Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/04—Re-forming tubes or rods
  • C03B23/047—Re-forming tubes or rods by drawing
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
  • C03B37/01—Manufacture of glass fibres or filaments
  • C03B37/012—Manufacture of preforms for drawing fibres or filaments
  • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
  • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
  • C03B37/0124—Means for reducing the diameter of rods or tubes by drawing, e.g. for preform draw-down

Definitions

• the present invention relates to a vertical drawing process for the production of a cylindrical glass body, in particular a quartz glass body, comprising a drawing phase and a drawing phase, wherein during the drawing phase a glass cylinder is fed along a drawing axis with its lower end, starting from a heating zone, then softens, from the softened area with formation a pulling onion produces a pulling strand, this is fed to a trigger and is pulled off during the pulling phase to form a glass strand with a predetermined nominal dimension, and the glass strand is then cut to the cylindrical glass body
• the invention relates to a device for performing the method.
• Such methods and devices are used to manufacture cylindrical components, in particular tubes and rods made of quartz glass with any cross-sectional profile, or of preforms for optical fibers.
• DE 101 17 153 A describes such a vertical drawing process for producing a full cylinder made of quartz glass by pulling it from a
• the known vertical drawing process comprises a drawing phase and the actual drawing phase.
• the tightening phase is initiated by feeding a glass cylinder in the form of a tube or rod in a vertical orientation from above to a heating source, then softening it, and then dropping a glass item from the softened area of the glass cylinder as a result of gravity, feeding it to a tractor and thus initially a pulling string
• the pulling string is initially small in diameter, so that a higher speed of the tractor rollers is required during the tightening phase.
• the tractor speed is gradually reduced The rate at There are limits to how fast the take-off speed can be.
• Pull-off strand is removed as explained and the outer diameter is built up.
• the glass strand is pulled down from the glass cylinder at a controlled drawing speed during the actual drawing phase in such a way that the nominal diameter or nominal wall thickness is maintained.
• Z-shaped glass bodies are produced from the glass strand by cutting suitable sections to length.
• the glass mass drawn off during the tightening phase is discarded.
• the tightening phase therefore represents an essential material and time factor of the vertical pulling process.
• a shortening of the distance between the trigger and the onion is often not possible, because on the one hand high temperatures prevail just below the pulling onion and on the other hand the axial guidance of the glass strand when the trigger is arranged above deteriorates and the cutting of the sections is difficult.
• the invention is therefore based on the object of specifying a vertical pulling method with a shortened pulling-on phase and of providing a device which is suitable for carrying out the method.
• this object is achieved, based on the method mentioned at the outset, in that the pulling strand is produced using an axially movable tightening device arranged in the pulling axis, which is connected on the one hand to the lower end of the glass cylinder, and on the other hand by means of the trigger can be pulled down at a predetermined pull-off speed.
• the tightening is initiated by means of an axially movable tightening device which extends between the lower end of the glass cylinder and the trigger.
• the pulling device can be moved downward in the pulling axis by means of the trigger, but itself is designed to be rigid (axially rigid).
• the forces and movements transmitted from the trigger to the pulling device have a direct effect on the softened area of the glass cylinder and the gradually growing onion there. In this respect, the distance between the trigger and the onion is shortened by using the tightening device.
• the use of the tightening device has an advantageous effect:
• the tightening device replaces at least that part of the tightening strand that would otherwise have been necessary to bridge the distance between the glass cylinder and the trigger.
• the pulling strand that forms is therefore not between the glass cylinder (or
• the pulling device can be used to support the glass item falling down and the pulling string that forms from below, thereby accelerating the diameter build-up of the pulling string.
• the tightening device can be used to strongly press against it from below without the tightening strand becoming deflected or kinked.
• the nominal dimension of the glass strand becomes very fast through a strong counterpressure - shortly after
• Another advantage of the method according to the invention is that the tightening device can be precisely aligned before the start of the drawing process, also with the aid of suitable adjustment means, so that an exactly centric - in relation to the glass cylinder to be drawn and the heating device - and vertical orientation as well as a Pulling off in the pull axis can be ensured.
