阅读说明：本技术 控制生产过程中光纤预制棒疏松体密度的系统及方法 (System and method for controlling density of loose body of optical fiber preform rod in production process ) 是由 吴志元 郑伟 章海峰 张学军 王强强 于 2021-09-17 设计创作，主要内容包括：本发明涉及光纤生产技术领域,具体涉及一种控制生产过程中光纤预制棒疏松体密度的系统及方法,包括监测系统,用于监测光纤预制棒疏松体的直径和重量,并将监测数据进行实时反馈；控制系统,用于接收所述监测数据,并以此计算得到光纤预制棒疏松体的密度,经与设定密度曲线比对进一步得到密度误差后,发送配方调整指令；MFC,用于执行所述控制系统下发的配方调整指令,控制喷灯调整相关气体流量,进而实现光纤预制棒疏松体密度的调整。本发明减少了疏松体的开裂,减少了疏松体烧结后包层出现各种不良情况,增加光纤的强度等,提高了产品的合格率。(The invention relates to the technical field of optical fiber production, in particular to a system and a method for controlling the density of a loose body of an optical fiber preform rod in a production process, wherein the system comprises a monitoring system, a feedback system and a feedback system, wherein the monitoring system is used for monitoring the diameter and the weight of the loose body of the optical fiber preform rod and feeding back monitoring data in real time; the control system is used for receiving the monitoring data, calculating to obtain the density of the loose body of the optical fiber preform, comparing the density with a set density curve to further obtain a density error, and then sending a formula adjustment instruction; and the MFC is used for executing the formula adjustment instruction issued by the control system and controlling the blowtorch to adjust the flow of the related gas so as to realize the adjustment of the density of the loose body of the optical fiber preform. The invention reduces the cracking of the loose body, reduces various adverse conditions of the cladding after the loose body is sintered, increases the strength of the optical fiber and the like, and improves the qualification rate of products.)

1. A system for controlling the density of a loose body of an optical fiber preform during production, comprising

The monitoring system is used for monitoring the diameter and the weight of the loose body of the optical fiber perform rod and feeding back the monitoring data in real time;

the control system is used for receiving the monitoring data, calculating to obtain the density of the loose body of the optical fiber preform, comparing the density with a set density curve to further obtain a density error, and then sending a formula adjustment instruction;

and the MFC is used for executing the formula adjustment instruction issued by the control system and controlling the blowtorch to adjust the flow of the related gas so as to realize the adjustment of the density of the loose body of the optical fiber preform.

2. The system for controlling the density of a loose body of an optical fiber preform during production according to claim 1, wherein the monitoring system comprises a laser caliper and a weighing device; the laser diameter measuring instrument is used for monitoring the diameter of the loose body of the optical fiber perform rod, and the weighing device is used for monitoring the weight of the loose body of the optical fiber perform rod in real time.

3. The system for controlling the density of a bulk body of an optical fiber preform during a production process according to claim 2, wherein the laser diameter measuring instrument is used for measuring the diameter of the bulk body of the optical fiber preform, and feeding back the distance from the diameter measuring instrument to the surface of the bulk body of the optical fiber preform to the control system, and the control system calculates the volume of the bulk body of the optical fiber preform according to the distance,

wherein, the volume calculation formula is as follows:

r + h1-h 2; wherein r is the radius of the core rod; h1 is the distance from the initial laser diameter gauge to the mandrel;

h2 distance from laser diameter measurer to loose body of prefabricated optical fiber rod;

v-2/3 pi R2h + pi R2L-pi R2(L +2 h); wherein h is the length of the cone, L is the length of the core rod, R is the diameter of the loose body of the optical fiber preform rod, and R is the diameter of the core rod.

4. The system for controlling the density of a soot body of an optical fiber preform during a production process of claim 3, wherein the laser caliper measures the distance of the soot body of the optical fiber preform every X rounds of the operation of the torch, wherein X is a positive integer.

5. The system of claim 2, wherein the weighing device returns to zero after the mandrel is mounted while monitoring the weight of the loose body of the optical fiber preform in real time, the weighing device is used for weighing the net weight of the single-side deposit and feeding the net weight back to the control system, and the actual weight G of the rod is obtained by multiplying the weight of the single-side deposit by (2+ error value).

6. The system for controlling the density of a bulk body of an optical fiber preform during the production process as claimed in claim 1, wherein the control system calculates the density of the bulk body of the optical fiber preform using the following equation: and p is G/V, wherein G is the weight V of the loose body of the optical fiber preform and the volume of the loose body of the optical fiber preform.

