CN213266281U - Core rod preparation device for large-size optical fiber perform - Google Patents

Abstract

The utility model provides a core rod preparation device for a large-size optical fiber preform rod, which relates to the technical field of optical fiber manufacturing equipment and comprises a deposition cavity, wherein the top of the deposition cavity is provided with a suspender, and a seed rod with the diameter of 40-45mm is arranged below the suspender; a core layer blast lamp, a first cladding layer blast lamp and a second cladding layer blast lamp are arranged in the deposition chamber from bottom to top; when the deposition is started, the distances among the axes of the core layer blast lamp, the first cladding layer blast lamp, the second cladding layer blast lamp and the seed rod in the X-axis direction are respectively 20-60mm, 80-120mm and 140-160 mm; in the Y-axis direction, the distances among the axes of the core layer blast lamp, the first cladding blast lamp, the second cladding blast lamp and the seed rod are all-0.5-0.5 mm; in the Z-axis direction, the intersection points of the central lines of the core layer blowtorch, the first cladding blowtorch and the second cladding blowtorch and the axis of the seed rod are respectively higher than the zero point of the seed rod by 5-15mm, 120-140mm and 220-240 mm.

Description

Core rod preparation device for large-size optical fiber perform

Technical Field

The utility model relates to an optical fiber manufacturing equipment technical field especially relates to a plug preparation facilities for jumbo size optical fiber perform.

Background

With the development of the optical fiber communication industry, the market competition is more and more intense, and the cost determines whether an enterprise is competitive or not to a certain extent. The prefabricated rod is used as a front-end product of the optical fiber, the manufacturing cost of the prefabricated rod directly influences the cost of the optical fiber, the improvement of the production efficiency of the optical fiber prefabricated rod is an effective means for reducing the cost, on one hand, the deposition rate of the optical rod can be improved, and on the other hand, the size of the optical rod is increased.

At present, the optical fiber preform is usually manufactured by VAD, OVD, MCVD, PCVD and other processes, and in order to improve productivity and production efficiency, a two-step method is usually adopted: the core rod (including core layer and cladding layer) is prepared by adopting MCVD, PCVD, VAD and OVD processes, and the outer cladding layer is completed by adopting OVD process or sleeve mode. For the two-step process, the geometric dimension of the core rod determines the dimension of the finished optical fiber preform, wherein the D/D (i.e. the core-spun ratio) of the core rod is a key index related to the product, too large D/D reduces the production efficiency of the product, and too low D/D affects the transmission characteristics of the optical fiber. When a large-size core rod is prepared, the size of the core layer is correspondingly increased, and the D/D of the core rod is larger.

The D/D of the core rod manufactured by the Korean equipment and the American equipment imported at home at present is about 3.8-4.2, the size of the final finished optical fiber preform is about 125mm-150mm by OVD deposition of the outer cladding, and the production efficiency is relatively low even though the size of the finished optical fiber preform is changed by changing the outer diameter of the drawn core rod. Therefore, the production efficiency needs to be improved by preparing the core rod with large size and small D/D on the basis of meeting the transmission performance of the optical fiber.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a plug preparation facilities for jumbo size optical fiber perform, it is through using jumbo size seed stick, and a sandwich layer blowtorch and two covering blowtorches of cooperation deposit out the loose body optical wand in big core footpath more easily, reduces the core-spun ratio D/D of plug, improves the production efficiency of plug.

The above technical purpose of the present invention can be achieved by the following technical solutions:

a core rod preparation device for a large-size optical fiber preform rod comprises a deposition device and a sintering device, wherein the deposition device comprises a deposition cavity, a vertically arranged hanging rod is arranged at the top of the deposition cavity, and the upper end of the hanging rod is connected with a driving device which drives the hanging rod to rotate around the axis of the hanging rod and move up and down along the vertical direction; a seed rod coaxial with the suspender is arranged below the suspender, and the diameter of the seed rod is 40-45 mm; a core layer blast lamp, a first cladding layer blast lamp and a second cladding layer blast lamp are sequentially arranged in the deposition cavity from bottom to top, the included angle between the axis of the core layer blast lamp and the axis of the seed rod is theta 1, the included angle between the axis of the first cladding layer blast lamp and the axis of the seed rod is theta 2, the included angle between the axis of the second cladding layer blast lamp and the axis of the seed rod is theta 3, theta 1 is 36-40 degrees, theta 2 is 47-51 degrees, and theta 3 is 55-60 degrees; when the deposition is started, in the X-axis direction, the distance between the core layer blowtorch and the axis of the seed rod is 20-60mm, the distance between the first cladding layer blowtorch and the axis of the seed rod is 80-120mm, and the distance between the second cladding layer blowtorch and the axis of the seed rod is 140-160 mm; in the Y-axis direction, the distances among the core layer blowtorch, the first cladding blowtorch, the second cladding blowtorch and the axis of the seed rod are all-0.5-0.5 mm; in the Z-axis direction, the intersection point of the central line of the core layer blast lamp and the axis of the seed rod is 5-15mm higher than the zero point of the seed rod, the intersection point of the central line of the first cladding blast lamp and the axis of the seed rod is 140mm higher than the zero point of the seed rod, and the intersection point of the central line of the second cladding blast lamp and the axis of the seed rod is 240mm higher than the zero point of the seed rod, namely 220 mm.

