Floating hard seal butterfly valve

Abstract

This utility model discloses a floating hard-seal butterfly valve, relating to the field of butterfly valve technology, to address the sealing problem caused by off-axis deformation. The valve seat assembly includes a valve seat body, with a gap between the outer circumferential surface of the valve seat body and the inner wall of the valve body. An annular groove is formed on the outer circumferential surface of the valve seat body. An annular protrusion with a circular arc cross-section is located on the inner wall of the valve body, fitting within the annular groove to form a fit. The annular protrusion and the bottom of the annular groove are in close line contact. This structure allows the valve seat body to achieve a slight angular deflection around the annular protrusion, thus providing the ability to float and twist. It compensates for the off-axis deformation of the sealing element, ensuring that the sealing slopes always maintain uniform contact, effectively reducing or eliminating wedge-shaped gaps between the sealing slopes, and improving sealing reliability. Simultaneously, the small gap between the outer circumferential surface of the valve seat body and the inner wall of the valve body provides the necessary space for the valve seat to twist during small radial and axial displacements.

Description

Technical Field

[0001] This utility model relates to the field of butterfly valve technology, and in particular to a floating hard-seal butterfly valve. Background Technology

[0002] In existing hard-seal butterfly valves, the valve seat is typically fixed to the valve body wall or allows for slight axial movement along the valve body using pre-tensioning components such as springs. This floating design can compensate for axial position changes in the sealing pair caused by thermal expansion or wear, helping to maintain the fit of the sealing bevel. However, for angular deformation of the sealing element, especially deformation modes where the entire sealing element undergoes off-axis torsion, the aforementioned valve seat structure, which only has axial translational freedom, is difficult to effectively follow and compensate for.

[0003] Specifically, the seals on the butterfly plate are annular in shape. In large-size butterfly valves, due to their relatively low rigidity, the seals are prone to axial torsional deformation under the influence of factors such as uneven medium pressure, temperature gradients, residual stress generated during processing, or manufacturing deviations. This deformation causes the seal to no longer remain in an ideal plane, resulting in a local wedge-shaped gap between its sealing slope and the valve seat's sealing slope, leading to loss of effective contact and ultimately leakage. Traditional rigid fixed valve seats or valve seats that can only float axially are inadequate for this type of axial torsion and the resulting sealing failure. Even if the valve seat as a whole can move axially, it cannot automatically deflect to fit the angled seal, resulting in severely insufficient sealing reliability. Utility Model Content

[0004] The purpose of this invention is to address the sealing problem caused by off-axis deformation. This invention provides a floating hard-seal butterfly valve that can adapt to the off-axis torsional deformation of the sealing element, thereby reducing the gap of the sealing bevel and improving the sealing performance.

[0005] The technical solution of this utility model includes a valve seat assembly, a valve body, a butterfly plate, and a pressure ring. The butterfly plate is provided with a sealing element. The valve seat assembly and the pressure ring are respectively installed on the inner wall of the valve body. The valve seat assembly and the sealing element are in contact through corresponding sealing bevels to achieve a sealing fit. The pressure ring presses against the valve seat assembly to limit the valve seat assembly. The valve seat assembly includes a valve seat body. There is a gap between the outer peripheral surface of the valve seat body and the inner wall of the valve body, and an annular groove is formed on the outer peripheral surface of the valve seat body. The inner wall of the valve body has an annular protrusion with a circular arc cross-section. The annular protrusion is placed in the annular groove to form a fit. The annular protrusion and the bottom of the annular groove are in close contact to form a line contact.

[0006] By adopting the above technical solution, this structure enables the valve seat body to achieve a slight angular deflection around the annular protrusion, thus possessing the ability to float and twist. When the seal on the butterfly plate undergoes off-axis torsional deformation due to medium pressure or material factors, the valve seat body can actively follow the deformation of the seal and twist synchronously under the deflection torque generated by the uneven contact stress of the sealing slope, thereby compensating for the off-axis deformation of the seal and ensuring that the sealing slope always maintains uniform contact. This effectively reduces or eliminates the wedge gap between the sealing slopes and improves sealing reliability. At the same time, the small gap between the outer circumferential surface of the valve seat body and the inner wall of the valve body provides the necessary space for the twisting of the valve seat for small radial and axial displacements. The overall design does not require complex additional mechanisms; the torsion floating compensation function can be achieved simply by improving the structure of the valve body and valve seat body, resulting in low manufacturing cost and low failure rate.

