A drawing preparation system for thin-diameter bend-resistant optical fiber

Abstract

The present invention discloses a drawing preparation system for thin-diameter bend-resistant optical fibers, comprising a heating furnace; a plurality of graphite parts disposed within the heating furnace; an upper graphite furnace sealed chamber disposed at the upper portion of the heating furnace; and a lower graphite furnace sealed chamber disposed at the lower portion of the heating furnace; a preform rod being connected to a drive assembly; an optical fiber position measuring instrument disposed at the exit of the lower graphite furnace sealed chamber; and a drying gas chamber, a bare optical fiber diameter gauge, a coating die, a coated optical fiber diameter gauge, a first UV curing lamp, and a second UV curing lamp disposed sequentially below the optical fiber position measuring instrument; an optical fiber drawn from the second UV curing lamp being sequentially passed through a bottom wheel, a first traction wheel, a tension wheel, and a second traction wheel, and wound around a take-up drum, wherein a tension sensor is mounted on the tension wheel. The present invention has an optical fiber strength test function, which can detect optical fiber strength problems during the drawing process, thereby improving optical fiber production quality and efficiency and reducing optical fiber production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber preparation, and in particular relates to a drawing preparation system for thin-diameter bend-resistant optical fibers. Background Art

[0002] Compared with wireless transmission via ordinary copper cables, optical fiber transmission has the advantages of high bandwidth, low loss, light weight, and strong anti-interference ability. The basic principle of optical fiber transmission is to utilize the total reflection of light. The total reflection of light requires that the optical fiber cannot have small radius bends, because the bending of the optical fiber will destroy the total reflection condition. However, in actual use and applications, small radius bends must be performed. At the same time, with the development of integrated technology, the requirements for miniaturization of equipment are getting higher and higher. Therefore, the development of optical fibers with smaller size and excellent performance is the future development direction.

[0003] The optical fibers produced by the current mainstream optical fiber drawing equipment all have a cladding diameter of 125um and a coating diameter of 245um. If this drawing equipment is directly used to draw small-diameter bend-resistant optical fibers, the optical and geometric parameters of the optical fibers cannot be guaranteed to be qualified, and the production yield is low.

[0004] Furthermore, many fiber drawing furnaces now use argon gas and induction heating. While argon is inexpensive and induction furnaces are fast, the quality of the bare fiber fluctuates significantly, failing to meet the requirements of specialty optical fibers. Furthermore, during the drawing process, the fiber's strength cannot be verified. This is only done after the drawing process, using a fiber rewinder. If the strength is poor, the entire reel is discarded. This compromises quality and efficiency, resulting in significant waste. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and provide a drawing and preparation system for thin-diameter bend-resistant optical fibers, so as to solve the problems of low production efficiency and poor quality of the existing thin-diameter optical fibers.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A drawing preparation system for thin-diameter bend-resistant optical fibers comprises a heating furnace; a plurality of graphite parts are arranged in the heating furnace; an upper graphite furnace sealed cavity for sealing the heating furnace and preform rods is arranged at the upper portion of the heating furnace; and a lower graphite furnace sealed cavity is arranged at the lower portion of the heating furnace; the top of the preform rod is connected to a drive assembly, which drives the preform rod to move vertically downward in the heating furnace; an optical fiber position measuring instrument is arranged at the outlet of the lower sealed cavity of the graphite furnace; a drying gas cavity, a bare optical fiber diameter gauge, a coating die, a coated optical fiber diameter gauge, a first UV curing lamp, and a second UV curing lamp are arranged in sequence below the optical fiber position measuring instrument; the optical fiber guided from the second UV curing lamp passes through a bottom wheel, a first traction wheel, a tension wheel, and a second traction wheel in sequence and is wound around a take-up drum, and a tension sensor is installed on the tension wheel.

[0008] Furthermore, a first helium inlet is provided on one side of the upper sealed cavity of the graphite furnace.

[0009] Furthermore, a Y-shaped barrel is provided in the sealed cavity at the lower part of the graphite furnace, the upper end of the Y-shaped barrel is connected to the heating furnace, and a baffle is installed at the outlet of the lower end of the Y-shaped barrel.

