Gradient nanofiber filtration and corrosion protection structure on valve core and valve sleeve surface and its preparation method

Abstract

This invention belongs to the technical field of precision fluid control equipment, specifically relating to a gradient nanofiber filtration and anti-corrosion structure for valve core and valve sleeve surfaces and its preparation method. The structure includes a gradient nanofiber filtration layer disposed in the valve inlet region, valve core return region, and / or high-wear region of the valve sleeve. Along the fluid flow direction, it sequentially includes a micron-scale main fiber layer, a submicron-scale transition fiber layer, and a nano-scale short fiber layer. This layer is fixed to the inner wall of the valve body or the surface of a local guide channel via adhesion, hot-pressing composite, or in-situ deposition. During preparation, based on the electrohydrodynamic multi-peak splitting mechanism induced by high-dipole-moment functional molecules, the single jet is transformed into a multi-peaked bifurcated jet by controlling the electrocapillary number CaE > 1, forming a multi-scale gradient nanofiber network. This achieves deep filtration and synergistic protection against tiny wear particles and metal corrosion debris in the micro-gap region. This invention has the advantages of high filtration efficiency, low flow resistance, excellent anti-corrosion performance, and the ability to be integrated with the valve internal structure.

Description

Technical Field

[0001] This invention relates to the field of precision fluid control equipment technology, specifically to a gradient nanofiber filtration and corrosion protection structure on the surface of a valve core and valve sleeve, and its preparation method. Background Technology

[0002] As high-end hydraulic systems, pneumatic control systems, and precision fluid equipment develop towards higher precision, miniaturization, and longer lifespan, the stability and reliability of the micro-clearance moving parts inside precision valves are becoming increasingly prominent issues. The valve core and valve sleeve typically have only a micrometer-level clearance, making it easy for tiny wear particles, metal corrosion debris, moisture, and oxidation byproducts in the fluid to enter this gap. This can lead to problems such as jamming, increased internal leakage, delayed response, and surface pitting, severely impacting the control accuracy and service life of precision valves.

[0003] Traditional technologies primarily intercept particles using external filter elements, sintered metal filters, and microporous filters, combined with surface strengthening methods such as chromium plating, nitriding, or diamond-like carbon coatings to improve valve body corrosion resistance. In recent years, electrospun nanofiber membranes have been introduced into the liquid filtration field, utilizing nanoscale fiber structures to enhance particle capture efficiency. However, most existing electrospun nanofiber membranes employ a single-scale, continuous stacking of long fibers, resulting in relatively uniform pore size distribution. Relying mainly on surface filtration mechanisms, they are prone to clogging in localized areas, making it difficult to achieve both high filtration efficiency and low flow resistance. Furthermore, existing nanofiber filter layers are mostly placed externally as independent filter elements, lacking integrated design tailored to the internal flow field characteristics and micro-gap motion pairs of precision valves. This makes it difficult to provide precise localized protection for valve inlet areas, high-wear areas, and backflow dead zones. In addition, existing anti-corrosion technologies mainly rely on metal surface plating or coating reinforcement, typically providing only passive protection to the valve body surface, lacking an active anti-corrosion mechanism that works synergistically with the filtration structure.

