Repair processing method of sleeve preform

Abstract

The invention discloses a repair processing method of a sleeve preform, which comprises the steps of perforation, water-based cleaning fluid cleaning, acid pickling, ventilation drying, sealing treatment and vacuumizing wiredrawing, by adopting the repair method, the whole fusion shrinkage conical head of the sleeve is effectively prevented from being cut off, the operation process is short, the waste of raw materials is less, the cost is low, and the repair processing method is suitable for large-scale popularization and application. The repaired part can be used as the turning part of the subsequent secondary wire drawing, and the tapering treatment does not need to be performed again, so that a large amount of propane and oxygen cost can be saved, and meanwhile, the bursting risk caused by uneven heating in the casing tapering process can be effectively reduced; in addition, by the adoption of the method, the subsequent secondary assembly process of the core rod and the sleeve can be avoided, and the attenuation problem and the strength problem caused by scratches generated in the assembly process and secondary pollution are avoided.

Description

Technical Field

[0001] The invention relates to a method for repairing a sleeve preform rod, and belongs to the technical field of optical fiber manufacturing. Background Art

[0002] As the most important carrier of communication transmission, optical fiber plays an irreplaceable role in the field of communication. Optical fiber preform is the mother material for preparing optical fiber, and its quality determines the quality of optical fiber to a large extent. At present, the production process of optical fiber preform mainly adopts a two-step method, which generally manufactures optical fiber preform first and then manufactures the cladding of optical fiber preform. Typical outer cladding preparation technologies include external vapor deposition method, sleeve method, plasma spraying method, etc. Among them, the sleeve method has become the mainstream preparation method in the market due to its large size, long length, great improvement of production efficiency, and cost advantage. In the process of preparing optical fiber by the sleeve method, it is often necessary to repair it due to material defects, size changes, improper process flow, etc. In this process, it is generally necessary to cut the cone head that has been melted, take out the sleeve and core rod and process them separately, and then re-grind the cone and pull the cone on the sleeve. This operation is often accompanied by a large amount of raw material loss, and a large amount of propane and oxygen are consumed during the processing process. In addition, the completed part is prone to breakage during the cone pulling process, resulting in larger-scale rework and repair problems, which greatly increases the production cost of optical fiber and reduces production efficiency. When the sleeve material inspection is qualified, the main reason for the unqualified optical fiber parameters is the interface contamination problem during the sleeve and core rod assembly operation. The use of conventional cutting, taper grinding, and taper pulling processes will seriously affect the production cycle, ultimately affecting the delivery time and increasing production costs. Summary of the invention

[0003] The purpose of the present invention is to provide a method for repairing a sleeve preform rod to solve the above technical problems.

[0004] The technical solution to achieve the purpose of the present invention is: a method for repairing a casing preform specifically comprises the following steps:

[0005] S1: Fix the repaired casing preform rod and drill a single-side through hole in the unmelted area of ​​the repaired tube;

[0006] S2: drilling another single-side through hole on the opposite side of the single-side through hole, so that the casing preform rod has a double-side through hole;

[0007] S3: cleaning the perforated casing preform in a water-based cleaning solution;

[0008] S4: performing pickling treatment on the casing preform rod that has completed water-based cleaning;

[0009] S5: drying the casing preform rod that has completed the pickling treatment by passing N2 to remove impurity gases, and then drying it;

[0010] S6: sealing the casing preform rod;

[0011] S7: Hang the sealed casing preform tail tube on a drawing tower for vacuum drawing.

[0012] The repair method uses drilling and liquid flushing methods to repair the side of the unmelted area of ​​the repaired casing, which effectively avoids cutting off the entire melted cone head of the casing. The operation process is short and the waste of raw materials is small. The repaired part can be used as the turning part of the subsequent secondary wire drawing. It does not need to be re-coned, which can save a lot of propane and oxygen costs, and can effectively reduce the risk of bursting caused by uneven heating during the cone drawing process of the casing. In addition, the method can also avoid the subsequent secondary assembly process of the core rod and the casing, and avoid the attenuation problem caused by scratches and secondary pollution generated during the assembly process.

