Optical fiber preform end face sealing equipment and method thereof

Abstract

The invention provides optical fiber preform end face sealing equipment and method, and the equipment comprises a flow guide pipe which is used for accommodating the end part of an optical fiber preform nesting pipe and forming a sealant circulation channel; the diffusion layer is arranged on the outer side of the flow guide pipe in a sleeving manner, and the diffusion layer comprises a pore structure capable of enabling injected sealant to form radial uniform laminar flow diffusion; the clamping assembly is detachably connected to the outer side of the diffusion layer, and the clamping assembly comprises a clamp which can be positioned and locked at the end part of the optical fiber preform nesting pipe; the axial adjusting and positioning device is configured to automatically form a preset clearance fit relation between the flow guide pipe and the optical fiber preform nesting pipe when the clamp reaches a preset sealing position; the sealing glue is uniformly diffused in the radial direction, bubbles can be eliminated, the positioning and gap adjusting precision is improved, the processing error of the end part of the nesting pipe of the optical fiber preform rod is automatically compensated, the gaps around the nesting pipe are completely and uniformly filled with the sealing glue, and the working effect and the air tightness are improved.

Description

Technical Field

[0001] This invention relates to the field of optical fiber preform technology, and specifically to an optical fiber preform end face sealing device and method. Background Technology

[0002] In the drawing process of hollow optical fiber preforms, the preforms, made of high-purity quartz glass tubes, need to undergo critical processes of high-temperature melting and gas pressurization. In order to form a stable microstructure cavity during the drawing process, a constant gas pressure must be applied inside the nested tube; if the seal on the end face of the preform fails, it will lead to leakage of pressurized gas, causing the cavity to collapse or the tube wall thickness to be uneven, resulting in a surge in transmission loss of the hollow optical fiber.

[0003] Before the fiber drawing process, the end face of the nested tube of the hollow optical fiber preform needs to be strictly sealed to prevent external contaminants from entering the microstructure pores. Traditional sealing processes have the following three major technical bottlenecks: 1. Microbubble defect problem Currently, the mainstream method uses manual application of sealant or simple mold injection. Due to the lack of laminar flow control mechanisms (such as the straight-through injection devices disclosed in existing technologies), the turbulent flow of the sealant causes air bubbles to become trapped. These micron-sized bubbles expand during the high-temperature drawing stage, causing microcracks inside the optical fiber and increasing the optical signal attenuation by 3-5 dB / km.

[0004] 2. Insufficient uniformity of sealing Current technology relies on operator experience to adjust the injection pressure, making it difficult to ensure uniform distribution of the adhesive within the annular gap of the nested tube. Asymmetric sealing layers can lead to excessive eccentricity of the fiber cladding; according to current technology, this defect reduces the fiber yield by approximately 12%.

[0005] 3. Positioning accuracy defects Traditional fixtures use mechanical hard positioning, which cannot automatically compensate for machining errors at the end face of the preform. When the gap between the nested tube and the guide tube exceeds 50μm, the sealant is prone to delamination. A 2025 test report from the US OFS laboratory shows that this can reduce the tensile strength of the optical fiber by more than 15%.

[0006] The above background information is disclosed only to assist in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application, nor does it necessarily provide technical teachings. In the absence of clear evidence, the novelty and inventiveness of the above application shall be deemed to be incomplete. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes an optical fiber preform end-face sealing device and method. The innovative design of the diffusion layer pore structure in conjunction with the axial adjustment and positioning device not only ensures uniform radial diffusion of the sealant, which helps eliminate air bubbles, but also improves positioning accuracy and gap adjustment accuracy. It automatically compensates for processing errors at the end of the optical fiber preform nested tube, ensuring that the sealant completely and uniformly fills the gap around the nested tube, thereby improving working efficiency and airtightness.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: On one hand, the present invention provides an optical fiber preform end face sealing device, comprising: The guide tube is used to accommodate the end of the fiber optic preform nested tube and form a channel for the flow of sealant. A diffusion layer is sleeved on the outside of the guide tube, and the diffusion layer contains a porous structure that enables the injected sealant to form a radially uniform laminar diffusion. A clamping assembly is detachably connected to the outside of the diffusion layer, the clamping assembly including a clamp capable of positioning and locking to the end of the fiber preform nested tube; The axial adjustment and positioning device is configured to automatically form a predetermined gap fit relationship between the guide tube and the fiber preform nesting tube when the clamp reaches the preset sealing position.