[0004] Therefore, there is an urgent need to develop a novel nanofiber filtration and protection structure that combines gradient deep filtration, corrosion inhibition, and in-valve integration capabilities. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a gradient nanofiber filtration and anti-corrosion structure for valve core and valve sleeve surface and its preparation method. This structure can achieve integrated integration of gradient nanofiber filtration layer and valve internal structure, and actively regulate jet splitting behavior through material molecular design to construct a multi-scale gradient pore network, thereby synergistically improving filtration efficiency, reducing flow resistance and enhancing anti-corrosion performance.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a gradient nanofiber filtration and corrosion-resistant structure for the surface of a valve core and valve sleeve, comprising: Gradient nanofiber filter layer disposed on the surface of valve core and / or valve sleeve; And local flow channels and swirling buffers disposed on the surface of the valve core and / or valve sleeve, adjacent to the gradient nanofiber filter layer; The gradient nanofiber filter layer is composed of a multi-scale gradient pore network consisting of micron-scale main fibers, submicron-scale transition fibers, and nano-scale short fibers. Along the fluid flow direction, the average pore size of the gradient nanofiber filter layer decreases step by step, forming the main channel filtration zone, the particle interception zone and the deep deposition zone in sequence. The localized flow channel is configured to alter the local fluid velocity distribution and particle migration path, deflecting particles towards the gradient nanofiber filter layer. The swirling buffer zone is configured to create a low-speed swirling flow field, extending the residence time of particles on the surface of the gradient nanofiber filter layer. By arranging the gradient nanofiber filter layer adjacent to the localized flow channel and the swirling buffer zone, a three-in-one synergistic protection structure is formed. The gradient nanofiber filter layer consists of a multi-scale gradient pore network composed of micron-sized main fibers, submicron-sized transition fibers, and nano-sized short fibers. The average pore size decreases progressively along the fluid flow direction, sequentially forming a main channel filtration zone, a particle interception zone, and a deep deposition zone. This enables progressive interception and deep deposition of particles of different sizes, from coarse to fine filtration, balancing high filtration efficiency with low flow resistance, and avoiding the clogging defects of traditional surface filters. Localized flow channels alter the local fluid velocity distribution and particle migration path, causing particles to deflect towards the gradient nanofiber filter layer. A swirling buffer zone creates a low-speed swirling flow field, extending the residence time of particles on the surface of the gradient nanofiber filter layer. These two elements synergistically enhance the contact probability between particles and the fiber layer, significantly improving particle capture efficiency. This structure can be directly integrated into the valve core and / or valve sleeve surface, achieving precise localized filtration and protection for the micro-gap areas of precision valves within a limited space. In some embodiments, the gradient nanofiber filter layer is disposed in the valve inlet region, the valve core return region, and / or the high-wear region of the valve sleeve. Distributing the gradient nanofiber filter layer in these regions addresses critical areas where particles easily enter, fluid disturbance is strong, and wear risk is high. By concentrating the gradient nanofiber filter layer in these locations, precise protection can be provided for the particle source path and vulnerable areas, effectively reducing the probability of particles entering the valve core and valve sleeve mating gap, improving the targeting and efficiency of protection, and reducing ineffective coverage of non-critical areas.

[0007] In some embodiments, the thickness of the gradient nanofiber filter layer is 50 μm to 500 μm. Limiting the thickness of the gradient nanofiber filter layer to 50 μm to 500 μm provides sufficient space for multi-scale fiber stacking and deep filtration capacity, ensuring that particles undergo sufficient migration, interception, and deposition within the fiber layer. Simultaneously, controlling the thickness within a suitable range avoids affecting the internal flow channel space of the valve and the fitting clearance of moving parts due to excessive thickness, ensuring structural compactness and installation adaptability, and achieving a good balance between the filtration performance of the gradient nanofiber filter layer and system integration requirements.

[0008] In some embodiments, the pore size of the main channel filtration zone is 10 μm to 50 μm, the pore size of the particle interception zone is 1 μm to 10 μm, and the pore size of the deep deposition zone is 100 nm to 1 μm. This pore size gradient configuration allows large particles to be intercepted first in the main channel zone while maintaining low flow resistance, medium-sized particles to be captured in the interception zone, and submicron and nano-sized particles to be efficiently collected in the deep deposition zone through Brownian diffusion, electrostatic adsorption, and other processes. The synergistic effect of the multi-level gradient pore size achieves depth filtration across the entire particle size spectrum, significantly improving the capture efficiency of small wear particles and corrosion debris, and delaying the overall clogging process of the gradient nanofiber filter layer.

[0009] In some embodiments, the cross-section of the local guide channel is an arc-shaped, V-shaped, trapezoidal, or spiral shallow groove structure, and the swirling buffer is disposed at the end of the local guide channel and / or at the return dead zone. Limiting the cross-section of the local guide channel to an arc-shaped, V-shaped, trapezoidal, or spiral shallow groove structure, and placing the swirling buffer at the end of the guide channel and / or at the return dead zone, allows for the optimization of different channel cross-sectional shapes based on actual flow field characteristics to achieve efficient induction of particle inertial deflection. Placing the swirling buffer at the end of the local guide channel or in the return dead zone fully utilizes the low-speed return effect of the flow field structure, causing particles to decelerate, aggregate, and settle onto the fiber layer surface in this area, thereby further improving the particle capture probability and the effective utilization rate of the gradient nanofiber filter layer.