[0010] Furthermore, a second helium inlet is provided at the upper end of the dry gas chamber, and a dry gas inlet is provided at the lower end thereof; a cooling tube is provided in the dry gas chamber and distributed along the periphery of the optical fiber, a coolant inlet on the cooling tube is provided at the lower part of the dry gas chamber, and a coolant outlet on the cooling tube is provided at the upper part of the dry gas chamber.

[0011] Furthermore, the coating mold is connected to the first coating layer paint tank and the second coating layer paint tank through the first coating layer paint supply pipe and the second coating layer paint supply pipe respectively; the first coating layer paint tank is connected to the first coating layer compressed air supply, and the second coating layer paint tank is connected to the second coating layer compressed air supply.

[0012] Furthermore, control valves are installed on both the first coating layer paint supply pipe and the second coating layer paint supply pipe; and liquid level sensors are installed in both the first coating layer paint tank and the second coating layer paint tank.

[0013] Furthermore, the drive assembly includes a feed servo motor, a feed chuck and a precision screw; the feed servo motor is installed on a support frame, and one end of the precision screw is connected to the output shaft of the feed servo motor through a coupling; the free end of the precision screw passes through the support arm of the feed chuck and is rotationally connected to the base plate of the support frame.

[0014] Furthermore, the precision screw is threadedly connected to the support arm of the feeding chuck, and the feeding chuck is fixed to the support frame through the support arm.

[0015] Furthermore, the driving assembly drives the preform rod to move at a speed of:

[0016] V p=×ω

[0017]

[0018] Among them, V p is the moving speed of the preform rod; P is the pitch of the precision screw; ω is the angular velocity of the precision screw; D f is the diameter of the bare optical fiber; Vs is the speed of the traction wheel; D1 is the diameter of the preform rod; M1 is the mass of the glass in the preform rod; M f is the total mass of the bare fiber; l is the total length of the bare fiber; ρ is the density of the bare fiber; K is the proportional coefficient, unit is s -1 ; τ is the time; D2 is the predetermined value of the optical fiber diameter; D t is the measured value of the optical fiber diameter at time t.

[0019] The drawing and preparation system for thin-diameter bend-resistant optical fibers provided by the present invention has the following beneficial effects:

[0020] The present invention controls the downward movement speed of the preform rod by cooperating with a feeding servo motor and a precision lead screw to ensure the diameter of the bare optical fiber; the present invention also has an optical fiber strength inspection function, which can detect optical fiber strength problems during the drawing process, improve the quality and efficiency of optical fiber production, and reduce the cost of optical fiber production; and the present invention is compatible with optical fibers with a cladding diameter of 80-125um and a coating diameter of 100-245um, and the cladding fluctuation is less than 0.3um. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural block diagram of the drawing preparation system for thin-diameter bend-resistant optical fibers.

[0022] in:

[0023] 1. Preform; 2. Feed servo motor; 3. Feed chuck; 4. Precision screw; 5. Heating furnace; 6. Upper sealed chamber of graphite furnace; 7. First helium inlet; 8. Lower sealed chamber of graphite furnace; 9. Baffle; 10. Fiber position measuring instrument; 11. Cooling tube; 12. Second helium inlet; 13. Coolant outlet; 14. Coolant inlet; 15. Drying gas chamber; 16. Drying gas inlet; 17. Bare fiber diameter gauge; 18. Preform laser diameter gauge.

[0024] 19. Coating die; 1911. First coating layer paint supply pipe; 1912. First coating layer compressed air supply; 1913. First coating layer paint tank; 1921. Second coating layer paint supply pipe; 1922. Second coating layer compressed air supply; 1923. Second coating layer paint tank;

[0025] 20. Coated optical fiber diameter gauge; 21. First UV curing lamp; 22. Second UV curing lamp; 23. Bottom wheel; 24. First traction wheel; 25. Tension wheel; 26. Second traction wheel; 27. Take-up drum. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0027] Example 1

[0028] This embodiment provides a drawing and preparation system for thin-diameter bend-resistant optical fibers. This embodiment can prepare thin-diameter bend-resistant optical fibers that meet the requirements and has an optical fiber strength inspection function. Compared with the existing technology, it can improve the quality and efficiency of optical fiber production and reduce the cost of optical fiber production. Figure 1 , which specifically include:

[0029] A heating furnace 5, wherein a plurality of graphite parts are provided in the heating furnace 5, an upper graphite furnace sealed cavity 6 for sealing the heating furnace 5 and the preform 1 is provided at the upper portion of the heating furnace 5, and a lower graphite furnace sealed cavity 8 is provided at the lower portion of the heating furnace 5;

[0030] A preform laser diameter measuring instrument 18 is provided in the heating furnace 5 for collecting the current diameter of the preform in real time.