[0009] This invention proposes an optical fiber preform end face sealing device and method. The innovative design of the diffusion layer pore structure and the axial adjustment and positioning device not only makes the sealant diffuse radially uniformly, which is conducive to eliminating air bubbles, but also improves the positioning accuracy and gap adjustment accuracy. It automatically compensates for the processing error at the end of the optical fiber preform nested tube, so that the sealant completely and uniformly fills the gap around the nested tube, improving the working effect and airtightness.

[0010] As a preferred technical solution, the axial adjustment and positioning device includes: an axial adjustment mechanism, the axial adjustment mechanism comprising: An axial slide rail is provided at the bottom of the outer periphery of the clamp; A drive assembly that drives the clamp to move along the axial slide rail.

[0011] As a preferred technical solution, the fixture includes an adjustable clamping part, which is used to adapt to fiber optic preform nesting tubes of different thicknesses. The predetermined gap size between the flow guide tube and the fiber preform nesting tube is 0.1-1.5mm.

[0012] As a preferred technical solution, the axial adjustment and positioning device includes: a positioning detector, which is used to detect the preset sealing position of the end of the preformed rod nested tube in real time. The positioning detector is electrically connected to a first controller, which is electrically connected to a drive assembly. The first controller controls the drive assembly to drive the clamp to move along the axial slide rail and to position and lock the preset sealing position of the end of the preformed rod nested tube.

[0013] As a preferred technical solution, the pore structure includes: a filter screen and a mesh adjuster disposed on the filter screen, the mesh adjuster including an adjustment window corresponding to the mesh position of the filter screen.

[0014] As a preferred technical solution, it includes: a fluid parameter detection sensor, which is used to detect the viscosity of the sealant in real time, the fluid parameter detection sensor is electrically connected to a second controller, the second controller is electrically connected to the mesh adjuster, and controls the mesh adjuster to dynamically and automatically adjust the effective pore area of ​​the filter screen according to the sealant viscosity and the required flow rate.

[0015] As a preferred technical solution, a positioning and transmission tube is provided on the outer side of the diffusion layer, and the positioning and transmission tube is connected to an injection pump, which is used to inject sealant into the device.

[0016] On the other hand, the present invention provides a method for sealing the end face of an optical fiber preform, which is produced using the optical fiber preform end face sealing equipment as described in any of the preceding claims, and includes the following steps: S1 Inserts the end of the fiber preform nested tube into the guide tube to a predetermined depth; The S2 axial adjustment and positioning device works in conjunction with the clamping assembly to position and lock the clamp at the preset sealing position at the end of the fiber preform nested tube. S3 injects sealant into the equipment, and the sealant flows through the pore structure of the diffusion layer, forming a radially uniform laminar diffusion state under the action of the pore structure, so as to fill the circumferential gap of the preset sealing position with sealant. After the sealant has cured, release the clamps and remove the diffusion layer.

[0017] As a preferred technical solution, in step S2, the inner diameter of the guide tube and the outer diameter of the fiber preform nested tube form a clearance fit, with a clearance range of 0.1-1.5mm. The pore density of the pore structure in step S3 is 50-200 mesh, and the pore distribution uniformity deviation of the pore structure is ≤5%.

[0018] As a preferred technical solution, the predetermined depth in step S1 is 3-5 mm; In step S3, the injection rate of sealant into the equipment is 0.1-0.5 ml / min, and the injection time is 6-10 min.

