CN1761629A - Synthetic silica glass tube for the production of a preform, method for producing the same in a vertical drawing process and use of said tube - Google Patents
Synthetic silica glass tube for the production of a preform, method for producing the same in a vertical drawing process and use of said tube Download PDFInfo
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- CN1761629A CN1761629A CN 200480007714 CN200480007714A CN1761629A CN 1761629 A CN1761629 A CN 1761629A CN 200480007714 CN200480007714 CN 200480007714 CN 200480007714 A CN200480007714 A CN 200480007714A CN 1761629 A CN1761629 A CN 1761629A
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- silica glass
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- pipeline
- glass tube
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- 238000000034 method Methods 0.000 title claims abstract description 75
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 60
- 230000008569 process Effects 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title abstract description 10
- 230000003746 surface roughness Effects 0.000 claims abstract description 5
- 238000010926 purge Methods 0.000 claims description 38
- 239000000758 substrate Substances 0.000 claims description 27
- 238000005406 washing Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 230000009467 reduction Effects 0.000 claims description 8
- 230000008021 deposition Effects 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 5
- 229910052801 chlorine Inorganic materials 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 4
- 239000002019 doping agent Substances 0.000 claims description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 238000000605 extraction Methods 0.000 claims description 3
- YZCKVEUIGOORGS-OUBTZVSYSA-N Deuterium Chemical compound [2H] YZCKVEUIGOORGS-OUBTZVSYSA-N 0.000 claims description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims description 2
- 229910005793 GeO 2 Inorganic materials 0.000 claims description 2
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 2
- 229910052805 deuterium Inorganic materials 0.000 claims description 2
- 229910052731 fluorine Inorganic materials 0.000 claims description 2
- 239000011737 fluorine Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 5
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 2
- 230000002000 scavenging effect Effects 0.000 abstract 3
- 239000002344 surface layer Substances 0.000 abstract 3
- 239000010453 quartz Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 46
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 22
- 229910001873 dinitrogen Inorganic materials 0.000 description 18
- 238000005516 engineering process Methods 0.000 description 10
- 239000012535 impurity Substances 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 9
- 238000000576 coating method Methods 0.000 description 9
- 229910004298 SiO 2 Inorganic materials 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 239000011521 glass Substances 0.000 description 6
- 238000000151 deposition Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 239000013307 optical fiber Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000004071 soot Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- 238000004611 spectroscopical analysis Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000012797 qualification Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 230000001447 compensatory effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000008141 laxative Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001543 purgative effect Effects 0.000 description 1
- 238000009738 saturating Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
Classifications
-
- 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
-
- 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
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
- C03B37/018—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01884—Means for supporting, rotating and translating tubes or rods being formed, e.g. lathes
- C03B37/01892—Deposition substrates, e.g. tubes, mandrels
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/02—Pure silica glass, e.g. pure fused quartz
- C03B2201/03—Impurity concentration specified
- C03B2201/04—Hydroxyl ion (OH)
Abstract
Known synthetic quartz glass tubes for the production of a preform have an inner bore with a surface layer produced without using tools in the molten state and an inner zone. The aim of the invention is to provide a tube which does not release any OH groups to the surroundings. For this purpose, the surface layer (30) has a thickness of 10 mu m and an average OH content of not more than 5 ppm by weight and an average surface roughness Ra of not more than 0.1 mu m. The inner zone (34) that starts on the surface layer (30) and terminates 10 mu m before the outer wall has an average OH content of not more than 0.2 ppm by weight. A simple and inexpensive method for producing a quartz tube of the above type is to continuously draw a tube strand from a softened quartz glass mass in a vertical drawing process. A scavenging gas is circulated through the inner bore of the tube, said gas having a water content of less than 100 ppb per weight. The front end of the tube strand (19) is closed by a flow obstacle (26) that is permeable to the scavenging gas and that reduces the amount of scavenging gas (23) flowing through.
Description
The present invention relates to be used to produce the synthetic silica glass tube of precast body, the interior region that this pipe has inner chamber, wall of the outer-rotor and extends between inner chamber and wall of the outer-rotor, wherein inner chamber has the upper layer that produces when not having tool in contact under molten state.
