WO2024169598A1 - System and method for depositing quartz glass cylinder - Google Patents

Abstract

The present invention relates to a system and method for depositing a quartz glass cylinder. The system comprises a deposition chamber, wherein upper and lower rotating chucks are provided in the deposition chamber; blowtorches arranged at intervals in an up-down direction are provided corresponding to the upper and lower rotating chucks; the upper and lower rotating chucks or the blowtorches are connected to an up-down movement device; and one side of the deposition chamber is communicated with a gas inlet chamber, and the other side of the deposition chamber is communicated with a gas pumping chamber. The system is characterized in that each blowtorch comprises a raw gas nozzle and a fuel gas nozzle, the outermost ring of the blowtorch nozzle is provided with an annular gas nozzle, and the annular gas nozzle is in communication with a temperature-adjustable gas source. According to the present invention, the annular gas nozzle ejects gas to form a cylindrical gas curtain, and a cover in front of the blowtorch is replaced with the gas curtain stabilizing gas flow, so that gas of a deposition area can be confined in a gas ring, and a stable gas flow field is provided for a reaction area of silicon dioxide, thereby ensuring the consistency of the whole deposition process. Moreover, the temperature of the gas introduced into the gas ring may gradually change with the deposition process, thereby realizing uniform temperature distribution of upper and lower thermal fields of the deposition area, and thus improving the deposition quality.

Description

A quartz glass cylinder deposition system and method Technical Field

The present invention relates to a deposition system and method for a quartz glass cylinder, and in particular to a system and method for preparing a synthetic quartz glass cylinder by an outside vapor deposition (OVD) method. The quartz glass cylinder can be used in the fields of optical fiber preforms, optical devices and semiconductor technology.

Background Art

The production of quartz glass cylinders by outside vapor deposition (OVD) is an important and well-known method for obtaining high-purity synthetic silica quartz glass products, which are widely used in optical fiber, optical glass and semiconductor industries due to their outstanding material properties. The OVD process is that a deposition torch deposits a silica nano gas flow on a target rod to form a porous silica powder rod preform, and then the porous silica powder rod preform is sintered in vacuum or helium to form a non-porous pure silica quartz glass cylinder.

In the vapor deposition method, the blowtorch uses a glass blowtorch, which is generally processed by fire and has low precision. For example, the roundness and concentricity of the blowtorch material tube and the gas tube are poor. After a long deposition period, dust is easily accumulated at the material tube mouth, which leads to crystallization and powder rod product defects, resulting in excessive scrap. The consistency and repeatability of multiple glass blowtorches are poor. Multiple lamps are used for deposition on a target rod, and the powder rod diameter is unevenly distributed, causing the optical parameters of the optical fiber to be scrapped.

The deposition mechanism of OVD is thermophoresis, which refers to the effect of temperature gradient on particles, which causes particles to move from a high temperature area to a low temperature area. It can be seen that temperature gradient is the main factor affecting deposition. The higher the particle temperature and the lower the target temperature, the higher the collection rate and deposition efficiency. However, OVD targets generally use rotating target rods, and the blowtorch uses multiple small-area blowtorches. As disclosed in Chinese patent CN1215002, the area where the blowtorch flame is deposited has a high temperature. When leaving the flame, the temperature of the deposition surface drops rapidly, especially for large-diameter powder rods. This phenomenon is more serious. The thermal stress generated by the rise and fall of temperature sharply increases the risk of cracking of the powder rod, resulting in the scrapping of the product.

International patent WO2004002911 mentions that the cylindrical burner in the conventional OVD device deposits a density gradient with a radial direction on the target rod, which will form a spiral deposition pattern on the deposition surface, and finally form ripples on the periphery after sintering. In addition, during the preparation process, the target rod is vertically installed in the reaction chamber, and multiple blowtorches move up and down while depositing on the target rod. Due to the chimney effect, the hot air rises, causing the temperature of the upper end of the target rod to be higher than that of the lower end. In addition, the rapid movement of the cylindrical burner and the target rod may also cause turbulence in the stratified flow of the flame, which intensifies the density differentiation of the deposited powder rod and affects the quality of the deposited product.

US Patent US2018022147 discloses that in order to obtain a higher smoke collection rate and deposition rate, the second smoke pipe is moved inside the first smoke pipe to adjust the effective diameter of the pores so that the second spraying size of the smoke in the later stage of deposition is larger than the sprayed size. The collection rate and deposition rate of deposition are improved. However, in such a small space as the blowtorch, it is technically difficult to implement precise movement of the material tube while ensuring precise sealing, which will reduce the reliability and stability of the equipment.

Summary of the invention

The technical problem to be solved by the present invention is to provide a quartz glass cylinder deposition system and method in view of the deficiencies in the above-mentioned prior art, which has uniform thermal field temperature distribution, good deposition quality and stable process.

The deposition system technical solution adopted by the present invention to solve the above-mentioned problems is:

The method comprises a deposition chamber, in which an upper and a lower rotating chuck are arranged, and blowtorches spaced up and down are arranged corresponding to the upper and lower rotating chucks, the upper and lower rotating chucks or the blowtorches are connected to an up and down moving device, one side of the deposition chamber is connected to an air inlet chamber, and the other side of the deposition chamber is connected to an exhaust chamber, and the characteristic is that the blowtorch comprises a raw material gas nozzle and a fuel gas nozzle, and an air ring nozzle is arranged at the outermost circle of the blowtorch nozzle, and the air ring nozzle is connected to a temperature-adjustable gas source.