7. The system for controlling the density of a loose body of an optical fiber preform during the production process as claimed in claim 1, wherein the density error is ± 0.02g/cm³When this error value is exceeded, the control system sends a recipe adjustment command.

8. The system of claim 1, wherein the gas CH is adjusted when the burner adjusts the flow rate of the gas concerned₄And set O₂And CH₄Proportion of (A) to (B), O₂According to the ratio with CH₄Become variableIn which CH₄Adjustment value/CH₄And (4) after the flow is changed, depositing X rounds, and judging whether to change again according to the result.

9. The system for controlling the bulk density of an optical fiber preform during the manufacturing process of claim 1, wherein the working environment of the monitoring system is provided with a CDA cooling gas.

10. A method for controlling the density of a loose body of an optical fiber preform during production, which is performed by the system for controlling the density of a loose body of an optical fiber preform during production according to any one of claims 1 to 9, comprising the steps of:

s1, acquiring diameter and weight data of the loose body of the optical fiber preform;

s2, calculating the density of the loose body of the optical fiber preform through the data in S1, and comparing the density with a set density curve;

and S3, judging whether the error value range is exceeded, and adjusting the flow of the related gas to realize the adjustment of the density of the loose body of the optical fiber preform.

Technical Field

The invention relates to the technical field of optical fiber production, in particular to a system and a method for controlling the density of a loose body of an optical fiber preform rod in a production process.

Background

The OVD deposition process is the main process for producing the overcladding layer of the optical fiber preform rod, and according to statistics, the optical fiber manufactured by adopting the OVD overcladding process accounts for more than six times of the total output of the optical fibers in the world, and the mechanism of the OVD is flame hydrolysis, namely gaseous halide (SiCl)₄Etc.) react with oxyhydrogen flame or methane flame to generate large dust which moves back and forth along the rod body along with the burner holder, and the dust is gradually deposited on the outer surface of the core rod layer by layer to finally form a cylindrical preform loose body.

The density of the loose body is an important parameter for controlling an OVD deposition process, the uneven density of the loose body can cause the cracking of a rod body in the production process, and various defects appear on a cladding after sintering.

In the chinese invention patent No. CN201810852202.7, a method for manufacturing an optical fiber preform is disclosed, comprising the steps of: in the OVD deposition process, periodically scanning the outer diameter of the loose body and calculating the fluctuation of the outer diameter of the loose body, and adjusting a corresponding blast lamp when the fluctuation of the outer diameter is larger than a preset range; after the deposition is finished, scanning the outer diameter of the loose body, and calculating a first descending speed and a second descending speed; and vitrifying the loose bodies, wherein the loose bodies are descended at a first descending speed within a preset distance from the maximum outer diameter position, and the loose bodies are descended at a second descending speed within a preset distance from the minimum outer diameter position.

The density is ensured to be as uniform as possible by adjusting the flow of the blowtorch corresponding to the maximum outer diameter or the minimum outer diameter. In the existing equipment and process, after the cladding deposition is finished, the overall average density of the loose body is tested, the condition of the sintered rod body is observed, and then rough formula adjustment is carried out.

However, the prior art has no method for controlling the uniformity of the density of the rod body, the result feedback is delayed, and the density cannot be found in time and the formula cannot be changed in time; formula adjustment may require multiple adjustments to achieve an ideal effect; formulation adjustments do not allow for finding the exact time point. Accordingly, a system and method for controlling the density of a loose body of an optical fiber preform during production is provided.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discloses a system and a method for controlling the loose body density of an optical fiber preform rod in the production process, which are used for solving the problems.

The invention is realized by the following technical scheme:

in a first aspect, the present invention provides a system for controlling the bulk density of an optical fiber preform during production, comprising

The monitoring system is used for monitoring the diameter and the weight of the loose body of the optical fiber perform rod and feeding back the monitoring data in real time;

the control system is used for receiving the monitoring data, calculating to obtain the density of the loose body of the optical fiber preform, comparing the density with a set density curve to further obtain a density error, and then sending a formula adjustment instruction;

and the MFC is used for executing the formula adjustment instruction issued by the control system and controlling the blowtorch to adjust the flow of the related gas so as to realize the adjustment of the density of the loose body of the optical fiber preform.

Furthermore, the monitoring system comprises a laser diameter measuring instrument and a weighing device; the laser diameter measuring instrument is used for monitoring the diameter of the loose body of the optical fiber perform rod, and the weighing device is used for monitoring the weight of the loose body of the optical fiber perform rod in real time.

