A method for using a large-diameter long cooling tube for optical fiber drawing

Abstract

This invention provides a method for using a large-diameter long cooling tube for optical fiber drawing. The large-diameter long cooling tube includes multiple cooling tube bodies, each with a cooling tube end-face shutter connected to both ends. Each shutter includes a shutter body, a first radial channel, an end-face connection portion, and a second radial channel. Before production at the fiber drawing tower, the two cooling tube end-face shutters are opened, the inner walls of the cooling tubes are cleaned, and production resumes. After closing the two cooling tube end-face shutters, cooling helium is introduced into the first radial channel of one cooling tube end-face shutter, and a protective gas is introduced into the first radial channel of the other sealed cooling tube end-face shutter for sealing. This invention reduces the processing and installation precision of the cooling tube; by providing helium recovery ports at both shutters, a negative pressure is created to improve leakage at the end face of the large-diameter cooling tube; a gas seal is provided at the shutter, and the positive pressure created by introducing the protective gas reduces helium overflow from the cooling tube, saving helium and improving helium recovery efficiency.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber production, and specifically relates to a method for using a large-diameter long cooling tube for optical fiber drawing. Background Technology

[0002] Optical fiber production involves melting preforms at high temperatures in an optical fiber drawing furnace, drawing them into fibers, and then processing them through multiple steps such as cooling, coating, and curing to create optical fibers. Optical fiber cooling is completed within cooling tubes. The working principle involves a refrigerator cooling the cooling tubes, and the introduction of rare helium gas into the tubes as a heat exchange medium to cool the optical fiber.

[0003] The rising price of helium, constrained by supply constraints, has increased the manufacturing cost of optical fibers. To reduce helium consumption, the industry typically manufactures cooling tubes with small-aperture structures, with an inner diameter of approximately 5-8 mm, and an open / closed design to address the requirements of cooling tube wall cleaning and fiber feeding during production. However, to meet length-direction accuracy requirements, small-aperture cooling tubes are usually structurally complex, expensive, and difficult to install, extend, or modify. Furthermore, this structure demands high sealing standards, requiring seamless connections between sections, and helium leakage along the long dimension cannot be completely eliminated. Summary of the Invention

[0004] The purpose of this invention is to provide a method for using a large-diameter long cooling tube for optical fiber drawing that can not only reduce the processing and installation accuracy of the cooling tube but also effectively solve the helium leakage problem.

[0005] This invention is implemented as follows: A large-diameter long cooling tube for optical fiber drawing is characterized by comprising multiple cooling tube bodies connected sequentially to form a long cooling tube. A cooling water channel is provided on the long cooling tube, and an insulation layer is provided on its outer periphery. Cooling tube end-face shutters are connected to both ends of the long cooling tube. The cooling tube end-face shutters are variable-diameter structures, comprising a shutter body, a small-diameter optical fiber channel body communicating with the long cooling tube, a first radial channel, and an end-face connection portion for connecting to one end of the long cooling tube. The inner end of the shutter body extends into the long cooling tube by a predetermined distance. A second radial channel is provided on the end-face connection portion. The first radial channel of one cooling tube end-face shutter is connected to the cooling tube helium inlet, and the second radial channel is connected to the recovered helium outlet. The first radial channel of another cooling tube end-face shutter is connected to the cooling tube gas seal inlet, and the second radial channel is connected to the recovered helium outlet.

[0006] In some alternative implementations, an extension section is provided between the end face connection and the shutter body, and an annular space is provided between the extension section and the outer diameter of the small-diameter fiber optic channel tube, with the second radial channel installed at the extension section.

[0007] In some alternative implementations, adjacent cooling tubes are sealed together via end-face flanges.

[0008] In some alternative implementations, a sealing groove for installing a seal is provided on the end face of the cooling tube.

[0009] In some alternative implementations, multiple axial cooling water channels are provided on the cooling pipe body, and the axial cooling water channels on adjacent cooling pipes are connected.

[0010] In some alternative implementations, the inner diameter of the long cooling tube is greater than 30 mm.

[0011] In some alternative implementations, the inner end of the shutter body extends 50-150 mm into a long cooling pipe.

[0012] In some alternative implementations, an inert gas is introduced into the gas seal inlet of the cooling pipe.

[0013] In some alternative implementations, the inner diameter of the small-diameter fiber channel tube is 5-8 mm.

