Spinneret plate cleaning method and device based on nano bubble cavitation effect

Abstract

The invention relates to the technical field of maintenance of chemical fiber spinning equipment, in particular to a spinneret plate cleaning method and device based on a nano bubble cavitation effect. The method comprises the following steps: placing or contacting a spinneret plate to be cleaned with a cleaning solution containing high-concentration nanobubbles; the nano bubbles are induced to be broken inside and on the surfaces of the micropores of the spinneret plate, and residual pollutants in the micropores are removed by utilizing cavitation microjet and local physical and chemical effects generated by the breakage of the nano bubbles. The device comprises a cleaning tank, a nano bubble generating unit, a circulating system, a disturbance unit, a pressure adjusting unit, a temperature control adjusting unit, a control system, a spinneret plate placing and cleaning device, a circulating filtering system and a liquid feeding and discharging system. According to the method, high-efficiency, thorough and lossless cleaning is realized by utilizing the physical cavitation microjet and chemical oxidation effect generated by the high-concentration and high-stability nano bubble group in the micropores and on the surface of the spinneret plate, and the method has the remarkable advantages of environmental protection, energy conservation, simplicity and convenience in operation and capability of protecting the precision of the spinneret plate.

Description

Technical Field

[0001] This invention relates to the field of maintenance technology for chemical fiber spinning equipment, specifically to a method for cleaning spinnerets, and more particularly to a method and apparatus for cleaning spinnerets based on the nano-bubble cavitation effect. Background Technology

[0002] As a core precision component of spinning equipment, the spinneret directly determines fiber quality, production efficiency, and cost control. The spinneret's key feature is its micropores; micropore blockage leads to quality problems such as fiber breakage, fuzz, and uneven fineness, necessitating spinneret replacement, severely impacting production line efficiency and hindering cost control. Existing cleaning methods and their disadvantages are as follows: ① Calcination method: This involves burning residues at high temperatures. Disadvantages include high energy consumption, potential spinneret deformation, altered metallographic structure, oxidation, and reduced lifespan; it is not environmentally friendly (waste gas); and it cannot completely remove certain inorganic molten residues or carbides. ② Chemical immersion / ultrasonic method: This involves immersion in strong acids, strong alkalis, or organic solvents, supplemented by ultrasound. Disadvantages include the risk of chemical corrosion (damaging micropore smoothness and pore size); high solvent costs, toxicity, and difficulty in waste liquid treatment; limited cleaning effect of ultrasound on extremely fine pores (<0.2mm), and potential fatigue damage to micropore edges; and long cleaning cycles. ③ Mechanical method (high-pressure water / laser): This refers to high-pressure water jet or laser cleaning. Disadvantages: High-pressure water is ineffective for deep holes and blind holes, and can easily cause physical damage; laser equipment is expensive, complex to operate, and improper parameter control can easily ablate the hole walls. The pain points of existing technologies can be summarized as a contradiction between cleaning effect and protection of spinneret precision and lifespan; high energy consumption, significant pollution, low efficiency, and unsatisfactory cleaning effect on micron-sized micropores. Therefore, there is an urgent need to introduce a new and efficient spinneret cleaning technology. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a spinneret cleaning method and apparatus based on the nanobubble cavitation effect. It is a method and its dedicated apparatus for efficiently, environmentally friendly, and non-destructively removing stubborn polymer residues and impurities from the micropores of a spinneret by utilizing the cavitation effect generated by nanobubbles.

[0004] This method utilizes the physical cavitation microjets and chemical oxidation generated by high-concentration, high-stability nanobubble clusters within and on the surface of the spinneret micropores to achieve efficient, thorough, and non-destructive cleaning. It has significant advantages such as being environmentally friendly, energy-saving, easy to operate, and protecting the precision of the spinneret.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a spinneret cleaning method based on nanobubbling, comprising the following steps:

[0007] S1. Prepare cleaning solution: Prepare a water-based cleaning solution containing surfactants and / or corrosion inhibitors. The cleaning solution is a weakly alkaline or neutral surfactant solution to avoid strong corrosion.

[0008] S2. Generation of Nanobubbles: Using a nanobubble generator, gas (preferably air, oxygen, nitrogen, or a mixture thereof, ozone is mandatory) is introduced into the cleaning solution to generate nanobubbles rich in high concentrations (not less than 10). 8 The cleaning solution contains nanobubbling bubbles per mL and small-particle-size nanobubbles (preferably with an average particle size of 50-500 nm, more preferably 100-300 nm). The nanobubble generating device is preferably a pressurized dissolution and depressurized gas release type, a microporous membrane dispersion type, or a hydraulic cavitation type.

[0009] S3. Circulating cleaning:

[0010] The spinneret to be cleaned is completely immersed in the cleaning solution; and the nano-bubbling cleaning solution is forced to flow through the micropores of the spinneret in a closed circulation system.

