A rotary joint connection structure for preparing optical fiber preform

Abstract

The present invention relates to the technical field of optical fiber preform manufacturing, and in particular to a rotary joint connection structure for preparing optical fiber preform. The structure comprises: a tubular receiving member, wherein the first connecting section is used to receive the rotary joint, and the second connecting section is threadedly connected to the core rod stabilizing sleeve; a tubular core rod stabilizing sleeve, wherein the third connecting section receives the second connecting section, and the fourth connecting section is inserted into the liner; the inner diameter of the first connecting section is larger than the inner diameter of the second connecting section, the inner diameter of the third connecting section is larger than the inner diameter of the fourth connecting section, a first vent hole is provided on the inner wall of the fourth connecting section, and a second vent hole corresponding thereto is provided on the inner wall of the second connecting section. The present invention effectively solves the technical problems in the prior art of the cumbersome operation steps of repeatedly replacing the special connecting sleeves during the production process of optical fiber preform, and the easy generation of pollution, which reduces the yield rate of optical fiber preform.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber preform manufacturing, and in particular to a rotary joint connection structure for preparing optical fiber preform. Background Art

[0002] Optical fiber preform, also known as optical fiber rod, is a high-purity quartz glass rod made of germanium ore and polycrystalline silicon by adding hydrogen, helium, etc., and undergoing high-temperature smelting and special process treatment. At present, the international methods for producing preforms mainly include improved chemical vapor deposition (MCVD), axial vapor deposition (VAD), external chemical vapor deposition (OVD) and plasma activated chemical vapor deposition (PCVD).

[0003] In the process of manufacturing optical fiber preforms by processes such as PVCD and MCVD, the sealing ring installed inside the rotary joint will produce wear debris due to rotational wear, and the special grease applied on the surface of the sealing ring will also fall off during the rotation process. After the wear debris and the detached lubricating material are brought into the quartz liner by the process gas flow, they will adhere to the inner wall of the tube, causing the obtained optical fiber preform to be scrapped due to impurities. In this regard, the patent document with the authorization announcement number CN219079357U discloses a rotary joint for PCVD and MCVD equipment, in which a protective tube that matches the gap of the feed pipe is fixedly connected to one end of the feed pipe, and the wear debris or lubricating material is blocked outside the gas path by the protective tube, so that debris cannot enter the process gas path, thereby ensuring the purity of the gas process raw materials and reducing the product scrap rate.

[0004] However, in the production process of optical fiber preform, the production processes such as rotary drawing, stretching and sintering usually require the introduction of special gases or vacuum, which requires the use of different rotary joints to achieve the purpose of gas transmission, air pressure control and vacuum control. The above rotary joints are not universal. In the prior art, a special connecting sleeve is required to connect the rotary joint, core rod and liner, and fix the installation position of the core rod in the liner. A special connecting sleeve needs to be replaced for each step to ensure the connection effect so that the special gas can smoothly pass through the gap between the rotary joint, liner and core rod. This makes the operation steps in the production of optical fiber preform cumbersome, and it is very easy to generate pollution during the replacement of the connecting sleeve, resulting in impurities in the produced optical fiber preform, reducing its yield rate. Summary of the invention

[0005] The present invention provides a rotary joint connection structure for preparing optical fiber preform rods, so as to solve the technical problems in the prior art that the operation steps of replacing a special connection sleeve multiple times during the production process of optical fiber preform rods are cumbersome, and pollution is easily generated, thereby reducing the yield rate of the optical fiber preform rods.

[0006] In order to solve the above problems, the rotary joint connection structure for preparing optical fiber preform provided by the present invention adopts the following technical solution:

[0007] A rotary joint connection structure for preparing an optical fiber preform, comprising:

[0008] The receiving piece is a tubular structure and includes a first connecting section and a second connecting section, wherein the first connecting section is used for inserting or screwing the rotary joint, and the second connecting section is screwed into the core rod stabilizing sleeve;

[0009] A mandrel stabilizing sleeve, comprising a third connecting section and a fourth connecting section, wherein the third connecting section is used to receive the second connecting section, and the fourth connecting section is used to be inserted into the liner, and the mandrel stabilizing sleeve is a tubular structure, and a mounting position for fixing the mandrel is formed inside the mandrel stabilizing sleeve;

[0010] The inner diameter of the first connecting section is larger than the inner diameter of the second connecting section, and the inner diameter of the third connecting section is larger than the inner diameter of the fourth connecting section;

[0011] A first ventilation hole is arranged on the inner wall of the fourth connecting section along the outer periphery of the mounting position, and the first ventilation hole extends along the length direction of the mandrel stabilizing sleeve. A second ventilation hole corresponding to the first ventilation hole is arranged on the inner wall of the second connecting section.

