Device and system for producing optical fiber preform based on industrial grade D4

Abstract

The utility model provides a device and a system for producing an optical fiber preform based on industrial grade D4. The device for producing the optical fiber preform based on the industrial grade D4 comprises a coarse treatment device, a fine treatment device, a low-boiling-point impurity treatment device and a high-boiling-point treatment device which are communicated in sequence, an anion-cation exchange resin membrane and a molecular sieve are arranged in the fine treatment device to remove metal ions and anion impurities in the D4 liquid, the low-boiling-point impurity treatment device is used for separating low-boiling-point impurities in the D4 liquid, the high-boiling-point treatment device is used for separating high-boiling-point impurities in the D4 liquid, and a gas outlet of the high-boiling-point treatment device is communicated with the combustor. According to the device provided by the utility model, the existing commercially available industrial grade D4 is utilized, the adverse effect of gel on deposition production equipment in the D4 gasification process is relieved, the tolerance requirement of the deposition equipment on the purity of the raw material D4 is increased, and the production cost of the optical fiber preform can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber preform manufacturing technology, and in particular to an apparatus and system for producing optical fiber preforms based on industrial-grade D4. Background Technology

[0002] Organosilanes and silicon tetrachloride (SiCl4) are currently the two key raw materials for the mainstream production of large-size optical fiber preforms. The preparation of SiO2 preforms using the high-temperature pyrolysis process of SiCl4 generates a large amount of corrosive substances such as Cl2 and HCl gases, requiring a large amount of equipment to treat the exhaust gases.

[0003] Compared to using SiCl4 as the main raw material to prepare SiO2 preforms, using D4 as a raw material to produce optical fiber preforms not only has a high SiO2 generation efficiency (the generation efficiency per unit weight is almost three times that of SiCl4), but is also more environmentally friendly (the main byproducts are CO2 and H2O, with no harmful gases such as HCl and Cl2 produced), requires less investment in waste gas treatment, and fundamentally reduces the chloride content in the synthesized silicon glass.

[0004] Industrial D4 is mostly prepared from dimethyldichlorosilane hydrolysate through a cracking and rearrangement reaction. The preparation process involves numerous side reactions, resulting in industrial-grade D4 products containing impurities of light and heavy components such as D3 (hexamethylcyclotrisiloxane), D5 (decamethylcyclopentasiloxane), and D6 (dodecylmethylcyclohexasiloxane), as well as metal compound impurities and moisture.

[0005] Tracking the preparation of SiO2 preforms using D4 of different purities as raw materials revealed that D4 purity, water content, and metal impurity content significantly affect the stability and consistency of the deposition process. Low-purity D4 as a raw material causes uneven SiO2 preform deposition and defects, while also accelerating the ring-opening polymerization of D4 in the transport pipeline, shortening the service life of the deposition equipment and increasing equipment maintenance.

[0006] Research progress on octamethylcyclotetrasiloxane for optical fiber preforms (Pu Yunping) Literature research shows that: the impurity content in D4 directly affects the ring-opening polymerization of D4 vapor in the delivery pipeline during the deposition process, forming gel that blocks the delivery pipeline and reduces the deposition efficiency.

[0007] Commercially available industrial-grade D4 is mainly used as a raw material for silicone rubber (the D4 content is generally around 99%, containing metal impurity ions and high and low boiling point impurities (D3 / D5 / D6 and other cyclic silane impurities, which have an extremely adverse effect on the stability of the deposition process of optical fiber preforms prepared by the VAD / OVD method and the quality of the optical fiber preforms), and cannot directly meet the requirements for use as optical fiber preforms.

[0008] Using high-purity D4 as raw material can significantly reduce the blockage of D4 gel in the delivery pipeline during the deposition process, thus reducing maintenance downtime of the deposition equipment. D4 accounts for approximately 50% of the cost in the production of optical fiber preforms; excessively high purity requirements mean a substantial increase in the procurement cost of D4 raw materials. Furthermore, considering that the storage, transportation, and delivery of D4 inevitably introduce new impurities (e.g., the use of stainless steel in loose pipelines inevitably introduces metal compounds), even if the purchased raw materials have high D4 purity, the impurity content delivered to the deposition equipment may be far higher than the factory-grade D4 product.

