Pressure control device for optical fiber preform deposition and optical fiber preform deposition system

Abstract

The utility model belongs to the technical field of optical fiber manufacturing, and discloses a pressure control device for optical fiber preform deposition and an optical fiber preform deposition system. The pressure control device comprises a controller, and a pressure sensor, a pumping and draining valve and two flow control valves with different measuring ranges which are respectively connected with the controller; two flow control valves with different measuring ranges are arranged on a first pipeline for introducing protective gas, and the first pipeline is communicated with the cavity; the cavity is communicated with the outlet end of the liner tube, and the inlet end of the liner tube is communicated with a second pipeline for introducing process gas; and the pressure sensor and the pumping and draining valve are respectively arranged on the cavity. On the basis of the device, the utility model further provides an optical fiber preform deposition system. According to the utility model, not only can the precision requirement of pressure regulation be met, but also the upper limit of pressure control can be reached, and the pressure in the pipe can be continuously and accurately controlled.

Description

Technical Field

[0001] This utility model belongs to the field of optical fiber manufacturing technology, and more specifically, relates to a pressure control device and an optical fiber preform deposition system for optical fiber preform deposition. Background Technology

[0002] During the deposition process of preforms, the temperature varies at different stages, the flow rate of the process gas changes continuously, and the inner diameter of the liner (e.g., a glass liner) gradually decreases with the processing. Furthermore, dust is generated inside the liner during deposition. These factors cause pressure variations within the liner, leading to uneven deposition and defects such as bulging on the outer wall of the liner. Therefore, it is necessary to introduce an adjustable flow rate of gas into the liner during deposition to control the pressure and ensure the overall uniformity of the preforms.

[0003] However, existing pressure control devices for optical fiber preform deposition (i.e., devices for pressure control within the liner) typically employ only a single-range flow control valve. If a large-range flow control valve is used, the accuracy of pressure regulation within the liner may not meet process requirements; conversely, if a high-precision, small-range flow control valve is used, while the required accuracy may be achieved, the upper limit of pressure control may not be reached. Therefore, in the specific application scenarios of optical fiber preform deposition, how to design a pressure control device that achieves both the required accuracy of pressure regulation and the upper limit of pressure control is a key issue that needs to be addressed in this field. Utility Model Content

[0004] This invention provides a pressure control device and a fiber optic preform deposition system for fiber optic preform deposition, thereby solving the problem that existing pressure control devices for fiber optic preform deposition cannot simultaneously meet the requirements of both pressure regulation accuracy and range.

[0005] This utility model provides a pressure control device for optical fiber preform deposition, comprising: a controller, and a pressure sensor, a pumping valve, and two flow control valves with different ranges respectively connected to the controller;

[0006] The two flow control valves with different ranges are installed on the first pipeline for introducing protective gas, and the first pipeline is connected to the cavity; the cavity is connected to the outlet end of the liner, and the inlet end of the liner is connected to the second pipeline for introducing process gas; the pressure sensor and the exhaust valve are respectively installed on the cavity.

[0007] Preferably, the two flow control valves configured with different ranges include a first flow control valve with a first range and a second flow control valve with a second range; the first range is 0 to Q1, and the value of Q1 ranges from 20 L / min to 30 L / min; the second range is 0 to Q2, and the value of Q2 ranges from 4 L / min to 6 L / min.

[0008] Preferably, the first pipeline includes a base pipeline and a regulating pipeline connected in parallel, the first flow control valve is installed on the base pipeline, and the second flow control valve is installed on the regulating pipeline.

[0009] Preferably, the first flow control valve is used to control the basic pipeline to supply a fixed flow rate of basic protective gas, and the second flow control valve is used to control the regulating pipeline to supply an adjustable flow rate of regulating protective gas.

[0010] Preferably, the pressure control accuracy of the pressure control device for optical fiber preform deposition is within ±2 Pa.

[0011] Preferably, the opening range of the extraction valve is 0 to 100%.

[0012] Preferably, the initial opening degree of the extraction valve is set to 45% to 55%.