[0019] The optical fiber preform end-face sealing device and method provided by this invention have the following beneficial effects: The innovative design of the diffusion layer pore structure in conjunction with the axial adjustment and positioning device not only enables the sealant to diffuse radially and uniformly, which helps to eliminate air bubbles, but also improves the positioning accuracy and gap adjustment accuracy. It automatically compensates for the processing error at the end of the fiber preform nested tube, so that the sealant can completely and uniformly fill the gap around the nested tube, improving the working efficiency and airtightness. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an optical fiber preform end face sealing device provided by the present invention; Figure 2 This is a partial structural schematic diagram of an optical fiber preform end face sealing device provided by the present invention; Figure 3 This invention provides a schematic diagram of the diffusion layer structure of an optical fiber preform end-face sealing device. Figure 4 This invention provides a schematic diagram of the circuit structure of an optical fiber preform end face sealing device. Figure 5 This invention provides another circuit structure schematic diagram of an optical fiber preform end face sealing device. Among them, 1-guide tube; 2-diffusion layer; 3-clamping assembly; 4-axial slide rail; 5-pore structure; 6-mesh adjuster; 7-positioning transmission tube; 8-filter screen. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] like Figures 1-3 As shown, the present invention provides an optical fiber preform end face sealing device, comprising: The guide tube 1 is used to accommodate the end of the fiber optic preform nested tube (not shown) and form a sealant flow channel; A diffusion layer 2 is sleeved on the outside of the guide tube 1. The diffusion layer 2 includes a porous structure 5 that enables the injected sealant to form a radially uniform laminar diffusion. The clamping assembly 3 is detachably connected to the outside of the diffusion layer 2. The clamping assembly 3 includes a clamp that can be positioned and locked to the end of the fiber preform nested tube (not shown). The axial adjustment and positioning device is configured to automatically form a predetermined gap fit relationship between the guide tube 1 and the fiber preform nesting tube (not shown) when the clamp reaches the preset sealing position.

[0023] This invention proposes an optical fiber preform end-face sealing device. The innovative design of the diffusion layer pore structure and the axial adjustment and positioning device not only makes the sealant diffuse radially uniformly, which is beneficial to eliminating air bubbles, but also improves the positioning accuracy and gap adjustment accuracy. It automatically compensates for the processing error at the end of the optical fiber preform nested tube, so that the sealant completely and uniformly fills the gap around the nested tube, improving the working efficiency and airtightness.

[0024] Preferably, such as Figures 1-2 As shown, the inner diameter of the guide tube 1 is either the same inner diameter or a stepped inner diameter.

[0025] Preferably, the fiber preform nesting tube is a single-layer fiber preform nesting tube or a double-layer fiber preform nesting tube.

[0026] Preferably, such as Figure 1 As shown, the axial adjustment and positioning device includes: an axial adjustment mechanism, the axial adjustment mechanism comprising: An axial slide rail 4 is provided at the bottom of the outer periphery of the clamp; A drive assembly (not shown) that drives the clamp to move along the axial slide rail 4; The precise axial displacement control of the fixture (not shown) is achieved through the cooperation of the axial slide rail 4 and the drive assembly (not shown); the linear movement of the axial slide rail 4 and the automated control of the drive assembly (not shown) can reduce manual intervention, ensure the consistency of the position of the object to be tested during multiple tests, and improve data repeatability.

[0027] Preferably, the clamp (not shown) includes an adjustable clamping part (not shown) for adapting to fiber optic preform nesting tubes (not shown) of different thicknesses; the adjustable clamping part (not shown) includes: An adjustable clamping gap elastic clamping mechanism (not shown); Stepped slots for multi-specification sleeves (not shown); The adjustable clamping part (not shown) can be compatible with fiber optic preform nesting tubes of different thicknesses by dynamically adjusting the clamping diameter, thus solving the problem of poor compatibility caused by the fixed size of traditional clamps. The predetermined gap size between the flow guide tube 1 and the fiber preform nesting tube (not shown) is 0.1-1.5mm. The gap size matches the viscosity of the sealant, which can form a stable laminar flow state, reduce colloid splashing or bubble residue caused by turbulence, and improve the filling density.

