Device and method for manufacturing optical fiber preform

Abstract

The invention relates to a device and method for manufacturing an optical fiber preform, and the device comprises a deposition cavity which is internally provided with an upper rotating chuck and a lower rotating chuck which are used for clamping and rotating a target rod; the blowtorch mechanism comprises a blowtorch which reciprocates along the height direction of the deposition cavity so as to cover all deposition areas of the target rod; the air draft mechanism comprises a plurality of sub air ducts which are arranged opposite to the blow lamp and are sequentially arranged in the height direction of the deposition cavity; and an air volume adjusting valve for adjusting the opening degree according to the height change of the blowtorch is arranged in each sub-air duct. According to the invention, the blowtorch which reciprocates along the height direction of the deposition cavity to cover all deposition areas of the target rod is arranged, so that the whole-course deposition of the target rod is realized. All the blowtorches act on all the deposition areas of the target rod, repeated deposition is carried out on all the deposition areas of the target rod through multiple times of turning back of the blowtorches, and deposition nonuniformity caused by individual differences of the blowtorches can be eliminated even if individual blowtorches break down.

Description

Technical Field

[0001] The present application relates to the technical field of optical fiber preform processing, and in particular to a manufacturing device and method for an optical fiber preform. Background Art

[0002] The outside vapor deposition method (OVD method) is an important method for preparing large-size optical fiber preforms and synthetic quartz glass cylinders. In simple terms, silicon-containing raw materials such as silicon tetrachloride or octamethylcyclotetrasiloxane, combustion gases such as hydrogen or natural gas, and oxygen are introduced into a blowtorch, and silica powder is generated through combustion reaction and deposited on the target rod to form a porous silica loose body. The porous silica loose body is then sintered into a non-porous silica glass body in a helium-chlorine atmosphere or in a vacuum environment, which is an optical fiber preform or a synthetic quartz blank.

[0003] The deposition mechanism of OVD is thermophoresis, which refers to the phenomenon that particles move from high temperature to low temperature in a gas with a temperature gradient because gas molecules in the higher temperature part collide with particles with higher kinetic energy than gas molecules in the lower temperature part. As the size of optical fiber preforms continues to increase, the reasonable density distribution and overall uniformity of the loose body in the OVD process become increasingly important, so the temperature gradient of the deposition chamber must be strictly controlled.

[0004] The prior art equipment for preparing large-size optical fiber preform rods (outer diameter less than 200 mm) includes a deposition chamber, one side of which is connected to the air supply chamber and is equipped with a blowtorch, and the other side of the deposition chamber is equipped with an exhaust channel. There are upper and lower rotating chucks in the deposition chamber for installing the target rod. In order to increase the deposition rate, multiple blowtorches are generally arranged up and down, and each blowtorch corresponds to a different deposition area on the target rod. The blowtorch or the upper and lower chucks are connected to the upper and lower moving device to achieve oscillating deposition.

[0005] This oscillating deposition method requires high stability of both the individual torches and the deposition environment, otherwise there will be uneven loose bodies. Because each torch is responsible for different deposition areas, once a torch becomes abnormal, the deposition in the area it is responsible for will be different from that in other areas, and other torches cannot make corrections and compensation for the deposition in the area responsible for the abnormal torch.

[0006] When the diameter of the optical fiber preform is less than 200mm, this local unevenness may still be within the allowable range. When the diameter of the optical fiber preform exceeds 200mm, the longer deposition time and larger loose body diameter will significantly increase the probability of burner abnormality, and the unevenness of the loose body will be magnified beyond the allowable range, resulting in serious quality defects and even scrapping of the product. When the optical fiber preform develops in the direction of super-large size, this problem will seriously affect the manufacturing cost of the optical fiber preform.

[0007] In order to ensure the uniformity of deposition, the temperature of the gas sent to different areas in the deposition chamber is regulated in the related technology to make the upper and lower temperature distribution of the entire deposition chamber, especially the powder rod deposition area, more uniform and consistent. The flow rate of the extracted gas is adjusted through the air volume control valve to make the air flow field uniform and smooth, reduce turbulence, and stabilize the air flow field in the deposition area. These technologies can improve the stability of the deposition environment, but fail to provide a solution when the blowtorch monomer is abnormal, and thus cannot avoid the risks mentioned above when preparing oversized optical fiber preforms. Summary of the invention

[0008] The embodiments of the present application provide an optical fiber preform manufacturing device and method to solve the problem in the related art that when oscillating deposition is used, a single blowtorch becomes abnormal or the environment changes, which may cause the local non-uniformity of the optical fiber preform to be amplified, resulting in defects or even scrapping.

[0009] A first aspect of an embodiment of the present application provides a manufacturing device for an optical fiber preform, comprising:

[0010] A deposition chamber, wherein an upper rotating chuck and a lower rotating chuck for clamping and rotating the target rod are arranged in the deposition chamber;

[0011] A blowtorch mechanism, the blowtorch mechanism comprising a blowtorch which reciprocates along the height direction of the deposition chamber to cover all deposition areas of the target rod;

[0012] An exhaust mechanism, the exhaust mechanism comprising a plurality of sub-air ducts arranged opposite to the blowtorch and arranged in sequence along the height direction of the deposition chamber;

[0013] Each of the sub-air ducts is provided with an air volume regulating valve which adjusts its opening according to the height change of the blowtorch.