According to the above scheme, a raw gas nozzle is set in the middle of the blowtorch, and the raw gas nozzle includes a central hole raw gas nozzle and 1 to 3 layers of annular raw gas nozzles surrounding the central hole raw gas nozzle. The raw gas nozzle is connected to the raw gas source.

According to the above scheme, the 1 to 3 layers of annular raw material gas nozzles are simultaneously connected to the inert gas source through a conversion (switching) valve.

According to the above scheme, the fuel gas nozzle is an annular fuel gas nozzle, which is arranged on the periphery of the raw gas nozzle. The annular fuel gas nozzle includes a hydrogen nozzle and an oxygen nozzle. The hydrogen nozzle and the oxygen nozzle are respectively arranged in 1 to 2 layers. The fuel gas nozzle is connected to the fuel gas source.

According to the above scheme, an annular inert gas nozzle is arranged between the raw gas nozzle and the fuel gas nozzle, and the annular inert gas nozzle is connected to the inert gas source.

According to the above scheme, the air ring nozzle is arranged on the periphery of the fuel gas nozzle. The air ring nozzle is composed of annular pores or closely spaced annular small holes. The air ring nozzle is arranged in 1 to 2 layers. The gas ejected from the air ring nozzle forms a cylindrical air curtain, which covers the combustion raw material reaction gas in the cylindrical air curtain.

According to the above scheme, the raw material gas nozzle arranged in the middle of the blowtorch is a movable raw material gas nozzle, and the rear end of the movable raw material gas nozzle is connected to the rotating support mechanism, and the rotating support mechanism drives the movable raw material gas nozzle to rotate slowly.

According to the above scheme, the movable raw material gas nozzle is in the shape of a circular shaft, and an annular pore is formed with the inner hole of the burner body through the connection support of the rotating support mechanism, and the annular pore constitutes an annular inert gas nozzle.

According to the above solution, the blowtorch is made of metal or alloy.

According to the above scheme, upper and lower rotating baffles are correspondingly arranged on the upper and lower rotating chucks.

According to the above scheme, the air inlet chamber is located on the back side of the blowtorch, the front of the air inlet chamber is connected to the deposition chamber, the back of the air inlet chamber is connected to the sub-air inlet chambers separated from each other, and an electric heating device is provided at the air inlet of each sub-air inlet chamber to heat the incoming air. Warming of the body.

According to the above scheme, the air inlet of the sub-air inlet chamber is connected to the gas filter chamber, and a gas filter is arranged in the gas filter chamber.

According to the above scheme, the exhaust chamber is located on the front side of the blowtorch, the front of the exhaust chamber is connected to the deposition chamber, the back of the exhaust chamber is connected to the sub-exhaust chamber separated into upper and lower parts, and an air volume regulating valve is connected in series at the air outlet of each sub-exhaust chamber to adjust the flow rate of the extracted gas, and the air outlet of the sub-exhaust chamber is connected to the exhaust duct.

According to the above scheme, 6 to 12 sub-air inlet chambers are arranged above and below corresponding to the air inlet chamber, and 6 to 12 sub-air exhaust chambers are arranged above and below corresponding to the air exhaust chamber.

According to the above scheme, the exhaust duct is connected to (in parallel with) the exhaust gas recovery duct, an exhaust gas recovery pump is installed in the exhaust gas recovery duct, and the other end of the exhaust gas recovery duct is connected to the gas filter chamber, so that part of the heat of the exhaust gas can be recovered.

According to the above scheme, the side walls on both sides of the deposition chamber are provided with guide fin devices that can swing up and down.

According to the above scheme, the guide fin device includes guide fins that are hinged to the side wall and arranged in parallel and spaced apart. The inner end of the guide fin extends into the inner side of the deposition chamber. The outer end of the guide fin is hinged to the up and down movable rocker rod, and the up and down movable rocker rod is connected to the reciprocating drive mechanism.

The technical solution of the deposition method of the present invention is:

First, clamp the deposition target rod on the upper and lower rotating chucks, open the air inlet and exhaust chambers, heat the air inlet and adjust the exhaust volume to make the deposition chamber reach the preset temperature and pressure range.

Then, the upper and lower rotating chucks are turned on to drive the deposition target rod to rotate, and the up and down moving device is turned on to make the upper and lower rotating chucks and the blowtorch move up and down relatively, and the blowtorch is ignited to spray the raw material gas, fuel gas and inert gas and burn them together to generate silicon dioxide reactants that are deposited on the periphery of the target rod.

The feature of the invention is that the air ring nozzle of the blowtorch sprays a cylindrical air curtain heating gas, and the temperature of the heating gas sprayed by each blowtorch is automatically adjusted according to the temperature feedback of the spraying area, so that the temperature of the upper and lower deposition areas of the target rod tends to be consistent, and the blowtorch continues to spray until the deposition is completed.

According to the above scheme, the temperature of the gas ejected from the gas ring nozzle is in the range of 25 to 500°C, the gas flow rate is 0.3 to 40 m/s, and the best is 1.0 to 20 m/s. This flow rate can protect the reaction zone of silicon dioxide in the gas ring of stable airflow, so that the silicon dioxide particles generated from the nozzle of the blowtorch are in the gas field of stable airflow until they are deposited on the powder rod. The ejected gas can be hot gas recovered from exhaust gas, clean air or inert gas (such as nitrogen) that is heated and filtered, or combustion gas of hydrogen and oxygen or alkane oxygen.

