A method and apparatus for controlling the corrosion of a preform to a target outside diameter

Abstract

The application provides a method and a device for controlling the corrosion of a preform rod to a target outer diameter, and belongs to the technical field of special optical fiber manufacturing. The initial outer diameter and length of the preform rod are measured, the outer diameter of the preform rod after corrosion is determined, the outer diameter difference of the preform rod after corrosion is determined, the volume change is calculated, the tension change is calculated, the value on the tension meter at the corrosion end point is determined, the value on the tension meter gradually decreases from the initial value during the corrosion process, the corrosion process is terminated when the value is the value on the tension meter at the corrosion end point, and the outer diameter of the preform rod is the target outer diameter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of special optical fiber manufacturing, and particularly relates to a method and device for controlling the corrosion of a preform rod to a target outer diameter. BACKGROUND

[0002] In the manufacturing process of optical fibers, hydrofluoric acid is used to corrode and clean the optical fiber preform rod, which has two purposes: one is to remove the impurities and defect layer on the surface of the optical fiber preform rod, so that the subsequently drawn optical fiber has lower optical transmission loss and longer service life; the other is to corrode the preform rod to a certain size to meet the diameter ratio of the core and the cladding, or to reduce the outer diameter of the preform rod so that it can be inserted into a sleeve tube for subsequent collapsing or drawing. As can be seen, it is very important for the optical fiber manufacturing to efficiently and accurately corrode the preform rod to the target outer diameter.

[0003] Currently, in the optical fiber manufacturing industry, there are generally two methods for corroding and cleaning the optical fiber preform rod with hydrofluoric acid: one is through a horizontal acid washing tank, the preform rod is placed horizontally in the horizontal acid washing tank together with an extension rod, the hydrofluoric acid liquid surface is above the preform rod, and the preform rod is corroded and cleaned; the other is to use a vertical acid washing tank, the acid washing tank is filled with hydrofluoric acid, the preform rod has an extension rod at one end, the extension rod is fixed on a clamp or an upper end support, and the preform rod is vertically immersed in the hydrofluoric acid liquid, and the preform rod is corroded and cleaned by the hydrofluoric acid.

[0004] Generally speaking, the horizontal acid washing tank has a relatively large volume and a relatively complex structure, and is suitable for optical fiber preform rods with a relatively large outer diameter and a relatively large volume, while the vertical acid washing tank has a simple structure and a relatively small volume, and can be used for optical fiber preform rods with a relatively small outer diameter, so the vertical acid washing tank is widely used in the special fiber industry.

[0005] Chinese patent document CN219342023U discloses a preform rod clamping piece and a preform rod acid washing device, which comprises a supporting part and a clamping part, the supporting part is used to be arranged at the opening of the acid washing cylinder, and the clamping part is movably arranged on the supporting part and at least partially extends into the clamping space formed between the clamping part and the side wall of the clamping space. The preform rod clamping piece and the preform rod acid washing device provided by the utility model have the advantages of simple operation, fastening and cleaning of preform rods of different sizes, reduction of the number of times of contacting acid liquid by the operator, improvement of acid washing efficiency, and guarantee of personal safety. However, the focus of the patent is on the clamping of the preform rod, and the preform rod cannot be accurately corroded to the target outer diameter while ensuring that the preform rod will not fall. SUMMARY

[0006] In view of the above defects of the prior art, the technical problem to be solved by the present application is to provide a method and a device for controlling the corrosion of a preform to a target outer diameter by accurately measuring the tension change of the preform before and after corrosion.

[0007] In order to achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0008] A method for controlling the corrosion of a preform to a target outer diameter, comprising the following steps:

[0009] S1 accurately measuring the length L of the preform;

[0010] S2 measuring the outer diameter D0 of the preform before corrosion by taking the average value of multiple points;

[0011] S3 presetting the target outer diameter D1 of the preform after corrosion as required;

[0012] S4 calculating the volume change V of the preform before and after corrosion;

[0013] S5 measuring the tension value F0 of the preform before corrosion by using a digital tension meter;

[0014] S6 calculating the actual weight loss G1 of the preform;

[0015] S7 calculating the value F1 of the reduced buoyancy of the preform;

[0016] S8 when the tension value F measured by the digital tension meter is F 终 =F0-(G1-F1), the corrosion is completed.