[0012] The beneficial effects of the rotary joint connection structure for preparing optical fiber preform provided by the present invention are:

[0013] 1. By providing a connected receiving piece and a core rod stabilizing sleeve, the first connecting section of the receiving piece is used to insert or screw the rotary joint, and the fourth connecting section of the core rod stabilizing sleeve is inserted into the liner to connect the liner and the rotary joint. The core rod is inserted into the core rod stabilizing sleeve to fix one end of the core rod, and the tube wall of the fourth connecting section is used as a partition to separate the core rod and the liner to ensure the gap between the core rod and the liner. By opening corresponding vents on the second connecting section and the fourth connecting section, the rotary joint is connected with the liner. The vents can not only serve as a channel for the reaction gas to enter, but also can be used to introduce protective inert gas, and can also be used as a channel for vacuuming the liner, so as to ensure that the rotary joint controls the gas transmission, air pressure and vacuum degree in the liner;

[0014] 2. During the production of optical fiber preform, the core rod stabilizing sleeve is maintained in connection with the liner and the core rod. If the rotary joint is a plug-in type rotary joint, the rotary structure is inserted into the receiving part of the pluggable rotary joint, and the receiving part is screwed into the third connecting section. If the rotary joint is a threaded rotary joint, the rotary joint is screwed into the receiving part with an internal thread, and the receiving part is screwed into the third connecting section. The installation is convenient and quick, and there is no need to re-fix the core rod and the liner, thereby avoiding the contaminants entering the liner due to re-fixing the core rod and the liner, thereby resulting in a low yield rate of the optical fiber preform.

[0015] Through the above arrangement, the present invention effectively solves the technical problems in the prior art of replacing the special connection sleeve multiple times during the production process of the optical fiber preform, which are cumbersome, easy to cause pollution and reduce the yield rate of the optical fiber preform.

[0016] Furthermore, there is an overlapping section between the third connecting section and the fourth connecting section, and the outer diameter of the overlapping section is the same as the outer diameter of the third connecting section, and the inner diameter of the overlapping section is the same as the inner diameter of the fourth connecting section.

[0017] Beneficial effect: The third connecting segment and the fourth connecting segment have an overlapping segment, the outer diameter of the overlapping segment is the same as the outer diameter of the third connecting segment, and the inner diameter is the same as the inner diameter of the fourth connecting segment, which can enhance the structural strength of the connecting part between the third connecting segment and the fourth connecting segment, making it more stable and reliable when subjected to external force.

[0018] Furthermore, the number of the first ventilation holes is 8 to 12, and the radial dimensions of the first ventilation holes and the second ventilation holes are equal and both are greater than or equal to 2 mm.

[0019] Furthermore, 8 to 12 of the first ventilation holes are evenly spaced on the inner wall of the fourth connecting section.

[0020] Furthermore, the outer periphery of the fourth connecting section has a V-shaped groove surrounding its surface so as to install the first sealing member.

[0021] Beneficial effect: By providing a V-shaped groove around the surface of the fourth connecting section and installing the first seal in the V-shaped groove, the sealing between the fourth connecting section and the liner can be ensured, thereby ensuring the effect of gas transmission or negative pressure vacuuming.

[0022] Furthermore, the number of the V-shaped grooves is three, and the three V-shaped grooves are evenly spaced around the periphery of the fourth connecting section.

[0023] Furthermore, the first sealing member is a fluororubber O-ring or a circular graphite sheet.

[0024] Beneficial effect: The first seal is an O-ring or an annular graphite sheet. When the operating temperature is not more than 230°C, a fluororubber O-ring can be selected as the first seal. When the operating temperature is greater than 230°C and not more than 500°C, an annular graphite sheet can be selected as the first seal to meet the requirements of the operating conditions.

[0025] Furthermore, a fixing sleeve is provided in the second connecting segment, the inner diameter of the fixing sleeve is the same as the inner diameter of the fourth connecting segment, the length of the fixing sleeve is greater than the length of the second connecting segment, and one end thereof facing the first connecting segment is flush with the end face of the second connecting segment, and the other end has an annular section, and the inner circumference of the end of the fourth connecting segment facing the fixing sleeve also has an annular section, and the two annular sections cooperate with each other to form an installation position for installing the second seal.

[0026] Beneficial effect: By setting annular cross-sections at the opposite ends of the second connecting section and the fourth connecting section, and utilizing the mutual cooperation of the two annular cross-sections to form the installation position of the second sealing member, the airtightness of the connection between the second connecting member and the fourth connecting member can be enhanced by the second sealing member, thereby ensuring the effect of gas transmission or negative pressure vacuuming.

