IMPROVEMENTS IN FURNACES
Year: 1876

page_text: LETTERS PATENT to James Harris Sanders and Samuel Sanders, both of
"
No. 25, Abchurch Lane, in the County of Middlesex, for the Invention of
IMPROVEMENTS IN FURNACES." A communication from abroad by Richard
Bernau and Gustave Oscar Alexandre Sommer, both of Liège, Belgium.
Sealed the 14th July 1876, and dated the 9th May 1876.
PROVISIONAL SPECIFICATION left by the said James Harris Sanders and
Samuel Sanders at the Office of the Commissioners of Patents on the 9th May
1876.
JAMES HARRIS SANDERS and SAMUEL SANDERS, both of No. 25, Abchurch Lane,
in the County of Middlesex. " IMPROVEMENTS IN FURNACES." A communication
from abroad by Richard Bernau and Gustave Oscar Alexandre Sommer, both of
Liège, Belgium.
The improved furnace, the subject of this Invention, differs from those with
horizontal hearths as generally used for puddling furnaces and boiler furnaces,
in that the fuel may be regularly spread over the entire surface of the grate or
fire-bars, and also by the particular construction of the hearth or dead plate, which
is so inclined that the fuel, in feeding, piles only into a moderately thick layer.
The coal resting on this inclined hearth is completely distilled by the intense heat
from a small grate placed below it as well as by the heat reflected from the walls
when at a white heat, and, after distillation, is completely burnt by the oxygen
passing through the grate. The residuum of the distillation is composed of slag
and of pure coke, this latter forming the fuel by which the fresh coal thrown into
the fire-placo is to be distilled. This system may be compared to a gas retort
heated interiorly, with this difference, that the combustion of the gases takes place
instantaneously upon the spot where they are produced.
As the coke burning on the grate gives passago to very little more oxygen than
is needed for its own combustion, there always remains in the flame an excess of freo
carbonic oxyd and carburetted hydrogen; the result being that the effect of the
flame upon the metal to be worked or treated in the furnace can be but slightly
oxydizing.
More or less oxygen may be supplied to the fire-place by diminishing or

page_text: increasing the number of the fire-bars of the grate, and thus enlarging or lessening
the open spaces in the grate.
As the fire-bricks would be rapidly deteriorated by the great heat produced
upon the small grate, there are formed in the walls of the furnace, on each side, two
corresponding horizontal conduits, the one placed above the other. Three vertical
conduits or air shafts are in communication with the upper horizontal conduit.
The cold air entering by the lower conduit spreads within the others, and leaves the
furnace by the top of the vertical conduits. A constant current of cold air being
thus kept up within these conduits, the walls of the furnace are thereby cooled
and last much longer than would otherwise be the case. The number and position
of these air conduits or flues may of course be varied; the feeding of this fire-
place is very simple. The fire is laid in the ordinary manner by first placing wood
upon the grate and a few lumps of coal upon the wood, and the feed opening,
which is funnel shaped, being then closed with lumps of coal the wood is lighted
from beneath. When the whole is alight, the coal stopping the feed opening is
pushed down and large and small coal, as it comes to hand, is fed into the tire-place
until the inclined hearth is covered with a layer of about a hand thick, in other
words, as much coal as necessary to the natural closing of the feed opening. The
fire is then allowed to make head, and in about two hours the interior of the fire-
place will have come to a red heat, the coal first placed upon the grate will then
have been completely burnt and that resting on the inclined hearth partially
distilled, that is to say, calcined. Then by incans of a poker or fire-iron of a
suitable size passed through the feed opening the coke is pushed about and the
calcined fuel on the inclined hearth spread equally over the grate, and coal is again
fed into the fire-place until the feed opening is closed.
The use of a good and pure coal in this improved furnace gives a greater saving
than the use of inferior coal, but it is in either case very considerable; the appli-
cation of this Invention to an ordinary furnace is very inexpensive, and the result of
this improved system as regards quantity and quality of production is as regards
quantity equal and as regards quality superior, this latter advantage being due to
the height of the fire-bridge which does not permit impurities to reach the bath with
such facility as hitherto.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Harris Sanders and Samuel Sanders in the Great Seal Patent
. Office on the 9th November 1876.
