IMPROVEMENTS IN
Year: 1853

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, and of Glasgow, North
Britain, Gentleman, for the Invention of "IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said John Henry
Johnson at the Office of the Commissioners of Patents, with his
Petition, on the 10th December 1858.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, and of Glasgow, North Britain, Gentleman, do hereby
declaro the nature of the said Invention for "IMPROVEMENTS IN FURNACES
FOR THE MANUFACTURE OF STEEL," being a communication from abroad, to
be as follows:-
This Invention consists of certain peculiar constructions of furnaces
for the manufacture of cast steel, whereby great economy of fuel and
expenso of working is effected. The first arrangement consists in the
use of two melting chambers or furnaces with one chimney and ash

page_text: pit. These chambers are placed one on cach side of the ash pit, and
contain the crucibles for melting the metal. The gases from these
chambers pass into one common chimney, and on their way thereto
they may be made to heat a steam boiler. An opening is formed
beneath the grates on which the crucibles rest, for the attendant to
examine the state of the furnaces. These openings communicate with
an inclined passage which leads to an ash pit. A metal plate is
employed to catch the steel should it escape from the crucibles, and
prevent it from mixing with the cinders. There are several furnaces
to cach melting chamber, and on one side of the chimney are arranged
the furnaces for the baking of the crucibles. A second arrangement
consists in the adoption of double heating or melting chambers heated
by one furnace, and having also only one chimney. The crucibles are
arranged on each side of the furnace. Beneath the grate in the ash
pit is introduced a pipe for supplying air to the furnace, either hot or
cold. In these furnaces an inferior fuel may be employed, such as pit
coal, in place of coke. The roof of these chambers is made arched, with a
projection in the contre, so as to diverge the heat and flame, and causes
them to beat round the crucibles; the chambers may also be divided
into several compartments, if necessary, affording thereby facility for
examining them separately without interfering with the rest. The heat
in this arrangement may also be employed to heat a steam boiler, if
desired, or it may be made to heat the air which is admitted into the
furnaces. This arrangement affords facility for working at will with
either hot or cold air. A third arrangement consists of a furnace with
one large or two smaller crucibles, for melting or heating a largo amount
of metal at ono time. This crucible or crucibles are placed in a
chamber over the furnace with a perforated top, so that the heat and
flame will enter the chamber, and play round the crucibles, from thence
they pass through passages leading either to separate or distinct
chimneys. Several openings are formed in the top of the crucibles for
the admission of the metal, and these holes are afterwards stopped up
with clay. Similar corresponding holes are formed in the top of the
chamber containing the crucible or crucibles. An opening is formed
in the end of the crucible, for the facility of running off the metal. A

page_text: large door is formed in one side of the crucible chamber to admit the
crucible, and the furnace is supplied with air by a number of pipes
opening into the ash pit. By a very slight modification this last-
described furnace may be made to heat a large number of small
crucibles without altering the principle of its action.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 10th June 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of Glasgow, North Britain, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of December, in the year
of our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, admi-
nistrators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, or assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 In-
vention for "IMPROVEMENTS IN FURNACES FOR THE MANUFACTURE OF STEEL,"
a communication from abroad, upon the condition (amongst others)
that I, the said John Henry Johnson, by an instrument in writing
under my hand and seal, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to bo
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the dato
of the said Letters Patent.
T