According to the above scheme, as the diameter of the target rod deposition gradually increases, on the basis of first opening the central hole raw material gas nozzle, 1 to 3 layers of annular raw material gas nozzles surrounding the central hole raw material gas nozzle are opened layer by layer, and the injection amount of raw material gas is gradually increased. At the same time, the second layer of fuel gas nozzles are opened, and the injection amount of fuel gas is gradually increased to form a coaxial jet flame to achieve the best The collection rate and deposition rate.

According to the above scheme, the formula for the attenuation of the axial velocity of the coaxial jet flame is:

in

_Qi is the mass flow rate of the i-th group of jets in kg/s, _pi is the momentum flux of the i-th group of jets in kg·m/s ² , a＝0.076, b＝0.147, _um is the center jet velocity, _u0 is the center jet initial velocity, _d0 is the corresponding diameter, ρ is the gas density, and x is the distance from the feed pipe mouth.

Preferably, the central jet velocity um reaching 30 mm from the deposition target surface _is between 15 and 90 m/s.

More preferably, the central jet velocity um reaching 30 mm from the deposition target surface _is between 25 and 80 m/s.

More preferably, the central jet velocity um reaching 30 mm from the deposition target surface _is between 35 and 70 m/s.

According to the above scheme, when the deposition is stable, the temperature below the target rod deposition area is low, the temperature above is high, and the temperature difference maintains a stable trend. The gas is injected through the gas ring nozzle, or the gas injection from the gas ring nozzle is combined with the upper and lower rotating baffles for heat compensation. The compensation mechanism is as follows: The length of the target rod deposition area is L, starting from the bottom of the target rod, and the length x (corresponding to the position of the blowtorch) is selected upward:

①x<0.6L, heat compensation formula:
Q complement = e*x ² -f*x+g

Where, Qcompensation is the heat to be compensated, in kw; e = 6*10 ^-06 ～ 9*10 ^-06 ; f = 0.0366～0.0443; g = 57.708～59.055

Only the gas ring nozzle performs thermal compensation for temperature: Q compensation = 9*10 ^-06 x ² -0.0443x+57.708

Gas ring + upper and lower rotating baffles for temperature thermal compensation: Q compensation = 6*10 ^-06 x ² -0.0366x+59.055

②L>x≥0.6L, heat compensation: Qcompensation＝0.

According to the above scheme, the sub-inlet chamber of the air inlet chamber automatically adjusts the air inlet temperature according to the temperature feedback of the separated deposition area, so that the temperature of the upper and lower deposition areas of the target rod is further consistent. The temperature compensation of the air inlet chamber and the temperature compensation gas of the blowtorch air ring nozzle are used together to ensure that the temperature of the powder rod surface is consistent during the entire deposition process and is not affected by the deposition time and the upper and lower parts of the deposition. In the early stage of deposition, the temperature of the rotating target rod and the deposition chamber approaches room temperature, and the temperature of the air inlet chamber is compensated to 400°C, which is the same above and below the air inlet chamber. The gas temperature of the upper air ring nozzle of the blowtorch is 800°C, and the surface temperature of the entire target rod is maintained at more than 500°C and less than 1200°C. In the middle stage of deposition, the deposition reaction occurs, causing the cavity temperature to rise, and the chimney effect is obvious. The temperature compensation of the air inlet chamber decreases from 400°C, and the temperature gradually decreases from bottom to top. At the same time, the temperature compensation air ring The compensation temperature is gradually reduced to keep the surface temperature of the entire target rod greater than 500℃ and less than 1200℃; at the end of deposition, the temperature compensation of the air inlet chamber and the temperature compensation gas ring on the blowtorch are first heated up to keep the surface temperature of the entire target rod greater than 500℃ and less than 1200℃, and then gradually cooled down to anneal the powder rod. With this scheme, the temperature difference during the deposition process can be maintained at a certain level (±50℃), the density of the powder rod is consistent in the radial and longitudinal directions, and the refractive index and optical average level after sintering are also consistent.

According to the above scheme, the sub-exhaust chamber of the exhaust chamber adjusts the flow rate of the extracted gas through the air volume regulating valve according to the injection amount and deposition amount of the raw material gas, thereby ensuring that the deposited dust is extracted in time.

According to the above scheme, the tail gas recovery pump is turned on, so that part of the tail gas is recovered to the gas filter chamber through the tail gas recovery pipeline, so that part of the heat of the tail gas is recovered.

