CERTAIN IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF FURNACES OR FIRE-PLACES, APPLICABLE VARIOUS USEFUL PURPOSES
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULIUS
ADOLPII DETMOLD, of the City of London, Merchant, 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 Eighteenth day of October, in the seventh year of Her
reign, did, for Herself, er heirs and successors, give and grant unto me, the
said Julius Adolph Detmold, Her especial licence, full power, sole privilege
and authority, that I, the said Julius Adolph Detmold, my executors, adminis-
trators, and assigns, and such others as I, the said Julius Adolph Detmold, my
executors, administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times during the term of years therein
mentioned, should and lawfully might make, use, exercise, and vend, within
England, Wales, the Town of Berwick upon Tweed, and in all Her Majesty's
Colonies and Plantations abroad, and in the Island of Guernsey, Jersey,
Alderney, Sark, and Man, an Invention of "CERTAIN IMPROVEMENTS IN THE
CONSTRUCTION AND ARRANGEMENT OF FURNACES OR FIRE-PLACES, APPLICABLE
VARIOUS USEFUL PURPOSES," being a communication from a foreigner residing
abroad; in which said Letters Patent is contained a proviso obliging me, the
said Julius Adolph Detmold, by an instrument in writing under my hand and
seal, particularly to describe and ascertain the nature of the said Invention,

page_text: and in what manner the same is to be performed, and to cause the same to
be inrolled 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 thereunto had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Julius Adolph Detmold, do hereby declare the nature of the said Invention,
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, and Drawings therein referred
to and hereunto annexed, that is to say :-
In the furnaces employed in the different processes of the arts, and which
lepend for their supply of air for combustion upon the draught created
by a high stack or chimney, a large proportion of the fuel is converted into
combustible gases, which escape unconsumed out of the chimney at certain
times; also especially when the layer of fuel on the grate is very thin, a con-
siderable portion of atmospheric air passes undecomposed through the fire
grate into the furnace, which, in the reverberatory furnaces employed in
working metals, causes a portion of the metal that is worked in the furnace
to become oxydized or wasted. The formation of combustible gases in the
furnace, and the passing of undecomposed air through the grate, tend each of
them to lower the temperature of the furnace. In additon to this the cold or
outer air is being continually drawn into the furnace through the door when
open, and through every opening or crevice that may exist in the furnace, and
this also contributes to diminish the heat, while at the same time it increases
the waste of the metal by oxydation. Now to obviate these disadvantages,
I adopt the following constructions and arrangements:-Firstly, I make the
grate or fire chamber of my furnaces much deeper than the fire chamber or
grate of the furnaces now in general use, by which means I always have a
thick stratum of fuel upon the grate or fire bars, thereby preventing the
passage of undecomposed air through the grate into the interior of the furnace.
In ordinary furnaces the depth of the grate, that is, the distance between the
grate bars and the top of the fire bridge is generally from twelve to eighteen
inches, and seldom exceeds two feet; but in my improved furnaces the
depth of the grates is from three to five feet, according as the coal employed
is more or less bituminous. When a caking or highly butuminous coal is used
I make the grate not less than three feet in depth; for a free burning coal, four
feet in depth; but, for a very dry fuel, such as coke or anthracite coal, I find a
depth of five feet most advantageous. Secondly, instead of relying upon the draft
of a high chimney for the combustion of the fuel, I force the requisite supply of

page_text: air by means of any ordinary blowing machine under the great into the ash
pit, which is closed by an air-tight door; thus the blast will cause the com-
bustion of the lower stratum of coal immediately upon the grate, and the
greater portion of the gases resulting from this combustion will be a com-
bustible gas, namely, the carbonic oxide, which is invariably produced during
the process
of combustion when the temperature is very high, and when the
proportion of carbon is in excess to that of oxygen. The portion of carbonic
acid gas which is produced by the combustion of the lower stratum of fuel
immediately upon the fire bars will, in its passage upwards through the super-
incumbent mass of ignited coal, absorb an additional dose of carbon, and will
thereby also become converted into carbonic oxide. At the same time the
carbonaceous gases contained in the fuel, such as carburetted or bicarburetted
hydrogen, will be evolved or distilled from the coal by the heat. Thus all the
fuel in the fire chamber, (that is to say,) all that is combustible in the fuel, is
converted into combustible gases, which will pass together over the fire bridge
into the furnace. The body of fuel in the fire chamber, with the exception of
the stratum resting immediately upon the grate or fire bars, is never at a high
temperature, as is ordinarily the case in furnaces, but is kept only at a red
heat, which is quite sufficient to cause the formation of the combustible gases
from the fuel. Thirdly, I effect the combustion of these gases by forcing
amidst them in their passage over the fire bridge heated and compressed
atinospheric air, supplied in numerous small streams, thereby causing a rapid
and intimate combination of the oxygen of the air with the combustible gases,
and consequently their perfect and immediate combustion, and a most intense
temperature. The temperature of the compressed air may be regulated at
will by means of a damper connected with the apparatus for heating the air,
as will be hereafter described. The supply of blast (cold air) under the grate,
by which the combustible gases are generated and evolved from the fuel, and
the supply of the hot air for their combustion, is regulated by means of a cock
or valve, and must be adjusted to each other so as to effect the complete com-
bustion of all the carbonaceous matter in the gases, and prevent any passing
away. In the working of metals the effects of the flame in the furnace may
be made at will, either reducing the neutral or oxydizing according to the
quantity of combustible gases generated, or the volume of hot air admitted
into the furnace to promote their combustion. The requisite compression of
the air within the furnace, so that its pressure may always exceed that of the
atmosphere, is obtained by a register or damper or other contractor at or near
the top of the chimney. The heat thus produced from the fuel is also more
directly applied to the purposes required than in ordinary furnaces, in which

