CN212335018U - VAD deposited optical fiber perform loose body density on-line detection device - Google Patents
VAD deposited optical fiber perform loose body density on-line detection device Download PDFInfo
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- CN212335018U CN212335018U CN202020886938.9U CN202020886938U CN212335018U CN 212335018 U CN212335018 U CN 212335018U CN 202020886938 U CN202020886938 U CN 202020886938U CN 212335018 U CN212335018 U CN 212335018U
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Abstract
The utility model discloses a VAD deposited optical fiber perform loose body density on-line detection device, which comprises a frame, a weighing mechanism, a laser diameter measuring system, a controller and a deposition cavity, wherein a seed rod is arranged in the deposition cavity; the weighing mechanism comprises a connecting piece, one end of the connecting piece is connected with a seed rod, the upper end of the seed rod is provided with a tension sensor, and the other end of the connecting piece is connected with the rack; the tension sensor and the laser diameter measuring system are connected with the controller, and in the deposition process, the weighing is carried out in real time, and the volume of the loose body is measured in real time, so that the problem that the average density is larger than the real value due to the large density of the cone part of the loose body can be completely avoided, the monitoring of the product condition is realized, and the improvement of the product quality is facilitated.
Description
Technical Field
The utility model relates to a VAD optical fiber perform makes technical field, concretely relates to online detection controlling means of the loose body density of VAD optical fiber perform.
Background
VAD process, one of the main processes for manufacturing a core rod of an optical fiber preform by an outside tube method, is based on the principle that Si02 and Ge02 powders produced by flame hydrolysis reaction are deposited on the end face of a rotating target rod. In the process, the loose body obtained by deposition is slowly lifted upwards, and finally the length of the loose body reaches a set value. Then, the loose powder is converted into a transparent glass body at the temperature of about 1500 ℃ through a sintering process.
The density of the deposited loose body is an important index of the preform and can have an important influence on the subsequent sintering process. Therefore, the measurement and control of the density of the loose body become important links in the production process of the preform.
The traditional measuring method of the preform loose body comprises the following steps: and (4) performing diameter scanning on the loose body after the deposition is finished from top to bottom to obtain the size and the shape of the loose body, and calculating the volume of the loose body. And the weight thereof was obtained by weighing. Finally, the average density of the bulk was obtained. The method can only calculate the average density of the whole loose body, cannot calculate the densities of different axial positions of the loose body, cannot calculate the deposition density of a certain time period in the deposition process, and further cannot realize product control in the production process.
The patent publication No. 209689666U proposes a device for detecting the density of a loose body: and transferring the loose body after deposition to a fixed detection position, obtaining weight information of the loose body through a weighing sensor, scanning the external dimension of the loose body through a laser diameter measuring instrument to obtain diameter information and volume of the loose body, and finally calculating the average density of the loose body.
The above devices have several disadvantages: 1. the loose body needs to be transported to a specified detection position, and the whole transportation process may damage the loose body; 2. the measurement and calculation mode can only obtain the average density of the loose body, and the head cone and the tail cone with higher density can influence the measurement result, so that the measurement result is not completely accurate. 3. Since the density of the deposited compact is measured, the measured density of the compact cannot be adjusted and remedied even if the measurement result is found to be out of the expected value of the process.
Disclosure of Invention
In order to overcome the defects of the prior art, the utility model provides an online detection device for the density of the loose body of the VAD optical fiber perform.
In order to achieve the above purpose, the utility model adopts the technical scheme that:
an online detection device for the density of a loose body of a VAD optical fiber preform comprises a frame, a weighing mechanism, a laser diameter measuring system, a controller and a deposition cavity, wherein a seed rod is arranged in the deposition cavity;
the weighing mechanism comprises a connecting piece, one end of the connecting piece is connected with the seed rod, a tension sensor is arranged at the upper end of the seed rod, the seed rod is weighed and measured through the tension sensor, and the other end of the connecting piece is connected with the rack; the tension sensor and the laser diameter measuring system are connected with the controller.