[0013] Preferably, the controller is a PID controller; the PID controller is used to control the opening degree of the extraction valve and the opening degree of the two flow control valves configured with different ranges based on the detected pressure value obtained by the pressure sensor and the preset target pressure value.

[0014] Preferably, the protective gas is nitrogen.

[0015] On the other hand, this utility model provides an optical fiber preform deposition system, including: an exhaust gas treatment device, a protective gas source, a process gas source, and a pressure control device for optical fiber preform deposition as described above.

[0016] The exhaust gas treatment device is connected to the exhaust valve in the pressure control device for optical fiber preform deposition, the protective gas source is connected to the first pipeline in the pressure control device for optical fiber preform deposition, and the process gas source is connected to the second pipeline in the pressure control device for optical fiber preform deposition.

[0017] One or more technical solutions provided in this utility model have at least the following technical effects or advantages:

[0018] This invention, tailored to the specific application requirements of optical fiber preform deposition, provides a pressure control device comprising a controller, a pressure sensor, a suction / discharge valve, and two flow control valves with different flow ranges, all connected to the controller. The two flow control valves are installed on a first pipeline for introducing protective gas, which is connected to a cavity. The cavity is connected to the outlet end of a liner, and the inlet end of the liner is connected to a second pipeline for introducing process gas. The pressure sensor and suction / discharge valve are respectively installed on the cavity. This invention utilizes two flow control valves with different flow ranges to achieve both the required precision in pressure regulation and the upper limit of pressure control. During the optical fiber preform deposition process, the pressure control device provided by this invention can continuously and accurately control the pressure inside the tube, thereby ensuring the overall uniformity of the preform. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a pressure control device for optical fiber preform deposition provided in Embodiment 1 of this utility model.

[0020] Among them, 1-liner, 2-cavity, 3-first flow control valve, 4-second flow control valve, 5-pressure sensor, and 6-extraction valve. Detailed Implementation

[0021] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0022] Example 1:

[0023] Example 1 provides a pressure control device for optical fiber preform deposition, see [link to example]. Figure 1 The system includes: a controller, and a pressure sensor 5, a suction / discharge valve 6, and two flow control valves with different ranges respectively connected to the controller; the two flow control valves with different ranges are installed on a first pipeline for introducing protective gas, and the first pipeline is connected to a cavity 2; the cavity 2 is connected to the outlet end of a liner 1, and the inlet end of the liner 1 is connected to a second pipeline for introducing process gas; the pressure sensor 5 and the suction / discharge valve 6 are respectively installed on the cavity 2.

[0024] The two flow control valves configured with different flow ranges include a first flow control valve 3 with a first flow range and a second flow control valve 4 with a second flow range; the first flow range is 0 to Q1, and the value of Q1 ranges from 20 L / min to 30 L / min; the second flow range is 0 to Q2, and the value of Q2 ranges from 4 L / min to 6 L / min.

[0025] The first pipeline includes a base pipeline and a regulating pipeline connected in parallel. The first flow control valve 3 is installed on the base pipeline, and the second flow control valve 4 is installed on the regulating pipeline.

[0026] The first flow control valve 3 is used to control the basic pipeline to supply a fixed flow rate of basic protective gas, and the second flow control valve 4 is used to control the regulating pipeline to supply an adjustable flow rate of regulating protective gas.

[0027] The pressure control accuracy of the pressure control device used for optical fiber preform deposition is within ±2Pa.

[0028] The opening range of the extraction valve 6 is 0 to 100%. For example, the initial opening of the extraction valve 6 can be set to 45% to 55%.

[0029] The controller is a PID controller; the PID controller is used to control the opening degree of the extraction valve 6 and the opening degree of the two flow control valves with different ranges based on the detected pressure value obtained by the pressure sensor 5 and the preset target pressure value.

[0030] For example, this utility model can first set the initial opening of the extraction valve 6 and the opening of the first flow control valve 3 based on historical data or other references, and then focus on controlling the opening of the second flow control valve 4 during the optical fiber preform deposition process.

[0031] The protective gas may be nitrogen or other gases depending on the application requirements.

