AN IMPROVED MODE OF MAKING REFINED, OR WHAT IS COMMONLY CALLED CAST STEEL
Year: 1824

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
THOMPSON, late of Pembroke Place, Pimlico, and of the London Steel Works,
Thames Bank, Chelsen, and now of Vincent Square, Westminster, Engineer,
send greeting.
WHEREAS His present most Excellent Majesty King George the
Fourth did, by His Royal Letters Patent under the Great Seal of the
United Kingdom of Great Britain and Ireland, bearing date at West-
minster, the Ninth day of December, in the fifth year of His reign, give
and grant unto me, the said John Thompson, my executors, admini-
strators, and assigns, His especial licence, full power, sole privilege and,
authority, that I, the said John Thompson, my executors, administrators, and
assigns, during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend my Invention of "AN IMPROVED MODE OF MAKING
REFINED, OR WHAT IS COMMONLY CALLED CAST STEEL," within England, Wales,
and Berwick-upon-Tweed, in such manner as to me, the said John Thompson,
my executors, administrators, and assigns, should in our discretion seem
meet; in which said Letters Patent is contained a proviso that if I, the said
John Thompson, should not particularly describe and ascertain the nature of
my said Invention, and in what manner the same is to be performed, by an
instrument in writing under my hand and seal, and cause the same to be
inrolled in His Majesty's High Court of Chancery within two calendar months
next and immediately after the date of the said Letters Patent, that then the
said Letters Patent, and all liberties and advantages whatsoever thereby

page_text: granted, should utterly cease, determine, and become void, as in and by the
suid recited Letters Patent, relation being thereunto had, may more fully and
at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Thompson, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are particularly
described and ascertained in the following Specification and Drawings
annexed :-
My improved method of making refined or cast steel consists, first, in
substituting the use of a common air reverberatory, or similar to what is called
in the manufacture of iron a puddling furnace, subject only to such variations
in its dimensions as the size of any trough or vessel to be placed in such
furnace may require, instead of the common upright air furnace universally
used for the making of steel. I recommend that the bottoms of the rever-
beratory furnaces to be used in pursuance of my improved method for making
of cast steel should be formed solid from the ground or foundation, and not to
be left open or hollow underneath, as generally is the case with puddling
furnaces. After adopting the usual means of lighting the fire in such furnaces
and getting up the furnace to a proper degree of heat by means of pit coal or
other suitable fuel; and, secondly, having previously placed one or more of my
stationary troughs or vessels (the construction of which I shall hereafter parti-
cularly describe) in a longitudinal direction across the furnace, directly facing
the centre of the furnace, taking care that each trough or vessel is placed upon
two or more fire bearers that are sufficiently strong to sustain each trough, and
adapted to the form of such trough, and to allow the fluid metal in each
trough to incline to its exit aperture, and by which bearers also the fire must be
allowed full scope or face for the flame or heat to have a free action underneath
and round the troughs or vessels placed in the furnace. The dimensions and
capacity of the trough or vessel that I recommend to be used will be about
two feet nine inches long, of a semi-cylindrical form of twelve inches diameter;
consequently it will be about six inches deep in the centre, with its ends
hemispherical, and will contain from one hundred and seventy to two hundred
and thirty pounds of iron or steel, but I do not confine myself to this shape or
dimensions. These troughs or vessels must be made of fire clay or fire stone,
or such other suitable materials as will sustain the necessary power of fire for
the fusion of wrought iron or steel. I find that the substance of these troughs
or vessels must not be less than an inch and a half thick. Every trough or
vessel must be formed to receive a curved lid or cover of the same length and
width of the trough, made of similar materials, and so constructed as to allow

