WO2021189862A1

WO2021189862A1 - Vad blowtorch cleaning apparatus and cleaning method thereof

Info

Publication number: WO2021189862A1
Application number: PCT/CN2020/126184
Authority: WO
Inventors: 沈小平; 王兵钦; 何炳; 范忠阔; 谢晓寒; 戴杰; 陈斌
Original assignee: 通鼎互联信息股份有限公司
Priority date: 2020-03-27
Filing date: 2020-11-03
Publication date: 2021-09-30
Also published as: CN111468473A

Abstract

A VAD blowtorch cleaning apparatus, comprising a sweeping gas supply cabinet (21), a sweeping gas supply cabinet main pipe (22) and branch pipes, a monitoring computer (15), a PLC (16), a soft gas guide and exhaust pipe (77), automatic valves, float flow meters, and blowtorch group gas inlet pipes. By means of auxiliary devices such as the PLC (16) for controlling the automatic valves to open and close at intervals and the soft gas guide and exhaust pipe (77), a cleaning operation for the space of each layer inside a VAD blowtorch can be achieved in time and efficiently, and by means of flow control, the space of each layer inside the blowtorch can be accurately cleaned. In the process of cleaning the blowtorch, a combined deposition cavity gas suction pipe is purged by means of a high-pressure gas to form a large pressure difference between the inside and the outside of the blowtorch, so that powder impurities are synchronously suctioned out of the blowtorch and enter a waste gas recovery portion. The scaling rate at an inner layer of a quartz blowtorch is greatly reduced, the risks of bubble occurrence and optical parameter deterioration of an optical fiber preform core rod are reduced, the service life of the blowtorch is prolonged, and the production efficiency is greatly improved.

Description

A VAD blowtorch cleaning device and its cleaning method

This application claims the priority of the patent number 2020102283725 and the filing date of 20200327. The content of the priority document is added to this application file by reference.

Technical field

The invention belongs to the field of optical fiber preform manufacturing, and specifically relates to a VAD blowtorch cleaning device and a cleaning method thereof.

Background technique

In the existing optical fiber preform preparation process, the axial vapor deposition method (VAD) is often used to produce the core rod, and then the external vapor deposition method (OVD) is used to produce the two-step method for producing the optical fiber preform. The equipment for mandrel production by the VAD method is mainly composed of six parts: reaction chamber, blowtorch, raw gas supply part, loose body (SOOT body) lifting and rotating part, control computer and waste gas recovery part. Among them, the blowtorch group is one of the most critical components. The blowtorch group is usually composed of a core lamp and one or more package lamps. Its function is to spray out mixed gases such as _{Sicl 4} , Gecl ₄ , H ₂ , O _{2, etc.} In the burner area of the torch, a hydrolysis reaction occurs after high-temperature combustion to produce SiO ₂ , GeO ₂ and other powders (1), (2). SiO ₂ , GeO ₂ and other powders are deposited and attached to the surface of the rotating quartz target rod under the action of the thermophoretic principle to produce a VAD SOOT body.

Sicl ₄ +O ₂ +2H ₂ →SiO ₂ +4HCl (1)

GeCl ₄ +O ₂ +2H ₂ →GeO ₂ +4HCl (2)

The VAD SOOT body is then vitrified at a high temperature of 1500°C to finally produce a transparent optical fiber preform core rod. Compared with metal blowtorch, quartz blowtorch has been used in VAD process because of its good temperature resistance and no metal impurities.

The blowtorch is a place where the raw gas is mixed and reacted. The change of its internal structure directly affects the production cost and quality of the preform. During the production process, part of the SiO ₂ , GeO ₂ powder (powder impurity) not recovered by the waste gas recovery unit is easy The powder impurities fall into the torch after being adsorbed on the inner surface of the blowtorch or the SOOT body cracks. On the one hand, the accumulated powder impurities will cause the diameter of the blowtorch to become smaller, and in severe cases, the pores will be blocked. The smaller aperture of the blowtorch will directly affect the flow rate distribution of the raw material gas, resulting in a change in the optical refractive index profile of the preform, and deteriorating the quality of the preform. On the other hand, during the production process, the accumulated powder impurities will swim to the surface of the SOOT body. After the powder impurities of different densities are agglomerated, bubbles are prone to appear in the preform after high-temperature sintering, and air lines will appear when the bubbles are drawn into optical fibers. Phenomenon, it will also reduce the quality of the preform. Therefore, for the blowtorch, it is necessary to match efficient and regular cleaning operations. However, in the actual production process, the traditional blowtorch cleaning method has the following problems:

1. The traditional blowtorch cleaning method lacks high efficiency: blowtorch cleaning is usually carried out when the equipment is on standby. When there are a lot of powder impurities inside the blowtorch, it is first necessary to disassemble the raw gas pipeline connected to the surface of the blowtorch, and then use the high-pressure gas nitrogen (N2 ) Or compressed air (CDA) aiming at the nozzles of each layer of the torch to blow one by one. After the powder impurities in the torch are blown out of the lamp, after the purge work is completed, the raw gas pipelines are fixed to each of the torches through plastic adapters one by one on site. Layer nozzle surface. The entire process is basically all manual operation. The cleaning of the complex structure of the blowtorch requires higher operation requirements for the on-site personnel, especially the fixed connection operation of the plastic adapter and the quartz blowtorch. When manually twisting the internal thread of the plastic adapter, the force must be kept moderate , Excessive force is likely to cause damage to the torch interface, and too little force will easily cause poor airtightness of the raw material gas pipe and the torch connection, and gaseous raw materials may leak during the production process. Generally, as shown in Figure 5 and Figure 6, the VAD torch is composed of 4 to 10 layers of concentric tubes. For the lamp walls with different apertures in each layer of the torch, it is necessary to match the appropriate gas purge flow. In the traditional cleaning method of the torch, it is required Manually adjust the purge flow one by one several times, the overall workload is relatively large.

2. The traditional blowtorch cleaning method lacks timeliness: If the blowtorch cannot be cleaned in time in the early stage, after a long time of high temperature production, the powder impurities accumulated in the blowtorch will firmly adhere to the inner surface of the lamp wall. At this time, use high-pressure gas The effect of purging powder impurities is relatively poor, and it can only be cleaned with chemical reagents such as hydrofluoric acid after the blowtorch is disassembled. The entire process of disassembly, cleaning, installation and commissioning of the blowtorch is also relatively heavy, and the production efficiency is greatly reduced.

In summary, for VAD blowtorches, there is an urgent need for an efficient automatic cleaning device and cleaning method.

Summary of the invention

The technical problem to be solved by the present invention is: in order to solve the disadvantages of the prior art that the blowtorch cleaning method is low in automation and manual disassembly links are likely to cause damage to the blowtorch interface, and the blowtorch is not easy to clean in time, so as to provide a VAD blowtorch cleaning device And its cleaning method.

The technical solutions adopted by the present invention to solve its technical problems are:

A VAD blowtorch cleaning device, including:

Sweeping gas supply device, used to generate and discharge the gas used for cleaning the blowtorch;

The air inlet pipe switching mechanism has two air inlet ends and one air outlet, which is used to selectively switch to open one of the two air inlet ends and close the other pipe; one of the air inlet pipe switching mechanisms has an inlet The gas end is used to connect the raw material intake pipe;

One end of the blower group air inlet pipe is connected to the air outlet end of the air intake pipe switching mechanism, and the other end is connected to the blower group air inlet end;

The sweeping gas branch pipe has one end connected to the sweeping gas supply device, and the other end connected to the other intake end of the intake pipe switching mechanism;

The deposition chamber exhaust pipe is arranged at the exhaust end of the blowtorch group, and is used to suck powder impurities out of the blowtorch group.

Preferably, in the VAD blowtorch cleaning device of the present invention, the intake pipe switching mechanism includes:

A three-way pipe, the three-way pipe has two inlet ends and one outlet end;

An automatic valve is arranged at the raw material intake pipe and the cleaning gas branch pipe, and the automatic valve can control the opening and closing of the pipeline.

Preferably, in the VAD blowtorch cleaning device of the present invention, the deposition chamber exhaust pipe is welded to the side of the deposition chamber and faces the exhaust end of the blowtorch group, and the deposition chamber exhaust pipe passes through a soft guide The exhaust pipe is hermetically connected to the exhaust end of the burner group, and the soft exhaust pipe can be disassembled.

Preferably, in the VAD blowtorch cleaning device of the present invention, the blowtorch group is composed of a package lamp and a core lamp, and both the package lamp and the core lamp have a multi-layer structure, and each layer has an independent air inlet. End; the intake pipe switching mechanism, the blower group intake pipe, the cleaning gas branch pipe are corresponding to each layer of the package lamp and the core lamp.

Preferably, in the VAD blowtorch cleaning device of the present invention, the cleaning gas supply device is provided with a pressure regulating valve, a flow meter, an automatic valve and a pressure gauge respectively; each cleaning gas branch pipe is provided with a separate flow meter and automatic valve.

Preferably, the VAD torch cleaning device of the present invention further includes a programmable logic controller, and the cleaning gas supply device is connected to the programmable logic controller, and the programmable logic controller is used to control the opening and closing of all automatic valves. .

A cleaning method of a VAD blowtorch cleaning device includes the following steps:

S1, control the production of raw material gas supply cabinet to stop working;

S2, install the soft guide and exhaust pipe, connect one end of the soft guide and exhaust pipe to the exhaust end of the burner group, and the other end to the exhaust pipe of the deposition chamber;

S3, control the automatic valve on the raw material inlet pipe of the production raw gas supply cabinet to close, control the automatic valve on the purge gas supply device to open, and start the purge gas supply device to pass the purge gas to the burner group, and at the same time control the exhaust of the deposition chamber One end of the tube starts to pump air, sucking the powder impurities in the blowtorch group out of the blowtorch, and enters the exhaust gas recovery part.