[0013] Further or optionally, in order to match the size of the preform in the production process and prevent the optical fiber preform from breaking during the drilling process, the diameter of the drill bit in step S1 is 5 to 10 mm.

[0014] Further or optionally, in order to improve the cleaning efficiency and reduce cleaning residues, an ultrasonic cleaning device is used in the water washing process in step S3, and the concentration of the water-based cleaning solution is 1-2%.

[0015] Further or optionally, in order to control the amount of sleeve corrosion and the optical parameters of the finished optical fiber, the acid solution in the pickling process in step S4 is 20%-30% HF acid or 20%-30% HF acid and 2%-5% HNO3 to form a mixed acid solution, and the sleeve corrosion amount is 0.4-0.8mm. Within this corrosion range, the early contamination on the surface of the core rod can be effectively removed to prevent impurity particles and metal ions from diffusing into the core rod during the subsequent firing process. Under the premise of ensuring that the internal radius of the core rod does not change drastically, the optical performance of the finished product after drawing meets the performance requirements.

[0016] Further or optionally, in order to prevent water vapor from causing attenuation and strength performance of optical fiber drawing, during the drying process in step S5, dry N2 gas enters the inner wall of the sleeve from the tail pipe and flows out from the hole punched at the cone head of the sleeve, and the drying time is 36 to 48 hours.

[0017] Further or optionally, in order to improve the vacuuming efficiency and further improve the internal cleanliness and reduce residual water vapor, clean N2 gas needs to be introduced during the sealing process in step S6 to prevent internal water vapor from remaining during sealing; during the vacuuming process, a vacuum pumping device is used to check the sealing of the casing, and the negative pressure is controlled to -0.1MPa.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The optical fiber preform cleaning method of the present invention uses drilling and liquid flushing methods to repair the unmelted area of ​​the repaired sleeve, which effectively avoids cutting off the entire melted cone head of the sleeve. The operation process is short and the waste of raw materials is small. The repaired part can be used as the turning part of the subsequent secondary drawing. It does not need to be re-tapered, which can save a lot of propane and oxygen costs. At the same time, it can effectively reduce the risk of explosion caused by uneven heating during the cone drawing process of the sleeve. In addition, the use of this method can also avoid the subsequent secondary assembly process of the core rod and the sleeve, avoiding the attenuation problem caused by scratches and secondary pollution generated during the assembly process.

[0020] (2) The optical fiber preform repair method of the present invention limits the drill bit size to 5 to 10 mm, effectively avoiding the preform bursting problem caused by an oversized drill bit.

[0021] (3) The present invention uses ultrasonic cleaning equipment for cleaning and limits the concentration of water-based cleaning liquid to 1-2%. It has high cleaning efficiency, less residue, and little effect on optical fiber parameters.

[0022] (4) The present invention limits the acid composition and the amount of corrosion of the sleeve, and effectively controls the optical parameters of the finished optical fiber by limiting the parameters. Compared with other cleaning methods, the quality of the finished optical fiber is more stable.

[0023] (5) The optical fiber preform of the present invention is dried with N2 and the ventilation time is controlled, and a subsequent drying treatment is performed, which can effectively prevent water vapor from entering the preform and prevent the drawing process from affecting the attenuation performance and strength performance of the optical fiber.

[0024] (6) The present invention performs negative pressure vacuuming during the sealing process, which can further prevent water vapor from remaining and achieve higher cleanliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0026] Figure 1 It is a schematic diagram of the process of the present invention.

[0027] Figure 2Schematic diagram of the traditional casing preform repair process.

[0028] Figure 3 It is a schematic diagram of punching holes in the repair process of the sleeve preform rod of the present invention.