[0011] S4. Inducing cavitation effect: During the cleaning process, nanobubbles are induced to rupture inside and on the surface of the spinneret micropores through one or more of the following methods ①-④, and the cavitation microjets and local physicochemical effects generated by their rupture are used to remove residual contaminants in the micropores:

[0012] ① Physical disturbance: Apply low-frequency or high-frequency ultrasound (power controllable to avoid damage), mechanical vibration or fluid pulsation.

[0013] ② Pressure changes: Periodically pressurize and depressurize the cleaning system.

[0014] ③ Temperature control: Appropriately increase the temperature of the cleaning solution (preferably 30-60°C) to reduce the viscosity and surface tension of the liquid, and promote bubble rupture and reaction rate.

[0015] ④ Chemical induction: The active substances in the gas or cleaning liquid inside the bubbles participate in the reaction. The gas contains ozone, and the strong oxidizing properties of ozone nanobubbles are used to synergistically enhance the decomposition of organic residues.

[0016] S5. Cleaning process maintenance: Maintain the operation of steps S3 and S4 for a period of time (30-120 minutes) to allow nanobubbles to be continuously generated, migrate to the depth of micropores, and rupture to generate micro-jet impacts on the pore wall residues. At the same time, the high activity of the gas-liquid interface (free radicals, local high temperature and high pressure) degrades organic matter.

[0017] S6. Rinsing and Drying: After cleaning, remove the spinneret, rinse thoroughly with deionized water to remove residual cleaning solution and impurities, and then dry.

[0018] Furthermore, the water-based cleaning solution comprises the following components: (a) a surfactant system comprising at least one nonionic surfactant selected from alkyl glycosides, block polyethers, and fatty alcohol polyoxyethylene ethers, and optionally an auxiliary surfactant selected from sodium secondary alkyl sulfonate or cocamidopropyl betaine; (b) a pH-adjusting buffer system, wherein the primary buffer is selected from 2-morpholinoethanesulfonic acid (MES), tris(hydroxymethyl)aminomethane (Tris), and a borax-boric acid buffer pair, and the auxiliary adjuster is selected from at least one of triethanolamine, monoethanolamine, and aminotrimethylphosphonic acid, to maintain the pH of the cleaning solution between 6.5 and 9.5; (c) a metal corrosion inhibitor selected from one or more of methylbenzotriazole, molybdate, and silicate; and (d) deionized water.

[0019] Furthermore, the water-based cleaning solution also contains: (e) 0.1%-5% of an organic co-solvent, wherein the organic co-solvent is selected from propylene glycol methyl ether, dipropylene glycol butyl ether, or N-ethyl-2-pyrrolidone; (f) 0.01%-0.1% of a nanobubble stabilizer, wherein the stabilizer is selected from polyvinylpyrrolidone or hydroxyethyl cellulose; and (g) 0.05%-0.5% of a chelating agent, wherein the chelating agent is tetrasodium glutamate diacetate or tetrasodium iminodisuccinate.

[0020] In a second aspect, the present invention provides a spinneret nano-bubbling cleaning device for implementing the above-described method, comprising:

[0021] The cleaning tank has a transparent sliding door for easy observation of its interior. The door is opened and closed using a handle, creating a sealed environment when closed. The tank includes a first and a second perforated shelf, respectively supported by first and second supports on the tank wall. Each shelf has a handle for easy removal. A transparent viewing window is also located on the side of the tank for further observation of the cleaning process. It also includes a nanobubble generating unit for introducing gas into the cleaning liquid and generating nanobubbles; a circulation system, including a circulation pipeline with a circulation pump, a circulation pipeline flow meter and a first pneumatic valve upstream of the circulation pump, and a check valve downstream, for circulating the cleaning liquid containing nanobubbles within the cleaning tank and / or the micropores of the spinneret; and a control system, including a touch screen display, a PLC or microcontroller, for controlling the start and stop of the circulation pump, bubble generator, disturbance unit, pressure regulating unit, and heating unit, parameter setting (pressure, temperature, time, ultrasonic power / frequency), and process monitoring, and a three-color alarm for indication and alarm.

[0022] Furthermore, it also includes a spinneret placement and cleaning device for fixing the spinneret and guiding the cleaning fluid through its micropores. A quick-release connector allows for easy connection of the nanobubble flow delivery pipeline to the manifold. The manifold ensures that 100% of the nanobubble cleaning fluid flows through the spinneret's micropores (rather than flowing around them), improving cleaning efficiency. An internal mesh guide plate evenly distributes the input nanobubble cleaning fluid across the entire back of the spinneret, preventing excessively high / low flow velocities in certain areas. The manifold and mesh guide plate ensure 100% flow of the nanobubble cleaning fluid through the spinneret's micropores (rather than flowing around them), improving cleaning efficiency. The spinneret placement bracket is fixed to the outer upper part of the manifold, with an elastic rubber sealing block on the inner side to protect the spinneret and provide a seal. A rotatable clamp is fixed to the spinneret placement bracket with fixing bolts and nuts, securing the spinneret once it is in place.

