IMPROVEMENTS IN THE CONSTRUCTION AND MODE OF WORKING FURNACES AND APPARATUS EMPLOYED IN FUSING MALLEABLE OR WROUGHT IRON AND STEEL, AND PIG OR OTHER CARBURETS OF IRON, AND OBTAINING CAST STEEL OR HOMOGENEOUS MALLEABLE IRON THEREFROM
Year: 1869

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS
IN THE CONSTRUCTION AND MODE OF WORKING FURNACES AND APPARATUS
EMPLOYED IN FUSING MALLEABLE OR WROUGHT IRON AND STEEL, AND PIG
OR OTHER CARBURETS OF IRON, AND OBTAINING CAST STEEL OR HOMOGENEOUS
MALLEABLE IRON THEREFROM."
Sealed the 6th July 1869, and dated the 10th May 1869.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the
10th May 1869.
I, HENRY BESSEMER, of Queen Street Place, Cannon Street, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION AND MODE OF WORKING FURNACES AND
APPARATUS EMPLOYED IN FUSING MALLEABLE OR WROUGHT IRON AND STEEL, AND
PIG OR OTHER CARBURETS OF IRON, AND OBTAINING CAST STEEL OR HOMOGENEOUS
MALLEABLE IRON THEREFROM," to be as follows:-
This Invention consists, firstly, in fusing malleable or wrought iron
and steel and also pig or other carburets of iron in furnaces where the

page_text: gaseous products of combustion within the said furnaces are retained
under a pressure much greater than that of the external atmosphere, but
which gaseous products are not greatly in excess of the pressure of the
atmosphere which immediately surrounds the exterior of the furnace
or some parts thereof, the difference being only such as will cause a
powerful draught or current of air to pass through the fuel in such
furnaces. For this purpose I employ both the cupola and the rever-
beratory form of furnaces constructed in the usual manner, except in so
far as they require to be modified to suit the conditions under which
they are employed in carrying out my Invention. These furnaces are
erected in the interior of a strong close iron room or chamber, the iron
casing extending beneath the floor of the room having all its joints
rendered sound and tight. These furnaces are provided with an outlet
for the escape of the gaseous products of combustion exterior to the close
chamber, the outlet being so small as to prevent the free, escape of the
gaseous products of combustion and retain the same within the furnace.
until the pressure is much in excess of the external atmosphere in a
similar manner to that fully set forth in the Specification of a Patent
granted to me, and bearing date the 10th day of November 1868, and
numbered 3419. The air. to support combustion in these high-pressure
furnaces is forced by a powerful blast engine, into, the close chamber in
which the furnaces are erected. I prefer to introduce it through numerous
small openings in a diffused state. The tapping holes or other discharge
openings of these furnaces may be made to open externally to the close
chamber, and in some cases the feeding doors may also be made to
open outwardly or be accessible from the outside of the close chamber,
or the tapping or discharge openings may open direct into the chamber,
and in cupola furnaces the upper part may in some cases pass through
the roof or crown of the close chamber and be fed from an elevated
feeding stage exterior to it, the mouth of the furnace being closed by a
strong well-fitting door or cover to prevent the escape of gases.
In constructing these iron rooms or chambers I give the necessary.
strength and stiffness to them by means of suitable angle flanges, ribs,
or girders, to which the plating. of the shell is rivetted, and I provide a
double iron door with well-fitted metallic faces or joints, or with joints
covered with vulcanized rubber or other suitable material, the inner door
opening into the chamber and the outer one opening into the external
atmosphere, a space being enclosed between the doors forming a sort of