[0009] Therefore, how to utilize existing commercially available industrial-grade D4, mitigate the adverse effects of gel on deposition equipment during D4 vaporization, and increase the tolerance of deposition equipment to the purity of raw material D4 is of great significance for reducing the production cost of optical fiber preforms. Utility Model Content

[0010] The main objective of this invention is to provide an apparatus and system for producing optical fiber preforms based on industrial-grade D4, which aims to utilize industrial-grade D4 to produce optical fiber preforms and mitigate the adverse effects of gel on deposition equipment during D4 vaporization.

[0011] To achieve the above objectives, this utility model provides an apparatus for producing optical fiber preforms based on industrial-grade D4, comprising a coarse processing device, a fine processing device, a low-boiling-point impurity treatment device, and a high-boiling-point treatment device connected in sequence, wherein...

[0012] The coarse treatment device is used to reduce the liquid water content in D4. The fine treatment device is equipped with anion and cation exchange resin membranes and molecular sieves to remove metal ions and anion impurities from the D4 liquid. The low-boiling-point impurity treatment device is used to separate low-boiling-point impurities from the D4 liquid. The high-boiling-point treatment device is used to separate high-boiling-point impurities from the D4 liquid. The gas outlet of the high-boiling-point treatment device is connected to the burner.

[0013] Preferably, the device for producing optical fiber preforms based on industrial-grade D4 further includes a filter device for filtering solid gel particles connected to the gas outlet of the high-boiling-point treatment device. The outlet of the filter device is connected to a conveying pipe, and the outlet of the conveying pipe is connected to a burner. The filter device is equipped with a metal mesh filter and an oil film adsorbent, and a weighing device is also provided.

[0014] Preferably, the conveying pipe is equipped with a heating device to ensure that the temperature of the D4 vapor inside is constant, and the conveying pipe is connected to a high-temperature carrier gas supply device to increase the D4 vapor throughput rate.

[0015] Preferably, the coarse treatment device, the fine treatment device, the low-boiling-point impurity treatment dust hood, and the high-boiling-point treatment device are all pressure pipeline containers.

[0016] Preferably, the pressure pipeline container is wrapped with an electric heating wire and an insulation layer, and each pressure pipeline container is equipped with a pressure control device to regulate its internal pressure.

[0017] Preferably, the device for producing optical fiber preforms based on industrial-grade D4 further includes a high-temperature water vapor collection tank connected to the gas outlet of the coarse treatment device. The high-temperature water vapor collection tank is used to collect high-temperature water vapor from the D4 liquid obtained after treatment by the coarse treatment device.

[0018] Preferably, the apparatus for producing optical fiber preforms based on industrial-grade D4 further includes a low-boiling-point impurity collection tank connected to the gas outlet of the low-boiling-point impurity treatment device and a condensation tank connected to the outlet of the low-boiling-point impurity collection tank for liquefying the low-boiling-point impurities. The low-boiling-point impurity collection tank is used to collect the low-boiling-point impurities that volatilize in the low-boiling-point impurity treatment device.

[0019] Preferably, the device for producing optical fiber preforms based on industrial-grade D4 further includes a high-boiling-point collection tank connected to the liquid outlet of the high-boiling-point treatment device. A one-way valve is installed between the high-boiling-point collection tank and the high-boiling-point treatment device. The high-boiling-point collection tank is used to collect unvaporized high-boiling-point impurities and gel particles generated during the vaporization of D4 in the high-boiling-point treatment device.

[0020] Preferably, the high-temperature steam collecting tank, the low-boiling-point impurity collecting tank, and the high-boiling-point collecting tank are all equipped with weighing devices.

[0021] This utility model also proposes a system for producing optical fiber preforms based on industrial-grade D4, including the aforementioned device for producing optical fiber preforms based on industrial-grade D4, and further including a burner, which is connected to the gas outlet of the high-boiling-point treatment device of the device for producing optical fiber preforms based on industrial-grade D4.

[0022] The device for producing optical fiber preforms based on industrial-grade D4 fiber proposed in this utility model has the following beneficial effects:

[0023] 1. Compared with existing D4 purification devices, the manufacturing and production costs of this utility model are low;

[0024] 2. This utility model can effectively reduce the water content in D4 liquid through a coarse treatment device, and the deposition process is not affected by the water content of the incoming D4 or the moisture introduced during transportation and transfer.

