Device for preparing loose body of optical fiber preform by VAD method

Abstract

The utility model provides a device for preparing an optical fiber preform loose body by a VAD method, which comprises a reaction cavity, a movable rotating suspender is arranged at the upper part in the reaction cavity, and a cladding blowtorch and a core layer blowtorch are arranged on one side of the lower part in the cavity corresponding to the movable rotating suspender at an interval up and down, and are used for depositing a core layer and a cladding for forming an optical fiber preform base material; the device is characterized in that an exhaust pipe is arranged on one side of the reaction cavity, an exhaust valve is arranged on the exhaust pipe, an air supplementing pipeline is arranged at the top of the reaction cavity, an air supplementing valve is arranged on the air supplementing pipeline, and the opening degree of the air supplementing valve is controlled by a cavity pressure control system. The gulp valve is arranged at the top of the deposition cavity, and the opening degree of the gulp valve is controlled by the PID controller, so that the purpose of stabilizing the pressure of the deposition cavity is achieved. According to the utility model, the stability of core layer flame, cladding layer flame and cavity airflow in the deposition process can be ensured, so that key parameters such as the diameter of a preform core layer, the cladding ratio and the like are stably distributed along the length direction of the preform, and the quality and the qualified rate of the preform are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber preform manufacturing, in particular to a device for preparing an optical fiber preform loose body by a VAD method. Background Art

[0002] Optical fiber preform is the core raw material for manufacturing quartz optical fiber and is a key factor affecting the performance of optical fiber communication. Due to its high-tech content, high investment, high profit margin and other characteristics, it is in the core and high-end links of the optical fiber communication industry chain and is called the "crown jewel" of the optical communication industry. Usually, one type of optical fiber preform corresponds to only one type of optical fiber. At present, there are five mainstream preparation processes in the field of optical fiber preform manufacturing, namely OVD, MCVD, PCVD, VAD and two-step process. Axial vapor deposition (VAD) and external vapor deposition (OVD) are suitable for the production of large-size optical fiber preforms, and have the advantages of high production efficiency and low cost. It is generally believed that the manufacture of the core rod determines the transmission performance of the optical fiber, while outsourcing determines the manufacturing cost of the optical fiber. Combining these two processes is the best choice to reduce the cost of optical fiber preforms and achieve full synthesis of large-size low-water-peak optical fiber preforms.

[0003] Chinese patent CN02137584.4 discloses a method and device for manufacturing an optical fiber preform according to the present invention, wherein an airflow regulating member is arranged in a flange tube, and a rectified airflow is introduced downward from the upper end of the flange tube, so that the rectified airflow flows along the inner wall of the flange tube and the inner wall of the reaction container after passing through the airflow regulating member, and then is discharged from the exhaust port, in order to eliminate the phenomenon of airflow turbulence in the reaction container. Due to the characteristics of the VAD method, the preform loose body gradually grows and is continuously lifted upward, so that the space occupied by the loose body in the deposition cavity changes with time, that is, the influence of the loose body on the deposition cavity pressure is a non-steady-state process, and the flow guide alone cannot balance this non-steady state, but the patent does not mention this point, nor does it involve the control of the cavity pressure.

[0004] Chinese patent CN200910096092.7 discloses a device for manufacturing optical fiber preforms, in which an automatic pressure regulating valve for air supply, a pressure gauge, and a manual pressure regulating valve for air supply are arranged on the waste discharge pipe, and the pressure regulating device is connected to the main waste discharge pipe, and the main waste discharge pipe is connected to the waste discharge system, which can reduce the uneven temperature distribution caused by the shaking of the hydrogen-oxygen flame during the reaction. The main function of the waste discharge pipe is to discharge the waste gas generated by the reaction during the deposition process, as well as the silica dust that is not deposited on the preform loose body. The air supply valve is arranged on the waste discharge pipe, which not only adjusts the pressure of the deposition chamber, but also affects the discharge of the waste gas and the undeposited silica dust, which in turn affects the airflow stability of the deposition chamber and the accumulation of silica dust, which is not conducive to the stable deposition of the preform loose body. Utility Model Content

[0005] The utility model aims to provide a device for preparing optical fiber preform loose body by VAD method, which can stabilize the pressure of deposition cavity to improve the quality and qualified rate of preform.

[0006] The utility model is achieved in this way:

[0007] The utility model provides a device for preparing a loose body of an optical fiber preform rod by a VAD method, comprising a reaction chamber, a movable rotating suspension rod is arranged on the upper part of the reaction chamber, a cladding torch and a core layer torch are arranged at intervals above and below the movable rotating suspension rod on one side of the lower part of the chamber, and are used for depositing and forming a core layer and a cladding layer of an optical fiber preform rod mother material. The utility model is characterized in that an exhaust pipe is arranged on one side of the reaction chamber, an exhaust valve is arranged on the exhaust pipe, an air supply pipeline is arranged on the top of the reaction chamber, an air supply valve is arranged on the air supply pipeline, and the opening of the air supply valve is controlled by a chamber pressure control system.

[0008] In some optional embodiments, the cavity pressure control system includes a PID controller and a cavity pressure gauge.

[0009] In some optional embodiments, the exhaust valve is connected to an exhaust system.

[0010] In some optional implementation schemes, the distance between the air supply valve and the top of the cavity is not less than 1 m.

[0011] In some optional embodiments, a tower is included, and a vertical lifting device and a rotating device are installed in the vertical direction of the tower. The vertical lifting device is connected to a movable rotating boom, and a reaction chamber for deposition is correspondingly arranged below the movable rotating boom.

[0012] In some optional implementation schemes, the opening degree of the air supply valve is 20%-80%.