[0014] In some embodiments: the blowtorch mechanism further comprises a blowtorch group frame, on which a plurality of the blowtorches are arranged in sequence and spaced apart along the height direction of the deposition chamber;

[0015] The number of the sub-air ducts is greater than the number of the blowtorches, and the outlets of the plurality of blowtorches are opposite to the inlets of the sub-air ducts one by one in sequence.

[0016] In some embodiments: a vertical linear module for driving the plurality of the burners to reciprocate along the height direction of the deposition chamber is disposed on the burner group frame;

[0017] The burner group frame is also provided with a transverse linear module for driving the plurality of burners to reciprocate in a direction approaching or away from the target rod.

[0018] In some embodiments: the blowtorch mechanism and the exhaust mechanism are provided in multiple groups, and the multiple groups of the blowtorch mechanism correspond to the multiple groups of the exhaust mechanism one by one;

[0019] A plurality of groups of the blowtorch mechanisms and a plurality of groups of the exhaust mechanisms are circumferentially arranged around the outer circumference of the target rod, and the angles between two adjacent blowtorch mechanisms are the same.

[0020] In some embodiments: it also includes a ring-shaped driving mechanism for driving each of the blowtorch mechanisms to rotate around the target rod and causing two adjacent blowtorch mechanisms to move toward or away from each other along the circumference of the target rod;

[0021] The annular driving mechanism is connected to a diameter measuring sensor for detecting the diameter of the loose body on the target rod, and the diameter measuring sensor is used to control the angle between adjacent blowtorch mechanisms driven by the annular driving mechanism.

[0022] In some embodiments: the blowtorches on each of the blowtorch mechanisms are spaced apart from each other in the height direction of the deposition chamber, and when the blowtorches on each of the blowtorch mechanisms move along the height direction of the deposition chamber for deposition, they maintain a fixed distance in the height direction from the blowtorches on other blowtorch mechanisms.

[0023] In some embodiments: the sub-air duct is in the shape of a prism cone, the inlet area of ​​the sub-air duct is larger than the outlet area, the inlet of the sub-air duct is connected to the deposition chamber, the outlet of the sub-air duct is connected to the exhaust duct through a connecting air duct, and the air volume regulating valve is arranged on the connecting air duct.

[0024] In some embodiments: the blowtorch mechanism is provided with a position sensor for detecting the position height of the blowtorch, and the position sensor is connected to the air volume regulating valve in each of the sub-air ducts;

[0025] The opening degree of the air volume regulating valve in each of the sub-air ducts increases as the height distance between the sub-air duct and the blowtorch gradually decreases.

[0026] A second aspect of the embodiments of the present application provides a method for manufacturing an ultra-large-size optical fiber preform, wherein the method uses the optical fiber preform manufacturing device described in any of the above embodiments, comprising:

[0027] The target rod is mounted on the upper rotating chuck and the lower rotating chuck of the deposition chamber, and the upper rotating chuck and the lower rotating chuck are turned on to drive the target rod to rotate;

[0028] Turn on the air supply mechanism and the air exhaust mechanism to make the wind speed and wind pressure in the deposition chamber reach the preset range;

[0029] The torches of the torch mechanisms are ignited in sequence, so that the raw material gas, fuel gas and inert gas sprayed by the torches are mixed and burned to generate silicon dioxide particles that adhere to the target rod to form a loose body;

[0030] The torches of each torch mechanism start from the starting position one after another, and move along the axial direction of the target rod to all the deposition areas of the loose body at the same speed. When the torch reaches the end position, it turns off or reduces the flame and returns to the starting position;

[0031] During the deposition of the loose body, the opening of each air volume regulating valve of each exhaust mechanism increases as the height distance between each sub-air duct and the corresponding blowtorch gradually decreases, and decreases as the height distance gradually increases;

[0032] The blowtorch continues to spray flames until the target deposition weight is reached, and the blowtorches on each blowtorch mechanism are extinguished in turn. Each sub-air duct gradually reduces the exhaust flow through the air volume regulating valve and makes it consistent, so as to keep the surface temperature of the loose body evenly decreased.

[0033] In some embodiments: the method further comprises:

[0034] During the deposition of the loose body, as the diameter of the loose body gradually increases, the blowtorch of each blowtorch mechanism moves in a direction away from the loose body, and two adjacent blowtorch mechanisms move in a direction away from each other along the circumference of the loose body.

[0035] The beneficial effects of the technical solution provided by this application include:

[0036] The embodiment of the present application provides a manufacturing device and method for an optical fiber preform rod. Since the manufacturing device for the optical fiber preform rod of the present application is provided with a deposition chamber, the deposition chamber is provided with an upper rotating chuck and a lower rotating chuck for clamping and rotating the target rod; a blowtorch mechanism, the blowtorch mechanism includes a blowtorch that reciprocates along the height direction of the deposition chamber to cover all deposition areas of the target rod; an exhaust mechanism, the exhaust mechanism includes a plurality of sub-air ducts arranged opposite to the blowtorch and arranged in sequence along the height direction of the deposition chamber; each sub-air duct is provided with an air volume regulating valve that adjusts its own opening according to the height change of the blowtorch.