[0027] Furthermore, the second sealing member is a fluororubber O-ring or a circular graphite sheet.

[0028] Beneficial effect: The second seal is an O-ring or an annular graphite sheet. When the operating temperature is not more than 230°C, a fluororubber O-ring can be selected as the second seal. When the operating temperature is greater than 230°C and not more than 500°C, an annular graphite sheet can be selected as the second seal to meet the requirements of the operating conditions.

[0029] Furthermore, the outer surface of the first connecting section is knurled, and the outer surface of the third connecting section is knurled.

[0030] Beneficial effect: By arranging knurling on the outer surfaces of the first connecting section and the third connecting section, it is convenient to hold the receiving part and the core rod stabilizing sleeve, and it is convenient to install and disassemble the receiving part, the rotary joint and the core rod stabilizing sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0032] Figure 1 This is a schematic diagram of the structure of the receiving member provided by the present invention;

[0033] Figure 2 for Figure 1A cross-sectional view of the middle receiving member;

[0034] Figure 3 This is a schematic structural diagram of the core rod stabilizing sleeve provided by the present invention;

[0035] Figure 4 for Figure 3 A cross-sectional view of the core rod stabilizing sleeve;

[0036] Figure 5 This is a schematic diagram of the application structure of the rotary joint connection structure for preparing an optical fiber preform provided by the present invention when receiving a straight-insert type rotary joint;

[0037] Figure 6 The present invention is a schematic diagram of the application structure of the rotary joint connection structure for preparing optical fiber preform provided by the present invention when receiving a threaded rotary joint.

[0038] Description of reference numerals:

[0039] 1. First connecting section; 2. Second connecting section; 3. Third connecting section; 4. Fourth connecting section; 5. Liner; 6. Mandrel; 7. Direct plug-in rotary joint; 8. Threaded rotary joint; 9. First vent hole; 10. Second vent hole; 11. Overlapping section; 12. V-shaped groove; 13. First sealing member; 14. Fixing sleeve; 15. Annular section; 16. Second sealing member; 17. Third sealing member; 18. Back-off groove. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0041] It should be noted that the main concept of the rotary joint connection structure for preparing optical fiber preform provided by the present invention is: by setting mutually connected receiving parts and core rod stabilizing sleeve as the connection structure, the receiving part is used to insert or screw the rotary joint, and the core rod stabilizing sleeve is inserted in the liner to realize the connection between the rotary joint, the liner and the core rod; the core rod is fixed by the core rod stabilizing sleeve, and the gap between the core rod and the liner is ensured, and by opening corresponding vents on the receiving part and the core rod stabilizing sleeve, the gas transmission between the rotary joint and the liner can be ensured, thereby ensuring the control of the rotary joint on the gas transmission, air pressure and vacuum degree in the liner; by screwing the receiving part and the core rod stabilizing sleeve, the connection is convenient, and the receiving part matching it can be replaced according to the type of the rotary joint. During the replacement process, there is no need to re-fix the core rod and the liner, which can avoid the contaminants from entering the liner due to re-fixing the core rod and the liner, thereby resulting in a low yield rate of the optical fiber preform.

[0042] After introducing the basic principle of the present invention, various non-limiting embodiments of the present invention are described in detail below. The number of any element in the drawings is for illustration and not for limitation, and any naming is only for distinction and does not have any limiting meaning.

[0043] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0044] Embodiment 1 of the rotary joint connection structure for preparing optical fiber preform provided by the present invention:

[0045] like Figures 1 to 6 As shown, the rotary joint connection structure for preparing optical fiber preform includes a receiving member and a core rod stabilizing sleeve connected to the receiving member.

[0046] About the socket. The socket is a tubular structure and includes a first connecting section 1 and a second connecting section 2. The first connecting section 1 is used for inserting or screwing the rotary joint, and the second connecting section 2 is screwed into the core rod stabilizing sleeve. The inner diameter of the first connecting section 1 is larger than the inner diameter of the second connecting section 2, and its outer diameter is larger than the outer diameter of the second connecting section 2.

[0047] Specifically, when the rotary joint is a plug-in type rotary joint 7, there is a light hole in the first connecting section 1, and two third seals 17 need to be arranged between the outer periphery of the plug-in type rotary joint 7 and the inner wall of the first connecting section 1; when the rotary joint is a threaded type rotary joint 8, the inner wall of the first connecting section 1 has an internal thread to facilitate the screw-on installation of the threaded type rotary joint 8.