• the tightening device preferably has a support part and an elongate pull-off part connected to it, the support part fusing with the pull-in strand and the pull-off part being gripped and pulled off in the pulling axis by means of the pull-off.
• the tightening device is connected to the trigger on the one hand by clamping the elongated trigger part of the tightening device in the trigger and pulling it downwards by means of the trigger.
• the tightening device is also fused via the support part to the glass cylinder or to the pulling strand formed therefrom. This fusing can take place before the drawing process or during the drawing process, in that the support part supports the glass plug which sinks down due to the force of gravity and thereby connects to it. Since also the trigger part and support part are firmly connected to each other, the movements and forces of the trigger are transferred directly to the pulling string that is formed.
• the glass item which is lowered as a result of gravity can be supported on the supporting part, so that - in particular because of the shortness of the pulling string and the associated low risk of
• a tightening strand can be formed by means of the tightening device, which has dimensions in the area of the nominal dimension at an early stage.
• connection between the support part and the pull-in strand is created only during the pulling process, and automatically, without additional production outlay, as soon as the support part is pressed against the pull-down strand falling downward.
• the method also allows a comparatively low overall height of the drawing system.
• the support part preferably consists of quartz glass. This results in a simple connection possibility between the support part and the pulling string by fusing.
• a tightening device in which the trigger part and the support part are formed in one piece.
• the extraction device consists of a quartz glass rod or a quartz glass tube, the upper end face of the tube or rod serving as a supporting part in the sense of the present invention and the elongated part of the tube or rod serving as a trigger part which detects by means of the trigger and is subtracted.
• the trigger part and the support part are detachably connected to one another.
• the pull-off part it is possible to use the pull-off part several times by detaching it from the support part connected to the glass body after use.
• a preferred procedure consists in connecting the trigger part and the support part to one another by means of an adapter piece.
• the adapter piece By means of the adapter piece, it is possible to adapt one end to the connection with the pull-off part and to design the other end of the adapter piece for the connection to the support part, in particular also to support parts with different radial dimensions adapted to the cross-sectional area of the pulling strand to be supported.
• the support part and trigger part are preferably held in a form-fitting manner in the adapter piece; with small dimensions, a frictional connection is sufficient.
• the pull-off speed is at least temporarily set to a value in the range of a nominal pull-off speed required to achieve the nominal dimension.
• the method according to the invention makes it possible to operate the trigger very early, ideally immediately after the tightening strand has been built up, that is to say in any case during most of the time in the tightening phase, at the nominal trigger speed.
• This is understood to mean the take-off speed that would lead to a glass strand with the nominal dimensions given the given glass cylinder dimensions and at a constant feed speed.
• the pulling process is therefore already carried out at the nominal take-off speed when the connection point between the pulling device and the pulling strand passes the pull. This results in favorable control behavior, which further reduces material loss.
• the tightening phase ends as soon as the tightening strand has reached the nominal diameter. This is usually the case before the connection point between the tightening device and the tightening strand has passed the trigger.
• the conical extension facilitates the passage of this area through the trigger.
• the trigger usually consists of one or more pairs of rollers lying opposite one another on the glass strand, which bear against the outer surface of the glass strand and roll on it with a predetermined rotational speed and torque.
• the support part here has a support surface which is adapted to the cross-sectional area of the pull-in strand.
• the support surface is ideally dimensioned such that it has just a sufficiently large area to support a tightening strand with a nominal dimension.
• a support surface that is significantly larger than required causes unnecessary problems when passing the trigger by interfering with the regulation when the connection point between the support part and the pulling string passes through the trigger.