[0017] Preferably, the calculation formula of V is V=(π / 4)×(D0×D0-D1×D1)×L.

[0018] Preferably, the calculation formula of G1 is G1=(π / 4)×(D0×D0-D1×D1)×L×2.28×9.8 / 1000.

[0019] Preferably, the calculation formula of F1 is F1=(π / 4)×(D0×D0-D1×D1)×L×1.19×9.8 / 1000.

[0020] Preferably, the calculation formula of F 终 =F0-(G1-F1)=F0-(π / 4)×(D0×D0-D1×D1)×L×1.09×9.8 / 1000. 终

[0021] ​The present application determines the outer diameter difference of the preform rod to be corroded by measuring the D0 and L of the preform rod, measuring the pulling force value F0 of the preform rod before corrosion by using the digital tension meter, and calculating the actual weight reduction G1 of the preform rod and the value F1 of the reduction of the buoyancy of the preform rod according to the above formula, and the final pulling force value F measured by the digital tension meter at the corrosion end point is F 终 =F0-(G1-F1), the value on the digital tension meter gradually decreases from the initial F0 during the corrosion process, and the corrosion is completed when the pulling force value F measured by the digital tension meter is F 终 =F 终 =F0-(G1-F1), and the outer diameter of the preform rod at this time is the target outer diameter.

[0022] The present application also discloses a device for calculating the corrosion of the preform rod to the target outer diameter by using the above method, which comprises a vertical tank body, a corrosive solution, a preform rod, an extension rod, a clamp, a hook and a digital tension meter.

[0023] Preferably, the device further comprises an end cap, and the end cap is provided with a hole through which the preform rod passes, and the size of the end cap corresponds to the caliber of the upper segment of the vertical tank body.

[0024] Compared with the prior art, the present application has the beneficial effects that:

[0025] 1. The preform rod is not frequently taken out from the vertical pickling tank for cleaning and the outer diameter of the preform rod is not measured by using a vernier caliper during the corrosion process, so that the production efficiency is higher.

[0026] 2. Since the main component of the solution used for cleaning the corroded preform rod is hydrofluoric acid, which is very harmful to the human body, the above method can reduce the contact between personnel and hydrofluoric acid, and the manufacturing process is safer.

[0027] 3. The newly configured hydrofluoric acid has a high concentration and a fast corrosion speed for the preform rod, and the corrosion speed of the preform rod decreases with the decrease of the concentration of the hydrofluoric acid, and the present method can accurately control the corrosion amount regardless of the change of the concentration of the hydrofluoric acid.

[0028] 4. The present method can monitor the real-time pulling force change of the preform rod on line, so as to inversely deduce the outer diameter change of the preform rod, and realize more accurate control of the outer diameter of the final preform rod. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a plan view of the preform rod corrosion and cleaning device of the present application.

[0030] Wherein 1, tank body; 2, corrosive solution; 3, preform rod; 4, extension rod; 5, end cap; 6, preform rod fixing clamp; 7, preform rod hook; 8, digital tension meter. DETAILED DESCRIPTION

[0031] Example 1

[0032] A method for controlling the corrosion of a preform rod to a target outer diameter, comprising the following steps:

[0033] S1 accurately measure the length of the preform rod 100 cm;

[0034] S2 multiple point measurement to get the average value of the outer diameter of the preform rod before corrosion 2 cm;

[0035] S3 pre-set the target outer diameter of the preform rod after corrosion is 1.8 cm;

[0036] S4 calculate the outer diameter change of the preform rod before and after corrosion is 0.2 cm, and further calculate the volume change is 59.66 cm 3 ;

[0037] S5 use digital tension meter to measure the tension value of the preform rod before corrosion 15.0 N;

[0038] S6 calculate the actual weight loss of the preform rod is 1.286 N;

[0039] S7 calculate the value of the buoyancy reduction of the preform rod 0.677 N;

[0040] S8 when the tension value measured by the digital tension meter is 14.391 N, the corrosion is completed.