Preferably, the cleaning method of the VAD torch cleaning device of the present invention is characterized in that: in step S3, a programmable logic controller is used to control the opening and closing of all automatic valves.

Preferably, the cleaning method of the VAD torch cleaning device of the present invention is characterized in that: in step S3, the programmable logic controller controls each automatic valve to open sequentially for a set period of time and then close.

Preferably, the cleaning method of the VAD torch cleaning device of the present invention is characterized in that: before step S3, the purge flow rate of each layer of the torch is set to be proportional to the volume of each layer of space inside the torch, and the flow rate is adjusted in step S3 To adjust the actual flow rate of each layer inside the torch.

The beneficial effects of the present invention are: directly switch the raw gas or clean gas at the inlet end of the torch, without disassembling the raw gas pipeline to clean the torch, reduce the number of pipe disassembly and assembly of the inlet pipe of the torch, and reduce the damage of the inlet pipe. Possibility; high degree of automation, eliminating the need for manual disassembly and assembly of the air inlet pipeline, cleaning can be carried out in time, greatly slowing down the fouling rate of the inner layer of the quartz blowtorch, and reducing the risk of bubbles in the optical fiber preform core rod and deterioration of optical parameters , Extend the service life of the torch and greatly improve the production efficiency.

By using the PLC controller to control the automatic valve opening and closing and the exhaust pipe and other auxiliary equipment, the internal space of the VAD torch can be cleaned in time and efficiently, and the internal space of the torch can be accurately cleaned through the flow control.

The technical solution of the present application will be further described below with reference to the drawings and embodiments.

Figure 1 is a schematic diagram of a VAD blowtorch cleaning device;

Figure 2 is a schematic diagram of a VAD blowtorch production device;

Figure 3 is a schematic diagram of the assembly of the VAD blowtorch production and cleaning device;

Fig. 4 is a schematic diagram of a device for controlling the flow direction of cleaning gas in the device of Fig. 1;

Figure 5 Schematic diagram of traditional VAD five-layer package lamp;

Figure 6 Schematic diagram of a traditional VAD five-layer core lamp;

Figure 7 A cross-sectional view of a traditional VAD five-layer lamp;

Figure 8 is a cross-sectional view of a traditional VAD five-layer core lamp;

Figure 9 Soft guide exhaust pipe;

Fig. 10 is a comparison diagram of the refractive index profile of the optical fiber preform core rod prepared by the cleaning method of the VAD torch and the conventional cleaning method of the present invention.

Description of drawing symbols:

Deposition chamber 1, VAD package lamp 2, VAD core lamp 3, deposition chamber exhaust pipe 4, monitoring computer 15, PLC controller 16, first automatic valve 25, second automatic valve 26, third automatic valve 28, The fourth automatic valve 33, the fifth automatic valve 38, the sixth automatic valve 43, the seventh automatic valve 48, the eighth automatic valve 53, the ninth automatic valve 58, the tenth automatic valve 63, the eleventh automatic valve 68, the Twelve automatic valve 73, thirteenth automatic valve 17, fourteenth automatic valve 18, production material gas supply cabinet one 19, production material gas supply cabinet two 20, cleaning gas supply cabinet 21, cleaning gas supply cabinet supervisor 22, cleaning Gas supply cabinet main pressure regulating valve 23, pressure gauge 81, first float flow meter 24, second float flow meter 29, third float flow meter 34, fourth float flow meter 39, fifth float flow meter 44, sixth float flow meter Float flow meter 49, seventh float flow meter 54, eighth float flow meter 59, ninth float flow meter 64, tenth float flow meter 69, eleventh float flow meter 74, cleaning gas first branch pipe 37, cleaning gas The second branch pipe 42, the third branch pipe of sweeping gas 32, the fourth branch pipe of sweeping gas 47, the fifth branch pipe of sweeping gas 27, the sixth branch pipe of sweeping gas 62, the seventh branch pipe of sweeping gas 67, the eighth branch pipe of sweeping gas 57, the fourth branch pipe of sweeping gas. Nine branch pipes 72, cleaning gas tenth branch pipe 52, raw material gas production first inlet pipe 41, raw material gas production second inlet pipe 46, raw material gas production third inlet pipe 36, raw material gas production fourth inlet pipe 51, raw material gas production Fifth gas inlet pipe 31, sixth gas inlet pipe 66 for raw material gas production, seventh gas inlet pipe 71 for raw material gas production, eighth gas inlet pipe 61 for raw material gas production, ninth gas inlet pipe 76 for raw material gas production, and tenth gas inlet pipe 56 for raw material gas production , Baodeng first layer of air inlet pipe port 5, Baodeng second layer of air inlet pipe port 6, Baodeng third layer of air inlet pipe port 7, Baodeng fourth layer of air inlet pipe port 8, Baodeng fifth layer of air inlet pipe port 9 , The first layer of core lamp intake pipe port 10, the second layer of core lamp intake pipe port 11, the third layer of core lamp intake pipe port 12, the fourth layer of core lamp intake pipe port 13, the fifth layer of core lamp intake pipe port 14 , Baodeng first layer air intake pipe 40, Baodeng second layer air intake pipe 45, Baodeng third layer air intake pipe 35, Baodeng fourth layer air intake pipe 50, Baodeng fifth layer air intake pipe 30, core lamp first Layer intake pipe 65, core lamp second layer intake pipe 70, core lamp third layer intake pipe 60, core lamp fourth layer intake pipe 75, core lamp fifth layer intake pipe 55, soft guide exhaust pipe 77, soft The opening of the flexible guide and exhaust pipe is 78, the opening of the soft guide and exhaust pipe is 79, the opening of the flexible guide and exhaust pipe is 80, the inner diameter of the first layer of the lamp is D1, the inner diameter of the second layer of the lamp is D2, the inner diameter of the third layer of the lamp D3, the inner diameter of the fourth layer of the lamp D4, the inner diameter of the fifth layer of the lamp D5, the inner diameter of the first layer of the core lamp D6, the inner diameter of the second layer of the core lamp D7, the inner diameter of the third layer of the core lamp is D8, the inner diameter of the fourth layer of the core lamp is D9, the inner diameter of the fifth layer of the core lamp is D10, the distance between the bottom of the first layer of the lamp and the bottom of the tube is L1, the second is the second The distance between the bottom of the connected tube of the layer is L2, the distance of the bottom of the third layer of the lamp is L3, the distance of the bottom of the fourth layer of the lamp is L4, the distance of the bottom of the fifth layer of the lamp is L5, the distance between the bottom of the first layer of the core lamp is L6 , The distance between the bottom of the connected tube of the second layer of the core lamp is L7, the distance of the bottom of the connected tube of the third layer of the core lamp is L8, the bottom distance of the connected tube of the fourth layer of the core lamp is L9, and the bottom distance of the fifth layer of the core lamp is L10.

