IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL, AND IN APPARATUS THEREFOR
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office of
the Commissioners of Patents on the 27th May 1878. A communication from
abroad by David Thomas, of Saint Louis, Missouri, United States of America,
Puddler.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
IRON AND STEEL, AND IN APPARATUS THEREFOR." [A communication from abroad..
by David Thomas, of Saint Louis, Missouri, United States of America, Puddler.]
The present Invention relates to an improved process for readily and cheaply
manufacturing a soft, pure, homogeneous iron, in character resembling Norway iron,
and a strong, pure, homogeneous steel, similar to crucible steel, and to the means
preferably used in this process, which is substantially as follows:-
The said process consists in melting wrought iron and cast iron combined in
suitable proportions with charcoal or other carbonaceous fuel until the compound
(that is to say, of wrought and cast iron) is thoroughly melted and brought into the
condition of a molten mass. A very hot air current (preferably at a temperature of
3500° or 4000° F.) is then passed through all parts of the molten mass, and meanwhile
the outer atmosphere is carefully excluded, and suitable chemicals, such as lye,soda ash,.
manganese, and salt, are introduced into the molten mass. This subjection of the
molten mass to the influence of the heated air is continued for, say, 15 to 45 minutes,
when the metal becomes purified to a remarkable degree, and thus steel (or wrought
iron, as the case may be) of a very superior quality is readily produced.
A desirable apparatus for effecting my object is as follows:-A furnace is placed
on posts, and is open at the top to receive the charge, and to allow the products of
combustion to pass off; but instead of allowing the latter to pass directly off into
the open air they are first made to return from the furnace top downward, and
around the outside of the furnace, thence to escape into a flue or flues. For this
purpose the furnace proper is enclosed above and at its sides by a casing, which
rests upon an annular plate that closely surrounds the furnace, and that in turn is
supported by posts.

page_text: The said casing in diameter is large enough to form an annular space around the
furnace, which space serves as a flue to carry off the products of combustion. An
exit flue leads from the said space or flue, through which the products of combus-
tion finally escape to the open air. By thus enclosing the principal portion of the
furnace, and causing the products of combustion to circulate around it before
escaping to the open air, the furnace is not only kept very warm, but the outer air
is effectually prevented froin entering the furnace, and unfavorably affecting the
character of the metal being made therein.
The furnace proper immediately outside the casing is walled about with fire-brick
that rests upon the aforesaid plate, and the casing is composed chiefly of fire-brick
contained in a shell.
The hot-air blast may be produced in any desirable manner. I preferably however
utilize the said annular space as an oven, and, by causing a pipe to wind around
therein before entering the furnace, take advantage of the heat escaping from the
furnace to heat the air.
The said pipe is carried up and down and around in the said space until finally
it is made to encircle the furnace. From this pipe two series of tuyeres lead into
the furnace.
The furnace is charged in the following manner, that is to say:-A mixture of
wrought and cast iron, together with charcoal, is put into the furnace through the
doorway, which, excepting when the furnace is being charged, is kept closed by the
door. The charge comes under the influence of the hot-air blast, entering through
the upper tuyeres, and is brought into a molten condition. It falls or sinks as a
molten mass, encountering the hot-air blast entering the lower tuyeres. This
last-named blast operates to intensify the heat of the molten bath, and to increase
the fluidity of the same.
While the molten metal is under the influence of the blast suitable chemicals,
such as concentrated lye, soda ash, manganese, and salt are introduced into the
molten metal.
I use for making iron about one ounce of each to 100 lbs. of metal, and for making
steel a larger quantity of lye and manganese.
If desired a third series of tuyeres, arranged at a still lower level, can be:
employed.
The tuyeres are furnished with slides to enable the chemicals to be introduced.
into the furnace through the same.
The lower part of the furnace is lined with blacklead to protect it from the
heat.