[0028] Preferably, such as Figure 4 As shown, the axial adjustment and positioning device includes: a positioning detector, which is used to detect the preset sealing position at the end of the preformed rod nested tube in real time. The positioning detector is electrically connected to a first controller, which is electrically connected to a drive assembly. The first controller controls the drive assembly to drive the clamp (not shown) to move along the axial slide rail 4 and to position and lock the preset sealing position at the end of the preformed rod nested tube (not shown). The positioning detector (such as an infrared displacement sensor or a visual recognition module) detects the preset sealing position signal at the end of the preformed rod nested tube (not shown) in real time. The first controller drives the clamp to move along the axial slide rail according to the detection signal and to position and lock the preset sealing position at the end of the preformed rod nested tube (not shown). This simplifies the manual intervention process, effectively avoids positioning deviation, and ensures the uniformity of sealant filling.

[0029] Preferably, such as Figure 3 As shown, the pore structure 5 includes: a filter screen 8 and a mesh size adjuster 6 disposed on the filter screen 8. The mesh size adjuster 6 includes an adjustment window corresponding to the mesh size of the filter screen. The adjustment window corresponds to the mesh size of the filter screen 8. The mesh size adjuster 6 changes the effective filtration area by sliding or rotating. It is compatible with various sealants with viscosities of 500-10000 cP, and can adjust the pore density of 50-200 mesh and the pore distribution uniformity deviation ≤5%. It can ensure that the sealant forms radial laminar diffusion and avoid local accumulation caused by turbulence.

[0030] Preferably, such as Figure 5 As shown, the system includes: a fluid parameter detection sensor, which is used to detect the viscosity of the sealant in real time; the fluid parameter detection sensor is electrically connected to a second controller, which is electrically connected to the mesh adjuster; the second controller controls the mesh adjuster to dynamically and automatically adjust the effective pore area of ​​the filter screen according to the sealant viscosity and the required flow rate; the second controller is configured to: receive the sealant viscosity detection signal, calculate the pore area corresponding to the target required flow rate, and output control data; the fluid parameter detection sensor monitors the sealant viscosity signal in real time and feeds the signal back to the second controller; the second controller controls the mesh adjuster to adjust the effective pore area of ​​the filter screen to ensure that the flowability of the sealant matches the filling process requirements, avoid insufficient filling or air bubble residue caused by excessively high sealant viscosity, ensure that the sealant forms radial laminar diffusion, and avoid local accumulation caused by turbulence.

[0031] Preferably, such as Figure 1As shown, a positioning and transfer tube 7 is provided on the outer side of the diffusion layer 2. The positioning and transfer tube 7 is connected to an injection pump (not shown). The injection pump (not shown) is used to inject sealant into the device. The sealant output by the injection pump (not shown) is precisely guided to the target gap area through the positioning and transfer tube 7 to avoid the sealant from shifting or splashing.

[0032] On the other hand, the present invention provides a method for sealing the end face of an optical fiber preform, which is produced using the optical fiber preform end face sealing equipment as described in any of the preceding claims, and includes the following steps: Includes the following steps: S1 Insert the end of the fiber preform nested tube (not shown) into the guide tube 1 to a predetermined depth; The S2 axial adjustment and positioning device cooperates with the clamping assembly 3 to position and lock the clamp at the preset sealing position at the end of the fiber preform nested tube (not shown); S3 injects sealant into the equipment, and the sealant flows through the pore structure 5 of the diffusion layer 2. Under the action of the pore structure 5, it forms a radially uniform laminar diffusion state to fill the circumferential gap of the preset sealing position with sealant. After the sealant has cured, release the clamp (not shown) from its locking and clamping position, and remove the diffusion layer 2.