[0025] 3. This utility model can effectively reduce the content of metal ions and anions (mainly chloride ions) in D4 feed material through a fine treatment device, reduce the influence of metal ions on the ring-opening polymerization to form gel during the D4 evaporation process, and greatly increase the start-up efficiency of the deposition equipment.

[0026] 4. This utility model separates high and low boiling point organosiloxane cyclic impurities (D3 has an extremely fast ring-opening polymerization gelation rate, and D5 / D6 is not easy to vaporize) in D4 through a low boiling point impurity treatment device and a high boiling point treatment device, further reducing the gel generated by D4 liquid during evaporation, as well as the high boiling point droplets remaining in D4 vapor (affecting deposition stability).

[0027] 5. This utility model processes impurity ions and high and low boiling point impurities in the D4 feed material online, ensuring that the D4 evaporator in the deposition pipeline is in a high-purity state, does not produce gel, and the delivery pipe can be maintained and replaced for a long time. The SiO2 preform obtained by stable combustion is of excellent quality, which greatly improves the efficiency of the deposition equipment and the deposition quality.

[0028] 6. This utility model greatly increases the tolerance of the deposition system to the quality fluctuation of the incoming D4 by processing impurity ions and high and low boiling point impurities in the D4 material online. Low purity industrial grade D4 (content 99%~99.9%) can be used directly without affecting the quality of the deposited SiO2 preform, reducing the operation cycle of the deposition equipment, and greatly reducing the cost of D4 raw materials in the production process of optical fiber preforms. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the device for producing optical fiber preforms based on industrial-grade D4 according to this utility model.

[0030] Figure 2 This is a schematic diagram of the low-boiling-point impurity treatment device in the device for producing optical fiber preforms based on industrial-grade D4 according to this utility model.

[0031] In the diagram, 1-coarse treatment device, 2-high temperature steam collection tank, 3-fine treatment device, 31-cation exchange resin membrane, 32-cation exchange resin membrane, 33-molecular sieve, 34-inlet pipe, 35-drain outlet, 36-outlet pipe, 4-low boiling point impurity treatment device, 5-low boiling point impurity collection tank, 6-high boiling point treatment device, 7-high boiling point collection tank, 8-filtration device, 9-transfer pipe, 10-burner, 11-condenser.

[0032] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0034] It should be noted that in the description of this utility model, the terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] This invention proposes a device for producing optical fiber preforms based on industrial-grade D4.

[0036] Reference Figure 1 and Figure 2 In this preferred embodiment, an apparatus for producing optical fiber preforms based on industrial-grade D4 includes a coarse processing device 1, a fine processing device 3, a low-boiling-point impurity treatment device 4, and a high-boiling-point treatment device 6 connected in sequence.

[0037] The coarse treatment device 1 is used to reduce the water content in the liquid D4. The fine treatment device 3 is equipped with anion and cation exchange resin membranes and molecular sieves to remove metal ions and anion impurities from the liquid D4. The low boiling point impurity treatment device 4 is used to separate low boiling point impurities from the liquid D4. The high boiling point treatment device 6 is used to separate high boiling point impurities from the liquid D4.

[0038] Industrial grade D4 refers to D4 with a D4 mass fraction of 99% to 99.9%. (Refer to...) Figure 2 The fine treatment device 3 contains, from top to bottom, a cation exchange resin membrane 31, a cation exchange resin membrane 32, and a molecular sieve 33. The relative order of the exchange membranes and molecular sieves can be adjusted according to the actual usage effect. The fine treatment device 3 is equipped with an inlet pipe 34, a drain port 35, and an outlet pipe 36. The outlet pipe 36 is connected to the low-boiling-point impurity treatment device 4. The cation exchange resin membranes 31, 32, and 33 can all be replaced periodically; they are inexpensive and can be purchased directly. After treatment by the fine treatment device 3, the content of major metal ions and anionic impurities in liquid D4 is significantly reduced.

[0039] Furthermore, the device for producing optical fiber preforms based on industrial-grade D4 also includes a filter device 8 for filtering solid gel particles, which is connected to the gas outlet of the high-boiling-point treatment device 6. The outlet of the filter device 8 is connected to a conveying pipe 9, and the outlet of the conveying pipe 9 is connected to a burner 10. The filter device 8 is equipped with a metal mesh filter and an oil film adsorbent, and a weighing device is also provided.

