Butterfly valve with double-geometric-circle five-eccentric structure

Abstract

The invention relates to the technical field of fluid control valves, in particular to a double-geometric-circle five-eccentric-structure butterfly valve which comprises five asymmetric structures. The rotating axis of a valve clack deviates A in the radial direction relative to the center of a sealing face. The geometric center of the valve clack deviates B perpendicular to the pipeline axis; the connecting line of the highest points of the valve seat sealing surface and the normal center line of the connecting section jointly form an included angle C with the axis of the pipeline; the center connecting line of the two arcs and the pipeline axis form an included angle D; and the two arcs are smoothly connected through a transition fillet RA. Opening and closing friction-free separation and space progressive sealing contact can be achieved, the operation torque is remarkably reduced, and the sealing reliability and durability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid control valves, and particularly relates to a double-geometric circular five-eccentric structure butterfly valve. BACKGROUND

[0002] As a kind of fluid control device widely used in petroleum, chemical industry, electric power, metallurgy and municipal water supply and drainage fields, butterfly valve is favored due to its compact structure, rapid opening and closing, small operation torque and other advantages. Traditional butterfly valve usually adopts single eccentric or double eccentric structure, which offsets the axis of valve stem from the sealing center of valve seat or the geometric center of valve plate, so as to reduce the friction between valve disc and sealing surface during opening and closing, thereby improving the sealing performance and prolonging the service life. However, under high pressure difference, high wear or severe working conditions, the existing eccentric butterfly valve still has problems such as insufficient sealing reliability, large opening and closing torque, easy jamming or leakage. Especially when the medium contains particles or has strong corrosiveness, the conventional structure is difficult to meet the dual requirements of low operation torque and high sealing grade. In recent years, although three eccentric or even four eccentric butterfly valves have been proposed, trying to optimize the sealing contact state through multiple bias, but the sealing surface adopts single curvature profile, resulting in short sealing contact line, uneven stress distribution, and local interference at full closed position or large friction at initial opening. In addition, the existing design lacks fine regulation of the geometric matching relationship between the valve plate and the valve seat, and it is difficult to realize frictionless movement and reliable fitting of metal hard sealing in the whole stroke. Therefore, a new type of butterfly valve structure is needed, which introduces multiple asymmetric geometric characteristics, systematically coordinates the spatial relationship between the rotation center, the sealing surface profile and the pipeline axis, ensures low opening and closing torque, and significantly improves the sealing area and sealing stability, so as to meet the urgent needs of high-end industrial fields for high-performance butterfly valves. SUMMARY

[0003] The present application provides a double-geometric circular five-eccentric structure butterfly valve which is innovative in structure, clear in geometric relationship and can be implemented in engineering. The butterfly valve forms a five-fold asymmetric geometric eccentric relationship between the valve disc and the valve seat, so that the sealing pair forms a spatial progressive contact during closing, and realizes frictionless separation at the initial stage of opening, thereby achieving the coordinated goals of high sealing specific pressure, low operation torque and long service life without relying on elastic elements or high pre-tightening force.

[0004] The present application provides a butterfly valve for controllable fluid flow, which has a five-fold asymmetric structure formed by the sealing pair of the valve disc and the valve seat, specifically including the following five eccentric features:

[0005] The first eccentricity is that the rotation axis of the valve disc, i.e. the center line of the valve stem, is offset from the overall geometric center of the sealing surface by a fixed distance A in the radial direction of the pipeline; when the valve starts to open from the closed state, the rotation center deviates from the center of the sealing surface, avoiding sliding friction of the sealing surface during opening and closing; this structural feature significantly reduces the frictional power consumption during opening and closing, and reduces the surface damage of the sealing material caused by repeated friction.

[0006] Further, the second eccentricity is that the geometric center of the valve disc body is offset by a distance B to the side of the pipe wall in the direction perpendicular to the pipeline axis; the offset B is in the range of 3mm to 10mm; this offset design makes the position of the valve disc in the flow passage asymmetrically distributed, optimizes the fluid flow path, reduces the local flow velocity gradient, and thus reduces the impact torque of the fluid on the back surface of the valve disc; at the same time, the eccentricity and the first eccentricity work together to make the center of gravity trajectory of the valve disc present a non-circular arc path during rotation, further weakening the dynamic unbalanced force during opening and closing, and improving the operation stability.

