IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE CAST IRON AND CAST STEEL, AND IN FURNACES THEREFOR
Year: 1872

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE
CAST IRON AND CAST STEEL, AND IN FURNACES THEREFOR."-A communica-
tion from abroad by Jonathan M. Roberts, of Burlington, New
Jersey, United States of America.
Sealed the 18th February 1873, and dated the 5th December 1872.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition,
on the 5th December 1872.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
MALLEABLE CAST IRON AND CAST STEEL, AND IN FURNACES THEREFOR," a com-
munication, to be as follows:-
This Invention relates to the manufacture of malleable cast iron and
I cast steel, and to furnaces employed therefor. The object of the said

page_text: Invention is to provide the necessary mechanical devices for effecting
economically the purification of crude cast iron, and its direct conversion
into malleable cast iron or steel, as may be desired.
In practising the said Invention, I employ a crucible constructed of
proper refractory material placed within a close chamber intermediate
between the fire-box and the smoke stack, so that the crucible in use is
enveloped on all the outer sides of its periphery with intense heat nearly
in a state of rest, while the contents of the crucible are not subjected to
the direct contact of the flames. This crucible is also provided with a
cover fitting tightly and with convenient means for enabling the same
to be raised, and has also suitable tap holes for the removal of scoriae
and fluid metal placed at a point nearest the smoke stack. There is also
arranged between the fire-box and the crucible at the point where the
heat is greatest a suitable screen of such construction that the position
of the same may be conveniently changed. The said crucible is not
intended to be removed from the heating chamber, but it is so arranged
that it may be filled and its contents agitated or withdrawn without
changing the position of the crucible. The time necessary to accomplish
the conversion is so great that no furnace heretofore used will admit of
the iron remaining in the furnace sufficiently long to complete the
purification and conversion of the iron, and to allow it to become entirely
homogeneous by the metal standing without agitation before being.
tapped from the furnace.
In my improved furnace the process may be protracted at the pleasure
of the operator without any material loss or deterioration of the product.
On a platform or bearth I construct a working chamber or crucible of
sufficient capacity to work at one heat any amount, from five hundred
pounds to ten thousand pounds of crude metal; I prefer to build this
chamber circular. This working chamber I construct of suitably formed
staves or sectional slabs which must be composed of the most durable
fire-proof materials, and must be made long enough to extend at least
four inches below the floor of the surrounding heating passage or
chamber and up through the roof. The staves must be from five to
eight inches thick, and when placed together and the intervening joints
between them are perfectly luted with good fire-proof cement, they will
form a durable and tight wall for the working chamber. The said
staves should also be formed with a rectangular recess on the outer side

page_text: at the top to receive and support the roof tile, they should also be
beveled or chamfered on the inner side at the top to give ready access
to the working tools when the cover is slightly raised. The wall is
firmly supported and bound at the top and bottom by the roof tiles, and
the floor of the surrounding heating chamber. Near the bottom of the
crucible and opposite the tap hole door in the side of the furnace next
to the smoke stack I provide two or more tapping holes one above the
other for drawing off the fused scoriae and the metal.
A moveable cover is provided of a shape corresponding with the mouth
of the chamber. This cover must be made of good fire-proof materials,
it must be bound firmly with an iron clamp, and provided with loops,
rings, or hooks for attaching the apparatus used in handling it. When
this lid is lowered on the chamber it should exclude the air, and when
slightly raised should form an opening around the edge of it for the
convenient introduction of the working tools. From the top of the
outer wall of the furnace heavy fire-tiles are laid across the top of the
fire-chamber and rest in the rectangular recess in the top of the crucible
wall. At the front of the heating chamber an opening is left
corresponding with the width of the fire-chamber and high enough
to permit free access of the heat to the wall of the crucible or working
chamber and around it. At the back of the heating chamber and
directly opposite the front opening another opening is left in the furnace
wall extending the whole height of the heating chamber, which opening
is narrowed sufficiently to partially obstruct the heat current in its passage
to the stack. A fire-brick neck or flue corresponding in dimensions with
the opening leads to the stack and connects the heating chamber with
the flue of the latter. A suitable screen of fire-clay or other suitable
material is placed directly between the fire-box and the crucible; it is of
such construction that it will stand firmly, and is capable of being
conveniently moved in position by the appliances in ordinary use. The
furnace must be provided with blowing apparatus and the usual
dampers.
"
The method of using this improved furnace is as follows:-I construct
the bottom or working bed in the chamber of any durable fire-proof
compound such as is used for lining the Bessemer convertors or for
similar purposes.
This working bed must be formed to receive within
it the whole mass of fused materials that will constitute the charge