[0010] In some embodiments, the gradient nanofiber filter layer comprises a hydrophobic polymer framework material and an anti-corrosion functional component. The hydrophobic polymer framework material reduces moisture intrusion and swelling of the fiber layer, maintaining the mechanical stability of the fiber network structure and the hydrophobic environment; the anti-corrosion functional component actively inhibits or neutralizes corrosive media, endowing the gradient nanofiber filter layer with chemical protection capabilities for the valve body surface. Thus, the gradient nanofiber filter layer possesses both physical interception and chemical corrosion prevention functions, achieving a synergistic effect of filtration and corrosion prevention, overcoming the shortcomings of traditional single filtration or single corrosion prevention measures.

[0011] In some embodiments, the hydrophobic polymer backbone material is ethyl cellulose, and the anti-corrosion functional component is sodium lignosulfonate. Sodium lignosulfonate serves as the anti-corrosion functional component. Ethyl cellulose possesses good hydrophobicity, mechanical strength, and solution spinnability, enabling the formation of a stable multi-scale fiber backbone; sodium lignosulfonate contains polar sulfonic acid groups, which, while improving the conductivity of the spinning solution and promoting multi-peak splitting to form nanofibers under an electric field, also act as a green corrosion inhibitor to provide anti-corrosion protection for metal surfaces. The combination of these two components makes it easier to obtain a gradient fiber structure during the fiber layer preparation process and allows it to continuously exert both filtration and anti-corrosion effects during use.

[0012] This invention also provides a method for preparing a gradient nanofiber filter corrosion-resistant structure on the surface of a valve core and valve sleeve, comprising the following steps: Step S1: Dissolve the polymer framework material and functional molecules in a solvent to prepare a spinning solution; Step S2: The spinning solution is injected into the spinneret, and a high-voltage electric field is applied to perform electrohydrodynamic jet spinning to form gradient nanofibers co-deposited with micron-sized main fibers, submicron-sized transition fibers and nano-sized short fibers. Step S3: Fix the gradient nanofibers to a predetermined area on the surface of the valve core and / or valve sleeve by means of adhesion, hot pressing, or in-situ deposition to form a gradient nanofiber filter layer; Step S4: Local flow channels and swirling buffer zones are formed on the surface of the valve core and / or valve sleeve, adjacent to the gradient nanofiber filter layer. Through the process flow of steps S1 to S4, the aforementioned gradient nanofiber filter corrosion-resistant structure can be systematically manufactured. Step S2 utilizes electrohydrodynamic jet spinning technology to integrally form a gradient fiber assembly with micron-, submicron-, and nano-scale fibers co-deposited under a high-voltage electric field; the process is simple and the structure is controllable. Step S3 uses various methods such as adhesion, hot-pressing composite, or in-situ deposition to fix the fiber layer, adapting to complex surface shapes and ensuring a strong bond. Step S4 processes local flow channels and swirling buffer zones adjacent to the gradient nanofiber filter layer, ensuring spatial matching and functional synergy between the flow field control structure and the gradient nanofiber filter layer. This method has clear process steps and controllable operation, making it suitable for integrated manufacturing within the limited space inside a precision valve.

[0013] In some embodiments, the polymeric framework material is ethyl cellulose, the functional molecule is sodium lignosulfonate, and the solvent is a mixed solvent of DMAc and THF. This material system can obtain a spinning solution with suitable conductivity and moderate viscosity, and can easily achieve multi-level branching and refinement of the jet under a high-voltage electric field, which is beneficial for forming a gradient network structure in which multi-scale fibers coexist. The moderate evaporation rate of the mixed solvent helps to solidify and shape the fibers and improve the quality of the membrane layer, ensuring the structural uniformity and functional reliability of the final gradient nanofiber filter layer.

[0014] In some embodiments, in step S2, when a high-voltage electric field is applied, the electric field strength satisfies the electrocapillary number CaE > 1, where CaE = εE²r / γ, ε is the dielectric constant, E is the electric field strength, r is the characteristic radius of the jet, and γ is the surface tension. The electric field strength satisfies the electrocapillary number CaE > 1, CaE = εE²r / γ. When this condition is met, the electric field force is sufficient to overcome the surface tension constraint of the jet, causing the jet to transform from a single-jet mode to a multi-peak splitting and unstable bending refinement mode. This is a key process control condition for efficiently generating a large number of nanoscale short fibers and achieving fiber-scale gradients and progressively decreasing pore sizes. By quantitatively controlling the electric field parameters, the desired multi-scale gradient fiber structure can be stably reproduced, ensuring the consistency and excellent filtration performance of the gradient nanofiber filter layer product.

