DEVICE AND METHOD FOR PRODUCEING A FIBERGLASS PREFORM

Abstract

Device for producing a glass fiber preform, comprising a reaction cavity (1), a clamping mechanism (2) and a drive mechanism (3), wherein the clamping mechanism (2) is arranged in the reaction cavity (1) and is designed for attaching a target rod (4) and the drive mechanism (3) is designed to drive the clamping mechanism (2) so that it rotates about a vertical axis and moves up and down along a vertical direction, wherein several partitions (5) are arranged in the reaction cavity (1) and the several partitions (5) divide the reaction cavity (1) into a first chamber (11), a second chamber (12) and a third chamber (13); wherein each of the multiple partition walls (5) has a through-hole which is designed to be arranged coaxially to the target rod (4) so ​​that the target rod (4) can be arranged in the first chamber (11), the second chamber (12) or the third chamber (13) after it has been moved along the vertical direction; wherein the first chamber (11) is designed to deposit a loose body onto the target rod (4) using an axial vapor deposition (VAD) process; wherein the second chamber (12) is designed to perform a dehydration treatment and a sintering treatment on the loose body, so that a glass fiber preform (10) is obtained; and wherein the third chamber (13) is designed to carry out an annealing treatment on the glass fiber preform (10); wherein the multiple partitions (5) are made of flexible material and an opening diameter of the through-hole located on each of the multiple partitions (5) is less than a diameter of the loose body or a diameter of the glass fiber preform (10), such that the multiple partitions (5) engage with the loose body or the glass fiber preform (10) with an interference fit.

Description

TECHNICAL AREA

[0001] The present invention relates to the technical field of glass fiber production, for example a device and a method for producing a glass fiber preform. BACKGROUND

[0002] With increasing competition in the optical fiber market, ever higher demands are being placed on the quality of the fibers. In an optical fiber manufacturing process, the quality of the fiber preform directly influences the performance and a parameter index of the optical fiber product.

[0003] Fiberglass preform manufacturing generally comprises two manufacturing processes.

[0004] One manufacturing process involves producing a mandrel and an outer sheath separately and then fitting the corresponding outer sheath or mandrel to a parameter of the mandrel or outer sheath using standard processes and methods, such as the RIC (Rod in Cylinder) process. This type of manufacturing process has the advantage of allowing the production of a large-diameter fiberglass preform. However, the following problems can arise when joining the mandrel and the outer sheath: parameter mismatch, the introduction of contaminants into the joining process, and defects such as susceptibility to scratches during transport or joining.

[0005] In a further manufacturing process, a loose body (also known as a flimsy body or carbon black body) of the glass fiber preform is produced, and this loose body is then sintered into a glass fiber preform in a sintering process. Common methods such as modified chemical vapor deposition (MCVD), axial vapor deposition (VAD), and outside vapor deposition (OVD) are used. This manufacturing process avoids the problem of the glass fiber preform being susceptible to scratches and other defects during transport. However, this manufacturing process requires the glass fiber preform to be transported between different fixtures during various processes such as deposition and sintering.Since the glass fiber preform is in contact with the outside air during the transport process and the ambient temperature changes abruptly, the glass fiber preform can be affected by the fact that impurities adhere to it or cracks form on the rod due to stress fluctuations during temperature changes, which severely impairs the quality of a later glass fiber product and does not contribute to reducing glass fiber attenuation and improving the strength of the glass fiber.

[0006] Devices and methods for manufacturing glass fiber preforms are known from US 2002 / 0078714A1, JP H04-321533A and CN 111116037A. SUMMARY

[0007] The object of the invention is to provide an improved device for the production of glass fiber preforms and an improved method for the production of glass fiber preforms.

[0008] The problem is solved by a device according to claim 1 and a method according to claim 10.

[0009] The present invention provides a device and a method for manufacturing a glass fiber preform. The device enables the production of a glass fiber preform based on a VAD (Variable Output Deposition) process. In this manufacturing process, the glass fiber preform does not need to be moved between different devices, which improves the quality of the glass fiber preform and also significantly increases production efficiency.

[0010] The present invention provides a device for producing a glass fiber preform. The manufacturing device comprises a reaction cavity, a clamping mechanism, and a drive mechanism, wherein the clamping mechanism is arranged in the reaction cavity and is designed for attaching a target rod, and the drive mechanism is designed to drive the clamping mechanism so that it rotates about a vertical axis and moves up and down along a vertical direction.