[0037] Therefore, the blowtorch mechanism of the optical fiber preform manufacturing device of the present application is provided with a blowtorch that reciprocates along the height direction of the deposition cavity to cover all deposition areas of the target rod, thereby achieving full-process deposition of the target rod. The present application allows each blowtorch to reciprocate along the height direction of the deposition cavity, so that all blowtorches act on all deposition areas of the target rod, and the blowtorches are repeatedly turned back to repeat deposition on all deposition areas of the target rod. Even if there are individual blowtorch failures, the uneven deposition caused by individual differences in the blowtorches can be eliminated. The present application improves the deposition stability of the optical fiber preform, and improves the deposition rate and deposition quality.

[0038] In addition, during the deposition process of the blowtorch of the blowtorch mechanism on the target rod, the sub-air duct of the exhaust mechanism adjusts the exhaust flow rate through the air volume regulating valve according to the position height of the blowtorch in the corresponding blowtorch mechanism. The opening of the air volume regulating valve at the corresponding blowtorch position increases, and the opening of the air volume regulating valve away from the blowtorch decreases, forming a follow-up "exhaust hood". This arrangement can timely extract the dust generated by the corresponding blowtorch but not collected, so that the unattached dust can be effectively extracted in time, avoiding dust agglomeration and deposition on the surface of the loose body again to form defects and scrap, and will not interfere with the flames of other groups of blowtorches, thereby more flexibly regulating the deposition process and ensuring the deposition efficiency of each blowtorch. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 This is a schematic diagram of the structure of an embodiment of the present application;

[0041] Figure 2 A top view of the structure of an embodiment of the present application;

[0042] Figure 3 This is a structural schematic diagram of the blowtorch of the embodiment of the present application moving to the bottom position of the loose body;

[0043] Figure 4 This is a structural schematic diagram of the blowtorch of the embodiment of the present application being moved to the middle position of the loose body;

[0044] Figure 5 This is a structural schematic diagram of the blowtorch of the embodiment of the present application moving to the top position of the loose body;

[0045] Figure 6 This is a schematic diagram of the running trajectory of the blowtorches on the multiple blowtorch mechanisms of an embodiment of the present application.

[0046] Reference numerals:

[0047] 1. Target rod; 2. Loose body; 3. Upper rotating chuck; 4. Lower rotating chuck; 5. Blowtorch; 6. Vertical linear module; 7. Horizontal linear module; 8. Sub-air duct; 9. Connecting air duct; 10. Air volume regulating valve; 11. Exhaust duct. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0049] The embodiments of the present application provide an apparatus and method for manufacturing an optical fiber preform, which can solve the problem in the related art that when using oscillating deposition, a single blowtorch becomes abnormal or the environment changes, which can cause the local non-uniformity of the optical fiber preform to be amplified, resulting in defects or even scrapping.

[0050] See also Figure 1 and Figure 2 As shown, the first aspect of the embodiment of the present application provides a manufacturing device for an optical fiber preform, comprising:

[0051] A deposition chamber is provided with an upper rotating chuck 3 and a lower rotating chuck 4 for clamping and rotating a target rod 1; the upper rotating chuck 3 and the lower rotating chuck 4 are used to clamp the upper and lower ends of the target rod 1, and drive the target rod 1 to rotate in the deposition chamber at a set speed, and the length of the effective deposition area on the target rod 1 is 3500 mm.

[0052] The blowtorch mechanism includes a blowtorch 5 which reciprocates along the height direction of the deposition chamber to cover all deposition areas of the target rod 1; the blowtorch 5 is arranged on the periphery of the target rod 1, and moves up and down along the axial direction of the target rod 1 to spray flames on all deposition areas of the target rod 1, and then the silicon dioxide powder generated by the flame adheres to the surface of the target rod 1 to form a loose body 2.

[0053] The exhaust mechanism includes a plurality of sub-air ducts 8 which are arranged opposite to the blowtorch 5 and are arranged in sequence along the height direction of the deposition chamber; the plurality of sub-air ducts 8 are arranged on the periphery of the target rod 1 and are opposite to the flame nozzle direction of the blowtorch 5 along the axial direction of the target rod 1, so as to timely exhaust the dust generated by the corresponding blowtorch 5 but not deposited.

[0054] Each sub-air duct 8 is provided with an air volume regulating valve 10 that adjusts its opening according to the height change of the blowtorch 5. The opening of the air volume regulating valve 10 in each sub-air duct 8 changes as follows: the closer the height distance of the sub-air duct 8 to the blowtorch 5, the larger the opening of the air volume regulating valve 10 corresponding to the position of the blowtorch 5; the farther the height distance of the sub-air duct 8 from the blowtorch 5, the smaller the opening of the air volume regulating valve 10 corresponding to the position of the blowtorch 5, forming a follow-up "exhaust hood".

