A collection device and collection method for carbon nanotube fibers

Abstract

The present invention discloses a collection device and method for carbon nanotube fibers, relating to the technical field of carbon nanotube fiber preparation. The device comprises a mesh belt transfer assembly, wherein a fiber outlet pipe and an exhaust pipe are symmetrically connected on both sides of the mesh belt transfer assembly. The fiber outlet pipe brings the carbon nanotube fibers to the mesh belt transfer assembly under the flow of carrier gas and the airflow of the exhaust pipe. A brush stripping assembly is provided on one side of the mesh belt transfer assembly for stripping and transferring the carbon nanotube fibers on the mesh belt transfer assembly. A magnetic roller adsorption assembly is installed below the brush stripping assembly to intermittently adsorb and transfer the carbon nanotube fibers above to a product collection assembly provided below the brush stripping assembly. The present invention utilizes the physical properties of carbon nanotube fibers to achieve a dry continuous collection process for the carbon nanotube fibers, thereby avoiding the problem of drying the carbon nanotube fibers after wet collection, reducing energy consumption, greatly reducing costs, and being suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon nanotube fiber preparation, in particular to a device and method for collecting carbon nanotube fibers. Background Art

[0002] As a new type of one-dimensional nanomaterial, carbon nanotubes (CNTs) are widely used in new energy, transparent displays, anti-static, semiconductors, engineering plastics, and other fields due to their excellent electrical and thermal conductivity, temperature resistance, chemical resistance, and mechanical properties. Currently, conventional methods for preparing single-walled or oligo-walled CNTs, such as the floating catalytic method and the arc method, often produce CNTs in the form of fibers with large surface areas, prone to forming a spiderweb-like macroscopic structure, and high outlet temperatures. This makes continuous collection of CNT fibers in large quantities challenging.

[0003] Traditional carbon nanotube fiber collection methods mainly include two categories, namely negative pressure collection and normal pressure collection. Among them, negative pressure collection uses cyclone dust removal equipment connected to the carbon nanotube fiber outlet to collect the product into the collection cavity through negative pressure. This method has a high collection efficiency, but there are some disadvantages, such as the high sealing performance requirements of the entire preparation system. Once air infiltrates the reaction cavity, explosions and other safety accidents are prone to occur. Normal pressure collection uses inert gas to blow the carbon nanotube fibers to a low-temperature area under normal pressure conditions, and then uses a collection device to collect them.

[0004] Atmospheric pressure collection can be divided into dry collection and wet collection. Dry collection involves placing a winding device at the outlet for collection. Patent publication numbers CN216711044U and CN108609434A are two patents. The synthesized carbon nanotube fibers are collected on the surface of a winding roller. However, continuous collection is not possible and the product needs to be cleaned regularly. Moreover, because the collection roller is much larger than the discharge pipe, an oversized roller is required for collection, which is not conducive to large-scale production. Wet collection involves collecting carbon nanotube fibers in water using spraying or bubbling. Continuous collection can be achieved by setting up a collection water tank. However, the carbon nanotube fibers collected using this method need to be dried before use. Due to the high specific surface area of ​​carbon nanotube fibers, removing moisture from the fibers requires a lot of energy, especially removing trace moisture. Therefore, this method also has certain limitations. To this end, we provide a collection device and collection method for carbon nanotube fibers to facilitate the subsequent application of carbon nanotubes. Summary of the Invention

[0005] The object of the present invention is to provide a device and method for collecting carbon nanotube fibers to solve the problems in the above-mentioned background technology.

[0006] The present invention can be implemented through the following technical solution: a carbon nanotube fiber collection device includes a mesh belt transfer assembly, wherein a fiber outlet pipe and an exhaust pipe are sealed and connected to each other at symmetrical positions on both sides of the mesh belt transfer assembly, and the fiber outlet pipe carries the carbon nanotube fibers to the mesh belt transfer assembly under the flow of carrier gas and the airflow of the exhaust pipe;

[0007] A brush stripping assembly is provided on one side of the mesh belt transfer assembly to strip and transfer the carbon nanotube fibers on the mesh belt transfer assembly. A magnetic roller adsorption assembly is installed below the brush stripping assembly to perform intermittent adsorption and transfer of the carbon nanotube fibers above to the product collection assembly provided below it.