[0023] Furthermore, it also includes a disturbance unit, which is one or more of an ultrasonic generator, a vibrator, or a pulsating flow generator, installed at the bottom or side wall of the cleaning tank.

[0024] Furthermore, it also includes a pressure regulating unit, which contains a pump, a pressure sensor, and a second pneumatic valve for pressurizing and / or depressurizing the closed cleaning system.

[0025] Furthermore, it also includes a heating and temperature control unit, which includes a temperature controller, a temperature sensor, and a heating rod, used to control the temperature of the cleaning fluid.

[0026] Furthermore, the nanobubble generating unit employs a microporous membrane dispersion type, a swirling shear type, a pressurized dissolution depressurization release type, or a hydraulic cavitation type generator.

[0027] Furthermore, it also includes a filtration system, which includes a filter and a first gate valve, used to circulate and filter out insoluble impurities in the cleaning tank.

[0028] Furthermore, it also includes a liquid inlet system, which includes a liquid inlet pump, a third pneumatic valve, and a liquid inlet pipeline flow meter for replenishing clean liquid in the tank; and a liquid outlet system, which includes a liquid outlet pipeline flow meter and a second gate valve for discharging liquid.

[0029] Furthermore, the transparent sliding doors and transparent windows are made of high-temperature resistant acrylic; the perforated shelves are made of corrosion-resistant metal (such as 316L stainless steel); and the flow collection hood and mesh guide plate are made of engineering plastic (such as PEEK).

[0030] The spinneret cleaning method and apparatus based on the nano-bubble cavitation effect provided in this application can achieve the following beneficial technical effects through innovation:

[0031] 1. Highly efficient and thorough: The tiny size of the nanobubbles allows them to easily penetrate deep into the micropores of the spinneret. The localized microjet streams (up to hundreds of meters per second) and instantaneous high pressure (up to hundreds of MPa) generated by the bursting of these bubbles powerfully peel away and pulverize stubborn residues (polymer melts, carbides, additives, etc.) adhering to the pore walls. Ozone nanobubbles also generate strong oxidizing free radicals, chemically degrading organic pollutants. This synergistic effect ensures thorough cleaning without any blind spots, resulting in a high level of cleanliness.

[0032] 2. Non-destructive cleaning: The micro-jet's effective range is extremely small, and its energy is precisely applied to the interface between residue and the orifice wall, avoiding macroscopic mechanical damage (such as high-pressure water or mechanical scraping) or thermal damage (such as calcination) to the spinneret material (especially the edges of the micro-orifices). The cleaning is primarily physical, with a low risk of chemical corrosion, maximizing the protection of the spinneret's original precision (orifice diameter, orifice shape, and surface finish) and service life.

[0033] 3. Environmental protection and safety: It mainly uses water-based cleaning solutions (with the addition of environmentally friendly surfactants), which eliminates or greatly reduces the use of strong acids, strong alkalis and toxic organic solvents. Waste liquid treatment is simple, reducing environmental pollution and health risks to operators.

[0034] 4. Energy saving and consumption reduction: High cleaning efficiency, which can shorten cleaning time. It can be operated at room temperature or medium temperature, without the need for high temperature.

[0035] 5. Easy to operate and highly automated: The device can be integrated and automatically controlled. The cleaning process parameters (bubble concentration / particle size, pressure, temperature, time, disturbance intensity) are easy to control accurately, with good repeatability, reducing the intensity of manual operation and skill requirements. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present application, but not all embodiments. Other drawings can be obtained from these drawings by those skilled in the art without inventive effort.

[0037] Figure 1 This is a schematic diagram of the structure of the spinneret nano-bubbling cleaning device of the present invention;

[0038] Figure 2 This is a top view of the spinneret nano-bubble cleaning device;

[0039] Figure 3 This is a schematic diagram of the spinneret clamp and flow guiding structure;

[0040] Figure 4This is a schematic diagram illustrating the principle of nanobubbles migrating and rupturing within the micropores of a spinneret to generate microjets that remove residues.

[0041] Wherein: 1-Cleaning tank; 1a-Transparent sliding door; 1b-Sliding door handle; 1c-First perforated shelf; 1d-First support; 1e-First shelf handle; 1f-Second perforated shelf; 1g-Second support; 1h-Second shelf handle; 1i-Liquid surface; 1j-Transparent window; 2-Nano bubble generating unit; 3a-Circulation pump; 3b-Circulation pipeline; 3c-Circulation pipeline flow meter; 3d-First pneumatic valve; 3e-Check valve; 4a-Ultrasonic generator; 4b-Vibrator; 4c-Pulsating flow generator; 5a-Air pump; 5b-Pressure sensor; 5c-Second pneumatic valve; 6a-Temperature controller; 6b-Temperature sensor; 6c-Heating rod; 7-Control system; 7a-Touchscreen display; 7b-Three-color alarm; 8-Spinneret placement and cleaning device; 8a-Nano bubble flow delivery pipeline; 8b-Quick-release connector; 8c-Flow collector; 8d-Flow guide plate; 8e-Spinneret placement bracket; 8f-Rotable clamp; 8g-Fixing nut; 8h-Fixing bolt; 8i-Elastic rubber sealing block; 8j-Spinneret; 9a-Filter; 9b-First gate valve; 10a-Inlet pump; 10b-Third pneumatic valve; 10c-Inlet pipeline flow meter; 11a-Drain pipeline flow meter; 11b-Second gate valve. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0043] The spinneret cleaning device based on the nanobubble cavitation effect of this invention includes:

[0044] The cleaning tank 1 has an acrylic transparent sliding door 1a for easy observation of the interior. The door 1a is opened and closed using a handle 1b, forming a sealed enclosure when closed. The cleaning tank 1 includes a first perforated shelf 1c and a second perforated shelf 1f, made of corrosion-resistant metal such as 316L stainless steel, which are respectively placed on a first support 1d and a second support 1g on the wall of the cleaning tank 1. The perforated shelves 1c and 1f each have a first shelf handle 1e and a second shelf handle 1h for easy removal. An acrylic transparent viewing window 1j is also located on the side of the cleaning tank 1, also for easy observation of the cleaning process inside. It also includes a nanobubble generating unit 2, which employs a microporous membrane dispersion type, swirling shear type, pressurized dissolution depressurization gas release type, or hydraulic cavitation type generator to introduce gas into the cleaning liquid and generate nanobubbles; a circulation system 3, including a circulation pipeline 3b with a circulation pump 3a, a circulation pipeline flow meter 3c and a first pneumatic valve 3d upstream of the circulation pump 3a, and a check valve 3e downstream, to circulate the cleaning liquid containing nanobubbles in the cleaning tank and / or the micropores of the spinneret; and a control system 7, including a touch screen display 7a, a PLC or a microcontroller, to control the start and stop of the circulation pump, bubble generator, disturbance unit, pressure regulation unit, and heating unit, parameter setting (pressure, temperature, time, ultrasonic power / frequency), and process monitoring; and a three-color alarm 7b for indication and alarm.

[0045] It also includes a spinneret placement and cleaning device 8 for fixing the spinneret and guiding the cleaning fluid through its micropores. A quick-release connector 8b connects the nanobubble flow delivery pipeline 8a to the flow collector 8c. The flow collector 8c ensures that 100% of the nanobubble cleaning fluid flows through the spinneret micropores (rather than flowing around them), improving cleaning efficiency. An internal mesh guide plate 8d evenly distributes the input nanobubble cleaning fluid across the entire back of the spinneret, preventing excessively high / low flow velocities in certain areas. The flow collector 8c and the mesh guide plate 8d are made of engineering plastics (such as PEEK) to ensure 100% flow of the nanobubble cleaning fluid through the spinneret micropores (rather than flowing around them), improving cleaning efficiency. A spinneret placement bracket 8e is fixed to the upper outer side of the flow collector 8c. An elastic rubber sealing block 8i is installed inside 8e to protect the spinneret 8j and provide a seal. The rotatable clamp 8f is fixed to the spinneret placement bracket 8e by fixing bolts 8h and fixing nuts 8g. Once the spinneret is in place, it can be fixed in place.

[0046] It also includes a disturbance unit 4, which is one or more of an ultrasonic generator 4a, a vibrator 4b, or a pulsating flow generator 4c, and is installed at the bottom or side wall of the cleaning tank.

[0047] It also includes a pressure regulating unit 5, which contains a pump 5a, a pressure sensor 5b, and a second pneumatic valve 5c, for pressurizing and / or depressurizing the closed cleaning system.

[0048] It also includes a heating temperature control unit 6, which includes a temperature controller 6a, a temperature sensor 6b, and a heating rod 6c, used to control the temperature of the cleaning fluid.

[0049] It also includes a filtration system 9, which includes a filter 9a and a first gate valve 9b, for circulating and filtering out insoluble impurities in the cleaning tank.

[0050] It also includes a liquid inlet system 10, which includes a liquid inlet pump 10a, a third pneumatic valve 10b, and a liquid inlet pipeline flow meter 10c, for replenishing clean liquid in the tank; and a liquid outlet system 11, which includes a liquid outlet pipeline flow meter 11a and a second gate valve 11b, for discharging liquid.