The beneficial effects of the present invention are as follows: 1. An air ring nozzle is provided at the outermost circle of the blowtorch nozzle, and the air ring nozzle is connected to a temperature-adjustable gas source. The gas ejected from the air ring nozzle forms a cylindrical air curtain. The air curtain with a stable airflow is used to replace the cover in front of the blowtorch, so that the gas in the deposition area can be confined in the gas ring, providing a stable airflow field for the reaction zone of silicon dioxide, making it less affected by temperature or airflow, avoiding the chimney effect and other airflow disturbances to the reaction deposition zone, and ensuring the consistency of the entire deposition process. At the same time, the temperature of the gas introduced into the air ring can gradually change with the deposition process, so that the temperature distribution of the upper and lower thermal fields in the deposition area is uniform, thereby improving the deposition quality. 2. The upper and lower rotating baffle structures are provided to perform heat compensation for the air ring injection temperature, so that the temperature distribution of the upper and lower thermal fields is more uniform. 3. Use a multi-layer annular raw material gas nozzle, i.e. a multi-layer material tube structure. As the diameter of the deposited powder rod increases, the raw material gas is introduced into the material tube layer by layer, so that the ejected material matches the formed diameter of the powder rod. The use of multi-layer feeding can increase the concentration of SiO2 particles during the burner combustion process, and the SiO2 that hits the surface of the powder rod is more uniform, which can achieve the best collection rate and deposition rate of large-sized quartz glass powder rods. 4. Set up a movable raw material gas nozzle to rotate the overall multi-layer material tube structure relative to the blowtorch, reduce the eccentricity of the gap between the material tube and the inert gas nozzle or the fuel gas nozzle, and use rotation to greatly reduce the dust accumulation in the local part of the nozzle, thereby reducing crystallization, especially the dust clogging crystallization phenomenon that occurs in the late stage of large powder rod deposition. The blowtorch of the present invention can be a metal blowtorch with high mechanical strength and good wear resistance, and high manufacturing precision, which is convenient for production and maintenance. 5. The air inlet chamber is set as a sub-air inlet chamber structure separated from top to bottom, which can regulate the temperature of the gas sent into different areas of the deposition chamber, and heat and adjust the temperature of different deposition areas according to different situations. The temperature adjustment area is larger, which can make the upper and lower temperature distribution of the entire deposition chamber, especially the powder rod deposition area, more uniform and consistent, thereby effectively improving the deposition quality of the OVD process. 6. The setting of the sub-exhaust chamber is conducive to the uniformity and smoothness of the air flow field, and at the same time promotes the uniformity of the temperature field, avoiding the dust that comes out of the blowtorch and is not collected on the powder rod to form a vortex in front of the powder rod and the exhaust pipe mouth, and then deposit on the powder rod again to form a bulge, causing the powder rod to be scrapped. The exhaust gas recovery pipeline is installed to allow part of the exhaust gas to be recovered to the gas filter chamber, so that part of the heat of the higher temperature exhaust gas can be recycled and utilized, achieving the effect of energy saving and saving.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the overall structure of an embodiment of the present invention.

FIG. 2 is a schematic diagram of the front view of the structure of a blowtorch according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of the side structure of a blowtorch according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of airflow restriction of a blowtorch air ring according to an embodiment of the present invention.

FIG. 5 is a schematic structural diagram of an upper and lower rotating baffle and a guide fin device according to an embodiment of the present invention.

FIG6 and FIG7 are respectively the OMCTS distribution diagrams of the single-layer material pipe and the double-layer material pipe simulated by the present invention.

Figures 8 and 9 are respectively the SiO2 distribution diagrams of the single-layer material tube and the double-layer material tube simulated by the present invention.

FIG. 10 is a temperature distribution diagram of a single blowtorch spraying on a powder rod in Example 1 of the present invention and Comparative Example 1.

FIG. 11 is a comparison diagram of the longitudinal surface temperature distribution of the powder rods in Examples 1 and 3 of the present invention and Comparative Example 1.