Through adopting above-mentioned technical scheme, in the deposit chamber, install the seed stick on the jib rotatory, the core layer blowtorch is used for the deposit of loose body core layer to control core layer size and production speed, first cladding blowtorch and second cladding blowtorch are used for the deposit of loose body cladding, and the jib upwards promotes along the axial along with the deposit, reaches and sets for deposit length, and the deposit is ended, and the loose body optical wand after will cooling is sent into sintering device and is dehydrated the sintering. The large-size seed rod with the diameter of 40-45mm is selected to facilitate the deposition of the core layer with larger size, and the core layer torch is designed to be suitable for the deposition of the large core diameter by using three torch forms including the core layer torch, the first cladding torch and the second cladding torch. The positions of the core layer blowtorch, the first cladding blowtorch and the second cladding blowtorch are very critical, and the deposition efficiency and the uniformity of the loose body light bar can be directly influenced. The angles and the positions of the core layer blast lamp, the first cladding blast lamp and the second cladding blast lamp are determined by taking the seed rod and the axis thereof at the beginning of deposition as reference, the weight of the prepared loose body optical rod can be improved by 50 percent, the diameter of the deposited loose body optical rod can reach more than 230mm, the length of the deposited loose body optical rod reaches 1300mm-1400mm, the core-spun ratio D/D is reduced to 2.5-3.5, and the corresponding capacity of each kilogram of core rods is improved by about 50 percent.

Further, the sintering device comprises a sintering furnace, wherein a vertically arranged furnace core pipe is arranged in the sintering furnace, and the inner diameter of the furnace core pipe is 260-280 mm.

By adopting the technical scheme, the loose body light rod enters the furnace core pipe for sintering, and the diameter of the deposited loose body light rod is increased, so that the inner diameter of the furnace core pipe is set to be 260-280mm, the furnace core pipe can be suitable for sintering large-size loose body light rods, the production requirement is met, and the application range is widened.

Furthermore, a dehydration zone and a sintering zone positioned below the dehydration zone are arranged in the sintering furnace, the temperature of the dehydration zone is 1100-1200 ℃, and the temperature of the sintering zone is 1500-1550 ℃.

By adopting the technical scheme, the dehydration and the sintering are integrated on one sintering furnace, the loose body light bar moves from top to bottom in the furnace core tube, the loose body light bar is dehydrated through the dehydration area and then enters the sintering area for sintering, and the sintered mother bar is lifted out of the furnace core tube after the sintering is finished. The dehydration zone is arranged above the sintering zone, the temperature of the dehydration zone is set to be 1100-1200 ℃, and the temperature of the sintering zone is set to be 1500-1550 ℃, so that the phenomenon that the dehydration temperature is too high to easily cause the density to become large is avoided, the phenomenon that the sintering temperature is too low to enable the loose body optical rod to be vitrified by sintering is also avoided, the sintered mother rod is prevented from generating bubbles, and the dehydration sintering effect and the product quality are ensured.

Further, the bottom of the furnace core pipe is provided with an air inlet, chlorine and helium are introduced into the air inlet, the flow rate of the chlorine is 0.6-1.5SLM, and the flow rate of the helium is 20-30 SLM.

By adopting the technical scheme, the chlorine assists in dehydrating the loose body optical rod, and the helium has high heat conductivity coefficient, so that the temperature of the sintering furnace is more quickly and uniformly transferred into the furnace core pipe, and the dehydrating and sintering effect on the loose body optical rod is improved. The flow control of the chlorine and the helium avoids the condition that the using effect cannot be achieved due to the small amount of the chlorine and the helium, and avoids the condition that the chlorine and the helium are too much and are easy to waste.