[0013] In some optional embodiments, the average value of the cavity pressure tested by the cavity pressure gauge is controlled within -300-50Pa.

[0014] In some optional embodiments, the average value of the cavity pressure tested by the cavity pressure gauge is controlled within -0.1-10Pa.

[0015] In some optional embodiments, the opening degree of the exhaust valve is 40%-60%.

[0016] The beneficial effects of the utility model are: 1. By arranging an air supply valve at the top of the deposition chamber, the opening of the air supply valve is controlled by a PID controller to achieve the purpose of stabilizing the pressure of the deposition chamber; 2. The mean value of the chamber pressure and the size of the chamber pressure fluctuation are adjustable, which is beneficial to compensate for the non-steady-state process of VAD deposition; 3. Different pressure controls can be set according to different product requirements, which is beneficial to the rapid switching of different products; 4. The stability of the core flame, cladding flame and cavity airflow can be guaranteed during the deposition process, so that key parameters such as the core diameter of the preform rod and the core-cladding ratio are stably distributed along the length direction of the rod, thereby improving the quality and qualified rate of the preform rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic diagram of the device for preparing loose bodies of optical fiber preform rods using the utility model VAD method.

[0019] Figure 2 The core cladding ratio in the elongation direction of the preform produced in the embodiment of the utility model is compared with the traditional method.

[0020] Figure 3 The core diameter of the preform rod in the elongation direction produced in the embodiment of the utility model is compared with the traditional method. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0029] Example 1

[0030] The present embodiment provides a device for preparing an optical fiber preform loose body by a VAD method, comprising a reaction chamber 4 and a tower, a vertical lifting device 2 and a rotating device 3 are arranged on the tower, the vertical lifting device 2 is connected to a movable rotating hanger, and the movable rotating hanger is connected to a preform 8 through a clamp 5, an exhaust pipe 11 is arranged on one side of the reaction chamber, an exhaust valve 12 is arranged on the exhaust pipe 11, the opening of the exhaust valve 12 is set to 50%, the exhaust valve 12 is connected to an exhaust system, an air supply pipeline 1 is arranged on the top of the reaction chamber, an air supply pipeline 1 is arranged on the air supply pipeline, an air supply valve 6 is arranged on the air supply pipeline, the initial opening of the air supply valve 6 is set to 10%, the air supply valve 6 is 1.5m away from the top of the chamber, and the air supply valve 6 is controlled by a chamber pressure control system, and the chamber pressure control system is composed of a PID controller 7 and a chamber pressure gauge 10, the average value of the chamber pressure tested by the pressure gauge 10 in the PID controller 7 is controlled at -50Pa, and the standard deviation of the chamber pressure tested by the pressure gauge 10 is controlled at 1Pa, and then a preform loose body 9 is prepared by a known VAD method. The utility model achieves the purpose of stabilizing the pressure of the deposition chamber by setting an air supply valve at the top of the deposition chamber, and the opening of the air supply valve is controlled by a PID controller. The utility model can ensure the stability of the core flame, cladding flame and cavity airflow during the deposition process, so that key parameters such as the core diameter and cladding ratio of the preform rod are stably distributed along the rod length direction, thereby improving the quality and qualified rate of the preform rod.

[0031] Comparative Example 2:

[0032] The other conditions are the same as those in Example 1, except that the conventional VAD method for preparing the optical fiber preform loose body using the air supply duct, air supply valve and cavity pressure control system is not provided on the top of the deposition chamber, and the preform loose body is prepared using the known VAD method.

[0033] like Figure 2 , 3 As shown, by comparing Example 1 with Example 2, it can be seen that the core diameter and the core-wrapping ratio of the preform rods manufactured using the traditional method in the elongation direction fluctuate greatly, while the performance of the present invention is stable.

[0034] The embodiments described above are part of the embodiments of the utility model, but not all of the embodiments. The detailed description of the embodiments of the utility model is not intended to limit the scope of the utility model claimed for protection, but only represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Claims

1. A device for preparing a loose body of an optical fiber preform by a VAD method, comprising a reaction chamber, a movable rotating suspension rod is arranged at the top of the reaction chamber, and a cladding burner and a core burner are arranged at intervals above and below the movable rotating suspension rod on one side of the lower chamber, for depositing a core layer and a cladding layer of an optical fiber preform mother material, characterized in that: An exhaust pipe is provided on one side of the reaction chamber, an exhaust valve is provided on the exhaust pipe, an air supply pipeline is provided on the top of the reaction chamber, an air supply valve is provided on the air supply pipeline, and the opening of the air supply valve is controlled by the chamber pressure control system.

2. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1, characterized in that: The cavity pressure control system includes a PID controller and a cavity pressure gauge.

3. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1 or 2, characterized in that: The exhaust valve is connected to the exhaust system.

4. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1 or 2, characterized in that: The distance between the air supply valve and the top of the cavity is not less than 1m.

5. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1 or 2, characterized in that: The invention comprises a tower frame, wherein a vertical lifting device and a rotating device are installed in the vertical direction of the tower frame. The vertical lifting device is connected with a movable rotating suspension rod, and a reaction chamber for deposition is correspondingly arranged below the movable rotating suspension rod.

6. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1 or 2, characterized in that: The opening degree of the air supply valve is 20%-80%.

7. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 2, characterized in that: The average value of the cavity pressure tested by the cavity pressure gauge is controlled within -300-50Pa.

8. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 7, characterized in that: The average value of the cavity pressure tested by the cavity pressure gauge is controlled within -0.1--10Pa.

9. The device for preparing a loose body of an optical fiber preform by a VAD method according to claim 1 or 2, characterized in that: The opening degree of the exhaust valve is 40%-60%.

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