[0007] In particular, the third eccentricity is reflected in the profile configuration of the valve seat sealing surface: the valve seat sealing surface is composed of two independently defined circular segments, i.e. circle 10 and circle 11, which are tangentially connected by a connecting segment in the middle region; the highest point of circle 10 is P1, and the highest point of circle 11 is P2, forming a line segment connecting P1 and P2; at the same time, the geometric center of the middle connecting segment is taken as its normal center line; the line segment P1P2 and the normal center line together determine a reference direction; the reference direction and the pipeline axis form an included angle C, and the included angle C is in the range of 5° to 15°; this inclined arrangement makes the valve disc start sealing contact on one side of the valve seat during closing, and gradually expand to the entire sealing width along the reference direction, forming a gradual pressing effect in time and space; this gradual contact mechanism makes the sealing pressure more uniform in the circumferential direction, avoiding local overload or underpressure, and improving the sealing integrity.

[0008] Further, the fourth eccentricity is that the line connecting the geometric center O1 of circle 10 and the geometric center O2 of circle 11 forms an included angle D with the pipeline axis; the included angle D is in the range of 3° to 10°; the spatial offset of the circle relative to the ordinary three-eccentric elliptical shape makes the two circular segments not symmetrically arranged in the same plane, but in a three-dimensional staggered arrangement; when the valve disc is rotated to close, the contact trajectory of its sealing edge with the valve seat is no longer a planar curve, but a spatial spiral contact line; this three-dimensional contact form enhances the self-adaptability of the sealing pair to the thermal expansion difference of the valve body or valve disc due to temperature changes, or the elastic deformation caused by internal pressure; even in the case of slight deformation of the valve body, the sealing contact can still maintain a continuous and effective pressing sealing state.

[0009] The fifth eccentricity is as follows: the circle 10 and the circle 11 are not directly connected by a straight line segment, but are smoothly connected by a guiding transition fillet RA; this fillet structure eliminates the sharp corners at the traditional straight edge connection, avoiding the initiation of micro-cracks at the sealing edge caused by stress concentration; at the same time, the fillet participates in the sealing contact during the valve disc closing process, effectively increasing the actual contact area of ​​the sealing pair; in addition, the smooth transition profile improves the flow state of the fluid near the sealing area, reduces boundary layer separation and eddy current generation, and reduces the erosion rate of the sealing edge by the medium.

[0010] The "double geometric circle" refers to the valve seat sealing surface being composed of two independently defined arc segments, each with a definite geometric center and radius; the two arc segments are oriented in space according to the aforementioned included angles C and D, and are connected by a transition fillet RA to achieve continuous curvature, forming a C-shaped arc. 1 A continuous sealing profile curve; this profile curve forms a conformal contact with the valve disc sealing edge during valve disc rotation and closure, ensuring a uniform contact stress distribution across the entire sealing width.

[0011] Furthermore, the contour of the valve disc sealing edge is conjugate with the contour of the valve seat sealing surface, so that its contour strictly matches the double geometric circular five-eccentric structure of the valve seat.

[0012] In particular, the parameter combination of the five-fold eccentric structure must meet the kinematic compatibility condition: during the process of the valve disc rotating from the fully open position to the fully closed position, this kinematic characteristic is verified by multibody dynamics simulation and prototype testing to ensure that each eccentric parameter A, B, C, D and RA works in coordination within a given range without causing motion interference or sealing failure.

[0013] Among them, the first eccentricity A and the second eccentricity B together determine the spatial position of the valve disc rotation center; the third eccentricity C and the fourth eccentricity D together define the spatial orientation of the valve seat sealing surface; and the fifth eccentricity RA determines the continuity of the sealing surface profile and the stress distribution characteristics. The five together constitute an inseparable geometric system, and any change in any parameter will affect the optimal matching relationship of the other parameters. Therefore, in engineering implementation, it is necessary to perform joint optimization of the five parameters based on finite element contact analysis and fluid-structure interaction simulation to obtain the best combination of sealing performance and operational performance under specific working conditions.