Detailed ways

It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other if there is no conflict.

In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention will be further explained below in conjunction with specific implementations.

This embodiment provides a VAD blowtorch cleaning device, including:

The cleaning gas supply device (specifically, the cleaning gas supply cabinet 21) is used to generate and discharge the gas used for cleaning the blowtorch;

The intake pipe switching mechanism (specifically, the three-way pipe and the first to fourteen automatic valves), has two intake ends, one exhaust end, which is used to switch open and close one of the two intake ends. Another pipeline; one of the inlet ends of the inlet pipeline switching mechanism is used to connect the raw material inlet pipe;

The air inlet pipe of the blowtorch group (specifically includes the first, second, third, fourth, and fifth-layer air inlet pipes of the package lamp and the first, second, third, fourth, and fifth-layer air inlet pipes of the core lamp), one end is connected with the air inlet pipe switching mechanism The other end is connected to the air inlet end of the blowtorch group;

Sweep gas branch pipes (specifically include sweep gas first, second, third, fourth, five, six, seven, eight, nine, ten branch pipes), one end is connected to the sweeping gas supply device, and the other end is connected to the inlet pipe switching mechanism The other intake end;

The deposition chamber exhaust pipe 4 is arranged at the exhaust end of the blowtorch group, and is used to suck powder impurities out of the blowtorch group.

Preferably, in the VAD torch cleaning device of this embodiment, the intake pipe switching mechanism includes:

A three-way pipe, the three-way pipe has two inlet ends and one outlet end;

Preferably, in the VAD blowtorch cleaning device of this embodiment, the deposition chamber exhaust pipe is welded to the side of the deposition chamber and faces the exhaust end of the blowtorch group, and the deposition chamber exhaust pipe passes through a soft The exhaust air duct is sealed to the exhaust end of the burner group, and the soft exhaust air duct can be disassembled.

Preferably, in the VAD blowtorch cleaning device of this embodiment, the blowtorch group is composed of a package lamp and a core lamp, and both the package lamp and the core lamp have a multi-layer structure, and each layer has an independent inlet. The gas end; the intake pipe switching mechanism, the blower group intake pipe, and the cleaning gas branch pipe are set corresponding to each layer of the package lamp and the core lamp.

Preferably, in the VAD blowtorch cleaning device of this embodiment, the cleaning gas supply device is provided with a pressure regulating valve, a flow meter, an automatic valve and a pressure gauge respectively; each cleaning gas branch pipe is provided with a separate flow meter and automatic valve .

Preferably, the VAD torch cleaning device of this embodiment further includes a programmable logic controller, and the cleaning gas supply device is connected to the programmable logic controller, and the programmable logic controller is used to control the opening of all automatic valves. close.

This embodiment provides a method for cleaning a VAD torch cleaning device. Using the above-mentioned VAD torch cleaning device includes the following steps:

S1, control the production of raw material gas supply cabinet to stop working;

Preferably, the cleaning method of the VAD torch cleaning device of this embodiment is characterized in that: in step S3, a programmable logic controller is used to control the opening and closing of all automatic valves.