[0040] The filter device 8 is used to collect the D4 vapor after it is vaporized by the high-boiling-point treatment device 6. Its temperature is controlled at 170℃~220℃. The filter device 8 is used to filter out solid gel particles that may be present in the D4 vapor. The filter device 8 is equipped with a precision weighing instrument, which can periodically monitor the impurity content in the vapor. The vapor passing through the filter device 8 mainly becomes high-purity D4 vapor, with a purity of over 99.9%. This can effectively reduce the instability of the D4 vapor reaction in the end burner 10 and obtain high-quality SiO2 preforms.

[0041] Furthermore, the delivery pipe 9 is equipped with a heating device to ensure a constant temperature of the D4 vapor inside. The delivery pipe 9 is connected to a high-temperature carrier gas supply device to increase the D4 vapor throughput. The heating device can be an electric heating device or an oil bath heating device. The temperature of the heating device is controlled between 200℃ and 220℃. The high-purity, high-temperature carrier gas is N2 or argon. The carrier gas can increase the D4 vapor throughput, and its heating temperature before mixing with the D4 vapor is maintained between 195℃ and 210℃, with a flow rate set within the range of 10 to 50 slm.

[0042] Specifically, in this embodiment, the coarse treatment device 1, the fine treatment device 3, the low-boiling-point impurity treatment dust hood, and the high-boiling-point treatment device 6 are all pressure pipeline containers. The outside of the pressure pipeline container is wrapped with an electric heating wire and an insulation layer. Each pressure pipeline container is equipped with a pressure control device to regulate its internal pressure. The inner diameter of the stainless steel container of the coarse treatment device 1 is 20 cm to 40 cm.

[0043] Furthermore, this apparatus for producing optical fiber preforms based on industrial-grade D4 also includes a high-temperature water vapor collection tank 2 connected to the gas outlet of the coarse treatment unit 1. The high-temperature water vapor collection tank 2 is used to collect high-temperature water vapor from the D4 liquid obtained after treatment by the coarse treatment unit 1. The high-temperature water vapor collection tank 2 is connected to the coarse treatment unit 1 via a stainless steel pipe with a diameter of 20mm~40mm. The high-temperature water vapor collection tank 2 has a weighing device to detect the collected water content in real time.

[0044] Furthermore, the apparatus for producing optical fiber preforms based on industrial-grade D4 also includes a low-boiling-point impurity collection tank 5 connected to the gas outlet of the low-boiling-point impurity treatment device 4, and a condenser 11 connected to the outlet of the low-boiling-point impurity collection tank 5 for liquefying the low-boiling-point impurities. The low-boiling-point impurity collection tank 5 is used to collect the low-boiling-point impurities that volatilize in the low-boiling-point impurity treatment device 4.

[0045] Furthermore, the device for producing optical fiber preforms based on industrial-grade D4 also includes a high-boiling-point collection tank 7 connected to the liquid outlet of the high-boiling-point treatment device 6. A one-way valve is installed between the high-boiling-point collection tank 7 and the high-boiling-point treatment device 6. The high-boiling-point collection tank 7 is used to collect unvaporized high-boiling-point impurities and gel particles generated during the vaporization of D4 in the high-boiling-point treatment device 6.

[0046] The high-temperature steam collection tank 2, the low-boiling-point impurity collection tank 5, and the high-boiling-point collection tank 7 are all equipped with weighing devices.

[0047] The working principle of this device for producing optical fiber preforms based on industrial-grade D4 is as follows.