[0055] The torch mechanism of the optical fiber preform manufacturing device of the embodiment of the present application is provided with a torch 5 that reciprocates along the height direction of the deposition cavity to cover all deposition areas of the target rod 1, so as to achieve full-process deposition of the target rod 1. The present application allows each torch 5 to reciprocate along the height direction of the deposition cavity, so that all the torches 5 act on all deposition areas of the target rod 1, and the torches 5 return multiple times to repeat deposition on all deposition areas of the target rod 1, so that even if individual torches 5 fail, the uneven deposition caused by individual differences of the torches 5 can be eliminated.

[0056] In addition, when the blowtorch 5 of the blowtorch mechanism deposits on the target rod 1, the sub-air duct 8 of the exhaust mechanism adjusts the exhaust flow rate through the air volume regulating valve 10 according to the position height of the blowtorch 5 in the corresponding blowtorch mechanism. The opening of the air volume regulating valve 10 corresponding to the position of the blowtorch 5 increases, and the opening of the air volume regulating valve far away from the blowtorch 5 decreases, forming a follow-up "exhaust hood".

[0057] This arrangement can timely extract the dust generated by the corresponding blowtorch 5 but not collected, so that the unattached dust can be effectively extracted in time to avoid dust agglomeration and re-deposition on the surface of the loose body 2 to form defects and become scrapped, and will not interfere with the flames of the blowtorches 5 in other queues, thereby more flexibly regulating the deposition process and ensuring the deposition efficiency of each blowtorch 5.

[0058] In some alternative embodiments: See Figure 1 and Figure 2 As shown, the embodiment of the present application provides a manufacturing device for an optical fiber preform rod, the torch mechanism of the manufacturing device further includes a torch group frame (not shown in the figure), and a plurality of torches 5 are arranged in sequence along the height direction of the deposition chamber on the torch group frame. The number of torches 5 on each torch group frame is preferably, but not limited to, four, and the spacing between the four torches 5 along the height direction is 200 mm.

[0059] The number of sub-air ducts 8 on each exhaust mechanism is greater than the number of blowtorches 5 on each blowtorch mechanism, and the number of sub-air ducts 8 is preferably 10-20, the large-diameter ends of the 10-20 sub-air ducts 8 are connected to the deposition chamber, and the small-diameter ends are connected to the connecting air duct 9. When the four blowtorches 5 move up and down along the axis of the target rod 1, the outlets of the four blowtorches 5 are opposite to the inlets of the sub-air ducts 8 one by one in sequence.

[0060] See also Figure 3 As shown, when the four blowtorches 5 move up and down along the axial direction of the target rod 1, when the four blowtorches 5 are located at the bottom of the loose body 2 to deposit the loose body 2, the air volume regulating valves 10 in the multiple sub-air ducts 8 located at the bottom of the loose body 2 among the 10-20 sub-air ducts 8 have the largest opening, and the air volume regulating valves 10 in the remaining multiple sub-air ducts 8 away from the four blowtorches 5 gradually decrease in opening until they are closed, thereby forming a follow-up exhaust capability.

[0061] See also Figure 4 As shown, when the four blowtorches 5 move up and down along the axial direction of the target rod 1, when the four blowtorches 5 are located in the middle of the loose body 2 to deposit the loose body 2, the air volume regulating valves 10 in multiple sub-air ducts 8 located in the middle of the loose body 2 among the 10-20 sub-air ducts 8 have the largest opening, and the air volume regulating valves 10 in the remaining multiple sub-air ducts 8 away from the four blowtorches 5 gradually decrease in opening until they are closed, thereby forming a follow-up exhaust capability.

[0062] See also Figure 5 As shown, when the four blowtorches 5 move up and down along the axial direction of the target rod 1, when the four blowtorches 5 are located at the top of the loose body 2 to deposit the loose body 2, the air volume regulating valves 10 in the multiple sub-air ducts 8 located at the top of the loose body 2 among the 10-20 sub-air ducts 8 have the largest opening, and the air volume regulating valves 10 in the remaining multiple sub-air ducts 8 away from the four blowtorches 5 gradually decrease in opening until they are closed, thereby forming a follow-up exhaust capability.

[0063] In some alternative embodiments: See Figure 1 and Figure 2 As shown, an embodiment of the present application provides a manufacturing device for an optical fiber preform rod, wherein a vertical linear module 6 for driving four blowtorches 5 to reciprocate along the height direction of a deposition chamber is provided on the blowtorch group frame of the manufacturing device, and the travel range of the vertical linear module 6 is greater than the length of an effective deposition area on the target rod 1, so that the four blowtorches 5 can cover all deposition areas of the loose body 2, and the movement direction of the vertical linear module 6 is parallel to the axis of the target rod 1.