[0033] This invention proposes a method for sealing the end face of an optical fiber preform. The innovative design of the diffusion layer pore structure and the axial adjustment and positioning device not only enables the sealant to diffuse radially and uniformly, which is beneficial to eliminating air bubbles, but also improves the positioning accuracy and gap adjustment accuracy. It automatically compensates for the processing error at the end of the optical fiber preform nested tube, so that the sealant completely and uniformly fills the gap around the nested tube, thereby improving the working efficiency and airtightness.

[0034] Preferably, in step S2, the inner diameter of the guide tube 1 and the outer diameter of the fiber preform nesting tube (not shown) form a clearance fit, with a clearance range of 0.1-1.5 mm. The pore density of the pore structure in step S3 is 50-200 mesh, and the pore distribution uniformity deviation of the pore structure is ≤5%. A gap of 0.1-1.5mm ensures stable laminar flow of the sealant (Reynolds number Re<2000), avoiding local accumulation or bubble defects caused by turbulence; a pore density of 50-200 mesh (corresponding to a pore size of 75-300μm) combined with a uniformity deviation of ≤5% enables precise control of the sealant flow rate (0.5-2.0mL / s), achieving radial uniform diffusion and synergistic control to achieve uniform distribution of the sealant.

[0035] Preferably, the predetermined depth in step S1 is 3-5 mm; In step S3, the injection rate of sealant into the equipment is 0.1-0.5 ml / min, and the injection time is 6-10 min. A 3-5mm depth ensures that the sealant fully fills the gaps (such as the extended area of ​​the 0.1-1.5mm gap between the fiber preform nesting tube and the guide tube), while avoiding excessive accumulation that could lead to stress concentration. A slow booster flow of 0.1-0.5 mL / min can match the curing characteristics of the sealant (condensation type requires 8-24 hours to fully cure), preventing air bubbles or uncured sealant residue, while reducing the time required for a single seal.

[0036] Preferably, the sealant is a UV-curable adhesive or an epoxy adhesive.