Further, the weighing device and the laser caliper need to be cooled by CDA cooling gas to prevent sensor abnormality due to excessive temperature.

Furthermore, the control system calculates the density of the loose body, compares the density with a set density curve, and adjusts the formula according to the density error.

Furthermore, when the diameter of the loose body of the optical fiber preform rod is monitored by the laser diameter measuring instrument, the distance from the diameter measuring instrument to the surface of the loose body of the optical fiber preform rod is firstly measured and fed back to the control system, the control system calculates the volume of the loose body of the optical fiber preform rod according to the distance,

wherein, the volume calculation formula is as follows:

r + h1-h 2; wherein r is the radius of the core rod; h1 is the distance from the initial laser diameter gauge to the mandrel; h2 distance from laser diameter measurer to loose body of prefabricated optical fiber rod;

v-2/3 pi R2h + pi R2L-pi R2(L +2 h); wherein h is the length of the cone, L is the length of the core rod, R is the diameter of the loose body of the optical fiber preform rod, and R is the diameter of the core rod.

Furthermore, the density of the loose body is measured by the blast lamp every X times, and X is not too small or too large, and is controlled to be 5-10 generally.

Further, when the diameter of the loose body of the optical fiber preform is monitored by the laser diameter measuring instrument, the distance is measured once every X rounds of operation of the blast burner, wherein X is a positive integer.

Furthermore, when the weighing device monitors the weight of the loose body of the optical fiber preform rod in real time, after the mandrel is installed, the weighing device returns to zero, the weighing device weighs the net weight of the single-side deposition and feeds the net weight back to the control system, and the actual weight G of the rod body is obtained by multiplying the weight of the single-side deposition by the (2+ error value).

Further, the control system calculates the density of the loose body of the optical fiber preform by using the following formula: and p is G/V, wherein G is the weight V of the loose body of the optical fiber preform and the volume of the loose body of the optical fiber preform.

Further, the density error is + -0.02 g/cm³When this error value is exceeded, the control system sends a recipe adjustment command.

Furthermore, the control system compares the calculated density with the density curve of the set loose body, and the error exceeds +/-0.02 g/cm³Need to adjust CH₄Of which CH₄Adjustment value/CH₄And (4) an initial set value is a density error value/density set value coefficient, after the flow is changed, the X rounds are deposited, and the adjustment is carried out again according to the situation.

Further, when the burner adjusts the flow rate of the relevant gas, the flow rate of the gas CH4 is adjusted, and O is set₂And CH₄Proportion of (A) to (B), O₂According to the ratio with CH₄In which CH is present₄After each change, whether the change is carried out again is judged according to the result.

Furthermore, the working environment of the monitoring system is provided with CDA cooling gas.

In a second aspect, the present invention provides a method for controlling the density of a loose body of an optical fiber preform during production, the method being implemented in the system for controlling the density of a loose body of an optical fiber preform during production according to the first aspect, comprising the steps of:

s1, acquiring diameter and weight data of the loose body of the optical fiber preform;

s2, calculating the density of the loose body of the optical fiber preform through the data in S1, and comparing the density with a set density curve;

and S3, judging whether the error value range is exceeded, and adjusting the flow of the related gas to realize the adjustment of the density of the loose body of the optical fiber preform.

The invention has the beneficial effects that:

the control system of the invention calculates the density of the loose bodies through the data fed back by the laser diameter measuring instrument and the weighing device, compares the density with the set density curve, and adjusts the formula according to the error, so that the density distribution of each loose body reaches the set state, the cracking of the loose bodies is reduced, various adverse conditions of the cladding after the loose bodies are sintered are reduced, the strength of the optical fiber is increased, and the like, and the qualification rate of the product is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a system for controlling the bulk density of a preform of optical fiber during production;

FIG. 2 is a diagram of a method for controlling the density of a loose body of an optical fiber preform during production;

FIG. 3 is a graph of the density of the loose objects versus the number of passes over a torch platform according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to FIG. 1, the present embodiment provides a system for controlling the density of a loose body of an optical fiber preform during production, comprising

The monitoring system is used for monitoring the diameter and the weight of the loose body 5 of the optical fiber perform rod and feeding back the monitoring data in real time;

the control system 2 is used for receiving the monitoring data, calculating the density of the loose body 5 of the optical fiber preform rod according to the monitoring data, comparing the density with a set density curve to further obtain a density error, and then sending a formula adjustment instruction;

and the MFC3 is used for executing the formula adjustment instruction issued by the control system 2 and controlling the blowtorch to adjust the flow rate of the relevant gas, so as to adjust the density of the loose body 5 of the optical fiber preform.

