An Improved Apparatus for Oxidizing the Surface of Metals.
Year: 1888

page_text: Date of Application, 23rd June, 1888
Specification Accepted, 27th July, 1888
An Improved Apparatus for Oxidizing the Surface of Metals.
GEORGE WELTDEN GESNER of 45 Cliff Street, New York, in the County and State
of New York, United States of America, Consulting chemist and engineer, 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:-
The object of the invention is to treat metals, whereby a surface will be imparted
thereto, composed of an alloy or compound homogeneous with the body of the metal,
of a practically non-corrodible nature, and at the same time the ductility, toughness,
and tensile strength will not be diminished, without any material increase in the
dimensions of the articles, and without the formation of scale or film.
The invention consists of a retort or muffle, from which atmospheric air is excluded,
for holding the articles to be treated, and of a superheater arranged within or near
the retort and heated by the same fire, with connections between the two, whereby the
superheater is kept at the same or a higher temperature than the muffle.
In the accompanying drawings, Figure 1 represents a muffle with the superheater
inclosed within the same, with articles to be treated supported within the vertical
portion of the muffle. Figs. 2 and 3 are detail views of a form of superheater.
Heretofore in the treatment of metals-such as iron-the superheated steam used
has been conveyed to the retort or muffle from a superheater, independent of the
inuffle in which the articles were treated, and a serious objection arises to having the
superheater separate, for the reason that it is very desirable that the temperature of
the superheated steam and the muffle in which the articles are treated should be the
same, or at least that the superheated steam shall not be lower, and varied uniformly
in accordance with the temperature required for the treatment of different classes of
articles, and it is obvious that such uniformity of temperature cannot be obtained
where the two devices are separated and heated by different furnaces, the temperature
of the superheated steam, even though uniform in the superheater with the temperature
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page_text: of the muffle, losing in temperature in transit to the muffle. I have overcome this
difficulty by arranging my superheater within the muffle, or in such a position in the
bench as to be heated by the same fire which heats the muffle or muffles, and thus the
temperature in both the superheater and muffle will be uniform.
In Fig. 1 I have shown at A an ordinary form of muffle, from which the atmospheric
air is excluded, which, it will be understood, may be one of many within a bench.
The opening in the horizontal part of the muffle is provided with the ordinary mouth-
piece and lid, as shown. A suitable furnace is shown below the muffle, and this may
be fed with coal or liquid fuel, gases, or vapours in any well-known manner. A super-
heater, B, is shown as located upon the floor of the muffle, and may be of the form
shown or of any suitable construction. The steam pipe a, leading to it, may come from
any suitable source, such as a boiler or supplemental superheater. The particular form
of superheater represented within the muffle is shown in detail in Figs. 2 and 3. It
consists of a chamber in arched form, the steam from the boiler or supplemental super-
heater entering at the front wall, and after being superheated to the same temperature
as the retort passes out at the rear into the retort. I also use hydrocarbon oil or the
vapors of hydrocarbon, or both, in my process, and the pipe for the liquid or vapour
is represented at b. The arched form of superheater permits a branch, c, of the pipe b
to extend through the same, and the liquid hydrocarbon (if liquid be used) to be
partially vaporized in its passage, this pipe uniting with the pipe for the superheated
steam in the rear of the superheater and terminating in an upwardly-turned spraying
device, d. The articles to be treated are arranged within the muffle, either horizontally
or vertically, and are supported in such a manner as to expose the greatest amount of
surface to the action of the different agents used.
In Fig. 1 I have shown as one means of support, grate-bars having knife-edges,
providing ample support, and at the same time allowing the agents used to reach all
parts of the surface of the articles under treatment. It will be understood that many
modified forms of these devices may be used, varying according to conditions. The
hydrocarbon used may be, as I have before stated, either in liquid form or in the form
of vapour from a suitable vaporizer.
It will be understood that while I have shown in one figure the superheater as being
within the muffle, I do not limit myself to one superheater only, as others may be
located at any convenient place within the bench, it being necessary only that the
steam should be superheated by the same fire which heats the muffle and thereafter be
delivered upon the articles under treatment in the muffle at a uniform temperature
equal to that which is at that time required for the articles under treatment.
I have shown in Fig. 1 a pipe leading from the muffle to a hydraulic seal for
regulating the pressure within the muffle, and I connect the cap of this seal with a
pipe extending to the point of combustion of the furnace over the grate. A discharge
siphon-trap is connected with the hydraulic seal. When the pressure within the
muffle is ordinary, the gases escape through the pipe, passing upward, being cleansed
in the water of the seal, and through the connecting-pipe to the point of combustion,
where they are burned; but in case the pressure is excessive and the connecting-pipe
to the point of combustion not sufficient to carry them off, they are simply blown out
through the siphon. This automatic regulator saves the muffle from any injurious
effects caused by sudden increase of pressure.
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 the treatment of metallic articles, a retort or muffle for holding the article,
combined with an open-arched superheater arranged within the muffle, having
deflecting-plates arranged within the same to form a circuitous passage, pipe-connections
from said superheater to a boiler or other source of steam, and connections between the
superheater and muffle, substantially as described.
2. In the treatment of metallic articles, a retort or muffle for holding the article,
having a vertical and horizontal portion, a superheater arranged within the horizontal

page_text: portion, thereby leaving the vertical portion free for the article to be treated, pipe-
connections between said superheater and a steam source, and connections with the
interior of the muffle from the superheater, substantially as described.
3. In the treatment of metallic articles, a retort or muffle for the articles to be
treated, a superheater within the same, pipe-connections with a suitable steam source,
connections with the retort, inlet-pipes for the gases and hydrocarbon and a spraying
device connecting the various pipes within the muffle, said spraying device being
deflected upwardly to direct the agents directly against the articles treated, with
suitable cocks for regulating the flow through one or more of said pipes and cutting
it off altogether substantially as described.
HORN & SON,
Applicant's Agents.