page_text: small anti-chamber into which the workinen enter, and having shut them-
selves in they admit air under pressure from the chamber or blast pipe
until the pressure of the atmosphere in the small anti-chamber is equal to
the pressure in the large one, when the inner door may be readily opened
without stopping the blast. In coming out, the workmen after closing
the inner door opens a stop-cock by which the compressed air in the small
anti-chamber escapes into the external atmosphere until the pressures are
equalized, when the outer door will readily open. I prefer that the cock
or valve thus used by the workmen should be made so small that the
change of pressure may take place slowly and regularly, and thus not
subject the men to violent changes in the pressure of the air surrounding
them. The air by compression with the blast engine is increased in
temperature, and if a pressure of two or three atmospheres are used the
temperature of the air would be too great for the men to endure. I
therefore in all cases prefer to cool the air before it enters into the iron
room or chamber. For this purpose the air is forced through numerous
small tubes immersed in a tank of cold water or having a shower of cold
water falling upon them. I prefer to compress the air by the blast engine
to a greater extent than is required for the furnace, in which case the
air after being cooled may be allowed to expand again to some extent on
entering the iron room, such expansion further reducing the temperature
even, if desired, below, that of the external atmosphere. When the metal
is to be tapped from the furnace in the interior of the chamber I provide.
a door through which a ladle suspended from or mounted on a crane
may enter for the purpose of receiving the metal and conveying it away
to be cast in moulds, or I provide a door opening down to the floor level,
and I employ a truck on which a casting ladle is mounted; this truck
runs on rails through the door last named and receives the metal in
the ladle carried by it. Outside the chamber I make a sunk trench
between the rails on which the truck moves. This sunk trench forms a
casting pit. The moulds into which the fluid metal is to be run aro
placed in a line in this casting pit, and as the truck is moved over each
one in succession it may be filled with fluid metal from the ladle
by employing the valve arrangement generally employed in casting
Bessemer steel. The same arrangement for moving the ladle may be
used for casting when tapping the furnace from the exterior of the
chamber, or the ladle may be carried on a crane arm and the moulds be
placed in a semicircle, as in the Bessemer process of casting steel ingots.
The door by which the casting ladle is taken into the chamber I prefer

page_text: to slide against faced surfaces on the inside of the chamber. The rail
track may also be employed to convey fuel or metal to the interior of
the chamber when the materials are not supplied to the furnace from
doors formed in it opening externally. I fit a large safety valve to the
chamber by means of which the pressure of the air therein may be
limited to the amount desired; it may be constructed with a handle as
to allow the workmen to let down the pressure to that of the external
atmosphere if desired. I prefer to make this a double valve almost in
equilibrium. A sluice in the blast pipe accessible to the workmen inside
the chamber will allow him to regulate the admission of blast or shut it
off when desired. I also place a mercurial glass guage inside the chamber
to indicate at all times the internal. pressure of the air, and in the sides
or on the top of the chamber I make one or more openings for the
admission of daylight through stout plate glass. The iron frame of the
window I face truly, allowing the glass to bear on the several compart-
ments into which the frame is divided, and in which it is fitted air-tight;
or I otherwise frame a number of smaller pieces together. These
windows may be made the means also of admitting gas or other artificial
light or in lieu thereof lamps similar to those used in railway carriages
may be employed; or I have not herein particularly described the oil
or other lamps or candles may be employed in the interior of the chamber,
general details of the furnaces employed, nor the kinds of fuel or
mixtures of fuel used therein, nor the very many varieties of iron known
in commerce and included under the general heads recited in the title of
my said Invention; but I desire it to be understood that any of the
forms or modifications of furnaces shewn and described in the Patent
granted to me on the 10th day of November 1868, and numbered 3419,
may be employed with such alterations as the use of such furnaces in a
close chamber may render necessary or desirable; so also the several
modifications of reverbrating and other furnaces set forth in a prior
Specification, bearing even date herewith, "for Improvements in the
Manufacture of Malleable Iron and Steel, and in Furnaces and Appa-
ratus Employed for their Fusion and Treatment," may be used, all such
furnaces being so modified as to render them suitable for use in the close
room or chamber, and which alterations consist chiefly in dispensing
with the strong external shell of the furnace and the closely-fitting fire-
doors used in my former Invention. I desire it also to be understood
that the different kinds or qualities of malleable or wrought iron and
steel or other carburets of iron enumerated in the before-named Patent