The monitoring system of the embodiment comprises a laser diameter measuring instrument 1 and a weighing device 4; wherein the laser diameter measuring instrument 1 is used for monitoring the diameter of the loose body 5 of the optical fiber perform rod, and the weighing device 4 is used for monitoring the weight of the loose body 5 of the optical fiber perform rod in real time.

The control system 2 of the embodiment needs to adjust CH according to the calculated density and the error of the density curve of the set loose body exceeding +/-0.02 g/cm3₄Of which CH₄Adjustment value/CH₄And (4) changing the flow rate, depositing X rounds, and adjusting again according to the situation.

The method can improve the yield of OVD deposition, reduce the defects of the rod body and simultaneously reduce the problems of rod body cracking or serious defects caused by the error of manually changing the formula.

Example 2

In a specific implementation aspect, this embodiment provides a specific implementation of a system for controlling the density of a loose body of an optical fiber preform during a production process, and the system first calculates the density of the loose body according to the system, compares the density with a set density curve, and adjusts a formula according to the density error.

In this embodiment, what laser diameter measuring instrument 1 tested is the distance from the laser diameter measuring instrument to the measured object, and the radius of the loose body is calculated according to the distance:

r is R + h1-h2, wherein R is the radius of the mandrel, h1 is the distance from the initial laser diameter measuring instrument to the mandrel, and h2 is the distance from the laser diameter measuring instrument to the loose body during testing.

In this embodiment, if R is 15mm, h1 is 500mm, and h2 is 470mm, the radius of the loose body is calculated as R, where R is 17+500 and 470 is 45 mm.

Calculating the volume of the loose body according to the radius of the loose body:

v-2/3 tr 2h + tr 2L-tr 2(L +2h) where h is the length of the taper, L is the length of the mandrel, R is the diameter of the loose body, and R is the diameter of the mandrel.

In this example, h is 150mm, L is 1700mm, R is 50mm, and R is 15mm

V＝2/3*3.14*50^2*150+3.14*50^2*1700-3.14*15^2*(1700+300)

＝12717000mm³

＝12717cm³

Density calculation formula: where G is the weight of the bulk and V is the volume of the bulk.

The density of the loose body is measured by the blowtorch for every X rounds of operation, wherein X is not too small or too large, and is controlled to be 5-10 generally. As shown in FIG. 3, ρ represents the density of the loose mass and A represents the number of passes the torch platform has made. The error of the middle control system 2 is more than +/-0.02 g/cm according to the calculated density and compared with the density curve of the set loose body³Need to adjust CH₄Flow of (CH)₄Adjustment value/CH₄Initial set value as density error valueThe/density set value coefficient, after the flow rate is changed, is deposited with X rounds and is adjusted again according to the situation.

The invention can improve the qualification rate of OVD deposition, reduce the defects of the rod body and also reduce the cracking or serious defects of the rod body caused by the error of manually changing the formula.

Example 3

This example provides an optimum deposition condition, i.e. when the deposition is completed in 100 passes, the volume V of the bulk is 19500cm³Wherein the weight G of the loose body is 12500G, and the density rho is 0.641G/cm³The set value is 0.6g/cm³Deviation of 0.041g/cm³Adjusting CH₄After the flow rate, the density became 0.605g/cm³And meets the requirements.

Example 4

As shown in fig. 2, the present embodiment provides a method for controlling the loose bulk density of an optical fiber preform during production, comprising the steps of:

s1, acquiring diameter and weight data of the loose body of the optical fiber preform;

s2, calculating the density of the loose body of the optical fiber preform through the data in S1, and comparing the density with a set density curve;

and S3, judging whether the error value range is exceeded, and adjusting the flow of the related gas to realize the adjustment of the density of the loose body of the optical fiber preform.

In conclusion, the control system of the invention calculates the density of the loose bodies through the data fed back by the laser diameter measuring instrument and the weighing device, compares the density with the set density curve, and adjusts the formula according to the error, so that the density distribution of each loose body reaches the set state, the cracking of the loose bodies is reduced, various adverse conditions of the cladding after the loose bodies are sintered are reduced, the strength of the optical fiber is increased, and the like, and the qualification rate of the product is improved.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.