An outer vapor deposition double-shell device for optical fiber preform preparation

Abstract

The utility model relates to a kind of outer vapor deposition double-shell devices for optical fiber preform preparation, it is for the existing optical fiber preform manufacturing reaction kettle design is poor, it is more difficult to improve its monitoring and automation management with air high-efficiency filter, frequency conversion fan.The device includes an inner reaction kettle mainly for deposition and an outer shell body surrounding the inner reaction kettle, i.e., outer reaction kettle;Its main point is that the left and right sides of the inner reaction kettle are respectively provided with exhaust end and air inlet end, the exhaust end pipeline of left side is connected with external waste gas treatment device, the air inlet end of right side is installed with multiple diffusion screens, air high-efficiency filter is installed on the right side of outer shell body, while filtering out most impurities in air, the air amount entering equipment is adjusted by the control of frequency conversion fan.

Description

Technical Field

[0001] This utility model relates to a reaction vessel for the fabrication of optical fiber preforms, specifically an external vapor deposition double-shell device for the preparation of optical fiber preforms. Background Technology

[0002] Currently, the mainstream manufacturing processes for optical fiber preforms are VAD, OVD, MCVD, and PCVD. Among these, External Vapor Deposition (OVD) is generally used to produce the outer cladding to reduce the production cost of optical fiber preforms. The main chemical reactions in OVD are as follows: H2 + O2 → H2O; H2O + SiCl4 → SiO2 + HCl. To further reduce production costs, the number of deposition torches is commonly increased to improve production efficiency and lower costs. However, as products become larger, the requirements for equipment also increase. Simultaneously, with the increase in the number of torches, the heat generated by the flames also increases dramatically. If this increased heat cannot be effectively dissipated or cooled, it will place a significant burden on the equipment and may even damage it. Therefore, higher demands are placed on the spatial design and material requirements of the equipment. Existing optical fiber preform manufacturing processes and equipment include, for example, Chinese patent application number 201510289371.0, published on August 5, 2015, entitled "A Microwave Dehydration Device and Method for the Manufacturing Process of Optical Fiber Preforms"; and Chinese patent application number 201010504881.2, published on April 13, 2011, entitled "A Heat Treatment Method and Device for Optical Fibers". Currently, the commonly used multi-torch deposition method simply expands the reactor space, lengthening and enlarging the reactor to ensure sufficient heat release from the flame. Increased airflow and exhaust volume further reduce the exhaust gas temperature, minimizing its impact on the reactor. Furthermore, to reduce hydrochloric acid generated during OVD deposition, reactors are typically made of Hastelloy or nickel-molybdenum alloys. Some reactors are coated with high-temperature and corrosion-resistant coatings, which are relatively expensive. Therefore, simply enlarging the reactor not only increases equipment investment but also increases the difficulty of cleaning operations for personnel. Summary of the Invention

[0003] To overcome the aforementioned shortcomings, the purpose of this utility model is to provide a dual-shell external vapor deposition device for optical fiber preform fabrication, thereby solving the technical problems of suboptimal reactor structure design, high production costs, and difficulty in improving monitoring and automated management by integrating high-efficiency air filters and variable frequency fans in existing optical fiber preform fabrication processes. This objective is achieved through the following technical solution.

[0004] An external vapor deposition dual-shell device for optical fiber preform fabrication includes an inner reactor mainly used for deposition and an outer shell surrounding the inner reactor, i.e., the outer reactor. The key structural design features an exhaust end and an inlet end on the left and right sides of the inner reactor, respectively. The exhaust end on the left is connected to an external waste gas treatment device, and the inlet end on the right is equipped with a multi-layer diffuser. A high-efficiency air filter is installed on the right side of the outer shell. This filter removes most impurities from the air while the amount of air entering the device is adjusted by a variable frequency fan.

[0005] Therefore, this external vapor deposition dual-shell device is designed with a dual-shell structure. The reactor for deposition is located inside, and its size is slightly larger than the size of the product to be deposited. The left and right sides of the inner reactor are respectively equipped with an exhaust end and an air inlet end. The exhaust end on the left side is connected to an external waste gas treatment device, and the air inlet end on the right side is equipped with a multi-layer diffuser to facilitate a stable inflow of clean air without affecting the torch flame. The outer shell is a single outer shell, i.e., the outer reactor. A high-efficiency air filter is installed on the right side of the outer shell. The high-efficiency air filter removes most of the impurities in the air, and the air volume entering the equipment is adjusted by the control of a variable frequency fan. The high-efficiency air filter and the variable frequency fan in the outer shell ensure that the internal pressure of the outer shell is greater than the internal pressure of the inner reactor and greater than the external air pressure of the equipment. This ensures that toxic and harmful substances generated in the inner reactor will not overflow, and reduces the entry of external impurities into the inner reactor, thereby reducing the impact of impurities on product quality, improving product quality, and reducing production costs. Meanwhile, the external vapor deposition dual-shell device extends the service life of the equipment by reducing the outer surface temperature of the inner reactor, while the added outer shell device ensures the cleanliness of the inner reactor and improves product quality.