In addition, the present invention relates to produce the method for synthetic silica glass tube with vertical drawing process, wherein the silica glass piece is sent to the heating zone continuously, and it is softening therein, extract pipeline continuously out from softening zone, and the inner chamber wash cycles gas by pipe, obtain silica glass tube by being cut to certain-length from it.
In addition, the present invention relates to the suitable purposes of silica glass tube.
In the method that is called MCVD (improvement chemical vapour deposition) of producing the optical fiber prefabricating body, in the so-called substrate tube inside of pure silicon dioxide glass by vapour deposition SiO
2With doping SiO
2Layer, this is normally known.The substrate tube of inner coating comprises that wherein sedimentary layer is compressed and is drawn into optical fiber subsequently.Usually, apply other clad material before wire drawing or in the drawing process.
When light was propagated, optical mode not only was directed in fiber cores but also in the coating zone.Although decay to the outside intensity exponentially that in the coating zone, guides, depend on optical fiber designs, must guarantee wherein not comprise the impurity that can in being used for the wavelength region of light transmission, cause strong additional attenuation.
Be described among the DE19852704A1 according to the silica glass tube of the above-mentioned type and its production method.Known method begins with the production soot tube, by flame hydrolysis SiCl
4Produce SiO
2Particle and rotating carrier the layer in deposited particles, just produce porous SiO
2Soot tube.In order to reduce hydroxyl, the soot tube that produces is in such a way at high temperature carried out chlorine handle, vitrifying then, thereby the synthetic silica glass tube of formation hollow to value less than 30wtppb.Make the smooth surface and the chemical milling of hollow with mechanical means.The last size of the pretreated in such a way hollow that stretches then to substrate tube.Thereby obtain being characterised in that high purity and do not have the soot tube of the slippery inner surface that tool in contact produces when molten state, described internal surface is particularly suitable for inner coating in the MCVD method subsequently.
Although this moment, commercially available substrate tube was made up of the synthetic high-purity silicon dioxide glass that produces, they comprise impurity.When the fade performance to optical fiber has high request, they thereby on limited degree, only be suitable for as directly around the clad material of core segment.Usually, on the inwall of substrate tube, therefore at first deposit coating zone, inside, only after this, deposit the layer in core zone after a while with highest purity.When substrate tube is compressed into plug, in drawing process subsequently, still to reach a high temperature, owing to this impurity may be diffused in the inner coating zone from substrate tube, even enter the core zone.It is especially crucial that hydrogen and above-mentioned whole OH ion become.Be diffused into SiO easily
2The harmful effect of the hydrogen of matrix is that it can combine with matrix oxygen again, thereby forms OH
-Base.
In order to alleviate described problem, suggestion should produce the added diffusion barrier layer that comprises Vanadium Pentoxide in FLAKES in the inside of substrate tube among the CA2335879A1.Diffusion barrier stops the OH ion diffusion to go out substrate tube in inner coating zone.But, this technology relative complex.
Also known for example by mechanical mill, by chemical milling or remove the internal surface of substrate tube by plasma etching.Although removed on the upper layer or the partial impurities that wherein comprises, described method is slow relatively, and can produce other impurity or surface imperfection.Method for selective etching has deleterious especially effect.Especially for long etching cycle, these methods cause uneven removing, and have therefore damaged the surface and destroyed the favourable surface tissue that produces in the molten state, and therefore can negative impact be arranged to further MCVD technology.
In addition, all are removed method and substantially all run into such problem, and promptly the thickness of the contaminated upper layer that should suitably remove can change with situation is different, and can not definitely learn usually.
Therefore, the purpose of this invention is to provide and have the synthetic silica glass tube that produces the surface when not having tool in contact, this Guan Buhui shows with OH base and discharges the cheap and simple method that this silica glass tube is produced in relevant above-mentioned defective and explanation.
As for silica glass tube, reach the described purpose that begins from above-mentioned silica glass tube according to the present invention, wherein upper layer has the thickness and the average OH content that is no more than 5wtppm of 10 μ m, wherein be no more than the average surface roughness Ra of 0.1 μ m, and the interior region that starts from the upper layer and terminate in the preceding 10 μ m of wall of the outer-rotor has the average OH content that is no more than 0.2wtppm.