Preferably, the cleaning method of the VAD torch cleaning device of this embodiment is characterized in that: in step S3, the programmable logic controller controls each automatic valve to open sequentially for a set period of time and then close.

Preferably, the cleaning method of the VAD torch cleaning device of this embodiment is characterized in that: before step S3, the purge flow rate of each layer of space inside the torch is set to be proportional to the volume of each layer of space inside the torch, and in step S3, through adjustment Flow meter to adjust the actual flow rate of each layer inside the torch.

As shown in Figure 1, a VAD blowtorch cleaning device includes a cleaning gas supply cabinet 21, a cleaning gas supply cabinet main 22, a monitoring computer 15, a lamp 2, a core lamp 3, an air inlet pipe 40 on the first layer of the lamp, and a lamp The second layer air intake pipe 45, the third layer air intake pipe 35 of the package lamp, the fourth layer air intake pipe 50 of the package light, the fifth layer air intake pipe 30 of the package light, the first layer air intake pipe 65 of the core lamp, the second layer air intake pipe of the core lamp 70. The third layer of core lamp intake pipe 60, the fourth layer of core lamp intake pipe 75, the fifth layer of core lamp intake pipe 55, the deposition chamber 1, the deposition chamber exhaust pipe 4, the soft guide exhaust pipe 77, And the first branch pipe 37, the second branch pipe 42, the third branch pipe 32, the fourth branch pipe 47, the fifth branch pipe 27 and the core lamp 3 are respectively passed into the cleaning gas supply cabinet main pipe 22 to the package lamp 2 The sixth branch pipe 62, the seventh branch pipe 67, the eighth branch pipe 57, the ninth branch pipe 72, and the tenth branch pipe 52 of the main pipe 22 of the gas supply cabinet are cleaned.

As shown in FIG. 3, the main pipe 22 of the cleaning gas supply cabinet is provided with a pressure regulating valve 23, a first float flow meter 24, a first automatic valve 25, a second automatic valve 26 and a pressure gauge 81 respectively. The first branch pipe 37 of the main pipe 22 of the cleaning gas supply cabinet is provided with a fifth automatic valve 38 and a fourth float flowmeter 39, respectively, and the second branch pipe 42 is provided with a sixth automatic valve 43, a fifth float flowmeter 44, and a third branch respectively. 32 is provided with a fourth automatic valve 33 and a third float flowmeter 34, the fourth branch pipe 47 is provided with a seventh automatic valve 48 and a sixth float flowmeter 49, respectively, and the fifth branch pipe 27 is provided with a third automatic valve 28 and The second float flowmeter 29 and the sixth branch pipe 62 are respectively provided with a tenth automatic valve 63 and a ninth float flowmeter 64, and the seventh branch pipe 67 is respectively provided with an eleventh automatic valve 68 and a tenth float flowmeter 69, eighth The branch pipe 57 is provided with a nine automatic valve 58 and an eighth float flow meter 59 respectively, a ninth branch pipe 72 is provided with a twelfth automatic valve 73 and an eleventh float flow meter 74, and the tenth branch pipe 52 is provided with an eighth automatic valve respectively. 53 and the seventh float flow meter 54.

In one of the embodiments, the VAD torch is composed of a package lamp 2 and a core lamp 3. As shown in Figures 5 and 7, the package lamp 2 has a five-layer structure, marked from the inside to the outside as the first layer and the first The second layer, third layer, fourth layer, and fifth layer, as shown in Figure 6 and Figure 8, the core lamp 3 has a five-layer structure, marked from the inside to the outside as the first layer, the second layer, the third layer, and the first layer. The fourth and fifth floors. As shown in Figure 3, the two ends of the first layer of air inlet pipe 40 of the lamp are respectively connected with the first branch pipe 37 of cleaning gas and the first layer of air intake pipe port 5, and the two ends of the air inlet pipe of the second layer of lamp are respectively connected with the first cleaning gas. Both ends of the two branch pipes 42 and the air intake pipe port 6 of the second layer of the lamp and the air intake pipe 35 of the third layer of the lamp are respectively connected with the third branch pipe 32 of the cleaning gas and the third layer of the lamp 7 and the fourth layer of the lamp. Both ends of 50 are respectively connected with the fourth branch pipe 47 of sweeping gas and the inlet port 8 of the fourth layer of the lamp, and the fifth layer intake pipe 30 of the lamp is respectively connected with the fifth branch pipe 27 of the sweeping gas and the fifth layer inlet port 9 of the lamp. The two ends of the first-layer intake pipe 65 of the core lamp are respectively connected with the sixth branch pipe 62 of the cleaning gas and the first layer intake pipe port 10 of the core lamp, and the two ends of the second-layer intake pipe 70 of the core lamp are respectively connected with the seventh branch pipe 67 of the cleaning gas and the core. The two ends of the lamp second layer intake pipe port 11 and the core lamp third layer intake pipe 60 are respectively connected to the sweep gas eighth branch pipe 57, the core lamp third layer intake pipe port 12, and the core lamp fourth layer intake pipe 75 are respectively connected to both ends Both ends of the ninth branch pipe 72 for cleaning gas, the inlet pipe port 13 of the fourth layer of the core lamp, and the inlet pipe 55 of the fifth layer of the core lamp are respectively connected with the tenth branch pipe 52 of the cleaning gas and the fifth layer inlet pipe port 14 of the core lamp.

