Ball body for ceramic ball valve, preparation method of ball body, valve element assembly and ball valve

Abstract

The invention provides a ball body for a ceramic ball valve, a preparation method of the ball body, a valve element assembly and the ball valve, and relates to the technical field of ceramic ball valves. The ball body for the ceramic ball valve is integrally formed by a zirconia-based ceramic material through a 3D printing technology, a valve rod groove is formed in one top end of the ball body, a ball body runner hole is formed in the middle of the ball body, and a micron-sized pit array is arranged on the spherical surface of the ball body; the matrix part of the sphere and the micron-sized pit array are of an integral structure which is continuous in material and free of a bonding interface; the micron-sized pit arrays are distributed on the surface of the ball body in a functionally graded mode, namely, the distribution density of the micron-sized pit arrays in a main sealing ring belt area of the ball body is higher than that of the micron-sized pit arrays in an end area of the ball body, and the size of the micron-sized pits in the main sealing ring belt area is smaller than that of the micron-sized pits in the end area. The ball body for the ceramic ball valve not only overcomes the damage to the ball body caused by later processing, but also has the advantages of excellent corrosion resistance, wear resistance, lubricity and reliability.

Description

Technical Field

[0001] This invention relates to the field of ceramic ball valve technology, specifically to a ball for a ceramic ball valve, its preparation method, valve core assembly, and ball valve. Background Technology

[0002] Ball valves, as an important fluid control component, are widely used in industrial production. However, under harsh conditions such as deep-sea drilling and chemical transportation, characterized by high pressure, high corrosion, and low friction torque, traditional metal ball valves are prone to corrosion, wear, and adhesion, leading to frequent replacements and eventual scrapping. To address this issue, ceramic ball valves, with their high strength, high hardness, low density, and excellent wear resistance, corrosion resistance, and high-temperature resistance, have gradually gained application in recent years. The core components of a ceramic ball valve include the valve body, valve core assembly, and valve stem. The valve core assembly is located within the valve body and includes a ball and a valve seat. The ball is installed within the valve seat and has a valve stem groove and flow channel hole. By rotating the valve stem above the spherical ball, the entire ceramic ball valve can be opened or closed.

[0003] However, ceramic ball valves used in the extreme conditions of deep-sea drilling generally face two major technical challenges. First, the H2S dissolved in deep-sea crude oil can cause severe corrosion to key valve components (such as the ball and seat), leading to surface failure and reduced sealing performance. Second, during valve opening and closing, the contact interface between the ball and the seat must withstand friction under high pressure. If lubrication is insufficient, high frictional torque can easily be generated, making it difficult to open and close the valve. In extreme cases, the friction interface may "seize up" due to metal adhesion or the accumulation of ceramic wear debris, preventing the valve from opening or closing normally, directly interrupting drilling operations and causing huge economic losses.

[0004] To address the aforementioned corrosion and lubrication issues, existing technologies primarily employ two types of surface treatment methods. One method involves machining micron-sized pits and other lubrication structures onto the surface of a traditional sintered ceramic ball valve, followed by spraying or plating. However, this is a post-processing method, resulting in a distinct interface between the surface layer and the substrate, leading to weak adhesion and susceptibility to peeling under high-pressure cyclic loading. Furthermore, the machining process itself introduces stress concentration points, affecting the overall strength of the ball. The other method involves laser etching micron-sized pits onto the surface of the ceramic ball valve. While this technique can achieve a specific oil storage structure, it is essentially a subtractive manufacturing process. High-energy laser beams inevitably cause subsurface damage such as microcracks and phase transformations when processing dense zirconia ceramics. Additionally, the resulting pits typically have sharp edges, becoming potential stress concentration sources and significantly reducing the fatigue life of the ball valve.

[0005] Therefore, there is an urgent need in this field to develop a ceramic ball valve that is corrosion-resistant, wear-resistant, and has long-lasting lubrication performance and high operational reliability, as well as its preparation method. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a ball for a ceramic ball valve, its preparation method, a valve core assembly, and a ball valve. The ball for the ceramic ball valve not only overcomes the damage to the ball caused by subsequent processing, but also gives it excellent corrosion resistance, wear resistance, lubricity, and reliability.

[0007] The specific technical solution of this invention is as follows: In a first aspect, the present invention provides a ball for a ceramic ball valve, the ball being integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is provided on the surface of the ball. The base part of the ball and the micron-level pit array are integral structures with continuous material and no bonding interface. The micron-level pit array is functionally gradient distributed on the surface of the ball, that is, the distribution density of the micron-level pit array in the main sealing ring area of ​​the ball is higher than that in the end area, and the size of the micron-level pits in the main sealing ring area is smaller than that in the end area.