page_text: hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer
tained in and by the following statement, reference being had to the
accompanying Drawings, and to the letters and figures marked thereon,
that is to say:-
:
The said Invention relates to the arrangement and construction of
furnaces for the manufacture of cast steel, whereby great economy of
fuel and working expenses is effected. One arrangement consists in
the use of two melting chambers or furnaces with one chimney and ash
pit. These chambers are placed one on each side of the ash pit, and
contain the crucibles for melting the metal. The gases from these
chambers pass into one common chimney, and on their way thereto they
may be made to heat a steam boiler. An opening is formed beneath
the grates on which the crucible rests for the attendant to examine tho
state of the furnaces. These openings communicate with an inclined
passage which leads to an ash pit. A metal plate is employed to catch
the steel, should it escape from the crucibles, and to prevent it from
mixing with the cinders. There are several furnaces or fires to cach
melting chamber, and on one side of the chimney are arranged the
furnaces for the baking of the crucibles. A second arrangement con-
sists in the adoption of double heating or melting chambers heated
by one furnace, and having also only one chimney; the crucibles are
arranged on each side of the furnace. Beneath the grate in the ash
pit is introduced a pipe for supplying air to the furnace, either hot or
cold. In these furnaces an inferior fuel may be employed, such as
coal, in place of coke. The roof of these chambers is arched with a
projection in the centre so as to spread the heat and flame to act well
upon the crucibles. The chambers may also be divided into several
compartments, if necessary, affording thereby facility for examining
them separately without interfering with the rest. The heat in this
arrangement may also be employed to heat a steam boiler, if desired,
or it may be made to heat the air which is admitted into the furnaces.
This arrangement affords facility for working at will with either hot or
cold air. A third arrangement consists of a furnace with one large or
two smaller crucibles for melting or heating a laige amount of metal

page_text: at one time. The crucible or crucibles are placed in a chamber over
the furnace with a perforated top, so that the heat and flame will
enter the chamber and play round the crucibles, whence the heat passes
through passages leading either to separate or distinct chimneys.
Several openings are formed in the top of the crucibles for the admis-
sion of the metal, and these holes are afterwards stopped up with clay;
similar corresponding holes are formed in the top of the chamber con-
taining the crucible or crucibles. Au opening is formed in the end of
the crucible for the facility of running off the metal. A large door is
formed in one side of the crucible chamber to admit the crucible, and
the furnace is supplied with air by a number of pipes opening into the
ash pit. By a very slight modification this last-described furnace may
be made to heat a large number of small crucibles without altering the
principles of its action.
The first Sheet of Drawings represents the system of double furnaces
with one cominon ash pit, and shews the application of a steam boiler
heated by the waste heat. The furnaces may be worked either with
compressed air or not, as may be found desirable. Fig. 1 on Sheet 1 of
the Drawings represents a general plan or horizontal section of the
furnaces, taken at different elevations; Fig. 2 is a transverse section,
taken along the line 1, 2; Fig. 3 is a second vertical longitudinal
section, taken according to the line 3, 4; and Fig. 4 is a longitudinal
section, taken along the line 5, 6, and shewing the boilers or steam
generators in elevation.
As here arranged, two sets or series of fusing chambers, A, A', are
employed, each chamber containing two, three, four, or more crucibles.
The gases produced in these furnaces by combustion pass off by the
openings a, a', leading to the flues B, B', of the draught chimney C.
These flues are divided or separated by a third series of flues D, of smaller
dimensions, which by receiving constant currents of fresh cold air, have
the advantages of preserving the body of the chimney in good working
order, and permitting its sides to be made thinner than when they are
arranged against a wall, as in the old system.
Beneath each of the grates E, upon which the crucibles are placed
are formed lateral openings b, b', which communicate with the chimney.