[0041] As Figure 1 shown in a device for controlling the corrosion of a preform rod to a target outer diameter using the above method, comprising a vertical tank body 1, a corrosive solution 2, a preform rod 3, an extension rod 4, a clamp 6, a hook 7 and a digital tension meter 8; the corrosive solution 2 is contained in the vertical tank body 1; the preform rod 3 is immersed in the corrosive solution 2, the top end is connected with the extension rod 4, the upper end of the extension rod 4 is clamped by the clamp 6, the hook 7 is arranged between the clamp 6 and the digital tension meter 8, and the corrosive solution is hydrofluoric acid.

[0042] As a preferred embodiment of the present application, the device further comprises an end cap 5; the end cap is provided with a hole for the preform rod to pass through; the size of the end cap 5 corresponds to the upper end of the vertical tank body 1 in one-to-one correspondence. On the one hand, the end cap can be passed through by the preform rod, and on the other hand, the tank can be sealed, reducing the volatilization of hydrofluoric acid and reducing the harm to the human body.

[0043] The method for using the device is as follows: firstly, the extension rod 4 connected with the prefabricated rod 3 is fixed on the clamp 6, the hydrogen fluoride solution is filled in the stereoscopic groove 1, the up and down positions of the prefabricated rod 3 are adjusted, the whole prefabricated rod 4 is immersed in the hydrogen fluoride solution, the extension rod 4 is outside the hydrogen fluoride solution, and then according to the control method, the corrosion process is terminated when the display value of the corrosion end point of the digital tension gauge 8 is the target value.

Claims

1. A method of controlling the corrosion of a preform to a target outside diameter, characterized by, It comprises the following steps: S1 precisely measuring the length L of the preform; S2 taking the average value of the outer diameter D0 of the preform before corrosion by multi-point measurement; S3 presetting the target outer diameter D1 of the preform after corrosion; S4 calculating the volume change V of the preform before and after corrosion; S5 measuring the pulling force value F0 of the preform before corrosion by using a digital pull force meter; S6 calculating the actual reduced gravity value G1 of the preform; S7 calculating the reduced value F1 of the buoyancy of the preform; S8 when the tensile force value measured by the digital tension meter is F 终 =F0-(G1-F1) when corrosion is completed.

2. The method of controlling the corrosion of a preform to a target outside diameter of claim 1, wherein: The calculation formula of V is V=(π / 4)×(D0×D0-D1×D1)×L.

3. The method of controlling the corrosion of a preform to a target outside diameter of claim 1, wherein: The calculation formula of G1 is G1=(π / 4)×(D0×D0-D1×D1)×L×2.28×9.8 / 1000.

4. The method of controlling the corrosion of a preform to a target outside diameter of claim 1, wherein: The calculation formula of F1 is F1=(π / 4)×(D0×D0-D1×D1)×L×1.19×9.8 / 1000.

5. The method for controlling the corrosion of the preform to the target outer diameter according to claim 1, characterized in that: The F 终 The calculation formula is F 终 =F0-(G1-F1)=F0-(π / 4)×(D0×D0-D1×D1)×L×1.09×9.8 / 1000.

6. A device for use in a method of controlling the corrosion of a preform rod to a target outer diameter as claimed in any one of claims 1 to 5, characterised in that: It comprises a vertical tank body, a corrosive solution, a preform, an extension rod, a clamp, a hook and a digital pull force meter; the corrosive solution is contained in the vertical tank body; one end of the preform is immersed in the corrosive solution, and the other end is connected with the extension rod; the upper end of the extension rod is clamped by the clamp; the hook is arranged between the clamp and the digital pull force meter.

7. The apparatus of claim 6, wherein: The device further comprises an end cover; the end cover is provided with a hole through which the preform passes; the size of the end cover corresponds to the caliber of the upper segment of the vertical tank body.

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