JAMES HARRIS SANDERS and SAMUEL SANDERS, both of Abchurch Lane, in the
City of London. "IMPROVEMENTS IN FURNACES." A communication from abroad
by Richard Bernau and Gustav Oscar Alexandre Sommer, both of Liege, in the
Kingdom of Belgium.
The object of this Invention of "Improvements in Furnaces" is to so construct
the fire-places of puddling, reheating, and other furnaces as to obtain an intense
and uniform heat and to effect a very considerable economy in fuel. When the
Invention is adapted to puddling furnaces it will also produce a better yield and an
improved quality of iron. Moreover, by the peculiar construction and operation of
the furnace the flame or heat produced by the combustion of the fuel or gases is of a
neutral character, that is, it is neither an oxidizing nor a carbonizing flame and does
not carry with it any uncombined carbon, nor is the flame of such an oxidizing
character as would be liable to injuriously affect the metal in a reheating furnace
nor the metallic surfaces of a boiler or evaporating vessel.
The improved furnace differs from those having horizontal hearths (as generally

page_text: used for puddling and reheating furnaces) in that the fuel will be regularly spread
over the entire surface of the grate or fire-bars, and of the hearth or dead plate in.
a thin layer instead of (when fed into the fire-place) piling itself up to a con-
siderable thickness or depth on the fire-grate and hearth. By so constructing the
fire-place the combustible gases will bo evolved from the coal in an uniform manner,
and will be burned in the fire-place or combustion chamber itself, so as to produco
therein an intense heat or volume of flame which is carried into the puddling or
reheating chamber (of the furnace or oven to which the improved fire-place is
adapted), instead of the combustible or carbonaceous gases and uncombined oxygen
being carried forward into the heating chamber in an undecomposed state as is now
the case. The effect of the defective construction of fire-place usually adopted for
puddling furnaces, is that the puddling or decarbonizing process is greatly interfered
with and deterioration of the quantity and quality of the yield is produced.
In the improved fire-place the hearth or dead plate is so inclined that the fuel
when fed in rests thereon at a natural slope in a layer of only moderate thickness
instead of at once' sliding down to the lower part of the fire-place and becoming piled
up in a thick ass on the grate bars. The coal when resting on this inclined
hearth is in a condition to be properly acted upon by the heat of the walls of the fire-
place, and will be completely distilled and in an uniform manner by the intense heat
evolved from the incandescent fuel on the small grate placed below it, as well as by
the heat reflected from the walls and roof when they are at a white heat. The com-
bustible gases, after distillation, are completely burnt or decomposed in the firo
chamber itself by the oxygen passing through the layer of incandescent fuel on the
grate, and therefore none but heated gases deprived of uncombined carbon can enter
the puddling or reheating chamber. The residuum of the distillation is composed of
pure coke, with a little slag or cinder, the former constituting the fuel by which.
(when it slips down on to the grate) the fresh coal thrown on to the inclined hearth
in the fire-place is to be distilled. This system of burning fuel may be likened to
a gas retort heated interiorly, with this difference, that the combustion of the gases
takes place upon the spot or in the chamber where they are produced. This is an
important characteristic of the improved fire-place or furnace, and distinguishes it
from the furnaces or fire-places heretofore employed for heating purposes.
As the coke when burning on the grate gives passage to very little more oxygen
than is needed for its own combustion there remains in the gases evolved from tho
fuel an excess of free carbonic oxyde and carburetted hydrogen, the result being that
when these gases are consumed in the fire-place, and a flame is thereby produced, it
will be a neutral flame, and the effect of such flame upon the metal to be worked or
treated in the furnace will be but slightly oxydizing.
