U.S. patent application number 17/095893 was filed with the patent office on 2021-05-13 for apparatus for the automated production of glass assemblies and corresponding method.
The applicant listed for this patent is Endress+Hauser Conducta GmbH+Co. KG. Invention is credited to Carsten Enderwitz, Jens Voigtlander, Roland Zilly.
Application Number | 20210139363 17/095893 |
Document ID | / |
Family ID | 1000005273645 |
Filed Date | 2021-05-13 |
![](/patent/app/20210139363/US20210139363A1-20210513\US20210139363A1-2021051)
United States Patent
Application |
20210139363 |
Kind Code |
A1 |
Enderwitz; Carsten ; et
al. |
May 13, 2021 |
APPARATUS FOR THE AUTOMATED PRODUCTION OF GLASS ASSEMBLIES AND
CORRESPONDING METHOD
Abstract
An apparatus for the automated production of glass assemblies
comprises: a turning machine with at least two spindles which are
rotatable about a common axis of rotation and which each have a
workpiece holder, wherein the workpiece holders are arranged
opposite one another; one or more gas burners or lasers fixed on a
first tool carriage which is movable in parallel and/or
perpendicularly to the axis of rotation; one or more drives for
driving a rotational movement of the spindles and a movement of the
first tool carriage; a pressure module including a pump device at
least one working cylinder for applying a pressure to an inner tube
and/or to a space between the inner tube and an outer tube; and a
control unit configured to control the burners or lasers, one or
more drives, the first tool carriage and the pressure module.
Inventors: |
Enderwitz; Carsten;
(Dresden, DE) ; Zilly; Roland; (Jahnsdorf, DE)
; Voigtlander; Jens; (Waldheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Endress+Hauser Conducta GmbH+Co. KG |
Gerlingen |
|
DE |
|
|
Family ID: |
1000005273645 |
Appl. No.: |
17/095893 |
Filed: |
November 12, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C03B 9/3636 20130101;
C03B 23/045 20130101; G01N 27/36 20130101; C03C 23/0025 20130101;
C03B 23/07 20130101; C03B 23/055 20130101; C03B 23/043 20130101;
G01N 27/4167 20130101; C03B 9/41 20130101 |
International
Class: |
C03B 23/07 20060101
C03B023/07; C03B 23/055 20060101 C03B023/055; C03B 23/043 20060101
C03B023/043; C03B 23/045 20060101 C03B023/045; C03B 9/41 20060101
C03B009/41; C03B 9/36 20060101 C03B009/36; C03C 23/00 20060101
C03C023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2019 |
DE |
10 2019 130 477.6 |
Claims
1. An apparatus for the automated production of glass assemblies,
each of which includes an outer tube and an inner tube extending
inside the outer tube, wherein the inner tube and the outer tube
are arranged coaxially, and wherein one end of the inner tube is
connected in a firmly bonded manner to a tube wall of the outer
tube, the apparatus comprising: a turning machine including at
least two spindles which are rotatable about a common axis of
rotation and which each have a workpiece holder, wherein the
workpiece holders are arranged opposite one another; one or more
gas burners or lasers fixed on a first tool carriage which is
movable in parallel and/or perpendicular to the axis of rotation of
the spindles; one or more drives adapted to drive rotational
movement of the spindles and movement of the first tool carriage; a
pressure module comprising a pump device configured to apply a
pressure to the inner tube and/or to a volume between the inner
tube and the outer tube, wherein the pump device includes at least
one working cylinder; and a control unit configured to control the
burners or lasers, the drives of the spindles, the first tool
carriage and the pressure module.
2. An apparatus of claim 1, wherein the pressure module includes a
pressure sensor, and wherein the control unit is configured to
execute a regulation of the pressure in the inner tube and/or in
the space between the inner tube and the outer tube to a target
value using the pressure sensor and the pump device
accordingly.
3. An apparatus of claim 1, wherein the pressure module includes an
opening valve adapted to enable rapid opening and discharging of
the pressure in the inner tube and/or in the space between the
inner tube and the outer tube.
4. An apparatus of claim 1, further comprising a second tool
carriage which is movable in parallel and/or perpendicular to the
axis of rotation of the spindles and on which a camera is disposed,
the camera connected to the control unit as to communicate digital
image data to the control unit.
5. An apparatus of claim 1, wherein the working cylinder comprises
a piston rod enabling movement back and forth.