[0064] A horizontal linear module 7 is also provided on the burner assembly frame for driving the four burners 5 to reciprocate in a direction approaching or moving away from the target rod 1. The horizontal linear module 7 is located at the bottom of the burner assembly frame and the vertical linear module 6. As the diameter of the loose body 2 on the target rod 1 increases, the burner assembly frame and the vertical linear module 6 move away from the loose body 2 along the length direction of the horizontal linear module 7 to maintain a suitable distance between the burner 5 and the loose body 2. The distance between the burner 5 and the surface of the loose body 2 is set according to the recipe.

[0065] In some alternative embodiments: See Figure 1 and Figure 2 As shown, the embodiment of the present application provides a manufacturing device for an optical fiber preform rod, wherein the torch mechanism and the exhaust mechanism of the manufacturing device are provided with multiple groups, and the torch mechanism and the exhaust mechanism are preferably but not limited to four groups, and the four torch mechanisms correspond to the four exhaust mechanisms one by one. The four torch mechanisms and the four exhaust mechanisms are circumferentially surrounded by the outer periphery of the target rod 1, and the angle α between two adjacent torch mechanisms is the same, and the angle α between two adjacent torch mechanisms is preferably but not limited to 10° to 30°.

[0066] The prior art has only one exhaust chamber in the deposition chamber, so when there are multiple sets of torch mechanisms, it is impossible to take into account the exhaust requirements of multiple deposition routes at different heights and different horizontal positions. The torches 5 of each torch mechanism are affected differently by the exhaust chamber, especially the torches 5 of the edge torch mechanisms are more affected by the exhaust chamber, thus affecting the overall deposition rate and deposition quality.

[0067] The embodiment of the present application has four groups of exhaust mechanisms on the other side of the deposition chamber, and each group of exhaust mechanisms corresponds to a group of blowtorch mechanisms. Each group of blowtorch mechanisms is composed of 10-20 sub-air ducts 8, and the sub-air ducts 8 of each group of exhaust mechanisms are connected to the exhaust duct 11 through independent connecting air ducts 9. An air volume regulating valve 10 is installed on the connecting air duct 9 of the sub-air duct 8, and the air volume regulating valve 10 is used to adjust the flow rate of the extracted gas. When the blowtorch 5 of the blowtorch mechanism group moves up and down, the air volume of the sub-air duct 8 in the corresponding exhaust mechanism is adjusted accordingly through the air volume regulating valve 10, forming a following exhaust mode.

[0068] In some alternative embodiments: See Figure 1 and Figure 2 As shown, the embodiment of the present application provides a manufacturing device for an optical fiber preform, which also includes a ring-shaped driving mechanism (not shown in the figure) that drives each burner mechanism to rotate around the target rod 1 and moves two adjacent burner mechanisms in a direction of approaching or moving away from each other along the circumference of the target rod 1. The projections of the burners 5 on the two adjacent burner mechanisms on the horizontal plane are distributed at a certain angle, forming multiple deposition routes on the surface of the loose body 2, which can reduce the temperature difference between the fire-facing surface and the back-fire surface of the loose body surface (the temperature is less than 10°C), and eliminate the cracking of the oversized loose body 2 caused by the surface temperature difference.

[0069] The annular drive mechanism is connected to a diameter sensor (not shown) for detecting the diameter of the loose body 2 on the target rod 1. The diameter sensor is used to control the angle between adjacent burner mechanisms driven by the annular drive mechanism. The reaction points of the burners 5 on the four burner mechanisms on the loose body 2 are adjusted in position as the diameter of the loose body 2 increases, so as to avoid cracking caused by uneven temperature of the loose body 2.

[0070] The horizontal position of each blowtorch 5 on the four blowtorch mechanisms can be adjusted. The angle formed by each blowtorch 5 on the four blowtorch mechanisms covering the loose body 2 is initially 0-60 degrees. When the outer diameter of the loose body 2 increases, the angle formed by each blowtorch 5 on the four blowtorch mechanisms covering the loose body 2 gradually expands to 120 degrees.

[0071] In the initial stage, the angles between the torches 5 on the four torch mechanisms are small because the diameter of the target rod 1 is relatively small and the inner layer powder needs to be well combined with the target rod 1. Therefore, the angles between the torches 5 on the four torch mechanisms are small, the sprayed flames are concentrated, the temperature is high, and the powder density is high. As the outer diameter of the loose body 2 gradually increases, the surface area of ​​the loose body 2 increases. In addition, the rotation speed of the target rod 1 decreases, and the surface temperature difference of the loose body 2 increases. Therefore, the angles between the torches 5 on the four torch mechanisms are increased to appropriately disperse the sprayed flames, which helps to maintain the uniform temperature of the loose body 2.

[0072] In some alternative embodiments: See Figure 1 and Figure 2 As shown, an embodiment of the present application provides a manufacturing device for an optical fiber preform rod, in which the blowtorches 5 on each blowtorch mechanism of the manufacturing device are arranged in sequence and spaced apart from each other along the height direction of a deposition chamber, and when the blowtorches 5 on each blowtorch mechanism are moved along the height direction of the deposition chamber for deposition, they maintain a fixed distance in the height direction from the blowtorches 5 on other blowtorch mechanisms.