[0014] A method for using a large-diameter long cooling tube for optical fiber drawing as described above, characterized by comprising the following steps: Before production begins in the drawing tower, the shutters at the ends of the two cooling tubes are opened, and the inner walls of the cooling tubes are cleaned before production resumes. After closing the shutters, cooling helium is introduced into the first radial channel of one shutter, and protective gas is introduced into the first radial channel of the other shutter to seal it. The positive pressure created by the protective gas reduces helium leakage from the cooling tubes. Helium recovery is then connected to the second radial channels of both shutters to create negative pressure and improve leakage at the ends of the large-diameter cooling tubes. During operation, low-temperature cooling water is introduced into the inner walls of the cooling tubes for heat exchange.

[0015] The beneficial effects of this invention are: 1. This invention uses a large-diameter cooling pipe, with shutters of 5mm inner diameter at both ends of the cooling pipe outlet for sealing. These shutters can be removed when the machine is stopped, reducing the processing and installation precision required for the cooling pipe. By providing helium recovery ports at both shutters, a negative pressure is created to improve leakage at the end face of the large-diameter cooling pipe. A gas seal is provided at the shutter, and the positive pressure created by introducing protective gas reduces the overflow of helium in the cooling pipe, saving helium and improving helium recovery efficiency. 2. By installing the second radial channel (helium recovery port) at the extension section, that is, the exhaust port of the helium recovery port is located inside the cooling pipe, the exhaust position avoids the optical fiber channel, reducing optical fiber jitter and further improving the exhaust efficiency. 3. Small-diameter shutters are provided at the upper and lower openings of the cooling pipe to effectively avoid helium leakage. The upper and lower shutters use the same structure, which is used for gas inlet, helium recovery and gas sealing respectively, making it highly versatile.

[0016] 4. The long cooling pipes are connected in a joint manner, and the outer wall is wrapped with insulation material. Low-temperature water is used for cooling, which can avoid condensation problems. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a large-diameter long cooling tube structure for optical fiber drawing, provided as an embodiment of the present invention.

[0019] Figure 2 This is a shutter cross-sectional view of the cooling pipe end face provided in an embodiment of the present invention.

[0020] Figure 3 This is a schematic cross-sectional view of the cooling pipe body provided in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0029] like Figure 1 As shown, this embodiment provides a large-diameter long cooling tube for optical fiber drawing, including multiple cooling tube bodies 5. Cooling water channels 11 are provided on the cooling tube bodies 5. Adjacent cooling tube bodies are connected in sequence to form a long cooling tube. A heat insulation layer 4 is provided on the outer periphery of the long cooling tube, and cooling tube end face shutters (1, 10) are respectively connected to its two ends.

[0030] like Figure 2 As shown, the cooling tube end-face shutter is a variable-diameter structure, comprising a shutter body 101. The shutter body 101 has a small-diameter fiber optic channel tube 102 communicating with a long cooling tube, a first radial channel 2, and an end-face connection portion 104 for connecting to one end of the long cooling tube. The inner end of the shutter body extends into the long cooling tube by a predetermined distance. An extension section 103 is provided between the end-face connection portion 104 and the shutter body 101. An annular space 105 is provided between the extension section 103 and the outer diameter of the small-diameter fiber optic channel tube. A second radial channel is provided at the extension section, and the second radial channel communicates with the annular space. The first radial channel 2 of one cooling tube end-face shutter 1 connects to the helium inlet of the cooling tube, and the second radial channel 3 connects to the helium recovery outlet. The first radial channel 9 of the other cooling tube end-face shutter connects to the gas seal inlet of the cooling tube, and the second radial channel 8 connects to the helium recovery outlet.

[0031] In this embodiment, the long cooling tube is 9-10m long and has an inner diameter greater than 30mm. A shutter with an inner diameter of 5mm is installed at the outlets at both ends of the long cooling tube for sealing the cooling tube; this shutter can be removed when the machine is stopped. That is, the inner diameter of the small-diameter fiber optic channel tube with the shutter at the cooling tube end face is 5mm. Adjacent cooling tubes are freely spliced ​​and extended through end-face flange sealing connections to achieve better cooling effects. Sealing grooves for installing seals are provided on the end faces of the cooling tubes, allowing adjacent cooling tubes to be sealed together and preventing the leakage of cooling water and helium. The cooling tube is a seamless steel tube with a jacketed cooling water channel, which not only cools the fiber optic cable but also effectively solves the helium leakage problem. Specifically, as shown... Figure 3 As shown, multiple axial cooling water channels 5 are provided on the cooling pipe body, and the axial cooling water channels on adjacent cooling pipes are connected. An interface for connecting to the cooling water pump is provided on the cooling pipe body (omitted in the figure).