[0007] In one possible design, the annular groove is larger than the annular protrusion, so that there is a gap between the annular protrusion and the groove sidewall during pre-tightening.

[0008] With the above design, this gap provides the necessary space for the angular deflection of the valve seat body, avoiding interference or rigid contact between the groove sidewall and the annular protrusion when the valve seat is twisted, thus ensuring the smooth implementation of the floating twisting mechanism. At the same time, this gap exists in the pre-tightened assembly state and does not affect the tight support between the annular protrusion and the bottom of the groove under normal working conditions.

[0009] In one possible design, spring-loaded components are installed at both ends of the valve seat body along its axial direction. One spring-loaded component abuts against the axial end face of the valve seat body between the valve seat body and the step on the inner wall of the valve body, while the other spring-loaded component abuts against the axial end face of the valve seat body between the pressure ring and the pressure ring.

[0010] With the above design, the spring-loaded component applies an axial elastic preload to the valve seat body. On the one hand, it maintains stable line contact between the annular protrusion and the bottom of the annular groove, preventing detachment due to fluid impact or vibration. On the other hand, the elastic support does not lock the angular deflection degree of freedom of the valve seat. While providing the necessary axial constraint, it still allows the valve seat body to undergo the required small torsional deformation, thus balancing support stability and floating sensitivity.

[0011] In one possible design, several screws are screwed into the pressure ring, with the tail ends of the screws abutting against the spring-loaded component.

[0012] With the above design, the compression amount and preload of the spring-loaded component are adjustable by the screw tail end screwed onto the pressure ring, eliminating the need to disassemble the pressure ring and valve seat assembly, making on-site debugging and maintenance very convenient. Multiple screws are evenly arranged along the circumference, allowing for individual adjustment of the preload at each position, resulting in a more uniform preload on the valve seat body. In addition, the clamping force can be flexibly adjusted according to different operating conditions (such as medium pressure and temperature) or the wear state of the sealing pair, ensuring that the valve seat floating mechanism is always in good working condition, facilitating on-site maintenance and performance optimization, and extending the valve's service life.

[0013] In one possible design, the spring-loaded component is a disc spring.

[0014] With the above design, the disc spring has the characteristics of high stiffness, small deformation, adjustable load characteristics and suitability for occasions with limited axial space. It can provide stable and reliable axial preload with a compact structure and is not easy to loosen under long-term use. It is very suitable for the valve seat floating support requirements in this solution and also meets the requirements of the sharp corner of the screw end.

[0015] In one possible design, the annular protrusion is a separate annular component that is detachably fixed to the inner wall of the valve body.

[0016] By adopting the above design, the annular protrusion is transformed from the integral molding structure of the valve body into an independent and detachable annular component. This solves the assembly interference problem caused by the integral annular protrusion, which prevents the valve seat body from passing over the protrusion and being installed into the valve body. This makes the floating valve seat structure technically feasible. When the annular protrusion is damaged due to long-term fretting wear or media erosion, only the annular component needs to be replaced. There is no need to repair or scrap the entire valve body, which greatly reduces the maintenance cost throughout the entire life cycle.

[0017] In one possible design, the cross-sectional shape of the annular groove is rectangular, and the cross-sectional shape of the annular protrusion is hemispherical.

[0018] With the above design, the rectangular annular groove is easy to process, and its bottom plane forms point / line contact with the hemispherical protrusion. The contact geometry is clear, the kinematic pair relationship is clear, the processing technology is good, and it is conducive to ensuring contact accuracy and stable realization of floating torsion function. At the same time, the rectangular groove provides an interference-free side wall space for the valve seat angular deflection.