Find when using known silica glass tube, although nominally low OH content is arranged, but still go wrong, thereby can only be owing to the OH content that increases.The nominal OH content of silica glass tube utilizes spectroscopy to measure to determine on whole wall thickness usually.Find that at present in this measuring method, the OH base that comprises in the upper layer is difficult to be noted, even exist with high density in thin upper layer.
If clearly do not indicate in addition, the following observation that upper layer is carried out relates to the layer in abutting connection with the silica glass tube inner chamber, and it is to prepreg manufacture and be key especially for the MCVD method especially.Silica glass tube is included in the interior region that extends between upper layer and the wall of the outer-rotor.Interior region is material character zone relatively uniformly, and its both sides limit by wall of the outer-rotor, and wall of the outer-rotor may comprise impurity near surface.In order to get rid of the impurity of this near surface in the interior region qualification, all be the thickness that each surface (being respectively inwall and wall of the outer-rotor) adds 10 μ m at every turn.Interior region also is called as " main body " hereinafter.
Silica glass tube of the present invention shows three basic sides:
1. on the one hand, it demonstrates the low OH content that is no more than 0.2wtppm in material of main part, preferably be no more than 0.1wtppm.Therefore avoided the absorption of OH base, therefore the optical mode that has intensity in the coating zone also decays not too strongly.
Information about OH content in the main body is meant the average OH content that utilizes spectroscopy determining.
2. in addition, upper layer all has low average OH content up to the degree of depth of 10 μ m.In upper layer, can in the silica glass tube production technique, form the OH base.Common weak bond of these OH bases is incorporated into SiO
2On the network, and can enter into owing to the high temperature in the drawing process on the optics in the more effective fiber area, and therefore can cause optical fiber attenuation.The content that this weak bond closes the OH base in the upper layer should keep low as far as possible, in any case but lowly in upper layer, comprise the average OH content that is no more than 5wtppm, preferably be no more than 1wtppm.
The machinery of aforesaid upper layer or chemistry are removed so are no longer needed, thereby have avoided relevant effort and changed relevant above-mentioned defective with possible surface.Still utilize spectroscopy promptly by the OH content in the difference measurement mensuration upper layer.
3. the aspect as 2. silica glass tubes of the present invention that illustrate allows to use the silica glass tube preparation to have the precast body that does not have the surface of tool in contact under molten state.It is particularly suitable for by MCVD method inside deposition SiO
2Layer.Produce the upper layer of silica glass tube of the present invention with drawing process.This upper layer essential characteristic is low surface roughness, and uses the R that is no more than 0.1 μ m on meaning of the present invention
aValue defined.Surfaceness R
aDefinition follow EN ISO 4287/1.
Available crucible drawing process or prepare silica glass tube by the stretching hollow.
In order to prepare the combining light index distribution, synthetic silica glass preferably is doped with fluorine, GeO
2, B
2O
3, P
2O
5, Al
2O
3, TiO
2The doping agent of form or the combination of described doping agent.
As for method, reach the above-mentioned purpose that begins from aforesaid method according to the present invention, wherein use the purge gas of water-content less than 100wtppb, the front end of pipeline can thoroughly and have been reduced by the flow obstacle of its mobile purgative gas scale of construction and sealed purge gas.
In the method for the invention, purge gas is circulated continuously by the inner chamber of the pipeline extracted out.Find therefore to have stoped the deposition on inwall, even can discharge impurity.
On the other hand,, use the purge gas of water-content, thereby cleaning itself is difficult to introduce any hydroxyl ion in the silica glass of inwall less than 100wtppb according to the present invention.
Because purge gas is introduced in the inner chamber and can overflows in the bottom of pipeline, has therefore guaranteed the successive cleaning.But,, freely overflow from inner chamber is uncrossed because the front end of pipeline, has therefore prevented purge gas by flow obstacle sealing that can be saturating to purge gas according to the present invention.In vertical drawing process without any instrument, main interior pressure and be important process control parameter in the inner chamber from the pressure reduction between the external pressure of external action.In technology controlling and process, described pressure reduction or interior pressure for example are used for control tube wall thickness or pipe diameter.Interior flow volume qualification of pressing main by purge gas.For freely flowing out, need high gas throughput to be used to adjust predetermined interior pressure.Compare with the technology that does not have flow obstacle, reduced the gas throughput of the high purity purge gas of technology controlling and process needs according to flow obstacle provided by the invention, so this has the effect that reduces cost.Flow obstacle is made up of gaseous state, liquid or solid plug in partially enclosed inner chamber or the contraction inner chamber.