page_text: the heat is produced by the partial combustion of the fuel upon the grate,
and where the metals under operation derive their temperature merely from
the flame in its passage through the main or working chamber of the furnace,
whereas in my furnace the temperature of the fuel in the fire chamber where
the combustible gases are generated is comparatively low, and their actual
combustion and the intense temperature resulting therefrom is concentrated in
the very spot where the metals are placed for operation, or where the greatest
heat is required. The loss of fuel by the escape of combustible gases out of
the chimney is thus avoided, as also the diminution of temperature and the loss
of metal by oxydation from the effects of undecomposed air passing through
the grate, or through the working door, or any openings or crevices in the
furnace. As the combustion of the gases in the furnace is effected under a
greater pressure than that of the atmosphere without, any kind of coal or fuel
may be advantageously used in furnaces of this description, and stone coal
or anthracite, which cannot be successfully employed for metallurgical purposes
in reverberatory furnaces of the ordinary construction, will be found particu-
larly applicable and advantageous. Furnaces of this improved construction
may be employed with greatest advantage in the working of all kinds of metals,
but are of peculiar value in the different processes of the manufacture of iron.
The advantages are, first, a more intense temperature than is produced in
reverberatory furnaces now in general use. Second, an important saving of
fuel. Third, a better yield in the working of metals; or, in other words, a
diminished loss of metal from oxidation. For the purpose of explaining more
fully my improvements, I will now proceed to describe by reference to Drawings
the construction and arrangement of a furnace, which I have employed for the
refining or decarbonizing of iron, it being understood that the same construc-
tion and arrangements, with such variations as circumstances and the purposes
to which the furnace is to be applied will obviously require, are to be adopted
in other cases. Fig. 1 exhibits a plan or horizontal section of a refining furnace
for decarbonizing iron; Fig. 2, a longitudinal section, taken vertically; Fig. 3,
a front elevation; and Fig. 4, a transverse section, taken in the line 1, 2, of
Fig. 2, and shewing the arrangement of air heating pipes in the stack or
chimney. Fig. 5 is another transverse section, but taken in the line 3, 4, of
Fig. 2, and shewing the position of the tuyeres. Figures 6 and 7 represents
a plan and front view of the chainber with the hot air blast pipes or nozzles.
A is the fire chamber, built of fire brick, which may be about 4 to 5 feet in
depth and about three and a half to four feet square, which is filled with the
fuel from which the combustible gases are evolved and generated. B is the
grate upon which the fuel rests that is to be converted into gas. b, b, b, are