[0011] Several partitions are arranged in the reaction cavity, and these partitions divide the reaction cavity into a first chamber, a second chamber and a third chamber, arranged sequentially from bottom to top.

[0012] Each of the multiple partition walls has a through-hole that is arranged coaxially to the target rod, so that the target rod can be located in the first chamber, the second chamber or the third chamber after it has been moved along the vertical direction.

[0013] The first chamber is designed to deposit a loose body onto the target rod using a VAD process.

[0014] The second chamber is designed to perform a dehydration treatment and a sintering treatment on the loose body, so that a glass fiber preform is obtained.

[0015] The third chamber is designed to perform an annealing treatment on the glass fiber preform.

[0016] Furthermore, the multiple partitions are made of flexible material and the opening diameter of the through-hole located on each of the multiple partitions is less than the diameter of the loose body or the diameter of the glass fiber preform, so that the multiple partitions engage with the loose body or the glass fiber preform with an interference fit.

[0017] Furthermore, a method for manufacturing a glass fiber preform using the above-mentioned apparatus for manufacturing a glass fiber preform is provided. The method comprises the steps described below.

[0018] The target rod is positioned in the first chamber and a loose body is deposited onto the target rod using a VAD method in the first chamber.

[0019] The target rod is lifted, and in the second chamber, a dehydration treatment and a sintering treatment are performed on the loose body, so that a glass fiber preform is obtained.

[0020] The glass fiber preform is raised further and an annealing treatment is carried out on the glass fiber preform in the third chamber. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a structural diagram of a device for producing a glass fiber preform according to an embodiment of the present invention. Fig. Figure 2 is a schematic representation of a suitable structure between a partition wall made of rigid material and a glass fiber preform according to an embodiment not according to the invention. Fig. Figure 3 is a schematic representation of a suitable structure between a partition wall made of flexible material and a glass fiber preform according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described below together with drawings and embodiments. Specific embodiments described here serve only to illustrate the present invention.

[0022] Unless expressly stated otherwise or limited, in the description of the present invention the terms "connected," "connected," and "attached" are to be understood in a broad sense, e.g., as permanently connected, detachably connected, or integrated; mechanically connected or electrically connected; directly connected or indirectly connected via an intermediate element; or internally connected between two components or interaction connections between two components. Specific meanings of the preceding terms in the present invention are to be understood based on the specific situation.

[0023] In the present invention, when a first feature is described as being "on" or "under" a second feature, the first feature and the second feature may, unless expressly stated otherwise or limited, be in direct contact or in contact via another feature between the two features, rather than being in direct contact. Furthermore, when the first feature is described as being "on" or "above" the second feature, the first feature lies directly on, above, or above the second feature, or the first feature lies obliquely on, above, or above the second feature, or the first feature simply lies on a higher plane than the second feature.If the first feature is described as being "under" the second feature, "below" the second feature, or "below" it, then the first feature is directly under or below the second feature, or the first feature is diagonally under or below the second feature, or the first feature is simply on a lower level than the second feature.

[0024] In the description of the present embodiment, orientations or positional relationships referred to by terms such as "upper," "lower," and "perpendicular" are based on orientations or positional relationships shown in the drawings. These orientations or positional relationships serve only to facilitate the description and simplify the processes, and not to indicate or imply that a device or element referred to must have such specific orientations or be designed or operated in such specific orientations. Therefore, these orientations or positional relationships are not to be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only to distinguish between the descriptions and have no special meaning.

[0025] With reference to Fig. Figure 1 of the present embodiment provides a device for manufacturing a glass fiber preform. The manufacturing device comprises a reaction cavity 1, a clamping mechanism 2, and a drive mechanism 3. The clamping mechanism 2 is arranged in the reaction cavity 1 and is designed to secure a target rod 4, and the drive mechanism 3 is designed to drive the clamping mechanism 2 so that it rotates about a vertical axis and moves up and down along a vertical direction. Several partitions 5 are arranged in the reaction cavity 1, and the partitions 5 divide the reaction cavity 1 into a first chamber 1, a second chamber 12, and a third chamber 13, which are arranged sequentially from bottom to top.Each of the multiple partition walls 5 has a through-hole arranged coaxially to the target rod 4, so that the target rod 4 can be located in the first chamber 11, the second chamber 12 or the third chamber 13 after it has been moved along the vertical direction.