DETAILED DESCRIPTION

The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

The deposition system of the present invention comprises a box-shaped deposition chamber 7, in which upper and lower rotating chucks 8 and 15 are arranged, the upper and lower rotating chucks clamp the deposition target rod, and upper and lower rotating baffles 9 and 14 are arranged on the upper and lower rotating chucks respectively, the upper and lower rotating baffles are located at the upper and lower ends of the deposition target rod, and rotate together with the upper and lower rotating chucks and the deposition target rod. A blowtorch 6 with upper and lower intervals is arranged corresponding to the upper and lower rotating chucks, and the blowtorch is connected to an upper and lower reciprocating moving device, and the blowtorch comprises a raw material gas nozzle and a fuel gas nozzle, the raw material gas nozzle comprises a central hole raw material gas nozzle 19 and a middle layer annular raw material gas nozzle 20 surrounding the central hole raw material gas nozzle, and an outer layer annular raw material gas nozzle 21, the raw material gas nozzle is connected to a raw material gas source, and the annular raw material gas nozzle is simultaneously connected to an inert gas source through a conversion (switching) valve. The raw material gas nozzle arranged in the middle of the burner is a movable raw material gas nozzle, and the rear end of the movable raw material gas nozzle is connected to the rotating support mechanism, and the rotating support mechanism drives the movable raw material gas nozzle to rotate slowly. The rotating support mechanism includes a fixed seat 29 connected to the burner body 18, and a driving shaft 30 is arranged in the fixed seat. One end of the driving shaft is connected to the driving device 28, and the other end is connected to the movable raw material gas nozzle through a connecting plate 25 and a sealing ring 31. The movable raw material gas nozzle is in the shape of a circular shaft, and the rear end is a shoulder with a larger diameter. The through holes of each layer of raw material gas nozzles opened in the movable raw material gas nozzle are connected to each material through hole on the driving shaft, and each material through hole is matched with the rotating valve port 27 arranged on the fixed seat, and is connected to the raw material gas source. The movable raw material gas nozzle is connected to the inner hole of the burner body through the connecting support of the rotating support mechanism to form an annular pore, and the annular pore constitutes an annular inert gas nozzle 22, and the inert gas nozzle is connected to the inert gas source. The fuel gas nozzle 24 is an annular fuel gas nozzle, which is arranged at the periphery of the inert gas nozzle. The annular fuel gas nozzle includes a hydrogen nozzle and an oxygen nozzle. The hydrogen nozzle and the oxygen nozzle are respectively arranged in two layers. The fuel gas nozzle is connected to the fuel gas source. An air ring nozzle 23 is arranged at the outermost circle of the blowtorch nozzle. The air ring nozzle is arranged at the periphery of the fuel gas nozzle. The air ring nozzle is composed of annular pores or closely spaced annular small holes. The gas ejected from the air ring nozzle forms a cylindrical air curtain, which covers the combustion raw material reaction gas in the cylindrical air curtain. The air ring nozzle is connected to a temperature-adjustable gas source 16. The temperature of the gas introduced into the air ring nozzle can gradually change with the deposition process. The gas can be heated by the heat recovered from the exhaust gas, or by electrically heating the gas in the air ring to reach the set temperature, or by its own gas reaction. High-temperature gas is obtained (the gas itself can be a combustible gas such as hydrogen, oxygen and alkane gas). The gas ring nozzle, the fuel gas nozzle and the inert gas nozzle are matched with the valve port 26 on the nozzle body through various through holes. The blowtorch is made of metal or alloy. Figures 6 and 7 simulate the distribution comparison of OMCTS (octamethylcyclotetrasiloxane, C ₈ H ₂₄ O ₄ Si ₄ , D4) in a single-layer material tube and a double-layer material tube. Figure 6 is an OMCTS concentration diagram at the initial stage of powder rod deposition. When the powder rod grows, OMCTS is gradually added to the second layer of the material tube and switched to the state of Figure 7. The multi-layer feeding method increases the feed amount of OMCTS, so the deposition rate will be further improved. Figures 8 and 9 simulate the SiO2 distribution comparison of single-layer material tubes and double-layer material tubes. Figure 8 is a SiO2 concentration diagram at the initial stage of powder rod deposition. When the powder rod grows, the second-layer material tube gradually adds OMCTS and switches to the state of Figure 9. The use of multi-layer feeding can increase the concentration of SiO2 particles during the burner combustion process, and the SiO2 that hits the surface of the powder rod is more uniform, thereby improving the collection rate. One side of the deposition chamber 7 is connected to the air inlet chamber, which is located on the back side of the blowtorch. The front 5 of the air inlet chamber is connected to the deposition chamber, and the back of the air inlet chamber is connected to the sub-air inlet chamber 4 separated from each other. An electric heating device 3 is set at the air inlet of each sub-air inlet chamber for heating the incoming gas. The air inlet of the sub-air inlet chamber is connected to the gas filter chamber 1, and a gas filter 2 is set in the gas filter chamber. The other side of the deposition chamber is connected to the exhaust chamber, and the exhaust chamber is located on the front side of the blowtorch. The front 10 of the exhaust chamber is connected to the deposition chamber, and the back of the exhaust chamber is connected to the sub-exhaust chamber 11 separated up and down. The air outlet of each sub-exhaust chamber is connected in series with an air volume regulating valve 13 for adjusting the flow of the extracted gas, and the air outlet of the sub-exhaust chamber is connected to the exhaust duct 12. The exhaust duct is connected to (in parallel with) the exhaust gas recovery duct 17, and an exhaust gas recovery pump 17a is installed in the exhaust gas recovery duct. The other end of the exhaust gas recovery duct is connected to the gas filter chamber, so that part of the heat of the exhaust gas can be recovered. The exhaust duct uses negative pressure for exhaust, and the exhaust gas recovery is controlled by the exhaust gas recovery pump, thereby saving energy and reducing emissions. The side walls on both sides of the deposition chamber are provided with guide fin devices that can swing up and down. The guide fin devices include guide fins 32 that are arranged in parallel and spaced apart from each other and are hinged to the side wall hinges 34. The outer ends of the guide fins are hinged to the up and down movable rocker rods 33. The inner ends of the guide fins extend into the inner side of the deposition chamber and extend for a certain length. The up and down movable rocker rods are connected to the reciprocating drive mechanism.

The embodiments of the deposition powder rod of the present invention are as follows:

Example 1

The blowtorch adopts a gas ring nozzle + 2 layers of raw material gas nozzles + inert gas nozzles + 2 layers of fuel gas nozzles. The raw material gas nozzle is a movable raw material gas nozzle structure: the gas ring nozzle is composed of a circular ring, the narrow slit width of the circular ring is 2mm, and the gas is supplied by nitrogen. In the initial deposition, the nitrogen in the gas ring is heated to 100°C by electric heating. When the exhaust temperature reaches above 150°C, the heat recovered from the exhaust gas is used to heat the nitrogen to more than 120°C, but less than 480°C. The gas flow rate of nitrogen in the entire deposition stage is 20m/s. Two layers of raw material gas nozzles are used, the diameter of the central hole raw material nozzle hole is 2mm, and the wall thickness is 0.3mm; the diameter of the outer layer annular raw material nozzle is 4.5mm, wherein the flow rate of the material-carrying gas in the raw material nozzle is 35m/s, and the material-carrying gas is nitrogen gas with octamethylcyclotetrasiloxane. At the beginning of deposition, the central nozzle is supplied with material gas (gas flow rate is 35m/s), and the outer annular raw material nozzle is supplied with inert gas (gas flow rate is 15m/s); the powder rod diameter reaches 250mm As shown above, the outer annular raw material nozzle switches the inert gas to the material-carrying gas (gas flow rate is 35m/s), and the powder rod diameter is finally deposited to 500mm. The outer layer of the raw material gas nozzle is the inert gas nozzle and the fuel gas nozzle in turn. The inert gas nozzle 5 introduces nitrogen with a gas flow rate of 15m/s; the fuel gas nozzle 7 is divided into two layers, the hydrogen nozzle is adjacent to the inert gas nozzle, and the oxygen nozzle is adjacent to the outside. The flow rates of the hydrogen and oxygen nozzles are both 15m/s. After testing, the deposition rate of the powder rod is 240g/min, and the collection rate is 75.8%. The rotation speed of the active raw material gas nozzle is 2r/min. According to the production statistics, 203 powder rods were deposited and scrapped because of the accumulation and crystallization of dust at the material mouth.