[0037] Example 1 like Figure 1-5 As shown, this embodiment provides an optical fiber preform end face sealing device, including: 5 air hole units, each air hole unit comprising: The guide tube 1 is used to accommodate the end of the single-layer optical fiber preform nested tube (not shown) (outer diameter 20.0±0.1mm) and form a sealant flow channel; A diffusion layer 2, sleeved on the outside of the guide tube 1, includes a porous structure 5 that enables the injected sealant to form a radially uniform laminar diffusion. The porous structure 5 includes a filter screen 8 and a mesh adjuster 6 disposed on the filter screen 8. The mesh adjuster 6 includes an adjustment window corresponding to the mesh position of the filter screen. A fluid parameter detection sensor is used to detect the viscosity of the sealant in real time. The fluid parameter detection sensor is electrically connected to a second controller, which is electrically connected to the mesh adjuster. The second controller controls the mesh adjuster to dynamically and automatically adjust the effective pore area of ​​the filter screen according to the sealant viscosity and the required flow rate, adjusting the pore density of the effective pore area to 200 mesh with a pore distribution deviation ≤3%. The fluid parameter detection sensor monitors the sealant viscosity signal in real time and feeds the signal back to the second controller. The second controller controls the mesh adjuster 6 to adjust the effective pore area of ​​the filter screen 8 to ensure that the flowability of the colloid matches the filling process requirements. A clamping assembly 3 is detachably connected to the outside of the diffusion layer 2. The clamping assembly 3 includes a clamp capable of positioning and locking onto the end of the fiber preform nesting tube (not shown). The clamp includes an adjustable clamping part (not shown) for adapting to fiber preform nesting tubes (not shown) of different thicknesses. The adjustable clamping part (not shown) includes: An adjustable clamping gap elastic clamping mechanism (not shown) and a stepped slot (not shown) for multi-specification sleeve adaptation to adapt to fiber optic preform nesting tubes (not shown) with a wall thickness of 2.0 mm. An axial adjustment and positioning device is configured to automatically form a predetermined gap fit between the guide tube 1 and the fiber preform nesting tube (not shown) when the clamp (not shown) reaches a preset sealing position. The predetermined gap fit between the guide tube 1 and the fiber preform nesting tube (not shown) has a gap size of 0.2 mm. The axial adjustment and positioning device includes an axial adjustment mechanism and a positioning detector. The axial adjustment mechanism includes an axial slide rail 4 disposed on the outer circumferential bottom of the clamp; and a drive assembly (not shown) for driving the clamp (not shown) to move along the axial slide rail. (Not shown) Connected to the drive assembly (not shown), the positioning detector is used to detect the preset sealing position at the end of the preformed rod nested tube (not shown) in real time. The positioning detector is electrically connected to the first controller, which is electrically connected to the drive assembly (not shown). The first controller controls the drive assembly (not shown) to drive the clamp (not shown) to move along the axial slide rail 4 and to position and lock the preset sealing position at the end of the preformed rod nested tube (not shown). The clamp includes an adjustable clamping part (not shown), which is used to adapt to fiber optic preformed rod nested tubes of different thicknesses. The diffusion layer 2 is provided with a positioning and transmission tube 7 on its outer side. The positioning and transmission tube 7 is connected to an injection pump (not shown). The injection pump is used to inject sealant into the device. This embodiment provides a method for sealing the end face of an optical fiber preform, which is produced using the optical fiber preform end face sealing equipment described above, and includes the following steps: Includes the following steps: S1 Inserts the end of the fiber preform nested tube (not shown) into the guide tube 1 to a predetermined depth of 4.0 mm; The S2 axial adjustment and positioning device cooperates with the clamping assembly 3 to position and lock the clamp (not shown) at the preset sealing position at the end of the fiber preform nesting tube (not shown); The S3 injection pump injects UV-curable adhesive (viscosity 500 cP) into the device at a rate of 0.2 ml / min for 8 minutes. The sealant flows through the pore structure 5 of the diffusion layer 2 and forms a radially uniform laminar flow (Reynolds number Re < 100) diffusion state under the action of the pore structure 5, so as to fill the circumferential gap of the preset sealing position with sealant. After S4 uses a 365nm ultraviolet lamp to irradiate for 15 minutes to cure the sealant, the locking and clamping of the fixture (not shown) is released, and the diffusion layer 2 is removed; After airtightness testing, the results showed that when the five air vent units were pressurized to 1000 Pa, the pressure could be stabilized and maintained for 30 seconds, indicating good airtightness. Example 2 like Figure 1-5As shown, this embodiment provides an optical fiber preform end face sealing device, including: 5 air hole units, each air hole unit comprising: The flow guide tube 1 is used to accommodate the end of the double-layer optical fiber preform nested tube (not shown) and form a sealant flow channel. The double-layer optical fiber preform nested tube (not shown) includes an inner tube and an outer tube