page_text: intended to be operated upon at one time, and should be made to extend
high enough to prevent the contact of the molten materials with the
walls of the working chamber. It must be so formed that the melted
metal and slag can all be drawn off through the tap holes. The furnace
is now ready for firing, and this should be done very gradually until
every part of the furnace is completely dried and freed from all moisture.
The lid or cover should be kept down or closed until the crucible
becomes heated sufficiently to melt cast iron readily. When heated to
this point the lid must be raised sufficiently to introduce the crude cast.
iron. This may be done by charging broken pig iron directly into the
furnace or by drawing it melted from a cupola furnace conveniently
placed for that purpose, or directly from the blast furnace. When the
charge of iron is in the furnace or working chamber and completely
fused, the work of purification may be commenced. If the crude iron is
poor in carbon and fuses but imperfectly it may be made to do so freely
by adding spiegeleisen, Franklinite iron, or any other more highly
carbonized iron in sufficient quantities.
When the fusion is completed the purification of the iron may be
effected by means of any of the oxidizing substances used for that
purpose, which are to be introduced and intermingled with the molten
metal. Oxide of iron, oxide of manganese, oxide of titanium wolfram,
furnace and hammer slag, and many other substances which supply
oxygen largely may be used to the best advantage in this furnace for
oxidizing the impurities of the crude iron and removing them from it.
In addition to the above oxidizing agents atmospheric air may be
blown into and through the molten metal by means of a hollow rabble
of suitable shape. While introducing the materials and working the
change the lid must be slightly raised, but at all other times should be
kept lowered or closed. If the impurities of the iron are very con-
siderable, and the supply of carbon in the metal insufficient to produce
the required heat in the working chamber, pulverized charcoal or equiva-
lent material as pure as can be obtained, may be introduced from time
to time. If too much carbon be removed from the iron when the work.
of purification is complete, it can readily be introduced by using the
necessary quantity of spiegeleisen or manganiferous iron.
Having attained the condition of purification and carbonization desired
the lid of the crucible must be tightly closed, and the heat of the furnace

page_text: kept up to the melting point of steel or malleable cast iron for any
length of time required to allow of the complete intermingling of every
part of the metal and until it has acquired a uniform and homogeneous
condition throughout. When this condition is attained, the metal is
drawn out through the tapping hole and cast into ingots for rolling or
forging.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 27th May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting."
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of December, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Robert Lake, Her special
licence that I, the said William Robert Lake, my executors, adminis-
trators, and assigns, or such others as I, the said William Robert Lake,
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 MANUFACTURE OF MALLEABLE CAST IRON AND CAST STEEL,
AND IN FURNACES THEREFOB," a communication to me from abroad by
Jonathan M. Roberts, of Burlington, New Jersey, United States of
America, upon the condition (amongst others) that I, the said William
Robert Lake, 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.
"

