An Improved Process and Apparatus for Preventing the Access of Air to Iron and Steel During Annealing.
Year: 1890

page_text: Date of Application, 17th May, 1890-Accepted, 21st June, 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by GEORGE WYCKOFF CUMMINS, of Vienna, County of
Warren, State of New Jersey, United States of America, Student.]
An Improved Process and Apparatus for Preventing the Access of
Air to Iron and Steel During Annealing.
1, HENRY HARRIS LAKE of the firm of Haseltine Lake and Company, Patent Agents,
Southampton Buildings 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 a process and apparatus for preventing the access of
atmospheric air to iron and steel while being annealed.
The accompanying drawing shows an entire plant for carrying out this invention.
A indicates two similar covered vessels or annealing pots for containing the iron or
steel to be annealed; and B indicates a larger vessel, such as an ordinary annealer
within which the pots A are contained. Opening into the annular space between the
vessels A and B, is an inlet pipe C. The vessel B is set within masonry or brick
work D, over a furnace F, having a fine G, for the exit of its products of combustion.
The vessel B, is fitted with a cover H, and over the annular furnace space, F, between the
vessel B, and the walls of the masonry is fitted an external cover I. Within the same
masonry is built a cylindrical chamber K, having an inlet pipe L near its bottom, and
a top or cover M.
The mode of operation of this invention and the rationale of the process will now be
described.
Ordinarily during the process of annealing in closed vessels oxidation occurs in two
ways; by the action of the oxygen in the vessel around the metal and by the entrance
of oxygen from without into the annealing vessel by diffusion and by the contraction
of the contained gases when cooling.
It is the purpose of this invention to prevent the entrance of air into the
annealing vessel and thus prevent the greater part of the oxidation that now
occurs.
This is accomplished as follows :-
-
The iron or steel to be annealed is placed in one, or both, of the vessels A, which
are as tight as may be, and the vessels then placed with the contained iron or steel
within the larger vessel B, the ordinary annealer. There is then passed into the
outer vessel through the tube c, a gas that is incapable of oxidising iron, such as
hydrodgen, nitrogen, or such gas as may be made by passing air over charcoal or
other carbonaceous material. This gas is kept passing into the vessel B continuously
while the metal is heating and cooling in the inner vessel, or vessels A.
When these
two vessels (or one vessel if only one be used) with the iron or steel therein are
heated up, the air therein is expanded and a portion of it is accordingly expelled
therefrom. The oxygen of the remainder combines with the grease which is always
on the iron or steel if it be wire, or else unites with the iron or steel directly forming
however but a small amount of oxide. The only gaseous material that can gain
access to the metal in the vessels A is then the gas contained in the vessel B
and as this is a nonoxidizing gas the iron or steel when cooled is bright and
not oxidized.
The advantage that this process offers over passing the non-oxidizing gas directly
into the vessels A, is that less care is required in the selection of a suitable gas and
that far better results can be obtained by a given gas.
The cylindrical chamber K, is provided as a slow cooling-chamber for the vessels A,
which it will accommodate either singly or together. The object of making the
vessels A so that two can be used together is for convenience of handling. If one

page_text: vessel A were made large enough to properly fill the vessel B, it would be too large to
lift in and out, but would make no difference in the annealing operation, except to
take more time to operate the plant, as- the cooling-chamber. K could not be used.
But with smaller vessels A as soon as sufficiently heated said vessels may be trans-
ferred to the cooling-chamber K, and there allowed to slowly cool, while the furnace F,
is allowed to heat up other vessels similar to the vessels A, and thus a succession or
round of operations may be continuously carried on. During the cooling of the
vessels A in the chamber K, gas is kept continuously passing into it through the
pipe L.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
:-
First. In the annealing of iron and steel the process of preventing the access of
atmospheric air thereto, consisting in inclosing the same in a closed vessel and
inclosing this vessel within a larger one, and keeping the space between said vessels
filled with a non-oxidizing gas, substantially as and for the purposes set forth.
Second. The combination with an internal vessel, or vessels, A, of an external
vessel B, provided with a gas-inlet pipe c, for annealing iron and steel, constructed
and operating substantially as described for the purposes set forth.
Dated this 13th day of May 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.