page_text: it occasionally to be moved in order to shew the interior of the trough or
vessel while the iron or steel, which is therein placed, is under the operation of
fusion, as also for the purpose of re-charging the trough with metal, &c. In
the end of each trough or vessel which is nearest to the furnace door must be
made a hole of an inch and a half diameter, or thereabouts, a little below
the bottom of the trough, and into which hole I fix a platina socket, which,
when opened, will allow the fluid steel to pass into any mould or moulds; but
if no socket be used, then a hole of an inch diameter will be sufficient. I
surround this platina socket, properly connected to the trough or vessel, by a
pipe or tube of three inches diameter, or thereabouts, made of the same mate-
rials as my troughs or vessels, which is conducted through an aperture in the
brickwork of the furnace, and which pipe or tube in its area encloses the
platina socket, so that when the socket is untapped, and the metal in the
trough or vessel sufficiently fluid and ready for pouring, it runs along the pipe
or tube into the required mould or moulds for its reception. At every fresh
charge of iron or steel placed in the trough or vessel, it will be necessary to
stop or plug up the exit hole with sand or other suitable material, and when
the metal is ready to be tapped, then, by means of an iron bar or rod, which
I recommend to be covered or tipped, about three inches long, with platina, to
remove the stopping and to open the exit hole in the trough. These
platina substances will be found to introduce great. convenience and economy,
altho' a common iron rod and the trough or vessel without any platina
socket will answer sufficiently well to carry this part of my improved method
into effect; nevertheless I recommend the use of the former. It is essentially
necessary that the conducting pipe or tube to each trough or vessel should
have a moveable cover to prevent as much as possible any escape of heat
while the furnace is working. I strongly recommend when a furnace and
trough or vessel are in full operation (pursuing my improved mode of making
cast steel) that they should be kept constantly in action day and night by the
introduction of a suitable change of workmen as long as the trough or vessel
in which the iron or steel is melted shall be fit for such service. The great
advantages derived from my improved mode are, not only a very considerable
saving in fuel and crucibles, but the greatly increased quantity of steel that will
thereby be produced with the same expense for labor as would be incurred by
the old method of making cast steel, which is melted or fused in a crucible
that is enclosed in a small perpendicular air furnace heated by coke, and which
crucible is usually lifted out of the furnace by iron tongs with great labor and
hazard, not only to the workman but to the injury of the crucible and frequent
loss of steel before and while pouring into the mould or moulds, whilst my

page_text: improved method is relieved from all these difficulties and dangers, and has the
singular advantages of pouring or running the fluid steel into moulds without
lifting the trough or vessel out of the furnace, and the easy and rapid manner
in which this is done, and the trough or vessel again charged or filled with a
fresh supply of materials for fusion, and the heat again so readily got and kept
up, must be altogether so thoroughly obvious and useful to the steel manufacturer
that further explanation will be wholly unnecessary.
Figures 1 and 2 are views of a reverberatory or puddling furnace, with one
of my troughs or vessels placed upon the bearers, and inclining downwards a
little towards the furnace door for the purpose of allowing all the fluid metal
to run out of such trough or vessel when the orifice or tapping hole is opened
as before described. F, F, F, are the three bearers, upon which my trough
is placed in the furnace. Figures 3, 4, and 5 are views of one of my troughs
or vessels which I employ in my improved method of making refined or cast
steel. Figure 3 is a top view of my trough or vessel, with its hemispherical
ends, and its lid D. Figure 4 is a side view or longitudinal section, shewing
the tube or pipe A, A, which allows the fluid metal, when the trough or vessel
is tapped through the platina socket B, being opened or bored with the iron
rod tipped or covered also with platina. Figure 5 is a latitudinal section of my
trough or vessel, shewing the platina socket B and the end of conducting
pipe A, A, with the cover E slipped on the pipe, which must be kept always
on except when the trough is under the operation of stopping, tapping, or
pouring. My Invention and discovery for making refined or what is called
cast steel chiefly consists,―
First, of employing a reverberatory furnace instead of an upright air furnace,
by which pit coal can be used instead of coke; and,
Secondly, for a trough or vessel for the melting in such furnace the neces-
sary materials for the making of refined steel; and instead of crucibles I
employ my troughs or vessels, and by tapping and discharging their contents of
fluid metal while they are in the furnace into the desired moulds, and by never
removing them whilst they are capable of performing their duty, these are
the primary means by which I have performed and constituted my improved
mode of making refined or cast steel, and which I clain accordingly as before
described.
In witness whereof, I, the said John Thompson, have hereunto set my
hand and seal, this Ninth day of February, in the year of our Lord
Que thousand eight hundred and twenty-five
JOHN (L.S.) THOMPSON.

page_text: AND BE IT REMEMBERED, that on the Ninth day of February, in
the sixth year of the reign of His Majesty King George the Fourth, the
said John Thompson came before our said Lord the King in His Chancery,
and acknowledged the Instrument aforesaid, and all and every thing therein
5 contained and specified, in form above written. And also the Instrument
aforesaid was stamped according to the tenor of the Statute made in the
fifty-fifth year of the reign of His late Majesty King George the Third.
Inrolled the Ninth day of February, One thousand eight hundred and
twenty-five.