More or less oxygen for assisting in the process of puddling iron may, however,
be supplied to the fire-place by increasing or diminishing the number of the fire-
bars of the grate, and thus enlarging or lessening the open spaces in the grate for
the admission of air through the fuel
As the fire-bricks which form the sides of the fire-place would be rapidly dete-
riorated by the great heat produced therein there may be formed in the walls on each
side of the fire-place or combustion chamber two corresponding horizontal conduits,
the one placed above the other: Three vertical conduits or air shafts are in com-
munication with the upper horizontal conduit. The cold air enters by the lower
conduits, and spreads within or passes along the others, and leaves the furnace by
the top or open ends of the vertical conduits, without passing into the interior of
the furnace. A constant current of cold air being thus kept up within these con-
duits, the walls of the furnace are thereby cooled and will last. much longer than
would otherwise be the case. The number and position of these air conduits or
flues may of course be varied if desired.
As an example of the adaptation of the improved fire-place to an useful purpose
in the arts, Fig. 1.in the accompanying Drawing is a longitudinal vertical section of
a puddling furnace, with the improved fire-place adapted thereto; Fig, 2 is a hori-

page_text: zontal, section or sectional plan view of the same; Fig. 3 is a transverse vertical
section taken through the fire-place in the line 1, 2, of Figures 1 and 2.
The puddling chamber A, with its hearth and roof, are of the ordinary construc-
tion, and therefore need not be minutely described, the present Invention being con-
fined to the construction of the fire-place or combustion chamber B, which (instead
of being made of shallow depth, and with a horizontal or nearly horizontal
hearth or sole plate and grate bars) is made of considerable depth below the top of
the fire-bridge a, so as to form a capacious combustion chamber, in which the gases
evolved or distilled from the fuel are decomposed, burned, and converted into flame
and hot incombustible gases. The fire-bars b are placed at a slight inclination, as
shewn at Figures 1 and 3, and are supported on triangular transverse bars b', b1
Above the grate b is placed the inclined hearth e, which is constructed of fire-
brick or other refractory material, resting on au inclined metal plate. The degree
of inclination of this hearth is important as upon it in a great measure depends the
proper working of the apparatus and the economical combustion of the fuel. The
outer ends of the fire-bars b extend under the lower end of the inclined hearth, a
narrow opening being left between them for the purpose of introducing an iron tool
for clearing or removing slag or cinder, which may from time to time adhere to the
fire-bars. At the upper end of the inclined hearth c is a plate d, on which the coal
or fuel is placed, a long narrow opening being left for the purpose of allowing the
fuel or coal which is thrown on to the plate d, to slide therefrom on to the inclined
hearth c, down which the coal slides on to the fire-bars b below, until it forms a
layer of about four inches thick on the inclined hearth. While this moderately thin
layer of coal is supported from below no more will slide down until the fuel on the
grate b is consumed. Ordinary bituminous coal, when introduced into the open-
ing will naturally lie on the inclined hearth to the depth of about four inches,
when the inclination of the hearth is about forty-five degrees. If the coal be highly
bituminous and soft the angle of inclination may be slightly greater than forty-five
degrees, but if the coal be of a dry or anthracite quality the angle of inclination
inay be somewhat less than forty-five degrees.
From the above it will be understood that the angle of inclination of the hearth
must depend in a great measure upon the character of the coal employed, the object
being to place the hearth at such an angle that the coal will naturally lie upon it to
the thickness or depth of about four inches when supported from below, but will
slip down to the lower part of the fire-place on to the grate b when the fuel on the
latter is burned away. It will be evident, therefore, that if the coal be of a dry
sort, such as anthracite coal, and the inclination of the hearth be too steep, the coal
will not remain on the hearth but will slip down on to the grate bars b, and will
forn a deep mass of fuel, which will generate gases in such quantities that they
cannot be economically consumed or decomposed in the fire-place itself for want of
a sufficient supply of oxygen through the grate bars. If, on the other hand, the
coal be highly bituminous, and the inclination of the hearth c be too little, the fuel
will not slip down by its own weight, and therefore must be pushed down by hand,
an operation which it is desirable to avoid as the object of the Invention is to make
the fire-place almost self-acting, so as to render it necessary simply to place the coal
on the plate d, push it over the opening d', and keep the grate bars b clear of slag or
coagulated cinder. If, therefore, the angle of inclination of the hearth c be
properly arranged a very slight touch with the stoking iron will be sufficient to
cause the exhausted coke on the inclined hearth to slip down on to the grate when
the fuel on the latter has been partly consumed. When the coke on the inclined
hearth slips down on to the fire-bars its place will be taken by the fresh coal which
is piled up above, and closes the opening in the plate d; the attendant will
therefore have little more to do than to throw the coal on to the plate d and keep
the opening a closed so as to exclude the air.