[0048] The coarse treatment unit 1 has heating and pressure control functions, as well as filtering particulate impurities. The water content of the liquid after treatment by the coarse treatment unit 1 can be reduced to below 50 ppm, effectively reducing the impact of water content on the deposition process. The high-temperature steam collection tank 2 collects the water and some low-boiling-point impurities that may be present in the D4 material separated by the coarse treatment unit 1. The fine treatment unit 3 treats the metallic impurities in the D4 liquid, and the content of the main metal ions and anions in the D4 liquid is significantly reduced after treatment. The low-boiling-point impurity treatment unit 4 further separates the low-boiling-point impurities (mainly D3) in the D4 liquid. By controlling the internal pressure (0.02~0.06 MPa) and temperature (90~130℃) of the unit, the low-boiling-point impurities are separated. After vacuum fractionation by the fine treatment unit 3, the content of low-boiling-point impurities (D3) in the D4 liquid is further reduced to below 100 ppm. The low-boiling-point impurity collection tank 5 receives the low-boiling-point impurities fractionated from the refining unit 3. It is located at the top of the refining unit 3 and is unidirectionally connected to it, and has a weight monitoring unit. By monitoring the weight change of the low-boiling-point impurity collection tank 5, the fractionation effect of the low-boiling-point impurity treatment unit 4 can be monitored. The low-boiling-point impurity collection tank 5 has a quick-release structure for convenient periodic processing of the collected impurities. The high-boiling-point treatment unit 6 is used to fractionate D4 and high-boiling-point impurities. Its temperature (170~220℃) and pressure (0.02~0.06Mpa) are controlled to ensure complete vaporization of D4. Unvaporized high-boiling-point impurities (mainly D5 and D6, which greatly affect the stable combustion of D4 at the downstream end) and gel particles generated during the ring-opening polymerization of D4 during vaporization phase change fall to the bottom of the high-boiling-point treatment unit 6 due to gravity. The high-boiling-point collection tank 7 is used to collect liquid and gel impurities falling from the high-boiling-point treatment device 6. The high-boiling-point collection tank 7 is located at the bottom of the high-boiling-point treatment device 6 and is unidirectionally connected to it. It is equipped with a weighing device inside, which can monitor the amount of liquid and solid impurities collected in real time. It can be quickly disassembled for convenient regular maintenance.

[0049] The following details the usage of this device for producing optical fiber preforms based on industrial-grade D4. D4 with purities of 99.01%, 99.50%, and 99.92% was pumped into the device, and the compositional changes of the D4 vapor after liquefaction in the front delivery pipe 9 of the burner 10 and the degree of clogging of the filter device 8 were analyzed and tracked after processing by the above device (monitored by weight and maintenance cycle).

[0050] The flow rate is set to 300~500g / min via the flow controller MFC and fed into the coarse treatment device 1. The coarse treatment device 1 is a pressure pipeline container with an inner diameter of 20cm, encased in an electric heating wire and insulation layer, and equipped with a pressure control unit to automatically control the pressure inside the container. The temperature of the coarse treatment device 1 is set to 120℃, and the pressure is controlled at 0.03MPa to treat the moisture in the incoming material D4. The moisture in the incoming material is vaporized into high-temperature water vapor at high temperature and rises to the high-temperature water vapor collection tank 2. The high-temperature water vapor collection tank 2 is connected to the coarse treatment device 1 in one direction via a stainless steel pipe with an inner diameter of 5cm (the steam cannot return to the coarse treatment device 1).

[0051] After water separation, the D4 liquid enters the refining device 3, a pipe container with an inner diameter of 15 cm. Inside, from the direction of D4 liquid flow, multiple layers of cation exchange resin membrane, anion exchange resin membrane, and porous molecular sieve are sequentially installed to adsorb and remove metal ions and Cl ions from the incoming D4. The purified D4 liquid then enters the low-boiling-point impurity treatment device 4, a pressure pipe container with an inner diameter of 10 cm, encased in an electric heating wire and insulation layer, and equipped with a pressure control device to automatically maintain the pressure inside the pipe container. The temperature inside the refining device 3 is set to 145℃ and the pressure to 0.03 MPa. To ensure sufficient vaporization of low-boiling-point D3 in the low-boiling-point impurity treatment device 4, the D4 liquid is sprayed from the bottom of the device into the low-boiling-point impurity treatment device 4. The low-boiling-point impurity collection tank 5 collects the vaporized D3 vapor and condenses it back into liquid in its attached condenser 11 for easy discharge.