[0008] In one possible implementation, the shape of the micron-sized pit is one or more of the following: circular, elliptical, teardrop-shaped, fish-scale-shaped, honeycomb-shaped, and having a parabolic profile.

[0009] In one possible implementation, in the main sealing ring area, the coverage area of ​​the micron-sized pits accounts for 40%-50% of the area of ​​the main sealing ring area, and the maximum size of the micron-sized pits is 20-30 μm; in the end area, the coverage area of ​​the micron-sized pits accounts for 20%-30% of the area of ​​the end area, and the maximum size of the micron-sized pits is 40-50 μm.

[0010] In one possible implementation, at the opening edge of the micron-sized pit, the boundary region of the spherical surface of the sphere that is recessed downwards is a smooth rounded corner structure with a radius of 3-8 μm.

[0011] In one possible embodiment, the zirconium oxide-based ceramic material comprises the following molar amounts of raw materials: 100 parts ZrO2, 2-4 parts Y2O3, 2-4 parts CeO2, 4-12 parts Al2O3, and 0.2-2 parts TiO2.

[0012] Secondly, the present invention provides a method for preparing the ball for the above-mentioned ceramic ball valve, comprising the following steps: S1. Three-dimensional modeling: Establish a three-dimensional digital model of the sphere, and pre-enlarge the three-dimensional digital model according to the shrinkage rate of the zirconia-based ceramic material to obtain the sphere model; S2. Additive manufacturing: Based on the spherical model described in step S1, zirconia-based ceramic slurry is 3D printed into a spherical green body; S3. Hot degreasing and sintering: The spherical green body described in step S2 is cleaned, hot degreased and sintered to obtain a sphere with an integrally formed micron-level pit array.

[0013] In one possible implementation, the 3D printing in step S2 employs digital light processing technology or stereolithography.

[0014] In one possible implementation, the thermal degreasing in step S3 is carried out in an air atmosphere, with a heating rate of 5-10 ℃ / h, a holding temperature of 500-600 ℃, and a time of 1-4 h.

[0015] In one possible implementation, the sintering temperature in step S3 is 1500-1600 °C, the atmosphere is air, and the time is 1-4 h.

[0016] Thirdly, the present invention provides a valve core assembly, including the aforementioned ball and a valve seat that cooperates therewith. An elastic element is provided on the back side of the valve seat away from the sealing surface of the ball. The elastic element is used to apply pressure toward the ball to the valve seat to form an initial seal and to automatically adjust the pressure on the valve seat through its own elastic expansion and contraction to achieve dynamic compensation of the sealing effect.

[0017] In one possible implementation, the elastic element is a disc spring.

[0018] Fourthly, the present invention provides a ball valve that uses the ball of the above-mentioned ceramic ball valve. This invention provides a ceramic ball valve ball that is integrally formed using additive manufacturing technology. This achieves damage-free and interface-free manufacturing of the ceramic ball and its surface microtexture, fundamentally eliminating microcracks and stress concentration sources, and significantly improving fatigue strength and reliability. Based on a functional gradient design, a micron-level pit array is used in the main sealing ring area with a high-density, small-size distribution to balance lubrication and load-bearing, while a low-density, large-size layout is used in the end area to enhance oil storage capacity. This synergistically induces a hydrodynamic effect, reducing the coefficient of friction to 0.02-0.05 and effectively preventing high-pressure "seizure". Combined with zirconia ceramic material, the ball possesses high strength, high toughness, high hardness, and corrosion resistance. Attached Figure Description

[0019] Figure 1 This is a three-dimensional view of the sphere in Example 1.

[0020] Figure 2 This is an enlarged schematic diagram of the teardrop-shaped micron-sized pit in Example 1.

[0021] Figure 3 This is an enlarged schematic diagram of the circular micron-scale pit array in Example 1.

[0022] Figure 4 This is a perspective view of the valve core assembly in Example 7.

[0023] Figure 5 The flowchart shows the sphere preparation methods in Examples 1-6.

[0024] Figure Labels 1-Spherical body, 2-Valve seat, 3-Disc spring, 11-Spherical flow channel hole, 12-Micron-level pit array, 13-Valve stem groove, 14-Main sealing ring area, 15-End area, 121-Teardrop-shaped micron-level pit, 122-Circular micron-level pit, 123-Rounded corner structure, 21-Valve seat flow channel hole. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the present invention.

[0026] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0028] Terminology Explanation: Main sealing ring area: In this invention, it refers to the annular strip area on the surface of the ball that contacts the valve seat and performs the main sealing function when the ceramic ball valve is in the closed state.

[0029] End region: In this invention, it refers to the portion on the spherical surface of the sphere that is located on both sides of the main sealing ring area and adjacent to the axis of rotation of the sphere.