• the conical extension facilitates the passage of the connection point between the support part and the pulling string through the trigger. This measure is not necessary if an appropriately designed adapter piece between Deduction part and support part is provided, which extends conically upwards to about (+/- 50%) on the cross section of the pull-in cord.
• a further improvement of the method results if the withdrawal part has a constant radial cross section over a substantial part of its length - seen perpendicular to the drawing axis - which is not larger than the radial cross section of the support surface.
• the trigger part is made as thin as possible, but as thick as necessary to ensure the required mechanical stability, in particular the bending stiffness.
• the trigger part has cylindrical symmetry with a uniform length
• Diameter or with uniform radial dimensions It can be formed in one part or in several parts, preferably it is composed of a plurality of elongate segments which can be axially connected to one another and thus its length can be changed. It can also be designed telescopically, in which case a suitable locking device must be provided, the one
• the method according to the invention is particularly advantageous when the distance between the onion and the trigger is large. This distance is bridged by the trigger part.
• the above-mentioned essential part of the length of the trigger part therefore has a length of at least 1 m, preferably a length of at least 2 m.
• the trigger part comprises a linkage made of light metal.
• Light metal is characterized by low weight with high mechanical strength and stability.
• the support surface of the support part can “overflow” come. This risk is reduced if the glass cylinder is initially provided with a tapered or drop-shaped end, which also saves time since less material has to be heated and the tightening process is thus accelerated.
• a device which comprises a trigger and an axially movable tightening device which is arranged in the drawing axis and extends between the lower end of the glass cylinder and the trigger and which has a supporting part for Having a pulling strand sinking from the lower end of the glass cylinder and an elongated trigger part connected thereto, the supporting part being connected to the pulling strand and the pulling part running in the pulling axis being detectable by means of the trigger.
• the tightening is initiated by means of an axially movable tightening device which extends between the lower end of the glass cylinder and the trigger.
• the tightening device can be moved downward in the drawing axis by means of the trigger, but itself is designed to be rigid (axially rigid).
• the movements of the tightening device caused by the trigger are transferred directly to the softened area of the glass cylinder and to the onion which gradually forms there. In this respect, the distance between the trigger and the onion is shortened by using the tightening device.
• the tightening device has a support part and an elongated pull-off part connected to it, the support part fusing with the pulling strand and the pulling part being gripped and pulled off in the pulling axis by means of the pull-off.
• the tightening device is connected to the trigger on the one hand by clamping the elongated trigger part of the tightening device in the trigger and pulling it downwards by means of the trigger.
• the tightening device is also with the glass cylinder or with the support part the resulting pulling strand fused. This fusing can take place before the drawing process or during the drawing process, in that the support part supports the glass plug which sinks down due to the force of gravity and thereby connects to it. Since the trigger part and the support part are also firmly connected to one another, the movements of the trigger have a direct effect on the pulling strand that is formed.
• the glass item which sinks down due to the force of gravity, can be supported on the supporting part, so that a comparatively faster build-up of a tightening strand with a nominal dimension is made possible.
• a tightening strand can be formed by means of the tightening device, which has dimensions in the area of the nominal dimension at an early stage.
• Figure 1 shows an embodiment of the device according to the invention and an embodiment of the drawing method according to the invention for producing a quartz glass tube in a schematic representation.
• Figure 1 shows an embodiment of the device according to the invention and a state of the vertical pulling method during the tightening phase.
• a quartz glass hollow cylinder 1 with an initially slightly conical lower end becomes a heater from above along the directional arrow 2 3 fed.
• the heating device 3 the lower, conical end softens and begins to sink under the influence of gravity and the formation of a drawing onion.
• the sinking glass item is supported directly by means of a tightening device, to which reference number 4 is assigned.
• the tightening device 4 comprises a trigger rod 5 composed of individual segments, an adapter piece 6 and a support 7 in the form of a tube piece made of quartz glass.