[0032] This embodiment also provides a method for using the above-mentioned large-diameter long cooling tube for optical fiber drawing, which specifically includes the following steps: Before production begins in the drawing tower, the two cooling tube end face shutters (1, 10) are opened, the inner walls of the cooling tubes are cleaned, and production resumes. After closing the two cooling tube end face shutters (1, 10), cooling helium is introduced into the first radial channel 2 of the cooling tube end face shutter 1, and a protective gas (inert gas) is introduced into the first radial channel 9 of the sealed cooling tube end face shutter 10 for sealing. The positive pressure created by the protective gas reduces helium leakage from the cooling tubes. Helium recovery is connected to the second radial channels (3, 8) of the two cooling tube end face shutters to create a negative pressure, improving leakage at the end faces of large-diameter cooling tubes. During operation, low-temperature cooling water is introduced into the inner walls of the cooling tubes for heat exchange. Throughout the production process, helium leakage and overflow are minimal. The additional helium recovery device enables efficient cooling of the cooling tubes.

[0033] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for using a large-diameter long cooling tube for optical fiber drawing, characterized in that: A large-diameter long cooling tube for optical fiber drawing comprises multiple cooling tube bodies with cooling water channels on each body. Adjacent cooling tube bodies are connected sequentially to form a long cooling tube. An insulation layer is provided around the outer periphery of the long cooling tube. Cooling tube end-face shutters are connected to both ends of the long cooling tube. The cooling tube end-face shutters are variable-diameter structures, including a shutter body, a small-diameter optical fiber channel body communicating with the long cooling tube, a first radial channel, and an end-face connection portion for connecting to one end of the long cooling tube. The inner end of the shutter body extends into the long cooling tube by a predetermined distance. A second radial channel is provided on the end-face connection portion, wherein one cooling tube... The first radial channel of the shutter on the end face of the cooling tube is connected to the helium inlet of the cooling tube, and the second radial channel is connected to the helium recovery outlet; the first radial channel of the shutter on the other end face of the cooling tube is connected to the gas seal inlet of the cooling tube, and the second radial channel is connected to the helium recovery outlet; an extension section is provided between the end face connection and the shutter body, and an annular space is provided between the extension section and the outer diameter of the small-diameter fiber optic channel tube, and the second radial channel is installed at the extension section; the second radial channel serves as the exhaust port of the helium recovery port, and it is connected to the annular space to form a negative pressure channel, and the inner end of the shutter body extends into the long cooling tube by 50-150mm; Before production begins, the shutters at the ends of the two cooling tubes are opened, and the inner walls of the cooling tubes are cleaned before production resumes. After closing the shutters at the ends of the two cooling tubes, cooling helium is introduced into the first radial channel of one cooling tube end-face shutter, and protective gas is introduced into the first radial channel of the other sealed cooling tube end-face shutter for sealing. The positive pressure created by the protective gas reduces the leakage of helium from the cooling tubes. Helium is recovered by connecting it to the second radial channels of the two cooling tube end-face shutters, creating a negative pressure to improve leakage at the ends of the large-diameter cooling tubes. During operation, low-temperature cooling water is introduced into the inner wall of the cooling tubes for heat exchange.

2. The method of use according to claim 1, characterized in that, Adjacent cooling pipes are sealed together by end face flanges.

3. The method of use according to claim 2, characterized in that, A sealing groove for installing seals is provided on the end face of the cooling pipe.

4. The method of use according to claim 1, characterized in that, Multiple axial cooling water channels are provided on the cooling pipe body, and the axial cooling water channels on adjacent cooling pipes are connected.

5. The method of use according to claim 1, characterized in that, The inner diameter of the long cooling pipe is greater than 30 mm.

6. The method of use according to claim 1, characterized in that, Inert gas is introduced into the gas seal inlet of the cooling pipe.

7. The method of use according to claim 1, characterized in that, The inner diameter of the small-diameter fiber optic channel tube is 5-8 mm.

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