Example 2

The blowtorch uses 2 layers of gas ring nozzles + 3 layers of raw gas nozzles + inert gas nozzles + 2 layers of fuel gas nozzles. The raw gas nozzles are active raw gas nozzle structures: the gas ring nozzles are composed of two circles of closely spaced 1mm diameter circular holes. The outer circle uses hydrogen and the inner circle uses oxygen. The volume of oxygen consumed per minute/the volume of hydrogen consumed per minute = 1:2. The gas flow rate of hydrogen and oxygen is 35m/s. A three-layer material pipe is used. The diameter of the center hole raw material nozzle is 2.5mm and the wall thickness is 0.2mm; the diameter of the middle layer ring raw material nozzle is 5mm and the wall thickness is 0.2mm; the diameter of the outer layer ring raw material nozzle is 8mm and the wall thickness is 0.2mm. The raw material gas is helium gas with silicon tetrachloride. At the beginning of deposition, the central hole nozzle is raw material gas (gas flow rate is 35m/s), and the middle and outer annular raw material nozzles are passed through inert gas (gas flow rate is 15m/s); when the powder rod diameter reaches more than 300mm, the outer layer material nozzle switches the inert gas to raw material gas (gas flow rate is 35m/s), the gas flow rate of the central material nozzle increases to 45m/s, and the middle layer material nozzle passes through inert gas (gas flow rate is 15m/s); when the powder rod diameter reaches more than 500mm, the middle layer material nozzle switches the inert gas to material-carrying gas (gas flow rate is 35m/s), the gas flow rate of the central material nozzle increases to 50m/s, and the gas flow rate of the middle layer material nozzle is 45m/s; finally, the powder rod diameter reaches 750mm. The outer layer of the raw material gas nozzle is the inert gas nozzle and the fuel gas nozzle. Nitrogen is introduced into the inert gas nozzle, and the gas flow rate is 15m/s; the fuel gas nozzle is divided into two layers, the oxygen pipe is adjacent to the inert gas nozzle, and the hydrogen nozzle is adjacent to the outside. The flow rates of the hydrogen and oxygen nozzles are both 25m/s. Finally, the test results show that the deposition rate of the powder rod is 220g/min and the collection rate is 72.5%. The rotation speed of the active raw material gas nozzle is 1r/min. According to the production statistics, 196 powder rods were deposited before the dust accumulation and crystallization at the material mouth caused the powder rods to be scrapped.

Example 3

Same as Example 1, in addition, upper and lower rotating baffles are correspondingly installed on the upper and lower rotating chucks, and the upper and lower rotating baffles are located at the upper and lower ends of the deposition powder rod, and rotate together with the upper and lower rotating chuck dust collector target rods. The upper and lower rotating baffle structures can perform heat compensation for the air ring injection temperature, so that the temperature distribution of the upper and lower thermal fields is more uniform, as shown in Figure 11.

Comparative Example 1

The blowtorch uses a 60mm long glass cover + a layer of raw material gas nozzles, the raw material gas nozzles do not rotate: a layer of material tube is used, the diameter of the central material nozzle is 3.5mm, wherein the flow rate of the raw material gas in the material tube hole is 35m/s, and the raw material gas is nitrogen gas with octamethylcyclotetrasiloxane. The outer layer of the raw material gas nozzle is an inert gas nozzle and a fuel gas nozzle in turn, nitrogen is introduced into the inert gas nozzle, and the gas flow rate is 15m/s; the fuel gas nozzle 7 is divided into two layers, and the one next to the inert gas nozzle is The hydrogen nozzle is adjacent to the oxygen nozzle. The flow rate of the hydrogen and oxygen nozzles is 15m/s. The powder rod diameter is deposited to 500mm. The test results show that the deposition rate of the powder rod is 180g/min and the collection rate is 65.8%.

During continuous production, 32 powder rods were scrapped due to dust accumulation and crystallization at the material inlet.

FIG10 compares Example 1 and Comparative Example 1. Example 1 uses an air ring, while Comparative Example 1 uses a 60 mm long glass cover. Both are temperature distribution diagrams of a single blowtorch spraying on a powder rod when the powder rod has a diameter of 245 mm. Because the air ring can stabilize the reaction gas flow sprayed from the blowtorch better than the glass cover and mitigate the chimney effect, the temperature on the powder rod in Example 1 is more uniform than that in Comparative Example 1, thereby improving the dust collection rate and deposition rate.

Figure 11 compares Comparative Example 1, Example 1 and Example 3. Example 1 adopts an air ring, and Example 3 adopts an air ring + upper and lower rotating baffles. Both are temperature distribution diagrams of the powder rod along the longitudinal direction when the powder rod diameter is 245 mm. Since the air ring can stabilize the reaction gas flow ejected from the blowtorch better than the glass cover and alleviate the chimney effect, the temperature on the powder rod in Example 1 is more uniform than that in Comparative Example 1; the temperature distribution is more uniform when the upper and lower rotating baffles are added.