[0031] Specifically, a first helium inlet 7 is provided on one side of the upper sealed chamber 6 of the graphite furnace; a Y-shaped barrel is provided in the lower sealed chamber 8 of the graphite furnace, the upper end of the Y-shaped barrel is connected to the heating furnace 5, and a baffle 9 is installed at the lower end outlet of the Y-shaped barrel;

[0032] In this embodiment, the heating furnace 5 needs to melt the preform rod 1 at a high temperature of 2000 degrees. There are a large number of graphite parts inside the heating furnace 5. Helium needs to be introduced from the helium inlet to ensure that the graphite parts are not oxidized. The sealed cavity 6 at the upper part of the graphite furnace can continuously keep the preform rod 1 warm and stabilize the gas flow rate. The Y-shaped barrel provided in the sealed cavity 8 at the lower part of the graphite furnace can smooth the airflow. The smooth airflow can effectively suppress the fluctuation of the bare optical fiber, and the baffle 9 can effectively block the influx of external oxygen.

[0033] The top of the preform rod 1 is connected to the driving assembly, which drives the preform rod 1 to move vertically downward in the heating furnace 5. The downward movement speed of the preform rod 1 will directly affect the diameter of the bare optical fiber. Therefore, this embodiment uses the driving assembly to control the downward movement speed of the preform rod 1 in real time.

[0034] Specifically, the driving assembly includes a feeding servo motor 2, a feeding chuck 3 and a precision screw 4; the feeding servo motor 2 is installed on the support frame, and one end of the precision screw 4 is connected to the output shaft of the feeding servo motor 2 through a coupling; the free end of the precision screw 4 passes through the support arm of the feeding chuck 3 and is rotationally connected to the base plate of the support frame; the precision screw 4 is threadedly connected to the support arm of the feeding chuck 3, and the feeding chuck 3 is fixed to the support frame through the support arm.

[0035] The calculated moving speed of the driving assembly driving the preform 1 is:

[0036] V p =P×ω (1)

[0037]

[0038] Among them, V p is the moving speed of the preform rod 1; P is the pitch of the precision screw 4; ω is the rotational angular velocity of the precision screw 4; D f is the diameter of the bare optical fiber; Vs is the speed of the traction wheel; D1 is the diameter of the preform 1; M1 is the mass of the glass in the preform 1; M f is the total mass of the bare fiber; l is the total length of the bare fiber; ρ is the density of the bare fiber; K is the proportional coefficient, unit is s -1 ; τ is the time; D2 is the predetermined value of the optical fiber diameter; D t is the measured value of the optical fiber diameter at time t, which can be directly obtained through the measurement data of the bare optical fiber diameter gauge 17 at time t;

[0039] Formula (2) of this embodiment can be based on the current real-time measurement value D of the optical fiber diameter at time t t , adjust the current preform rod 1 downward speed in real time, after obtaining the current preform rod 1 downward speed, and then obtain the preform rod 1 moving speed V p Substitute into formula (1) and solve in reverse to obtain the rotational angular velocity ω of the precision screw 4. After obtaining the rotational angular velocity ω of the precision screw 4, the output power of the feeding servo motor 2 is adjusted in real time according to the rotational angular velocity ω. In order to improve the accuracy of the bare optical fiber diameter, this embodiment selects a feeding servo motor 2 that can be controlled with high precision, and installs an encoder on the rotating shaft of the feeding servo motor 2 to obtain the rotational angular velocity ω of the precision screw 4 in real time, so as to avoid the error between the actual rotation speed of the feeding servo motor 2 and the theoretical rotation speed.

[0040] An optical fiber position measuring instrument 10 is provided at the outlet of the sealed cavity 8 at the lower part of the graphite furnace. The optical fiber position measuring instrument 10 can detect the position of the optical fiber in the heating furnace 5, ensure that the optical fiber is in the center position in the heating furnace 5, and effectively improve the geometric accuracy of the optical fiber.