Furthermore, the core layer blowtorch is provided with eight annular core layer nozzles which are concentrically arranged, and each core layer nozzle simultaneously sprays hydrogen, silicon tetrachloride, germanium tetrachloride, hydrogen, argon, oxygen, argon, hydrogen, argon and oxygen from inside to outside.

Through adopting above-mentioned technical scheme, eight sandwich layer spouts of sandwich layer blowtorch design, every sandwich layer spout sprays hydrogen + silicon tetrachloride + germanium tetrachloride, hydrogen, argon gas, oxygen, argon gas, hydrogen, argon gas, oxygen respectively simultaneously from inside to outside, designs the injection structure of sandwich layer blowtorch like this, and the material that makes the sandwich layer blowtorch erupt can be applicable to the deposit in big core footpath, guarantees the quality of sedimentary loose body optical wand.

Furthermore, the first cladding blowtorch and the second cladding blowtorch are provided with ten annular cladding nozzles which are concentrically arranged, and each cladding nozzle simultaneously sprays hydrogen plus silicon tetrachloride, hydrogen, argon, oxygen, argon and hydrogen respectively from inside to outside.

Through adopting above-mentioned technical scheme, first cladding blowtorch and second cladding blowtorch all set up the cladding spout that is a concentric setting, from inside to outside every cladding spout respectively spray hydrogen + silicon tetrachloride simultaneously, hydrogen, argon gas, oxygen, argon gas, hydrogen, argon gas, hydrogen, design the injection structure of first cladding blowtorch and second cladding blowtorch like this, the material that makes first cladding blowtorch and second cladding blowtorch erupt can be applicable to the deposit of big core footpath surrounding layer, guarantee the quality of sedimentary loose body optical wand.

Furthermore, a waste gas discharge pipe communicated with the side wall of the deposition cavity is arranged on the side wall of the deposition cavity, a sealing cover is arranged at the top of the furnace core pipe, an exhaust pipe communicated with the side wall of the sealing cover is arranged on the side wall of the sealing cover, and the waste gas discharge pipe and the exhaust pipe are connected with a waste gas station.

Through adopting above-mentioned technical scheme, the loose body light stick of raw materials deposit that deposit intracavity sandwich layer blowtorch, first cladding blowtorch and second cladding blowtorch sprayed, view exhaust emission pipe such as the dust of non-deposit, waste gas get into the exhaust station, and chlorine and helium in the stove core pipe get into the exhaust station from the blast pipe, and the exhaust station is unified to handling and emission such as waste gas, dust, reduces the pollution to the environment.

Further, the annealing furnace is further included, the temperature of the annealing furnace is 1100 ℃, and the annealing time is more than 15 h.

By adopting the technical scheme, the sintered mother rod is placed in an annealing furnace and annealed for more than 15 hours at 1100 ℃, residual stress in the mother rod is eliminated, the size of the mother rod is stabilized, deformation and cracks are reduced, so that the mother rod is stretched into the core rod with the required outer diameter size, and the quality of the core rod is ensured.

To sum up, the utility model discloses following beneficial effect has:

1. by selecting large-size seed rods, using a core layer blast lamp, a first cladding blast lamp and a second cladding blast lamp in a matching way and designing the angles and the positions of the core layer blast lamp, the first cladding blast lamp and the second cladding blast lamp, loose light rods with large core diameters are deposited more easily;

2. the weight of the loose body light rod prepared by using the core layer blowtorch, the first cladding blowtorch and the second cladding blowtorch can be improved by 50 percent;

3. the diameter of the light rod of the sedimentary loose body can reach more than 230mm, and the core-spun ratio D/D is reduced to 2.5-3.5, so that the corresponding capacity of each kilogram of core rod is improved by about 50 percent.

Drawings

FIG. 1 is a schematic view showing the overall construction of a core rod fabricating apparatus for a large-sized optical fiber preform;

FIG. 2 is a view showing the positions of a core burner, a first cladding burner and a second cladding burner in a core rod fabricating apparatus for a large-sized optical fiber preform, from a front view in an X-Z plane;

FIG. 3 is a view showing the positions of a core burner, a first cladding burner and a second cladding burner in a core rod fabricating apparatus for a large-sized optical fiber preform, from a front view in a Y-Z plane;

FIG. 4 is a schematic diagram of a core nozzle configuration of a core burner;

fig. 5 is a schematic view of a cladding orifice structure of the first cladding torch.