Furthermore, the connecting piece is a clamp body and is connected with the rack through a rod lifting mechanism, and the rod lifting mechanism can vertically lift along the rack. In order to avoid swinging during movement and ensure the stability during movement, the connecting piece is in hard connection, so the clamp body is adopted.
The laser diameter measuring system can vertically lift and comprises a lifting platform, a laser transmitter and a laser receiver, wherein the laser transmitter and the laser receiver are respectively arranged on the lifting platform at two sides of the deposition cavity.
The deposition chamber is used for depositing the seed rod of the loose body, and two deposition torches are arranged in the deposition chamber and are respectively used for depositing the core layer and the cladding layer.
And the laser diameter measuring system is used for measuring the diameter of the loose body and sending the measured value to the controller.
The laser diameter measuring system can vertically lift and comprises a lifting platform, a laser transmitter and a laser receiver, wherein the laser transmitter and the laser receiver are respectively arranged on the lifting platform at two sides of the deposition cavity;
the deposition cavity is used for the loose body, and glass windows are respectively arranged on two sides of the deposition cavity, so that the diameter of the loose body can be conveniently scanned by a laser transmitter and a receiver.
And a deposition material feeding device is arranged in the deposition cavity and is connected with the controller.
The rod lifting mechanism is a ball screw device and comprises a screw rod and a ball nut, the screw rod is vertically arranged on the rack, the upper end of the screw rod is connected with a servo motor and rotates, the ball screw converts the rotation of the motor into the up-and-down linear motion of the ball nut, and the ball nut drives the loosening body to move through the clamp.
The laser diameter measuring system is arranged on the lifting platform, a lifting driving mechanism of the laser diameter measuring system is the same as the rod lifting mechanism, and a ball screw device is adopted to convert the rotary motion of a motor into the up-and-down linear motion of the lifting platform.
The deposition material feeding device is a deposition blowtorch, the front end of the deposition blowtorch is provided with a mass flow controller for controlling each gas raw material, and the mass flow controller is connected with the controller, so that the flow of the deposition blowtorch can be accurately controlled in real time; the controller adopts Mitsubishi FX2N-128MT type PLC, can process the acquired data in real time, and realizes the adjustment of the flow of the mass flow controller according to the calculation result of the density of the loose body.
An online detection control method for density of a loose body comprises the steps of carrying out real-time weight measurement on the loose body in a deposition cavity through a weighing mechanism, carrying out real-time diameter measurement on the loose body through a laser diameter measurement system, uploading the measured value to a controller, obtaining real-time data in the deposition process of the loose body, and comparing the real-time data with an average density set value of a standard loose body to obtain a monitoring result;
and the controller adjusts the flow of the deposition material feeding device in the deposition cavity according to the comparison result, so as to correct the average density of the loose body in the deposition process.
And the laser diameter measuring system moves up and down in the deposition process to continuously measure the diameter of the whole loose body. The measurement process can be from top to bottom or from bottom to top. Taking the top-down as an example, when the diameter of the loose body measured by the laser diameter measuring system is 110% -130% of the diameter of the seed rod, the measured value is recorded. And then measuring and recording the diameter at intervals of 0.1-5 mm until the diameter is measured to be 0, and finishing sampling. The whole process obtains a set of data d of the diameter of the loose body1,d2，d3....dn。
And the controller is used for receiving the data provided by the weighing system and the laser diameter measuring system and calculating the volume and the density.
The calculation of the bulk volume V is:
The calculation principle and formula of the density are as follows:
during the deposition process, the controller calculates the volume V at the current moment0And recording the weight information M provided by the weighing system at the current moment0. And after T minutes, the diameter measurement is carried out again by the laser diameter measuring system, and the weighing system samples again when the diameter measurement is finished. The controller obtains the volume V after T minutes1And weight information M1Then the average density ρ of the loose deposit in this time T can be determined. The calculation formula is as follows:
in order to ensure the accuracy of measurement, the time interval T between two measurements is not easy to be too small; the T is not easy to be too large for controlling the density of the product. T is preferably 5 to 30.