• the support 7 protrudes from above into a receptacle of the adapter piece 6 and is fixed therein by means of countersunk screws 8.
• the adapter piece 6 has a conically tapering area 9 which opens into a pin 10.
• the pin 10 is screwed to the trigger rod 5 by means of a threaded connection 11.
• the trigger rod 5, which is also made of aluminum, has a length of 3.5 m and an outer diameter of 35 mm.
• the lower end 12 of the trigger rod 5 is guided by the pair of rollers of a so-called tractor 13, by means of which the trigger rod 5 can be pulled down between the counter-rotating rollers (arrow 2).
• the quartz glass hollow cylinder 1 with an outer diameter of 180 mm and a wall thickness of 60 mm and the tightening device 4 are first exactly aligned in the drawing axis 15. Subsequently, the lower end of the quartz glass hollow cylinder 1 is fed from the top of the heating device 3 at a feed rate of 50 kg / h and heated to a temperature of approximately 2200 ° C. therein. The lower end of the quartz glass hollow cylinder 1 with an outer diameter of 180 mm and a wall thickness of 60 mm and the tightening device 4 are first exactly aligned in the drawing axis 15. Subsequently, the lower end of the quartz glass hollow cylinder 1 is fed from the top of the heating device 3 at a feed rate of 50 kg / h and heated to a temperature of approximately 2200 ° C. therein. The lower end of the
• Quartz glass cylinder 1 As soon as the quartz glass has softened enough to begin to sink down under the influence of gravity, it is supported by means of the support 7 by pressing the upper side 17 against the softened area. As a result, the glass item on the support 7 increases gradually and is formed into a pull-in tube 14 by slowly lowering the support 7. The lowering speed is chosen so that the outer diameter of the pull tube 14 gradually increases until it approximates that of the tubular support 7. This outer diameter also corresponds to the nominal diameter of the pipe string to be drawn in the actual drawing phase. As a result of this sinking and supporting process, there is at the same time a firm fused connection between the upper side 17 of the support 7 and the tightening tube 14. The surface of the upper side 17 of the support 7 is therefore dimensioned exactly such that it corresponds to the cross-sectional area of the pipe string to be drawn with nominal Dimension corresponds.
• the pulling device 4 is pulled down by means of the tractor 13, initially slowly, but soon with a nominal pull-off speed of 66.7 mm / min. This take-off speed leads to the stated feed rate and the dimensions of the quartz glass hollow cylinder 1 (without
• the area of the connection between the tightening pipe 14 and the pipe section 7 can often be seen from a circumferential bead 16.
• the usable part of the pipe string to be drawn off begins immediately above the bead 16, so that the pulling speed can be set in accordance with the nominal pulling-off speed during the pulling phase.
• the bead 16 and the unusable part of the pull tube 14 pass the tractor 13, the conical region 9 of the adapter piece 6 facilitating the passage through the rollers of the tractor 13.
• the firm fusion connection between the pipe section 7 and the tightening pipe 14 prevents the tightening device 4 from loosening and falling down.
• the pipe string is drawn with the dimensions mentioned above and cut to the desired partial lengths.
• the use of the trigger device 4 enables the tightening phase to be shortened.
• the pull-in tube 14 is built up very quickly with the external dimensions which come close to the nominal dimensions of the tube string to be drawn off.
• the tightening device 4 By means of the tightening device 4, the softened glass item and the tightening tube 14 that is being built up are supported from below, whereby the diameter build-up in the tightening tube 14 is accelerated.
• the pull tube 14 is only comparatively short in length and can therefore be pressed against it with a large force from below without the pull tube 14 bending or bending.
• the tightening device 4 replaces that part of a rigid tightening strand that would otherwise have been necessary to bridge the distance between the hollow cylinder 1 and the tractor 13.
• the nominal outer diameter is already reached after a period of about 3 minutes.
• the drawing tube 14 which forms the total quartz glass mass to be rejected usually has a length of less than 250 mm.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Manufacturing & Machinery (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
• Manufacture, Treatment Of Glass Fibers (AREA)

Priority Applications (2)

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Citations (4)

• 2002
  • 2002-09-02 DE DE2002140950 patent/DE10240950B3/de not_active Expired - Fee Related
• 2003
  • 2003-09-02 WO PCT/EP2003/009739 patent/WO2004024643A1/de active Application Filing
  • 2003-09-02 AU AU2003270140A patent/AU2003270140A1/en not_active Abandoned
  • 2003-09-02 JP JP2004535225A patent/JP2005537214A/ja active Pending

Patent Citations (4)

Non-Patent Citations (3)

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