Preferably, use the purge gas of water-content less than 30wtppb.
The water-content of purge gas is low more, and it is just few more that the OH base enters into the pipeline inner wall surface.
As for flow obstacle, confirmed when described obstacle be useful when being projected into plug in the pipeline inner chamber and forming, plug dwindles the cross section of unrestricted flow purge gas.
For example, plug is projected into the inner chamber from the free front end of pipeline, preferably is cut to the top, zone of certain-length up to silica glass tube.Pipeline is cut to certain-length can produce insignificant variation at the most in technology controlling and process.Plug is made of porous materials, or it has at least one continuous perforate.
As same preferred possibility, flow obstacle is formed by the gas curtain that acts on the pipeline front end.
In order to produce gas curtain, use high-pure gas, thereby pollution problem can in cavity region, not occur.In addition, this technology characteristics is easy processing.By obtaining gas curtain at the air-flow that is transverse on the direction of extracting the pipeline longitudinal axis out.It produces the pressure to the effect of outflow purge gas, thereby has reduced the flow of purge gas by it.
Economy as for method, confirmed that be favourable like this time, promptly with begin from front end to be sent to continuously the heating zone and therein the form of part remollescent hollow the silica glass piece is provided in batches, and when softening zone is extracted pipeline out continuously, hollow is stretched at least 5 times of its initial length, preferably at least 20 times.
Silica glass hollow with vertical drawing process stretching large volume not only allows to produce pipe at an easy rate, and is created in the desirable internal surface that does not have tool in contact just to form in the molten state.Utilize the ratio of elongation that increases between hollow and the pipe, can more easily adjust required surface quality.
Confirmed that when purge gas comprises the gaseous state siccative be particularly advantageous during chlorine-containing gas especially.
The gaseous state siccative is made up of Halogen especially chlorine-bearing compound usually.Remaining water reaction in they and purge gas and the upper layer, thus realize the special effective dry of pipe internal surface.
In addition, it is favourable before having confirmed to work as in being incorporated into the pipeline inner chamber purge gas being carried out drying process.
Drying process by machinery or chemical means realized purge gas and the water that wherein comprises with the separating of other objectionable impurities such as hydrocarbon.The machinery means comprise for example to be introduced in the appropriate filter that purge gas is trapped to water molecules.
Preferably, purge gas is no more than 80l/min (standard liter/min) by the volumetric flow rate of inner chamber.
The inwall of pipeline is warm more, and the required surface that produces in molten state is just smooth more.But purge gas can be realized the cooling of inner chamber, and this impairs the formation of required smooth surface.Find, be up under the volumetric flow rate of 80l/min that described cooling effect still can keep being low to moderate surface quality and not be damaged in observable mode.In order to reach this condition, consider interior pressure predetermined by technology controlling and process and that must keep, it is necessary using flow obstacle in inner chamber, this is above illustrating.
Exterior washings gas preferably flows around the outer covering layer of the pipeline in the zone, heating zone, and purge gas is as exterior washings gas.
In this case, around pipeline wall of the outer-rotor mobile purge gas with identical around inwall mobile purge gas.Therefore, wall of the outer-rotor is difficult to load the OH base, and this has produced in inner chamber and all have the silica glass tube of low OH content on wall of the outer-rotor.
According to the purpose purposes of silica glass tube, the quality in the wall of the outer-rotor zone there is lower requirement than the quality of inwall.In this case, confirmed that the pipeline wall of the outer-rotor flows in the zone, exterior washings gas-circulating heating zone, and the water-content of purge gas is particularly advantageous during than low at least 10 times of the water-content of exterior washings gas.
Owing to used with purge gas to compare the lower exterior washings gas of purity requirement, therefore can reduce consuming cost.When using exterior washings gas, to be cooled to when being lower than 900 ℃ temperature be useful especially for for some time coating of growing at least like this to such an extent as to confirmed to flow outer covering layer when described gas-circulating pipeline.