[0015] The beneficial effects of this invention are: First, through the integrated design of local guide channels, swirling buffer zones, and gradient nanofiber filter layers, a deep coupling between valve flow field regulation and particle filtration is achieved. The local guide channels alter the inertial migration path of particles, deflecting them towards the filtration area; the swirling buffer zones reduce particle velocity and extend their residence time on the surface of the gradient nanofiber filter layer; and the gradient fiber layer completes step-by-step interception and deep deposition. The synergistic effect of these three elements significantly improves particle capture efficiency and reduces the risk of local clogging.

[0016] Second, a gradient nanofiber network composed of micron-sized main fibers, submicron-sized transition fibers, and nano-sized short fibers was constructed. Through the spatial stacking of fibers of different scales, a step-by-step particle filtration mechanism is formed, which realizes the step-by-step interception and deep deposition of particles of different scales in the main channel area, particle interception area, and deep deposition area, significantly improving the capture efficiency of tiny wear particles and corrosion debris inside the precision valve.

[0017] Third, through the gradient pore size structure and deep filtration path design, particles migrate and are buffered and deposited in the fiber layer step by step, avoiding the problem of increased pressure drop and decreased flow rate caused by rapid accumulation of particles in local areas in traditional surface filtration mechanisms, thus improving the long-term stability and service life of the filtration structure.

[0018] Fourth, it can be directly integrated into the valve inlet area, reflux area and high wear area, achieving localized and precise protection without significantly increasing the system volume, and reducing the probability of particles entering the micro-gap area between the valve core and valve sleeve.

[0019] Fifth, by constructing a composite functional interface through hydrophobic skeleton materials and anti-corrosion functional components, the accumulation of moisture, acidic degradation products and oxidation byproducts in the valve core and valve sleeve area is reduced, thereby achieving synergistic effects of filtration and anti-corrosion. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0021] Figure 1 This is an internal structural diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the high dipole moment EHD multi-peak splitting process for forming nanofibers according to an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of the gradient nanofiber filter layer according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the multi-stage filtration and low-resistance flow mechanism in an embodiment of the present invention. Detailed Implementation

[0022] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings, are intended to cover non-exclusive inclusion.

[0024] The directional and positional terms used in this invention, such as up, down, front, back, left, right, inside, outside, top, bottom, side, etc., are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustrating and understanding this invention, and not for limiting the scope of protection of this invention.

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments: Example 1 like Figures 1 to 4 As shown, this embodiment of the invention provides a gradient nanofiber filtration and corrosion protection structure for the valve core and valve sleeve surface. The structure includes a valve body 10, a valve core 20, a valve sleeve 30, an inlet filtration area 40, a return buffer area 50, and a high-wear protection area 60. The gradient nanofiber filtration layer 100 is arranged in a ring-shaped manner near the valve inlet area, the valve core return area, and the high-wear area of ​​the valve sleeve, and is fixed to the inner wall surface of the valve body by adhesion.

[0026] The gradient nanofiber filter layer 100 has a thickness of 200 μm. Along the fluid flow direction, the gradient nanofiber filter layer sequentially forms a main channel filtration region 110, a particle interception region 120, and a deep deposition region 130. The pore size of the main channel filtration region 110 is 20 μm to 40 μm, the pore size of the particle interception region 120 is 3 μm to 8 μm, and the pore size of the deep deposition region 130 is 200 nm to 800 nm.

[0027] The valve core 20 has a local flow guide groove 200 on its surface. The local flow guide groove 200 has a V-shaped cross-section and is disposed adjacent to the gradient nanofiber filter layer 100. A swirling buffer zone 300 is disposed at the end of the local flow guide groove 200. The local flow guide groove 200 is used to change the local fluid velocity distribution and particle migration path, causing wear particles and metal debris to be deflected to the area where the gradient nanofiber filter layer 100 is located; the swirling buffer zone 300 is used to form a low-speed swirling flow field, prolonging the residence time of particles on the surface of the gradient nanofiber filter layer.

[0028] Example 2 This embodiment provides a method for preparing a gradient nanofiber filter and corrosion-resistant structure on the surface of a valve core and valve sleeve, specifically including the following steps: Step S1: Preparation of spinning solution: Ethyl cellulose is used as the polymer backbone material, and sodium lignosulfonate is used as the functional molecule. The ethyl cellulose is dissolved in a mixed solvent of DMAc and THF to prepare the spinning solution. The mass ratio of ethyl cellulose to sodium lignosulfonate is 10:1 to 5:1, and the total concentration of the solution is 8wt% to 15wt%.