[0030] The specific technical solution of this invention is as follows: In a first aspect, the present invention provides a ball for a ceramic ball valve, the ball being integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is provided on the surface of the ball. The base part of the ball and the micron-level pit array are integral structures with continuous material and no bonding interface. The micron-level pit array is functionally gradient distributed on the surface of the ball, that is, the distribution density of the micron-level pit array in the main sealing ring area of ​​the ball is higher than that in the end area, and the size of the micron-level pits in the main sealing ring area is smaller than that in the end area.

[0031] This invention provides a ceramic ball valve sphere that, through the synergistic effect of three core technological features—3D printing integrated molding, continuous interface-free material structure, and functional gradient distribution of a micron-level pit array—overcomes post-processing damage while simultaneously ensuring excellent corrosion resistance, wear resistance, lubricity, and reliability. Zirconia-based ceramics inherently possess excellent chemical stability, exhibiting strong resistance to acid, alkali, and salt media in environments such as nuclear power plants and chemical plants. This prevents sealing performance degradation due to corrosion failure of the sealing surface, establishing the sphere's corrosion resistance advantage at the material level. 3D printing technology integrally molds the sphere matrix, valve stem groove, flow channel holes, and micron-level pit array, completely eliminating stress concentration points and subsurface damage introduced by subsequent machining or laser etching. This ensures the integrity of the sphere matrix structure, avoiding weakening of the ceramic material's strength due to processing damage and preventing damaged areas from becoming weak points for corrosive media intrusion, further enhancing the sphere's corrosion resistance and structural reliability. The micron-level pit array and the sphere matrix are made of the same zirconia-based ceramic material and are continuous and interface-free, eliminating the problem of insufficient bonding strength. Under conditions of long-term friction and high pressure between the ball and valve seat, the micron-sized pit array will not detach due to interface separation, ensuring the long-term stability of the structure and providing continuous support for wear resistance and lubrication. Zirconia-based ceramics inherently possess high hardness and high fracture toughness, while the interface-free micron-sized pit array structure does not disrupt the continuity of its matrix. This allows the ball surface to retain the wear-resistant foundation of the ceramic material while simultaneously optimizing and dispersing frictional stress through microstructural optimization. The main sealing ring area is the core contact area between the ball and valve seat, bearing the main sealing pressure and friction. High-density (high coverage), small-sized micron-sized pits are designed in this area. High-density pits can store more lubricant, forming a continuous and stable oil film at the friction interface, reducing the coefficient of friction and minimizing severe wear caused by dry friction. Simultaneously, the small-sized pits cause minimal damage to the integrity of the ball surface, ensuring lubrication while maintaining sufficient bearing area, further enhancing wear resistance and deformation resistance. The non-core sealing contact area at the end employs a low-density design to avoid excessive pits that could weaken the structural strength of the ball's end. Simultaneously, the large pits act as lubricant reservoirs, replenishing lubricant to the main sealing ring area through ball rotation, thus extending the overall lubrication cycle. This gradient distribution precisely matches the failure risks of different areas, achieving an optimal balance between lubricity, wear resistance, and corrosion resistance, ultimately ensuring long-term reliability.

[0032] In one possible implementation, the micron-sized pits are one or more of the following shapes: circular, elliptical, teardrop-shaped, fish-scale-shaped, honeycomb-shaped, and having a parabolic profile. A circular shape is the most perfectly isotropic geometry, with the most uniform stress distribution and no obvious directional weaknesses during processing and under stress. As a basic and reliable oil reservoir, it can provide stable and predictable lubrication. Elliptical and teardrop shapes are directional, guiding the flow of lubricating oil from low-pressure areas to high-pressure areas, greatly enhancing the hydrodynamic lubrication effect and making them suitable for operating conditions with higher lubrication requirements. Fish-scale shapes are biomimetic structures; their unique asymmetrical geometry can guide tiny wear particles generated in the friction pair into the pits or out of the sealing area, effectively reducing wear. Honeycomb shapes are also biomimetic structures; their hexagonal boundary connections create a continuous, high-strength support network between the pits, allowing for a high-density texture while maintaining the maximum effective load-bearing area.

[0033] In one possible implementation, in the main sealing ring area, the coverage area of ​​the micron-sized pits accounts for 40%-50% of the area of ​​the main sealing ring area, and the maximum size of the micron-sized pits is 20-30 μm; in the end area, the coverage area of ​​the micron-sized pits accounts for 20%-30% of the area of ​​the end area, and the maximum size of the micron-sized pits is 40-50 μm. The high pit coverage of 40%-50% in the main sealing ring area can form a dense "micro-oil pool" within a limited contact area, efficiently storing lubricant and quickly forming a continuous oil film during relative movement of the sealing surfaces, significantly reducing the coefficient of friction. Simultaneously, the small-sized pits of 20-30 μm cause minimal damage to the integrity of the sealing surface substrate, ensuring lubrication while maintaining sufficient bearing area; the low pit coverage of 20%-30% in the end area reduces the weakening of the sealing surface structural strength by the pits; and the large-sized pits of 40-50 μm act as lubricant reservoirs, replenishing lubricant to the main sealing ring area through spherical rotation, extending the overall lubrication cycle.