In the figure, 1, a deposition apparatus; 11. a deposition chamber; 12. a boom; 13. a seed stick; 14. an exhaust gas discharge pipe; 2. a sintering device; 21. sintering furnace; 211. a dewatering zone; 212. a sintering zone; 22. a furnace core pipe; 221. an air inlet; 222. sealing the cover; 223. an exhaust pipe; 3. a waste gas station; 4. an annealing furnace; 5. a core layer blowtorch; 51. a core layer nozzle; 6. a first cladding torch; 7. a second cladding torch; 8. a cladding spout; 9. loose body light bar.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

The first embodiment is as follows:

a core rod preparation device for a large-size optical fiber preform is shown in figure 1 and comprises a deposition device 1, a sintering device 2, an annealing furnace 4 and a waste gas station 3, wherein a loose body optical rod 9 is deposited in the deposition device 1, the deposited loose body optical rod 9 enters the sintering device 2 to be dehydrated and sintered into a transparent mother rod, the transparent mother rod enters the annealing furnace 4 to be annealed for more than 15 hours at 1100 ℃, internal residual stress is eliminated, and the mother rod is stretched into the required outer diameter size, namely the core rod. Wherein, the waste gas, dust and the like generated in the deposition device 1 and the sintering device 2 are all discharged after being uniformly processed by the waste gas station 3.

As shown in fig. 1, the deposition apparatus 1 includes a deposition chamber 11, a vertically disposed suspension rod 12 is disposed at the top of the deposition chamber 11, and a driving device for driving the suspension rod 12 to rotate around its axis and move up and down along the vertical direction is connected to the upper end of the suspension rod 12, wherein the driving device is the same as the prior art and is not described in detail, and is not shown in the drawings. A seed rod 13 is arranged under the suspension rod 12 and is coaxial with the suspension rod, the diameter of the seed rod 13 is 40-45mm, and thus the seed rod 13 with the large size is selected to facilitate the deposition of a core layer with the larger size. In this embodiment, the diameter of the seed rod 13 is 40 mm.

As shown in fig. 1, a core layer torch 5, a first cladding torch 6 and a second cladding torch 7 are further arranged in the deposition chamber 11, the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 are located on the same side and are all obliquely arranged, and one end of the core layer torch 5, the one end of the first cladding torch 6 and the one end of the second cladding torch 7, which are close to the seed rod 13, are higher. The core layer torch 5, the first cladding torch 6 and the second cladding torch 7 are arranged, and three torch types are arranged, so that the large-size loose body light bar 9 can be deposited more easily, but the positions of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 are very critical, and the deposition efficiency and the uniformity of the loose body light bar 9 can be directly influenced.

Before depositing the loose light bar 9, the positions of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 need to be determined, and the inclination angles of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 and the positions of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 on the X axis, the Y axis and the Z axis need to be determined. As shown in fig. 2, the included angle between the axis of the core layer torch 5 and the axis of the seed rod 13 is θ 1, and θ 1 is 36-40 °; the included angle between the axis of the first cladding blowtorch 6 and the axis of the seed rod 13 is theta 2, and the theta 2 is 47-51 degrees; the included angle between the axis of the second cladding blowtorch 7 and the axis of the seed rod 13 is theta 3, and the theta 3 is 55-60 degrees. In the present embodiment, θ 1 is 36 °, θ 2 is 49 °, and θ 3 is 60 °.

As shown in fig. 2 and 3, at the start of deposition, the distance between the center of the burner of the core burner 5 and the axis of the seed rod 13 in the X-axis direction was X1, and X1-60 mm, the distance between the center of the burner of the first cladding burner 6 and the axis of the seed rod 13 was X2, and X2-120 mm, the distance between the center of the burner of the second cladding burner 7 and the axis of the seed rod 13 was X3, and X3-140-160 mm. Distances Y1, Y2 and Y3 between the axes of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 and the axis of the seed rod 13 in the Y-axis direction are all-0.5-0.5 mm, that is, deviations of ± 0.5mm can exist in the Y-axis direction between the axes of the core layer torch 5, the first cladding torch 6 and the second cladding torch 7 and the axis of the seed rod 13, and since values of Y1, Y2 and Y3 are small and cannot be clearly shown in the drawing, Y1, Y2 and Y3 are not shown in the drawing. In the Z-axis direction, the distance from the intersection point of the central line of the core layer blast lamp 5 and the axis of the seed rod 13 to the zero point of the seed rod 13 is Z1, and Z1 is 5-15mm, the distance from the intersection point of the central line of the first cladding blast lamp 6 and the axis of the seed rod 13 to the zero point of the seed rod 13 is Z2, and Z2 is 120-240 mm, the distance from the intersection point of the central line of the second cladding blast lamp 7 and the axis of the seed rod 13 to the zero point of the seed rod 13 is Z3, and Z3 is 220-240 mm.