[0026] The first chamber 11 is designed to deposit a loose body onto the target rod using a VAD process.

[0027] The second chamber 12 is designed to perform a dehydration treatment and a sintering treatment on the loose body, so that a glass fiber preform 10 is obtained.

[0028] The third chamber 13 is designed to perform an annealing treatment on the glass fiber preform 10.

[0029] Deposition: A process in which raw materials for a glass fiber are subjected to a chemical reaction in a specific environment to produce doped quartz glass.

[0030] Sintering: A process in which a hollow glass tube, after deposition, is gradually fired under a specific heat source to form a solid glass rod. Using the structure described above, the manufacturing device completes the deposition, dehydration, sintering, and annealing process of the glass fiber preform 10 through the reaction cavity 1, directly producing a vitrified end product of the glass fiber preform 10.The glass fiber preform 10 does not need to be transported between different devices during a manufacturing process. This prevents the glass fiber preform 10 from coming into contact with the outside air and accumulating contaminants, thus improving the doping purity of the glass fiber preform 10, preventing sudden temperature fluctuations caused by transport, minimizing internal stresses caused by temperature fluctuations during the process, and preventing problems such as rod cracking. The manufacturing device can be used, for example, in the production of extremely low-attenuation glass fibers, high-strength glass fibers, and specialty glass fibers.

[0031] In the present embodiment, the reaction cavity 1 can be a hollow cylinder, with a heating device (not shown) and a temperature sensor (not shown) arranged inside the reaction cavity 1 to create a high-temperature environment suitable for manufacturing the glass fiber preform 10. A circulating water pump (not shown) can be arranged outside the reaction cavity 1 to meet a cooling requirement. A cavity cover (not shown), which can close or open the reaction cavity 1, is arranged on the reaction cavity 1, allowing the target rod 4 to be moved into the reaction cavity 1 or the target rod 4, which carries the glass fiber preform 10, to be moved out of the reaction cavity 1.

[0032] A burner 6 is arranged inside the first chamber 11 and includes a lamp for mandrel deposition and a lamp for jacket deposition. A feed system (not shown), connected to the first chamber 11 from outside the reaction cavity 1, can supply high-purity SiCl4 and other dopants to the first chamber 11. Furthermore, a gas distribution system (not shown), connected to the first chamber 11, the second chamber 12, and the third chamber 13, can supply protective gas to the first chamber 11, the second chamber 12, and the third chamber 13, thereby forming a protective gas atmosphere in the first chamber 11, the second chamber 12, and the third chamber 13.

[0033] The clamping mechanism 2 includes a chuck designed for fastening the target rod 4.

[0034] The drive mechanism 3 comprises a first power assembly 31 and a second power assembly 32. The first power assembly 31 includes a leadscrew 311 extending from the upper region of the reaction cavity 1 along the vertical direction into the third chamber 13, and a lower end of the leadscrew 311 is rotatably connected to a holder 312, which is fixedly connected to a cavity wall of the reaction cavity 1 corresponding to the third chamber 13, with an upper end of the leadscrew 311 being connected to a synchronous pulley mechanism 313, which is driven by a first electric motor 314. In one embodiment, the leadscrew 311 can also be located outside the chamber.The second power assembly 32 comprises a lifting base 321, which is screwed to the leadscrew 311, and a second electric motor 322, which is attached to the lifting base 321. The lifting base 321 is designed for movement along the vertical direction, a rotating shaft of the second electric motor 322 is arranged parallel to the vertical direction, and one end of the rotating shaft of the second electric motor 322 is attached to the chuck. By means of the above-mentioned structure, the drive mechanism 3 can drive the chuck so that it rotates about the vertical axis and moves up and down along the vertical direction, thus positioning the aiming bar 4 in the first chamber 11, the second chamber 12, or the third chamber 13.

[0035] The above structures of the clamping mechanism 2 and the drive mechanism 3 are merely exemplary descriptions in this embodiment, whereby a mechanism with the same or a similar technical effect may be designed on the basis of the prior art, which is not limited here.