[0014] The beneficial effects of this invention are as follows: Through the synergistic effect of the first and second eccentricities, the valve disc disengages from the sealing contact in the initial opening stage, reducing the opening and closing torque by more than 40%; through the spatial progressive contact mechanism of the third and fourth eccentricities, the standard deviation of the sealing specific pressure along the circumferential direction is controlled within ±8%, significantly better than the ±20% of the traditional triple-eccentric butterfly valve; through the transition fillet RA of the fifth eccentricity, the maximum principal stress at the sealing edge is reduced by 35%, and the fatigue life is extended by more than 2 times; under operating conditions with temperature changes of ±150℃ or internal pressure fluctuations of ±10MPa, the sealing leakage rate can still be maintained at ISO 5208A level (≤1×10). - 6 The flow resistance coefficient ζ is below 0.15, which is better than the 0.25–0.35 range of conventional butterfly valves. All of the above technical indicators have been verified by third-party testing institutions in accordance with API 598, ISO 5208 and ASME B16.34 standards.

[0015] In summary, this invention integrates the kinematic, contact mechanics, and fluid dynamics characteristics of the sealing pair into a single structural system by precisely constructing a five-fold asymmetric geometric eccentric relationship. This solves the technical contradiction of traditional butterfly valves in balancing sealing performance, operability, and durability under harsh operating conditions, providing a structural solution for high-performance industrial valves that is mass-producible, parameter-controllable, and performance-stable. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the sealing pair structure of a double-geometric circular five-eccentric butterfly valve according to the present invention.

[0017] Legend:

[0018] A. The offset between the valve disc rotation point and the center of the sealing surface;

[0019] B. The offset of the valve plate's geometric center from the pipe axis towards the pipe wall;

[0020] C. The angle between the reference direction formed by the line connecting the highest point of circle 10 and the highest point of circle 11 and the center line of the straight edge and the pipe axis;

[0021] D. The angle between the line connecting the center point of circle 10 and the center point of circle 11 and the axis of the pipe;

[0022] RA, the guide transition fillet from circle 10 to circle 11;

[0023] Circular 10, the first arc segment of the valve seat sealing surface;

[0024] Circular 11, the second arc segment of the valve seat sealing surface. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Specific implementation examples are given below.

[0027] The following describes in detail a specific embodiment of a double-geometric circular five-eccentric butterfly valve according to the present invention, with reference to the accompanying drawings; for example... Figure 1 As shown, this embodiment provides a butterfly valve for use in high-pressure, high-temperature or corrosive media conditions. Its core lies in the five-fold asymmetric geometric eccentric relationship constructed between the valve disc and the valve seat. This structure achieves spatial progressive contact of the sealing pair during the closing process and frictionless disengagement during the initial opening stage by precisely controlling the spatial arrangement and mutual cooperation of each eccentric parameter. This achieves the technical goals of high sealing specific pressure, low operating torque and long service life.

[0028] In this embodiment, the butterfly valve as a whole includes main components such as a valve body, valve disc, valve stem, and valve seat sealing surface. The valve disc is installed in the valve body cavity via the valve stem and can rotate around the valve stem centerline to open and close the flow channel. A key structural feature is the five-fold eccentric structure between the valve disc and the valve seat sealing surface, specifically as follows: First, the first eccentricity is that the rotation axis of the valve disc, i.e., the valve stem centerline, is offset by a fixed distance A relative to the overall geometric center of the sealing surface along the radial direction of the pipeline. When the valve starts to open from the fully closed state, because the rotation center is offset from the center of the sealing surface, sliding friction on the sealing surface is avoided during the opening and closing process. This structural feature significantly reduces frictional power consumption during the opening and closing process, while also reducing surface damage to the sealing material caused by repeated friction.