As shown in fig. 2 and 3, in the present embodiment, the distance X1 between the center of the burner of the core burner 5 and the axis of the seed rod 13 in the X-axis direction is 20mm, the distance Y1 between the axis of the core burner 5 and the axis of the seed rod 13 in the Y-axis direction is-0.5 mm, and the distance Z1 between the center line of the core burner 5 and the axis of the seed rod 13 in the Z-axis direction is 5mm, which is higher than the zero point of the seed rod 13. The distance X2 between the center of the lamp holder of the first cladding torch 6 and the axis of the seed rod 13 in the X-axis direction is 100mm, the distance Y2 between the axis of the first cladding torch 6 and the axis of the seed rod 13 in the Y-axis direction is 0mm, and the distance Z2 between the intersection point of the center line of the first cladding torch 6 and the axis of the seed rod 13 in the Z-axis direction is 130mm, which is higher than the zero point of the seed rod 13. The distance X3 between the center of the lamp socket of the second cladding torch 7 and the axis of the seed rod 13 in the X-axis direction is 160mm, the distance Y3 between the axis of the second cladding torch 7 and the axis of the seed rod 13 in the Y-axis direction is 0.5mm, and the distance Z3 between the intersection point of the center line of the second cladding torch 7 and the axis of the seed rod 13 in the Z-axis direction is 240mm, which is higher than the zero point of the seed rod 13.

As shown in fig. 2 and 3, when determining the positions of the three torches (the core torch 5, the first cladding torch 6, and the second cladding torch 7 are collectively referred to as the same below), the zero point (the lowest point) of the seed rod 13 is used as a base point, the intersection points of the axes of the three torches and the axis of the seed rod 13 are found along the Z axis by 5mm, 130mm, and 240mm, the axes of the three torches are found from the three intersection points, respectively, and the included angles between the axes and the axis of the seed rod 13 are θ 1 ═ 36 °, θ 2 ═ 49 °, and θ 3 ═ 60 °, and then the center position of the torch mouth can be determined by the distances between the axes and the axis of the seed rod 13 being 20mm, 100mm, and 160mm, respectively, and finally, the axis of the torch and the axis of the seed rod 13 coincide with each other on the Y axis, and the deviation of the torch axis and the axis of the seed rod can be ± 0.5mm on the Y. The position of the core layer blast lamp 5, the relative seed rod 13 of first cladding blast lamp 6 and second cladding blast lamp 7 has been confirmed, the relative position between core layer blast lamp 5, first cladding blast lamp 6 and the second cladding blast lamp 7 has been confirmed promptly, both avoided the core layer blast lamp 5, the interference between the too close meeting of distance can exist flame between first cladding blast lamp 6 and the second cladding blast lamp 7, it is inhomogeneous also to avoid the distance to cause density too far away, produce stress easily and cause loose body to ftracture.

As shown in fig. 4, the core layer torch 5 is provided with eight core layer nozzles 51 concentrically arranged, the core layer nozzles 51 are in an annular structure, each core layer nozzle 51 simultaneously sprays and deposits a material of a core layer, and the first core layer nozzle is used for spraying hydrogen + silicon tetrachloride + germanium tetrachloride, the second core layer nozzle is used for spraying hydrogen, the third core layer nozzle is used for spraying argon, the fourth core layer nozzle is used for spraying oxygen, the fifth core layer nozzle is used for spraying argon, the sixth core layer nozzle is used for spraying hydrogen, the seventh core layer nozzle is used for spraying argon and the eighth core layer nozzle is. As shown in fig. 5, the first cladding torch 6 and the second cladding torch 7 have the same structure, and are respectively provided with ten concentrically arranged cladding nozzles 8, each cladding nozzle 8 is also in an annular structure, the ten cladding nozzles 8 simultaneously and respectively spray and deposit materials forming an outer cladding, and the first spray hydrogen + silicon tetrachloride, the second spray hydrogen, the third spray argon, the fourth spray oxygen, the fifth spray argon, the sixth spray hydrogen, the seventh spray argon, the eighth spray oxygen, the ninth spray argon and the tenth spray hydrogen are sequentially arranged from inside to outside.