page_text: NOW KNOW YE, that I, the said William Robert Lake, 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, reference being had to the accompanying
Drawings, forming a part of this Specification :-
This Invention relates to the construction of furnaces used for making
malleable cast iron and cast steel. The object of the said Invention is
to provide the necessary mechanical devices for effecting economically
the purification of crude cast iron, and its direct conversion into malle-
able cast iron or steel, as may be desired.
In practising the said Invention I use a crucible of peculiar con-
struction made of proper refractory material placed within a close
chamber intermediate between the fire-box and the smoke stack, so
that the crucible in use is enveloped on the outer sides of its periphery
with an intense heat nearly in a state of rest, while the contents of the
crucible are not subjected to the direct contact of the flames. This
crucible is also provided with a cover fitting tightly, and there are
convenient means for raising or lowering the same. The said crucible
has also suitable tap holes for the removal of scoriae and fluid metal
placed at a point nearest the smoke stack opposite tap hole doors in
the side of the furnace similarly arranged; by this arrangement the
incoming currents of air, when such doors are opened, are directed
instantly into the smoke stack without sensibly diminishing the tempe-
rature of the heat immediately around the crucible. There is also placed
between the fire-box and the crucible and the point where the heat
from the fire-box most strongly strikes the nearest side of the crucible,
a suitable screen of proper refractory material, and of such construction
that the position of the same may be conveniently changed by the
furnace operator with ordinary appliances.
The said crucible is not intended to be removed in use, but is so
constructed and arranged that it may be filled and its contents agitated
or withdrawn without changing its position. The time necessary to
accomplish this is so great that no furnace hitherto used will admit of
the iron remaining in the furnace sufficiently long to complete the
purification and conversion of the iron, and to allow it to become
entirely homogeneous by the metal standing without agitation before
being tapped from the crucible.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical sectional clevation through the middle of the
furnace from the front to the back of the same.
Figure 2 is a view of the top of the furnace with a part of the roof
and cover removed.
Figure 3 is a perspective view of the said furnace as seen when
completed, showing tap hole, platform for workmen, appliance for
removing cover, and the relative position of the fire-chamber body of the
furnace, furnace neck, and stack.
Like letters indicate the same parts throughout the Drawings.
On a platform or hearth R at such an elevation relatively to the
grate B of the fire-chamber A as will permit the most effective action
of the heat I construct a working chamber or crucible E of sufficient
capacity to work at one heat from five-hundred pounds to ten-thousand
pounds of crude metal; I prefer to build this chamber E circular, as it
is then better adapted to the binding of the furnace and the utilization
of the heat. This working chamber E I construct of staves or sec-
tional slabs F of the form shown in the Drawing; they must be
composed of the most durable fire-proof materials and must be long
enough to extend at least four-inches below the floor of the surrounding
heating passage or chamber D and up through the roof L. The staves F
must be from five to eight-inches thick, and when placed together the
intervening joints between them are perfectly luted with good fire-proof
cement, and they will form a durable and tight wall for the working
chamber E. The said staves F should also be formed with a rectangular
recess on the outer side at the top to receive and support the roof tiles L,
they should also be beveled or chamfered on the inner side at the top,
as shown in Figure 1, to give ready access to the working tools when the
cover is slightly raised. The wall F is firmly supported and bound at
the top and bottom by the roof tiles L and the floor of the surrounding
heating chamber D. Near the bottom of the crucible and opposite the
tap hole door O in the side of the furnace (which tap hole door is made

page_text: as close as possible to the smoke stack) and corresponds with the tapping
holes herein-after described, I provide two or more tapping holes, onc
above the other, for drawing off the fused scoria as it is formed, and
also the metal when the operation is completed. The height of the
working chamber E may be varied but must be sufficient to present an
adequate exterior surface to the action of the fire to produce the required
temperature within the working chamber; it may advantageously be
from fifteen to thirty-six inches high. A movable cover I is provided
of a shape corresponding with the top or mouth of the chamber E; this
cover may be made in one piece or a number of pieces but must be
made of good fire-proof materials, and it must be bound firmly with an
iron clamp and provided with loops, rings, or hooks for attaching the
apparatus used in handling it. When this lid I is lowered on the
chamber E it should exclude the air, and when slightly raised should
form an opening around the edge of it for the convenient introduction
of the working tools to all parts of the bottom of tlie working
chamber E. For this purpose I bevel or chamfer the under part of the
edge of the lid to correspond with the chamfered mouth of the working
chamber.
Around the said working chamber E and at from ten to fifteen
inches from the exterior of it I construct the wall J of the furnace of
good fire-bricks. The exterior of this wall must correspond with the
exterior of the platform or hearth R to facilitate the binding of the
furnace, which may be readily done by placing upright plates around the
body of the furnace and supporting them with strong iron hoops placed
above and below the fire-chamber A. From the top of the outer wall
J. of the furnace heavy fire-tiles are laid across the top of the fire-
chamber D and rest in the rectangular recess in the top of the crucible
wall F. These tiles must be formed especially for the purpose, and
should be thick enough to resist the heat without sinking down, and to
prevent as much as possible the radiation of heat to the annoyance of
the workmen. At the front of the heating chamber D an opening T is
left corresponding with the width of the firo-chamber, and high
enough to permit free acess of the heat to the wall of the crucible or
working chamber and around it. At the back of the heating chamber D
and directly opposite the front opening T another opening U is left in the
furnace wall extending the whole height of the heating chamber D, but