[0051] The spinneret cleaning method includes the following steps:

[0052] A water-based cleaning solution containing a weakly alkaline or neutral surfactant is prepared. A nanobubble generator is used to introduce a gas (preferably air, oxygen, nitrogen, or a mixture thereof) and ozone into the cleaning solution, generating a solution rich in high concentrations (not less than 10). 8 The cleaning solution uses nanobubbling particles (bubbles / mL) with a particle size of 50-500 nm. The preferred nanobubble generator is a pressurized dissolution / depressurized release type, a microporous membrane dispersion type, or a hydraulic cavitation type. The spinneret to be cleaned is completely immersed in the cleaning solution, and the nanobubbling cleaning solution is forced to flow through the micropores of the spinneret in a closed circulation system. During the cleaning process, nanobubbles are induced to rupture inside and on the surface of the spinneret micropores through one or more of the following methods, utilizing the cavitation microjets and local physicochemical effects generated by their rupture to remove residual contaminants within the micropores:

[0053] Physical disturbance: Applying low-frequency or high-frequency ultrasound (power controllable, avoids damage, optional), mechanical vibration, or fluid pulsation.

[0054] Pressure changes: Periodically pressurize and depressurize the cleaning system.

[0055] Temperature control: The temperature of the cleaning solution should be appropriately increased to 30-60°C to reduce the viscosity and surface tension of the liquid, and promote bubble rupture and reaction rate.

[0056] Chemical induction: The active substances in the gas or cleaning liquid inside the bubbles participate in the reaction. The gas contains ozone, and the strong oxidizing properties of ozone nanobubbles are used to synergistically enhance the decomposition of organic residues.

[0057] Maintain operation for 30-120 minutes to allow nanobubbles to continuously generate, migrate to the depths of micropores, and rupture to generate microjets that impact the pore wall residues. Simultaneously, utilize the high activity of the gas-liquid interface (free radicals, local high temperature and pressure) to degrade organic matter. After cleaning, remove the spinneret, rinse thoroughly with deionized water to remove residual cleaning solution and impurities, and then dry. Perform throughput testing and put it into use. Use a metallographic microscope to observe spinneret scratches and micropore smoothness.

[0058] The above-described contents can be implemented individually or in various combinations, and these variations are all within the scope of protection of this application.

[0059] Example 1

[0060] A water-based cleaning solution (pH 9.5) containing a weakly alkaline surfactant was prepared. The water-based cleaning solution contained the following components: (a) a surfactant system consisting of a compound of alkyl glycosides, block polyethers, and cocamidopropyl betaine; (b) a primary buffer consisting of a borax-boric acid buffer pair with a concentration of 0.5%, and an auxiliary buffer consisting of triethanolamine with a mass fraction of 0.5% in the cleaning solution; (c) methylbenzotriazole as a metal corrosion inhibitor; (d) deionized water; (e) 2% propylene glycol methyl ether as an organic additive; (f) 0.05% nanobubble stabilizer selected from polyvinylpyrrolidone; and (g) 0.3% tetrasodium diacetate glutamate as a chelating agent.

[0061] Using a nanobubble generator, air and ozone are introduced into the cleaning solution to generate a high-concentration nanobubble cleaning solution with a particle size of 400nm. The nanobubble generator is preferably a microporous membrane dispersion generator. The spinneret to be cleaned is completely immersed in the cleaning solution, and the nanobubble cleaning solution is forced to flow through the micropores of the spinneret in a closed circulation system. During the circulating cleaning process, low-frequency ultrasonic vibration is applied, and the temperature is controlled at 60°C to induce the nanobubbles to rupture inside and on the surface of the spinneret's micropores. The air generated by the rupture is utilized... Micro-jet cleaning and localized physicochemical effects remove residual contaminants from micropores. This process is maintained for 50 minutes, allowing nanobubbles to continuously generate, migrate deep into the micropores, and rupture to create micro-jet impacts on the pore walls, removing residues. Simultaneously, the highly active gas-liquid interface (free radicals, localized high temperature and pressure) degrades organic matter. After cleaning, the spinneret is removed, thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, and then dried. The pass rate is 97.23%, and the success rate for machine use is 99%. After 20 cycles, the spinneret surface is free of scratches, and the micropores are smooth and round.

[0062] Example 2

[0063] A water-based cleaning solution (pH 6.5) containing a neutral surfactant was prepared. The water-based cleaning solution contained the following components: (a) a surfactant system consisting of a compound of alkyl glycoside and sodium secondary alkyl sulfonate; (b) a primary buffer consisting of a compound of MES and Tris with a molar ratio of 1:1, and an auxiliary buffer consisting of triethanolamine with a mass fraction of 0.5% in the cleaning solution; (c) methylbenzotriazole as a metal corrosion inhibitor; (d) deionized water; (e) 2% propylene glycol methyl ether as an organic additive; (f) 0.05% nanobubble stabilizer selected from polyvinylpyrrolidone; and (g) 0.3% tetrasodium diacetate of glutamate as a chelating agent.

