Improvements in Electric Furnaces for Making Glass and other analogous Substances.
Year: 1899

page_text: Date of Application, 4th Dec., 1899-Accepted, 17th Feb., 1900
COMPLETE SPECIFICATION.
Improvements in Electric Furnaces for Making Glass and other
analogous Substances.
I, JOHANN LÜHNE, of No. 12, Maxstrasse, Aix-la-Chapelle, in the Empire of
Germany, 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 subject of the present invention is an electric melting furnace for
making glass, and other analogous substances.
This furnace consists of a melting-hearth A formed by the arrangement, in
a chamber a, of a number of voltaic arcs placed side by side in a longitudinal
direction and facing each other in a transversal direction; a tubular body with
square profile, or, in other words, a square prism with a longitudinal boring
right through it, constituting the negative electrode 1, opposite to which the
positive electrodes 2 and are ranged on both sides throughout the length of
the hearth.
A feed gear automatically regulates the combustion of the carbons or electrodes.
The positive electrodes are guided exactly by refractory bodies in the shape
of twyers with ribs, the particles of carbon falling from the electrodes being
conveyed to the exterior.
The prismatic shape of the negative electrode in the first place procures the
advantage of having the positive electrodes opposite a longitudinal sharp edge,
from which results an altogether modified combustion which favours the forma-
tion of the luminous arcs; moreover a uniform heating of the negative electrode
is obtained, from which result greater durability and more limited combustion,
and, finally, the negative electrode can be utilized by the four longitudinal
edges.
According to the strength of the current employed either cooling by insuffla-
tion of air or heating by insufflation of hydrogen gas can be obtained.
Insufflation of air is performed through the central longitudinal boring of
the negative electrode without the air passing through the small lateral per-
forations o, owing to the resistance to be overcome, and thus exerting no influence
on combustion. To insufflate hydrogen gas, not only is this perforation used,
closed in this case at one end, but also the little channels or lateral perforations o,
which lead into the central bore. Hot air can also be employed to heat the
electrode.
The fineness of the little perforations removes all fear of obstruction by
5 the melted mass, an undulatory formation of the lining c of the lateral walls
of the hearth chamber prevents the substance being melted from running
directly on to the various voltaic arcs (see Figure 2).
By the insufflation of hydrogen gas a greater length of the luminous arcs
is obtained and perceptible decrease of the tension is entirely avoided whilst
O with less powerful currents a greater power of emission is obtained by this
insufflation.
The chamber a has, besides its inner refractory lining c, a lining b which is
a non-conductor of heat and covers all the surface.