[0008] A further technical improvement of the present invention is that the mesh belt transfer assembly includes a sealing cover, the fiber outlet pipe and the exhaust pipe are sealed and connected to the sealing cover, a pair of rotating guide rollers are rotatably installed in the sealing cover, and the two rotating guide rollers jointly drive a closed-drive mesh belt, and the carbon nanotube fibers are transferred when they contact the mesh belt.

[0009] A further technical improvement of the present invention is that the brush stripping assembly includes a brush roller rotatably arranged in a sealing cover, and brush filaments are arranged on the periphery of the brush roller. The brush filaments are in contact with the outer side of the mesh belt and the instantaneous tangential velocities of the two at the contact part are in opposite directions.

[0010] A further technical improvement of the present invention is that the magnetic roller adsorption assembly includes a hollow roller rotatably installed in a sealing cover, a fan-shaped electromagnet is provided in the hollow roller, the on and off time of the electromagnet is coordinated with the rotational speed of the hollow roller, and wind knives are symmetrically provided on both sides of the hollow roller, and the extension direction of the air outlet of each wind knife is tangent to the outer side of the hollow roller.

[0011] A further technical improvement of the present invention is that the product collection assembly includes a product collection box and a sealing partition, the product collection box is connected to the sealing cover, and the sealing partition is slidably arranged between the product collection box and the sealing cover to control the opening and closing state of the communication channel between the two.

[0012] A further technical improvement of the present invention is that the mesh belt structure includes a porous structure formed by rolling metal fiber wire or a porous hollow structure formed by opening holes on the surface of a metal foil.

[0013] A further technical improvement of the present invention is that the hollow roller is made of polyurethane rubber, the length of the hollow roller is the same as the width of the mesh belt, and the width of the mesh belt exceeds the opening of the fiber outlet pipe by more than 50 mm.

[0014] A further technical improvement of the present invention is that a cooling air pipe is provided between a pair of rotating guide rollers, and a plurality of cooling air nozzles are evenly connected and installed on the outer circumference of the cooling air pipe. The cooling air nozzles are arranged toward the air outlet direction of the fiber outlet pipe and blow out liquid nitrogen to cool the mesh belt on that side.

[0015] A collection method of a carbon nanotube fiber collection device, characterized by comprising the following steps:

[0016] Step 1: Connect the components according to the device and ensure sealing, open the exhaust pipe to make the entire device a negative pressure state, and open the connection channel between the product collection component and the mesh belt transfer component;

[0017] Step 2: Open the fiber outlet pipe to allow the carbon nanotube fibers to enter the collection device under the drive of the carrier gas. Simultaneously, start the mesh belt transfer component, brush stripping component, and magnetic roller adsorption component, and introduce liquid nitrogen into the device.

[0018] Step 3: Observe the accumulation of products in the product collection component. When the product accumulates to a certain amount, close the connection channel between the product collection component and the mesh belt transfer component, and empty and collect the carbon nanotube fibers in the product collection component. After the collection is completed, open the channels of the two components while ensuring that the product collection component and the mesh belt transfer component are tightly connected.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. Under normal pressure conditions, the present invention transfers carbon nanotube fibers to a low-temperature zone far away from the fiber outlet pipe through a continuously conveying mesh belt, and brushes the carbon nanotube fibers on the mesh belt with the brush wire on the brush stripping component, and utilizes the ferromagnetic properties of the carbon nanotube fibers to make them be adsorbed by the magnetic roller adsorption component. Subsequently, a wind knife is used to easily peel the product from the hollow roller and put it into the product collection component; the physical properties of the carbon nanotube fibers are utilized to realize the process of dry continuous collection of the carbon nanotube fibers, which can avoid the problem of drying the carbon nanotube fibers after wet collection, reduce energy consumption, greatly reduce costs, and is suitable for large-scale industrial production.