[0073] The blowtorches 5 on different blowtorch mechanisms in the embodiment of the present application start out successively in the vertical direction. By adjusting the moving speed of the blowtorch 5 during deposition and the moving speed during return, a suitable temperature difference (±50°C) can be formed in the axial direction of the loose body 2, which is beneficial for the dust to adhere to the surface of the loose body 2 under the action of thermophoresis, thereby achieving a higher collection efficiency than the oscillation type.

[0074] like Figure 6 As shown, the torches 5 on the four torch mechanisms start in the vertical direction one after another, depositing silicon dioxide powder layer by layer on the surface of the loose body 2 to form the loose body of the optical fiber preform. In the full-process deposition method, the torches 5 do not participate in the deposition during the return process, and the number of effective torches is related to the ratio of the deposition speed to the return speed. Using slow deposition and fast return will effectively increase the deposition rate.

[0075] When the length of the torch 5 is ignored, the utilization rate of the torch 5 is shown in the following table. Taking the deposition rate and the collection efficiency into consideration, the deposition moving speed range of the torch 5 is determined to be 100-400 mm / min, and the return speed range of the torch 5 is determined to be 1000-3000 mm / min.

[0076] Serial number Deposition speed (mm / min) Return speed (mm / min) Rate Ratio Blowtorch utilization 1 100 1000 10 91％ 2 200 1000 5 83％ 3 100 2000 20 95％ 4 200 2000 10 91％

[0077] See also Figure 6 As shown, Figure 6 The horizontal axis is the deposition time t of the burners 5 on the four burner mechanisms, and the vertical axis is the moving height h of the burners 5 on the four burner mechanisms. The working order of the burners 5 on the four burner mechanisms of the present application embodiment is as follows:

[0078] First, the blowtorch 5 on the first group of blowtorch mechanisms first moves upward from the bottom of the loose body 2 at a speed of 100-400 mm / min to deposit on the surface of the loose body 2, until the blowtorch 5 on the first group of blowtorch mechanisms moves to the top of the loose body 2, and then quickly returns to the bottom of the loose body 2 at a speed of 1000-3000 mm / min.

[0079] Secondly, after the blowtorches 5 on the first group of blowtorch mechanisms leave the bottom of the loose body 2, the blowtorches 5 on the second group of blowtorch mechanisms move upward from the bottom of the loose body 2 again at a speed of 100-400mm / min to deposit on the surface of the loose body 2, until the blowtorches 5 on the second group of blowtorch mechanisms move to the top of the loose body 2, and then quickly return to the bottom of the loose body 2 at a speed of 1000-3000mm / min.

[0080] Then, after the blowtorches 5 on the second group of blowtorch mechanisms leave the bottom of the loose body 2, the blowtorches 5 on the third group of blowtorch mechanisms move upward from the bottom of the loose body 2 again at a speed of 100-400mm / min to deposit on the surface of the loose body 2, until the blowtorches 5 on the third group of blowtorch mechanisms move to the top of the loose body 2, and then quickly return to the bottom of the loose body 2 at a speed of 1000-3000mm / min.

[0081] Finally, after the blowtorches 5 on the third group of blowtorch mechanisms leave the bottom of the loose body 2, the blowtorches 5 on the fourth group of blowtorch mechanisms move upward from the bottom of the loose body 2 again at a speed of 100-400mm / min to deposit on the surface of the loose body 2, until the blowtorches 5 on the fourth group of blowtorch mechanisms move to the top of the loose body 2, and then quickly return to the bottom of the loose body 2 at a speed of 1000-3000mm / min.

[0082] The working order of the above four groups of blowtorch mechanisms is cycled until the deposition weight of the optical fiber preform reaches a predetermined value (±1kg). The blowtorch 5 returns to the deposition starting point and no more raw gas is introduced. Hydrogen and oxygen are retained and the surface of the loose body 2 is heat treated according to the flow rate set in the formula. Finally, the gas is cut off according to the formula setting to complete the deposition.

[0083] In some alternative embodiments: See Figure 1 and Figure 2 As shown, the embodiment of the present application provides a manufacturing device for an optical fiber preform, wherein the sub-air duct 8 of the manufacturing device is in the shape of a prism cone, the inlet area of ​​the sub-air duct 8 is larger than the outlet area, and the inlet of the sub-air duct 8 is connected to the deposition cavity. The outlet of the sub-air duct 8 is connected to the exhaust duct 11 through the connecting air duct 9, and the air volume regulating valve 10 is arranged on the connecting air duct 9.

[0084] The blowtorch mechanism is provided with a position sensor (not shown) for detecting the position height of the blowtorch 5, and the position sensor is connected to the air volume regulating valve 10 in each sub-air duct 8. The opening of the air volume regulating valve 10 in each sub-air duct 8 increases as the height distance between the sub-air duct 8 and the blowtorch 5 gradually decreases. That is, the air volume regulating valve 10 in the sub-air duct 8 that is closer to the blowtorch 5 has the largest opening, and the air volume regulating valve 10 in the sub-air duct 8 that is far away from the blowtorch 5 gradually decreases until it is closed.