page_text: On account of the rapidity with which melting is produced, the substance
to be melted may be fed directly by an elevator which delivers it into a gutter
from which it falls into the hearth A, the entrance to which is regulated by
the regulator d which distributes the substance uniformly over the two sides
of the zone of fusion.
The melted substance falls into the channel f, which is in direct contact with
the zone of fusion, and thence flows through channel into the gutter B.
Conductors of the second class 4 and 5 are laid in the, bottom of this gutter B;
or a conductor of the second class could also be placed in the bottom of channel B,
extending the entire length of the said channel, so that the liquid mass falls
upon an incandescent surface and may flow into the cistern or into crucibles.
The conductors of the second class serve, then, to maintain the temperature
and are automatically regulated by the passage of the current.
For the manufacture of ordinary glass it will suffice to transform the gutter B
at its lower extremity into a tank or cistern of the requisite dimensions, in
which the melted mass can be kept at the desired temperature by a number of
conductors of the second class.
In order to be able to give the liquid mass any desired temperature, the mass
flows through the gutter B into a compartment C, passes over the raised edge
of the partition 7 into compartment E, and thence through channels 8 into
compartment F. Suitable amounts of gas charged with oxygen are introduced
to maintain the temperature of the mass and heat the tank; for this purpose
an in-take conduit G enters the pipe 9 from which the gases pass out through
opening 10.
The gaseous mixtures such as nitrogen protoxide, mixture of oxygen and
hydrogen, (atomized water or steam) or the like, passes through opening 10
into the tank and at first comes into close contact with the melted mass con-
tained in compartments C and E; channels 18 closed by valves 19 also enable
the gases to pass into compartment F in order that they may there also exert
their action. The charging channel m which is specially situated and com-
municates with channels 20 and 21, collects the gases disengaged by fusion of
the mass and by combustion of the gases introduced, and sends them through
channels 20 and 21 into channels 22 which latter run all around the tank and
from there they escape through the chimney 23.
The entire furnace consists then of the melting hearth A and tank W with
the central pipe 9 and the partitions or separating walls 11 and 7 which form
in the tank the compartments F, C, and E.
The top part W forms the cover or lid of tank W.
Around the tank W and its lid W there run the circular heating conductors M.;
these conductors are surrounded with a refractory covering or filling I protecting
the metal shells L and L' against the action of the fire.
The working apertures or mouths i can be closed by slides held up during
work by bolts 1, as shewn in the elevation Figure 3.
Channels 29 and 30 are constructed with a view to enable complete emptying
of the compartments C and F of the tank.
The entire furnace can be moved on rollers 24, but it can also be constructed
fixed, either with a tank or pots or crucibles.
As the melting hearth A supplies tank W with more melted material than
the workmen could work, it will be advantageous to combine two tank-furnaces
or pot-furnaces with a single melting-hearth; in which case a turn-out track K,
Figure 2, is established by aid of which a valve 27 directs the melted mass,
which descends by channel g into the respective gutter B leading into one
furnace or the other. For preliminary heating the tank W, it will be useful
to pour into it a very inflammable liquid fuel which burns without leaving a
residue, combustion of the said liquid being even further facilitated and accelerated
by the introduction of gas charged with oxygen.
In pot furnaces the melting hearth can also be situated directly over the

page_text: ompartment C of the tank, from whence the melted mass can be confected
ots.
TIL
Having now particularly described and ascertained the nature of my said
nvention, and in what manner the same is to be performed, I declare that what
claim is:
-
1. An electric furnace for making glass and other analogous substances,
characterized by the fact that the substances to be melted are brought to a state
of fusion in a chamber A, by the passage of a single or double zone of voltaic
ares, are collected in a channel f in direct contact with the zone of fusion and
that a channel B conveys this melted mass into a tank divided into compart-
ments, F, C, and E, by the partitions 11, & 7, compartment F being also
utilizable for work with the pot, substantially as described and set forth.
2. In an electric furnace for making glass and other analogous substances
as described, the arrangement of the melting hearth in such a way that the
negative electrode is formed of a tubular body with a square profile and having
lateral insufflation orifices serving to cool or heat the electrode, whilst positive
electrodes are arranged in rows all along the two opposite lateral edges of the
negative electrode, and direct access to the voltaic arcs is closed to the sub-
stances to be melted by an undulating formation of lateral walls of the melting
chamber, substantially as described and set forth.
3. In the electric furnace for making glass and other analogous substances,
such as described under Claim 1, the means for maintaining the temperature
of the melted mass after it has passed out of the hearth consisting of the arrange-
ment of conductors of the second class as incandescent bodies, and in compart-
ments of the tank, the arrangement either of conductors of the second class or
of a pipe to admit oxygen charged gases, as for example nitrogen protoxide, or
mixtures of oxygen and hydrogen (atomised water) or again both the arrange-
ment of conductors of the second class in addition to pipes to admit the gases
charged with oxygen, substantially as described and set forth.
( ) 4. In the electric furnace for the manufacture of glass, and other analogous
substances as described under Claim 1, the combination of a single melting
hearth with several tanks, a suitable system of inverting K, enabling running
of the melted mass, flowing from the melting hearth, through a valve 27,
alternately into one or the other of the tanks, substantially as described and
5 set forth.
ד
11800
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.