Three-eccentric center butterfly valve sealing ring and improvement method

Abstract

The invention discloses a three-eccentric center butterfly valve sealing ring and an improvement method, the sealing ring comprises a circular ring main body and a boss which are distributed inside and outside and connected into a whole, and an annular groove is formed between the circular ring main body and the boss. The groove can provide deformation compensation, and when the butterfly plate is turned outwards and deformed, an accommodating space can be provided for the movement of the sealing ring towards the sealing surface of the valve body, so that the damage of the sealing ring caused by extrusion is reduced, and the integrity and the sealing effect of the sealing surface are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of butterfly valve technology, specifically to a triple eccentric butterfly valve sealing ring and its improvement method. Background Technology

[0002] Triple eccentric butterfly valves are widely used in high-pressure pipeline systems in petroleum, chemical, and power industries due to their excellent sealing performance and low operating torque. Their core structure employs a combined design of eccentric butterfly plate axis, valve body axis, and sealing surface, achieving frictionless opening and closing and zero leakage. However, in high-pressure (e.g., Class 600 and above) or large-diameter (DN>300) conditions, traditional triple eccentric butterfly valves face a serious risk of structural failure (the risk is lower in low-pressure and small-diameter applications, but it still has some impact). This is mainly manifested in the butterfly plate undergoing asymmetric elastic deformation (commonly known as "outward buckling") with the valve stem as the fulcrum after being impacted by fluid pressure. The specific reasons are as follows:

[0003] (1) Insufficient structural stiffness:

[0004] As a thin-walled disc structure, the butterfly plate exhibits a cantilever effect under unidirectional fluid pressure. The edge of the butterfly plate furthest from the valve stem bears a huge bending moment. If the butterfly plate is insufficiently thick or lacks a rigid reinforcing structure, it will bend and deform towards the low-pressure side. Figure 3 The image shows a cross-sectional view of a triple eccentric butterfly valve, including a valve body 01, a valve plate 02, a sealing ring 03, and a pressure ring 04. The sealing ring 03 is mounted on the valve plate 02 via the pressure ring 04 and bolts, thus forming a butterfly plate. The outer circumference (sealing surface) of the sealing ring 03 cooperates with the sealing surface of the valve body 01 to achieve a seal. The downward arrow indicates the direction of fluid medium flow. Since the valve stem fixes the center position of the valve plate 02, the butterfly plate, as a thin-walled disc structure, generates a cantilever effect under unidirectional fluid pressure. The edge of the butterfly plate away from the valve stem bears a huge bending moment. If the butterfly plate thickness is insufficient or lacks a rigid reinforcement structure, it will bend and deform towards the low-pressure side, as shown by the inward bending arrow.

[0005] (2) Valve stem support system overload:

[0006] The single-stem design concentrates the fluid load on a single shaft. Under high pressure, the stem undergoes torsional deformation, causing the disc to deflect. In addition, the stem bearing housing experiences micro-displacement due to local stress concentration, further amplifying the "outward" displacement of the disc edge.

[0007] (3) Fluid dynamic disturbances:

[0008] When the valve is partially open, a non-uniform pressure distribution (vortex / low-pressure zone) is formed on the back flow surface of the butterfly plate, which induces local buckling deformation.

[0009] All three of the above situations will cause the valve plate to "turn outwards" on both sides. Specifically, for example... Figure 4As shown, the butterfly plate edge undergoes slight backward and inward deformation, causing the sealing surface on one side of the sealing ring 03 to move outward, as indicated by the left arrow. This compresses the sealing surface, leading to sealing performance failure. Meanwhile, the sealing surface on the other side moves inward, as indicated by the right arrow, with less impact on the sealing surface. This deformation directly damages the precisely designed triple eccentric seal geometry, resulting in broken sealing contact lines, extremely uneven contact stress distribution (coexistence of local overload and local failure), and triggering dynamic wear, erosion, and accelerated material degradation. The ultimate result is that the valve completely loses its "zero leakage" capability under high pressure and large diameter conditions, exhibiting severe internal or even external leakage, and reduced sealing performance.

[0010] In the prior art, common improvement methods for the sealing ring structure are as follows:

[0011] For example, the Chinese invention with publication number CN221569446U and title "A Butterfly Valve Sealing Ring" discloses a butterfly valve sealing ring with alternating layers of metal plates and graphite plates. The layers are bonded together with adhesive, and the overall structure is enhanced by through pin holes and pins welded to both ends. This design significantly improves the structural strength and integrity of the sealing ring itself, but it does not involve improving the sealing ring structure to alleviate butterfly plate deformation. Therefore, it cannot effectively prevent the sealing surface damage and wear caused by butterfly plate deformation.