[0029] Secondly, the second eccentricity is manifested in the geometric center of the valve disc body being offset by a distance B to one side of the pipe wall in a direction perpendicular to the pipe axis. In this embodiment, this offset design makes the valve disc position in the flow channel asymmetrically distributed, optimizing the fluid flow path and reducing the local velocity gradient, thereby reducing the impact torque of the fluid on the back of the valve disc. At the same time, this eccentricity and the first eccentricity work together to make the center of gravity trajectory of the valve disc follow a non-circular arc path during rotation, further weakening the dynamic imbalance force during opening and closing and improving operational stability. For example, in a DN300 steam pipeline system with a working pressure of 10MPa, this structure can effectively suppress valve disc vibration caused by high-speed fluid impact and improve the system's operational stability.

[0030] The third eccentricity is reflected in the contour structure of the valve seat sealing surface; such as Figure 1As shown, the valve seat sealing surface is composed of two independently defined circular arc segments—circle 10 and circle 11—which are tangentially connected in the middle region by a connecting segment. The highest point of circle 10 is defined as P1, and the highest point of circle 11 is defined as P2. Connecting P1 and P2 forms a line segment. Simultaneously, the geometric center of the middle connecting segment is taken, and its normal centerline is drawn. The line segment P1P2 and this normal centerline together determine a reference direction. This reference direction forms an angle C with the pipe axis. In this embodiment, the angle C is 10°. The arrangement ensures that during valve disc closure, the sealing contact begins on one side of the valve seat and gradually expands along the reference direction to the entire sealing width, creating a progressive compression effect in both time and space. For example, during closure, when the valve disc rotates to 15° from the fully closed position, only the circular 10 area begins to contact; as it continues to rotate to 5°, the transition fillet RA area participates in the contact; finally, in the fully closed position, the entire sealing surface achieves uniform compression. This progressive contact mechanism makes the sealing pressure distribution more uniform along the circumference, avoiding local overload or underpressure and improving sealing integrity.

[0031] The fourth eccentricity is manifested in the fact that the line connecting the geometric center O1 of circle 10 and the geometric center O2 of circle 11 forms an angle D with the pipeline axis; this spatial offset causes the two arc segments to be arranged symmetrically in the same plane, but in a three-dimensional staggered arrangement; when the valve disc rotates to close, the contact trajectory between its sealing edge and the valve seat is no longer a planar curve, but a spatial spiral contact line; this three-dimensional contact form enhances the adaptive ability of the sealing pair to the thermal expansion difference of the valve body or valve disc caused by temperature changes, or the elastic deformation caused by internal pressure; for example, when the temperature rises from room temperature to 350°C, the valve body and valve disc will undergo micron-level deformation due to the different thermal expansion coefficients of the materials, and traditional butterfly valves are prone to local leakage, while the present invention can still maintain continuous and effective sealing contact due to the three-dimensional staggered sealing structure;

[0032] The fifth eccentricity is manifested in the fact that circles 10 and 11 are not directly connected by a straight segment, but are smoothly connected by a guiding transition fillet RA. This fillet structure eliminates the sharp corners at the traditional straight-edge connection, avoiding the initiation of micro-cracks at the sealing edge caused by stress concentration. At the same time, this fillet participates in the sealing contact during the valve disc closing process, effectively increasing the actual contact area of ​​the sealing pair. In addition, this smooth transition profile improves the flow state of the fluid near the sealing area, reduces boundary layer separation and eddy current generation, and reduces the erosion rate of the sealing edge by the medium. In the case of conveying slurry containing solid particles, this structure significantly extends the erosion resistance life of the sealing surface.

[0033] The valve is oriented and the curvature is continuously connected through transition fillets to form a continuous C1 sealing profile curve. This profile curve forms a conformal contact with the valve sealing edge during the valve disc rotation and closing process, ensuring a uniform contact stress distribution across the entire sealing width.

[0034] The contour of the valve disc sealing edge is conjugate with the contour of the valve seat sealing surface. During the manufacturing process, the valve disc sealing surface is precision ground by a CNC five-axis linkage grinding machine so that its contour strictly matches the double geometric circular five-eccentric structure of the valve seat.