[0032] Taking nitrogen as an example of the protective gas, this invention uses the pressure sensor 5 to measure the real-time pressure inside the liner 1 (e.g., a glass liner), uses a large-range nitrogen control valve (i.e., the first flow control valve 3) to introduce a fixed large flow of nitrogen into the liner 1, and the exhaust valve 6 opens to a certain degree to discharge the dust and exhaust gas inside the liner 1 into the subsequent tail gas treatment device. The high-precision small-range nitrogen flow control valve (i.e., the second flow control valve 4) is used to precisely control the flow rate injected into the liner 1 to achieve the purpose of precisely controlling the pressure inside the pipe.

[0033] The following are examples illustrating several specific situations where pressure regulation is performed using the pressure control device provided by this utility model:

[0034] (1) When the flow rate of the process gas decreases, the pressure inside the liner 1 will also decrease. As a result, the liner 1 will dent during the high-temperature heating process. At this time, by increasing the opening of the high-precision small-range nitrogen flow control valve (i.e., the second flow control valve 4) to supplement nitrogen into the liner 1, the pressure can be increased to ensure that the liner 1 does not dent. The reverse is also true.

[0035] (2) As the deposition process proceeds, the inner diameter of the liner 1 will decrease, and the pressure inside the liner 1 will increase. Therefore, the liner 1 will bulge during high-temperature heating. At this time, by reducing the opening of the high-precision, small-range nitrogen flow control valve (i.e., the second flow control valve 4), less nitrogen is supplied to the liner 1, thus reducing the pressure and preventing the liner 1 from bulging. Conversely, the opposite is also true.

[0036] (3) Dust inside the liner 1 will adhere to the exhaust outlet, causing the exhaust flow rate to decrease and the pressure inside the liner 1 to increase. Then the liner 1 will bulge during the high-temperature heating process. At this time, by reducing the opening of the high-precision small-range nitrogen flow control valve (i.e. the second flow control valve 4), less nitrogen is supplied to the liner 1, which can reduce the pressure and ensure that the liner 1 does not bulge.

[0037] (4) As the temperature rises, the pressure inside the liner 1 will increase, and the liner 1 will bulge during the high-temperature heating process. At this time, by reducing the opening of the high-precision small-range nitrogen flow control valve (i.e., the second flow control valve 4), less nitrogen is supplied to the liner 1, which can reduce the pressure and ensure that the liner 1 does not bulge. The opposite is also true.

[0038] As illustrated by the examples above, many factors can cause pressure changes within the pipe, such as increases or decreases in process temperature, the flow rate of process gas, decreases in pipe diameter, dust adhesion, and the flow rate of extraction. Regardless of the cause, the pressure sensor 5 in the pressure control device provided by this invention measures a real-time pressure value and feeds it back to the controller. The controller then performs PID calculations by comparing the detected pressure value with the set target pressure value to obtain a corresponding control signal. This signal is then used to control the high-precision, small-range nitrogen flow control valve for precise flow control, thereby achieving accurate pressure control.

[0039] The present invention will be further illustrated below with specific parameters.

[0040] Using the pressure control device for optical fiber preform deposition provided in Example 1, the following control steps can be performed:

[0041] S1, control the large-range nitrogen control valve (i.e. the first flow control valve 3) to give a basic nitrogen flow rate of 25L / min to the end of the liner 1 (i.e. the outlet end), set the initial opening of the extraction valve 6 to 50%, and at this time the pressure sensor 5 measures a basic pressure value of 1200mbar.

[0042] S2, the temperature of the liner 1 is raised to 1000℃, and process gas is introduced into the tube at a flow rate of 500mL / min. At this time, the pressure value measured by the pressure sensor 5 is 1250mbar.

[0043] S3, the range of the high-precision small-range nitrogen control valve (i.e. the second flow control valve 4) is 0 to 5 L / min, and the set target pressure value is 1500 mbar. At this time, the controller uses the PID algorithm to give a changing precise small-range nitrogen flow value in real time, so that the pressure in the pipe gradually approaches 1500 mbar.

[0044] S4. As the processing progresses, the base pressure gradually increases, and the flow rate of the high-precision small-range nitrogen control valve (i.e., the second flow control valve 4) gradually decreases to ensure that the pressure inside the pipe is maintained at around 1500 mbar.