[0036] In the present embodiment, the manufacturing device further comprises a control system 7, wherein the control system 7 comprises a control module and an information acquisition module. The control module comprises a programmable logic controller (PLC) and an operator console, and the like. The information acquisition module comprises a position sensor (not shown) and an online monitoring device (not shown, may include a temperature sensor, a flow meter, a laser rangefinder, and the like), which are arranged in the first chamber 11, the second chamber 12, and / or the third chamber 13.The information acquisition module can provide information acquired by the information acquisition module to the control module, such as the position of one end of the loose body, a working speed, a working distance, a diameter of the glass fiber preform 10, a transmittance of the glass fiber preform 10, a deposition feed rate, and a gas flow rate of an oxyhydrogen flame of the burner 6. Based on the above information, the control module can set the start / stop and operating states of components such as the heating device, the feed system, the gas distribution system, the burner 6, and the drive mechanism 3 in the manufacturing device, thus controlling the deposition rate of the loose body, the temperature of a sintering chamber, and the like. This enables the linking and switching between processes, such as deposition and sintering in the process for manufacturing the glass fiber preform 10.

[0037] In the control system 7 described above, the control module and the information acquisition module were implemented using the VAD method in the device for manufacturing the glass fiber preform 10. Therefore, the components and circuit / communication structures used in control system 7 are not repeated here. For the manufacturing process carried out using the manufacturing device provided in this embodiment, a specific information acquisition and processing process required by control system 7 is described using the case described below.

[0038] With reference to Fig. 2 In this embodiment, the multiple partitions 5 can be made of a rigid material such as metal, and the opening diameter of the through-hole located on each of the multiple partitions 5 is correspondingly smaller than the diameter of the loose body or the diameter of the glass fiber preform 10, so that the multiple partitions 5 engage with the loose body or the glass fiber preform 10 with an interference fit. In one embodiment, the opening diameter of a through-hole on a first partition 51 is smaller than the diameter of the loose body, the opening diameter of a through-hole on a second partition 52 is smaller than the diameter of the glass fiber preform 10, and the opening diameter of a through-hole on a third partition 53 is smaller than the diameter of the glass fiber preform 10.

[0039] If the loose body / glass fiber preform 10 is located simultaneously in two or even three chambers, for example, if an upper half of the loose body is located in the second chamber 12 and a lower half of the loose body is located in the first chamber 11, the first partition 51, which is located between the first chamber 11 and the second chamber 12, lies close to the loose body, so that the first chamber 11 and the second chamber 12 are separated and form an independent atmospheric environment, which simplifies the further deposition of the loose body located in the first chamber 11 on a floor of the first chamber 11 and the loose body located in the first chamber 11 can be dehydrated or sintered.

[0040] The multiple flexible partitions 5 can be made of ceramic fiber. The ceramic fiber has properties such as high temperature resistance, low thermal conductivity, low dimensional weight, long service life, high tensile strength, good elasticity, and non-toxicity, and does not produce any volatile substances when heated, so that the quality of the glass fiber preform 10 is not affected.

[0041] If a flexible material is used for the multiple partitions 5, in one embodiment the difference between the diameter of the glass fiber preform 10 and the opening diameter of the through-hole can be less than 3 mm to ensure that the loose body / glass fiber preform 10 can be guided smoothly through the through-hole.

[0042] With reference to Fig. 3 In an optional embodiment, the multiple partitions 5 can also be made of a flexible material, and a preset gap is arranged between the through-hole located on each of the multiple partitions 5 and the loose body or glass fiber preform 10, thus ensuring that the loose body obtained by deposition does not scratch the first partition 51 when passing through it between the first chamber 11 and the second chamber 12. Furthermore, it is ensured that the glass fiber preform 10 obtained by sintering does not scratch the second partition 52 when passing through it between the second chamber 12 and the third chamber 13. The preset gap can be 1 to 3 mm.In one embodiment, the preset gap located between the through-hole on each of the multiple partitions 5 and the loose body or the glass fiber preform 10 can be as follows: a preset gap is located between the through-hole on the first partition 51 and the loose body, a preset gap is located between the through-hole on the second partition 52 and the glass fiber preform 10, and a preset gap is located between the through-hole on the third partition 53 and the glass fiber preform 10.

[0043] Since in one embodiment the diameter of the loose body / glass fiber preform 10 changes in the treatment processes such as deposition, dehydration and sintering, the opening diameter of the through-hole arranged on each of the several partition walls 5 can be adjusted accordingly, in contrast to through-holes with identical opening.