[0019] In one possible design, two sets of sealing rings are also installed on the outer circumferential surface of the valve seat body. These two sets of sealing rings are located on both sides of the annular groove and are pressed and sealed against the inner wall of the valve body.

[0020] With the above design, the sealing ring constructs a double axial bypass seal, which effectively blocks the possibility of the medium leaking from the upstream side to the downstream side through the gap on the outer periphery of the valve seat, and transforms the floating gap into a reliable sealing cavity. While ensuring the floating function of the valve seat, the overall sealing performance of the valve is not sacrificed as much as possible.

[0021] In one possible design, the sealing ring is an O-ring.

[0022] The above design, using O-rings, features low cost, simple installation grooves, and reliable static sealing performance, effectively meeting the auxiliary sealing requirements of the valve seat circumference under normal temperature and general temperature and pressure conditions.

[0023] In one possible design, the sealing ring is a U-shaped sealing ring located at the corner of the valve seat body, with the opening of the sealing ring axially facing outwards.

[0024] With the above design, the U-shaped sealing ring is a self-tightening seal. The higher the medium pressure, the wider the sealing lip opening opens under pressure, and the tighter it can fit against the inner wall of the valve body, achieving a sealing enhancement effect with increasing pressure. It is particularly suitable for harsh working conditions with high pressure or large pressure fluctuations, and can still maintain good following sealing ability when the valve seat undergoes slight deflection or twisting. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of the entire utility model;

[0026] Figure 2 This utility model Figure 1 A magnified view of a section at point A in the middle;

[0027] Figure 3 This is a partially enlarged view of another embodiment of the present invention;

[0028] Figure 4 This is a magnified view of a portion of the structure during the twisting process of this invention.

[0029] Among them, 1. Valve body; 2. Butterfly plate; 3. Pressure ring; 4. Valve seat body; 5. Clearance; 6. Disc spring; 7. Screw; 8. Sealing ring; 11. Annular protrusion; 12. Step; 21. Seal; 41. Annular groove. Detailed Implementation

[0030] like Figures 1 to 4The floating hard-seal butterfly valve shown includes a valve seat assembly, a valve body 1, a butterfly plate 2, and a pressure ring 3. A ring-shaped sealing element 21 is fixedly mounted on the butterfly plate 2, and the outer periphery of the sealing element 21 is machined with a sealing bevel. The valve seat assembly and the pressure ring 3 are respectively installed on the inner wall of the valve body 1. The valve seat assembly and the sealing element 21 contact each other through their respective sealing bevels to form a hard seal pair, achieving a sealing fit when the butterfly valve is closed. The pressure ring 3 presses against the valve seat assembly to provide axial restraint for the valve seat assembly. The valve seat assembly includes a valve seat body 4, with a gap 5 between the outer peripheral surface of the valve seat body 4 and the inner wall of the valve body 1. This gap 5 provides the necessary space for the radial floating and angular deflection of the valve seat body 4. An annular groove 41 is formed on the outer peripheral surface of the valve seat body 4. Correspondingly, an annular protrusion 11 protruding towards the center is provided on the inner wall of the valve body 1. The cross-sectional shape of the annular protrusion 11 is arc-shaped, preferably hemispherical. An annular protrusion 11 extends into and rests within the annular groove 41. The arc-shaped apex of the annular protrusion 11 is in close contact with the bottom of the annular groove 41, thus forming a continuous line contact in the circumferential direction. This line contact serves as both the support axis of the valve seat body 4 and provides a certain degree of axial sealing. When the medium pressure is established before the sealing pair, this line contact can block the direct axial path of the medium between the outer circumferential surface of the valve seat body and the inner wall of the valve body. Combined with the sealing ring, which will be mentioned later, this enhances the overall anti-leakage capability.

[0031] To ensure that the valve seat body 4 has a sensitive floating torsion response capability, the size of the annular groove 41 is larger than that of the annular protrusion 11. This ensures that, in the initial state after assembly pre-tightening, there is a sufficient gap between the annular protrusion 11 and the groove sidewall of the annular groove 41 in the axial direction of the valve seat body 4. This gap eliminates the motion interference between the groove sidewall and the protrusion when the valve seat body undergoes a slight angular deflection, ensuring that the torsion action is free from jamming.