page_text: plates of cast iron about ten inches wide, which are laid upon the grate for the
purpose of protecting the sides of the fire chamber immediately above the grate
from being burnt, for the ashes of the fuel will rest upon these plates, as shewn
in the Drawing by the dotted lines, and being a non-conducting substance will
serve to keep the brickwork of the sides immediately above the grate from
being destroyed by the action of the fire. C is the ash pit, which has a door D
in front, by which it may be closed entirely. E is an opening in one of the
sides of the ash pit, through which atmospheric air is blown into the ash pit
by means of any ordinary blowing machine. F is the stoking hole for filling
the chamber A with fuel. G is a hot air chamber, which is placed on the top
of the gas generating chamber, and from which issue a row of nozzles or blast
pipes H, H, H, H, H, H, H, I, as more particularly shown in Figures 6 and 7;
the heated air is blown through the nozzles amidst the gases in their passage
over the fire bridge. As represented, there are nine of these nozzles, but a
greater or less number may be employed. They are made of sheet iron,
or any other suitable material, and about two inches diameter at the larger
end and one and a quarter inches at the mouth or smaller end, which is
slightly flattened, as shewn more particularly in Fig. 7. The hot air for the
combustion of the gases may be supplied also by allowing it to issue from
apertures of any dimensions in the sides of pipes, conduits, or other apparatus.
but is best effecting by forcing it amidst the combustible gases through a range
of twyers or nozzles, as above described. The fire bridge I, over which the
combustible gases and the streams of heated and compressed air becomic
mixed and combustion effected, is made longer than in ordinary reverbe
ratory furnaces for the purposes of affording the hot air and gases time to
become thoroughly combined before entering the main chamber of the furnace.
K, K, is the main chamber of the furnace, where the iron is refined or decar-
bonized. I. is the hearth or bottom, made of fire brick or fire sand; it is sup-
ported upon cast iron plates, the same as in ordinary puddling or heating
furnaces. M, M, are cast iron blocks that surround the whole hearth, and
through which a stream of cold water is made to circulate for the purpose of
protecting the sides from being destroyed by the intense heat of the melted
metal and scoria. N is the tapping hole, through which the refined metal is
run out from the furnace. O is an arch of fire-brick, which forms the top of
the gas generating chamber, and serves to protect the hot air chambers and
nozzles from the destructive action of the fire. The arrangement and protec-
tion of the hot air chamber and nozzles is of importance to be attended to in the
application of this apparatus. For this purpose I construct the above-named
arch of fire-brick, leaving the the pipes themselves exposed to the air, their

page_text: ends or mouths being inserted through a range of fire brick, and luted with
fire clay, as shewn at P, which connects the roof or top O of the fire chamber
with the roof or arch Q, Q, Q, that covers the furnace. R is the passage
through which the combustible gases pass from the fire chamber over the
bridge I into the main chamber K, K. S is the throat or flue of the furnace;
and T is the chimney or stack whence the burnt gases finally escape. U is the
chamber built of fire-brick, and in which an arrangement of pipes is placed
for the purpose of heating the air for the combustion of the gases and the
refining or decarbonizing of the iron. This chamber is separated from the
chimney by a partition, which has, however, numerous openings through
which sufficient heat is communicated to the pipes to heat the air which is
forced through them to the required temperature. I regulate the temperature
of the blast by causing more or less of the burnt gases to enter into the
chamber U through the openings g, 9, 9, 9, in the brick partition, which is
effected by means of a damper V, whereby the area of the passage or
chimney T or that of the chamber U may be diminished at will. By this
means I can cause the whole volume of the burnt gases or any portion thereof
to pass into the chamber U, thereby increasing the temperature of the blast
without interfering with the draft of the furnace. The air may be also heated
by forcing it through cast iron boxes or pipes placed around the earth of the
furnace in the place of the water blocks M, M, above described; this current
of air will at the same time serve to protect the sides from the action of the
heat. This arrangement is more particularly shewn in Fig 8 and 9, which
represent different views of a heating or balling furnace. Y is the working
door of the furnace, which is the same as in ordinary furnaces. W, W,
Figs 1 and 3, is a pipe leading from a blowing machine that supplies the
cold blast, from which a branch w goes off to furnish the cold blast under
the grate into the ash pit, and which is regulated by the valve æ. Another
branch w, Fig. 3, uses and communicates with the arrangement of pipe in
the chamber U. From thence the heated air is conveyed by the pipe w to
the hot air chamber G, where its supply is regulated by the valve a. Two
branches,, supply the hot air from the twyeres ¹,, which is also regu-
lated by the valves y, y. The mode of refining or decarbonizing iron in a
furnace of this kind is as follows:-The fire chamber A is filled with fuel, and
after it is ignited the cold blast is let on under the grate, and the combustible
gases are generated thereby, the ash pit being closed tight. The valve a is
then gradually opened to admit hot air for the combustion of the gases. After
the furnace has been brought to a white heat from twenty-five to thirty hundred-
weight of pig iron is charged and spread all over the hearth, piling it in such