Claims (27)

A deposition system for a quartz glass cylinder includes a deposition chamber, in which an upper and a lower rotating chuck are arranged, and blowtorches spaced up and down are arranged corresponding to the upper and lower rotating chucks, the upper and lower rotating chucks or the blowtorches are connected to an up and down moving device, one side of the deposition chamber is connected to an air inlet chamber, and the other side of the deposition chamber is connected to an exhaust chamber, characterized in that the blowtorch includes a raw gas nozzle and a fuel gas nozzle, an air ring nozzle is arranged at the outermost circle of the blowtorch nozzle, and the air ring nozzle is connected to a temperature-adjustable gas source. The deposition system for a quartz glass cylinder according to claim 1 is characterized in that a raw material gas nozzle is arranged in the middle of the blowtorch, the raw material gas nozzle comprises a central hole raw material gas nozzle and 1 to 3 layers of annular raw material gas nozzles surrounding the central hole raw material gas nozzle, and the raw material gas nozzle is connected to a raw material gas source. The quartz glass cylinder deposition system according to claim 2 is characterized in that the 1 to 3 layers of annular raw material gas nozzles are simultaneously connected to the inert gas source through a conversion valve. The deposition system of a quartz glass cylinder according to claim 1 or 2 is characterized in that the fuel gas nozzle is an annular fuel gas nozzle, which is arranged on the periphery of the raw gas nozzle, the annular fuel gas nozzle includes a hydrogen nozzle and an oxygen nozzle, the hydrogen nozzle and the oxygen nozzle are respectively arranged in 1 to 2 layers, and the fuel gas nozzle is connected to a fuel gas source. The quartz glass cylinder deposition system according to claim 1 or 2 is characterized in that an annular inert gas nozzle is provided between the raw gas nozzle and the fuel gas nozzle, and the annular inert gas nozzle is connected to the inert gas source. The deposition system of a quartz glass cylinder according to claim 1 or 2 is characterized in that the gas ring nozzle is arranged on the periphery of the fuel gas nozzle, the gas ring nozzle is composed of annular pores or closely spaced annular small holes, the gas ring nozzle is arranged in 1 to 2 layers, and the gas ring nozzle sprays gas to form a cylindrical air curtain, which covers the combustion raw material reaction gas in the cylindrical air curtain. The deposition system for a quartz glass cylinder according to claim 2 is characterized in that the raw material gas nozzle arranged in the middle of the blowtorch is a movable raw material gas nozzle, and the rear end of the movable raw material gas nozzle is connected to a rotating support mechanism, and the rotating support mechanism drives the movable raw material gas nozzle to rotate slowly. The deposition system for a quartz glass cylinder according to claim 7 is characterized in that the movable raw material gas nozzle is in the shape of a circular shaft, and an annular pore is formed with the inner hole of the burner body through the connection support of the rotating support mechanism, and the annular pore constitutes an annular inert gas nozzle. The quartz glass cylinder deposition system according to claim 1 or 2, characterized in that the blowtorch is made of metal or alloy. The quartz glass cylinder deposition system according to claim 1 or 2, characterized in that the upper and lower rotating clamps An upper and a lower rotating baffle are correspondingly arranged on the disk. The deposition system for a quartz glass cylinder according to claim 1 or 2 is characterized in that the air inlet chamber is located on the back side of the blowtorch, the front of the air inlet chamber is connected to the deposition chamber, the back of the air inlet chamber is connected to the sub-air inlet chambers separated up and down, and a heating device is provided at the air inlet of each sub-air inlet chamber for heating the incoming gas. The quartz glass cylinder deposition system according to claim 11 is characterized in that the air inlet of the sub-air inlet chamber is connected to the gas filter chamber, and a gas filter is provided in the gas filter chamber. The deposition system for a quartz glass cylinder according to claim 11 is characterized in that the exhaust chamber is located on the front side of the blowtorch, the front of the exhaust chamber is connected to the deposition chamber, the back of the exhaust chamber is connected to a sub-exhaust chamber separated into upper and lower parts, an air volume regulating valve is connected in series at the air outlet of each sub-exhaust chamber to adjust the flow rate of the extracted gas, and the air outlet of the sub-exhaust chamber is connected to the exhaust duct. The quartz glass cylinder deposition system according to claim 13 is characterized in that 6 to 12 sub-air inlet chambers are arranged above and below the air inlet chamber, and 6 to 12 sub-air exhaust chambers are arranged above and below the air exhaust chamber. The quartz glass cylinder deposition system according to claim 12 is characterized in that the exhaust duct is connected to an exhaust gas recovery duct, an exhaust gas recovery pump is installed in the exhaust gas recovery duct, and the other end of the exhaust gas recovery duct is connected to the gas filter chamber, so that part of the heat of the exhaust gas can be recovered. The quartz glass cylinder deposition system according to claim 1 or 2 is characterized in that the side walls on both sides of the deposition chamber are provided with guide fin devices that can swing up and down. The deposition system for a quartz glass cylinder according to claim 16 is characterized in that the guide fin device includes guide fins hinged to the side wall and arranged in parallel and spaced relation, the outer ends of the guide fins are hinged to an up and down movable rocker, and the up and down movable rocker is connected to a reciprocating drive mechanism. A method for depositing a quartz glass cylinder, using any deposition system as described in claims 1 to 17, firstly clamping a deposition target rod on upper and lower rotating chucks, opening an air inlet chamber and an air exhaust chamber, heating the air inlet gas and adjusting the air exhaust volume, so that the deposition chamber reaches a preset temperature range and air pressure range, Then, the upper and lower rotating chucks are turned on to drive the deposition