page_text: These are the openings by which the attendant, who stands at e, e', can
see by the greater or less light which the flame and gasses produce in
the passages a, a', if the furnaces require fresh fuel. Beneath these
openings are formed the inclined passages c, c', formed in the masonry
or brickwork F. These passages communicate with the underground
passage G, which is, properly speaking, the ash pit. The object of the
inclined passages c, c', is to afford facility for removing the cinders from
the grates, and to effect a more complete fusion of the metal. A cast
iron plate D, of the width of each fire-place, rests upon the masonry F,
in order that when the metal runs over from any of the crucibles, which
frequently occurs, the steel falls on to this plate, and is not mixed with
the cinders, an accident which, when it occurs, materially deteriorates
the metal. By this arrangement these "runnings" are easily worked
again, without much trouble in cleaning them, which is an undoubted
advantage in cast steel manufactures. The ash pit G also embodies
a considerable improvement, as, being completely open at each end, it
affords a large supply of atinospheric air to the furnaces through the
small openings c, c'. Ten of these furnaces are represented in the
Drawings on each of the ash pit, but it is obvious that a greater or
less number may be employed. On the left of the base of the chimney
are situated a series of ovens, for the purpose of baking the crucibles
before using them; the arrangement of these ovens is very simple and
economical, inasmuch as there is only one common chimney from which
the
gases are discharged into the air passage. An opening is formed on
the opposite side, for the purpose of running off large castings of from
one to two tons weight, a suitable mould being placed beneath, resting
upon a solid foundation. The employment of two series of melting
chambers, as herein-before described, is of great advantage. This
arrangement permits of a steam generator i, being placed above the flues
or hot air passages, as shewn in Figs. 3 and 4, whereby the otherwise
waste heat of the twenty furnaces is advantageously employed. This
arrangement affords facility also for the application of compressed air
or blowing engines for accelerating the melting of the metal, the pas-
sages c, c, and openings e, e', being simply closed by dampers F', and
the nir forced into the furnaces beneath their grate bars by the blast

page_text: pipe j, in communication with a suitable blowing engine. By this
application, ordinary coal, or anthracite, or other cheap combustibles,
may be burned with facility, in place of coke. The advantages obtained
by these furnaces are, cheapness of construction, speed, and facility of
working, economy of fuel and manual labor, less waste, and a better
description of metal. The other two Figures on the same Sheet of
Drawings represent another improved arrangement of double furnaces
or melting chambers, which may also be worked with one common ash
pit, and one grate, and with or without the use of an artificial blast.
Fig. 5 is a vertical section taken trough the centre of the furnace;
and Fig. 6 represents a longitudinal section of the same, taken along
the line 1, 2. These Figures represent but one system, composed of
ten crucibles, arranged in series of five on each side of the fire-place B,
making in all twenty crucibles for the whole length of the grato C; but
this number may be increased by prolonging the grate to the requisite.
extent. When it is desired to work the furnace by a blast of air intro-
duced beneath the grate bars, or in the ash pit D, a blast pipe E,
communicating with any suitable blowing engine, is fitted into tho
masonry, as shewn in Fig. 5. By this means an inferior or cheaper
description of fuel may be employed, as herein-before described; by
arranging the crucibles, as shewn in Fig. 5, a little above and on each
side of the grate bars, all the heat rises to the top of the furnace,
and is made to divergo right and left, as shewn by the arrows; by
impinging against the projection F, and passing over the bridges G,
into the interstices or spaces between the several crucibles, it eventually
escapes by the single or double flues II, into one common draft
chimney. The double furnace, or, more properly speaking, the melting
chamber, on each side of the grate and ash pit, is supposed to bo
divided into compartments of a certain capacity suitable for receiving
several crucibles, as shewn in Fig. 6. Each compartment is separated
or divided from the rest by a partition i, and each may be examined
separately through the corresponding openings above, which are closed
by the stoppers J, composed of brick or fire clay. Should any portion
of the furnace require repair, one side only may be worked, whilst
the other is being set in order. The waste heat may also be employed