page_text: a manner as to leave interstices for the flame to circulate well through.
When the charge is melted down quite thin the blast of hot air is let on
through the twyers z³, ¹, which being placed so that the lines of their axes
converge towards the middle of the hearth, and having a pitch of from
twenty-five to thirty degrees, will cause the liquid iron to move round in
two opposite currents, thereby exposing every part of the surface to the
decarbonizing influence of the blast. The refiner judges by trying the metal
with the bar, the same as in the open finery in general use, whether it be
sufficiently refined or decarbonized, which will generally be the case with a
charge of twenty-five hundredweight in about a hour after the blast is let on
through the twyers. The furnace is then tapped and the metal is run in a fluid
state into the mould, the same as in the ordinary process of refining in the open
finery, which is well understood. The process of refining may be hastened and
facilitated by adding to the charge of crude iron about one hundred weight or
more of finery cinder, which is made in the ordinary process of refining iron in
the open finery fire, and of which cinder there are generally large quantities on
hand at every iron works. But I do not find that the addition of this cinder
is necessary to effect the process of refining or decarbonizing. This mode of
refining affords a very important saving of iron over the ordinary mode of
refining in the open finery; for in the ordinary process the iron is exposed to
the oxydizing action of the blast from the twyers during the whole period of
its melting down, so that a very large proportion of the iron is actually con-
verted into cinder by the blast before the whole charge is fused. The loss of
iron in the open finery varies from twelve to fifteen per cent., but in the operation
of refining in the improved furnace the whole charge of iron is melted down
without loss from oxydation, as no more air is allowed to enter the furnace than
what is required for the combustion of the gases, and the process of decarboniza-
tion does not commence until the iron is all melted down. The loss of iron,
therefore, in the process of refining in my furnaces is much reduced, and rarely
exceeds seven per cent., varying generally from five to seven per cent. Another
advantage derived from this mode of refining is that raw coal may be used,
whereas the open finery requires the coal to be coked. The quantity of coal
necessary to refine a ton of iron in these improved furnaces is from six to seven
hundredweight. This kind of furnace may with the greatest advantage be
employed in puddling pig or crude iron, instead of refined metal, by combining
the two processes in the same furnace, whereby a very great saving of fuel and
ron as well as labour will be produced. When employed for puddling I make
he hearth about eighteen inches wider than that of the refinery furnace above
lescribed. The furnace has two doors opposite to each other, at each of which

page_text: a puddler works. About nine hundredweight of pig iron is charged, which
after being melted down in the manner before described, is subjected in the
same manner as above described to the decarbonizing influence of streams of
hot air from the twyers ¹, 21. After the iron is sufficiently refined the hot blast
is shut off from the twyers 1, . The cinder or scoria which has been formed,
and which floats on top of the iron, is then drawn off through the working doors
by means of rables, or it may remain in the furnace until the balls are drawn
out, and then run out through the tapping hole, and the temperature of the
furnace is slightly lowered by partially closing the valve a, which admits the
blast under the grate, thus diminishing the quantity of combustible gases to be
generated in the chamber A, admitting at the same time as much hot air through
the nozzles II, H, as before, thereby rendering the flame slightly oxydizing.
The mode of regulating the temperature of the furnace during the different
stages of the process of puddling is well understood by workmen, it being
effected in the ordinary puddling furnaces by feeding the fire on the grate, and
lowering or raising the damper of the chimney. The puddler then commences
to puddle and ball up, which operation is performed in precisely the same manner
as in the ordinary puddling furnace when refined metal is worked, and which
is well understood. Fig. 8 is a longitudinal section; Fig. 9, a horizontal
section; and Fig. 10, a cross or transverse section of a heating, or balling, or
mill furnace. It differs in its general arrangement but little from the refining
and puddling furnaces above described. The Drawings will sufficiently explain
the difference without further detailed description. The hearth is made of a
thick layer of fire sand, the same as in the ordinary heating furnaces. The air
for the combustion of the gases is heated by causing it to pass through the cast
iron boxes a, a, a, which also tend to protect the sides of the furnaces from the
intense heat, as seen by dots in the plan view, from whence it is led by the pipe b, b,
which is built up in the walls of the furnace to the hot air chamber G. The
cinder runs off through the hole c. to which it is conducted by a channel made
in the back of the sand bottom. In conclusion, 1 desire it to be understood
that I do not claim as of the Invention communicated to me or the exclusive
use of the various apparatus or the several parts employed in the construction
and arrangement of the furnaces above described and referred to, when the
said apparatus and parts are taken separately, or except when the same are
used for the purposes of the said improvements. And I hereby declare the
said Invention to consist in a furnace so constructed and arranged as to generate
combustible gases in a close chamber by a blast or current of air forced through
a thick stratum of fuel, the combustible gases so generated being burnt under
a pressure greater than that of the external atmosphere by means of heated and

page_text: compressed air injected in streams into the combustible gases at the bridge of
the furnace, or near the point at which the heat of the furnace is required to be
applied.
In witness whereof, 1, the said Julius Adolph Detmold, have hereunto set
my hand and scal, this Eighteenth day of April, in the year of our Lord
One thousand eight hundred and forty-four.
Inrolled the same Eighteenth day of April, in the year above written.