EP0097669A1 - A device in equipment for drawing glass fibres - Google Patents

A device in equipment for drawing glass fibres

Info

Publication number
EP0097669A1
EP0097669A1 EP83900082A EP83900082A EP0097669A1 EP 0097669 A1 EP0097669 A1 EP 0097669A1 EP 83900082 A EP83900082 A EP 83900082A EP 83900082 A EP83900082 A EP 83900082A EP 0097669 A1 EP0097669 A1 EP 0097669A1
Authority
EP
European Patent Office
Prior art keywords
fibre
fiber
chamber
cooling
equipment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83900082A
Other languages
German (de)
French (fr)
Inventor
Lubos Josef Bohuslav Vacha
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of EP0097669A1 publication Critical patent/EP0097669A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
    • C03C25/10—Coating
    • C03C25/12—General methods of coating; Devices therefor
    • C03C25/16—Dipping
    • 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
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/022—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from molten glass in which the resultant product consists of different sorts of glass or is characterised by shape, e.g. hollow fibres, undulated fibres, fibres presenting a rough surface
    • C03B37/023—Fibres composed of different sorts of glass, e.g. glass optical fibres, made by the double crucible technique
    • C03B37/0235—Thermal treatment of the fibre during the drawing process, e.g. cooling
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
    • C03C25/10—Coating
    • C03C25/104—Coating to obtain optical fibres
    • C03C25/106—Single coatings

Definitions

  • the invention relates to a device in equipment for drawing optical fibres.
  • Optical fibres are produced by continuous drawing from a melt in a double crucible or from a so-called preform which is heated to a semi-liquid condition- As soon as possible after drawing, the fibre is provided with a coating to increase its strength so that it can be handled without risk for rupture when winding onto a reel and during later cable manufacture.
  • the coating is usually carried out by the drawn glass fibre passing as soon as possible through a bath of coating material, usually heat-curable silicon rubber. This coating method functions well for thinner fibre dimensions.
  • a device in equipment for drawing glass fibres in accordance with the invention includes a cooling means placed after the drawing location, and its character ⁇ izing features are apparent from the appended claims.
  • the numeral 10 denotes a melting crucible for glass, in this case a so-called double crucible of the kind described in the article "Optical Fibres" in the Ericsson Review No 3, 1980, pages 12 and 13. It is primarily intended for producing optical fibres of the so-called step-index type, but can also be used in the production of graded index fibres. It includes an inner crucible 11 containing a glass melt 13 with a high refractive index intended to form the core in the glass fibre, and an outer crucible 12 with a glass melt 14 having a low refractive index and intended to form the sheath or casing of the fibre.
  • the glass melt 13 from the inner crucible runs slowly out through the nozzle 15 in the inner crucible 11, passing through the outer crucible and out through the outer nozzle 16. When it passes the latter nozzle, the core is surrounded by glass from the outer crucible. When the glass melt has passed the outer nozzle 16 a meniscus 17 is formed, and from this the glass is drawn out into a thin fibre 18 with the aid of a capstan means 26.
  • the drawn fibre will have a core of the glass 13 and a cladding of the glass 14.
  • the fibre diameter is dependent on the drawing rate of the capstan means and the outflow rate through the nozzles 15 and 16, the rate in turn depending on the temperature and viscosity of the glass melts.
  • the diameter is measured with a thickness meter 19 which controls the drawing rate of the capstan means with the aid of suitable conventional control equipment.
  • the fibre After drawing, the fibre is sensitive to scratches and contamination, and must therefore be provided as quickly as possible with a protective coating.
  • OM?I takes place in a receptacle 20 containing suitable liquid coating material, e g curable silicon rubber, which is cured in a suitable, unillustrated heating means after it has adhered to the fibre and when the fibre has passed out from the receptacle 20.
  • suitable liquid coating material e g curable silicon rubber
  • a cooling chamber 21, through which the drawn fibre passes is arranged between the drawing nozzle 16 and the receptacle.
  • the cooling chamber 21 comprises a tube 22 of a porous material with very fine open pores.
  • the material may suitably be a porous metal, e g bronze, produced by sintering or some other method.
  • the material can also be of other types, e g microporous ceramics or plastics.
  • a vessel 23 is arranged round the outside of the tube and provided with a supply pipe 24 connected to a source for compressed gas, preferably dry nitrogen gas. The gas passes through the porous tube 22 and into the space 25 around the fibre.
  • the large number of pores in the tube 22 ensures that the gas flow coming into the space 24 is very uniformly distributed round the fibre and the latter, will not be subjected to any transverse forces.
  • the upper opening of the tube 22 is provided with a shield, e g an iris-type aperture, which is solely provided with a fine hole through which the fibre can pass into the tube 22. Due to the cooling, the distance between the drawing nozzle 16 and the receptacle 20 may be shortened considerably.
  • a dried gas suitably nitrogen gas
  • the risk is further decreased of the fibre absorbing water, which heavily reduces the fibre strength by making its way into the microcracks.
  • the fibre passes then through the bath it is cooled such that no curing takes place therein, and the coating will be uniformly distributed around the filament.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Surface Treatment Of Glass Fibres Or Filaments (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