[0032] The annular protrusion 11 is not directly integrally formed on the inner wall of the valve body 1, but is composed of an independent annular component, which is detachably fixed to the inner wall of the valve body 1. The cross-section of the annular protrusion 11 is preferably circular, and correspondingly, the bottom of the annular groove 41 can be formed into a matching arc-shaped surface or rectangle to further optimize the line contact. To accommodate the annular component, an annular mounting groove is provided on the inner wall of the valve body 1. The cross-sectional shape of this mounting groove is preferably a hemispherical cross-section groove that matches the circular protrusion, allowing the annular component to achieve accurate positioning and stable support after insertion. The annular component can adopt a split-combination structure, for example, by joining two semi-circular segments to form a complete annulus, or by forming an open ring with a single cut, giving the annular component a certain radial elastic contraction capability. During assembly, the valve seat body 4 is first axially inserted from one end of the valve body 1, aligning its outer circumferential annular groove 41 with the mounting groove on the inner wall of the valve body 1 axially. Next, the segmented annular components are placed into the mounting groove piece by piece, or the radial elasticity of the open annular component is used to compress it radially to reduce its outer profile. It then passes through the gap between the valve seat body 4 and the valve body 1 and is placed into the mounting groove. After release, the annular component expands due to its own elasticity and embeds itself into the mounting groove for positioning. At this point, the annular protrusion 11 extends radially into the annular groove 41, and its arc-shaped apex is in close contact with the bottom of the annular groove 41, forming a continuous line contact support. Afterward, the disc springs 6 on the axially outer side of the valve seat body 4 are installed sequentially, and then the three-part pressure ring 3 is installed and screwed in with screws 7, completing the final fixing and preload adjustment of the valve seat assembly.

[0033] To achieve flexible and adjustable axial positioning, spring-loaded components are installed at both ends of the valve seat body 4 along its axial direction. In this embodiment, the spring-loaded components are preferably disc springs 6. One disc spring 6 abuts against the first axial end face of the valve seat body 4 and the step 12 on the inner wall of the valve body, while the other disc spring 6 abuts against the second axial end face of the valve seat body 4 and the pressure ring 3. The advantage of using disc springs is that they not only have high rigidity and occupy little space, making them particularly suitable for butterfly valves with limited internal space, but also the force-bearing end face of the disc spring is approximately planar. This structural feature meets the adjustment requirements: several screws 7 are circumferentially screwed into the pressure ring 3. The tail end of the screw 7 can be made into a conical tip or a ball head, and the tip or ball head abuts against the end face of the disc spring 6. The flat end face of the disc spring 6 provides a stable, non-slipping force application platform for the sharp corner of the screw 7 to abut. The resulting point contact abutment allows the pressure ring 3 to exhibit slight kinetic movement relative to the disc spring 6, preventing additional warping torque on the valve seat body 4 due to the pressure of the screw 7, thus ensuring the accuracy of the preload adjustment. Operators can easily adjust the preload of the pressure ring on the valve seat assembly by turning each screw 7 to adapt to different pressure levels or compensate for minor stress relaxation after long-term operation.

[0034] To further ensure the sealing integrity of the floating gap area, two sets of sealing rings 8 are also installed on the outer circumferential surface of the valve seat body 4. These two sets of sealing rings 8 are respectively located on both axial sides of the annular groove 41 and are pressed and sealed against the inner wall of the valve body 1. In this embodiment, as... Figure 2 As shown, sealing ring 8 can be an O-ring to reduce manufacturing costs and is suitable for working conditions with normal temperature, normal pressure or relatively relaxed requirements for auxiliary sealing.