[0029] Step S2, Electrohydrodynamic Jet Spinning: (e.g.) Figure 2As shown, the spinning solution is injected into the spinneret, and a high-voltage electric field is applied. Under the action of the strong electric field, a Taylor cone is formed at the end of the spinneret. Sodium lignosulfonate contains polar sulfonic acid groups, which can enhance the conductivity and interfacial polarization of the system, inducing multi-level bifurcation and local refinement of the jet in the electric field. When the electric field strength satisfies the electrocapillary number CaE > 1, the electric field force exceeds the interfacial tension constraint, and the jet changes from a single-jet mode to a multi-peak splitting mode, forming a large number of nanoscale short fiber structures. Figure 3 As shown, after electrohydrodynamic multi-peak splitting, a distinct multi-scale interlaced structure is formed inside the fiber layer. A large number of submicron-sized fine fibers 510 and local short nanofibers 520 are distributed between the coarser micron-sized main fibers 500. A non-uniform gradient pore network is formed between the fibers, thereby obtaining gradient nanofibers co-deposited with micron-sized main fibers, submicron-sized transition fibers and nanofibers.

[0030] Step S3: Fixing the gradient nanofiber filter layer: The formed gradient nanofibers are fixed on the surface of the valve core reflux area and the valve sleeve high wear area by in-situ deposition to form a gradient nanofiber filter layer 100.

[0031] Step S4: Processing the flow guiding and buffering structure: Local flow guiding grooves 200 and swirling buffers 300 are formed on the surface of the valve core and / or valve sleeve, adjacent to the gradient nanofiber filter layer 100.

[0032] Example 3 This embodiment tests the filtration performance of the gradient nanofiber filtration and corrosion-resistant structure of the present invention.

[0033] Ordinary metal microporous filter screen, single-scale electrospun nanofiber membrane and gradient nanofiber filter layer of the present invention were set as comparative samples, and their filtration performance was tested under the same flow rate, the same particle concentration and the same test time.

[0034] like Figure 4 As shown, this invention establishes a multi-stage particle capture mechanism based on inertial collision, Brownian diffusion, and electrostatic adsorption. The particle-containing fluid 600 flows axially along the valve core 20. Under the action of the local guide channel 200, larger particles 610 are deflected by inertia towards the gradient nanofiber filter layer 100. In the swirling buffer zone 300, the particle velocity decreases and the residence time increases. Subsequently, the particles sequentially pass through the main channel filtration zone 110, the particle interception zone 120, and the deep deposition zone 130, achieving staged interception. The purified fluid 620 passes through the low-resistance main channel.

[0035] During this process, the particle motion satisfies: in, For resistance, For Brownian diffusion force, It is electrostatic adsorption force. This is the term related to gravity. For particle mass, This represents the particle velocity.

[0036] The particle diffusion coefficient satisfies: in, Boltzmann's constant, For temperature, Particle size, This refers to the fluid dynamic viscosity.

[0037] The motion of fluid within the valve satisfies the Navier-Stokes equations: The motion of the fluid within the valve satisfies the incompressible Navier-Stokes equations: ρ( u / t + u· u) = - p + μ ²u + F Where ρ is the fluid density, u is the velocity vector, t is time, p is pressure, μ is the fluid dynamic viscosity, and F is the local guiding force. This guiding force F is generated by the geometric constraints and induction effects of the local guiding channel and swirling buffer on the flow field, and is used to characterize the regulation effect of the flow channel structure on the fluid velocity distribution and particle migration path.

[0038] The pressure drop characteristics of the gradient nanofiber filter layer described in this invention can be described using the Ergun equation: Where ΔP is the pressure drop, L is the thickness of the gradient nanofiber filter layer, μ is the hydrodynamic viscosity, and φ is the porosity. Let ρ be the fiber diameter, ρ be the fluid density, and u be the apparent velocity. From this equation, it can be seen that, for the same porosity, the fiber diameter... The smaller the fiber diameter, the greater the pressure drop; conversely, for the same fiber diameter, the higher the porosity φ, the lower the pressure drop. This invention employs a gradient fiber structure. The main channel region consists of coarser micron-sized fibers forming larger pores and higher porosity, allowing fluid to pass through with a lower pressure drop. In the particle interception zone and deep deposition zone, the fibers are progressively finer, with appropriately reduced porosity, enhancing interception capabilities. Compared to traditional single-scale dense filter layers, the gradient structure of this invention significantly improves effective permeability and reduces overall pressure drop, achieving efficient and low-resistance flow.