page_text: for generating steam, as herein-before described, and the blast pipe
may be placed in the brickwork of the furnace itself, whereby the air
will become considerably heated before entering the furnace. Figs. 7
to 9, on Sheet 2 of the Drawings, represent furnaces for containing
one or two large crucibles suitable for melting a large amount of metal
at one time; Fig. 7 is a vertical section taken through the centre of
the furnace with one crucible; and Fig. 8 is a transverse section of the
same, taken along the line 1, 2. This arrangement is exceedingly
simple in construction, as it consists merely of a furnace or fire-place
A, constructed according to the size of the crucible, and to the quantity
of metal to be melted. The grate B may also be fed or supplied with
inferior fuel in place of coke, as in the arrangements herein-before
described. The fuel is fed in by the opening C, which may be closed
either by a cast or wrought iron door, lined internally with fire brick
or other similar material. The top of the furnace is arched at D, and
perforated by a number of oblique passages or openings I, by which
the flame and smoke may enter the upper chamber E, enclosing the
large crucible F, or two crucibles F, F, as in Fig. 9, the size of the
furnace being of course increased in proportion. The result is that
the whole of the external surface of the crucibles is equally heated, and
the flame and heat, after circulating round the crucibles, passes off*
by the flues G, which may communicate with one common chimney or
two distinct chimnies as found most convenient. A number of open-
.ings a, are formed in the top of the crucible, by which the metal is
introduced therein; these openings are closed by plugs of clay, which
be removed when it is required to examine the state of the metal.
Corresponding holes G, are also made in the top J, of the chamber E,
which are also closed by plugs of clay d, such plugs being withdrawn
each time the state of the metal is required to be examined. The
.bottom of the crucible, which may be slightly inclined, is perforated
at e, Fig. 7, through which the metal is run off when ready for that
operation. In order to introduce the crucible into the interior of the
-furnace, a large aperture is formed in one end of the chamber, closed
by a cast or wrought iron door H, lined inside with fire clay, as before
described. Lateral passages K, are formed inside the masonry, running
may

page_text: the entire length of the furnace, to allow a free circulation of fresh
air through the brickwork, to keep it cool. To increase the action of
the furnace, a number of blast pipes or tuyêres L, open underneath
the grate bars in the ash pit, such tuyêres being in communication
with any suitable blowing apparatus. The admission of air is regu-
lated by means of suitable cocks or valves f. Should a hot blast be
required, the pipes may pass through the furnace, and the air be con-
sequently heated before issuing from the mouths of the tuyêres. This
latter arrangement is shown in Figs. 10 and 11, which represent a
form of furnace similar to that last described, but adapted for contain-
ing a number of smaller crucibles. Fig. 10, represents a vertical
section taken through the centre of the furnace, and Fig. 11, is a
transverse section of the same taken along the line 3, 4. This furnace
is very similar in construction to that represented at Figs. 7 and 8,
the principal difficulties being in the number and form of the crucibles.
The floor on which the crucibles rest consists of a kind of grate, being
perforated over its entire surface by a series of holes or passages for
the flame. In this arrangement, as in the former ones, all the heat is
economised and turned to account, and the examination of the metal
during the process of melting is easily offected. A number of these
furnaces may be arranged side by side or in any other form, and com-
municating with one common chimney; they may also be supplied
with air, either hot or cold, by one common blast pipe and blowing
engine. The brickwork of each furnace is strengthened by hoops or
bands of iron, as in puddle and other similar furnaces; or, in place of
being worked conjointly, each furnace may be worked distinctly from
the rest, to admit of repairs being effected in any one of them without
interfering with the remainder.
Having now described and particularly ascertained the nature of
the said Invention, and the manner in which the same is or may
be used or carried into effect, I would observe, in conclusion, that
precise details or arrange-
I do not confine or restrict myself to the
ments which I have had occasion to describe or refer to, as many
variations may be made therefrom without deviating from the principles
or main features of the said Invention; but what I consider to be novel

page_text: and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,―
First, the general arrangement and construction of furnaces employed
in the manufacture of cast steel, wherein an inferior quality of fuel
may be burnt, in place of coke, as herein-before described.
Second, the system or mode of constructing furnaces employed in
the manufacture of cast steel, wherein two series of melting chambers
are used situate on each side of one common ash pit, and communi-
cating with one common chimney, as herein-before described.
Third, the system or mode of heating steam boilers by means
of the otherwise waste heat from such furnaces, as herein-before
described.
Fourth, the system or mode of constructing furnaces employed in the
manufacture of cast steel, wherein two series of melting chambers are
heated by one furnace or grate, worked with a hot or cold blast, as
herein-before described.
Fifth, the application of the above description of furnaces to the
melting of large masses of metal, as herein-before described.
In witness whereof, I, the said John Henry Johnson, have
hereunto set my hand and seal, this Tenth day of June, in
the year of our Lord 1854.