6. An apparatus of claim 1, wherein the working cylinder is a
pneumatic cylinder, a hydraulic cylinder or an electric
cylinder.
7. An apparatus of claim 1, wherein the working cylinder includes a
rotary encoder.
8. An apparatus of claim 1, wherein at least one workpiece holder
includes a seal.
9. An apparatus of claim 1, wherein at least one workpiece holder
is configured to be movable in a direction of the other workpiece
holder.
10. An apparatus of claim 1, further comprising a tool configured
to shape the outer tube, the tool arranged on a third tool carriage
which is movable in parallel and/or perpendicular to the axis of
rotation of the spindles.
11. A method for the automated production of glass assemblies,
wherein the glass assemblies each have an outer tube and an inner
tube extending inside the outer tube, wherein the inner tube and
the outer tube are arranged coaxially, and wherein one end of the
inner tube is firmly bonded to a tube wall of the outer tube, the
method comprising: providing the apparatus of claim 1; assembling a
glass body comprising an outer tube and two inner tubes, each
arranged inside the outer tube and arranged one behind the other
coaxially to an axis of rotation of the outer tube, wherein the
inner tubes are each firmly bonded manner to the outer tube at an
end adjacent the respective other inner tube; and applying a
pressure to the inner tubes and/or to a space between the inner
tubes and the outer tube, wherein the method is performed
automatically using the control unit.
12. The method of claim 11, further comprising splitting the glass
body into two separate glass assemblies.
13. The method of claim 12, further comprising: recording image
data of the glass body; and controlling the assembling of the glass
body, the applying of the pressure, and/or the splitting of the
glass body using the recorded image data.
14. The method of claim 11, further comprising regulating the
pressure in the inner tube and/or in the space between the inner
tubes and the outer tube to a target value.
15. The method of claim 11, further comprising moving at least one
workpiece holder in a direction of the other workpiece holder for
drawing or compressing the glass body.
16. The method of claim 11, further comprising shaping the outer
tube using a tool.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is related to and claims the
priority benefit of German Patent Application No. 10 2019 130
477.6, filed on Nov. 12, 2019, the entire contents of which are
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an apparatus for the
automated production of glass assemblies and to a corresponding
method.
BACKGROUND
[0003] A potentiometric pH sensor for detecting the pH value of a
measuring liquid by means of a pH-sensitive glass electrode
typically comprises a glass assembly with two coaxially arranged
glass tubes, wherein the outer glass tube is connected at one end
to the inner glass tube so that the outer glass tube is closed at
this end. In a pH sensor with a glass electrode, the inner glass
tube is closed at this end with a pH-sensitive glass membrane. The
end section of the sensor comprising the connection point of the
inner glass tube with the outer glass tube and the glass membrane
is provided to be brought into contact with the measuring liquid,
for example by immersion. This end section of the glass assembly
comprises at least one diaphragm, via which an electrochemical
connection is ensured between a reference electrode, which is
arranged in the chamber formed between the outer glass tube and the
inner glass tube, and a medium surrounding the sensor.
[0004] In the conventional production of glass assemblies, the
material is processed by the following processes, for example:
melting, blowing-in by means of air supply from the inside,
drawing, compression, molding with tools, and the like.
[0005] Solenoid valves or mass flow controllers are used for
blowing in air. Solenoid valves switch a predefined air flow on and
off in a pulse-like manner, the pulse duration being determined via
the magnitude of the introduced air flow. Mass flow controllers
define the introduced volume of air but cannot change the pressure.
Both systems are constructed as open systems, that is, the
component is not connected to the pressure control in an airtight
manner.
[0006] The conventional production of such glass assemblies thus
requires a great deal of manual labor of an experienced glassblower
and is highly complex.
SUMMARY
[0007] The object of the present disclosure is to provide a more
efficient method for the automatic production of generic glass
assemblies, which method enables a higher throughput,
advantageously with a constant or improved quality of the glass
assemblies produced.