[0035] The parameter combination of the five-fold eccentric structure must meet kinematic compatibility conditions. In this embodiment, a virtual prototype model was established using the multibody dynamics simulation software ADAMS to verify that during the process of the valve disc rotating from the fully open position (90°) to the fully closed position (0°), the minimum gap between the valve disc sealing edge and the valve seat sealing surface is always greater than 0.12mm during the opening phase (0°–85°), ensuring no contact. In the final 5° rotation range of closing (5°–0°), the contact pressure increases linearly from zero to the designed sealing pressure of 45MPa. This kinematic characteristic was verified by actual measurement on a physical prototype using a laser displacement sensor and strain gauges. The error between the measured data and the simulation results is less than 5%.

[0036] In actual operation, when the valve is fully open, the valve disc rotates to 90°, the flow path is completely unobstructed, and the measured flow resistance coefficient ζ is 0.13, which is better than the 0.25–0.35 range of conventional butterfly valves. When the valve needs to be closed, the drive device drives the valve stem to rotate clockwise, and the valve disc begins to move towards the closed position. When the rotation angle is greater than 5°, the valve disc sealing edge and the valve seat sealing surface remain in a non-contact state, and the operating torque is only 55% of that of a traditional triple-eccentric butterfly valve. When the rotation is within 5°, the valve disc sealing edge first contacts the circular 10 area, and then gradually expands to the transition rounded corner RA area, finally achieving a full circumferential seal at the 0° position. Due to the combined effect of the third eccentric C and the fourth eccentric D, the sealing contact unfolds along the spatial spiral path, so that the sealing specific pressure along the circumferential standard deviation is controlled within ±6.5%, which is significantly better than ±20% of the traditional triple-eccentric butterfly valve. After temperature cycling test (-20℃ to +350℃, 100 cycles), the sealing leakage rate still remains within ISO. 5208A grade (≤1×10 -6 Below mbar·L / s, meeting the requirements of API 598 and ASME B16.34 standards;

[0037] In summary, this embodiment integrates the kinematics, contact mechanics, and fluid dynamics characteristics of the sealing pair into a single structural system by precisely constructing a five-fold asymmetric geometric eccentric relationship. This solves the technical contradiction of traditional butterfly valves in balancing sealing performance, operability, and durability under harsh operating conditions, and provides a structural solution for high-performance industrial valves that is mass-producible, parameter-controllable, and performance-stable.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double geometry circular five-eccentric butterfly valve comprising a valve body, a valve disc, a valve stem and a valve seat sealing surface, characterized in that: The valve disc and the valve seat sealing surface form a sealing pair with five asymmetric geometric eccentric relationships; The first eccentricity is that the center line of the valve stem is offset by a fixed distance A in the radial direction of the pipeline relative to the overall geometric center of the sealing surface The second eccentricity is that the geometric center of the valve disc body is offset by a distance B to one side of the pipe wall in a direction perpendicular to the pipeline axis, and the value range of B is 3mm to 10mm; The third eccentricity is that the valve seat sealing surface is composed of two independently defined circular arc segments of circle 10 and circle 11, the highest point P1 of circle 10 and the highest point P2 of circle 11 are connected, and the normal center line of the geometric center of the intermediate connecting segment determines a reference direction, and the reference direction and the pipeline axis form an included angle C, and the value range of C is 5° to 15°; The fourth eccentricity is that the line connecting the geometric center O1 of circle 10 and the geometric center O2 of circle 11 forms an included angle D with the pipeline axis, and the value range of D is 3° to 15°; The fifth eccentricity is that circle 10 and circle 11 are smoothly connected through a guide transition fillet RA.

2. The double-giomeriy circular five-eccentricity butterfly valve of claim 2, wherein: The profile of the valve disc sealing edge and the profile of the valve seat sealing surface are conjugate, and the valve disc sealing surface is surface-hardened with a hard alloy layer, and the thickness of the hardening layer is not less than 1.5mm.

3. The double-giomeriy circular five-eccentricity butterfly valve as claimed in claim 1, wherein: The circular 10 and the circular 11 are connected in curvature continuity by guiding the transition fillet RA, forming a C 1 Continuous sealing profile curve.

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