[0034] In one possible implementation, at the opening edge of the micron-sized pit, the boundary region of the spherical surface of the sphere that is recessed downwards is a smooth rounded corner structure with a radius of 3-8 μm. Using a rounded corner structure with a radius of 3-8 μm at the opening edge of the micron-sized pit serves two purposes: firstly, it disperses stress through an arc transition, avoiding stress concentration; secondly, the smooth transition of the rounded edge facilitates the introduction of lubricant to the contact surface, reducing damage to the lubricant film and ensuring that the lubricant stored in the pit can continuously form a complete oil film at the contact interface, thus reducing the coefficient of friction.

[0035] In one possible implementation, the zirconia-based ceramic material comprises the following molar amounts of raw materials: 100 parts ZrO2, 2-4 parts Y2O3, 2-4 parts CeO2, 4-12 parts Al2O3, and 0.2-2 parts TiO2. Y₂O₃ (yttrium oxide) and CeO₂ (cerium oxide) are both highly efficient tetragonal phase stabilizers for zirconia. The addition of these two in the above-mentioned proportions can form a more uniform and stable stress field within the zirconia grains, synergistically suppressing the transformation of the tetragonal phase to the monoclinic phase at high temperatures, ensuring that the material maintains a tetragonal-dominated core structure after sintering and during long-term service. 4-12 parts of Al₂O₃ (aluminum oxide) can, on the one hand, inhibit abnormal growth of zirconia grains during sintering, playing a role in grain refinement and strengthening; on the other hand, the dispersed Al₂O₃ particles, as a second phase, can pin grain boundaries and hinder dislocation movement, which is beneficial to improving the bending strength and hardness of the material. 0.2-2 parts of TiO₂ can form a eutectic during sintering, significantly promoting the diffusion and mass transfer processes, helping to eliminate residual pores inside the material, and enabling the ceramic spheres to achieve extremely high density. High density is a prerequisite for obtaining high reliability, high strength, and excellent corrosion resistance.

[0036] Secondly, the present invention provides a method for preparing the ball for the above-mentioned ceramic ball valve, comprising the following steps: S1. Three-dimensional modeling: Establish a three-dimensional digital model of the sphere, and pre-enlarge the three-dimensional digital model according to the shrinkage rate of the zirconia-based ceramic material to obtain the sphere model; S2. Additive manufacturing: Based on the spherical model described in step S1, zirconia-based ceramic slurry is 3D printed into a spherical green body; S3. Hot degreasing and sintering: The spherical green body described in step S2 is cleaned, hot degreased and sintered to obtain a sphere with an integrally formed micron-level pit array.

[0037] The method for preparing ceramic ball valve spheres provided by this invention constructs a complete and efficient integrated manufacturing system through a technical path of "digital design—additive manufacturing—densification sintering". Through 3D modeling, any complex biomimetic microtexture and its functional gradient distribution can be precisely designed in the digital model. Subsequently, the additive manufacturing process effectively transforms the digital model into a physical green body. Simultaneous printing of the sphere matrix and micro-dimple array not only avoids the problems of microcracks, heat-affected zones, residual stress, and sharp edges caused by the traditional subtractive manufacturing process of "making the green body first, then processing the texture," but also shortens the production cycle and reduces manufacturing costs. Furthermore, because the entire manufacturing process is driven by the same digital model, and the additive manufacturing process itself has a high degree of automation, the macroscopic structure and microtexture of each batch of spheres produced have extremely high consistency and repeatability. This is particularly suitable for scenarios with stringent requirements for product performance consistency, laying the foundation for large-scale, standardized production.

[0038] In one possible implementation, the 3D printing in step S2 employs digital light processing (DLP) or stereolithography (SLA). DLP and SLA are among the additive manufacturing technologies currently available with the highest resolution and best precision. DLP achieves surface exposure through digital micromirror devices, while SLA performs point scanning using a focused laser beam. Both achieve micrometer-level positioning accuracy and minimum feature size, ensuring that the micrometer-level pit array designed in step S1 can be printed onto the spherical green body with high fidelity and clarity.