outside the inner tube. The outer diameter of the inner tube is 15 mm, the inner diameter of the outer tube is 16.5 mm, and the gap is 1.5 mm. The flow guide tube 1 is stepped with an inner diameter of 16.8 mm in the upper section (0.3 mm gap between the outer tubes) and 15.3 mm in the lower section (0.3 mm gap between the inner tubes). A diffusion layer 2 is sleeved on the outside of the guide tube 1. The diffusion layer 2 includes a porous structure 5 that enables the injected sealant to form a radially uniform laminar diffusion. The porous structure 5 includes a filter screen 8 and a mesh regulator 6 disposed on the filter screen 8. The mesh regulator 6 includes an adjustment window corresponding to the pore position of the filter screen 8. A fluid parameter detection sensor is used to detect the viscosity of the sealant in real time. The fluid parameter detection sensor is electrically connected to a second controller, which is electrically connected to the mesh regulator 6. The second controller controls the mesh regulator 6 to dynamically and automatically adjust the effective pore area of ​​the filter screen 8 according to the sealant viscosity and the required flow rate. The pore density of the effective pore area is 50 mesh, and the pore distribution deviation is ≤4%. The fluid parameter detection sensor monitors the sealant viscosity signal in real time and feeds the signal back to the second controller. The second controller controls the mesh regulator to adjust the effective pore area of ​​the filter screen to ensure that the flowability of the colloid matches the filling process requirements. A clamping assembly 3 is detachably connected to the outside of the diffusion layer 2. The clamping assembly 3 includes a clamp capable of positioning and locking onto the end of the fiber preform nesting tube (not shown). The clamp includes an adjustable clamping part (not shown) for adapting to fiber preform nesting tubes (not shown) of different thicknesses. The adjustable clamping part (not shown) includes: An adjustable clamping gap elastic clamping mechanism (not shown) and a stepped slot (not shown) for multi-specification sleeve adaptation to adapt to 2.5 mm thick fiber preform nesting tube (not shown). An axial adjustment and positioning device is configured to automatically form a predetermined gap fit between the guide tube 1 and the fiber preform nesting tube (not shown) when the clamp (not shown) reaches a preset sealing position. The predetermined gap fit between the guide tube 1 and the fiber preform nesting tube (not shown) has a gap size of 1.5 mm. The axial adjustment and positioning device includes an axial adjustment mechanism and a positioning detector. The axial adjustment mechanism includes an axial slide rail 4 disposed on the outer circumferential bottom of the clamp (not shown); and a drive assembly for driving the clamp (not shown) to move along the axial slide rail 4. (Not shown) is connected to the drive assembly (not shown). The positioning detector (not shown) is used to detect the preset sealing position at the end of the preformed rod nested tube (not shown) in real time. The positioning detector is electrically connected to the first controller. The first controller is electrically connected to the drive assembly and controls the drive assembly to drive the clamp to move along the axial slide rail 4 and to position and lock the preset sealing position at the end of the preformed rod nested tube (not shown). The clamp (not shown) includes an adjustable clamping part (not shown). The adjustable clamping part (not shown) is used to adapt to fiber optic preformed rod nested tubes (not shown) of different thicknesses. The diffusion layer 2 is provided with a positioning and transmission tube 7 on its outer side. The positioning and transmission tube 7 is connected to an injection pump (not shown). The injection pump (not shown) is used to inject sealant into the device. This embodiment provides a method for sealing the end face of an optical fiber preform, which is produced using the optical fiber preform end face sealing equipment described above, and includes the following steps: Includes the following steps: S1 Simultaneously inserts the end of the double-layer fiber preform nested tube (not shown) into the guide tube 1 to a predetermined depth of 5.0 mm; The S2 axial adjustment and positioning device works in conjunction with the clamping assembly to position and lock the clamp at a preset sealing position at the end of the fiber preform nested tube (not shown); S3: The injection pump (not shown) injects epoxy adhesive in two stages: The injection pump (not shown) injects epoxy adhesive into the equipment in two stages. The first stage (outer tube gap): The injection pump (not shown) injects epoxy adhesive into the equipment at a boosting speed of 0.5 ml / min for 5 min. The second stage (inner tube gap): The injection pump (not shown) injects epoxy adhesive into the equipment at a boosting speed of 0.3 ml / min for 7 min. The sealant flows through the pore structure of the diffusion layer 2. Under the action of the pore structure 5, it forms a radially uniform laminar diffusion state within a 1.5 mm wide gap to fill the circumferential gap of the preset sealing position with sealant. S4 After curing the sealant in an oven at 80℃ for 120 min, release the locking and clamping of the fixture, and remove the diffusion layer to form a double sealing ring; After airtightness testing, the results showed that when 1000 Pa was applied to the 5 air vent units, the pressure could be stabilized and maintained for 30 seconds, indicating good airtightness. It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of this invention.