[0064] Using a nanobubble generator, an oxygen-ozone mixture is introduced into the cleaning fluid to generate a high-concentration nanobubble cleaning fluid with a particle size of 200nm. The nanobubble generator is a vortex shear type generator. The spinneret to be cleaned is completely immersed in the cleaning fluid, and the nanobubble cleaning fluid is forced to flow through the micropores of the spinneret in a closed circulation system. During the circulating cleaning process, periodic pressure pulsations are applied, and the temperature is controlled at 40°C to induce the nanobubbles to rupture inside and on the surface of the spinneret micropores. The air bubbles generated by their rupture are utilized... Micro-jet cleaning and localized physicochemical effects remove residual contaminants from micropores. This process is maintained for 70 minutes, allowing nanobubbles to continuously generate, migrate deep into the micropores, and rupture to create micro-jet impacts on the pore walls, removing residues. Simultaneously, the highly active gas-liquid interface (free radicals, localized high temperature and pressure) degrades organic matter. After cleaning, the spinneret is removed, thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, and then dried. The pass rate is 98.71%, and the success rate of machine use is 100%. After 20 cycles of use, the spinneret surface is free of scratches, and the micropores are smooth and round.

[0065] Example 3

[0066] A water-based cleaning solution (pH 7.5) containing a neutral surfactant was prepared. The water-based cleaning solution contained the following components: (a) a surfactant system consisting of a compound of alkyl glycosides, block polyethers, fatty alcohol polyoxyethylene ethers, and cocamidopropyl betaine; (b) a primary buffer consisting of a compound of MES and Tris with a molar ratio of 1:1, and an auxiliary buffer consisting of triethanolamine with a mass fraction of 0.4% in the cleaning solution; (c) methylbenzotriazole as a metal corrosion inhibitor; (d) deionized water; (e) 2% dipropylene glycol butyl ether as an organic additive; (f) 0.05% nanobubble stabilizer selected from polyvinylpyrrolidone; and (g) 0.3% tetrasodium diacetate glutamate as a chelating agent.

[0067] Using a nanobubble generator, an air-ozone mixture is introduced into the cleaning fluid to generate a high-concentration nanobubble cleaning fluid with a particle size of 200nm. The nanobubble generator employs a vortex shear type generator. The spinneret to be cleaned is completely immersed in the cleaning fluid, and the nanobubble cleaning fluid is forced to flow through the micropores of the spinneret in a closed circulation system. During the circulating cleaning process, periodic pressure pulsations are applied, and the temperature is controlled at 50°C to induce the nanobubbles to rupture inside and on the surface of the spinneret micropores. The cavitation generated by these ruptures is utilized. Micro-jet and local physicochemical effects remove residual contaminants within the micropores. This process is maintained for 110 minutes, allowing nanobubbles to continuously generate, migrate deep into the micropores, and rupture to create micro-jet impacts on the pore walls, while simultaneously utilizing the highly active gas-liquid interface (free radicals, local high temperature and pressure) to degrade organic matter. After cleaning, the spinneret is removed, thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, and then dried. The pass rate is 99.30%, and the success rate of use is 100%. After 20 cycles of use, the spinneret surface is free of scratches, and the micropores are smooth and round.

[0068] Comparative Example 1

[0069] Using deionized water as a cleaning solution, nitrogen and ozone are introduced into the cleaning solution through a nanobubble generator to produce a high-concentration, 600nm nanobubble cleaning solution. The nanobubble generator is a hydraulic cavitation generator. The spinneret to be cleaned is completely immersed in the cleaning solution, and the nanobubble cleaning solution is forced to flow through the micropores of the spinneret in a closed circulation system. During the circulation cleaning process, low-power high-frequency ultrasound is applied, and the temperature is controlled at 50°C to induce the nanobubbles to rupture inside and on the surface of the spinneret micropores. The resulting nanobubbles are then utilized... Cavitation microjets and localized physicochemical effects remove residual contaminants within the micropores. This process is maintained for 70 minutes, allowing nanobubbles to continuously generate, migrate deep into the micropores, and rupture to create microjets that impact the pore walls and remove residues. Simultaneously, the highly active gas-liquid interface (free radicals, localized high temperature and pressure) degrades organic matter. After cleaning, the spinneret is removed, thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, and then dried. The pass rate is 95.20%, and those that do not meet the pass rate are not used. After repeated cleaning and 20 cycles of use, the spinneret surface is free of scratches, and the micropores are smooth and round.

[0070] Comparative Example 2

[0071] The spinneret was cleaned for 120 minutes with 100℃ DMSO organic solvent and enhanced alkali soaking, supplemented by ultrasonic vibration. After cleaning, the spinneret was removed and thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, and then dried. The pass rate was 90.11%, and the spinneret was not used because the pass rate was not up to standard. After repeated cleaning and 20 cycles of use, the surface of the spinneret showed slight scratches and slight burrs around the micropores.