page_text: which is narrowed sufficiently to partially obstruct the heat current in
its passage to the stack. A fire-brick neck or flue G corresponding in
dimensions with the opening U leads to the stack N and connects the
heating chamber with the flue of the latter.
A suitable screen S of fire-clay or other proper refractory material is
placed directly between the fire-box and the crucible. It is of such con-
struction that it will stand firmly on its base and be capable of being
conveniently moved by the appliances in ordinary use. Both the fire-
chamber A and the throat or neck G must be securely fastened to the
body of the furnace and bound in the ordinary manner.
The said furnace must be provided with blowing apparatus and the
usual dampers to enable the workmen to regulate the heat. The heat
may be produced by the ordinary furnace fires or by gas furnaces, as
may be preferred. It is essential however to the successful working of
my apparatus that there should be a great body of intense heat without
rapid currents of the same towards the smoke-stack.
The method of using my improved furnace is as follows:- -I construct
the bottom or working bed in the chamber E of any desirable fire-proof
compound, such as is used for lining the "Bessemer" convertors or for
similar purposes. This working bed must be formed to receive within it
the whole mass of fused materials that will at any time constitute the
charge which is intended to be operated upon at one time, and should
extend high enough to keep the molten materials from touching the
walls of the working chamber. It must be formed so that the melted
metal and slag can all be drawn off through the tap holes. The furnace
is now ready for firing, and this should be done very gradually until
every part of the furnace is completely dried and freed from all moisture.
The lid or cover I should be kept down or closed until the crucible
becomes heated sufficiently to melt cast iron readily within it. When
heated to this point the lid must be raised sufficiently to introduce the
crude cast iron to be treated. This may be done by charging broken
pig iron directly into the furnace or by drawing melted iron from a
cupola furnace conveniently placed for that purpose, or directly from the
blast furnace when it can be conveniently done. When the charge of
iron is in the furnace or working chamber and completely fused the work
of purification may be commenced.

page_text: If the crude iron is poor in carbon and fuses but imperfectly it may
be made to do so freely by adding speigeleisen, Franklinite iron, or any
other more highly carbonized iron in sufficient quantities. When the
fusion is completed the purification of the iron may be effected by means
of any of the oxidizing substances used for that purpose, which are to be
introduced and intermingled with the molten metal. Oxide of iron,
oxide of manganese, oxide of titanium, wolfram, furnace and hammer
slag, and any other substances which supply oxygen largely may be
used to the best advantage in this furnace for oxidizing the impurities of
. the crude iron and removing them from it. In addition to the use of the
above oxidizing agents atmospheric air may be blown into and through
the molten metal by means of a hollow rabble of suitable shape.
While introducing the materials and working the charge the lid I
must be slightly raised, but at all other times should be kept lowered or
closed. If the impurities of the iron are very considerable and the
supply of carbon in the metal is insufficient to produce the required heat
in the working chamber E pulverized charcoal or equivalent material as
pure as can be obtained may be introduced from time to time. As all
action of the air upon the metal in the chamber E is under the control
of the workmen the iron may be kept in the furnace without waste or
injury as long as may be found necessary for its thorough purifica-
tion.
If too much carbon is removed from the iron when the work of purifi-
cation is complete it can readily be introduced by using the necessary
quantity of speigeleisen or manganiferous iron. Having attained the
condition of purification and carbonization desired the lid of the crucible
must be tightly closed and the heat of the furnace kept up to the melt-
ing point of steel or malleable cast iron for any length of time that may
be required to allow of the complete intermingling of every part of the
metal and until it has acquired a uniform and homogeneous condition
throughout. When this condition is attained the metal is drawn out
through the tapping hole and cast into ingots for rolling or forging.
This furnace is well adapted for the successful working of any of the
many purifying and carbonizing methods heretofore used, as it embodies
the advantages presented by the various furnaces employed, while it
avoids their defects.

page_text: Having thus fully described the said Invention as communicated to
me by my foreign correspondent and the manner of performing the
same, I wish it understood that I claim the improved furnace for the
manufacture of iron and steel, constructed and operated substantially as
described.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Twenty-sixth day of May,
in the year of our Lord One thousand eight hundred and seventy-
three
Witness,
JAMES EDWARDS,
8, Southampton Buildings,
London.
W. ROB. LAKE. (L.S.)