page_text: of the 10th day of November 1868 may be employed for the production
of cast steel or homogeneous malleable iron by means of my present
Invention, using for this purpose the fuel or mixtures of fuel set forth in
either or both of the Patents herein-before referred to.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent Office
on the 10th November 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, Cannon Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of May, in the year of our
Lord One thousand eight hundred and sixty-nine, in the thirty-second
year of Her reign, did, for Herself, Her heirs and successors, givé and
grant unto ine, the said Henry Bessemer, Her special licence that I,
the said Henry Bessemer, my executors, administrators, and assigns, or
such others as I, the said Henry Bessemer, my executors, administrators,
and 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 "IMPROVEMENTS IN THE CONSTRUCTION
AND MODE OF WORKING FURNACES AND APPARATUS EMPLOYED IN FUSING MAL-
LEABLE OR WROUGHT IRON AND STEEL, AND PIG OR OTHER CARBURETS OF IRON,
AND OBTAINING CAST STEEL OR HOMOGENEOUS MALLEABLE IRON THEREPROM,"
upon the condition (amongst others) that I, the said Henry Bessemer,
my executors or administrators, 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 Henry Bessemer, do hereby declare
the nature of the said Invention, and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by the
following statement, thereof, that is to say: -
This Invention consists, firstly, in fusing malleable or wrought iron
and steel and also pig or other carburets of iron in furnaces where
the gascous products of combustion within the said furnaces are retained
under a pressure much greater than that of the external atmosphere, but
which gaseous products are not in excess but somewhat less than the
pressure of the atmosphere which immediately surrounds the exterior
of the furnace or some parts thereof, the difference being only such
as will cause a powerful draught or current of air to pass through the
fucl in such furnaces.
For this purpose I employ both the cupola and the reverberatory
form of furnaces constructed in the usual manner except in so far as
they require to be modified to suit the conditions under which they
are employed in carrying out my Invention. These furnaces are erected
in the interior of a strong close iron room or chamber, the iron casing
extending beneath the floor of the room having all its joints rendered
sound and tight. These furnaces are provided with an outlet for the
escape of the gaseous products of combustion exterior to the close
chamber, the outlet being so small as to prevent the free escape of
the gaseous products of combustion and retain the same within the
furnace until the pressure is much in excess of the external atmosphere
in a similar manner to that fully set forth in the Specification of a
Patent granted to me, and bearing date the 10th day of November 1868,
and numbered 3419. The air to support combustion in these high
pressure furnaces is forced by a powerful blast engine into the closc
chamber in which the furnaces are erected. I prefer to introduce it
through numerous small openings in a diffused state. The tapping
holes or other discharge openings of these furnaces may be made to
open externally to the close chamber, and in some cases the feeding
doors may also be made to open outwardly or be accessible from the
outside of the close chamber, or the tapping or discharge openings
may open direct into the chamber, and in cupola furnaces the upper
part may in some cases pass through the roof or crown of the close
chamber and be fed from an 'elevated feeding stage exterior to it,
the mouth of the furnace being closed by a strong well fitting door or
cover to prevent the escape of gases.
In constructing these iron rooms or chambers I give the necessary