In one of the embodiments, it also includes a PLC controller 16, a production raw gas supply cabinet 19, a production raw gas supply cabinet 20, and a purge gas supply cabinet 21 are connected to the PLC controller 16, and the PLC controller 16 is used to control all Automatic valve opening and closing.

As shown in Figure 9, before the blowtorch is cleaned, the soft guide and exhaust pipe 77 is manually installed. The soft guide and exhaust pipe is provided with opening 78, opening 79, and opening 89. Hole two 79 and opening three 89 are respectively seamlessly wrapped with the lamp socket of the lamp 2 lamp socket, the lamp socket of the core lamp 3, and the nozzle socket 4 of the deposition chamber exhaust pipe, and the air tightness is good. During the cleaning process of the torch, the suction force of the suction pipe 4 of the combined deposition chamber with high pressure gas is used to form a large pressure difference between the inside and outside of the torch to suck the powder impurities out of the torch and enter the exhaust gas recovery part. Then, the PLC controller 16 is triggered by the monitoring computer 15, and the cleaning gas supply cabinet 21 starts to work. By adjusting the flow of the float flowmeter and the PLC controller 16 to control all automatic valves to open and close, the cleaning gas of different flows can be cleaned one by one. The function of each layer of space inside the lamp.

In one of the embodiments, the exhaust pipe 4 of the deposition chamber is welded to the side of the deposition chamber 1 to face the package lamp 2 and the core lamp 3. When the equipment is in standby and in production, the exhaust in the exhaust duct 4 of the deposition chamber is kept normally open.

In one of the embodiments, it also includes production material gas supply cabinet 1 19 and production material gas supply cabinet 2 20. During the torch production process, production material gas supply cabinet 1 19 and production material gas supply cabinet 2 20 work normally, and the production is working. After the end, the blowtorch enters the cleaning process. The production raw gas supply cabinet 20 is provided with a first inlet pipe 41, a second inlet pipe 46, a third inlet pipe 36, a fourth inlet pipe 51, and a fifth inlet pipe 31 for production raw gas, and a first inlet pipe 41 for production raw gas , The second air inlet pipe 46, the third air inlet pipe 51, the fourth air inlet pipe 46, and the fifth air inlet pipe 31 respectively communicate with the first-layer air-intake pipe 40, the second-layer air-intake pipe 45, the third-layer air-intake pipe 35, and the second air-intake pipe. The fourth-layer intake pipe 50, the fifth-layer intake pipe 30, the production raw gas supply cabinet two 20 are provided with the sixth intake pipe 66, the seventh intake pipe 71, the eighth intake pipe 61, the ninth intake pipe 76, and the second raw gas supply cabinet 20. Ten air inlet pipe 56, which produces raw material gas. The sixth air inlet pipe 66, the seventh air inlet pipe 71, the eighth air inlet pipe 61, the ninth air inlet pipe 76, and the tenth air inlet pipe 56 respectively communicate with the core lamp first layer air inlet pipe 65 and the second air inlet pipe. Layer intake pipe 70, third layer intake pipe 60, fourth layer intake pipe 75, fifth layer intake pipe 55.

In one of the embodiments, the material of the VAD package lamp and the VAD core lamp is GE-214 quartz.

In one of the embodiments, the soft guide and exhaust pipe 77 is made of PVC steel wire telescopic hose, which has good elasticity, is easy to install, and is detachable.

In one of the embodiments, the main pipe 22 of the cleaning gas supply cabinet and all the cleaning gas branch pipes are made of 316 stainless steel, and all the blowtorch air inlet pipes and all the production raw gas inlet pipes are made of Teflon. The main pipe of the cleaning gas supply cabinet has a diameter of 1/2 inch, the diameter of all cleaning gas branch pipes is 1/4 inch, and the diameter of all blowtorch air inlet pipes is 3/8 inch.

The invention also discloses a cleaning method of a VAD blowtorch cleaning device, the method includes the following steps:

(a) Blowtorch cleaning preparation 1: After the VAD deposition is completed, the thirteenth automatic valve 17 and the fourteenth automatic valve 20 are automatically closed, and the operator removes the SOOT body from the deposition chamber 1, and then installs a soft guide exhaust Tube 77, seamlessly wrap the elastic opening 78, opening 2 79, and opening 3 89 with the lamp socket of the lamp 2, the lamp socket of the core lamp 3, and the nozzle of the deposition chamber exhaust pipe 4 respectively;

(b) Blowtorch cleaning preparation 2: Open the N2 supply tank main pressure regulator valve 23, adjust the pressure regulator, the N2 supply tank pressure 0.3Mpa, adjust the first float flowmeter 24, control the N2 supply tank main flow F1: 100 ~ 150SLM , The PLC controller 16 is triggered by the monitoring computer 15 to open the first automatic valve 25 and the second automatic valve 26 synchronously in sequence;

(c) N2 flow adjustment: As shown in Figure 7, Figure 8 and Table 1, the volume of each layer inside the torch is different. In theory, different layers need to match different purge flows.