[0021] 2. The present invention uses an electromagnet inside the hollow roller to control the power on and off, and cooperates with an air knife to overcome the problem that carbon nanotube fibers are easily adhered to the surface of objects due to their ultra-high specific surface area, greatly reducing the difficulty of collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0023] Figure 1 Schematic diagram of the internal structure of the overall device of the present invention;

[0024] Figure 2 For the present invention Figure 1 A magnified diagram of the details in the middle;

[0025] Figure 3 It is a schematic diagram of the structural connection of the present invention.

[0026] In the figure: 1. Fiber outlet pipe; 2. Mesh belt transfer assembly; 3. Brush stripping assembly; 4. Magnetic roller adsorption assembly; 5. Product collection assembly; 6. Exhaust duct; 201. Sealing cover; 202. Rotating guide roller; 203. Mesh belt; 204. Cooling air nozzle; 301. Brush roller; 302. Brush wire; 401. Hollow roller; 402. Electromagnet; 403. Air knife; 501. Product collection box; 502. Sealing partition; 503. Glass observation window. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0028] See also Figure 1-2 As shown, a carbon nanotube fiber collection device includes a fiber outlet pipe 1, a mesh belt transfer assembly 2, and an exhaust pipe 6. The fiber outlet pipe 1 and the exhaust pipe 6 are respectively arranged on both sides of the mesh belt transfer assembly 2 in a sealed manner. A carrier gas carrying carbon nanotube fibers is blown out of the fiber outlet pipe 1 into the mesh belt transfer assembly 2, and the carbon nanotube fibers are transferred through the mesh belt transfer assembly 2. The carrier gas is discharged under the action of an exhaust device (such as an exhaust fan) in the exhaust pipe 6, and the exhaust flow rate is 1m / s to 1.5m / s.

[0029] The mesh belt transfer assembly 2 includes a sealing cover 201, to which the fiber outlet pipe 1 and the exhaust pipe 6 are sealed. A pair of rotating guide rollers 202 are rotatably connected in the sealing cover 201. A mesh belt 203 is commonly connected to the outer sides of the two rotating guide rollers 202. The air outlet direction of the fiber outlet pipe 1 faces one side of the mesh belt 203. The mesh belt 203 is driven by the rotating guide rollers 202 to form an annular conveyor belt structure.

[0030] A cooling air pipe is provided between the two rotating guide rollers 202. A plurality of cooling air nozzles 204 are evenly connected and installed on the outer circumference of the cooling air pipe. The cooling air nozzles 204 are arranged in the direction of the air outlet of the fiber outlet pipe 1 and blow out a coolant. In this embodiment, the coolant is liquid nitrogen, which is used to cool the mesh belt 203 near the side of the fiber outlet pipe 1, thereby extending the working life of the mesh belt 203 under high temperature.

[0031] Specifically, generally speaking, the temperature range of the fiber outlet pipe 1 is 300°C to 600°C, and the pipe material is one of a metal pipe, a quartz pipe, and an alumina ceramic pipe;

[0032] The diameter of the rotating guide roller 202 is 80 to 1000 mm, and the length is determined by the size of the fiber outlet pipe 1, which is determined by the carbon nanotube fiber output. The cross-sectional shape of the pipe can be set to be circular or square. The carrier gas flow rate of the carbon nanotube fiber is 0.01 m / s to 1 m / s, and the carrier gas can be argon or nitrogen. Generally speaking, the length of the rotating guide roller 202 should be at least 50 mm greater than the width of the fiber outlet pipe 1 to prevent the carbon nanotube fiber from overflowing from the edge of the mesh belt 203.

[0033] Furthermore, the sealing cover 201 and the mesh belt 203 are made of metal. Preferably, the sealing cover 201 and the mesh belt 203 are made of 310S stainless steel; the rotating guide roller 202 can be a metal guide roller or a magnetic roller; the mesh belt 203 can be rolled from metal fiber wire, or a porous hollow mesh belt formed by openings on the surface of a metal foil; the material of the cooling air nozzle 204 is set to 304 seamless steel pipe.