[0008] The object is achieved by an apparatus which has an outer
tube and an inner tube running inside the outer tube, wherein the
inner tube and the outer tube are arranged coaxially, and wherein
one end of the inner tube is connected in a firmly bonded manner,
for example, fused, to a tube wall of the outer tube, comprising: a
turning machine with at least two spindles which are rotatable
about a common axis of rotation and which each have a workpiece
holder, wherein the workpiece holders are arranged opposite one
another; one or more gas burners or lasers fixed on a first tool
carriage which is movable in parallel and/or perpendicularly to the
axis of rotation of the spindles; one or more drives for driving a
rotational movement of the spindles and a movement of the first
tool carriage; a pressure module comprising a pump device for
applying a pressure to the inner tube and/or to a space between the
inner tube and the outer tube, wherein the pump device for applying
the pressure comprises at least one working cylinder, for example,
a pneumatic cylinder, a hydraulic cylinder or an electric cylinder;
and a control unit which is designed to control the burners or
lasers, one or more drives of the spindles, the first tool
carriage, and the pressure module.
[0009] One embodiment provides that the pressure module comprises a
pressure sensor, and a regulation of the pressure in the inner tube
and/or in the space between the inner tube and the outer tube takes
place to a target value and controls the pump device
accordingly.
[0010] Thus, a finely metered pressure can be directed into a glass
assembly for its processing. The pressure may be positive or
negative. Any wear in the mechanism is automatically readjusted,
for example, by the pressure sensor feeding back the actual value
of the pressure.
[0011] One embodiment provides that the apparatus furthermore
comprises a camera which is connected to the control unit in order
to communicate digital image data to the control unit. The camera
is installed.
[0012] One embodiment provides that the apparatus furthermore
comprises a second tool carriage which is movable in parallel
and/or perpendicularly to the axis of rotation of the spindles and
on which a camera is arranged, which is connected to the control
unit in order to communicate digital image data to the control
unit.
[0013] One embodiment provides that the working cylinder comprises
a piston rod and a movement back and forth is possible.
[0014] One embodiment provides that at least one workpiece holder
has a seal, for example, a shaft sealing ring.
[0015] One embodiment provides that the working cylinder comprises
a rotary encoder.
[0016] One embodiment provides that the pressure module comprises
an opening valve, by means of which rapid opening and discharging
of the pressure in the inner tube and/or in the space between the
inner tube and the outer tube is made possible.
[0017] One embodiment provides that at least one workpiece holder
is designed to be movable in the direction of the further workpiece
holder.
[0018] One embodiment provides that the apparatus comprises a tool
for processing the outer tube; the tool is, for example, arranged
on a third tool carriage which is movable in parallel and/or
perpendicularly to the axis of rotation of the spindles.
[0019] The object is furthermore achieved by a method for the
automated production of glass assemblies by means of a described
apparatus, wherein the glass assemblies each have an outer tube and
an inner tube running inside the outer tube, wherein the inner tube
and the outer tube are arranged coaxially, and wherein one end of
the inner tube is connected in a firmly bonded manner, for example,
fused, to a tube wall of the outer tube, comprising the steps of:
production of a glass body comprising an outer tube and two inner
tubes arranged inside the outer tube and arranged one behind the
other coaxially to an axis of rotation of the outer tube, wherein
the inner tubes are connected in a firmly bonded manner, for
example, fused, to the outer tube at their end turned toward the
respective other inner tube; and application of a pressure to the
inner tube and/or to a space between the inner tube and the outer
tube, wherein the method is carried out by means of an automatic
control unit.
[0020] One embodiment provides the method step of splitting the
glass body into two separate glass assemblies.
[0021] One embodiment provides the method step of regulating the
pressure in the inner tube and/or in the space between the inner
tube and the outer tube to a target value.
[0022] One embodiment provides the method steps of recording image
data of the glass body; and controlling the production of the glass
body, the application of the pressure, and/or the splitting of the
glass body by means of the recorded image data.
[0023] One embodiment provides the method step of moving at least
one workpiece holder in the direction of the other workpiece holder
for drawing or compressing the glass body.
[0024] One embodiment provides the method step of processing the
outer tube by means of a tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] This is explained in more detail with reference to the
following figures:
[0026] FIG. 1 shows a schematically illustrated glass assembly for
a potentiometric pH sensor;
[0027] FIG. 2 shows a schematic illustration of an apparatus for
the automated production of glass assemblies such as those
illustrated in FIG. 1;
[0028] FIG. 3 shows a schematic illustration of a section of a
glass body for the simultaneous production of two glass assemblies
such as those shown in FIG. 1;
[0029] FIG. 4a shows a schematic illustration of the production of
two through-openings in a wall of an outer tube of the glass body;
and
[0030] FIG. 4b shows a schematic illustration of the splitting of
the glass body into two separate glass assemblies such as those
illustrated in FIG. 1.