page_text: strength and stiffness to them by means of suitable angle flanges, ribs,
or girders to which the plating of the shell is rivetted, and I provide
a double iron door with well fitted metallic faces or joints or with
joints covered with vulcanized rubber or other suitable material, the
inner door opening into the chamber and the outer one opening into
the external atmosphere, a space being enclosed between the doors,
forming a sort of small ante-chamber into which the workmen enter,
and having shut themselves in they admit air under pressure from
the chamber or blast pipe until the pressure of the atmosphere in the
small ante-chamber is equal to the pressure in the large one, when the
inner door may be readily opened without stopping the blast. In coming
out the workman after closing the inner door opens a stop-cock by
which the compressed air in the small ante-chamber escapes into the
external atmosphere until the pressures are equalized, when the outer.
door will readily open. I prefer that the cock or valve thus used
by the workmen should be made so small that the change of pressure
may take place slowly and regularly, and thus not subject the men
to violent changes in the pressure of the air surrounding them. The air
by compression with the blast engine is increased in temperature, and
if a pressure of two or three atmospheres is used the temperature of
the air would be too great for the men to endure. I therefore in all
cases prefer to cool the air before it enters into the iron room or chamber
For this purpose the air is forced through numerous small tubes
immersed in a tank of cold water or having a shower of cold water
falling upon them. I prefer to compress the air by the blast engine
to a greater extent than is required for the furnace, in which case
the air after being cooled may be allowed to expand again to some extent
on entering the iron room, such expansion further reducing the tem-
perature even if desired below that of the external atmosphere. When
the metal is to be tapped from the furnace in the interior of the
chamber I provide a door through which a ladle suspended from or
mounted on a crane may enter for the purpose of receiving the metal
and conveying it away to be cast in moulds, or I provide a door
opening down to the floor level, and I employ a truck on which a
casting ladle is mounted. This truck runs on rails through the door
last named and receives the metal in the ladle carried by it. Outside
the chamber I make a sunk trench between the rails on which the
truck moves. This sunk trench forms a casting pit. The moulds into
which the fluid metal is to be run are placed in a line in this casting.

page_text: pit, and as the truck is moved over each one in succession it may be
filled with fluid metal from the ladle by employing the valve
arrangement generally employed in casting Bessemer steel. The
same arrangement for moving the ladle may be used for casting when
tapping the furnace from the exterior of the chamber, or the ladle
may be carried on a crane arm and the moulds be placed in a semicircle
as in the Bessemer process of casting steel ingots. The door by
which the casting ladle is taken into the chamber I prefer to slide
against faced surfaces on the inside of the chamber. The rails may
also be employed to convey fuel or metal to the interior of the chamber
when these materials are not supplied to the furnace from doors formed
in it opening externally. I fit a large safety valve to the chamber,
by means of which the pressure of the air therein may be limited to
the amount desired. It may be constructed with a handle so as to
allow the workmen to let down the pressure to that of the external
atmosphere if desired. I prefer to make this a double valve almost
in equilibrium. A sluice in the blast pipe accessible to the workmen
inside the chamber will allow them to regulate the admission of blast
or shut it off when desired. I also place a mercurial glass gauge inside
the chamber to indicate at all times the internal pressure of the air, and
in the sides or on the top of the chamber I make one or more openings
for the admission of daylight through stout plate glass. The iron frame
of the window I face truly, allowing the glass to bear on the several
compartments into which the frame is divided, and into which it is fitted
air-tight; or I otherwise frame a number of smaller pieces together.
These windows may be made the means also of admitting gas or
other artificial light, or in lieu thereof lamps similar to those used in
railway carriages may be employed, or oil, or other lamps, or candles
may be employed in the interior of the chamber.
I have not herein particularly described the general details of the
several kinds of furnaces that may be employed, nor the kinds of
fuel or mixture of fuel used therein, nor the very many varieties of
iron known in commence and included under the general heads recited
in the title of my said Invention, but I desire it to be understood that
any of the forms or modifications of furnaces shown and described
in the Patent granted to me on the 10th day of November 1868, and
numbered 3419, may be employed with such alterations as the use
of such furnaces in a close chamber may render necessary or desirable.