[0048] Specifically, the outer surface of the first connecting section 1 is knurled so as to hold the receiving part and realize the disassembly and assembly between the receiving part and the rotary joint and the core rod stabilizing sleeve.

[0049] Specifically, a fixing sleeve 14 is provided in the second connecting section 2 , and the length of the fixing sleeve 14 is greater than the length of the second connecting section 2 . The left end of the fixing sleeve 14 is flush with the left end of the second connecting section 2 .

[0050] Regarding the core rod stabilizing sleeve. The core rod stabilizing sleeve includes a third connecting segment 3 and a fourth connecting segment 4. The third connecting segment 3 is used to receive the second connecting segment 2, and the fourth connecting segment 4 is used to be inserted into the liner 5. The core rod stabilizing sleeve is a tubular structure, and a mounting position for fixing the core rod 6 is formed inside the third connecting segment 3. The inner diameter of the third connecting segment 3 is larger than the inner diameter of the fourth connecting segment 4, and the outer diameter of the third connecting segment 3 is larger than the outer diameter of the fourth connecting segment 4. The inner diameter of the fourth connecting segment 4 is the same as the inner diameter of the fixing sleeve 14.

[0051] Specifically, an overlap section 11 is provided between the third connecting section 3 and the fourth connecting section 4 . The outer diameter of the overlap section 11 is the same as that of the third connecting section 3 , and the inner diameter thereof is the same as that of the fourth connecting section 4 .

[0052] Specifically, the right end of the third connecting section 3 has a relief groove 18 .

[0053] Specifically, the second connecting section 2 is screwed into the third connecting section 3, and a fourth seal (not shown in the figure) and a gasket (not shown in the figure) are arranged between the second connecting section 2 and the third connecting section 3 to ensure the sealing effect; the length of the third connecting section 3 is greater than the length of the second connecting section 2, so that a gas buffer zone is formed in the third connecting section 3 between the second connecting section 2 and the overlapping section 11.

[0054] Specifically, the outer surface of the third connecting section 3 is knurled.

[0055] In order to ensure the gas transportation, air pressure control and vacuum degree control between the rotary joint and the liner 5, twelve evenly spaced first air holes 9 are arranged on the inner wall of the fourth connecting section 4 along the outer circumference of the mounting position for fixing the core rod 6. The extension direction of the first air holes 9 is the same as the length direction of the core rod stabilizing sleeve. Second air holes 10 corresponding to the number, size and position of the first air holes 9 are arranged on the inner wall of the second connecting section 2. The radial dimensions of the first air holes 9 and the second air holes 10 are both greater than 2 mm to ensure the ventilation area of ​​the gas.

[0056] The first vent hole 9 and the second vent hole 10 can not only serve as a passage for the reaction gas to enter, but also can be used to introduce protective inert gas, and can also serve as a passage for evacuating the liner tube 5 .

[0057] In order to ensure the sealing effect between the core rod stabilizing sleeve and the liner 5, three V-grooves 12 are opened on the outer periphery of the fourth connecting section 4, and the three V-grooves 12 are evenly spaced on the outer periphery of the fourth connecting section 4. The sealing effect is ensured by installing a first seal 13 in the V-groove 12.

[0058] In addition, the right end of the fixing sleeve 14 has an annular section 15, and the left end of the fourth connecting section 4 has an annular section 15 matching the same. The two annular sections 15 cooperate with each other to form a mounting position for mounting the second sealing member 16. The core rod 6 is firmly fixed by the second sealing member 16 to ensure the position of the core rod 6. At the same time, the second sealing member 16 can also play a sealing role to ensure a good sealing effect under vacuum or a certain positive pressure.

[0059] It should be noted that, when the operating temperature is not greater than 230°C, the first seal 13, the second seal 16, the third seal 17 and the fourth seal are all fluororubber O-rings, and the core rod stabilizing sleeve is made of Teflon material or 316L stainless steel; when the operating temperature is greater than 230°C and not greater than 500°C, the first seal 13, the second seal 16, the third seal 17 and the fourth seal are all annular graphite sheets, and the core rod stabilizing sleeve is made of 316L stainless steel or a high-temperature resistant alloy.