And the control system is used for controlling the gas flow of the blowtorch according to the calculated loose body density value. When density isLess than 2.2g/cm3The hydrogen flow rate of the cladding layer deposition burner is increased by 0.3-1.5L/min, and the hydrogen flow rate of the core layer deposition burner is increased by 0.1-0.3L/min. When the density is more than 2.5g/cm3The hydrogen flow rate of the cladding layer deposition burner is reduced by 0.3-1.5L/min, and the hydrogen flow rate of the core layer deposition burner is reduced by 0.1-0.3L/min.
In the VAD deposition process, the loose body is continuously lengthened along the axial direction, and the density value calculated through two times of measurement is the average density value on the newly increased length of the loose body.
The utility model has the advantages that:
1. in the deposition process, the loose body volume is measured in real time by weighing in real time, so that the problem that the average density is larger than the true value due to the large cone density can be completely avoided;
2. density detection is carried out in the deposition process, the loose body does not need to be carried in the whole process, and the damage to the loose body in the carrying process is avoided;
3. the loose body grows along the axial direction in the deposition process, so that the measurement of the average density of the loose body at different axial positions can be realized by monitoring through the controller, and the monitoring of the product condition is realized;
4. in the deposition process, the flow of the blast lamp can be adjusted, and the production quality is improved.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
In the figure, 1-a tension sensor, 2-a clamp body, 3-a seed rod, 4-a loose body, 5-a laser emitter, 6-a laser receiver, 7-a lifting table, 8-a cladding deposition burner, 9-a core layer deposition burner, 10-a ball nut, 11-a lead screw and 12-a rack.
Detailed Description
An online detection device for the density of a loose body of a VAD optical fiber preform comprises a frame, a weighing mechanism, a laser diameter measuring system, a controller and a deposition cavity, wherein a seed rod is arranged in the deposition cavity;
the weighing mechanism comprises a connecting piece, one end of the connecting piece is connected with the seed rod, a tension sensor is arranged at the upper end of the seed rod, the seed rod is weighed and measured through the tension sensor, and the other end of the connecting piece is connected with the rack; the tension sensor and the laser diameter measuring system are connected with the controller.
Furthermore, the connecting piece is a clamp body and is connected with the rack through a rod lifting mechanism, and the rod lifting mechanism can vertically lift along the rack. In order to avoid swinging during movement and ensure the stability during movement, the connecting piece is in hard connection, so the clamp body is adopted.
The laser diameter measuring system can vertically lift and comprises a lifting platform, a laser transmitter and a laser receiver, wherein the laser transmitter and the laser receiver are respectively arranged on the lifting platform at two sides of the deposition cavity.
The deposition chamber is used for depositing the seed rod of the loose body, and two deposition torches are arranged in the deposition chamber and are respectively used for depositing the core layer and the cladding layer.
And the laser diameter measuring system is used for measuring the diameter of the loose body and sending the measured value to the controller.
The laser diameter measuring system can vertically lift and comprises a lifting platform, a laser transmitter and a laser receiver, wherein the laser transmitter and the laser receiver are respectively arranged on the lifting platform at two sides of the deposition cavity;
the deposition cavity is used for the loose body, and glass windows are respectively arranged on two sides of the deposition cavity, so that the diameter of the loose body can be conveniently scanned by a laser transmitter and a receiver.
And a deposition material feeding device is arranged in the deposition cavity and is connected with the controller.
The rod lifting mechanism is a ball screw device and comprises a screw rod and a ball nut, the screw rod is vertically arranged on the rack, the upper end of the screw rod is connected with a servo motor and rotates, the ball screw converts the rotation of the motor into the up-and-down linear motion of the ball nut, and the ball nut drives the loosening body to move through the clamp.
The laser diameter measuring system is arranged on the lifting platform, a lifting driving mechanism of the laser diameter measuring system is the same as the rod lifting mechanism, and a ball screw device is adopted to convert the rotary motion of a motor into the up-and-down linear motion of the lifting platform.