[0039] The permeation of the gradient nanofiber filter layer satisfies Darcy's law: in, For traffic, For penetration rate, For circulation area, For fluid viscosity, For pressure drop, The thickness of the gradient nanofiber filter layer is given.

[0040] Filtration efficiency is expressed as: in, and These represent the inlet and outlet particle concentrations, respectively.

[0041] To further comprehensively evaluate filtration performance, a filtration quality factor (QF) is introduced: in, For filtration efficiency, Pressure drop. A higher filtration quality factor (QF) indicates a higher filtration efficiency per unit pressure drop. This invention improves filtration efficiency η through a deep filtration mechanism with a gradient pore size structure, while simultaneously reducing pressure drop through a high-porosity main channel region. This significantly improves the filtration quality factor and achieves high-efficiency, low-resistance filtration.

[0042] Test results show that ordinary metal microporous filters have a filtration efficiency of approximately 65%–75% for submicron particles; single-scale nanofiber membranes have a filtration efficiency of 80%–88%, but the pressure drop increases significantly during operation; the gradient nanofiber filter layer 100 of this invention achieves a comprehensive filtration efficiency of over 90% for 0.3μm particles, while reducing the pressure drop by 20%–40% compared to single-scale nanofiber membranes. In dynamic filtration tests, the pressure drop rise rate of the filter structure of this invention is significantly lower than that of single-scale nanofiber membranes, indicating that its gradient pore structure can effectively delay local clogging.

[0043] Example 4 The difference between this embodiment and Embodiment 1 is that the gradient nanofiber filter layer 100 is fixed to the inner wall surface of the valve body inlet area by hot-pressing composite method, and the thickness of the gradient nanofiber filter layer 100 is 100μm. The pore size of the main channel filtration zone 110 is 10μm to 30μm, the pore size of the particle interception zone 120 is 1μm to 5μm, and the pore size of the deep deposition zone 130 is 100nm to 500nm. The cross-section of the local guide channel 200 is an arc-shaped structure.

[0044] Example 5 The difference between this embodiment and Embodiment 1 is that the gradient nanofiber filter layer 100 is fixed to the surface of the high-wear area of ​​the valve sleeve by in-situ deposition, and the thickness of the gradient nanofiber filter layer 100 is 400 μm. The pore size of the main channel filtration zone 110 is 30 μm to 50 μm, the pore size of the particle interception zone 120 is 5 μm to 10 μm, and the pore size of the deep deposition zone 130 is 500 nm to 1 μm. The cross-section of the local guide channel 200 is a spiral shallow groove structure, and the swirling buffer zone 300 is set at the end of the local guide channel 200 and at the return dead zone position.

[0045] Example 6 This embodiment tests the corrosion resistance of the gradient nanofiber filter structure of the present invention. Untreated bare steel specimens, a single ethyl cellulose fiber layer, and the gradient nanofiber filter layer containing sodium lignosulfonate of the present invention were used as comparative samples, and tests were conducted under the same corrosive medium and immersion time conditions.

[0046] The corrosion rate is calculated using the following formula: Where CR is the corrosion rate, K is a constant, ΔW is the mass loss, A is the corrosion area, t is the corrosion time, and ρ is the material density.

[0047] Test results show that the corrosion rate of the gradient nanofiber filter layer 100 containing anti-corrosion functional components of this invention is significantly lower than that of the bare steel sample, and further lower than that of the single ethyl cellulose fiber layer. By forming a hydrophobic protective layer through ethyl cellulose and constructing an anti-corrosion interface in combination with functional components such as sodium lignosulfonate, the accumulation of moisture, acidic degradation products, and oxidation byproducts in the valve core and valve sleeve mating area can be effectively reduced, achieving synergy between filtration and anti-corrosion functions, and significantly improving the long-term reliability and corrosion stability of the precision valve.

[0048] The gradient nanofiber filtration and corrosion protection structure on the valve core and valve sleeve surface of the present invention and its preparation method can be widely used in precision fluid control equipment such as hydraulic valves, servo valves and pneumatic valves. It is particularly suitable for high-end hydraulic systems and precision fluid equipment with high requirements for filtration accuracy, operational stability and corrosion resistance, and has good industrial applicability.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this invention; the scope of protection of this invention is defined by the claims in the claims, and all equivalent changes and modifications made in accordance with this invention are within the scope of protection of this patent.