[0039] In one possible implementation, the thermal degreasing in step S3 is carried out in an air atmosphere, with a heating rate of 5-10 °C / h, a holding temperature of 500-600 °C, and a time of 1-4 h. The core task of thermal degreasing is to remove the organic binder from the ceramic slurry used for 3D printing in step S2. The heating rate of 5-10 °C / h allows sufficient time for the organic binder to decompose and diffuse out slowly from the surface inwards. Oxygen in the air can react with the organic matter to oxidize it, efficiently and thoroughly decomposing it into small molecule gases such as carbon dioxide and water vapor. Holding at 500-600 °C for 1-4 h ensures that most of the organic matter, especially those polymer chains that were not completely decomposed during the slow heating process, is fully and thoroughly removed.

[0040] In one possible implementation, the sintering temperature in step S3 is 1500-1600 °C, the atmosphere is air, and the time is 1-4 h. The sintering densification temperature of zirconia-based ceramics is usually between 1450-1650 °C, with 1500-1600 °C being the optimal range. This ensures that ceramic particles diffuse and fuse sufficiently, filling the tiny gaps in the green body and increasing the density of the spheres. The sintering time of 1-4 h allows the ceramic green body to fully complete particle diffusion and grain boundary migration at 1500-1600 °C, resulting in uniform density in all regions of the spheres.

[0041] Thirdly, the present invention provides a valve core assembly, including the aforementioned ball and a valve seat that cooperates therewith. An elastic element is provided on the back side of the valve seat away from the sealing surface of the ball. The elastic element is used to apply pressure toward the ball to the valve seat to form an initial seal and to automatically adjust the pressure on the valve seat through its own elastic expansion and contraction to achieve dynamic compensation of the sealing effect.

[0042] In one possible implementation, the elastic element is a disc spring. Disc springs have a conical disc structure and exhibit small deformation and large elastic force, providing stable and precise sealing pressure with relatively small compression.

[0043] Fourthly, the present invention provides a ball valve that uses the ball of the above-mentioned ceramic ball valve.

[0044] The technical solution of the present invention will be further described below with reference to specific embodiments and comparative examples. All reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing. The instruments used in the embodiments are also commercially available.

[0045] Example 1 This embodiment provides a ball 1 for a ceramic ball valve, such as... Figures 1-3 As shown, the sphere is integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove 13 is formed at one top of the sphere, and a flow channel hole 11 is provided in the middle of the sphere. A micron-level pit array 12 is formed on the surface of the sphere. The base of the sphere and the micron-level pit array 12 form a continuous material structure without a bonding interface. In the main sealing ring region 14 of the sphere, the micron-level pits are teardrop-shaped. The teardrop-shaped micron-level pits 121 have an aspect ratio of 3:1, a head curvature radius of 10 μm, a tail angle of 18° (total length 60 μm, maximum width 20 μm), and a depth of 8 μm. The teardrop-shaped micron-sized pits 121 have their central axes perpendicular to the rotation axis of the sphere, and are arranged in pairs, with the teardrop-shaped micron-sized pits 121 covering 45% of the area. At the end region 15 of the sphere, the micron-sized pits are circular, with the circular micron-sized pits 122 covering 25% of the area. The circular micron-sized pits 122 have a diameter of 45 μm and a depth of 12 μm. At the opening edges of the teardrop-shaped micron-sized pits 121 and the circular micron-sized pits 122, the boundary region where the spherical surface of the sphere 1 is concave downwards is a smooth rounded corner structure 123 with a radius of 5 μm.

[0046] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 3 mol Y2O3, 3 mol CeO2, 8 mol Al2O3, and 1 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder with an average particle size of 200 nm. Then, mix the nano-zirconia-based powder, sintering aid, photosensitive resin, and dispersant to prepare the ceramic slurry. The sintering aid is magnesium oxide, the photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator, with a dispersion grade of BYK-111. The content of nano-zirconia-based powder in the ceramic slurry is 50 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 40 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to an 18% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using a DLP printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and heated to 600 ℃ for 1 h at a heating rate of 8 ℃ / h. Then, it is heated to 1550 ℃ for sintering for 2 h to obtain a sphere for ceramic ball valve.

[0047] Example 2 This embodiment provides a ball for a ceramic ball valve, which is integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is provided on the surface of the ball. The base of the ball and the micron-level pit array are a continuous material structure without a bonding interface. The micron-level pits are circular in shape and arranged in a hexagonal array. In the main sealing ring area of ​​the ball, the coverage area of ​​the micron-level pits accounts for 40%, with a diameter of 20 μm and a depth of 5 μm. In the end area of ​​the ball, the coverage area of ​​the micron-level pits accounts for 20%, with a diameter of 40 μm and a depth of 8 μm. At the opening edge of the micron-level pits, the downward-recessed boundary area of ​​the spherical surface of the ball has a smooth rounded corner structure with a radius of 3 μm.