[0072] Comparative Example 3

[0073] A water-based cleaning solution (pH 7.5) containing a neutral surfactant was prepared. The water-based cleaning solution contained the following components: (a) a surfactant system consisting of a compound of alkyl glycosides, block polyethers, fatty alcohol polyoxyethylene ethers, and cocamidopropyl betaine; (b) a primary buffer consisting of a compound of MES and Tris with a molar ratio of 1:1, and an auxiliary buffer consisting of triethanolamine with a mass fraction of 0.4% in the cleaning solution; (c) methylbenzotriazole as a metal corrosion inhibitor; (d) deionized water; (e) 2% dipropylene glycol butyl ether as an organic additive; (f) 0.05% nanobubble stabilizer selected from polyvinylpyrrolidone; and (g) 0.3% tetrasodium diacetate glutamate as a chelating agent.

[0074] An air-air mixture is introduced into the cleaning fluid using a nanobubble generator to produce a cleaning fluid rich in high-concentration nanobubbles with a particle size of 600 nm. The nanobubble generator employs a vortex shearing type. The spinneret to be cleaned is completely immersed in the cleaning fluid, and the nanobubble cleaning fluid is forced to flow through the micropores of the spinneret in a closed circulation system. During the circulating cleaning process, the temperature is controlled at 70°C to induce the nanobubbles to rupture inside and on the surface of the spinneret micropores. The cavitation microjets generated by their rupture and localized physical and chemical reactions are utilized. The chemical effect removes residual contaminants within the micropores. Maintaining this process for 20 minutes allows for the continuous generation of nanobubbles, their migration to the depths of the micropores, and their rupture to generate microjet streams that impact the pore walls and remove residue. Simultaneously, the highly active gas-liquid interface (free radicals, localized high temperature and pressure) degrades organic matter. After cleaning, the spinneret is removed and thoroughly rinsed with deionized water to remove residual cleaning solution and impurities, then dried. The pass rate was 93.20%, and products with a lower pass rate were not used. After repeated cleaning and 20 cycles, the spinneret surface was free of scratches, and the micropores were smooth and round.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for cleaning a spinneret, characterized in that, Includes the following steps: S1. Prepare cleaning solution: Prepare a water-based cleaning solution containing surfactants and / or corrosion inhibitors, wherein the cleaning solution is a weakly alkaline or neutral surfactant-containing solution; S2. Generating nanobubbles: Using a nanobubble generator, ozone or a mixture of ozone and other gases is introduced into the cleaning liquid to generate ozone at a concentration of not less than 10. 8 Nanobubbling cleaning solution with small-diameter nanobubbles per mL and an average particle size of 50-500 nm; S3. Circulating cleaning: The spinneret to be cleaned is completely immersed in the cleaning solution; and the nano-bubbling cleaning solution is forced to flow through the micropores of the spinneret in a closed cleaning system. S4. Inducing cavitation effect: During the cleaning process, the nanobubbles are induced to rupture inside and on the surface of the spinneret micropores through one or more induction methods. The cavitation microjets generated by their rupture and the local physicochemical effects are used to remove residual contaminants in the micropores. The specific induction method is as follows: Physical disturbance: applying low-frequency or high-frequency ultrasound, mechanical vibration, or fluid pulsation; Pressure changes: Periodically pressurize and depressurize the cleaning system; Temperature control: Increase the temperature of the cleaning solution by 30-60°C to reduce the viscosity and surface tension of the liquid, and promote bubble rupture and reaction rate. Chemical induction: The active substances in the gas or cleaning liquid inside the bubbles participate in the reaction. The gas contains ozone. The strong oxidizing properties of ozone nanobubbles are used to synergistically enhance the decomposition of organic residues. S5. Cleaning process maintenance: Maintain the operation of steps S3 and S4 for 30-120 minutes to allow nanobubbles to be continuously generated, migrate to the depth of micropores, rupture and generate micro-jet impacts on the pore wall residues, while utilizing free radicals and local high temperature and high pressure to degrade organic matter. S6. Rinsing and Drying: After cleaning, remove the spinneret, rinse thoroughly with deionized water to remove residual cleaning solution and impurities, and then dry.

2. The spinneret cleaning method according to claim 1, characterized in that, The water-based cleaning solution comprises the following components: (a) A surfactant system comprising at least one nonionic surfactant selected from alkyl glycosides, block polyethers, and fatty alcohol polyoxyethylene ethers, and optionally an auxiliary surfactant selected from sodium secondary alkyl sulfonate or cocamidopropyl betaine; (b) a pH-adjusting buffer system, wherein the primary buffer is selected from 2-morpholinoethanesulfonic acid (MES), tris(hydroxymethyl)aminomethane (Tris), and a borax-boric acid buffer pair, and the auxiliary adjuster is selected from at least one of triethanolamine, monoethanolamine, and aminotrimethylphosphonic acid, to maintain the pH of the cleaning solution between 6.5 and 9.5; c) Metal corrosion inhibitor, selected from one or more of methylbenzotriazole, molybdate, and silicate; (d) deionized water; preferably, the water-based cleaning solution further comprises: (e) 0.1%-5% organic co-solvent, the organic co-solvent being selected from propylene glycol methyl ether, dipropylene glycol butyl ether, or N-ethyl-2-pyrrolidone; (f) 0.01%-0.1% nanobubble stabilizer, the stabilizer being selected from polyvinylpyrrolidone or hydroxyethyl cellulose; (g) 0.05%-0.5% chelating agent, the chelating agent being tetrasodium glutamate diacetate or tetrasodium iminodisuccinate.