The deposition material feeding device is a deposition blowtorch, the front end of the deposition blowtorch is provided with a mass flow controller for controlling each gas raw material, and the mass flow controller is connected with the controller, so that the flow of the deposition blowtorch can be accurately controlled in real time; the controller adopts Mitsubishi FX2N-128MT type PLC, can process the acquired data in real time, and realizes the adjustment of the flow of the mass flow controller according to the calculation result of the density of the loose body.
An online detection control method for density of a loose body comprises the steps of carrying out real-time weight measurement on the loose body in a deposition cavity through a weighing mechanism, carrying out real-time diameter measurement on the loose body through a laser diameter measurement system, uploading the measured value to a controller, obtaining real-time data in the deposition process of the loose body, and comparing the real-time data with an average density set value of a standard loose body to obtain a monitoring result;
and the controller adjusts the flow of the deposition material feeding device in the deposition cavity according to the comparison result, so as to correct the average density of the loose body in the deposition process.
And the laser diameter measuring system moves up and down in the deposition process to continuously measure the diameter of the whole loose body. The measurement process can be from top to bottom or from bottom to top. Taking the top-down as an example, when the diameter of the loose body measured by the laser diameter measuring system is 110% -130% of the diameter of the seed rod, the measured value is recorded. And then measuring and recording the diameter at intervals of 0.1-5 mm until the diameter is measured to be 0, and finishing sampling. The whole process obtains a set of data d of the diameter of the loose body1,d2，d3....dn。
And the controller is used for receiving the data provided by the weighing system and the laser diameter measuring system and calculating the volume and the density.
The calculation of the bulk volume V is:
The calculation principle and formula of the density are as follows:
during the deposition process, the controller calculates the volume V at the current moment0And record the currentWeight information M provided by a moment weighing system0. And after T minutes, the diameter measurement is carried out again by the laser diameter measuring system, and the weighing system samples again when the diameter measurement is finished. The controller obtains the volume V after T minutes1And weight information M1Then the average density ρ of the loose deposit in this time T can be determined. The calculation formula is as follows:
in order to ensure the accuracy of measurement, the time interval T between two measurements is not easy to be too small; the T is not easy to be too large for controlling the density of the product. T is preferably 5 to 30.
And the control system is used for controlling the gas flow of the blowtorch according to the calculated loose body density value. When the density is less than 2.2g/cm3The hydrogen flow rate of the cladding layer deposition burner is increased by 0.3-1.5L/min, and the hydrogen flow rate of the core layer deposition burner is increased by 0.1-0.3L/min. When the density is more than 2.5g/cm3The hydrogen flow rate of the cladding layer deposition burner is reduced by 0.3-1.5L/min, and the hydrogen flow rate of the core layer deposition burner is reduced by 0.1-0.3L/min.
In the VAD deposition process, the loose body is continuously lengthened along the axial direction, and the density value calculated through two times of measurement is the average density value on the newly increased length of the loose body.
For example: in the 5 th hour of VAD core rod deposition, the weight of the loose body measured by the loose body density online detection system is 2125.3g, the current volume is 988.5cm measured by the laser diameter measuring system and calculated by the controller3. After 20 minutes, the mass of the loose body was again determined to be 2265.9g and the volume 1057.7cm3。
The average deposition density in 20 minutes was 2.03g/cm, calculated by the controller3Less than 2.2g/cm of the expected value of the process3. After the control system obtains the calculated data, the hydrogen flow of the cladding layer deposition burner is increased by 0.5L/min, and the hydrogen flow of the core layer deposition burner is increased by 0.15L/min.
Within the next 20 minutes, the weight of the loose body became 2411.8g and the volume became 1122.5cm3And then, after the calculation, the data are sent to the computer,the average deposition density during this 20 minute deposition was 2.25g/cm3The process requirements are met.