[0029] Among them, 1 is casing, 2 is tail tube, 3 is core rod, 4 is original cone head of casing preform, 5 is cone head of casing preform repaired secondary cone, and 6 is side holes. DETAILED DESCRIPTION

[0030] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0032] All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0033] (Example 1)

[0034] See Figure 1 In this embodiment, a method for repairing a sleeve preform is provided, comprising the following steps:

[0035] S1, placing the repaired casing preform rod 1 on a drilling lathe, selecting a drill bit with a suitable diameter and aligning it with the side of the unmelted area of ​​the repaired casing preform rod 1 to drill a hole until a hole 7 is formed through one side;

[0036] Furthermore, the symmetrical side of the hole of the sleeve preform rod 1 is also drilled to form a double hole 7 penetrating therethrough;

[0037] Furthermore, the drill bit has a diameter of φ5-10 mm;

[0038] S2, placing the casing preform 1 in an ultrasonic cleaning device for cleaning to remove impurities and oil stains inside and outside the casing preform 1;

[0039] Furthermore, the ultrasonic cleaning equipment is configured with a water-based cleaning agent solution with a concentration of 1-2%;

[0040] S3, placing the casing preform rod 1 in a pickling device for acid treatment to remove metal particle impurities;

[0041] Furthermore, the acid solution is configured with 20%-30% HF acid or 2%-5% HNO3 is added to form a mixed acid solution;

[0042] Furthermore, the corrosion amount of the sleeve preform rod 1 during acid treatment is 0.4-0.8 mm;

[0043] S4, drying the casing preform 1, using clean N2 to pass into the inner wall of the casing from the tail pipe, and flowing out from the side holes 7 of the casing preform to form a passage;

[0044] Furthermore, the drying time of the sleeve preform rod 1 is 36-48 hours to ensure that all the water vapor in the inner hole of the sleeve preform rod 1 is completely overflowed;

[0045] S5, sealing the dried casing preform rod 1, using a hydrogen-oxygen flame hand lamp to melt the clean quartz mandrel and then plug the hole 7 punched by the casing cone head;

[0046] Furthermore, clean N2 may be introduced into the tail pipe during the sealing process to prevent water vapor from appearing in the inner hole of the casing preform rod 1 during the sealing process;

[0047] Furthermore, the sealing performance of the casing sealing hole was checked using a vacuum device, and the negative pressure reached -0.1MPa;

[0048] S6. The sealed casing preform rod 1 is directly hung on the drawing tower, and the tail tube is vacuumed and drawn normally.

[0049] It should be understood that the present invention is described by some embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope of protection of the present invention.

Claims

1. A method for repairing a casing preform, comprising the following steps: S1: Fix the repaired casing preform rod, and punch a single-side through hole in the unmelted area of ​​the repaired tube; then punch another single-side through hole on the opposite side of the single-side through hole, so that the casing preform rod forms a double-side through hole; S2: cleaning the perforated casing preform in a water-based cleaning solution; S3: performing pickling treatment on the casing preform rod that has completed water-based cleaning; S4: Drying the casing preform rod after pickling by passing N2 to remove impurity gas, and then drying it; S5: sealing the casing preform rod; S6: Hang the sealed casing preform tail tube on a drawing tower for vacuum drawing.

2. A method for repairing a sleeve preform according to claim 1, characterized in that: In step S1, the diameter of the drill bit is 5 to 10 mm.

3. The method for repairing a sleeve preform according to claim 1, characterized in that: In the water washing process in step S2, an ultrasonic cleaning device is used, and the concentration of the water-based cleaning solution is 1-2%.

4. The method for repairing a sleeve preform according to claim 1, characterized in that: In the pickling process in step S3, the acid solution is 20%-30% HF acid or 20%-30% HF acid and 2%-5% HNO3 to form a mixed acid solution, and the sleeve column corrosion amount is 0.4-0.8mm.

5. The method for repairing a sleeve preform according to claim 1, characterized in that: During the drying process in step S4, dry N2 gas enters the inner wall of the casing from the tail pipe and flows out from the holes punched at the casing cone head. The drying time is 36 to 48 hours.

6. The method for repairing a sleeve preform according to claim 1, characterized in that: In the step S5, clean N2 gas needs to be introduced during the sealing process to prevent internal water vapor from remaining during sealing; during the vacuuming process, a vacuuming device is used to check the sealing of the casing, and the negative pressure is controlled to be -0.1MPa.

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