Therefore prevented that outer covering layer from high temperature contacting with moisture atmosphere such as air.Be higher than under 900 ℃ the temperature, may have to expect has the OH of certain degree base to be attached in the silica glass matrix.Exterior washings gas also causes the faster cooling of pipeline outer covering layer here.
Also confirm when in addition to silica glass tube under at least 900 ℃ temperature in anhydrous atmosphere or to carry out in a vacuum that the OH reduction handles be particularly advantageous.
Because the OH reduction is handled, the OH content in the surf zone can all be lowered on the inwall and on wall of the outer-rotor after a while.
About this point, confirmed particularly advantageous when OH reduction processing is included in the processing that contains in the deuterium atmosphere.
In this OH reduction was handled, the OH base of existence was replaced by the OD base, and it does not produce any absorption band in the wavelength region that is used for optical data transmission at present.
The silica glass tube that silica glass tube of the present invention and the method according to this invention produce is particularly useful for inside deposition SiO in the MCVD method
2The substrate tube of layer usefulness.
To illustrate in greater detail the present invention in conjunction with embodiment and accompanying drawing now.Accompanying drawing is shown in detail in:
Fig. 1 is for to become silica glass tube to come the embodiment synoptic diagram of production substrate tube by the hollow with vertical drawing process stretching silica glass;
Fig. 2 is the diagram OH content distribution plan on the substrate tube wall that produces of different modes in the diagram, i.e. Fig. 2 a and Fig. 2 b, and Fig. 2 a be that Fig. 2 b is in substrate tube produced according to the invention in the substrate tube according to prior art production.
Fig. 1 has shown method of the present invention and has been suitable for realizing the embodiment of the device of this method.Device comprises vertically arranged stove 1, and it can be heated to the temperature more than 2300 ℃, and comprises the graphite heating element.
The longitudinal axis 3 vertically is sent to stove 1 with the hollow 2 of synthetic silica glass from above.The inner chamber 4 of hollow 2 is in the above by plug 5 sealings.Purge gas line 6 is incorporated in the inner chamber 4 by filling in 5.Cleaning pipeline 6 finishes in process vessel 7, process vessel 7 is connected on the nitrogen pipeline 11 by gas tube 8 with by strainer 10 (Messer Griesheim GmbH " Hydrosorb "), gas tube 8 can be closed by stopping valve 9, and nitrogen pipeline 11 has under meter and control device 15.Nitrogen gas stream enters into inner chamber 4 by pipeline 6,8,11, and its supply is represented with orienting arrow 23.The water-content that is incorporated into the nitrogen gas stream in the inner chamber 4 is 10wtppb.
For compensatory pressure changes, process vessel 7 is equipped with the by-pass valve 13 that can open and close in addition.When open mode, portion gas flows out from process vessel 7 unchangeably, thereby is caused or the flow condition that produces owing to other reason only changes suddenly the pressure change in the process vessel 7 is had local influence by the control behavior.
The lower front end 19 of pipeline 21 is by plug 26 sealings, and plug 26 has the central through hole 25 that diameter is 4mm.The flow of nitrogen gas stream 23 is reduced to about 30 standard liter/min by filling in 26, depends on the setting of technology controlling and process.
In order to prevent oxidation in the stove zone, the especially fusion loss of other graphite parts in graphite heating element and the stove 1, stove by shell 14 around, shell 14 comprises nitrogen gas stream 24 imports and outlet 22, utilizes space between its hollow 2 and the stove inwall by continuous wash.Nitrogen gas stream 24 has identical quality with nitrogen gas stream 23, and two nitrogen gas stream 23,24 are taken from identical source.
Outlet 22 forms the end of cooling channels 27, and is extending on the length of 1 meter of the bottom side of stove 1 as the part of shell 14 in the mode of cover cooling channel 27, and nitrogen gas stream 24 portion within it flows along the outer covering layer of extracting pipeline 21 out.Here the length that designs cooling channel 27 makes pipeline 21 have only about 600 ℃ temperature when entering in the air in the zone of outlet 22 leaving.Low surface temperature has prevented that the OH base is attached in the silica glass.
The typical process of the inventive method is described in more detail referring now to Fig. 1.