page_text: So also the several modifications of reverberatory and other furnaces
set forth in a Specification bearing even date herewith (for Im-
provements in the Manufacture of Malleable Iron and Steel and in
Furnaces and Apparatus employed for their Fusion and Treatment,")
may be used, all such furnaces being so modified as to render them
suitable for use in the close room or chamber, and which alterations
consist chiefly in dispensing with the strong external shell of the
furnace and the closely fitting fire doors used in my former Invention.
And in order that this mode of constructing furnaces and apparatus
employed for the fusion of malleable iron and steel may be readily
understood I have shewn the same as applied to cupola furnaces on
Sheet A. of the annexed Drawings, where Figure 1 is a vertical section
on the line A, B, of Figure 2; and Figure 2, a horizontal section on
the line C, D, of Figure 1; Figure 3, a vertical section of the air
cooling apparatus; and Figure 4, a horizontal section of the same.
The same letters are used in all the Figures and indicate the same parts
where repeated.
a is the outer shell of the close chamber a'. The shell is composed
of well rivetted iron or steel plates strengthened by T-angle ribs a²
extending across its upper and lower sides, which are curved in order
better to resist the internal pressure, and are also further secured by a
central tension rod c having large flanged ends c*, which are firmly
bolted both to the top and bottom of the chamber. The lower curved
part of the chamber is filled in with brickwork 6 forming a flat floor to
the interior. Near to one side of the chamber a cupola furnace is erected
having an iron shell d lined with fire-brick e; this cupola passes through
the top of the chamber a¹. Around the upper part of the cupola is
formed a feeding stage, the floor of which is in part shown at f. The
materials to be fused and the fuel employed for that purpose are put into
the cupola at the opening g. In most cases it will be found convenient
to charge on at one time all the fuel and the metal forming one charge,
and then to close the feeding hole by a fire tile h, which is fitted into a
frame i, through which the cottered studs j pass. These studs are
screwed to the flanged ring of iron ke rivetted to the dome or upper part
of the cupola, the metal surfaces coming in contact being first smeared
with a luting of clay or lime to render the joint air-tight, or in lieu of
this mode of closing the mouth of the cupola it may be effected by a
compound screw apparatus, such as is shown and described as applied to

page_text: a cupola furnace in a Patent granted to me and bearing date the 10th
day of November 1868, and numbered 3419. The lower part of the
interior of the cupola furnace slopes down to the tapping hole n and
spout m, which projects through one side of the close chamber a', the
outer shell of which at this part is curved inward at an angle, as shewn
at 3, thus affording ready access to the tapping hole, and the larger
opening usually provided for cleaning out the furnace which is secured
by the iron plate 1. At p are openings leading from the interior of the
chamber a¹ into the cupola furnace, serving as tuyeres and admitting as
much air under pressure as can pass through the flue therein contained.
The rate of combustion and the pressure of the heated gaseous products is
regulated by the size of the opening which is formed in a well burned
lump of fire-clay, and securely held in place; the area of this opening
may be about one square inch for every square foot area of the hearth or
bottom of the cupola, but this will depend somewhat on the pressure of
air in the chamber a'. The workman can watch the operations going on
in the interior of the furnace through the openings p and can keep them
clear of slag from time to time. Light is admitted by day through the
stout plate glass window q, the glass is firmly embedded in a strong
iron frames, and at night by means of the gas lamp t, which is fitted
air-tight through the top of the chamber a', and is supplied with air
from the external atmosphere. Means of ingress and egress is provided
for the workmen at u, which is a close rivetted iron box or ante-chamber
having two well-fitted doors and w, the door frames against which
they close being covered with vulcanized rubber, and thus forming large
valves through which a man may readily pass. The door being in the
position shewn, the workman by further opening it may step from the
chamber a¹ into the box n, and after closing the door will open the
small two-way cock x, by which means the compressed air in the box u
will escape at y into the external atmosphere. So soon as the pressure
is thus equalized he will open the door wo and step out, leaving this door
open. On his desire again to enter the chamber a' he will step again
into the box u unless the door we should have been closed, in which case
a small amount of leakage of air through the door will prevent his
opening it. He must therefore allow the air to escape therefrom by
opening the cock z; he will thus be enabled to enter the box u. He
will then close the door w after him and open the cock x, so as to admit
air by the pipe A from the chamber a¹. As soon as the pressures thus
become equalized he can readily open the door and pass into the