[0085] See also Figures 1 to 6 As shown, a second aspect of the embodiment of the present application provides a method for manufacturing an ultra-large-size optical fiber preform, wherein the method uses the optical fiber preform manufacturing device described in any of the above embodiments, and comprises:

[0086] Step 1: Mount the target rod 1 on the upper rotating chuck 3 and the lower rotating chuck 4 of the deposition chamber, and start the upper rotating chuck 3 and the lower rotating chuck 4 to drive the target rod 1 to rotate.

[0087] Step 2: Turn on the air supply mechanism and the air exhaust mechanism to make the wind speed and wind pressure in the deposition chamber reach a preset range.

[0088] Step 3, ignite the torches 5 of the torch mechanisms in sequence, so that the raw material gas, fuel gas and inert gas sprayed by the torches 5 are mixed and burned to generate silicon dioxide particles attached to the target rod 1 to form a loose body 2.

[0089] Step 4: The blowtorches 5 of each blowtorch mechanism start from the starting position one after another, and move along the axial direction of the target rod 1 to all deposition areas of the loose body 2 at the same speed. When the blowtorches 5 reach the end position, they are turned off or the flame is reduced and then returned to the starting position.

[0090] Step 5: During the deposition of the loose body 2, the opening of each air volume regulating valve 10 of each exhaust mechanism increases as the height distance between each sub-air duct 8 and the corresponding blowtorch 5 gradually decreases, and decreases as the height distance gradually increases.

[0091] Step 6: During the deposition of the loose body 2 , as the diameter of the loose body 2 gradually increases, the blowtorch 5 of each blowtorch mechanism moves in a direction away from the loose body 2 , and two adjacent blowtorch mechanisms move in a direction away from each other along the circumference of the loose body 2 .

[0092] Step 7, the blowtorch 5 continues to spray flame until the target deposition weight is reached, the blowtorches 5 on each blowtorch mechanism are turned off in turn, and each sub-air duct 8 gradually reduces the exhaust flow rate through the air volume regulating valve 10 and makes it consistent, so as to keep the surface temperature of the loose body 2 evenly decreased.

[0093] How it works

[0094] The embodiment of the present application provides a manufacturing device and method for an optical fiber preform rod. Since the manufacturing device for the optical fiber preform rod of the present application is provided with a deposition chamber, the deposition chamber is provided with an upper rotating chuck 3 and a lower rotating chuck 4 for clamping and rotating a target rod 1; a blowtorch mechanism, the blowtorch mechanism includes a blowtorch 5 that reciprocates along the height direction of the deposition chamber to cover all deposition areas of the target rod 1; an exhaust mechanism, the exhaust mechanism includes a plurality of sub-air ducts 8 that are arranged opposite to the blowtorch 5 and arranged in sequence along the height direction of the deposition chamber; each sub-air duct 8 is provided with an air volume regulating valve 10 that adjusts its own opening according to the height change of the blowtorch 5.

[0095] Therefore, the torch mechanism of the optical fiber preform manufacturing device of the present application is provided with a torch 5 that moves back and forth along the height direction of the deposition cavity to cover all deposition areas of the target rod 1, so as to achieve full-process deposition of the target rod 1. The present application allows each torch 5 to move back and forth along the height direction of the deposition cavity, so that all torches 5 act on all deposition areas of the target rod 1, and the torches 5 return multiple times to repeat deposition on all deposition areas of the target rod 1, so that even if there is a failure of an individual torch 5, the uneven deposition caused by the individual differences of the torches 5 can be eliminated. The present application improves the deposition stability of the optical fiber preform, and improves the deposition rate and deposition quality.

[0096] In addition, during the deposition process of the blowtorch 5 of the blowtorch mechanism on the target rod 1, the sub-air duct 8 of the exhaust mechanism adjusts the exhaust flow rate through the air volume regulating valve 10 according to the position height of the blowtorch 5 in the corresponding blowtorch mechanism. The opening of the air volume regulating valve 10 corresponding to the position of the blowtorch 5 increases, and the opening of the air volume regulating valve 10 away from the blowtorch 5 decreases, forming a follow-up "exhaust hood". This arrangement can timely extract the dust generated but not collected by the corresponding blowtorch 5, so that the unattached dust can be effectively extracted in time, avoiding dust agglomeration and deposition on the surface of the loose body 2 again to form defects and scrap, and will not interfere with the flames of other groups of blowtorches 5, so as to more flexibly regulate the deposition process and ensure the deposition efficiency of each blowtorch 5.

[0097] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0098] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0099] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A manufacturing device for an optical fiber preform, characterized in that: include: A deposition chamber, wherein an upper rotating chuck (3) and a lower rotating chuck (4) for clamping and rotating the target rod (1) are arranged in the deposition chamber; A blowtorch mechanism, the blowtorch mechanism comprising a blowtorch (5) which reciprocates along the height direction of the deposition chamber to cover all deposition areas of the target rod (1); An air extraction mechanism, the air extraction mechanism comprising a plurality of sub-air ducts (8) arranged opposite to the blowtorch (5) and arranged in sequence along the height direction of the deposition chamber; Each of the sub-air ducts (8) is provided with an air volume regulating valve (10) which adjusts its opening according to the height change of the blowtorch (5).