DETAILED DESCRIPTION
[0031] FIG. 1 schematically illustrates a glass assembly 1 that can
be processed to produce a potentiometric sensor, for example, a pH
sensor. The glass assembly 1 has an inner tube 6 and an outer tube
3, which are arranged coaxially with respect to their common axis
of rotation Z. A diaphragm 2 is arranged in the tube wall of the
outer tube 3 and connected in a firmly bonded manner to the tube
wall of the outer tube 3 by fusing into the tube wall. The
diaphragm 2 is respectively formed by a cylindrical porous ceramic
body.
[0032] At a connection point 7, the inner tube 6 and the outer tube
3 are fused together. The connection point 7 closes one end of an
annular chamber 8 formed between the inner tube 6 and the outer
tube 3. The inner tube 6 is open at its end 9 located in the area
of the connection point 7.
[0033] The production of a pH sensor with a glass electrode made of
the glass assembly 1 may, for example, be carried out in the
following manner. A pH-sensitive glass membrane that closes the
inner tube 6 at the front side can be blown onto the front, open
end 9 of the glass assembly 1. A buffer solution and a potential
discharger are then introduced into the inner tube 6. A reference
electrolyte and a reference electrode are introduced into the
chamber 8 formed between the inner tube 6 and the outer tube 3. The
glass assembly 1 can then be closed on the rear side, wherein the
reference electrode and the potential discharger are conducted to a
contact point which is arranged outside the chambers that are
formed in the glass assembly 1 and filled with electrolyte. The
contact point may be connected to a measuring circuit, which may be
arranged in an electronic housing that is connected firmly at the
rear side to the glass assembly and that can be designed, for
example, as a plug head.
[0034] A glass membrane may be blown onto the front, open end 9 of
the inner tube 3 in an automated manner. The thickness of the glass
membrane thus automatically produced depends on the opening
diameter d of the open end 9 of the inner tube 3. For series
production of glass assemblies such as those illustrated in FIG. 1
by means of an automatic method, it is thus desirable for the
method to provide for the production of the glass assemblies with
the smallest possible variance of the opening diameters d.
[0035] FIG. 2 schematically shows an apparatus 101 for producing
such glass assemblies. The apparatus 101 comprises a turning
machine with opposing spindles 113, 114 rotatable about a common
axis of rotation Z. An outer tube 103 made of glass is clamped at
its first end in a workpiece holder of the first spindle 113 and at
its second end in a workpiece holder of the second spindle 114. A
first inner tube 106 made of glass is held in the workpiece holder
of the first spindle 113 and a second inner tube 110 made of glass
is held in the workpiece holder of the second spindle, wherein the
first inner tube 106, the second inner tube 110, and the outer tube
103 are coaxially arranged. This is ensured by two centering aids
130, 131, which have a cylindrical body made of stainless steel.
The centering aids 130, 131 have a front-side holder, in which a
section of the respective inner tube 106, 110 is arranged and
fixed. In the present example, the cylinder axis of the centering
aids coincides with the axis of rotation of the inner tubes 106,
110 and the axis of rotation Z of the spindles 113, 114. One end
section of the inner tubes 106, 110 respectively projects from the
holder of the centering aid 130, 131. The glass assembly 102 is
provided with a seal 121 on each side so that a gas-tight seal
results. The seal 121 for clamping the assembly 102 is, for
example, a shaft seal.
[0036] The first and/or the second spindle 113, 114 is mounted in a
movable manner. Thus, the spindles 113, 114 can move with respect
to one another. This is indicated by the reference signs 119 and
120 respectively. Thus, an assembly 102 clamped therebetween can be
compressed or stretched upon corresponding heating by a burner 116,
see below. The camera 142, see below, monitors the process. A
target value for a corresponding geometry of the assembly 102 is
stored in a memory of a control unit 143, see below, so that
automatic regulation results.
[0037] A centering ring 132, 133 is arranged between the outer wall
of the centering aids 130 and 131 and the inner wall of the outer
tube 103 and rests against the inner wall of the outer tube 103 and
the outer wall of the respective centering aid 130, 131. The inner
tubes 106, 110 each have an annular or disk-shaped radial
enlargement 134, 135 on ends turned toward one another.