Claims

1. A gradient nanofiber filtration and corrosion-resistant structure on the surface of a valve core and valve sleeve, characterized in that: include: Gradient nanofiber filter layer disposed on the surface of valve core and / or valve sleeve; And local flow channels and swirling buffers disposed on the surface of the valve core and / or valve sleeve, adjacent to the gradient nanofiber filter layer; The gradient nanofiber filter layer is composed of a multi-scale gradient pore network consisting of micron-scale main fibers, submicron-scale transition fibers, and nano-scale short fibers. Along the fluid flow direction, the average pore size of the gradient nanofiber filter layer decreases step by step, forming the main channel filtration zone, the particle interception zone and the deep deposition zone in sequence. The local flow channel is configured to change the local fluid velocity distribution and particle migration path, so as to deflect the particles to the gradient nanofiber filter layer; the swirling buffer is configured to form a low-speed swirling flow field to prolong the residence time of the particles on the surface of the gradient nanofiber filter layer.

2. The gradient nanofiber filtration and corrosion-resistant structure on the surface of the valve core and valve sleeve according to claim 1, characterized in that: The gradient nanofiber filter layer is disposed in the valve inlet region, the valve core reflux region, and / or the valve sleeve high wear region.

3. The gradient nanofiber filtration and corrosion-resistant structure on the surface of the valve core and valve sleeve according to claim 1, characterized in that: The thickness of the gradient nanofiber filter layer is 50 μm to 500 μm.

4. The gradient nanofiber filtration and corrosion protection structure on the surface of the valve core and valve sleeve according to claim 1, characterized in that: The pore size of the main channel filtration zone is 10μm to 50μm, the pore size of the particle interception zone is 1μm to 10μm, and the pore size of the deep deposition zone is 100nm to 1μm.

5. The gradient nanofiber filtration and corrosion protection structure on the surface of the valve core and valve sleeve according to claim 1, characterized in that: The cross-section of the local guide channel is an arc-shaped, V-shaped, trapezoidal, or spiral shallow groove structure, and the swirling buffer zone is set at the end of the local guide channel and / or the return dead zone position.

6. The gradient nanofiber filtration and corrosion protection structure on the surface of the valve core and valve sleeve according to claim 1, characterized in that: The gradient nanofiber filter layer contains a hydrophobic polymer framework material and anti-corrosion functional components.

7. The gradient nanofiber filtration and corrosion protection structure on the surface of the valve core and valve sleeve according to claim 6, characterized in that: The hydrophobic polymer framework material is ethyl cellulose, and the preservative functional component is sodium lignosulfonate.

8. A method for preparing a gradient nanofiber filter corrosion-resistant structure on the surface of a valve core and valve sleeve as described in any one of claims 1 to 7, characterized in that: Includes the following steps: Step S1: Dissolve the polymer framework material and functional molecules in a solvent to prepare a spinning solution; Step S2: The spinning solution is injected into the spinneret, and a high-voltage electric field is applied to perform electrohydrodynamic jet spinning to form gradient nanofibers co-deposited with micron-sized main fibers, submicron-sized transition fibers and nano-sized short fibers. Step S3: Fix the gradient nanofibers to a predetermined area on the surface of the valve core and / or valve sleeve by means of adhesion, hot pressing, or in-situ deposition to form a gradient nanofiber filter layer; Step S4: Local guide grooves and swirling buffer zones are formed on the surface of the valve core and / or valve sleeve, adjacent to the gradient nanofiber filter layer.

9. The method for preparing the gradient nanofiber filter corrosion-resistant structure on the surface of the valve core and valve sleeve according to claim 8, characterized in that: The polymeric framework material is ethyl cellulose, the functional molecule is sodium lignosulfonate, and the solvent is a mixture of DMAc and THF.

10. The method for preparing the gradient nanofiber filter corrosion-resistant structure on the surface of the valve core and valve sleeve according to claim 8, characterized in that: In step S2, when a high-voltage electric field is applied, the electric field strength satisfies the electrocapillary number CaE > 1, where CaE = εE²r / γ, ε is the dielectric constant, E is the electric field strength, r is the characteristic radius of the jet, and γ is the surface tension.

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