page_text: chamber a. The pressure of the air in the chamber a will be indicated
by a mercurial gauge B, the cistern of mercury being open to the
chamber a and the upper end of the glass tube communicating with the
external atmosphere. The rate of admission of the air to the chamber a¹
and its consequent pressure inay be regulated or shut off by means of
the valve C, the discharge pipe D of which rises nearly to the top of the
chamber, and is provided with a large hollow disc D* perforated with
numerous small holes around its edge for the purpose of diffusing the
blast and preventing the inconvenience of a powerful jet at a particular
spot. Should the workman desire at any time to discharge the air from
the chamber a¹ he can do so by raising the handle E, which will raise a
valve in the valve box F, allowing the compressed air to escape into the
external atmosphere. A safety valve (not shown) should also be placed
on the chamber a¹ or on the blast pipe G to prevent the pressure of air
in the chamber from at any time exceeding the pressure desired, and
which may by preference range from 15 to 30 lbs. pressure on the square
inch, although this may be exceeded. A pressure as low as 6 to 7 lbs.
per square inch will assist the fusion of the metal but does not give
satisfactory results, and a pressure not exceeding 3 lbs. per square inch
is of little or no practical utility. When working under a pressure of
from 20 to 30 lbs. per square inch or upwards in the chamber a' the high
temperature produced by the compression of the atmosphere renders it
unbearable to the workmen employed unless some mode is adopted to
lower the temperature of the air supplied to the chamber. For this
purpose I employ the cooling apparatus shewn in section at Figures 3
and 4, and which consists of a square vertical box or chamber H, having
a separate compartment H' at top and another compartment H* at
bottom. The central space between these compartments is divided by
the partitions H3 and H', through which numerous small brass pipes pass
vertically upward from the compartment H* into the compartment E'.
The whole of the brass tubes have open ends, and arc rivetted or caulked
air-tight into the upper and lower tube plates J, J. Cold water from an
elevated reservoir enters the apparatus by the pipe K, and passes upward
between the brass pipes and over the top of the partition H; it then
descends in the central space between the partitions H and H', passing
under the latter, and again descends and passes off by the pipe L, following
the route indicated by arrows, and coming in contact throughout its
course with the exterior of the brass pipes before named. The air under
pressure from the blast engine enters the cooling apparatus by the

page_text: pipe M, and passes downwards through the numerous small brass pipes
into the lower compartment H', from which it ascends through the brass
pipes which occupy the space between the partitions H3 and H*, and
enters the upper compartment H', from which it descends again through
small brass pipes, and passes into the pipe G, by which it is conveyed into
the chamber a', having parted with much of its heat to the current of
water traversing the the exterior of the series of brass pipes in an opposite
direction to that in which the air is moving. By partially closing the
valve C in the chamber a' the pressure of the air will be increased
(provided that sufficient force is employed to compress the blast), the air
will consequently be raised in temperature, but as a large portion of the
cat so rendered sensible will be carried off by the water the air after
passing the valve C will expand on entering the chamber a¹ and become
sufficiently cool for the workmen employed therein. A pressure of
about 40 lbs. per square inch in the cooling apparatus expanding to
about 30 lbs. pressure in the chamber a¹ will render the air cool and
agrecable.
And in order that the mode of arranging reverberatory melting
furnaces (working under pressure in a close chamber) and the casting
apparatus connected therewith may be fully understood, I have shewn
how the same may be arranged and worked on Sheet B. of the Drawings
hereunto annexed, where Figure 1 is a vertical longitudinal section on
the line A, B, of Figure 2; Figure 2 is a horizontal section through the
close chamber, shewing the furnace, casting pit, and moulds in plan;
Figure 3 is a vertical section of the furnace and chamber on the
line C, D, of Figure 2, and Figures 4 and 5 are cross and horizontal
sections of the air cooling apparatus before described. All letters of
reference on this Sheet of Drawings indicate parts constructed and
arranged in the same manner and for the same purposes as those hercin-
before described in reference to the apparatus on Sheet A, and the parts
peculiar to the present arrangement of reverberatory furnace and
casting apparatus being indicated by numbers only, thus it will be
understood that the chamber a' with its strengthening ribs a, window q,
valves C and F, inlet pipe D and perforated disc D*, and the entire
arrangement of ingress and egress doors and w and box w, and the
entire details and arrangement of cooling pipes and apparatus as shewn
at Figures 4 and 5 on Sheet A are also the same in construction and
are used for the same purposes with the reverberatory furnace and
casting apparatus herein lastly shewn and described.