2. The optical fiber preform manufacturing device according to claim 1, characterized in that: The burner mechanism further comprises a burner assembly frame, on which a plurality of burners (5) are arranged in sequence and spaced apart along the height direction of the deposition chamber; The number of the sub-air ducts (8) is greater than the number of the blowtorches (5), and the outlets of the plurality of blowtorches (5) are opposite to the inlets of the sub-air ducts (8) in sequence.

3. The manufacturing device of an optical fiber preform according to claim 2, characterized in that: The burner group frame is provided with a vertical linear module (6) for driving the plurality of burners (5) to reciprocate along the height direction of the deposition chamber; The burner group frame is also provided with a transverse linear module (7) for driving the plurality of burners (5) to reciprocate in a direction approaching or moving away from the target rod (1).

4. The optical fiber preform manufacturing device according to any one of claims 1 to 3, characterized in that: The blowtorch mechanism and the exhaust mechanism are provided in multiple groups, and the multiple groups of the blowtorch mechanism correspond to the multiple groups of the exhaust mechanism one by one; A plurality of groups of the blowtorch mechanisms and a plurality of groups of the exhaust mechanisms are circumferentially arranged around the outer circumference of the target rod (1), and the angles between two adjacent blowtorch mechanisms are the same.

5. The manufacturing device of an optical fiber preform according to claim 4, characterized in that: It also includes an annular driving mechanism for driving each of the burner mechanisms to rotate around the target rod (1) and causing two adjacent burner mechanisms to move along the circumference of the target rod (1) in a direction approaching or moving away from each other; The annular driving mechanism is connected to a diameter measuring sensor for detecting the diameter of the loose body (2) on the target rod (1), and the diameter measuring sensor is used to control the size of the angle between adjacent burner mechanisms driven by the annular driving mechanism.

6. The manufacturing device for an optical fiber preform according to claim 4, characterized in that: The blowtorches (5) on each of the blowtorch mechanisms are arranged in sequence and spaced apart from each other along the height direction of the deposition chamber. When the blowtorches (5) on each of the blowtorch mechanisms are moved along the height direction of the deposition chamber for deposition, they maintain a fixed distance from the blowtorches (5) on other blowtorch mechanisms in the height direction.

7. The manufacturing device for an optical fiber preform according to claim 4, characterized in that: The sub-air duct (8) is in the shape of a prism cone, the inlet area of ​​the sub-air duct (8) is larger than the outlet area, the inlet of the sub-air duct (8) is connected to the deposition chamber, the outlet of the sub-air duct (8) is connected to the exhaust duct (11) via the connecting air duct (9), and the air volume regulating valve (10) is arranged on the connecting air duct (9).

8. The optical fiber preform manufacturing device according to claim 1, characterized in that: The blowtorch mechanism is provided with a position sensor for detecting the position height of the blowtorch, and the position sensor is connected to an air volume regulating valve (10) in each of the sub-air ducts; The opening degree of the air volume regulating valve (10) in each of the sub-air ducts (8) increases as the height distance between the sub-air duct (8) and the blowtorch (5) gradually decreases.

9. A method for manufacturing an ultra-large optical fiber preform, characterized in that: The method uses the optical fiber preform manufacturing device according to any one of claims 1 to 8, comprising: The target rod (1) is mounted on an upper rotating chuck (3) and a lower rotating chuck (4) of a deposition chamber, and the upper rotating chuck (3) and the lower rotating chuck (4) are turned on to drive the target rod (1) to rotate; Turn on the air supply mechanism and the air exhaust mechanism to make the wind speed and wind pressure in the deposition chamber reach the preset range; The burners (5) of the burner mechanisms are sequentially ignited, so that the raw material gas, fuel gas and inert gas sprayed by the burners (5) are mixed and burned to generate silicon dioxide particles that adhere to the target rod (1) to form a loose body (2); The blowtorches (5) of each blowtorch mechanism start from the starting position one after another, move along the axial direction of the target rod (1) at the same speed to all deposition areas of the loose body (2), and when the blowtorches (5) reach the end position, they are turned off or the flame is reduced and then they return to the starting position; During the deposition of the loose body (2), the opening of each air volume regulating valve (10) of each exhaust mechanism increases as the height distance between each sub-air duct (8) and the corresponding blowtorch (5) gradually decreases, and decreases as the height distance gradually increases; The blowtorch (5) continues to spray flames until the target deposition weight is reached, and the blowtorches (5) on each blowtorch mechanism are extinguished in turn. Each sub-air duct (8) gradually reduces the exhaust flow rate through the air volume regulating valve (10) and makes it consistent, so as to keep the surface temperature of the loose body (2) evenly decreased.

10. The method for manufacturing an ultra-large optical fiber preform according to claim 9, characterized in that: The method further comprises: During the deposition of the loose body (2), as the diameter of the loose body (2) gradually increases, the blowtorch (5) of each blowtorch mechanism moves in a direction away from the loose body (2), and two adjacent blowtorch mechanisms move in a direction away from each other along the circumference of the loose body (2).

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