[0041] Located below the optical fiber position measuring instrument 10 are a drying gas chamber 15, a bare optical fiber diameter gauge 17, a coating mold 19, a coated optical fiber diameter gauge 20, a first UV curing lamp 21 and a second UV curing lamp 22. The optical fiber derived from the second UV curing lamp 22 is sequentially passed around the bottom wheel 23, the first traction wheel 24, the tension wheel 25, the second traction wheel 26 and wound around the take-up drum 27. A tension sensor is installed on the tension wheel 25.

[0042] The drying gas chamber 15 has a second helium inlet 12 at its upper end and a drying gas inlet 16 at its lower end. Cooling tubes 11 are disposed within the drying gas chamber 15 and extend along the periphery of the optical fiber. A coolant inlet 14 is disposed on the cooling tubes 11 at the lower portion of the drying gas chamber 15 , and a coolant outlet 13 is disposed on the cooling tubes 11 at the upper portion of the drying gas chamber 15 .

[0043] Specifically, dry gas is filled into the dry gas chamber 15 through the dry gas inlet 16, reducing the dew point inside the dry gas chamber 15 to below -40°C. Coolant is introduced into the cooling tube 11 through the coolant inlet 14, and the coolant flows out through the coolant outlet 13. High-purity helium with a helium content greater than or equal to 99.9% is introduced into the second helium inlet 12. The high-purity helium is conducive to transferring heat from the optical fiber to the cooling tube 11, and then the heat is taken away by the coolant, thereby reducing the temperature of the optical fiber.

[0044] In this embodiment, the coating mold 19 is connected to the first coating layer paint tank 1913 and the second coating layer paint tank 1923 through the first coating layer paint supply pipe 1911 and the second coating layer paint supply pipe 1921 respectively; the first coating layer paint tank 1913 is connected to the first coating layer compressed air supply 1912, and the second coating layer paint tank 1923 is connected to the second coating layer compressed air supply 1922.

[0045] Control valves are installed on the first coating layer paint supply pipe 1911 and the second coating layer paint supply pipe 1921; liquid level sensors are installed in the first coating layer paint tank 1913 and the second coating layer paint tank 1923.

[0046] This embodiment uses a wet-on-wet coating mold 19, and compressed air is introduced into the first coating layer paint tank 1913 through the first coating layer compressed air supply 1912, and the paint is pressed into the coating mold 19 through the first coating layer paint supply pipe 1911. Compressed air is introduced into the second coating layer paint tank 1923 through the second coating layer compressed air supply 1922, and the paint is pressed into the coating mold 19 through the second coating layer paint supply pipe 1921, and the optical fiber is coated with resin through the mold.

[0047] This embodiment is provided with two independently operating first coating layer paint tanks 1913 and second coating layer paint tanks 1923. Under the control of the control valve, the two paint tanks can be fed simultaneously or separately. In one case, when the paint in one paint tank is about to be exhausted (or reaches a critical value), the other paint tank is promptly controlled to feed, which can avoid the problem of shutting down the entire equipment when changing materials. That is, the two paint tanks are used in coordination to meet high-power paint operations (two paint tanks operate at the same time), and can also be used alternately for continuous operations that are not simple. Compared with the existing technology, it greatly improves production efficiency and operability.

[0048] The first UV curing lamp 21 and the second UV curing lamp 22 of this embodiment cure the liquid resin into a solid state. A tension sensor is mounted on the bearing of the tension wheel 25 to measure the tension of the optical fiber in real time.

[0049] The second pulley 26 rotates slightly faster than the first pulley 24, creating tension in the optical fiber between the first and second pulleys 24, 26. A tension sensor on the tension pulley 25 measures the fiber tension in real time and adjusts the rotation speed of the second pulley 26 to maintain a constant tension. If a defective optical fiber breaks between the first and second pulleys 24, 26 due to insufficient tension, the equipment issues an alarm, allowing operators to address the problem promptly.

[0050] The present invention controls the downward movement speed of the preform rod 1 by cooperating with the feeding servo motor 2 and the precision lead screw 4 to ensure the diameter of the bare optical fiber; and the present invention has the function of optical fiber strength testing, which can detect optical fiber strength problems during the drawing process, improve the quality and efficiency of optical fiber production, and reduce the cost of optical fiber production.

