An Improved Method of and Apparatus for Obtaining High Tempera- tures for Smelting Metals and other like purposes.
Year: 1899

page_text: Date of Application, 20th Mar., 1899-Accepted, 13th May., 1899
CUMPLEIE SIEVITICATION
An Improved Method of and Apparatus for Obtaining High Tempera-
tures for Smelting Metals and other like purposes.
I, WILHELM BORCHERS, of 3, Lousberg Strasse, Aix la Chapelle, in the German
Empire, Professor of Metallurgy, 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, reference being had to the accom-
panying drawings and to the letters and figures marked thereon, that is to say:-
This invention relates to an improved method of and apparatus for obtaining
high temperatures for smelting metals and other like purposes.
Attempts have been made to obtain very high temperatures by combustion
by the employment of gas heating apparatus in connection with heat regenerators,
but for well known reasons such apparatus rarely permitted of a temperature
of 2000° C. being exceeded. Higher temperatures, can in a reliable manner,
only be obtained by the combustion of solid carbon in such a manner as to directly
form carbonic oxide.
Moreover for raising natural temperatures of combustion preliminary heating
of the fuels and of the air has been employed, whilst it is known, that by the aid
of oxygen or of gas mixtures rich in oxygen, a similar object may be attained.
Lastly an increased rate of combustion by the use of compressed air is another
means for obtaining the desired result.
The furnace hereinafter described is intended to serve for the practical carrying
out of all three means above referred to; but is more especially intended for the
indispensible preliminary heating of the solid fuel, coke, or char-coal which
operation, as is known has heretofore been a matter of difficulty. For this pur-
pose the fuel employed is caused to serve at the same time as the heat accumulat-
ing material.
Reference being had to the accompanying drawings:
Fig. 1 represents a vertical longitudinal section of my improved furnace;
Fig. 2 is a side elevation of the same.
Fig. 3 is a horizontal section on the line A B of Fig. 1;
Fig. 4 is a section taken through the draft regulating damper, the arrangement
of which is seen in Fig. 2;
Fig. 5 shows one form of damper, which may be of any known construction,
for closing the feed hopper.
In Fig. 1, o o represent two iron lined outer shafts or chambers of fire-proof
material, which serve alternately as combustion chambers and heat accumulators.
The fuel is supplied to these chambers respectively by feed hoppers t. Between t
and the cover m a free space is left, through which the waste gases from the
furnace can be carried off. For the admission of air or oxvgen nozzles d worked
alternately and protected by water-jackets or cooled mountings are provided.
Between the two chambers is a shaft or passage g (seen in the drawings) which
is provided with two closing devices for preventing the escape of gas there-
through. The hoppers are also kept closed by the damper device or register
317

page_text: plate such as shown in Fig. 5. is a collecting box or receptacle for the solidified
products, which are to cool therein and from which the air is excluded. I are
cooling passages for protecting the masonry at the hottest places of the furnace.
Into the gas discharge pipes, which join the cover m (see Fig. 2), is inserted a
Tshaped pipe having a valve w capable of being turned up or down.
The operation is as follows;
According as the fuel is coarse or fine, the chambers o, o², are filled either
partially or entirely. The fuel is lighted through the ignition holes and is,
at first allowed to burn undisturbed with the hoppers open. After the furnace
has thus been preliminarily heated to a sufficient degree, and the lower layers
of the fuel have become sufficiently incandescent, both chambers are then charged
with fuel to the desired height and the feed hoppers are closed. The charge to
be smelted is then admitted through the central shaft g, and air or oxygen is
blown into one of the outer shafts, for instance o¹, the air or oxygen, being
delivered through a suitable pipe or conduit. The other shaft is arranged to
simultaneously communicate with the gas discharge pipe, by the three way-valve w.
After the ignition holes have been closed, (say by clay plugs,) the hot gases of
combustion pass through a transverse chamber or passages from the chamber o
to the chamber 02, and while the combustion and the generation of heat take
place in the chamber o, the heat that has not been consumed in the chamber s
accumulates in the fuel in the other chamber o², as the gases of combustion are
compelled to pass off through the latter.
After a short time, the valve is reversed and the air or the oxygen, as the
case may be, is blown in at d, whereby the gases of combustion are compelled to
pass off through the fuel accumulated in o' thereby heating the said fuel.
It is evident, that in this manner, the temperature in the furnace will soon
attain the highest possible limit. It is clear moreover that this temperature will
be higher than in the case of furnaces heated by gaseous fuels, for in the latter,
on account of the low. temperature at which the products of combustion (CO,
and H) become dissociated it is not possible to greatly exceed a temperature
limit of 2000° C. On the other hand, there is nothing in the way to prevent the
combustion of the carbon being effected as is intended in this furnace, partly by
a suitable preliminary heating of the carbon, partly by enriching the air with
oxygen, and partly by the possibility of operating under pressure. In fact carbon
is still consumed at temperatures beyond 3500° and although it only forms car-
bonic oxide there is still a sufficient development of heat for the purposes for
which the furnace is designed.
In order to remove the molten products from the chambers the upper closing
lid of the box is opened, wooden or carbon rods being inserted through each of
the openings to prevent undecomposed portions of the charge from slipping out
after the said products. The openings also enable the smelting process to be
watched. The finished product first descends into the box, the upper lid of
which is at once re-closed and after it has cooled down, the contents of said box
are discharged through the bottom door or flap.
As in these high temperatures the ashes of the fuel will accumulate in a molten
state in the chambers, 2, the firing holes already referred to, are provided.
through which the ashes can be discharged, after the clay plugs have been
removed.
To prevent these clay plugs from being forced out, if compressed air is employed,
they are weighted by heavy iron presser rods as seen in Fig. 1.
The process as well as the apparatus are applicable first for heating all sub-
stances which, in order to be reduced require a higher temperature than could
be obtained by former methods of heating and secondly, in cases where the
products of combustion such as carbonic acid (CO) and wet steam (H₂O) have an
injurious effect upon the smelting products.
Obviously under the working conditions above described, and by utilizing

page_text: carbon alone as fuel, the gases of combustion will be obtained in a form approxi-
mately free from carbonic acid. Moreover instead of only a single outer chamber
at each side of the furnace there may be two or more as desired.
two
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that what I claim is;----
1. The method of obtaining high temperatures for smelting metals and like
purposes which consists in producing the heat alternately in one of
chambers, or in one of two groups of chambers, filled with
solid preliminarily heated fuel by the combustion of the latter, with-
out the employment of heat regenerators or recuperators, while the
fuel in the other chamber, or other group of chambers, is directly heated
by the gases leaving the smelting chamber, without employment of heat regener-
ators or recuperators, and in then using the fuel in the second chamber, or second
group of chambers, for the production of the smelting temperature by the direct
combustion of the solid preliminarily heated fuel, while the fuel in the first
chamber, or first group of chambers, serves for the accumulation of the heat of
the waste gases, without the employment of heat regenerators or recuperators,
substantially as set forth.
2. For carrying out the method referred to in the preceding claim, the apparatus
hereinbefore described with reference to the accompanying drawings.
141 50th ....
1000
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, & 5A, Market Street, Nottingham,
Agent for the Applicant.