[0038] A first gas supply line 137 opens into the interior of the
first inner tube 106 and/or into the interior of the outer tube 103
(only schematically indicated in FIG. 2). A second gas supply line
138 opens into the interior of the second inner tube 110 and/or
into the interior of the outer tube 103. Gas can be blown through
the tubes 103, 106, 110 via the gas supply lines 137, 138, and a
desired gas pressure can be set during processing.
[0039] The apparatus 101 comprises a first tool carriage 115 and
one or more gas burners arranged thereon, indicated only
schematically in FIG. 2 as a single gas burner 116, which can be
moved relative to the axis of rotation Z or to the glass tubes
clamped in the spindles 113, 114 by means of the tool carriage 115
and/or a burner support optionally arranged on the tool carriage
115. Instead of the gas burners, other heat sources, for example
lasers, may alternatively also be used. It is also possible to
combine gas burners and lasers, for example in such a manner that
individual method steps are carried out with laser processing,
others with gas flames. The method described below as an example
utilizes only gas flames.
[0040] The apparatus 101 furthermore comprises a further tool
carriage 154 (a third tool carriage within the meaning of this
application) on which a gray cast shaping roller 141 is arranged
and which is rotatably mounted about an axis running in parallel to
the axis of rotation Z. The shaping roller 141 is movable
perpendicularly to the axis of rotation Z by means of the tool
carriage 154 and can be brought into contact with the outer tube
103 in order to process the outer tube 103.
[0041] In addition, the apparatus 101 comprises a camera 142 that
is aligned with respect to the tube arrangement formed from the
tubes 103, 106, and 110, in such a manner that it is able to record
images of a central area of the tube arrangement, hereinafter
referred to as the processing center 109. In the exemplary
embodiment shown here, the camera 142 is a digital camera. The
camera is mounted on a second tool carriage 140 in a movable
manner. The camera may also be installed in a stationary
manner.
[0042] The apparatus 101 comprises a pressure module. Reference
sign 148 designates a pump device for applying a pressure to an
inner tube 106, 110 and/or to a space between the inner tube 106,
110 and the outer tube 103. The pump device 148 is controlled via a
data transmission device 151 by a control unit 143, see below.
Furthermore, a pressure measuring device 149 in the form of a
pressure sensor is arranged, which detects the pressure in the
inner tube 106, 110 and/or at the space between the inner tube 106,
110 and the outer tube 103 and transmits it via a transmission
device 150 to the control unit 143. In this manner, a control loop
is formed in order to control to a target value stored in a memory
of the control unit 143. The target value may also be designed as a
time-variable function.
[0043] The pump device 148 for applying the pressure comprises at
least one working cylinder, for example, a pneumatic cylinder, a
hydraulic cylinder or an electric cylinder. The working cylinder
comprises a piston rod and makes movement back and forth possible.
Pressure thus cannot only be introduced but can also be discharged
again without the glass body 102 having to be detached from the
seal 121. It is thus possible to introduce extended geometries into
the glass. The working cylinder comprises a rotary encoder so that
precise metering of the pressure is possible. The pressure module
comprises an opening valve 152, by means of which rapid opening and
discharging of the pressure in the inner tube 106, 110 and/or in
the space between the inner tube 16, 110 and the outer tube 103 is
made possible.
[0044] The apparatus 101 furthermore comprises a control unit 143,
which controls the drives of the spindles 113, 114, the drives of
the tool carriages 115, 140, the applied pressure with which gas is
blown into the tube arrangement via the gas supply lines 137 and/or
138 and controls the gas burner(s) 116, for carrying out the method
described here according to a predetermined operating program. For
controlling and/or regulating the blowing pressure, the control
device can use measured values of one or more pressure sensors,
which detect the gas pressure in the gas supply lines.
[0045] In order to control and/or regulate the gas burners, the
control unit uses measured values of one or more pyrometers, which
measure the temperature of the areas of the tube arrangement heated
by means of the gas burners 116. All steps described here and below
are carried out in an automated manner in the present example by
means of the control unit 143.
[0046] The control unit 143 may include an electronic data
processing device, such as a conventional PC, or a different
programmable control unit. It is connected to the camera 142 in
order to control the same for recording image data of the
processing center 109 and/or to receive and further process image
data recorded by the camera 142.
[0047] For the production of glass assemblies such as those
illustrated in FIG. 1, the apparatus 101 is operated in the
following manner by means of the control unit 143.