As shown in Table 2, the setting value of the purge flow of each layer of space inside the torch is proportional to the volume of each layer of space inside the torch;

(d) The PLC controller 16 works: the PLC controller 16 is triggered by the monitoring computer 15. As shown in Table 3, the PLC controller 16 responds at time T1:1～5s (seconds), T2:10～15s, T3 : 15～25s, T4: 20～35s, T5: 25～45s, T6: 30～55s, T7: 35～65s, T8: 40～75s, T9: 45～85s, T10: 60～100s, T11:100 After ~120s, the automatic valve is opened and closed synchronously. As shown in Figure 4, the flow direction of N2 from the supply cabinet into the blowtorch air pipe. The cleaning process of each layer inside the blowtorch is in accordance with step ①-

Proceed in sequence

Note: In the table, the automatic valve mark 0 refers to open, and the automatic valve mark 1 refers to closed.

(e) Close the first automatic valve 25 and the second automatic valve 26 synchronously in sequence, disassemble the soft guide and exhaust pipe 77, and seal the blowtorch lamp port with a plastic lampshade to prevent powder impurities from falling inside the blowtorch, and the entire blowtorch is clean End of work;

(f) The torch is normally used for the deposition of the SOOT body to prepare the core rod of the optical fiber preform;

(g) In the later production process, when the space inside each layer of the VAD burner reaches the cleaning standard, the flow rate of the float flowmeter on the cleaning gas main and branch pipes remains unchanged.

The invention also provides several specific implementation scenarios.

Specific implementation scenario 1:

(a) After the completion of VAD deposition, the thirteenth automatic valve and the fourteenth automatic valve are automatically closed. The operator removes the SOOT body from the deposition chamber, and then installs a soft exhaust pipe to open the elastic opening. Hole two and opening three are seamlessly wrapped with the lamp socket of the lamp, the lamp socket of the core lamp, and the nozzle of the exhaust pipe of the deposition chamber respectively;

(b) Open the N2 supply tank main pressure regulating valve, manually adjust the first float flowmeter, control the N2 supply tank main flow F1: 120SLM, and trigger the PLC controller to open the first automatic valve and the second automatic valve synchronously in sequence through the monitoring computer;

(c) As shown in Table 4 and Table 5, it is the N2 cleaning flow rate, cleaning time and cleaning sequence of each layer of the torch inside the torch;

(d) Close the first automatic valve and the second automatic valve synchronously in sequence, disassemble the soft guide and exhaust pipe, seal the blowtorch lamp port with a plastic lampshade, and the entire blowtorch cleaning work is over;

(e) The torch is normally used for the deposition of the SOOT body to prepare the core rod of the optical fiber preform.

Compared with the traditional cleaning method, the core lamp starts to show a slight scaling phenomenon after 2 months of use, and the scaling is more serious after 3 to 4 months of use. Hydrofluoric acid is required to pickle the scaled parts after 5 months of use. After the VAD blowtorch is cleaned by the device and cleaning method of the present invention, the rate of fouling in the inner layer of the lamp and the core lamp is greatly reduced. The core lamp has a slight structural phenomenon after 6 months of use. The fouling is more serious after 10 to 11 months of use. At 12 months, hydrofluoric acid is required to pickle the fouled parts.

Specific implementation scenario 2:

(a) After the completion of VAD deposition, the thirteenth automatic valve and the fourteenth automatic valve are automatically closed. The operator removes the SOOT body from the deposition chamber, and then installs a soft exhaust pipe to open the elastic opening. Hole two and opening three are seamlessly wrapped with the lamp socket of the package lamp, the lamp socket of the core lamp, and the nozzle of the exhaust pipe of the deposition chamber;

(b) Open the N2 supply cabinet main pressure regulating valve, manually adjust the first float flowmeter, control the N2 supply cabinet main flow F1:100SLM, and trigger the PLC controller to open the first automatic valve and the second automatic valve synchronously in sequence through the monitoring computer;

(c) As shown in Table 6 and Table 7, it is the N2 cleaning flow rate, cleaning time and cleaning sequence of each layer of the torch inside each layer of the torch;

(d) Close the first automatic valve and the second automatic valve synchronously in sequence, disassemble the soft guide and exhaust pipe, seal the blowtorch lamp port with a plastic lampshade, and complete the cleaning of the blowtorch;

VAD blowtorch prepared by the traditional cleaning method, the fiber preform core rod cladding began to appear more bubbles in about 2 to 3 months, the number of bubbles was 2 to 5, and the core layer began to appear more bubbles in about 3 to 4 months. The number of bubbles is 3～5. Compared with the traditional cleaning method, the fiber preform mandrel produced by the VAD blowtorch cleaned by the device and cleaning method of the present invention has more air bubbles, and the phenomenon of more air bubbles starting to appear in the core rod cladding about 8 to 10 months. The number is 2 to 4. The core layer starts to appear more bubbles in about 10 to 12 months, and the number of bubbles is 1 to 4.