[0048] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 2 mol Y2O3, 2 mol CeO2, 4 mol Al2O3, and 0.2 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder with an average particle size of 200 nm. Then, mix the nano-zirconia-based powder, sintering aid, photosensitive resin, and dispersant to prepare the ceramic slurry. The sintering aid is magnesium oxide. The photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator. The dispersion grade is BYK-110. The content of nano-zirconia-based powder in the ceramic slurry is 45 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 45 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to a 15% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using a DLP printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and heated to 500 ℃ at a heating rate of 5℃ / h for degreasing for 4 h. Then, it is heated to 1500 ℃ for sintering for 4 h to obtain a sphere for ceramic ball valve.

[0049] Example 3 This embodiment provides a ball for a ceramic ball valve, integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is formed on the surface of the ball. The base of the ball and the micron-level pit array are a continuous material structure without a bonding interface. In the main sealing ring area of ​​the ball, the micron-level pits are elliptical in shape, with a major axis of 30 μm, a minor axis of 20 μm, and a depth of 8 μm. The major axis of the micron-level pits is perpendicular to the rotation axis of the ball and they are arranged in an array, covering 50% of the area. In the end area of ​​the ball, the micron-level pits are elliptical in shape and arranged in a rectangular array, covering 30% of the area. The major axis of the micron-level pits is 60 μm, the minor axis is 40 μm, and the depth is 15 μm. μm; At the opening edge of the micron-level pit, the boundary region of the spherical surface of the sphere that is concave downwards is a smooth rounded corner structure with a radius of 8 μm.

[0050] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 4 mol Y2O3, 4 mol CeO2, 12 mol Al2O3, and 2 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder with an average particle size of 200 nm. Then, mix the nano-zirconia-based powder, sintering aid, photosensitive resin, and dispersant to prepare the ceramic slurry. The sintering aid is magnesium oxide, and the photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator, with a dispersion grade of BYK-180. The content of nano-zirconia-based powder in the ceramic slurry is 55 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 35 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to a 20% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using a DLP printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and heated to 600 ℃ for 1 h at a heating rate of 10 ℃ / h. Then, it is heated to 1600 ℃ and sintered for 4 h to obtain a sphere for ceramic ball valve.

[0051] Example 4 This embodiment provides a ball for a ceramic ball valve, integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-sized pit array is formed on the surface of the ball. The base of the ball and the micron-sized pit array are a continuous material structure without a bonding interface. In the main sealing ring area of ​​the ball, the micron-sized pits are fish-scale shaped, covering 42% of the area. The leading edge of the fish-scale micron-sized pits is a convex arc with a radius of 12 μm, the trailing edge is a concave arc with a radius of 25 μm, and the side edges are convex arcs with a radius of 30 μm, with a depth of 9 μm. The central axis of the fish-scale micron-sized pits is perpendicular to the rotation axis of the ball, and the leading and trailing edges are arranged alternately. In the end area of ​​the ball, the micron-sized pits are circular in shape, arranged in a hexagonal array, covering 22% of the area. The diameter of the micron-sized pits is 42 μm and the depth is 10 μm. μm; At the opening edge of the micron-level pit, the boundary region of the spherical surface of the sphere that is concave downwards is a smooth rounded corner structure with a radius of 4 μm.

[0052] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 2.5 mol Y2O3, 2.5 mol CeO2, 6 mol Al2O3, and 0.5 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder raw material with an average particle size of 200 nm. Then mix the nano-zirconia-based powder raw material, sintering aid, photosensitive resin, and dispersant to prepare ceramic slurry. The sintering aid is magnesium oxide. The photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator. The dispersion grade is BYK-184. The content of nano-zirconia-based powder in the ceramic slurry is 48 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 42 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to a 15% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using a DLP printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and heated to 550 °C at a heating rate of 6 °C / h for degreasing for 2 h. Then, it is heated to 1520 °C for sintering for 3 h to obtain a sphere for ceramic ball valve.

[0053] Example 5 This embodiment provides a ball for a ceramic ball valve, which is integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is formed on the surface of the ball. The base of the ball and the micron-level pit array are a continuous material structure without a bonding interface. In the main sealing ring area of ​​the ball, the micron-level pits are circular in shape and arranged in a hexagonal array, covering 48% of the area. The diameter of the micron-level pits is 25 μm and the depth is 7 μm. In the end area of ​​the ball, the micron-level pits are honeycomb-shaped, covering 50% of the area. The diameter of the micron-level pits is 45 μm and the depth is 13 μm. At the opening edge of the micron-level pits, the downward-recessed boundary area of ​​the spherical surface of the ball has a smooth rounded corner structure with a radius of 6 μm.