[0052] After low-boiling-point impurities are separated by the low-boiling-point impurity treatment device 4, the relatively high-boiling-point impurities, such as D4, remain in a liquid state and are sprayed from the bottom of the high-boiling-point treatment device 6 into the high-boiling-point treatment device 6. The high-boiling-point treatment device 6 is a pressure pipeline container with an inner diameter of 8 cm, wrapped with an electric heating wire and an insulation layer, and equipped with a pressure control device to automatically monitor the pressure inside the pipeline container. The temperature inside the high-boiling-point treatment device 6 is set to 205℃ and the pressure to 0.03 MPa, allowing D4 to fully vaporize. D5 / D6, etc., due to their relatively high boiling points, are not vaporized and enter the high-boiling-point collection tank 7 located at the bottom of the high-boiling-point treatment device 6 under the influence of gravity. In addition, gel particles generated during the vaporization of D4 also fall into the high-boiling-point collection tank 7 due to their weight. The high-boiling-point collection tank 7 is designed to be detachable and is periodically disassembled and cleaned to remove residual liquid and gel based on weight detection data.

[0053] D4 vapor is separated by the high-boiling-point treatment device 6, filtered by the filter device 8, and then enters the conveying pipe 9. Simultaneously, high-purity inert gas Ar (99.99% purity) is introduced into the conveying pipe 9 and sent to the burner 10. The filter device 8 intercepts and filters the gel particles carried out by the gas flow during the D4 vaporization process. The D4 vapor filtered by the filter device 8 then enters the burner 10 for combustion, producing SiO2 deposited into a preform.

[0054] Table 1 shows the component analysis data of D4 samples taken from point 9 of the conveying pipe after liquefaction of 99% pure D4 material processed by this device:

[0055]

[0056] Table 2 shows the component analysis data of D4 sample taken from point 9 of the conveying pipe after liquefaction of the incoming material D4 with a purity of 99.5% after processing by this device:

[0057]

[0058] Table 3 shows the component analysis data of D4 samples taken from point 9 of the conveying pipe after liquefaction and processing by the device of this invention, with a purity of 99.9%.

[0059]

[0060] Table 4 shows the maintenance cycle, deposition efficiency, and SiO2 preform quality of three types of incoming D4 with different purities, directly vaporized at 205℃ and transported to burner 10 via conveying pipe 9 without processing by the device of this invention.

[0061] Table 4

[0062]

[0063] Table 5 shows the maintenance cycle, deposition efficiency, and SiO2 preform quality of three types of D4 raw materials processed by the method and apparatus described in this invention, directly vaporized at 205℃, and then transported to the burner 10 via the conveying pipe 9 for combustion.

[0064] Table 5

[0065]

[0066] As shown in Tables 1 to 5, the use of this device increases the tolerance of the deposition equipment to the purity of the incoming D4 material, allowing low-purity (industrial-grade D4) materials to be directly used in the VAD / OVD method for producing optical fiber preforms. This greatly reduces the impact of fluctuations in the quality of the incoming D4 material during the production of optical fiber preforms and improves the operating efficiency of the deposition equipment.

[0067] The device for producing optical fiber preforms based on industrial-grade D4 fiber proposed in this utility model has the following beneficial effects:

[0068] 1. Compared with existing D4 purification devices, the manufacturing and production costs of this utility model are low;

[0069] 2. This utility model can effectively reduce the water content in liquid D4 through the coarse treatment device 1, and the deposition process is not affected by the water content of the incoming D4 or the moisture introduced during transportation and transfer.

[0070] 3. This utility model can effectively reduce the content of metal ions and anions (mainly chloride ions) in the D4 feed material through the fine treatment device 3, thereby reducing the influence of metal ions on the ring-opening polymerization to form gel during the D4 evaporation process and greatly increasing the start-up efficiency of the deposition equipment.

[0071] 4. This utility model separates high and low boiling point organosiloxane cyclic compounds (D3 has an extremely fast ring-opening polymerization gelation rate, and D5 / D6 is not easy to vaporize) in D4 through a low boiling point impurity treatment device 4 and a high boiling point treatment device 6, further reducing the gel generated by D4 liquid during evaporation and the high boiling point droplets remaining in D4 vapor (affecting deposition stability).

[0072] 5. This utility model processes impurity ions and high and low boiling point impurities in the D4 feed material online, ensuring that the D4 evaporator in the deposition pipeline is in a high-purity state and does not produce gel. The conveying pipe 9 can be maintained and replaced for a long time, and the SiO2 preform obtained by stable combustion is of excellent quality, which greatly improves the efficiency of the deposition equipment and the deposition quality.