[0044] Furthermore, if a rigid material is used for the multiple partitions 5, i.e., a gap is formed between the loose body / glass fiber preform 10 and the multiple partitions 5, the first chamber 11 is connected to the second chamber 12. This does not mean, however, that the first chamber 11 and the second chamber 12 cannot operate simultaneously. For example, if the first chamber 11 is performing the deposition treatment, the second chamber 12 can perform the sintering treatment or even the dehydration treatment simply by introducing the protective gas into the second chamber 12. The reaction atmosphere of the first chamber 11 is not affected by the protective gas flowing from the second chamber 12 into the first chamber 11.

[0045] Thus, in this embodiment, a rigid material can be selected for the first partition 51 and the third partition 53 between the first chamber 11 and the second chamber 12, and the second chamber 12 and the third chamber 13 can be made of flexible material.

[0046] If, prior to the deposition treatment, the height difference between the lowest position, where the target bar 4 is lowered, and the first partition 51 is less than the total length of the loose body, the aforementioned case can occur during the deposition treatment process, since the target bar 4 is raised, in which the loose body is simultaneously located in the first chamber 11 and the second chamber 12, i.e., the lower half of the loose body is in the first chamber 11 and the upper half of the loose body is in the second chamber 12, thus enabling the first chamber 11 and the second chamber 12 to simultaneously perform the deposition treatment and the dehydration treatment, or the deposition treatment and the sintering treatment, to improve production efficiency.

[0047] If the first chamber 11 has a sufficient height such that the height difference between the lowest position in which the target rod 4 is lowered and the first partition 51 is greater than the total length of the loose body, the loose body can be lifted into the second chamber 12 to be dehydrated or sintered after the entire loose body has been obtained by deposition in the first chamber 11.

[0048] In one embodiment, the multiple partitions 5 are arranged in the second chamber 12, the multiple partitions 5 divide the second chamber 12 into a sintering chamber 121 and a dehydration chamber 122, which are connected in the upward and downward direction, the sintering chamber 121 is designed to carry out the sintering treatment on the loose body, and the dehydration chamber 122 is designed to carry out the dehydration treatment on the loose body.

[0049] In one embodiment, the height of the sintering chamber 121 and / or the dehydration chamber 122 is less than the total length of the loose body, so that the sintering chamber 121 and the dehydration chamber 122 can simultaneously perform the sintering treatment and the dehydration treatment.

[0050] In one embodiment, the height of the second chamber 12 is less than the total length of the loose body, so that the first chamber 11, the sintering chamber 121 and the dehydration chamber 122 can simultaneously perform the deposition treatment, the sintering treatment and the dehydration treatment respectively.

[0051] In one embodiment, the height of the sintering chamber 121 and the height of the dehydration chamber 122 are greater than the total length of the loose body, so that the loose body can be completely dehydrated in the dehydration chamber 122 or completely sintered in the sintering chamber 121.

[0052] In one embodiment, the height of the third chamber 13 is greater than the total length of the glass fiber preform 10, so that the glass fiber preform 10 can be completely annealed in the third chamber 13.

[0053] In one embodiment, the multiple partitions 5 are made of rigid material, and the preset gap is located between the through-hole, which is located on each of the multiple partitions 5, and the loose body or glass fiber preform 10.

[0054] In one embodiment, the multiple partitions 5 are made of flexible material, and the opening diameter of the through-hole located on each of the multiple partitions 5 is correspondingly smaller than the diameter of the loose body or the diameter of the glass fiber preform 10, so that the multiple partitions 5 engage with the loose body or the glass fiber preform 10 with an interference fit.

[0055] In one embodiment, the multiple partition walls 5 consist of a ceramic fiber.

[0056] In one embodiment, the third partition 53 is arranged in the second chamber 12, the third partition 53 divides the second chamber 12 into the sintering chamber 121 and the dehydration chamber 122, which are connected in the upward and downward directions, and the sintering chamber 121 is designed for carrying out the sintering treatment on the loose body and the dehydration chamber 122 is designed for carrying out the dehydration treatment.

[0057] In one embodiment, the height of the sintering chamber 121 and / or the height of the dehydration chamber 122 can be less than the total length of the loose body, so that the sintering chamber 121 and the dehydration chamber 122 can perform the sintering treatment and the dehydration treatment simultaneously to improve production efficiency.