Claims

1. A fiber optic preform end-face sealing device, characterized in that, include: The guide tube is used to accommodate the end of the fiber optic preform nested tube and form a channel for the flow of sealant. A diffusion layer is sleeved on the outside of the guide tube, and the diffusion layer contains a porous structure that enables the injected sealant to form a radially uniform laminar diffusion. A clamping assembly is detachably connected to the outside of the diffusion layer, the clamping assembly including a clamp capable of positioning and locking to the end of the fiber preform nested tube; The axial adjustment and positioning device is configured to automatically form a predetermined gap fit relationship between the guide tube and the fiber preform nesting tube when the clamp reaches the preset sealing position.

2. The optical fiber preform end face sealing device according to claim 1, characterized in that, The axial adjustment and positioning device includes: an axial adjustment mechanism, the axial adjustment mechanism comprising: An axial slide rail is provided at the bottom of the outer periphery of the clamp; A drive assembly that drives the clamp to move along the axial slide rail.

3. The optical fiber preform end-face sealing device according to claim 1 or 2, characterized in that, The fixture includes an adjustable clamping part, which is used to adapt to fiber optic preform nesting tubes of different thicknesses. The predetermined gap size between the flow guide tube and the fiber preform nesting tube is 0.1-1.5mm.

4. The optical fiber preform end face sealing device according to claim 2, characterized in that, The axial adjustment and positioning device includes: a positioning detector, which is used to detect the preset sealing position at the end of the preformed rod nested tube in real time. The positioning detector is electrically connected to a first controller, which is electrically connected to a drive assembly. The first controller controls the drive assembly to drive the clamp to move along the axial slide rail and to position and lock the preset sealing position at the end of the preformed rod nested tube.

5. The optical fiber preform end-face sealing device according to claim 1, characterized in that, The porous structure includes a filter screen and a mesh size adjuster disposed on the filter screen, the mesh size adjuster including an adjustment window corresponding to the mesh size of the filter screen.

6. The optical fiber preform end-face sealing device according to claim 5, characterized in that, include: A fluid parameter detection sensor is used to detect the viscosity of the sealant in real time. The fluid parameter detection sensor is electrically connected to a second controller, which is electrically connected to the mesh adjuster. The second controller controls the mesh adjuster to dynamically and automatically adjust the effective pore area of ​​the filter screen according to the sealant viscosity and the required flow rate.

7. The optical fiber preform end-face sealing device according to claim 1, characterized in that, A positioning and transmission tube is provided on the outer side of the diffusion layer. The positioning and transmission tube is connected to an injection pump, which is used to inject sealant into the device.

8. A method for sealing the end face of an optical fiber preform, characterized in that, The production process using the optical fiber preform end-face sealing equipment as described in any one of claims 1-7 includes the following steps: S1 Inserts the end of the fiber preform nested tube into the guide tube to a predetermined depth; The S2 axial adjustment and positioning device works in conjunction with the clamping assembly to position and lock the clamp at the preset sealing position at the end of the fiber preform nested tube. S3 injects sealant into the equipment, and the sealant flows through the pore structure of the diffusion layer, forming a radially uniform laminar diffusion state under the action of the pore structure, so as to fill the circumferential gap of the preset sealing position with sealant. After the sealant has cured, release the clamps and remove the diffusion layer.

9. The optical fiber preform end face sealing method according to claim 8, characterized in that, In step S2, the inner diameter of the guide tube and the outer diameter of the fiber preform nested tube form a clearance fit, with a clearance range of 0.1-0.2 mm. The pore density of the pore structure in step S3 is 50-200 mesh, and the pore distribution uniformity deviation of the pore structure is ≤5%.

10. The optical fiber preform end face sealing method according to claim 9, characterized in that, The predetermined depth mentioned in step S1 is 3-5 mm; In step S3, the injection rate of sealant into the equipment is 0.1-0.5 ml / min, and the injection time is 6-10 min.

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