Compared with the patent of publication number [ 209689666U ] in the background art, the utility model has the following beneficial effects: 1. density detection is carried out in the deposition process, the loose body does not need to be carried in the whole process, and the damage to the loose body in the carrying process is avoided; 2. in the deposition process, weighing in real time, measuring the volume of the loose body in real time, and calculating the average density of the deposition in the T time by using a more reasonable algorithm (the ratio of the mass increment to the volume increment in the T time), wherein the calculation result only depends on the deposition state in the T time and is irrelevant to the states of the loose body deposited in other times, so that the problem that the actual value of the average density is larger due to the large cone density can be completely avoided; 3. the loose body grows along the axial direction in the deposition process, so that the measurement of the average density of the loose body at different axial positions can be realized by monitoring through the controller, and the monitoring of the product condition is realized; 4. in the deposition process, the flow of the blast lamp can be automatically adjusted according to the measurement result of the density, so that the deposition density is controlled, and the production quality is improved.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, without departing from the principles of the present invention, several improvements can be made, and these improvements should also be regarded as the protection scope of the present invention without creative work.
Claims (8)
1. The utility model provides an online detection device of loose body density of optical fiber perform of VAD deposit which characterized in that: the seed rod weighing device comprises a rack, a weighing mechanism, a laser diameter measuring system, a controller and a deposition cavity, wherein the seed rod is arranged in the deposition cavity;
the weighing mechanism comprises a connecting piece, one end of the connecting piece is connected with a seed rod, the upper end of the seed rod is provided with a tension sensor, and the other end of the connecting piece is connected with the rack; the tension sensor and the laser diameter measuring system are connected with the controller.
2. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 1, wherein: the connecting piece include the clamp, carry excellent mechanism, the clamp is connected with the seed stick, the clamp passes through to carry excellent mechanism and is connected with the frame, carry excellent mechanism can follow frame vertical lift.
3. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 1, wherein: the laser diameter measuring system can vertically lift and comprises a lifting platform, a laser transmitter and a laser receiver, wherein the laser transmitter and the laser receiver are respectively arranged on the lifting platform at two sides of the deposition cavity;
the deposition cavity is used for the loose body, and glass windows are respectively arranged on two sides of the deposition cavity, so that the diameter of the loose body can be conveniently scanned by a laser transmitter and a receiver.
4. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 1, wherein: and a deposition material feeding device is arranged in the deposition cavity and is connected with the controller.
5. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 2, wherein: the rod lifting mechanism is a ball screw device and comprises a screw rod and a ball nut, the screw rod is vertically arranged on the rack, the upper end of the screw rod is connected with a servo motor and rotates, the ball screw converts the rotation of the motor into the up-and-down linear motion of the ball nut, and the ball nut drives the loosening body to move through the clamp.
6. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 1, wherein: the laser diameter measuring system is arranged on the lifting platform, a lifting driving mechanism of the laser diameter measuring system is the same as the rod lifting mechanism, and a ball screw device is adopted to convert the rotary motion of a motor into the up-and-down linear motion of the lifting platform.
7. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 1, wherein: the deposition material feeding device is a deposition blowlamp, the front end of the deposition blowlamp is provided with a mass flow controller for controlling each gas raw material, and the mass flow controller is connected with the controller.
8. The on-line detector for the density of the loose body of the VAD deposited optical fiber preform according to claim 7, wherein: the controller adopts Mitsubishi FX2N-128MT type PLC.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111574045A (en) * | 2020-05-25 | 2020-08-25 | 华能(泰安)光电科技有限公司 | VAD deposited optical fiber preform loose body density online detection device and control method |
| CN113772947A (en) * | 2021-09-17 | 2021-12-10 | 杭州金星通光纤科技有限公司 | System and method for controlling density of loose body of optical fiber preform rod in production process |
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2020
- 2020-05-25 CN CN202020886938.9U patent/CN212335018U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111574045A (en) * | 2020-05-25 | 2020-08-25 | 华能(泰安)光电科技有限公司 | VAD deposited optical fiber preform loose body density online detection device and control method |
| CN113772947A (en) * | 2021-09-17 | 2021-12-10 | 杭州金星通光纤科技有限公司 | System and method for controlling density of loose body of optical fiber preform rod in production process |
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