page_text: I will now proceed to describe those parts of the furnace and
apparatus which differ from the arrangements shown on Sheet B. and
which constitute the peculiarities of this modification of my Invention.
The furnace is of the reverberatory kind, encased with cast-iron plates 1
and binders 2 as usual in this class of furnace, the hearth 3 is nearly
flat, sloping a little towards the tap hole and spout 4, the piles or loose
pieces of iron or steel to be fused may be introduced at a door 5 at
the side of the hearth nearly opposite to the tap hole, or the metal may
be supplied to such furnaces by a suitable door formed at 6 where the
escape opening is now shewn, or in lieu thereof two moveable flue tubes
may be employed and be constructed in the manner represented on
Sheet C. of the Drawings annexed to the Specification of a Patent
granted to me and bearing even date herewith, and numbered 1431, so
that the reverberatory furnace in the close chamber a' may be worked
by simple chimney draught at the early stages of the fusing operations,
the final heat or fusing point being obtained by the employment of
high-pressure blast retained therein. I however desire it to be understood
that I do not claim the use of a double moveable flue tube as forming
part of the present Invention, although it may be employed in connection
therewith, when however the moveable flue tubes are not used I prefer
to employ a fixed restricted outlet, as shown at 6, which represents a
piece of burned fire-clay of a conical form fitted and luted into the
flanged ring 7, at this end of the furnace a ring 8 is formed having a
hollow channel in which water circulates in order to keep the contiguous
parts of the ironwork from becoming overheated, the hearth of the
furnace narrows at 3* and terminates in a circular opening of sufficient
size to admit the introduction of a charge of water through it, if desired,
by removing the flanged ring 7, which is held in place by cotter bolts
as shown; the fire-bars are shewn at 9 resting on bearers, which cross
the ash-pit 10, the ash-pit being open as usual in such furnaces. Fuel
is supplied to the fire-grate through the door 11 from the interior of the
close chamber, it will nevertheless be obvious that by placing the
furnace sufficiently near to the side of the chamber that the fuel may
be supplied through a sliding door from the exterior of the chamber,
but I prefer to supply it from the interior as described. On the outside
of the chamber a' a long narrow pit 12 is formed, having an angled
curve 13 forming a rail for the wheels of the ladle carriage to move
this carriage is fitted at one end with a casting ladle 15 having
a yalve and handle (not shown) after the manner of the ordinary casting
on;