We would here remark that some kinds of coal are more apt to clinker than
others, and by so doing will form a compact, solid mass, which will interfere with

page_text: the draught through the fire-grate; part of the clinkers will also adhere to the fire-
bars. When coal of this character is used we find it advisable, from time to time,
to draw out the fire-bars, for the purpose of cleaning them and removing therefrom
the clinkers which adhere thereto, and also to allow the clinkers in the fire-place to
fall into the ash-pit below. In order to do this, without materially interfering with
the fire in the fire-place, a horizontal bearing bar 6 is adapted to the long slit or
opening at the bottom of the inclined hearth c, for the purpose of supporting a
wide bearing plato or grid which is to be thrust into the narrow slit or opening
beneath the buring fuel, but above the clinkers on the bars b, as shown at Fig. 1.
This bearing plate or grid should be about one third the width of the fire-place, and
when thrust in will extend from the inclined hearth c to the back wall of the fire-.
place, as hewn in Fig. 1, and will thus temporarily support the fuel, while those
fire-bars which are below it are withdrawn, for the purpose of removing the
clinkers therefrom and allowing the incombustible clinkers at the bottom of the fuel
to drop into the ash-pit below; when this has been done the fire-bars may be
replaced, and the wide bearing plate or grid may be drawn out and introduced
above another part of the grate, so that a further section of the grate bars may be
withdrawn and cleansed and the clinkers removed from the fire-place. By repeating
the operation all the bars may in turn be cleansed and all clinkers removed from
the grate, without unnecessarily disturbing the fuel in the fire-place or stopping the
action of the fire.
In order to keep the walls of the fire-place cool horizontal and vertical flues or
passages e, o, o, e, are constructed therein, as shown in Fig. 3 and by dots in
Figures 1 and 2. Air from the ash-pit or the space in front of the fire-placo
and beneath the inclined hearth centers the flucs or passages e, e, and after
traversing the horizontal and vertical flues escapes out at the top or open ends, as
indicated by the arrows in Figures 1 and 3, without passing into the interior of the
furnace.
Setting the fire-placo to work and feeding it with fuel are very simple operations,
but are widely different in effect from the plans usually adopted. The fire is laid
in the ordinary manner, by first placing wood upon the grate bars band a few
lumps of coal upon the wood. The feed opening d, which is of restricted size,
being then closed with lumps of coal the wood on the fire-grate b is lighted from
beneath. When the whole is alight the coal which has been used to stop the feed
opening d is allowed to run down the inclined hearth c and large and small coal (as it
comes to hand) is fed into the fire-place, until the inclined hearth c is covered with
a layer of coal about a hand thick; in other words, as much coal is allowed to pass
through the opening on to the inclined hearth as will naturally lie thereon, and
when the inclined hearth is thus charged with coal it will close the feed opening d
and prevent air from entering the fire-place through that aperture. In order that
this opening may be always kept closed as the distilling operation proceeds coal is
-piled up above it and on the plate d, so that, as the fuel burns away on the grate
and hearth, the coal may slip down without unclosing the opening; the fire is then
allowed to make head in the fire-place, and in about two hours the interior of the
fire-place will have come to a red heat. The coal first placed upon the grate will
then have been completely burnt, and that resting on the inclined hearth will have
been partially distilled; then by means of a poker or fire-iron of a suitable size
(passed through the feed opening d' or through the opening at the bottom of the
inclined hearth) the coke is stirred about and the calcined fuel on the inclined
hearth will slip down and be spread equally over the grato below, and the coal on
"the plate d is again fed into the fire-place, the feed opening d' being all the while
kept closed by coal on the plate d.
