
smoke and gas. The carbonated air in fact burns like a gas, as the carbon,
is in such a minute state of division as to be capable of immediate combi-
nation with oxygen to form carbonic acid. The pulverisation of the fuel is in
fact only a mechanical dilation, which supplies the place of a physical dilation..
Thus, then, it is not only when fuel is raised to a high temperature that it
is readily combustible, but when it is in such a state of division that each
particle comes in contact with the oxygen, so as to combine readily with it.
In order to shew one of the most important applications of my mixed;
.combustion furnace, and to facilitate the description of its coke furnace, the
apparatus is shewn in working order as applied to a welding furnace (which to
avoid confusion is drawn in dotted lines). It is seen in horizontal section
Figure 1, and in-vertical-section Figure 2; and in elevation Figure 4. It
is covered, as seen in Figure 2, by the prolongation of the arch K, K, K, of

page_text: the combustion furnace. The body of the furnace V; which should be furnished
as usual with a layer of fire clay of about eight inches in thickness, is inclined
towards the bridge 1 with a slope of about four inches in three feet.
The flame traverses the passage, 2, 2, seen in vertical section, Figure 2, to
the chamber A'; Figure 2, which conducts it finally under the steam boiler
which it is intended to heat, direct into the chimney; thus enveloped by the heat
lost from the furnace U, the coke furnace B', B', B', is heated like a retort.
The body of the soldering furnace cannot be cooled by distillation from the
coal, which disengages its oxygen while burning. The distilled gases and
vapours unite in the hollow C', C', there to enter two tubes of sheet-iron or
copper partly concealed in the bridge I. The elevation of the end of one of
these tubes D, Figure 2, shows also the manner in which they are fixed; it is
also seen in transverse section D', Figure 3, and dotted in horizontal section
H; Figure 2, together with their ten orifices G¹, G, G¹, G, G¹, and H, H;
H, H, H', in Figure 3, which introduce the gas upon the grate A: The
orifices G¹, G, G¹, G, G¹, are then imbeded and partly cut in the body of the
preparatory furnace P, the floor of which should be raised for that purpose
about six inches. This diminution in the capacity of the preparatory furnace
has only the inconvenience that the consumption of solid fuel is diminished in
the same proportion by the employment of the gas proceeding from the coke
furnace, which is charged by opening the doors 1, 1; 1', seen in elevation,
Figure 6. All the gaseous products which are formed in this furnace, divided
into ten equal parts by the ten apertures G and H, flow out into the mixed
combustion furnace above the grate, where they encounter air sufficiently
heated to occasion their immediate combustion, and to disengage the luminous
heat which facilitates the reduction of smoke, or, what is the same thing, the
decomposition of water by carbon. This method, which places in equilibriuni
the excessive heat disengaged in the furnace, requires at the same time some
care. The main portion A of this furnace should be carefully cleaned; and
the bars of the grate raked often enough to facilitate the constant flow of the
air. The coke furnace may be made to render its gas directly into the pre-
paratory furnace P, Figure 1, by the opening shewn in dotted lines K¹, Fig. 3.
It is simply necessary in order to burn the gas to augment (proportionally
to the quantity of combustion substance) the section of the orifice T,
Figure 3.
Thus arranged, the mixed parabolic combustion furnace herein-before
described, together with the soldering furnace and coke oven which it heats,
in order to show one of its applications, is enclosed in iron plates; these plates
are imbeded in the foundation walls, and are fixed there in the ordinary

page_text: manner, as seen in transverse section, Figure 2. The grate of my mixed and
parabolic combustion furnace is lighted. like an ordinary furnace at its fire
door L'; seen in horizontal section Figure 1, in transverse section Figure 3,
and in elevation Figure 4. This apparatus works thus under the atmospheric
pressure until the blowing is commenced, which supplies the necessary air.
The blowing is performed at an effective pressure of about half an inch of
mercury, that being the weight of air which the grate is capable of absorbing.
This pressure may, however, be raised with advantage in some cases to three-
fourths of an inch. The thickness of the layer covering the grate should be in
all cases proportionate to the density of the combustibles which form it and
to the pressure of the air.
.
The blast being ready. and the lighting completed, the attendant shuts the
door O, Figure 5, and opens the register of the wind door. The preparatory
furnace P shortly attains a red heat, and it is then supplied with a sufficient
quantity of combustible to last for an hour and a half to a height of about two
inches and a half; the distillation of the water and gas then commences, and
the attendant opens the cock S, Figure 4. The air flowing in also by the
orifice T inevitably burns the gas while disengaging the luminous heat, which
facilitates the consumption of the smoke. The lighting having been thus
completed, the attendant shuts the valve of the draught,-so as to cause a jet of
flame of about four inches and a half in length to gush out by a hole of about
one and a quarter inches in diameter, made in the door of the combustion
furnace, or of the furnace which it actuates. The apparatus is then worked
under the pressure which maintains this jet of flame; the combustion proceeds.
and the caloric exercises its beneficial effects. The smoke which only acci-
dentally escapes during its reduction cannot as an ordinary cases injure the
efficacious action of the mixed combustion furnace. This pressure, which is so
efficacious, forces the gas and the smoke contained in the preparatory furnace
to be expelled if the door of such furnace be opened before re-establishing
the draught.
In order to avoid the action of the sulphur on the iron when applied to
puddling furnaces, the fire bridge should be covered with vegetable fuel.
The fire bridge I is then furnished like the preparatory furnace, and fitted
with a grate and fire door O', Figure 4, by which it can be charged, cleaned,
and repaired.
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 I do not confine or restrict
myself to the precise-details-or-arrangements which I have had occasion to

page_text: describe or refer to, as many variations may be made therefrom. without
deviating from the principles.or main features of the said Invention.; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,
First, the system or mode of effecting a more perfect combustion. of fuel
and consumption or prevention of smoke, in the manner, herein before
described.
Second, the general construction and arrangement of furnaces: as herein-
before described, and the mode of using or working the same.
Third, the peculiar construction and arrangement of grate bars for the
prevention of overheating, as herein-before described.
Fourth, the system or mode, herein-before described, of introducing air
under pressure into the furnace for the purpose of preventing the formation
of carbonic oxide.
In witness whereof, I, the said John Henry Johnson, have hereunto 'set
my, hand and seal, the Eighteenth day of December, One thousand
eight hundred and fifty-five.
J. HENRY JOHNSON. (L.s.)