[0034] Furthermore, a brush stripping assembly 3 for transferring the carbon nanotube fibers on the mesh belt 203 is provided on one side of one of the rotating guide rollers 202 ;

[0035] The brush stripping assembly 3 includes a brush roller 301 rotatably disposed within the sealing cover 201. Brush filaments 302 are disposed on the outer periphery of the brush roller 301. The brush roller 301 and the rotating guide roller 202 have the same rotation direction. At the portion where the brush filaments 302 contact the outer side of the mesh belt 203, the instantaneous tangential velocities of the two are in opposite directions.

[0036] Furthermore, a magnetic roller adsorption assembly 4 is provided below the brush stripping assembly 3. The magnetic roller adsorption assembly 4 includes a hollow roller 401 rotatably mounted in the sealing cover 201. An electromagnet 402 having a fan-shaped cross-section is provided in the hollow roller 401. Air knives 403 are symmetrically provided on both sides of the hollow roller 401. The air outlet of each air knife 403 extends in a direction tangent to the outer side of the hollow roller 401.

[0037] The hollow roller 401 is made of polyurethane rubber, and its length is the same as the width of the mesh belt 203. The power-on time of the electromagnet 402 is adjusted according to the rotation speed of the hollow roller 401. When the electromagnet 402 is below the air knife 403, the power is turned off to release the magnetic attraction effect on the carbon nanotube fibers. When the electromagnet 402 is above the air knife 403, the power is turned on, and the carbon nanotube fibers transferred from the mesh belt 203 by the brush filament 302 are adsorbed on the outer surface of the hollow roller 9 and then enter the product collection component 5 below the magnetic roller adsorption component 4.

[0038] The product collection assembly 5 includes a product collection box 501 and a sealing partition 502. The product collection box 501 is connected to the sealing cover 201. The sealing partition 502 is slidably arranged between the product collection box 501 and the sealing cover 201 to control the opening and closing state of the connecting channel between the two. A glass observation window 503 is provided on the side wall of the product collection box 501.

[0039] The product collecting box 501 and the sealing partition 5 are both made of 304 stainless steel.

[0040] Based on the above-mentioned carbon nanotube fiber collection device, in a specific embodiment, the collection process using the device is as follows:

[0041] First, the sealing partition 502 is opened, and the exhaust device in the exhaust pipe 6 is turned on, with a gas flow rate of 1.2 m / s. The rotating guide roller 202 is driven to rotate, causing the mesh belt 203 to rotate clockwise at a speed of 0.8 m / s, the brush roller 301 to rotate clockwise at a speed of 15 r / s, and the hollow roller 401 to rotate counterclockwise at a speed of 10 r / s. The air knife 403 blows air at a speed of 30 m / s in the direction of the tangential surface of the hollow roller 401. At the same time, the cooling air nozzle 204 blows liquid nitrogen at a speed of 1 m / s toward the mesh belt 203 near the fiber outlet pipe 1.

[0042] Open the fiber outlet pipe 1, the carrier gas flow rate is 1m / s, the carbon nanotube fibers enter the mesh belt 203 on the mesh belt transfer assembly 2 at a speed of 1m / s, and rotate clockwise at a speed of 0.8m / s. Under the action of the brush roller 301, the carbon nanotube fibers fall from the mesh belt 203, and the electromagnet in the hollow sleeve 401 below uses the ferromagnetic properties of the carbon nanotube fibers to adsorb the carbon nanotube fibers on the outer surface of the hollow roller 401, and are then blown by the wind knife 403 into the product collection box 501 below. When it is observed that the carbon nanotube fibers in the product collection box 501 reach a certain amount, close the sealing partition 502, open the door to take out the carbon nanotube fibers in the product collection box 501, then close the product collection box 501, reopen the sealing partition 502, and continue the collection work.

[0043] It should be noted that the synthesis method of the synthesizer connected to one end of the fiber outlet pipe 1 includes a floating catalytic method and an arc method, but is not limited thereto;

[0044] The catalyst for the carbon nanotube fibers is one or a mixture of iron-containing catalysts, cobalt-containing catalysts, and nickel-containing catalysts, but is not limited thereto;

[0045] The collected carbon nanotube fibers are single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, or a mixture of several thereof;

[0046] The present application can adjust the layout structure of the collecting device according to the direction of the fiber outlet pipe 1 of the carbon nanotube production equipment, such as Figure 3 shown.

