Improvements in Apparatus for Converting Crude Iron into Malleable Iron or Steel.
Year: 1888

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Converting Crude Iron into
Malleable Iron or Steel.
1, JOHN WESLEY BOOKWALTER, of Springfield, Ohio, United States of America,
Engineer at present residing at the First Avenue Hotel, Holborn in the County of
Middlesex, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to improvements in convertors of the Bessemer type and the
object thereof is to secure as complete a circulation as possible of the molten metal
which is acted upon by the air blast so that every portion of the metal may come in
contact with it and at the same time avoid producing such agitation on the surface and
such currents in the body of the metal as will cause the scoria and other impurities to
be drawn into and mixed with the liquid metal.
Referring to the accompanying drawings in which like letters of reference represent
like parts,
Fig. 1 is a vertical section of a convertor and Fig. 2 is a horizontal section on line ab
of Fig. 1..
The convertor A is constructed in the usual manner the form illustrated being
provided at the bottom with an air chamber B through which the blast is conducted
to the tuyeres. In the centre of the convertor is a vertical shaft C composed of or
surrounded by fire clay or other refractory material: This shaft is closed at the top
and lateral openings are formed permitting the air to escape centrifugally and act
upon the molten metal at the surface or a short distance below. These openings or
tuyeres give a direction to the blast or jet of air horizontal or nearly so, but they
may be inclined at a small angle either -upwards or downwards to the horizontal
plane. The openings may also be so formed that they will impart a direction to
the blasts or jets of air at an angle to a radial line drawn from the centre of the
convertor to the periphery. The effect of this arrangement of the tuyeres will be to
give the metal in the convertor a horizontal rotary motion about the perpendicular
axis of the convertor. The motion of the air towards the outer circumference of
the mass of metal will also give the upper portion of the metal a motion from the

page_text: centre of the mass radially outwards towards the wall of the convertor and will' cause
the metal to rotate in a vertical plane the combination of these two motions producing
a resultant motion which will ensure the exposure in due time of every particle of
metal to the blast. As the air acts upon the metal near the surface and does not
penetrate into the body of it all the impurities generated are at or near the surface
and are by the force of the blast driven to the outer portion of the metal where they
remain floating on the surface near or in contact with the inner surface of the wall of
the convertor. Instead of using separate tuyeres a single annular opening may be
employed which would deliver a circular sheet of air blast; or instead of being circular
the shape of the head and opening may be varied to suit the shape of the convertor.
If the tuyeres C¹ be disposed only radially and not tangential the circulation of the
metal would be chiefly or entirely vertical and not horizontal and in most cases
this would be sufficient without the horizontal circulation especially if the single
opening be used.
The shaft C may project upwardly from the bottom or downwardly from the top or
may even project from the side of the convertor the discharge in all cases being from
the tuyeres towards the wall or walls of the convertor. To keep the tuyeres at the
proper level as the surface of the metal falls during the conversion owing to the climi-
nation of the impurities the head which contains them may be made movable so that
it can be caused to follow the fall of the metal.
A convenient way of carrying this into effect would be to make the shaft C telescopic
the portion having the openings or tuyeres being raised or lowered by an internal rod
passing up through the interior of the shaft C.
It must be understood that although I have shown my invention as applied to a pear-
shaped convertor in which the blast is admitted vertically yet the improvements are
applicable with suitable modifications to any of the ordinary forms of convertors
whether fixed or tilting.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what. I
claim is:
1. In a convertor a vertical shaft such as C having a lateral opening or openings to
discharge the blast at or near the surface of the metal and in a horizontal or approxi-
mately horizontal direction substantially as and for the purpose described and illustrated
in the accompanying drawings.
2. The employment in a convertor of a series of tuyeres arranged radially or nearly
so at or near the centre of the molten metal contained in the convertor and delivering
the blast to the metal at or near the surface in such manner that the impurities
generated or liberated in the process of conversion shall by the action of the air
blast be thrown towards the outer circumference of the mass of the metal upon the
surface of which they will rest in a state of practical separation from the metal in the
bath substantially as and for the purpose described.
3. The combination with a convertor of one or more tuyeres adapted to deliver a
centrifugal blast horizontally or nearly, so at or near the surface of the. metal
substantially as and for the purpose described.
Dated this 9th day of May 1888. ·