[0045] S5, when the flow rate of the high-precision small-range nitrogen control valve (i.e. the second flow control valve 4) decreases to 0L / min, if the pressure inside the pipe is still greater than the set value of 1500mbar, the opening of the extraction valve 6 can be increased to reduce the base pressure. At this time, the pressure control device can still use the PID algorithm to accurately control the flow rate to achieve precise pressure control to 1500mbar.

[0046] In summary, the pressure control device for optical fiber preform deposition provided in Example 1 can meet both the accuracy requirements of pressure regulation and the upper limit of pressure control, and can continuously and accurately control the pressure inside the tube.

[0047] Example 2:

[0048] Example 2 provides an optical fiber preform deposition system, comprising: an exhaust gas treatment device, a protective gas source, a process gas source, and a pressure control device for optical fiber preform deposition as described in Example 1. The exhaust gas treatment device is connected to the exhaust valve in the pressure control device for optical fiber preform deposition, the protective gas source is connected to a first pipeline in the pressure control device for optical fiber preform deposition, and the process gas source is connected to a second pipeline in the pressure control device for optical fiber preform deposition.

[0049] In addition, the optical fiber preform deposition system may also include a heating device, other monitoring and sensing devices, a moving device, etc. This utility model does not involve specific improvements to the above-mentioned devices, so they will not be described in detail. They can be understood based on the prior art in this field.

[0050] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A pressure control device for optical fiber preform deposition, characterized in that, Includes: a controller, and a pressure sensor, a pumping valve, and two flow control valves with different ranges respectively connected to the controller; The two flow control valves with different ranges are installed on the first pipeline for introducing protective gas, and the first pipeline is connected to the cavity; the cavity is connected to the outlet end of the liner, and the inlet end of the liner is connected to the second pipeline for introducing process gas; the pressure sensor and the exhaust valve are respectively installed on the cavity.

2. The pressure control device for optical fiber preform deposition according to claim 1, characterized in that, The two flow control valves configured with different ranges include a first flow control valve with a first range and a second flow control valve with a second range; the first range is 0 to Q1, and the value of Q1 ranges from 20 L / min to 30 L / min; the second range is 0 to Q2, and the value of Q2 ranges from 4 L / min to 6 L / min.

3. The pressure control device for optical fiber preform deposition according to claim 2, characterized in that, The first pipeline includes a base pipeline and a regulating pipeline connected in parallel. The first flow control valve is installed on the base pipeline, and the second flow control valve is installed on the regulating pipeline.

4. The pressure control device for optical fiber preform deposition according to claim 3, characterized in that, The first flow control valve is used to control the basic pipeline to supply a fixed flow rate of basic protective gas, and the second flow control valve is used to control the regulating pipeline to supply an adjustable flow rate of regulating protective gas.

5. The pressure control device for optical fiber preform deposition according to claim 1, characterized in that, The pressure control accuracy of the pressure control device used for optical fiber preform deposition is within ±2Pa.

6. The pressure control device for optical fiber preform deposition according to claim 1, characterized in that, The opening range of the extraction valve is 0 to 100%.

7. The pressure control device for optical fiber preform deposition according to claim 6, characterized in that, The initial opening degree of the extraction valve is set to 45% to 55%.

8. The pressure control device for optical fiber preform deposition according to claim 1, characterized in that, The controller is a PID controller; the PID controller is used to control the opening degree of the extraction valve and the opening degree of the two flow control valves with different ranges based on the detected pressure value obtained by the pressure sensor and the preset target pressure value.

9. The pressure control device for optical fiber preform deposition according to claim 1, characterized in that, The protective gas used is nitrogen.

10. An optical fiber preform deposition system, characterized in that, include: The exhaust gas treatment device, the protective gas source, the process gas source, and the pressure control device for optical fiber preform deposition as described in any one of claims 1-9. The exhaust gas treatment device is connected to the exhaust valve in the pressure control device for optical fiber preform deposition, the protective gas source is connected to the first pipeline in the pressure control device for optical fiber preform deposition, and the process gas source is connected to the second pipeline in the pressure control device for optical fiber preform deposition.

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