IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND INGUT IRON, AND IN THE APPARATUS USED MILE
Year: 1879

page_text: LETTERS PATENT to Sidney Gilchrist Thomas, of 3, Queen's Road Villas,
Wandsworth Road, London, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF STEEL AND INGUT IRON, AND IN THE APPARATUS USED
MILE"
Sealed the 25th June 1880, and dated the 29th December 1879.
PROVISIONAL SPECIFICATION left by the said Sidney Gilchrist Thomas at
the Office of the Commissioners of Patents on the 29th December 1879.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Wandsworth Road, London.
"IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND INGOT IRON, AND IN THE
APPARATUS USED THEREIN."
My Invention relates to various improvements in my processes for the manufacture
of steel and basic furnace linings, as described in my Patents No 908, in the year
1878; No. 289, in the year 1878; and No. 1313, in the year 1879; No. 1711, in
the year 1879.
My present improvements are as follows:-I have previously directed the use of
hot lime in the converter. I now find that the heating of this lime is effected with
great convenience and economy by mixing the lime, which I prefer to be in very
small pieces, with small coal and some live coals and throwing it into the converter,
and then turning on the blast so as to burn the small coal in intimate contact with
the lime.
I also have found a great economy results from utilising the waste heat from the
kilns for burning.
My basic bricks by leading the flue, which serves three (3) or more kilns, into the
bottom of a lime kiln of suitable construction, closed by a bell and hopper, or
similar arrangement, and connected with a stack. I always prefer the kiln to bo
near the converter so as to use the lime fresh and hot from the kiln.
I also make the nose or throat section of the basic lined converter easily removable
and renewable.
I sometimes make it fitting quite loosely, the converter having a large deep belly
section, so that the metal can be retained in the belly without reaching the loose
joint by which the throat section is attached to the body of the converter. In this

page_text: case I pour the metal from a point below the throat section, the upper section being
merely used to prevent metal being thrown out during the boiling period and to
retain the heat in the vessel.
I have sometimes found it useful to line the nose section with rammed material,
or silica, or best fire-bricks.
By these means I prevent the slag accumulating at the nose, causing delay.
I also introduce in the upper part of the vessel a blast of air leading either from
the ordinary blast pipe or supplied by a fan with a low pressure blast.
The blast may be either directed downwards, or, as I prefer it, so as to cause the
flame to just impinge against the upper part of the nose; by this means a very
intense heat is maintained in the throat of the vessel and any accumulation of slag
effectually prevented.
In order to accelerate the rate of working of the Bessemer plant I have found it
convenient to arrange four vessels to a pit in two pairs. The vessels are arranged
at each end of two revolving beams or turn-tables, so that when one vessel needs
repairs it is swung round and the vessel at the other end of the beam takes its place
facing the casting pit. In this way there is never any stoppage of work.
My next improvement refers to the manufacture of basic converter bottoms
These I manufacture cither wholly of rainmed material, or partly of bricks and
partly rammed. In making the rammed bottom I make the bottom in two sections,
one being an annular ring, the second a conical plug fitting into the annular
ring.
By this means the bottoms can be readily dried and made much harder than
when in one piece.
The brick bottom I build of basic bricks in the usual cast-iron ring, in the
bottom plate are fixed iron rods corresponding in number and position to the desired
twyer holes; round these rods in building up the hottom I leave a free space of
three (3) or four (4) inches diameter, which I afterwards fill up by ramming lime
and boiled tar hard round the rods, which after coking are knocked out.
I also sometimes form the blast-holes by thin wrought iron tubes, round which I
ram the basic material. Or I make twyers by casting them in very mild steel,
using only a small number of boles.
I also sometimes use part of the very calcareous basic slag produced in the
converter as the material for forming converter bottoms in admixture with lime.
I find it useful to run off the slag from the converter into a conical-shaped slag
bogey, which I prefer to set on the opposite end of the ladle crane to the casting
ladle; the bogey is capable of being readily run on and off the crane, and is
arranged so as to have a radial motion along the crane.
I find that white iron containing less than one and a quarter per cent. of silicon,
and loss than about three tenths per cent. of sulphur, with preferably at least one (1)
per cent of manganese, makes excellent steel when blown in lime lined converters
with from fifteen (15) to twenty (20) per cent. of lime addition.
Instead of adding spiogel, a small quantity of ordinary phosphoretic pig iron,
free from sulphur, may be added to the dephosphorised metal, which is then again
blown for a short time and then cast as usual.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sidney Gilchrist Thomas in the Great Seal Patent Office on the
28th June 1880.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Wandsworth Road, London.
IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND INGOT IRON, AND IN THE
APPARATUS USED THEREIN."
My Invention relates to improvements in my processes for the manufacture of
steel and basic linings, as described in my Patents No. 908, in the year 1878;
No. 289, in the year 1878, and No. 1313, in the year 1879; and No. 1711, in the
year 1879, and in the apparatus used in carrying out my said processes. My improve-
ments are as follows:-I have previously directed the use of hot lime in the con-
verter, I now find that the heating of this lime is effected with great convenience
and economy by mixing the lime, which I prefer to be in small pieces just large
enough not to be blown out by the blast, with small coal and some live coals, and
throwing it into the converter which is about to be used. I then turn on the blast
so as to burn the small coal in intimate contact with the lime in the converter, thus
simultaneously heating the lime and the converter. I have found also that a
considerable economy results from utilizing the waste heat from the kilns for
burning my basic bricks in which a very intense temperature is used by leading
the main flue, which serves three (3) or more brick kilns, into the bottom of a
circular lime kiln of suitable construction, which may be used for burning the lime
additions which I use in the converter. The gas may conveniently be brought into
the kiln by means of a brickwork flue carried up into the kiln from below to a
heighth of about three feet from the bottom. The flue is closed at the top, the
gases entering the kiln through a series of slits in the sides of the said fluc. The
kiln is closed by a double bell and hopper or similar arrangement for charging,
and connected at the top with a very high stack so as to give a sufficient draught.
When practicable I of course prefer the kiln to be near the converter, so as to use
the lime fresh and hot from the kiln. I also when treating pig iron, which does
not blow very hot, so that slag gathers rapidly at the orifice, find it useful to make
the nose or throat section of the basic lined converter, the actual throat of which I
contract to about 20 inches clear inside the lining, easily removeable and renewable.
I sometimes make it fitting quite loosely, being secured by swinging bolts and
cotters or supported by chains or rods from above, so as to be quite independent of
the body of the converter. I prefer a converter having a large deep belly section,
so that the metal can be retained in the belly without reaching the loose joint by
which the throat section is attached to the body of the converter except at the
moment of pouring. In this case I sometimes pour the metal from an opening
below the throat section, the upper section being merely used to prevent metal
being thrown out during the boiling period and to retain the heat in the vessel. I
have also found it useful to line the nose section for from 18 to 40 inches down
with silica or best fire-bricks, such as refractory pot clay bricks or bauxite bricks,
the rest of the vessel being lined with the lime linings the calcareous slag does not
adhere to these materials so readily as it does to lime. By these means I prevent
the slag accumulating at the nose and so causing delay. I also introduce into the
upper part of the breast of the vessel a blast of air, leading either from the ordinary
blast pipe, or supplied by a fan with a low-pressure blast The blast may be either
directed downwards, or, as I prefer it, so as to cause the flame to just impinge
against the upper part of the nose; by this means a very intense heat is maintained
in the throat of the vessel and any accumulation of slag effectually prevented. In
order to accelerate the rate of working of the Bessemer plant, I have also sometimes
found it convenient to arrange four vessels to a pit in two pairs. The vessels are
arranged at each end of two revolving beams or turn tables, so that when one vessel