[0051] Although the specific embodiments of the invention are described in detail in conjunction with the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Within the scope described by the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A drawing system for thin-diameter, bend-resistant optical fibers, characterized by: The heating furnace comprises a heating furnace; a plurality of graphite parts are provided in the heating furnace; an upper graphite furnace sealed cavity for sealing the heating furnace and preform rods is provided at the upper portion of the heating furnace; and a lower graphite furnace sealed cavity is provided at the lower portion of the heating furnace; the top of the preform rod is connected to a drive assembly, and the drive assembly drives the preform rod to move vertically downward in the heating furnace; an optical fiber position measuring instrument is provided at the outlet of the lower sealed cavity of the graphite furnace; and a drying gas chamber, a bare optical fiber diameter gauge, a coating die, a coated optical fiber diameter gauge, a first UV curing lamp, and a second UV curing lamp are provided in sequence below the optical fiber position measuring instrument; the optical fiber guided from the second UV curing lamp passes through a bottom wheel, a first traction wheel, a tension wheel, and a second traction wheel in sequence and is wound around a take-up drum; a tension sensor is installed on the tension wheel; The drive assembly includes a feed servo motor, a feed chuck and a precision screw; the feed servo motor is mounted on a support frame, one end of the precision screw is connected to the output shaft of the feed servo motor via a coupling; the free end of the precision screw passes through the support arm of the feed chuck and is rotatably connected to the bottom plate of the support frame; The precision screw is threadedly connected to the support arm of the feeding chuck, and the feeding chuck is fixed to the support frame through the support arm; The driving assembly drives the preform rod to move at a speed of: （1） （2） in, is the moving speed of the preform; is the pitch on the precision screw; is the angular velocity of the precision screw; D f is the diameter of the bare optical fiber; Vs is the traction wheel speed; D 1 is the preform diameter; M 1 is the mass of glass in the preform; M f is the total mass of the bare optical fiber; is the total length of the bare optical fiber; ρ is the bare fiber density; K is the proportional coefficient, unit is s -1 ; τ For the moment; D 2 is the predetermined value of the optical fiber diameter; D t is the measured value of the optical fiber diameter at time t; Based on the current real-time measurement value Dt of the optical fiber diameter at time t, the current preform rod downward speed is adjusted in real time. After the current preform rod downward speed is obtained, the obtained preform rod moving speed is adjusted. Substitute into equation (1) and solve the reverse equation to get the angular velocity of the precision screw: , after obtaining the angular velocity of the precision screw Then, according to the rotation angular velocity , adjust the output power of the feeding servo motor in real time; in order to improve the accuracy of the bare optical fiber diameter, a feeding servo motor that can be controlled with high precision is selected, and an encoder is installed on the rotating shaft of the feeding servo motor to obtain the rotational angular velocity of the precision screw in real time to avoid the error between the actual rotation speed of the feeding servo motor and the theoretical rotation speed.

2. The drawing system for thin-diameter bend-resistant optical fiber according to claim 1, characterized in that: A first helium inlet is provided on one side of the upper sealed cavity of the graphite furnace.

3. The drawing system for thin-diameter bend-resistant optical fiber according to claim 1, characterized in that: A Y-shaped barrel is provided in the sealed cavity at the lower part of the graphite furnace. The upper end of the Y-shaped barrel is connected to the heating furnace, and a baffle is installed at the outlet of the lower end of the Y-shaped barrel.

4. The drawing system for thin-diameter bend-resistant optical fiber according to claim 1, characterized in that: A second helium inlet is provided at the upper end of the dry gas chamber, and a dry gas inlet is provided at the lower end thereof; a cooling tube is provided in the dry gas chamber and distributed along the periphery of the optical fiber, a coolant inlet on the cooling tube is provided at the lower part of the dry gas chamber, and a coolant outlet on the cooling tube is provided at the upper part of the dry gas chamber.

5. The drawing system for thin-diameter bend-resistant optical fiber according to claim 1, characterized in that: The coating die is connected to the first coating layer paint tank and the second coating layer paint tank through the first coating layer paint supply pipe and the second coating layer paint supply pipe respectively; the first coating layer paint tank is connected to the first coating layer compressed air supply, and the second coating layer paint tank is connected to the second coating layer compressed air supply.

6. The drawing system for thin-diameter bend-resistant optical fiber according to claim 5, characterized in that: The first coating layer paint supply pipe and the second coating layer paint supply pipe are both installed with control valves; the first coating layer paint tank and the second coating layer paint tank are both installed with liquid level sensors.

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