[0012] For example, Chinese patent CN215257884U discloses a sealing ring for butterfly valves. It proposes a butterfly valve sealing ring mainly made of non-metallic materials (high-density sponge silicone and polytetrafluoroethylene PTFE body with anti-corrosion layer). The ring has connecting pads on both sides of the notch and suction cup openings on the ring body. It aims to improve the initial sealing performance and service life under specific working conditions (such as corrosive environments). Although this solution has cost advantages and initial sealing performance under specific conditions, its non-metallic materials are prone to aging and wear, and have limited temperature and pressure resistance. It is prone to rapid failure under harsh working conditions. More importantly, this structural optimization also fails to solve the problem of butterfly plate deformation. After long-term operation, butterfly plate deformation will still cause severe wear on the sealing surface, eventually leading to leakage.

[0013] Therefore, providing a triple eccentric butterfly valve sealing ring and an improved method is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0014] In view of this, the present invention provides a triple eccentric butterfly valve sealing ring and an improved method to solve technical problems such as butterfly plate "outward turning", easy wear of butterfly valve sealing surface and reduced fatigue life in the traditional butterfly valve and its improved design process.

[0015] To achieve the above objectives, the present invention adopts the following technical solution:

[0016] A triple-eccentric butterfly valve sealing ring includes an inner and outer ring body and a boss that are distributed and connected as one piece, so as to form an annular groove between the ring body and the boss.

[0017] By adopting the above technical solutions, the beneficial effects of the present invention are as follows:

[0018] The groove can provide deformation compensation. When the butterfly plate deforms outward, it can provide room for the sealing ring to move towards the valve body sealing surface, thereby reducing the damage to the sealing ring caused by compression and ensuring the integrity of the sealing surface and the sealing effect.

[0019] Furthermore, a groove is provided on the back of the boss for the insertion of screws that are fixed to the valve plate.

[0020] The beneficial effect of adopting the above-mentioned further technical solution is that it provides circumferential positioning of the back of the boss, preventing it from sliding or misaligning during operation.

[0021] Furthermore, the height of the boss is greater than the height of the ring body.

[0022] The beneficial effect of adopting the above-mentioned further technical solution is that the bolt passes through the pressure ring and is screwed into the boss, thereby increasing the screwing depth and increasing the connection tightness.

[0023] Furthermore, the depth of the annular groove is 5 mm.

[0024] Furthermore, the outer circumferential surface of the ring body is provided with a weld overlay layer.

[0025] The beneficial effects of adopting the above-mentioned further technical solution are that it not only enhances the fit between the outer circumferential surface (sealing surface) of the ring body and the sealing surface of the valve body, but also improves corrosion resistance and wear resistance, thereby significantly improving sealing performance.

[0026] An improved method for the sealing ring of a triple eccentric butterfly valve, as described above, includes the following steps:

[0027] S1: Establish a three-dimensional solid model of the sealing ring, and mesh the three-dimensional model of the sealing ring to form several mesh units;

[0028] S2: Add definition of the material used for the sealing ring in actual working conditions, and further define the physical parameters of the materials of each component in the solid model;

[0029] S3: Based on the actual working environment of the sealing ring, assemble it with the pressure ring and valve plate to make the sealing ring fit with the valve body sealing surface, and assign values ​​to the medium pressure, torque and friction parameters of the solid model.

[0030] S4: After assigning parameter values ​​to the solid model, perform topology optimization simulation analysis, and determine the location of uneven stress distribution on the sealing ring based on the results;

[0031] S5: Based on the results, reconstruct the sealing ring, and repeat steps S2 and S3. Simulation analysis yields the displacement and stress cloud maps of the solid model.

[0032] S6: Based on the result cloud map, improve the location of stress concentration in the reconstructed solid model.

[0033] Therefore, the present invention provides a triple eccentric butterfly valve sealing ring and an improved method, which, compared with the prior art, has the following beneficial effects:

[0034] 1) This invention achieves and maintains zero-leakage sealing under high-pressure, large-diameter operating conditions;

[0035] 2) This invention significantly extends the service life of valves and sealing pairs;

[0036] 3) This invention can reduce valve operating torque and energy consumption;

[0037] 4) This invention improves the structural safety of the valve and the operational reliability of the system;

[0038] 5) This invention expands the application range of valves at higher pressures and larger diameters;

[0039] 6) This invention effectively reduces the overall cost of the valve throughout its entire life cycle. Attached Figure Description

[0040] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 The attached figure is a structural schematic diagram of a triple eccentric butterfly valve sealing ring provided by the present invention;

[0042] Figure 2 The attached figure is a structural schematic diagram of a triple eccentric butterfly valve sealing ring provided by the present invention from another perspective;

[0043] Figure 3 The attached figure is a schematic diagram of the structure of a triple eccentric butterfly valve in the prior art;

[0044] Figure 4 The attached image is... Figure 3 A magnified schematic diagram of the central part of the structure. Detailed Implementation

[0045] 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.