page_text: ladles employed in casting Bessemer steel; a counterweight 16 rests on
the opposite end of the carriage and prevents the weight of the metal
in the ladle from tipping the carriage over. A door 17 is fitted as a
dovetailed slide moving vertically; a rod 18 attached to the door passes
through a stuffing box 19, and is shewn broken off; the upper end of
this rod may be attached to a rack or screw for lifting the door, but
I prefer to fasten to it a wire rope which may pass over a pulley
attached to the roof of the building, and have a balance weight attached,
so that the sliding door 17 may be run up and down by hand. When
the metal in the furnace is fused the workman proceeds to close the
tap hole and allow the metal to run by the spout 4 into the ladle, he
will then push the carriage along the rails until the running out hole 24h
of the ladle is vertically over the first of a series of moulds 20, which
he will fill and "stopper" in the usual way, proceeding to the next
and so on until all the metal is. run from the ladle, the carriage and
ladle is shewn by dots at 15* in the position it occupies while the
casting operation is going on, after which it may be rolled on a con-
tinuation of the rails and the ladle be lifted by crane from the carriage
and turned upside down, so as to discharge the scoria, if needful, or if
preferred the ladle may be mounted on trunnions as usual in the casting
cranes in general use for casting Bessemer steel, and be turned over
and the slags discharged therefrom; the line of rails at the side of the
casting pit may also be employed to convey an empty truck into which
the moulds and ingots may be lifted and taken away.
I desire it also to be understood that the different kinds, or qualities
of malleable or wrought iron and steel, or other carburets of iron
enumerated in the before-named Patent of the 10th day of November
1868, may be employed for the production of cast steel or homogeneous
malleable iron by means of my present Invention, using for this purpose
the fuel or mixtures of fuel set forth in either or both of the Patents
herein-before referred to.
I would further remark that in the production of malleable iron
or steel by the use of high-pressure furnaces enclosed within a strong
chamber as herein described, I am enabled to attain so high a tempera-
ture as to fuse these refractory substances with great facility, and give
to the metal so melted such a degree of heat as to admit of its being
transferred to several moulds while still retaining its fluid state; but
it will be understood that such furnaces are not applicable for the

page_text: fusion of substances where the heat of an ordinary furnace is or has
been found sufficient to produce fusion, because all such ordinary
furnaces are worked with greater facility by the workmen, are less costly
to construct, consume less fuel, and also require much less engine power
than the apparatus constituting my present Invention. I therefore do
not claim its use for simply heating iron bars or for melting pig iron,
the special use and value of my improved apparatus being the fusion
of malleable iron, decarburized iron, or uncarburized or spongy iron, or
steel or steely iron, such qualities or kinds of iron or steel in the form
of scrap or otherwise being used alone or mixed with as much spiegel
eisen or other carburet of iron as may be found desirable in the manu-
facture of malleable iron and steel by means of the said apparatus.
Having described my Invention, and the manner in which the same
may be carried into practical operation, I desire it to be understood that
I do not confine myself to the precise details herein described, provided
that the general character of my Invention be retained, but what I do
claim as my improvements in the construction and mode of working
furnaces and apparatus employed in fusing malleable or wrought iron
and steel and pig or other carburets of iron, and obtaining cast steel
or homogeneous malleable iron or steel therefrom is,―
Firstly. The employment for the fusion of scrap or other decarburized
or uncarburized malleable iron or steel of a cupola furnace enclosed or
partially enclosed in a chamber, into which the air for combustion is
forced at a pressure much in excess of the external atmosphere.
Secondly. The employment for the fusion of scrap or other decar-
burized or uncarburized malleable iron or steel of reverberatory furnaces
enclosed in a chamber, into which the air for combustion is forced at
a pressure much in excess of the external atmosphere.
Thirdly. The modes herein described of constructing and lighting
the close iron chambers in which melting furnaces for the melting of
scrap or other decarburized or uncarburized malleable iron or steel are
worked at high pressure.
Fourthly. The constructing chambers containing high-pressure
furnaces for the melting of scrap or other decarburized or uncarburized
malleable iron or steel with double inlet doors, combined with inlet
and outlet pipes, as herein described.

page_text: Fifthly. The causing compressed air before entering a chamber con-
taining a high-pressure furnace for the melting of scrap or other decar-
burized or uncarburized malleable iron or steel to pass through suitable
cooling apparatus for the purpose herein described.
Sixthly. The general arrangement and combination of parts con-
stituting the melting and casting apparatus shewn in Figures 1, 2,
and 3 on Sheet B. of the annexed Drawings.
In witness whereof, I, the said Henry Bessemer, have hereunto
set my hand and scal, this Tenth day of November, in the year
of our Lord One thousand eight hundred and sixty-nine.
HENRY BESSEMER. (L.S.)