[0073] 6. This utility model greatly increases the tolerance of the deposition system to the quality fluctuation of the incoming D4 by processing impurity ions and high and low boiling point impurities in the D4 material online. Low purity industrial grade D4 (content 99%~99.9%) can be used directly without affecting the quality of the deposited SiO2 preform, reducing the operation cycle of the deposition equipment, and greatly reducing the cost of D4 raw materials in the optical fiber preform production process.

[0074] This invention further proposes a system for producing optical fiber preforms based on industrial-grade D4.

[0075] In this preferred embodiment, a system for producing optical fiber preforms based on industrial-grade D4 includes an apparatus for producing optical fiber preforms based on industrial-grade D4, and a burner connected to the gas outlet of a high-boiling-point treatment device of the apparatus for producing optical fiber preforms based on industrial-grade D4. The specific structure and beneficial effects of the apparatus for producing optical fiber preforms based on industrial-grade D4 are described in the above embodiments and will not be repeated here.

[0076] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An apparatus for producing optical fiber preforms based on industrial-grade D4, characterized in that, It includes a coarse treatment unit, a fine treatment unit, a low-boiling-point impurity treatment unit, and a high-boiling-point treatment unit connected in sequence, wherein, The coarse treatment device is used to reduce the liquid water content in D4. The fine treatment device is equipped with anion and cation exchange resin membranes and molecular sieves to remove metal ions and anion impurities from the D4 liquid. The low-boiling-point impurity treatment device is used to separate low-boiling-point impurities from the D4 liquid. The high-boiling-point treatment device is used to separate high-boiling-point impurities from the D4 liquid. The gas outlet of the high-boiling-point treatment device is connected to the burner.

2. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 1, characterized in that, It also includes a filter device for filtering solid gel particles that is connected to the gas outlet of the high-boiling-point treatment device. The outlet of the filter device is connected to a conveying pipe, and the outlet of the conveying pipe is connected to a burner. The filter device is equipped with a metal mesh filter and an oil film adsorbent, and a weighing device is also provided.

3. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 2, characterized in that, The conveying pipe is equipped with a heating device to ensure that the temperature of the D4 vapor inside is constant, and the conveying pipe is connected to a high-temperature carrier gas supply device to increase the D4 vapor throughput rate.

4. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 1, characterized in that, The coarse treatment device, fine treatment device, low-boiling-point impurity treatment dust hood, and high-boiling-point treatment device are all pressure pipeline containers.

5. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 4, characterized in that, The pressure pipeline container is wrapped with an electric heating wire and an insulation layer on the outside, and each pressure pipeline container is equipped with a pressure control device to regulate its internal pressure.

6. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in any one of claims 1 to 5, characterized in that, It also includes a high-temperature water vapor collection tank connected to the gas outlet of the coarse treatment unit, which is used to collect high-temperature water vapor from the D4 liquid obtained after treatment by the coarse treatment unit.

7. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 6, characterized in that, It also includes a low-boiling-point impurity collection tank connected to the gas outlet of the low-boiling-point impurity treatment device, and a condenser connected to the outlet of the low-boiling-point impurity collection tank for liquefying the low-boiling-point impurities. The low-boiling-point impurity collection tank is used to collect the low-boiling-point impurities that volatilize in the low-boiling-point impurity treatment device.

8. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 7, characterized in that, It also includes a high-boiling-point collection tank connected to the liquid outlet of the high-boiling-point treatment device. A one-way valve is installed between the high-boiling-point collection tank and the high-boiling-point treatment device. The high-boiling-point collection tank is used to collect unvaporized high-boiling-point impurities and gel particles generated during the vaporization of D4 in the high-boiling-point treatment device.

9. The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in claim 8, characterized in that, The high-temperature steam collection tank, the low-boiling-point impurity collection tank, and the high-boiling-point collection tank are all equipped with weighing devices.

10. A system for producing optical fiber preforms based on industrial-grade D4, characterized in that, The apparatus for producing optical fiber preforms based on industrial-grade D4 as described in any one of claims 1 to 9 further includes a burner connected to the gas outlet of the high-boiling-point treatment device of the apparatus for producing optical fiber preforms based on industrial-grade D4.

Images