page_text: needs repairs it is swung round and the vessel at the other end of the beam takes
its place facing the casting pit. In this way thero is never any stoppage of work.
I do not claim as novel or part of my Invention this arrangement of vessels on
revolving beams, nor the introduction of blast into the upper part of the converter,
but merely mention them as convenient and useful arrangements which may be
used in carrying out my Inventions. My next improvement relates to the manu-
facture of basic converter bottoms. These I manufacture either wholly of rammed
material, or partly of bricks and partly ramined. In making the rammed bottom I
make the bottom in two sections, one being an annular ring, the second a conical
plug fitting accurately into the annular ring If the whole bottom or plug have
a total diameter of 54 inches the inner plug may be conveniently of 15 or 20 inches
diameter. The outer or annular bottom is of course rammed and driod in an
annular iron casing, and the inner plug is rammed in a separate casing, they can
thus be dried or fired separately so as to enable the heat to penetrate through and
the drying to be more complete. This also enables the bottom to be more readily
compressed before drying by a hydraulic or other press so as to get a very dense
material. By this means the bottoms can be readily dried and made much harder
than when in one piece. When making a brick bottom I build it of basic bricks
in the usual cast iron ring, in the bottom plate are fixed iron rods corresponding
in number and position to the desired tuyere holes; round these rods in building
up the bottom I leave a clear space of thice (3) or four (4) inches diameter, which
I afterwards fill up by ramming hard with shrunk lime and boiled tar round the
rods, which after or before coking the bottom are knocked out. It is convenient
in most cases to make the bottoms at least 25 inches thick. I also, in situations
where dolomite is dear, use part of the very calcareous basic slag (containing under
15 per cent. of silica) produced in the converter or open hearth furnace when
working my basic process as the material for forming converter bottoms in
admixture with lime and boiled or Siemens' tar, this slag can also be used mixed
with lime or limestone for repairing Siemens' hearths. The slag and lime should
be used in such proportion that in the mixture there should be under 15% of silica,
alumina, and oxide of iron. I find it useful to run off the slag from the converter
into a conical shaped slag bogey, so as to drain off any iron left in the slag which
accumulates in the bottom of the bogey. I do not however claim this as part of
ny Invention, but merely mention it as a convenient arrangement.
Having thus described the nature of my said Invention and in what manner tho
same may be employed, what I claim and desire to secure by Letters Patent is, the
improvements in the manufacture of steel and ingot iron and in the apparatus used
therefor, substantially as herein described and set forth.
In witness whereof, I, the said Sidney Gilchrist Thomas, have hereunto set
my hand and seal, this Twenty eighth day of June, in the year of our Lord
1000