The use of a good and pure coal in this improved furnace gives a greater saving
than when inferior coal is used, but the economy of fuel in either case is very
considerable, and the application of this Invention to an ordinary puddling or
reheating furnace is very inexpensive, as but slight structural alterations are

page_text: required. The result of this improved construction of firo-place for puddling
furnaces is (as regards quantity of yield) at least equal to if not greater, and as
regards quality it is superior to that obtained with the ordinary furnaces, this latter
advantage being due to the elevation of the fire-bridge, which does not permit
impurities or uncombined carbon to reach the puddling chamber, as heretofore.
The economy of fuel is very great, as the gaseous products are burned under the
best possible conditions and in the most advantageous manner.
It will be evident that this improved construction of fire-place may be adapted
to reheating or annealing furnaces, or to glass, porcelain, and earthenware kilns and
furnaces, and to other purposes where a neutral flame or heat uncontaminated with
free carbon is required. It may also be employed for heating steam boilers or
evaporating pans. It will not however be necessary to show the furnace as applied
to these several uses, as its construction in all cases is much the same.
Having now described the Invention of "Improvements in Furnaces," and having
explained the manner of carrying the same into effect, we would observe that we
are aware that heretofore fire-places have been made with inclined sides and of con-
siderable depth and with a fire-grate at bottom to support the coal or fuel, but in
all these cases there has been a great depth of fuel in the fire-place or chamber, for
the purpose of generating combustible gases, which were either drawn off by
suitable pipes in order to be burned elsewhere, as in Siemens's furnace, or were
carried forward, together with a suitable supply of air obtained or drawn in through
convenient openings, in order that such gases and air may be burned in an adjoining
chamber, as in an ordinary puddling or reheating furnace. We are also aware that
puddling furnaces have been constructed with shallow fire-places having horizontal
hearths (instead of the ordinary fire or grate bars) nearly on a level with the hearth
of the puddling chamber, and air to support combustion has been admitted at the
front of the fire-place, as in coke ovens, but in this instance also the combustible
gases evolved from the conl have (together with the air to support the combustion
of the gases) been carried forward into the adjoining puddling or reheating chamber,
where they are burned. These fire-places however differ essentially in construction
and operation from the improved construction of furnace or fire-place above
described, inasmuch as by the present Invention the fire-place or chamber (in which
the combustible gases are evolved or distilled from the coal) constitutes the com-
bustion chamber, in which the gases are decomposed, burned, and converted into
flame or heat, all the carbon and hydrogen being thus decomposed and converted
into heat, which is carried forward into the puddling or reheating chamber in such
a chemical state as will effectually prevent them from acting injuriously on the
iron. For this reason the puddling process is in the improved furnace conducted
with greater facility and speed, and with more certainty than heretofore; at the
same time there is a very considerable economy of fuel, also an improvement in the
quality of the iron and an increase in the quantity produced; whereas, if the
undecomposed gases and air are allowed to pass into the puddling or reheating
chamber, as is now the case, the decarbonization of the iron will be delayed or
materially interfered with, thereby increasing the labour of puddling, the time
required for the operation, and consequently the expenditure of fuel.
In conclusion, we claim as the Invention secured to us by Letters Patent as
aforesaid, the arrangement, construction, and combination of parts herein shewn
and described (constituting a combined fire-place and combustion chamber) whereby
the combustible gases may be distilled or driven off from a thin layer of coal
resting on an inclined hearth, and may be burned or converted into flame in the
fire-place or combustion chamber itself, instead of being carried forward in an
undecomposed or unconsumed state into another or adjoining chamber where the
heat is intended to be utilized. We claim, particularly, the combination with a
fire-grate b (at the lower part of a deep chamber or fire-place B) of an inclined
hearth c placed at such an angle that the coal or fuel, which is fed in through a
long narrow opening at top, will naturally rest on the inclined hearth to the thick-

page_text: ness of about four inches, so that the combustible gases may be driven off or
distilled therefrom, as and for the purposes herein set forth, a sufficient supply of
air to support the combustion of the gases being allowed to pass through the incan-
descent fuck on the firo grate, as above described.
In witness whereof, I, the said James Harris Sanders, have hereunto set my
hand and seal, the Eighth day of November, in the year of our Lord One
thousand eight hundred and soventy-six.
J. HARRIS SANDERS. (L.S.)