Hollow 2 has the external diameter of 150mm and the wall thickness of 40mm.After stove 1 is heated to its required about 2300 ℃ temperature, mobile hollow 2, bottom 19 enters into stove 1 from above, and roughly is being softened in the position at stove 1 middle part.Simultaneously, the bottom 19 of hollow 2 is drawn out of from stove 1, because it is clamped and remove by being drawn out of to separate first glass block plug.Subsequently, hollow 2 is reduced continuously with the lowering speed of 11mm/min, removes softening end 19 by releasing with the speed of 640mm/min, and forming internal diameter is that 22mm and external diameter are the pipeline of 28mm.
In drawing process, exsiccant nitrogen gas stream 23 is incorporated into inner chamber 4 by purge gas line 6 in strainer 10.Before being introduced in strainer, nitrogen gas stream 23 has purity level 4.0 (〉=99.99%), shows the residual water-content of 10wtppb then.
In the inner wall area of inner chamber 4, impurity is discharged by nitrogen gas stream 23.But, because the very low water content of 10wtppb still can keep the OH base to the interior introducing of the thermal silicon dioxide glass of pipeline inwall as small as possible.
Be approximately normal atmosphere at furnace interior.The flow of setting nitrogen gas stream 23 by under meter and control device 15 arrives about 30 standard liter/min, presses thereby set in the substantially invariable 3mbar in inner chamber 4.In drawing process, press in the continuously measured, and readjust the flow of nitrogen gas stream 23 in view of the above.By using plug 26 to make low relatively flow velocity 30l/min is possible, because described plug has stoped freely flowing out of nitrogen gas stream 23.And this has such result, has promptly avoided the inwall of the silica glass tube of air-flow undercooling extraction, and has obtained slick melt surface, and this will further describe in conjunction with Fig. 2 hereinafter in more detail.
Control the external diameter and the wall thickness of the pipeline 21 of extraction by technology controlling and process.The interior pressure of using inner chamber 4 inside is as controlled variable, and pressure is the result of nitrogen gas stream 23 substantially, thereby under the dimensional change situation, can control the amount of nitrogen gas stream 23 by control unit.
In drawing process, open by-pass valve 13, thereby part nitrogen gas stream 23 will flow to the outside by valve 13, and not enter in the inner chamber 4 of Glass tubing 21.Therefore pressure change in the inner chamber 4 is weakened.When the closing condition of by-pass valve 13, the requirement of nitrogen gas stream 23 reduces about 50%.
The Glass tubing 21 that obtains of cutting is to suitable piece, and as on inwall, depositing SiO by the MCVD method
2The substrate tube of layer.To in conjunction with Fig. 2 the substrate tube that average surface roughness Ra is 0.06 μ m be described in more detail hereinafter.
Among Fig. 2 figure each all is the synoptic diagram that shows OH concentration distribution on the whole wall thickness of substrate tube.Fig. 2 a has shown the distribution in the substrate tube that obtains according to prior art, and Fig. 2 b is according to the distribution in the substrate tube of the present invention.
All on the y axle, draw OH content, at the radius of x plot on X axis substrate tube wall thickness with relative unit at every turn.r
iRepresent inwall, r
aRepresent the outer wall of substrate tube.All the with dashed lines 31 signal thickness that draws is 10 μ m (r at every turn
i+ 10 μ m) upper layer 30 in the inner wall area of locating, with dashed lines 33 thickness that draws is 10 μ m (r
a-10 μ m) upper layer 32 in the outer wall area of locating.Thickness extends between upper layer 30 and 32 for the interior region 34 of about 3.0mm.
Fig. 2 a) shows, from high level, the inside in upper layer 30 and 32 zones reduces the OH content in the substrate tube that produces according to standard method on each wall.Average OH content in upper layer 30 and 32 zones all is 7.4wtppm in each case, is 0.08wtppm in interior region 34.Upper layer 30 and relative high OH content in 32 zones are difficult to observe in all by radiographic X spectral measurement at the entire substrate pipe.By the average OH content in the spectrum difference measurement mensuration upper layer 30 and 32.