Abstract

Lors de l'étirage de fibres de verre destinées à la transmission optique, la fibre (18) passe au travers d'une chambre tubulaire de refroidissement (21) après l'étirage, la paroi intérieure (22) de la chambre comprenant un matériau poreux à pores ouverts. La chambre (21) est reliée à une source de gaz comprimé, notamment du gaz d'azote sec. En refroidissant la fibre chaude, on empêche sa contamination et son endommagement par l'humidité de l'air, et la résistance à la traction de la fibre est augmentée par les efforts de compression créés dans la couche extérieure de la fibre. On empêche en outre la fibre de devenir suffisamment chaude pour faire polymériser trop tôt et irrégulièrement le revêtement protecteur en plastique polymérisable, qui est appliqué le plus tôt possible après l'étirage, pour protéger et renforcer la fibre de verre.When drawing glass fibers intended for optical transmission, the fiber (18) passes through a tubular cooling chamber (21) after drawing, the interior wall (22) of the chamber comprising a material porous with open pores. The chamber (21) is connected to a source of compressed gas, in particular dry nitrogen gas. By cooling the hot fiber, it is prevented from being contaminated and damaged by air humidity, and the tensile strength of the fiber is increased by the compressive forces created in the outer layer of the fiber. The fiber is further prevented from becoming hot enough to cure the protective plastic polymerizable coating too soon and irregularly, which is applied as soon as possible after drawing, to protect and strengthen the fiberglass.

Description

A DEVICE IN EQUIPMENT FOR DRAWING GLASS FIBRES
TECHNICAL FIELD
The invention relates to a device in equipment for drawing optical fibres.
BACKGROUND ART
Optical fibres are produced by continuous drawing from a melt in a double crucible or from a so-called preform which is heated to a semi-liquid condition- As soon as possible after drawing, the fibre is provided with a coating to increase its strength so that it can be handled without risk for rupture when winding onto a reel and during later cable manufacture.
The coating is usually carried out by the drawn glass fibre passing as soon as possible through a bath of coating material, usually heat-curable silicon rubber. This coating method functions well for thinner fibre dimensions.
DISCLOSURE OF INVENTION
For heavier fibre dimensions, e g 200-300 um, it has been found that the coating becomes uneven if entry into the silicon rubber bath takes place too close to the drawing location. On entry into the bath it has been found that the fibre has such a high temperature that the rubber cures immediately. One is therefore compelled to move the bath further away from the drawing location, with increased risk of microcracks in the fibre and contamination of its surface, above all with dust and moisture. This increased distance results in a lowering of the drawing speed for thick fibres, due to the fibre diameter decreasing because of the weight thereof. Forced cooling of the fibre close to the drawing location has been found difficult to arrange, since lateral forces which can cause rupture easily occur on the fibre.
In accordance with the invention it is possible to increase the cooling heavily, so that the distance between the drawing location and coating bath may be kept short, simultaneously as the fibre can run without being disturbed by the cooling medium. A device in equipment for drawing glass fibres in accordance with the invention includes a cooling means placed after the drawing location, and its character¬ izing features are apparent from the appended claims.
BRIEF DESCRIPTION OF DRAWING
The invention will now be described in detail in conjunction with the appended drawing where Figure 1 schematically illustrates equipment for drawing and coating optical fibres.
MODE FOR CARRYING OUT THE INVENTION
In Figure 1 the numeral 10 denotes a melting crucible for glass, in this case a so-called double crucible of the kind described in the article "Optical Fibres" in the Ericsson Review No 3, 1980, pages 12 and 13. It is primarily intended for producing optical fibres of the so-called step-index type, but can also be used in the production of graded index fibres. It includes an inner crucible 11 containing a glass melt 13 with a high refractive index intended to form the core in the glass fibre, and an outer crucible 12 with a glass melt 14 having a low refractive index and intended to form the sheath or casing of the fibre. The glass melt 13 from the inner crucible runs slowly out through the nozzle 15 in the inner crucible 11, passing through the outer crucible and out through the outer nozzle 16. When it passes the latter nozzle, the core is surrounded by glass from the outer crucible. When the glass melt has passed the outer nozzle 16 a meniscus 17 is formed, and from this the glass is drawn out into a thin fibre 18 with the aid of a capstan means 26. The drawn fibre will have a core of the glass 13 and a cladding of the glass 14.
The fibre diameter is dependent on the drawing rate of the capstan means and the outflow rate through the nozzles 15 and 16, the rate in turn depending on the temperature and viscosity of the glass melts. The diameter is measured with a thickness meter 19 which controls the drawing rate of the capstan means with the aid of suitable conventional control equipment.
After drawing, the fibre is sensitive to scratches and contamination, and must therefore be provided as quickly as possible with a protective coating. This
OM?I takes place in a receptacle 20 containing suitable liquid coating material, e g curable silicon rubber, which is cured in a suitable, unillustrated heating means after it has adhered to the fibre and when the fibre has passed out from the receptacle 20. A cooling chamber 21, through which the drawn fibre passes is arranged between the drawing nozzle 16 and the receptacle.
The cooling chamber 21 comprises a tube 22 of a porous material with very fine open pores. The material may suitably be a porous metal, e g bronze, produced by sintering or some other method. The material can also be of other types, e g microporous ceramics or plastics. A vessel 23 is arranged round the outside of the tube and provided with a supply pipe 24 connected to a source for compressed gas, preferably dry nitrogen gas. The gas passes through the porous tube 22 and into the space 25 around the fibre. The large number of pores in the tube 22 ensures that the gas flow coming into the space 24 is very uniformly distributed round the fibre and the latter, will not be subjected to any transverse forces. To prevent the gas flow from going upwards and cooling the fibre too early, before it is ready-drawn to the right dimension, the upper opening of the tube 22 is provided with a shield, e g an iris-type aperture, which is solely provided with a fine hole through which the fibre can pass into the tube 22. Due to the cooling, the distance between the drawing nozzle 16 and the receptacle 20 may be shortened considerably. When cooling is carried out with the aid of a dried gas, suitably nitrogen gas,, the risk is further decreased of the fibre absorbing water, which heavily reduces the fibre strength by making its way into the microcracks. By such rapid cooling of the fibre, compression stresses are built into the fibre outer layer so that the tensile strength of the fibre increases in the same way as for hardened glass.
When the fibre passes then through the bath it is cooled such that no curing takes place therein, and the coating will be uniformly distributed around the filament.