[0047] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A device for collecting carbon nanotube fibers, characterized in that: The invention comprises a mesh belt transfer assembly (2), wherein a fiber outlet pipe (1) and an exhaust pipe (6) are sealedly connected at symmetrical positions on both sides of the mesh belt transfer assembly (2), and the fiber outlet pipe (1) brings the carbon nanotube fibers to the mesh belt transfer assembly (2) under the flow of carrier gas and the action of the airflow of the exhaust pipe (6); A brush stripping assembly (3) is provided on one side of the mesh belt transfer assembly (2) for stripping and transferring the carbon nanotube fibers on the mesh belt transfer assembly (2); a magnetic roller adsorption assembly (4) is installed below the brush stripping assembly (3) for interstitially adsorbing and transferring the carbon nanotube fibers above to a product collection assembly (5) provided below the brush stripping assembly (3); The mesh belt transfer assembly (2) includes a sealing cover (201), the fiber outlet pipe (1) and the exhaust pipe (6) are both sealed and connected to the sealing cover (201), a pair of rotating guide rollers (202) are rotatably installed in the sealing cover (201), and the two rotating guide rollers (202) jointly drive a closed transmission mesh belt (203), and the carbon nanotube fibers are transferred when they contact the mesh belt (203); A cooling air pipe is provided between the pair of rotating guide rollers (202), and a plurality of cooling air nozzles (204) are evenly connected and installed on the outer circumference of the cooling air pipe. The cooling air nozzles (204) are arranged toward the air outlet direction of the fiber outlet pipe (1) and blow out liquid nitrogen to cool the mesh belt (203) on that side. The brush stripping assembly (3) comprises a brush roller (301) rotatably arranged in a sealing cover (201), a brush filament (302) being arranged on the periphery of the brush roller (301), the brush filament (302) being in contact with the outer side of the mesh belt (203), and the directions of the instantaneous tangential velocities of the two at the contact portion being opposite; The magnetic roller adsorption assembly (4) comprises a hollow roller (401) rotatably mounted in a sealing cover (201), a fan-shaped electromagnet (402) being provided in the hollow roller (401), the on-off time of the electromagnet being matched with the rotation speed of the hollow roller (401), and wind knives (403) being symmetrically provided on both sides of the hollow roller (401), the air outlet of each wind knife (403) extending in a direction tangent to the outer side of the hollow roller (401).

2. The carbon nanotube fiber collecting device according to claim 1, characterized in that: The product collection assembly (5) comprises a product collection box (501) and a sealing partition (502). The product collection box (501) is connected to the sealing cover (201). The sealing partition (502) is slidably arranged between the product collection box (501) and the sealing cover (201) to control the opening and closing state of the communication channel between the two.

3. The carbon nanotube fiber collecting device according to claim 1, characterized in that: The structural form of the mesh belt (203) includes a porous structure formed by rolling metal fiber wire or a porous hollow structure formed by opening holes on the surface of a metal foil.

4. The carbon nanotube fiber collecting device according to claim 1, characterized in that: The hollow roller (401) is made of polyurethane rubber. The length of the hollow roller (401) is the same as the width of the mesh belt (203). The width of the mesh belt (203) exceeds the opening of the fiber outlet pipe (1) by more than 50 mm.

5. A collection method based on the collection device according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Connect the components according to the device and ensure the seal, open the exhaust pipe (6) to form a directional pressure difference state for the entire device, and open the connection channel between the product collection component (5) and the mesh belt transfer component (2); Step 2: Open the fiber outlet pipe (1) to allow the carbon nanotube fibers to enter the collection device under the drive of the carrier gas, and simultaneously start the mesh belt transfer component (2), the brush stripping component (3), and the magnetic roller adsorption component (4), and introduce liquid nitrogen into the device; Step 3: Observe the accumulation of products in the product collection component (5). When the accumulation reaches a certain amount, close the connection channel between the product collection component (5) and the mesh belt transfer component (2), and empty and collect the carbon nanotube fibers in the product collection component (5). After the collection is completed, open the channels between the product collection component (5) and the mesh belt transfer component (2) while ensuring that they are tightly connected.

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