In the deposition cavity 11, a seed rod 13 is hung on a hanger rod 12 to rotate, a core layer blast lamp 5 is used for depositing a loose core layer, SiCl4 and GeCl4 steam which are raw materials in a certain proportion are sprayed out through the core layer blast lamp 5, SiO2 and GeO2 generated by hydrolysis in oxyhydrogen flame are deposited on the seed rod 13, and the core layer blast lamp 5 is also used for controlling the size and the growth speed of the core layer. The primary material sprayed by the first cladding torch 6 and the second cladding torch 7 was SiCl4, and a cladding layer was deposited on the surface of the core layer. The suspender 12 is lifted upwards along the axial direction along with the deposition, the set deposition length is reached, and the deposition is finished.

As shown in FIG. 1, the loose body optical rod 9 is sent to the sintering device 2 for dehydration sintering after deposition cooling, the sintering device 2 comprises a sintering furnace 21, a vertically arranged furnace core pipe 22 is installed in the sintering furnace 21, and the inner diameter of the furnace core pipe 22 is 260mm and 280mm so as to adapt to the sintering of the large-size loose body optical rod 9. Wherein, a dehydration zone 211 and a sintering zone 212 positioned below the dehydration zone 211 are arranged in the sintering furnace 21, the temperature of the dehydration zone 211 is 1100-1200 ℃, and the temperature of the sintering zone 212 is 1500-1550 ℃. Thus, the loose body smooth rod 9 moves from top to bottom in the furnace core pipe 22, firstly passes through the dehydration region 211 for dehydration, then passes through the sintering region 212 for sintering at the speed of 4-8mm/min, and after sintering, the sintered mother rod is lifted out of the furnace core pipe 22. The temperature of the dehydration zone 211 is not too high, so that the density is prevented from increasing easily due to too high dehydration temperature; the temperature of the sintering zone 212 should not be too low to avoid sintering the loose body light bar 9 to be vitrified. In this embodiment, the diameter of the furnace core tube 22 is 260mm, the temperature of the dehydration zone 211 is 1100 ℃, and the temperature of the sintering zone 212 is 1500 ℃.

In addition, as shown in fig. 1, a gas inlet 221 is provided at the bottom of the muffle tube 22, and chlorine gas and helium gas are introduced into the gas inlet 221, and the flow rate of the chlorine gas is 0.6-1.5SLM and the flow rate of the helium gas is 20-30 SLM. Chlorine assists dehydration of the loose body optical rod 9, and helium has a high heat conductivity coefficient, so that the temperature of the sintering furnace 21 is more quickly and uniformly transferred into the furnace core pipe 22, and the dehydration sintering effect on the loose body optical rod 9 is improved. The flow control of the chlorine and the helium avoids the condition that the using effect cannot be achieved due to the small amount of the chlorine and the helium, and avoids the condition that the chlorine and the helium are too much and are easy to waste. In this example, the chlorine flow rate was 0.6SLM and the helium flow rate was 20 SLM.

As shown in fig. 1, dust and waste gas are generated in the deposition and dehydration sintering processes, and the direct discharge of the dust and waste gas can pollute the environment and has certain potential safety hazard, so the dust and waste gas are treated. Wherein, the side wall of the deposition chamber 11 opposite to the core layer blast lamp 5 is provided with an exhaust gas discharge pipe 14 communicated with the deposition chamber 11, the top of the furnace core pipe 22 is provided with a sealing cover 222, the side wall of the sealing cover 222 is provided with an exhaust pipe 223 communicated with the sealing cover, and the exhaust gas discharge pipe 14, the exhaust pipe 223 and the exhaust gas station 3 are arranged. The exhaust gas station 3 is the same as the prior art, and includes different exhaust gas treatment devices for classifying and treating the exhaust gas, which is not described herein in detail.

Example two:

as shown in fig. 1, 2 and 3, the difference between the second embodiment and the first embodiment is that in the present embodiment, the diameter of the seed rod 13 is 43mm, the included angle θ 1 between the axis of the core layer torch 5 and the axis of the seed rod 13 is 38 °, the included angle θ 2 between the axis of the first cladding torch 6 and the axis of the seed rod 13 is 47 °, and the included angle θ 3 between the axis of the second cladding torch 7 and the axis of the seed rod 13 is 58 °. The distance X1 between the center of the lamp holder of the core layer blast lamp 5 and the axis of the seed rod 13 in the X-axis direction is 40mm, the distance Y1 between the axis of the core layer blast lamp 5 and the axis of the seed rod 13 in the Y-axis direction is 0mm, and the distance Z1 between the intersection point of the center line of the core layer blast lamp 5 and the axis of the seed rod 13 in the Z-axis direction and the zero point of the seed rod 13 is 10 mm. The distance X2 between the center of the lamp holder of the first cladding torch 6 and the axis of the seed rod 13 in the X-axis direction is 80mm, the distance Y2 between the axis of the first cladding torch 6 and the axis of the seed rod 13 in the Y-axis direction is 0.5mm, and the distance Z2 between the intersection point of the center line of the first cladding torch 6 and the axis of the seed rod 13 in the Z-axis direction is 140mm, which is higher than the zero point of the seed rod 13. The distance X3 between the center of the lamp holder of the second cladding torch 7 and the axis of the seed rod 13 in the X-axis direction is 140mm, the distance Y3 between the axis of the second cladding torch 7 and the axis of the seed rod 13 in the Y-axis direction is-0.5 mm, and the distance Z3 between the intersection point of the center line of the second cladding torch 7 and the axis of the seed rod 13 in the Z-axis direction and the zero point of the seed rod 13 is 230 mm. The diameter of the furnace core pipe 22 is 270mm, the temperature of the dehydration zone 211 is 1150 ℃, and the temperature of the sintering zone 212 is 1525 ℃. The chlorine flow rate was 1.0SLM and the helium flow rate was 25 SLM.

Example three:

as shown in fig. 1, 2 and 3, the difference between the third embodiment and the first and second embodiments is that in the present embodiment, the diameter of the seed rod 13 is 45mm, the included angle θ 1 between the axis of the core layer torch 5 and the axis of the seed rod 13 is 40 °, the included angle θ 2 between the axis of the first cladding torch 6 and the axis of the seed rod 13 is 51 °, and the included angle θ 3 between the axis of the second cladding torch 7 and the axis of the seed rod 13 is 55 °. The distance X1 between the center of the lamp holder of the core layer blast lamp 5 and the axis of the seed rod 13 in the X-axis direction is 60mm, the distance Y1 between the axis of the core layer blast lamp 5 and the axis of the seed rod 13 in the Y-axis direction is 0.5mm, and the distance Z1 between the intersection point of the center line of the core layer blast lamp 5 and the axis of the seed rod 13 in the Z-axis direction is 15mm, which is higher than the zero point of the seed rod 13. The distance X2 between the center of the lamp holder of the first cladding torch 6 and the axis of the seed rod 13 in the X-axis direction is 120mm, the distance Y2 between the axis of the first cladding torch 6 and the axis of the seed rod 13 in the Y-axis direction is-0.5 mm, and the distance Z2 between the intersection point of the center line of the first cladding torch 6 and the axis of the seed rod 13 in the Z-axis direction is 120mm, which is higher than the zero point of the seed rod 13. The distance X3 between the center of the lamp socket of the second cladding torch 7 and the axis of the seed rod 13 in the X-axis direction is 150mm, the distance Y3 between the axis of the second cladding torch 7 and the axis of the seed rod 13 in the Y-axis direction is 0mm, and the distance Z3 between the intersection point of the center line of the second cladding torch 7 and the axis of the seed rod 13 in the Z-axis direction and the zero point of the seed rod 13 is 220 mm. The diameter of the furnace core tube 22 is 280mm, the temperature of the dehydration region 211 is 1200 ℃, and the temperature of the sintering region 212 is 1550 ℃. The chlorine flow rate was 1.5SLM and the helium flow rate was 30 SLM.

Table 1 schematically compares the loose body optical wand 9 outer diameter D1, the loose body optical wand 9 core diameter D1, the sintered mother wand outer diameter D, the sintered mother wand core diameter D, the core ratio D/D, the core relative refractive index difference Δ n prepared in the above three embodiments of the present invention, wherein the mother wand is the core wand after being stretched, the core ratio of the core wand is substantially equal to the core ratio of the mother wand, so the core ratio of the mother wand is directly used to represent the core ratio of the core wand.

Table one:

as can be seen from the comparison of Table I, the core rod prepared in example I has the smallest relative refractive index difference of the core, the largest size of the core rod prepared in example II, and the smallest core-spun ratio of the core rod prepared in example III. The seed rod 13, the angle and position of the core torch 5, the first cladding torch 6 and the second cladding torch 7 may be selected, in practice, according to the desired core rod size or the requirements for core rod performance.