[0058] In one embodiment, the sum of the heights of the sintering chamber 121 and the dehydration chamber 122 can be less than the total length of the loose body, so that the first chamber 11, the sintering chamber 121 and the dehydration chamber 122 can simultaneously perform the deposition treatment, the sintering treatment or the dehydration treatment.

[0059] In one embodiment, the height of the third chamber 13 is greater than the total length of the glass fiber preform 10, so that the glass fiber preform 10 can be completely annealed in the third chamber 13 to ensure that stresses in different parts of the entire glass fiber preform 10 are reduced simultaneously during annealing.

[0060] In one embodiment, the heights of the first chamber 11, the second chamber 12, and the third chamber 13, and even the heights of the sintering chamber 121 and the dehydration chamber 122, which are joined to form the second chamber 12, can each be adjusted to be greater than the total length of the loose body / glass fiber preform 10, so that the deposition, dehydration, sintering, and annealing treatments can be carried out separately. The heights of the first chamber 11, the second chamber 12, and the third chamber 13 can be selected adaptively based on a manufacturing requirement, the foregoing being merely an exemplary description.

[0061] A user can thus adaptively adjust the height of the multiple chambers based on a process requirement for the glass fiber preform to be produced, the time components consumed by deposition, dehydration, sintering and annealing treatments, and the like, so that the manufacturing device is suitable for continuous production.

[0062] The manufacturing device and a manufacturing process are described below using a case study. case

[0063] With reference to Fig.In this case, a reaction cavity 1 comprises a deposition chamber (a first chamber 11), a dehydration chamber 122, a sintering chamber 121 (which together with the dehydration chamber 122 forms a second chamber 12), and an annealing chamber (a third chamber 13), arranged sequentially from bottom to top. The sum of the heights of the deposition chamber, the dehydration chamber 122, and the sintering chamber 121 is less than the total length of a glass fiber preform 10 to be produced, and the height of the annealing chamber is greater than the total length of the glass fiber preform 10 to be produced.

[0064] A method for producing the glass fiber preform using the manufacturing device is described below, based on a VAD process.

[0065] An upper part of a target rod 4 is attached to a chuck to ensure that the target rod 4 is in a vertical position, the target rod 4 is moved into the reaction cavity 1 and then the reaction cavity 1 is closed, and a drive mechanism 3 drives the target rod 4 so that it moves downwards until a lower end of the target rod 4 is in the deposition chamber.

[0066] A control system 7 controls a feeding system such that raw materials, such as SiCl4 and other dopants, are fed to a mandrel deposition lamp and a shell deposition lamp according to a preset throughput value. The mandrel deposition lamp is ignited first, producing a powder consisting mainly of SiO2, which is sprayed onto the target bar 4 to form a mandrel section. Subsequently, the shell deposition lamp is ignited and sprays outside the mandrel to form a shell. Simultaneously, the control system 7 controls the drive mechanism 3 to rotate and raise the target bar 4 to produce a loose body with a specific shell-to-core ratio and diameter that increases in size along an axial direction of the target bar 4.

[0067] In a process for manufacturing the loose body, information such as the position of one end of the loose body, the working speed, the working distance, the diameter of the glass fiber preform 10, the transmittance of the glass fiber preform 10, the deposition feed rate, and the gas flow of an oxyhydrogen flame of a burner 6 are continuously monitored by a position sensor and an online monitoring device as a basis for the control system 7, so that the setting of parameters such as the flame temperature of the burner 6, the rotation and lifting speed of the drive mechanism 3, the feed rate, the temperature, and the gas atmosphere of the deposition chamber are controlled.

[0068] When the target rod 4 is lifted, the loose body enters the dehydration chamber 122. Upon receiving a measurement signal from the position sensor located in the dehydration chamber 122, the control system 7 activates a heating device within the dehydration chamber 122, heating it to 1300°C to dehydrate the loose body. The hydroxyl content in the rod after dehydration is less than or equal to 10 ppb.

