Improvements in the Manufacture of Glass and other Analogous Substances, and in Apparatus therefor.
Year: 1899

page_text: Date of Application, 1st Dec., 1899-Accepted, 23rd June, 1900
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Glass and other Analogous
Substances, and in Apparatus therefor.
I, JOHANN LÜHNE, of Maxstrasse 12, 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 present invention relates to improvements in the manufacture of glass
and other analogous substances, such for example as crystal and in apparatus
therefor; the main objects of it being to prevent decomposition and to more
perfectly refine the substance under treatment when in the molten state.
An essential condition for the manufacture of refined glass, particularly of
the glass employed in optics, is not only to obtain very pure glass, perfectly
colourless, transparent and refringent, but also perfect uniformity in the
structure of the glass.
The difficulty of obtaining a uniform composition resides in the difference
of specific gravity of the different silicates which tend to deposit themselves in
the tank in layers corresponding to their gravity and thus cause production of
a non-homogeneous glass. It is, therefore, requisite to employ the greatest care
during fusion and during the refining of the product to be obtained and care-
fully prevent decomposition of the liquid masses.
_
Application of the present process gives the following advantages:-
1. Radical and intimate mixture of the liquid mass can be obtained by aid
of the bell D) which prevents decomposition of the mass.
2. The flanged edge of the bell D which descends far below the level of the
liquid mass, causes in this latter a great circulatory movement, so that the forma-
tion of layers in the tank is entirely avoided.
3. This forced circulation of the liquid mass below the edge of the bell I
causes at the same time separation of the impurities by a syphon-shaped
shutter.
4. The introduction, exceedingly important in glass-making, of gases charged
with oxygen is very advantageously concentrated by the bell D on the liquid
mass.
Figure 1 of the accompanying drawing represents the apparatus necessary
for application of the new process of refining with a bell D worked by mechanical
means whereas in the apparatus represented by Figure 2, this bell is fixed.
The melted mass descends by the channel B, in which the impurities floating
on its surface are taken off by a device 6, and enters compartment C from
whence it passes over the edge of partition 7 into the compartment E and from
there, through channels 8, into compartment F. The device 6 consists of a
trap-door or oscillating shutter suspended in such a way that the mass which
descends into channel B raises it and that it collects by its opening the
impurities which float on the surface of the liquid mass. One takes off these
impurities according to requirements. This shutter also prevents the escape
of the gases from the tank by the channel B.

page_text: Before passing from the compartment C over the partition 7 into the com-
partment the liquid mass is worked by the bell 1) suspended from the point H
in a suitable support 25. Not only can the bell move upwards and downwards
but it can also be made to rotate like an agitator or stirrer.
Even when at rest the bell I could cause with its edge 12 prolonged towards
the base, a sharp circulation of the mass passing from the compartment C into
the compartment E and thus make it homogeneous.
In addition to the mechanical, regular and thorough mixing which is essen-
tial to assure a good quality of the product to be manufactured, employment
of the bell D also offers a perfect guarantee against all conveyance of impurities
from the compartment C into the compartment F, by forming a syphon-shaped
shutter.
The solidity of the bell D) is assured by a perforated metal centre-piece 13
which is suspended by the rod 14 and the perforations of which permit joining
of the masses of clay separated by the metal centre-piece.
In order to assure a suitable admission of oxygen or gases charged with
oxygen, the employment of which is necessary for proper treatment of the
melted mass, these gases are introduced under the bell D by the pipe 9 situated
at the bottom of the tank but which might also be placed in a horizontal
position.
The gases charged with oxygen which arrive through the orifice 10 of the
pipe 9 firstly enter under the hell 1) into uniform contact with the melted mass
contained in the compartment E; they then pass through the small lateral per-
forations of the bell 1) into the compartment C where they also come into
close contact with the melted mass therein contained and, if necessary, one can
make them pass into the compartment F through the channels 18 furnished
with valves 19 in order there also to exert their action. The upper hermetic
joining of the bell D is assured by the bell 16 dipping into a circular channel 15
filled with a liquid not easily evaporated. The rod 14 of the bell D is guided
in the guide-bar 17. The outlet channels 20, 21, and 22 collect the gases dis-
engaged in the tank and conduct them around the tank W and its lid W, in
order to maintain their temperature, conveying them to the discharge chimney 23.
The finished product is taken out through the orifices i. G forms the junction
pipe for adduction of the gases which serve to maintain the temperature.
In the structural modification represented by Figure 2, the bell I forms part
of the top of the furnace; the lower part or tank W is separated by the
partitions 11 and 7 to form compartments C, E and F, and the channels S
establish communication between compartments E and F. All around the
furnace there are orifices which can be shut by slides K and through which
the workmen take out the melted and refined mass.
This process of refining can not only be utilised in electric-melting furnaces,
but also be employed for all kinds of
gas furnaces.
In this case the melted
mass is introduced through the vertical channels m running into compartment C.
For employment of gas the admission pipe 9 can be retained and the gases
which are disengaged can pass out in the same way as in the preceding structure.
Instead of introducing the gases by the vertical pipe or horizontal pipe 9,
one could also make them enter by the top of the fixed hell D, Figure 2. Purge
conduits 29 and 30 enable one to empty the compartments of the tank.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
1 claim is
1. A process to prevent decomposition and produce refining, of masses of
liquid glass, a process characterised by the fact that a shutter D, preferably
constructed in the shape of a bell produces, either at rest or in consequence of
its mechanical motions, a close and radical mixture of the melted mass and thus
prevents the decomposition, at the same time separating the impurities of the

page_text: liquid mass owing to the forced circulation of this last under the edge 12 of
the bell 1) which dips deeply below the level of the mass and forms a syphon
shutter, whereas this bell D also assures good distribution of the gases charged
with oxygen utilized to maintain the temperature, substantially as described and
set forth.
2. In the structural arrangements described under Claim 1, the admission of
gases charged with oxygen either from top to bottom by the fixed shutter D,
in form of a bell or by the horizontal or vertical pipes 9,. substantially as described
and set forth.
3. The process described under Claim 1, completed by this, that a trap or
hollow body placed in the channel B collects by its orifice the impurities
which float on the surface of the liquid mass and at the same time prevents
escape of the gases through channel B, substantially as described and set
forth.
1
1000
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.