IMPROVEMENTS IN THE EXTRACTION OF GASES FROM MOLTEN METALS
Year: 1879

page_text: LETTERS PATENT to Russel Aitken, of Great George Street, in the City of
Westminster, for the Invention of "IMPROVEMENTS IN THE EXTRACTION OF
GASES FROM MOLTEN METALS."
PROVISIONAL SPECIFICATION left by the said Russel Aitken at the
Office of the Commissioners of Patents on the 5th June 1879.
RUSSEL AITKEN, of Great George Street, in the City of Westminster. “IM-
PROVEMENTS IN THE EXTRACTION OF GASES FROM MOLTEN METALS."
This Invention relates to methods of improving the qualities of metals by
extracting when in a molten state the gases which may be occluded in them.
In carrying out my Invention the inolten metal from which it is proposed to
extract the occluded gases is placed in a ladle or trough, or it may, if it be Bessemer
steel, remain in the converter, and on the top of this ladle, trough, or converter I
place a cover which is made air tight; I then by pipes or other-wise connect the
space over the molten metal with exhausting air pumps, or otherwise make a
vacuum more or less perfect over the molten metal, so that the air occluded or shut
up in metal will expand, and so be run over from it. Another method of effecting
the same object will be to enclose the ladle, trough, crucible, or Bessemer converter
containing the molten metal in a box or chamber from which the air can be
extracted, or it may be found advantageous to carry out the whole or part of the
Bessemer process of steel making in a partial vacuum chamber. The vacuum may
be produced by air pumps or in any of the usual modes, and when the molten
metal is in partial vacuum, I may pass through the metal such gases as I may find
improve or alter the quality of the metals treated; and I may also use solids or
liquids for the same purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Russel Aitken in the Great Seal Patent Office on the 3rd December
1879.
RUSSEL AITKEN, of Great George Street, in the City of Westminster.
PROVEMENTS IN THE EXTRACTION OF GASES FROM MOLTEN METALS."
" IM-
My said Invention relates to methods of improving the qualities of metals by
extracting when in a molten state (that is to say, in any state in which the metals
may exist between a solid and fluid condition) the gases which may be occluded in
such metals.
According to one mode of carrying out my Invention, the molten metal from
which it is proposed to extract the occluded gases is placed in a ladle or trough, or
in the case of steel, it may be poured into ingot moulds, or if it be Bessemer steel,
it may remain in the converter, and on the top of this ladle, trough, ingot mould,
or converter; I place a cover which hermetically closes the vessel; I then by pipes or
otherwise connect the space over the molten metal with exhausting air pumps,
or otherwise make a vacuum more or less perfect over the molten metal, so that the
gases occluded or shut up in the metal will expand, and thus rise and leave the
metal nearly free from gas, thereby producing metal of a close homogeneous
character. In treating steel in ingots by this process it is desirable that the mould
should be heated before the metal is poured into it.
According to another mode of carrying out my said Invention, I effect the same
object by enclosing the ladle, trough, crucible, ingot mould, Bessemer converter, or
other vessel containing the molten metal in a box or chamber in which a vacuum
may be produced, and thus the gases in the metal bo extracted.
According to a further mode of carrying out my Invention, I run the metal
when in a molten state through a syphon, the legs of which are of sufficient length
to give the required vacuum at the top or bend of the syphon, and I draw off the
gases disengaged from the metal at the top or bend of the syphon by an air pump
or other means.
Or the chambers in which the metals are heated or melted may be so constructed
as to admit of their being made air tight after the metal has been heated or melted,
and then the exhaust being applied the gases may be extracted from the heated or
liquid metal, which may then be taken out and used.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that I am aware that it has been previously
proposed to cast certain articles in vacuo, and therefore to this arrangement I lay
no claim, but what I consider to be novel and original and therefore claim as the
Invention secured to me by the hereinbefore in part recited Letters Patent is,—
Extracting gases from molten metal while such metal is contained in a ladle,
trough, crucible, converter, or other vessel before being run into the ingot mould
or other mould; or when in the steel ingot mould, by subjecting such inetal to the
action of a vacuum or exhaust, substantially as and for the purpose hereinbefore
described.
In witness whereof, I, the said Russel Aitken, have to this my Specification
set my hand and seal, this Twenty ninth day of November, One thousand