target rod to rotate, and the up and down moving device is turned on to make the upper and lower rotating chucks and the blowtorch move up and down relatively, and the blowtorch is ignited to spray the raw material gas, fuel gas and inert gas and burn them together to generate silicon dioxide reactants that are deposited on the periphery of the target rod. The feature of the invention is that the air ring nozzle of the blowtorch sprays a cylindrical air curtain heating gas, and the temperature of the heating gas sprayed by each blowtorch is automatically adjusted according to the temperature feedback of the spraying area, so that the temperature of the upper and lower deposition areas of the target rod tends to be consistent, and the blowtorch continues to spray until the deposition is completed. The method for depositing a quartz glass cylinder according to claim 18, characterized in that the temperature of the gas ejected from the gas ring nozzle is in the range of 25 to 500°C, and the flow rate of the gas is in the range of 0.3 to 40 m/s, which can protect the reaction area of the silicon dioxide by about The silicon dioxide particles generated from the blowtorch nozzle to the powder rod are all in the gas field of the stable airflow. The method for depositing a quartz glass cylinder according to claim 18 or 19 is characterized in that as the diameter of the target rod deposition gradually increases, 1 to 3 layers of annular raw material gas nozzles surrounding the central hole raw material gas nozzle are opened layer by layer on the basis of first opening the central hole raw material gas nozzle, and the injection amount of the raw material gas is gradually increased, and at the same time, the second layer of fuel gas nozzles is opened, and the injection amount of the fuel gas is gradually increased to form a coaxial jet flame. The method for depositing a quartz glass cylinder according to claim 20 is characterized in that the attenuation formula of the axial velocity of the coaxial jet flame is:
in
_Qi is the mass flow rate of the i-th group of jets in kg/s, _pi is the momentum flux of the i-th group of jets in kg·m/s ² , a＝0.076, b＝0.147, _um is the center jet velocity, u _o is the center jet initial velocity, do _is the corresponding diameter, ρ is the gas density, x is the distance from the material pipe mouth, The central jet velocity um reaching 30mm from the deposition target surface _is between 15 and 90m/s. The method for depositing a quartz glass cylinder according to claim 18 or 19 is characterized in that when the deposition is stable, the temperature at the bottom is low and the temperature at the top is high, and the temperature difference maintains a stable trend, and heat compensation is performed by injecting gas through a gas ring, or by injecting gas through a gas ring in combination with upper and lower rotating baffles, and the compensation mechanism is as follows: the length of the target rod deposition area is L, and the length x (corresponding to the position of the blowtorch) is selected upwards from the lowest end of the target rod as the starting point: ①x<0.6L, heat compensation formula:
Q complement = e*x ² -f*x+g Where, Qcompensation is the heat to be compensated, in kw; e = 6*10 ^-06 ～ 9*10 ^-06 ; f = 0.0366～0.0443; g = 57.708～59.055 ②L>x≥0.6L, heat compensation: Qcompensation＝0. The method for depositing a quartz glass cylinder according to claim 22, characterized in that when x<0.6L, only the gas ring performs thermal compensation on the temperature, and the heat compensation formula is:
Q complement = 9*10 ^-06 x ² -0.0443x+57.708 The method for depositing a quartz glass cylinder according to claim 22, characterized in that when x<0.6L, the gas ring + upper and lower rotating baffles provide thermal compensation for the temperature, and the heat compensation formula is:
Q complement = 6*10 ^-06 x ² -0.0366x+59.055 The method for depositing a quartz glass cylinder according to claim 18 or 19 is characterized in that the sub-air inlet chamber of the air inlet chamber automatically adjusts the air inlet temperature according to the temperature feedback of the separated deposition area, so that the temperature of the upper and lower deposition areas of the target rod is further consistent; the temperature compensation gas of the air inlet chamber and the temperature compensation gas of the air ring nozzle of the blowtorch are used together to ensure that the temperature of the powder rod surface is consistent during the entire deposition process and is not affected by the deposition time and the upper and lower parts of the deposition; at the initial stage of deposition, the temperature of the rotating target rod and the deposition chamber approaches room temperature, the air inlet chamber temperature is compensated to 400°C, the upper and lower air inlet chambers are the same, and the gas temperature of the upper air ring nozzle of the blowtorch is 80 0℃, keeping the surface temperature of the entire target rod greater than 500℃ and less than 1200℃; in the middle stage of deposition, the occurrence of deposition reaction causes the cavity temperature to rise, the chimney effect is obvious, the temperature compensation of the air inlet cavity decreases from 400℃ downward, and the temperature gradually decreases from bottom to top. At the same time, the temperature compensation gas ring gradually decreases the temperature, keeping the surface temperature of the entire target rod greater than 500℃ and less than 1200℃; at the end of deposition, the temperature compensation of the air inlet cavity and the temperature compensation gas ring on the blowtorch first heat up to keep the surface temperature of the entire target rod greater than 500℃ and less than 1200℃, and then gradually cool down to anneal the powder rod, and the temperature difference of the deposition process is maintained at ±50℃. The method for depositing a quartz glass cylinder according to claim 18 or 19 is characterized in that the sub-exhaust chamber of the exhaust chamber adjusts the flow rate of the extracted gas through an air volume regulating valve according to the injection amount of the raw material gas and the deposition amount, thereby ensuring that the deposited dust is extracted in time. The method for depositing a quartz glass cylinder according to claim 18 or 19 is characterized in that the exhaust gas recovery pump is turned on so that part of the exhaust gas is recovered to the gas filter chamber through the exhaust gas recovery pipeline, so that part of the heat of the exhaust gas is recovered.