Claims

C L A I M S
1 A device in equipment for drawing glass fibres for cooling the fibre after drawing, characterized by a cooling chamber (21) surrounding the fibre (18) and including a tubular container, the inner wall (22) of which comprises a porous material with open pores, the chamber being connected to a source (24) of compressed gas which is caused to pass through the inner wall (22) and out towards the passing fibre (18) in an evenly distributed flow.
2 Device as claimed in claim 1, characterized in that the porous material comprises sintered metal.
3 Device as claimed in claim 1, characterized in that the compressed gas is dry nitrogen gas.
OMPI
EP83900082A 1981-12-29 1982-12-20 A device in equipment for drawing glass fibres Withdrawn EP0097669A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8107823A SE433605B (en) 1981-12-29 1981-12-29 DEVICE FOR A GLASS FIBER TREATMENT EQUIPMENT FOR FIBER COOLING
SE8107823 1981-12-29

Publications (1)

Publication Number Publication Date
EP0097669A1 true EP0097669A1 (en) 1984-01-11

Family

ID=20345387

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83900082A Withdrawn EP0097669A1 (en) 1981-12-29 1982-12-20 A device in equipment for drawing glass fibres

Country Status (5)

Country Link
EP (1) EP0097669A1 (en)
JP (1) JPS58502200A (en)
IT (1) IT1153893B (en)
SE (1) SE433605B (en)
WO (1) WO1983002268A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4913715A (en) * 1984-09-13 1990-04-03 U.S. Philips Corp. Method of manufacturing an optical fiber having a protective coating

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI78893C (en) * 1987-09-08 1989-10-10 Nokia Oy Ab Method and apparatus for cooling an optical fiber.
US4838918A (en) * 1987-12-01 1989-06-13 Alcatel Na Inert atmosphere cooler for optical fibers
US5377491A (en) * 1992-12-11 1995-01-03 Praxair Technology, Inc. Coolant recovery process
US6668582B2 (en) 2001-04-20 2003-12-30 American Air Liquide Apparatus and methods for low pressure cryogenic cooling
US6651358B2 (en) 2001-04-30 2003-11-25 American Air Liquide, Inc. Heat transfer fluids and methods of making and using same comprising hydrogen, helium and combinations thereof
US6574972B2 (en) 2001-04-30 2003-06-10 L'air Liquide - Societe' Anonyme A' Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Low temperature heat transfer methods
US20030205066A1 (en) * 2002-03-25 2003-11-06 Ghani M. Usman Method and apparatus for efficient cooling of optical fiber during its manufacture

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE698179C (en) * 1938-12-30 1940-11-04 Lambert Jansen ze plastic masses, such as B. Glass
DE2734152A1 (en) * 1977-07-28 1979-02-08 Siemens Ag DEVICE FOR DRAWING A BUNCH OF CORE-CLOTHING FIBERS

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8302268A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4913715A (en) * 1984-09-13 1990-04-03 U.S. Philips Corp. Method of manufacturing an optical fiber having a protective coating

Also Published As

Publication number Publication date
IT1153893B (en) 1987-01-21
SE433605B (en) 1984-06-04
JPS58502200A (en) 1983-12-22
WO1983002268A1 (en) 1983-07-07
SE8107823L (en) 1983-06-30
IT8224974A0 (en) 1982-12-24
IT8224974A1 (en) 1984-06-24

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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17P Request for examination filed

Effective date: 19830620

AK Designated contracting states

Designated state(s): CH DE FR GB LI

STAA Information on the status of an ep patent application or granted ep patent

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18W Application withdrawn

Withdrawal date: 19850111

RIN1 Information on inventor provided before grant (corrected)

Inventor name: VACHA, LUBOS, JOSEF, BOHUSLAV