[0054] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 3.5 mol Y2O3, 3.5 mol CeO2, 10 mol Al2O3, and 1.5 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder with an average particle size of 200 nm. Then, mix the nano-zirconia-based powder, sintering aid, photosensitive resin, and dispersant to prepare the ceramic slurry. The sintering aid is magnesium oxide. The photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator. The dispersion grade is BYK-111. The content of nano-zirconia-based powder in the ceramic slurry is 52 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 38 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to a 13% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using an SLA printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and degreased at 580 ℃ for 3 hours at a heating rate of 9 ℃ / h. Then, it is sintered at 1580 ℃ for 2 hours to obtain a sphere for ceramic ball valve.

[0055] Example 6 This embodiment provides a ball for a ceramic ball valve, which is integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove is formed at one top of the ball, and a flow channel hole is provided in the middle of the ball. A micron-level pit array is formed on the surface of the ball. The base of the ball and the micron-level pit array are a continuous material structure without a bonding interface. The micron-level pits are arranged in a hexagonal array. In the main sealing ring area of ​​the ball, the micron-level pits are elliptical in shape, covering 43% of the area. The major axis of the micron-level pits is 30 μm, the minor axis is 20 μm, and the depth is 8 μm. In the end area of ​​the ball, the micron-level pits are circular in shape, covering 24% of the area. The diameter of the micron-level pits is 48 μm, and the depth is 14 μm. At the opening edge of the micron-level pits, the downward-recessed boundary area of ​​the spherical surface of the ball has a smooth rounded corner structure with a radius of 5 μm.

[0056] The method for preparing the sphere provided in this embodiment includes the following steps: S0. Preparation of ceramic slurry: Weigh the raw materials according to the following molar ratios: 100 mol ZrO2, 2 mol Y2O3, 4 mol CeO2, 10 mol Al2O3, and 1.5 mol TiO2. Grind and mix them evenly to obtain nano-zirconia-based powder with an average particle size of 200 nm. Then, mix the nano-zirconia-based powder, sintering aid, photosensitive resin, and dispersant to prepare the ceramic slurry. The sintering aid is magnesium oxide. The photosensitive resin contains epoxy acrylate oligomer, a mixed diluent of propylene oxide neopentyl glycol diacrylate and tripropylene glycol diacrylate, and TPO-L photoinitiator. The dispersion grade is BYK-111. The content of nano-zirconia-based powder in the ceramic slurry is 46 vol%, the content of sintering aid is 5 vol%, the content of photosensitive resin is 44 vol%, and the content of dispersant is 5 vol%. S1. 3D Modeling: Establish a 3D digital model of the sphere in this embodiment, and enlarge the model according to a 20% shrinkage rate; S2. Additive manufacturing: Based on the three-dimensional digital model established in step S1, the ceramic slurry from step S0 is printed into spherical green bodies using an SLA printer. S3. Hot degreasing and sintering: After ultrasonic cleaning, the spherical green body obtained in step S2 is placed in an air furnace and heated to 520 °C at a heating rate of 7 °C / h for degreasing for 3 hours. Then, it is heated to 1530 °C for sintering for 3 hours to obtain a sphere for ceramic ball valve.

[0057] Example 7 This embodiment provides a valve core assembly, such as Figure 4 As shown, the device includes the ball 1 and valve seat 2 prepared in Example 1. The ball 1 is rotatably assembled in the inner fitting space of the valve seat 2. The ball 1 is provided with a ball flow channel hole 11 in the middle, and the valve seat 2 is provided with a valve seat flow channel hole 21 in the middle. The micron-level pit array 12 on the surface of the ball 1 is filled with polyperfluoroalkyl ether (PFPE) grease. A disc spring 3 is provided on the back side of the valve seat 2 away from the sealing surface of the ball 1 (i.e., the side that does not contact the ball). The disc spring 3 can provide a force to the valve seat 2 towards the ball 1, so that the sealing surface of the valve seat 2 and the ball 1 forms an initial sealing pressure after assembly, ensuring the initial sealing performance. On the other hand, during the long-term use of the valve, if the sealing surface of the valve seat 2 and the ball 1 is worn, or the components are slightly deformed due to changes in operating conditions, the disc spring 3 can automatically adjust the pressure on the valve seat 2 through its own elastic deformation, so as to achieve dynamic compensation of the sealing effect and avoid media leakage.

[0058] Figure 5 The flowcharts for the sphere preparation methods in Examples 1-6 are shown, which mainly include five steps: preparing ceramic slurry, establishing a sphere model, 3D printing of sphere green bodies and thermal debinding and sintering.