A) compare with Fig. 2, according to 2b) substrate tube of the present invention show that the average OH content in the interior region 34 also is about 0.08wtppm, but obvious lower OH content is arranged in upper layer 30 and 32 zones.The OH content mean value of measuring the there by the spectrum difference measurement is 0.8wtppm.Therefore substrate tube of the present invention is particularly suitable for producing by the MCVD method application of the layer of close fiber cores.
Claims (19)
1. synthetic silica glass tube that is used to produce precast body, the interior region that it has inner chamber, wall of the outer-rotor and extends between inner chamber and wall of the outer-rotor, wherein inner chamber has the upper layer that produces when not having tool in contact under molten state, be characterised in that upper layer (30) has the thickness of 10 μ m and is no more than the average OH content of 5wtppm and wherein is no more than the average surface roughness R of 0.1 μ m
a, and start from upper layer (30) and go up and terminate in the interior region (34) of the preceding 10 μ m of wall of the outer-rotor and have the average OH content that is no more than 0.2wtppm.
2. according to the silica glass tube of claim 1, be characterised in that the average OH content in the upper layer (30) is no more than 1wtppm.
3. according to the silica glass tube of claim 1 or 2, be characterised in that the average OH content in the interior region (34) is no more than 0.1wtppm.
4. according to silica glass tube any in the aforementioned claim, be characterised in that synthetic silica glass is doped with fluorine, GeO
2, B
2O
3, P
2O
5, Al
2O
3, TiO
2The doping agent of form or the combination of described doping agent.
5. method of producing synthetic silica glass tube with vertical drawing process, wherein the silica glass piece is sent to the heating zone continuously, and it is softening therein, extract pipeline continuously out from softening zone, and the inner chamber wash cycles gas by described pipe, obtain silica glass tube by being cut to certain-length from it, be characterised in that and use the purge gas (23) of water-content that the front end of pipeline (19) can thoroughly and have been reduced by the flow obstacle (26) of its mobile purge gas (23) amount and seal purge gas less than 100wtppb.
6. according to the method for claim 5, be characterised in that and use the purge gas (23) of water-content less than 30wtppb.
7. according to the method for claim 5 or 6, be characterised in that flow obstacle (26) is formed by the plug that is projected in the pipeline inner chamber and dwindle the cross section of unrestricted flow purge gas (23).
8. according to the method for claim 6 or 7, be characterised in that flow obstacle is produced by the gas curtain that acts on the pipeline front end.
9. according to method any in the preceding method claim, be characterised in that with begin from its front end to be sent to continuously heating zone (1) and therein the form of part remollescent hollow (2) the silica glass piece is provided, and from the continuous extraction in softening zone pipeline (21), hollow (2) is stretched at least 5 times of its initial length.
10. according to the method for claim 9, be characterised in that hollow (2) is stretched at least 20 times of its initial length.
11., be characterised in that purge gas (23) comprises gaseous state siccative, especially chlorine-containing gas according to method any in the preceding method claim.
12., before being characterised in that in being incorporated into pipeline inner chamber (4) purge gas (23) is carried out drying process according to method any in the preceding method claim.
13., be characterised in that the volumetric flow rate of the purge gas (23) by inner chamber (4) is no more than 80l/min according to method any in the preceding method claim.
14. according to method any in the preceding method claim, be characterised in that exterior washings gas (24) flows around the outer covering layer of pipeline (21) in the zone, heating zone (1), the water-content of purge gas (23) hangs down at least 10 times than the water-content of exterior washings gas (24).
15. according to method any in the claim 6 to 13, be characterised in that exterior washings gas (24) flows around the outer covering layer of pipeline (21) in the zone, heating zone (1), purge gas (23) is as exterior washings gas (24).
16. according to method any in claim 14 or 15, be characterised in that exterior washings gas (24) around pipeline (21) to such an extent as to the outer covering layer described line of for some time that flows at least be cooled to and be lower than 900 ℃ temperature.
17. according to method any in the preceding method claim, be characterised in that to silica glass tube under at least 900 ℃ temperature in anhydrous atmosphere or carry out OH reduction in a vacuum and handle.
18., be characterised in that OH reduction processing is included in the processing that contains in the deuterium atmosphere according to the method for claim 17.