[0060] The working principle of the rotary joint connection structure for preparing optical fiber preform provided by the present invention is: first install the first sealing member 13 in the V-shaped groove 12, then insert the fourth connection section 4 into the liner 5, and make the core rod 6 pass through the core rod stabilizing sleeve and extend to the fixing sleeve 14, install the second sealing member 16 on the annular section 15 of the fourth connection section 4, then select a suitable receiving member, screw the second connection section 2 into the third connection section 3 and make the right end of the fixing sleeve 14 abut against the second sealing member 16, if the rotary joint is a straight plug-in rotary joint 7, then the first connection section 1 is a light hole, and two third sealing members 17 are arranged between the straight plug-in rotary joint 7 and the inner wall of the first connection section 1, if the rotary joint is a threaded rotary joint 8, then the inner wall of the first connection section 1 has an internal thread, and the threaded rotary joint 8 is threadedly connected to the first connection section 1;

[0061] If the operating temperature is not greater than 230°C, the first seal 13, the second seal 16, the third seal 17 and the fourth seal are all fluororubber O-rings, and the core rod stabilizing sleeve is made of Teflon material or 316L stainless steel; if the operating temperature is greater than 230°C and not greater than 500°C, the first seal 13, the second seal 16, the third seal 17 and the fourth seal are all annular graphite sheets, and the core rod stabilizing sleeve is made of 316L stainless steel or a high-temperature resistant alloy.

[0062] Embodiment 2 of the rotary joint connection structure for preparing optical fiber preform provided by the present invention:

[0063] The main difference between it and Example 1 is:

[0064] In Example 1, the number of V-shaped grooves is three.

[0065] In this embodiment, the number of V-shaped grooves is determined according to specific usage conditions.

[0066] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "width", "horizontal", "top", "bottom", "inside", "outside" and the like, which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0067] In addition, in the description of this specification, “plurality” means at least two, for example, two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. A rotary joint connection structure for preparing an optical fiber preform, characterized in that: include: The receiving piece is a tubular structure and includes a first connecting section and a second connecting section, wherein the first connecting section is used for inserting or screwing the rotary joint, and the second connecting section is screwed into the core rod stabilizing sleeve; A mandrel stabilizing sleeve, comprising a third connecting section and a fourth connecting section, wherein the third connecting section is used to receive the second connecting section, and the fourth connecting section is used to be inserted into the liner, and the mandrel stabilizing sleeve is a tubular structure, and a mounting position for fixing the mandrel is formed inside the mandrel stabilizing sleeve; The inner diameter of the first connecting section is larger than the inner diameter of the second connecting section, and the inner diameter of the third connecting section is larger than the inner diameter of the fourth connecting section; A first vent hole is arranged on the inner wall of the fourth connecting section along the outer periphery of the mounting position, the first vent hole extending along the length direction of the mandrel stabilizing sleeve, and a second vent hole corresponding to the first vent hole is arranged on the inner wall of the second connecting section; The second connecting section has a fixing sleeve therein, the inner diameter of the fixing sleeve is the same as the inner diameter of the fourth connecting section, the length of the fixing sleeve is greater than the length of the second connecting section, and one end of the fixing sleeve facing the first connecting section is flush with the end face of the second connecting section, and the other end has an annular section, and the inner circumference of the end of the fourth connecting section facing the fixing sleeve also has an annular section, and the two annular sections cooperate with each other to form an installation position for installing the second seal.

2. The rotary joint connection structure for preparing an optical fiber preform according to claim 1, characterized in that: An overlapping section is provided between the third connecting section and the fourth connecting section. The outer diameter of the overlapping section is the same as the outer diameter of the third connecting section, and the inner diameter of the overlapping section is the same as the inner diameter of the fourth connecting section.

3. The rotary joint connection structure for preparing an optical fiber preform according to claim 2, characterized in that: The number of the first ventilation holes is 8 to 12, and the radial dimensions of the first ventilation holes and the second ventilation holes are equal and both are greater than or equal to 2 mm.

4. The rotary joint connection structure for preparing an optical fiber preform according to claim 3, characterized in that: 8 to 12 of the first ventilation holes are evenly spaced on the inner wall of the fourth connecting section.

5. The rotary joint connection structure for preparing an optical fiber preform according to any one of claims 1 to 4, characterized in that: The outer periphery of the fourth connecting section has a V-shaped groove surrounding the surface thereof so as to install the first sealing member.

6. The rotary joint connection structure for preparing optical fiber preform according to claim 5, characterized in that: The number of the V-shaped grooves is three, and the three V-shaped grooves are evenly spaced around the outer circumference of the fourth connecting section.

7. The rotary joint connection structure for preparing an optical fiber preform according to claim 6, characterized in that: The first sealing member is a fluororubber O-ring or an annular graphite sheet.

8. The rotary joint connection structure for preparing an optical fiber preform according to claim 7, characterized in that: The second sealing member is a fluororubber O-ring or an annular graphite sheet.

9. The rotary joint connection structure for preparing an optical fiber preform according to any one of claims 1 to 4, characterized in that: The outer surface of the first connecting section is knurled, and the outer surface of the third connecting section is knurled.

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