[0069] As the target rod 4 is raised further, the dehydrated loose body enters the sintering chamber 121. When the control system 7 receives a measurement signal transmitted by the position sensor located in the sintering chamber 121, the control system 7 activates a heating device in the sintering chamber 121, causing the dehydration chamber 122 to heat to 1500°C for sintering. During sintering, a gas distribution system introduces helium into the sintering chamber 121 to maintain a normal pressure of approximately 100 Pa, with the option of introducing a fluorine-containing gas for fluorine permeation treatment. Sintering under reduced pressure can be used for the shell.In this case, no gas is introduced, and pumping is performed to maintain a vacuum, generally 0.01 Pa or less, thus eliminating any trapped bubbles remaining in the glass fiber preform 10 after vitrification, improving the quality of the glass fiber preform, and reducing the duration of subsequent annealing treatment. A glass fiber preform 10 with a diameter greater than 90 mm, a mandrel and jacket of good quality, and a minimum relative refractive index of -0.006 is sintered.The online monitoring device arranged in the sintering chamber 121 records parameters such as the transmittance of the sintered glass fiber preform 10, so that it is easier for the control system 7 to control the rotation and lifting speed of the drive mechanism 3 on the basis of the above parameters and to set a deposition speed and the gas atmosphere in the deposition chamber and the like, thereby ensuring the quality of the glass fiber preform 10.

[0070] As the target rod 4 is lifted, the sintered glass fiber preform 10 fully enters the annealing chamber for the annealing treatment. In a high-temperature environment, the gas distribution system introduces a protective gas such as helium or nitrogen into the annealing chamber, thereby reducing internal stress in the glass fiber preform 10 and preventing it from cracking due to excessive stress. This process ultimately forms a large glass fiber preform 10 with a length exceeding 2000 mm.

[0071] The obtained high-quality glass fiber preform 10 is moved out of the reaction cavity 1 and the glass fiber preform 10 is removed.

[0072] In a deposition treatment process, the loose body lifted into the dehydration chamber 122 and even into the sintering chamber 121 can be subjected to dehydration treatment or sintering treatment simultaneously, and considering that the rate of deposition treatment is lower than that of dehydration treatment and sintering treatment, both dehydration treatment and sintering treatment can be carried out intermittently.

[0073] The annealing treatment can be carried out in the annealing chamber after the sintering of the entire loose body to form the glass fiber preform 10 is completed, thus ensuring that during annealing the entire glass fiber preform 10 is fully subjected to annealing and that the stresses of different parts of the entire glass fiber preform 10 are reduced simultaneously, thereby preventing uneven stress relief in the different parts of the glass fiber preform 10.

[0074] Optionally, the above-mentioned protective gas can be argon, which has good thermal conductivity, in addition to helium, as the reaction atmosphere.

[0075] This embodiment further provides a method for producing a glass fiber preform using the above manufacturing device. The method comprises the steps described below.

[0076] The target rod 4 is arranged in the first chamber 11, and a loose body is deposited onto the target rod 4 in the first chamber 11 using a VAD process.

[0077] The target rod 4 is lifted, and in the second chamber 12 a dehydration treatment and a sintering treatment are carried out on the loose body, so that a glass fiber preform 10 is obtained.

[0078] The glass fiber preform 10 is raised further and an annealing treatment is carried out on the glass fiber preform 10 in the third chamber 13.

[0079] One embodiment of the method essentially corresponds to the above case, which will not be repeated here. Reference symbol list 1 reaction cavity 11 first chamber 12 second chamber 121 Sinter chamber 122 Dehydration chamber 13 Third Chamber 2 clamping mechanism 3 Drive mechanism 31 first power module 311 Lead screw 312 holders 313 Synchronous belt pulley mechanism 314 first electric motor 32 second power module 321 Lifting base 322 second electric motor 4 Target stick 5 partition wall 51 first partition wall 52 second partition wall 53 third partition wall 6 burners 7 Control system 10 Glass fiber preforms