[0048] In a first step, a glass body is produced by fusing the
inner tubes 106, 110 by melting the two inner tubes 106, 110 at
their end turned toward the respective other inner tube with the
outer tube 103. For this purpose, the tube arrangement is heated at
the processing center 109 by means of a gas burner 116 arranged on
the carriage 115. The processing temperature at the processing
center 109 is controlled by means of the control unit 143, as
previously indicated. In this case, the spindles 113, 114 rotate
about the axis Z so that a uniform heating is ensured over the
entire circumference of the tube arrangement at the processing
center 109. Due to the heating, optionally assisted by an expansion
of the distance of the spindles 113, 114 in the direction of the
axis of rotation Z, the diameter of the outer tube 103 in the
heated area is narrowed to such an extent that the outer tube 103
comes into contact with the enlarged areas 134, 135 of the inner
tubes and is fused with them. In the process, the camera 142
records image data of the tube arrangement in the area of the
processing center 109.
[0049] FIG. 3 schematically illustrates the processing center 109
of the tube arrangement shown in FIG. 2 during the fusion of the
outer tube 103 with the inner tubes 106, 110. After the subsequent
separation of the glass body into two individual glass assemblies
corresponding to the glass assembly shown in FIG. 1, the outer
diameter of the outer tube 103 in the area of the connection points
determines the opening diameter d (cf. FIG. 1) of the open end at
which the separation has taken place. By means of the image data
recorded by the camera 142, the outer diameters are recorded and
monitored by the control unit 143 during the fusion. In a memory of
the control unit 143, a target value of the outer diameter is
stored as a limit diameter. Upon reaching the predetermined limit
diameter, the control unit 143 terminates the fusion process and
continues the method with the next method step. As a result of the
production, the outer diameters of the end-side enlargements of
different inner tubes in series production according to the method
described here have a certain variance so that the setting of a
desired outer diameter requires a different length of processing
time during fusing, depending on the diameter of the enlargement.
The tolerance field of the opening diameters d of the glass
assemblies produced in series production can be reduced by
controlling the outer diameters at the fusion points.
[0050] A single glass body is formed from the tube arrangement
shown in FIG. 2 by fusing the inner tubes 106, 110 with the outer
tube 103. This glass body is then processed in the processing
center or heated by means of the gas burner 116 using the shaping
roller 141.
[0051] The resulting glass body 102 is shown in FIG. 4a. The outer
tube 103 is now connected to the first inner tube 106 at the
connection point 107 and to the second inner tube 110 at the
connection point 111. As a result, a first annular chamber 108 is
formed between the first inner tube 106 and the outer tube 103, and
a second annular chamber 112 is formed between the second inner
tube 110 and the outer tube 103.
[0052] In order to produce openings for a diaphragm in the wall of
the outer tube 103, two gas burners 117, 118 arranged on the tool
carriage 115 are each approximated to a position with a
predetermined distance from the processing center on the outer side
of the outer tube 103. By means of the gas burners 117, 118, the
outer tube 103 is locally heated at these positions. At the same
time, by introducing gas, for example air, into the annular
chambers 108, 112 via the gas supply lines 137, 138, the pressure
inside the annular chambers 108, 112 is increased so that openings
105 are formed in the tube wall when the tube wall softens in the
heated area. The gas can enter the otherwise closed annular
chambers 108, 112 via channels 144, 145 arranged in the centering
aids 130, 131. Porous ceramic diaphragms 146, 147 (cf. FIG. 4b) are
inserted into the openings 105 in one step and are melted by means
of the gas burners 117, 118.
[0053] In a final step (FIG. 4b), using a gas-oxygen flame of one
of the gas burners 116, the glass body is split at the processing
center 109 into two separate glass assemblies, both corresponding
to the glass assembly illustrated in FIG. 1, while at the same time
gas, for example air, is blown in via the gas supply lines 137, 138
through the inner tubes 106, 110 in the direction of the processing
center. For this purpose, the control unit 143 controls both the
gas flame and the blowing pressure in such a manner that, when the
glass body 102 is split into two separate glass assemblies, the
ends 9 turned toward one another of the two glass assemblies (FIG.
1) resulting from the separation remain open. The blowing pressure
data and associated exposure times of the heat source and of the
blowing pressure are stored in the operating program of the control
unit 143.
[0054] In a final step, the ends turned toward one another of the
glass assemblies resulting from the separation are thermally
expanded by a heat treatment by means of a gas burner 116.
* * * * *