[0059] Performance Testing and Result Analysis The spheres prepared in Examples 1-6 were subjected to performance tests, and the test results are shown in Table 1: Table 1 Performance test data of the spheres prepared in Examples 1-6 The data in the table show that the spheres obtained in Examples 1-6 have a bending strength ≥1200 MPa, a compressive strength ≥2100 MPa, and a fracture toughness K. IC ≥12 MPa·m¹ / ², hardness HRA≥88. The spheres prepared in Examples 1-6, when fitted with metal valve seats, exhibit a friction coefficient between 0.02 and 0.05 under simulated deep-sea pressure (70 MPa) and H2S-containing media conditions, a starting torque of 20-25 N·m, and after 1000 pressure cycles and 300,000 opening and closing tests, zero leakage and no "seizing" are observed in the seal, and the sphere shows no corrosion or macroscopic wear.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ball for a ceramic ball valve, characterized in that, The sphere (1) is integrally formed from zirconia-based ceramic material using 3D printing technology. A valve stem groove (13) is opened at one top of the sphere (1). A sphere flow channel hole (11) is provided in the middle of the sphere (1). A micron-level pit array (12) is provided on the spherical surface of the sphere (1). The base part of the sphere (1) and the micron-level pit array (12) are an integral structure with continuous material and no bonding interface. The micron-level pit array (12) is functionally gradient distributed on the surface of the sphere (1). That is, the distribution density of the micron-level pit array (12) in the main sealing ring area (14) of the sphere (1) is higher than the distribution density in its end area (15). The size of the micron-level pit in the main sealing ring area (14) is smaller than the size of the micron-level pit in the end area (15).

2. The ball for a ceramic ball valve according to claim 1, characterized in that, The shape of the micron-sized pit is one or more of the following: circular, elliptical, teardrop-shaped, fish-scale-shaped, honeycomb-shaped, and having a parabolic profile.

3. The ball for a ceramic ball valve according to claim 1, characterized in that, In the main sealing ring area (14), the coverage area of ​​the micron-sized pits accounts for 40%-50% of the area of ​​the main sealing ring area (14), and the maximum size of the micron-sized pits is 20-30 μm; in the end area (15), the coverage area of ​​the micron-sized pits accounts for 20%-30% of the area of ​​the end area (15), and the maximum size of the micron-sized pits is 40-50 μm.

4. The ball for a ceramic ball valve according to claim 1, characterized in that, At the opening edge of the micron-level pit, the boundary region of the spherical surface of the sphere (1) that is recessed downwards is a smooth rounded corner structure (123), and the radius of the rounded corner structure (123) is 3-8 μm.

5. The ball for a ceramic ball valve according to claim 1, characterized in that, The zirconia-based ceramic material comprises the following raw materials in the following molar proportions: 100 parts ZrO2, 2-4 parts Y2O3, 2-4 parts CeO2, 4-12 parts Al2O3, and 0.2-2 parts TiO2.

6. A method for preparing a ball for a ceramic ball valve as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Three-dimensional modeling: Establish a three-dimensional digital model of the ball used in the ceramic ball valve, and pre-enlarge the three-dimensional digital model according to the shrinkage rate of the zirconia-based ceramic material to obtain the ball model; S2. Additive manufacturing: Based on the spherical model described in step S1, zirconia-based ceramic slurry is 3D printed into a spherical green body; S3, hot degreasing and sintering: The spherical green body described in step S2 is cleaned, hot degreased and sintered to obtain a sphere (1) with an integrally formed micron-level pit array (12).

7. The method for preparing the ball for a ceramic ball valve according to claim 6, characterized in that, The 3D printing described in step S2 uses digital light processing technology or stereolithography technology.

8. The method for preparing the ball for a ceramic ball valve according to claim 6, characterized in that, The thermal degreasing in step S3 is carried out in an air atmosphere, with a heating rate of 5-10 ℃ / h, a holding temperature of 500-600 ℃, and a time of 1-4 h.

9. The method for preparing a ball for a ceramic ball valve according to claim 6, characterized in that, The sintering temperature in step S3 is 1500-1600 ℃, the atmosphere is air, and the time is 1-4 h.

10. A valve core assembly comprising a ball (1) as described in any one of claims 1-5 and a valve seat (2) cooperating therewith, characterized in that, An elastic element is provided on the back side of the valve seat (2) away from the sealing surface of the ball (1). The elastic element is used to apply pressure to the valve seat (2) toward the ball (1) to form an initial seal and to automatically adjust the pressure on the valve seat (2) through its own elastic expansion and contraction to achieve dynamic compensation of the sealing effect.

11. The valve core assembly according to claim 10, characterized in that, The elastic element is a disc spring (3).

12. A ball valve, characterized in that, The ball used in the ceramic ball valve is as described in any one of claims 1-5.

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