Specific implementation scenario 3:

(b) Open the N2 supply cabinet main pressure regulating valve, manually adjust the first float flowmeter, control the N2 supply cabinet main flow F1: 150SLM, and trigger the PLC controller to open the first automatic valve and the second automatic valve synchronously in sequence through the monitoring computer;

(c) As shown in Table 8 and Table 9, it is the N2 cleaning flow rate, cleaning time and cleaning sequence of each layer of the torch inside the torch;

Figure 10 shows the comparison of the refractive index profile of the optical fiber preform mandrel produced by the embodiment of the present invention and the traditional cleaning method to clean the blowtorch. Under the embodiment of the present invention, the comparison of the optical parameters of the mandrel after 4 months and 8 months of continuous production of VAD Ideal and meet the design requirements of single-mode fiber. For example, the refractive index profile is significantly better than the refractive index profile of the core rod after 4 months of continuous production of VAD under the cleaning of the traditional method.

Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have Various changes and improvements fall within the scope of the claimed invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

A VAD blowtorch cleaning device, which is characterized in that it comprises:

Sweeping gas supply device, used to generate and discharge the gas used for cleaning the blowtorch;

The air inlet pipe switching mechanism has two air inlet ends and one air outlet, which is used to selectively switch to open one of the two air inlet ends and close the other pipe; one of the air inlet pipe switching mechanisms has an inlet The gas end is used to connect the raw material intake pipe;

One end of the blower group air inlet pipe is connected to the air outlet end of the air intake pipe switching mechanism, and the other end is connected to the blower group air inlet end;

The sweeping gas branch pipe has one end connected to the sweeping gas supply device, and the other end connected to the other intake end of the intake pipe switching mechanism;

The deposition chamber exhaust pipe is arranged at the exhaust end of the blowtorch group, and is used to suck powder impurities out of the blowtorch group.
The VAD torch cleaning device according to claim 1, wherein the intake pipe switching mechanism comprises:

A three-way pipe, the three-way pipe has two inlet ends and one outlet end;

An automatic valve is arranged at the raw material intake pipe and the cleaning gas branch pipe, and the automatic valve can control the opening and closing of the pipeline.
The VAD blowtorch cleaning device according to claim 2, wherein the deposition chamber exhaust pipe is welded to the side of the deposition chamber and faces the exhaust end of the blowtorch group, and the deposition chamber is exhausted. The pipe is connected to the exhaust end of the burner group in a sealed manner through a soft guide and exhaust pipe, and the soft guide and exhaust pipe can be disassembled.
The VAD blowtorch cleaning device according to any one of claims 1 to 3, wherein the blowtorch group is composed of a package lamp and a core lamp, and the package lamp and the core lamp are both multilayered In the structure, each layer has an independent air inlet end; the air inlet pipe switching mechanism, the blower group air inlet pipe, and the cleaning gas branch pipe are arranged corresponding to each layer of the package lamp and the core lamp.
The VAD blowtorch cleaning device according to claim 4, wherein the cleaning gas supply device is respectively provided with a pressure regulating valve, a flow meter, an automatic valve and a pressure gauge; each cleaning gas branch pipe is provided with a separate flow rate Meter and automatic valve.
The VAD torch cleaning device according to claim 5, further comprising a programmable logic controller, the cleaning gas supply device is connected to the programmable logic controller, and the programmable logic controller is used to control all Automatic valve opening and closing.
A method for cleaning a VAD blowtorch cleaning device, which is characterized in that it comprises the following steps:

S1, control the production of raw material gas supply cabinet to stop working;

S2, install the soft guide and exhaust pipe, connect one end of the soft guide and exhaust pipe to the exhaust end of the burner group, and the other end to the exhaust pipe of the deposition chamber;

S3, control the automatic valve on the raw material inlet pipe of the production raw gas supply cabinet to close, control the automatic valve on the purge gas supply device to open, and start the purge gas supply device to pass the purge gas to the burner group, and at the same time control the exhaust of the deposition chamber One end of the tube starts to pump air, sucking the powder impurities in the blowtorch group out of the blowtorch, and enters the exhaust gas recovery part.
8. The cleaning method of the VAD torch cleaning device according to claim 7, characterized in that: in step S3, a programmable logic controller is used to control the opening and closing of all automatic valves.
The cleaning method of the VAD torch cleaning device according to claim 8, characterized in that: in step S3, the programmable logic controller controls each automatic valve to open sequentially for a set period of time and then close.
The cleaning method of the VAD torch cleaning device according to claim 9, characterized in that: before step S3, the purge flow rate of each layer of space inside the torch is set to be proportional to the volume of each layer of space inside the torch, and in step S3, it is adjusted Flow meter to adjust the actual flow rate of each layer inside the torch.