[0006] The diffuser mesh of the inner reactor is a corrosion- and oxidation-resistant diffuser mesh made of nickel-containing material, with a pore size of less than or equal to 1.5 mm. 2 The number of layers is limited to 3-6 layers, and the middle of the diffuser net has large holes to facilitate the installation of deposition torches.

[0007] The left side of the outer casing is provided with an overflow hole to facilitate the discharge of clean air. The opening and closing amplitude of the overflow hole is controlled by electrical control and the opening and closing amplitude of the overflow hole is controlled by monitoring the pressure difference between the internal pressure of the outer reactor and the external air pressure.

[0008] The air intake of the outer shell is controlled by a variable frequency fan, and the frequency of the fan is adjusted by monitoring the pressure difference between the inner and outer reactors.

[0009] This utility model has a reasonable structural design, is easy to use and operate, and is easy to promote and apply. In particular, it facilitates the improvement of automated monitoring of corresponding equipment. It is suitable for use as an external vapor deposition double-shell device for optical fiber preform preparation and for the improvement of similar products. Attached Figure Description

[0010] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention.

[0011] Attached figures and their names: 1. Inner reactor; 101. Diffuser; 102. Large pores; 2. Outer shell; 3. High-efficiency air filter; 4. Deposition torch. Implementation

[0012] The structure of this utility model will now be further described with reference to the accompanying drawings. For example... Figure 1 As shown, the external vapor deposition dual-shell device includes an inner reactor 1, mainly used for deposition, and an outer shell 2, i.e., the outer reactor, surrounding the inner reactor. The inner reactor has an exhaust end and an inlet end on its left and right sides, respectively. The exhaust end on the left is connected to an external waste gas treatment device, and the inlet end on the right is equipped with a multi-layer diffuser 101. An HEPA filter 3 is installed on the right side of the outer shell. The HEPA filter removes most impurities from the air while adjusting the airflow into the equipment via a variable frequency fan. The diffuser of the inner reactor is a corrosion- and oxidation-resistant diffuser made of nickel-containing material, with a pore size of less than or equal to 1.5 mm. 2 The number of layers is limited to 3-6 layers, and the diffuser mesh has a large hole 102 in the middle to facilitate the installation of the deposition torch 4. An overflow hole for clean air discharge is located on the left side of the outer casing. The opening and closing amplitude of the overflow hole is electrically controlled, and the pressure difference between the internal pressure of the outer reactor and the external air pressure is monitored to control the opening and closing amplitude. The air supply to the outer casing is controlled by a variable frequency fan, and the fan frequency is adjusted by monitoring the pressure difference between the inner and outer reactors.

[0013] This external vapor deposition dual-shell unit separates the deposition reactor from the main equipment design. This allows for the deposition of large-sized loose materials while avoiding the thermal deformation caused by simply increasing the number of blowtorches to increase flame heat. The dual-shell design requires only a small deposition reactor space; additional space can be added based on the product's size requirements. An outer shell is added around the inner reactor and circulated with clean air. This clean air surrounds the inner reactor, cooling it and, due to the significant pressure difference between the inside and outside, preventing the leakage of toxic and harmful substances generated within the inner reactor. It also reduces the entry of external impurities into the inner reactor, minimizing their impact on product quality, improving product quality, reducing losses due to impurities, and lowering production costs. Simultaneously, in conjunction with the exhaust system, the clean air suppresses toxic and harmful substances generated within the inner reactor, preventing leakage and ensuring a safer and more environmentally friendly production environment.

Claims

1. A dual-shell external vapor deposition apparatus for optical fiber preform fabrication, comprising an inner reactor (1) primarily used for deposition and an outer shell (2) surrounding the inner reactor, i.e., the outer reactor; characterized in that... The inner reactor (1) is provided with an exhaust end and an air inlet end on the left and right sides respectively. The exhaust end pipe on the left side is connected to an external waste gas treatment device, and the air inlet end on the right side is equipped with a multi-layer diffuser net (101). An air high efficiency filter (3) is installed on the right side of the outer shell. The air high efficiency filter filters out most of the impurities in the air, and the amount of air entering the equipment is adjusted by the control of the variable frequency fan.

2. The external vapor deposition dual-shell device for optical fiber preform fabrication according to claim 1, characterized in that... The diffuser mesh (101) of the inner reactor (1) is a corrosion-resistant and oxidation-resistant diffuser mesh made of nickel-containing material, and the pore size of the diffuser mesh is less than or equal to 1.5 mm. 2 The number of layers is limited to 3-6 layers, and the middle of the diffuser is provided with large holes (102) to facilitate the installation of deposition torches (4).

3. The external vapor deposition dual-shell device for optical fiber preform fabrication according to claim 1, characterized in that... The outer shell (2) is provided with an overflow hole on the left side to facilitate the discharge of clean air. The opening and closing amplitude of the overflow hole is controlled by electrical control and the opening and closing amplitude of the overflow hole is controlled by monitoring the pressure difference between the internal pressure of the outer reactor and the external air pressure.

4. The external vapor deposition dual-shell apparatus for optical fiber preform fabrication according to claim 1, characterized in that... The air intake of the outer shell (2) is controlled by a variable frequency fan, and the frequency of the fan is adjusted by monitoring the pressure difference between the inner and outer reactors.

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