Claims

Device for producing a glass fiber preform, comprising a reaction cavity (1), a clamping mechanism (2), and a drive mechanism (3), wherein the clamping mechanism (2) is arranged in the reaction cavity (1) and is designed for attaching a target rod (4), and the drive mechanism (3) is designed to drive the clamping mechanism (2) so that it rotates about a vertical axis and moves up and down along a vertical direction, wherein several partitions (5) are arranged in the reaction cavity (1), and the several partitions (5) divide the reaction cavity (1) into a first chamber (11), a second chamber (12), and a third chamber (13);wherein each of the multiple partition walls (5) has a through-hole configured to be coaxial with the target rod (4), so that the target rod (4) can be located in the first chamber (11), the second chamber (12), or the third chamber (13) after being moved along the vertical direction; wherein the first chamber (11) is designed to deposit a loose body onto the target rod (4) using an axial vapor deposition (VAD) process; wherein the second chamber (12) is designed to perform a dehydration treatment and a sintering treatment on the loose body to obtain a glass fiber preform (10); and wherein the third chamber (13) is designed to perform an annealing treatment on the glass fiber preform (10);wherein the multiple partitions (5) are made of flexible material and an opening diameter of the through-hole located on each of the multiple partitions (5) is less than a diameter of the loose body or a diameter of the glass fiber preform (10), such that the multiple partitions (5) engage with the loose body or the glass fiber preform (10) with an interference fit. Manufacturing apparatus according to claim 1, wherein the multiple partitions (5) are arranged in the second chamber (12), the multiple partitions (5) divide the second chamber (12) into a sintering chamber (121) and a dehydration chamber (122) which are connected in an upward-downward direction, and the sintering chamber (121) is designed to carry out the sintering treatment on the loose body and the dehydration chamber (122) is designed to carry out the dehydration treatment on the loose body. Manufacturing apparatus according to claim 2, wherein the height of the sintering chamber (121) and / or the dehydration chamber (122) is less than the total length of the loose body, so that the sintering chamber (121) and the dehydration chamber (122) can simultaneously perform the sintering treatment and the dehydration treatment. Manufacturing apparatus according to claim 3, wherein the height of the second chamber (12) is less than the total length of the loose body, so that the first chamber (11), the dehydration chamber (122) and the sintering chamber (121) can simultaneously perform a deposition treatment, the dehydration treatment and the sintering treatment. Manufacturing apparatus according to claim 2, wherein both the height of the sintering chamber (121) and the height of the dehydration chamber (122) are greater than the total length of the loose body, so that the loose body can be completely dehydrated in the dehydration chamber (122) or completely sintered in the sintering chamber (121). Manufacturing apparatus according to claim 1, wherein the height of the third chamber (13) is greater than the total length of the glass fiber preform (10), so that the glass fiber preform (10) can be completely annealed in the third chamber (13). Manufacturing apparatus according to one of claims 1 to 6, wherein the multiple partitions (5) consist of a ceramic fiber. Manufacturing device according to claim 1, wherein the drive mechanism (3) comprises a first power assembly (31) and a second power assembly (32); wherein the first power assembly (31) comprises a lead screw (311) extending from an upper region of the reaction cavity (1) along the vertical direction into the third chamber (13), a lower end of the lead screw (311) rotatably connected to a holder (312) which is fixedly connected to a cavity wall of the reaction cavity (1) corresponding to the third chamber (13), and an upper end of the lead screw (311) is in transmission connection with a synchronous pulley mechanism (313) which is driven by a first electric motor (314); and wherein the second power assembly (32) comprises a lifting base (321) which is screwed to the lead screw (311) and a second electric motor (322) attached to the lifting base (321). Manufacturing apparatus according to claim 1, further comprising a control system (7), wherein the control system (7) comprises a control module and an information acquisition module, the control module comprising a programmable logic controller (PLC) and an operator console, and the information acquisition module comprising a position sensor and an online monitoring device arranged in the first chamber (11) and / or in the second chamber (12) and / or in the third chamber (13); wherein the information acquisition module is designed to provide at least one of the following information being acquired to the control module: a position of an end of the loose body, a working speed, a working distance, a diameter of the glass fiber preform (10), a transmittance of the glass fiber preform (10), a deposition feed rate, and a gas flow of an oxyhydrogen flame of the burner (6);and wherein the control module is designed to set start / stop and operating states of the adjustable heating device, a feed system, a gas distribution system of the burner (6) and the drive mechanism (3) in the device for producing the glass fiber preform according to the information, so that a deposition quantity of the loose body and a temperature of a sintering chamber are controlled. A method for producing a glass fiber preform using the apparatus for producing the glass fiber preform according to any one of claims 1 to 9, comprising: arranging the target rod (4) in the first chamber (11) and depositing a loose body onto the target rod (4) in the first chamber (11) using an axial vapor deposition (VAD) method; lifting the target rod (4) and performing a dehydration treatment and a sintering treatment on the loose body in the second chamber (12) so that a glass fiber preform (10) is obtained; and further lifting the glass fiber preform (10) and performing an annealing treatment on the glass fiber preform (10) in the third chamber (13).

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