19. the purposes of the silica glass tube that produces according to silica glass tube any in the claim 1 to 4 or according to method any one in the claim 5 to 18 is as inside deposition SiO in the MCVD method
2The substrate tube of layer usefulness.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10312760.7 | 2003-03-21 | ||
| DE10312760 | 2003-03-21 | ||
| DE10312543.4 | 2003-03-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1761629A true CN1761629A (en) | 2006-04-19 |
| CN100351192C CN100351192C (en) | 2007-11-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200480007714XA Expired - Lifetime CN100351192C (en) | 2003-03-21 | 2004-03-19 | Synthetic silica glass tube for the production of a preform, method for producing the same in a vertical drawing process and use of said tube |
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|---|---|
| CN (1) | CN100351192C (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101563299B (en) * | 2006-12-15 | 2014-05-28 | 赫罗伊斯石英玻璃股份有限两合公司 | A method for producing a hollow cylinder of synthetic quartz glass, and thickwalled hollow cylinder obtained according to the method |
| CN102089687B (en) * | 2008-07-07 | 2014-11-12 | 赫罗伊斯石英玻璃股份有限两合公司 | Bending-insensitive optical fiber, quartz glass tube as a semi-finished product for the manufacture thereof and method for the manufacture of the fiber |
| CN105358494A (en) * | 2013-07-12 | 2016-02-24 | 赫罗伊斯石英玻璃股份有限两合公司 | Method for producing a large quartz-glass pipe |
| CN108264216A (en) * | 2018-04-25 | 2018-07-10 | 蚌埠亘乐家庭用品有限公司 | A kind of glass pipe trombone slide molding machine |
| CN111995231A (en) * | 2020-09-03 | 2020-11-27 | 江苏亨通光纤科技有限公司 | Drawing equipment and method for deep fluorine-doped capillary tube for beam combiner |
| CN114007991A (en) * | 2019-07-17 | 2022-02-01 | 贺利氏石英玻璃有限两合公司 | Method for manufacturing hollow-core optical fiber and hollow-core optical fiber preform |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK0598349T3 (en) * | 1992-11-19 | 1999-04-26 | Shinetsu Quartz Prod | Process for producing a large quartz glass tube, as well as a preform and an optical fiber |
| DE69929152T2 (en) * | 1998-10-08 | 2006-08-24 | Heraeus Tenevo Gmbh | Method for producing a quartz glass preform for optical fibers and the quartz glass tube used therefor |
| KR100306381B1 (en) * | 1998-12-10 | 2001-11-30 | 윤종용 | Apparatus and method for manufacturing optical fiber matrix for condensation and closing of deposition tubes |
-
2004
- 2004-03-19 CN CNB200480007714XA patent/CN100351192C/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101563299B (en) * | 2006-12-15 | 2014-05-28 | 赫罗伊斯石英玻璃股份有限两合公司 | A method for producing a hollow cylinder of synthetic quartz glass, and thickwalled hollow cylinder obtained according to the method |
| CN102089687B (en) * | 2008-07-07 | 2014-11-12 | 赫罗伊斯石英玻璃股份有限两合公司 | Bending-insensitive optical fiber, quartz glass tube as a semi-finished product for the manufacture thereof and method for the manufacture of the fiber |
| CN105358494A (en) * | 2013-07-12 | 2016-02-24 | 赫罗伊斯石英玻璃股份有限两合公司 | Method for producing a large quartz-glass pipe |
| CN108264216A (en) * | 2018-04-25 | 2018-07-10 | 蚌埠亘乐家庭用品有限公司 | A kind of glass pipe trombone slide molding machine |
| CN114007991A (en) * | 2019-07-17 | 2022-02-01 | 贺利氏石英玻璃有限两合公司 | Method for manufacturing hollow-core optical fiber and hollow-core optical fiber preform |
| CN114007991B (en) * | 2019-07-17 | 2023-11-21 | 贺利氏石英玻璃有限两合公司 | Method for manufacturing hollow fiber and hollow fiber preform |
| CN111995231A (en) * | 2020-09-03 | 2020-11-27 | 江苏亨通光纤科技有限公司 | Drawing equipment and method for deep fluorine-doped capillary tube for beam combiner |
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|---|---|
| CN100351192C (en) | 2007-11-28 |
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