3. A spinneret cleaning device based on nanobubble cavitation effect for use in the method of claim 1, characterized in that, include: The cleaning tank (1) is equipped with a transparent sliding door (1a) to facilitate observation of the tank. The sliding door (1a) is opened and closed by the sliding door handle (1b) on (1a), and a sealed state is formed after closing. The cleaning tank (1) includes a first hollow shelf (1c) and a second hollow shelf (1f), which are respectively placed on the first support (1d) and the second support (1g) of the wall of the cleaning tank (1); the first hollow shelf (1c) and the second hollow shelf (1f) are respectively provided with a first shelf handle (1e) and a second shelf handle (1h) to facilitate the removal of the shelf; The cleaning tank (1) also has a transparent viewing window (1j) on the side, which is used to facilitate observation of the cleaning situation inside the cleaning tank (1); It also includes a nanobubble generating unit (2) for introducing gas into the cleaning liquid and generating nanobubbles; The circulation system (3) includes a circulation pipeline (3b) with a circulation pump (3a) on it. Upstream of the circulation pump (3a) are a circulation pipeline flow meter (3c) and a first pneumatic valve (3d), and downstream are a check valve (3e) for circulating the cleaning liquid containing nanobubbles in the cleaning tank and / or the micropores of the spinneret. The system (7) includes a touch screen (7a), a PLC or microcontroller, for controlling the start and stop of the circulating pump, bubble generator, disturbance unit, pressure regulating unit and heating unit, parameter setting and process monitoring. The system (7) also includes a three-color alarm (7b) for indication and alarm.

4. The apparatus according to claim 2, characterized in that, It also includes a spinneret placement and cleaning device (8) for fixing the spinneret and guiding the cleaning fluid through its micropores. The nanobubble flow delivery pipeline (8a) is conveniently connected to the manifold (8c) via a quick-release connector (8b). The manifold (8c) ensures that 100% of the nanobubble cleaning fluid flows through the micropores of the spinneret. A mesh guide plate (8d) is installed inside the manifold (8c) to evenly disperse the input nanobubble cleaning fluid to the entire back of the spinneret. The manifold (8c) and the mesh guide plate (8d) The flow plate (8d) ensures that the nano-bubbling cleaning fluid flows 100% through the micropores of the spinneret; the spinneret placement bracket (8e) is fixed to the outer side of the upper end of the flow collector (8c), and the inner side of the spinneret placement bracket (8e) is equipped with an elastic rubber sealing block (8i) to protect the spinneret (8j) and provide a sealing function; the rotatable clamp (8f) is fixed to the spinneret placement bracket (8e) by fixing bolts (8h) and fixing nuts (8g) to fix the spinneret after it is placed.

5. The apparatus according to claim 2, characterized in that, It also includes a disturbance unit (4), which is one or more of an ultrasonic generator (4a), a vibrator (4b) or a pulsating flow generator (4c), and is installed at the bottom or side wall of the cleaning tank.

6. The apparatus according to claim 2, characterized in that, It also includes a pressure regulating unit (5), which includes an air pump (5a), a pressure sensor (5b), and a second pneumatic valve (5c) for pressurizing and / or depressurizing the closed cleaning system; it also includes a heating temperature control unit (6), which includes a temperature controller (6a), a temperature sensor (6b), and a heating rod (6c) for controlling the temperature of the cleaning fluid.

7. The apparatus according to claim 2, characterized in that, The nanobubble generating unit (2) adopts a microporous membrane dispersion type, swirling shear type, pressurized dissolution depressurization release type or hydraulic cavitation type generator.

8. The apparatus according to claim 2, characterized in that, It also includes a filtration system (9), which includes a filter (9a) and a first gate valve (9b) for circulating and filtering out insoluble impurities in the cleaning tank.

9. The apparatus according to claim 2, characterized in that, It also includes a liquid inlet system (10), which includes a liquid inlet pump (10a), a third pneumatic valve (10b) and a liquid inlet pipeline flow meter (10c) for replenishing clean liquid in the tank; it also includes a liquid outlet pipeline flow meter (11a) and a second gate valve (11b) in the liquid outlet system (11) for discharging liquid.

10. The apparatus according to claim 2, characterized in that, The transparent sliding door (1a) and transparent window (1j) are made of transparent material, using high-temperature resistant acrylic; the first hollow shelf (1c) and the second hollow shelf (1f) are made of corrosion-resistant 316L stainless steel; the flow collector (8c) and the mesh guide plate (8d) are made of engineering plastic PEEK.

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