While the foregoing description shows and describes the preferred embodiments of the present invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not intended to be exhaustive or to exclude other embodiments and may be used in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be limited only by the claims appended hereto.

Claims (8)

1. A core rod preparation device for a large-size optical fiber preform comprises a deposition device (1) and a sintering device (2), wherein the deposition device (1) comprises a deposition cavity (11), a vertically arranged hanging rod (12) is arranged at the top of the deposition cavity (11), and the upper end of the hanging rod (12) is connected with a driving device which drives the hanging rod to rotate around the axis of the hanging rod and move up and down along the vertical direction; the method is characterized in that: a seed rod (13) coaxial with the hanger rod is arranged below the hanger rod (12), and the diameter of the seed rod (13) is 40-45 mm; a core layer blast lamp (5), a first cladding blast lamp (6) and a second cladding blast lamp (7) which are sequentially arranged from bottom to top are further arranged in the deposition cavity (11), an included angle between the axis of the core layer blast lamp (5) and the axis of the seed rod (13) is theta 1, an included angle between the axis of the first cladding blast lamp (6) and the axis of the seed rod (13) is theta 2, an included angle between the axis of the second cladding blast lamp (7) and the axis of the seed rod (13) is theta 3, the theta 1 is 36-40 degrees, the theta 2 is 47-51 degrees, and the theta 3 is 55-60 degrees; when the deposition is started, in the X-axis direction, the distance between the core layer blast lamp (5) and the axis of the seed rod (13) is 20-60mm, the distance between the first cladding layer blast lamp (6) and the axis of the seed rod (13) is 80-120mm, and the distance between the second cladding layer blast lamp (7) and the axis of the seed rod (13) is 140-160 mm; in the Y-axis direction, the distances among the axes of the core layer blast lamp (5), the first cladding blast lamp (6), the second cladding blast lamp (7) and the seed rod (13) are all-0.5-0.5 mm; in the Z-axis direction, the intersection point of the central line of the core layer blast lamp (5) and the axis of the seed rod (13) is 5-15mm higher than the zero point of the seed rod (13), the intersection point of the central line of the first cladding blast lamp (6) and the axis of the seed rod (13) is 140mm higher than the zero point of the seed rod (13), and the intersection point of the central line of the second cladding blast lamp (7) and the axis of the seed rod (13) is 240mm higher than the zero point of the seed rod (13) of 220-.

2. The apparatus of claim 1, wherein: the sintering device (2) comprises a sintering furnace (21), wherein a vertically arranged furnace core pipe (22) is arranged in the sintering furnace (21), and the inner diameter of the furnace core pipe (22) is 260-280 mm.

3. The apparatus of claim 2, wherein: a dehydration zone (211) and a sintering zone (212) positioned below the dehydration zone (211) are arranged in the sintering furnace (21), the temperature of the dehydration zone (211) is 1100-1200 ℃, and the temperature of the sintering zone (212) is 1500-1550 ℃.

4. The apparatus of claim 2, wherein: the bottom of the furnace core pipe (22) is provided with an air inlet (221), chlorine and helium are introduced into the air inlet (221), the flow rate of the chlorine is 0.6-1.5SLM, and the flow rate of the helium is 20-30 SLM.

5. The apparatus of claim 1, wherein: the sandwich layer blowtorch (5) is provided with eight annular sandwich layer nozzles (51) which are concentrically arranged, and each sandwich layer nozzle (51) simultaneously sprays hydrogen, silicon tetrachloride, germanium tetrachloride, hydrogen, argon, oxygen, argon, hydrogen, argon and oxygen from inside to outside.

6. The apparatus of claim 5, wherein: first cladding blowtorch (6) and second cladding blowtorch (7) all are equipped with annular cladding spout (8) of ten concentric settings, from inside to outside every cladding spout (8) jet hydrogen + silicon tetrachloride, hydrogen, argon, oxygen, argon, hydrogen respectively simultaneously.

7. The apparatus of claim 4, wherein: be equipped with on sedimentation chamber (11) lateral wall rather than the exhaust emission pipe (14) of intercommunication, stove core pipe (22) top is equipped with closing cap (222), be equipped with on closing cap (222) lateral wall rather than the blast pipe (223) of intercommunication, exhaust emission pipe (14) and blast pipe (223) are connected exhaust station (3).

8. The apparatus of claim 1, wherein: the annealing furnace also comprises an annealing furnace (4), wherein the temperature of the annealing furnace (4) is 1100 ℃, and the annealing time is more than 15 h.

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