[0046] like Figure 1-4 As shown in the figure, this invention discloses a triple-eccentric butterfly valve sealing ring, comprising an inner and outer ring body 1 and a boss 2 that are distributed internally and externally and connected as a single unit, forming an annular groove 3 between the ring body 1 and the boss 2. In this embodiment, the depth of the annular groove 3 is 5 mm, and the wall thickness of the ring body 1 is 10 mm. The annular groove 3 of this invention can provide deformation compensation. When the butterfly plate undergoes outward deformation, it can provide accommodating space for the sealing ring to move towards the valve body sealing surface, thereby reducing the damage to the sealing ring caused by compression and ensuring the integrity of the sealing surface and the sealing effect.

[0047] To further optimize the technical solution of the present invention, a groove 21 is provided on the back of the boss 2. In this embodiment, the groove 21 is a circular groove for the screws fixed on the valve plate 02 to be inserted, thereby circumferentially positioning the back of the boss 2 and preventing it from sliding or misaligning during operation.

[0048] To further optimize the technical solution of the present invention, the height of the boss 2 is greater than the height of the ring body 1. In this embodiment, the boss 2 is 10.5mm higher than the ring body. This increases the tightening depth and connection tightness when the bolt passes through the pressure ring 04 and is screwed into the boss 2.

[0049] Understandably, the value by which the boss 2 is higher than the circular body 1 is determined by butterfly valves of different diameters.

[0050] To further optimize the technical solution of the present invention, a weld overlay layer is provided on the outer circumference of the ring body 1. In this embodiment, the weld overlay layer is 2mm thick, which not only enhances the fit between the outer circumference of the ring body 1 (sealing surface) and the sealing surface of the valve body 01, but also improves corrosion resistance and wear resistance, thereby significantly improving the sealing performance.

[0051] This invention also discloses an improved method for a triple eccentric butterfly valve sealing ring as described above, comprising the following steps:

[0052] S1: Establish a three-dimensional solid model of the sealing ring, and mesh the three-dimensional model of the sealing ring to form several mesh units;

[0053] S2: Add definition of the material used for the sealing ring in actual working conditions, and further define the physical parameters of the materials of each component in the solid model;

[0054] S3: Based on the actual working environment of the sealing ring, assemble it with the pressure ring and valve plate to make the sealing ring fit with the valve body sealing surface, and assign values ​​to the medium pressure, torque and friction parameters of the solid model.

[0055] S4: After assigning parameter values ​​to the solid model, perform topology optimization simulation analysis, and determine the location of uneven stress distribution on the sealing ring based on the results;

[0056] S5: Based on the results, reconstruct the sealing ring, and repeat steps S2 and S3. Simulation analysis yields the displacement and stress cloud maps of the solid model.

[0057] S6: Based on the result cloud map, improve the location of stress concentration in the reconstructed solid model.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A seal ring for a triple offset butterfly valve, characterized in that, The annular body and the boss are integrally connected and distributed inside and outside to form an annular groove between the annular body and the boss.

2. A seal ring for a triple offset butterfly valve according to claim 1, wherein, A groove is formed on the back of the boss for a screw to be inserted to fix the boss on the valve plate.

3. A seal ring for a triple offset butterfly valve according to claim 1 or 2, characterised in that The height of the boss is greater than the height of the annular body.

4. A seal ring for a triple offset butterfly valve according to claim 1, wherein, The depth of the annular groove is 5mm.

5. A seal ring for a triple offset butterfly valve according to claim 1, wherein, The circumference of the annular body is provided with a cladding layer.

6. An improved method of manufacturing a seal ring for a triple offset butterfly valve as claimed in any one of claims 1 to 5, wherein, The method comprises the following steps: S1: a three-dimensional solid model of the sealing ring is established, and the three-dimensional model of the sealing ring is meshed to form a plurality of mesh units; S2: the material used by the sealing ring in the actual working condition is added, and the physical parameters of the material of each component of the solid model are further defined; S3: according to the working environment of the sealing ring in the actual working condition, the sealing ring is assembled with the pressure ring and the valve plate, the sealing ring is matched with the sealing surface of the valve body, and the medium pressure, torque and friction force parameters of the solid model are assigned; S4: after the solid model is assigned with the parameter values, topological structure optimization simulation analysis is performed, and the position of uneven stress distribution on the sealing ring is determined according to the result; S5: the sealing ring is reconstructed according to the result, and the steps S2 and S3 are implemented again, and the displacement result cloud map and the stress result cloud map of the solid model are obtained through simulation analysis; S6: the stress concentration position in the reconstructed solid model is improved according to the result cloud map.

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