[0035] Another implementation method is: such as Figure 3 , Figure 4 As shown, as an optional equivalent replacement, the sealing ring 8 is a U-shaped sealing ring, which is located at the corresponding corner of the valve seat body 4, with its opening facing outward axially. This arrangement is a self-tightening seal; the higher the medium pressure, the more the sealing lip is stretched and pressed tightly against the inner wall of the valve body 1, and the sealing effect increases with increasing pressure. Even when the valve seat body 4 undergoes slight torsional deformation, the U-shaped sealing ring can maintain a reliable seal by relying on its own elasticity and lip following ability, always remaining tightly against the inner wall of the valve body.

[0036] The working principle and process of this application are as follows: When the butterfly valve is closed, the butterfly plate 2 rotates to the sealing position, and the sealing element 21 on it contacts the valve seat body 4 through the sealing inclined surface. The initial preload is applied by the disc spring 6 and the pressure ring 3 together, and the annular protrusion 11 contacts the bottom line of the annular groove 41, so that the valve seat body is in a stable centering state.

[0037] When a pressure difference exists within the pipeline, or due to factors such as temperature changes or material stress release, the large-sized seal 21 undergoes off-axis torsional deformation, meaning its sealing slope is no longer locally coplanar, the contact stress between the sealing pairs will exhibit a non-uniform distribution. At this time, the deformed and raised area of ​​the seal 21 attempts to separate from the valve seat body, while its opposite side is more tightly compressed. This unbalanced contact stress generates a net torque around the line contact support point of the annular protrusion 11.

[0038] Under this torque, the valve seat body 4 uses the line contact between the annular groove 41 and the bottom of the annular protrusion 11 as a floating fulcrum, generating a slight torsional deformation that adapts to the deformation direction of the seal 21. As the angle of the valve seat body 4 follows the deflection, the sealing bevels that were originally about to separate come closer and press together again, thereby effectively eliminating the wedge gap and preventing leakage. During the torsion of the valve seat body 4, the gap 5 between the side wall of the annular groove 41 and the annular protrusion 11 provides movement space, while the disc springs 6 at both ends of the axial direction continuously provide elastic clamping force, maintaining the stability of the line contact and enabling the valve seat body 4 to have a reset capability. At the same time, the line contact between the annular protrusion 11 and the bottom of the groove, together with the sealing ring 8, effectively prevents the medium from leaking downstream from the outside of the valve seat body 4, ensuring the sealing reliability of the valve under all operating conditions.

Claims

1. A floating hard-seal butterfly valve, comprising a valve seat assembly, a valve body (1), a butterfly plate (2), and a pressure ring (3), wherein the butterfly plate (2) is provided with a sealing element (21), the valve seat assembly and the pressure ring (3) are respectively installed on the inner wall of the valve body (1), the valve seat assembly and the sealing element (21) are in contact with each other through corresponding sealing bevels for sealing cooperation, and the pressure ring (3) presses against the valve seat assembly to limit the valve seat assembly; characterized in that: The valve seat assembly includes a valve seat body (4), with a gap (5) between the outer peripheral surface of the valve seat body (4) and the inner wall of the valve body (1), and an annular groove (41) is provided on the outer peripheral surface of the valve seat body (4). The inner wall of the valve body (1) has an annular protrusion (11) with a circular arc cross-section. The annular protrusion (11) is placed in the annular groove (41) to form a fit, and the annular protrusion (11) and the bottom of the annular groove (41) are in close contact to form a line contact.

2. The floating hard-seal butterfly valve according to claim 1, characterized in that: The size of the annular groove (41) is larger than that of the annular protrusion (11), so that there is a gap between the annular protrusion (11) and the groove sidewall of the annular groove (41) during pre-tightening.

3. The floating hard-seal butterfly valve according to claim 1 or 2, characterized in that: The valve seat body (4) is equipped with spring-loaded components at both ends of its axial direction. One side of the spring-loaded component abuts between the axial side end face of the valve seat body (4) and the inner wall step (12) of the valve body (1), while the other side of the spring-loaded component abuts between the axial side end face of the valve seat body (4) and the pressure ring (3).

4. The floating hard-seal butterfly valve according to claim 3, characterized in that: The pressure ring (3) is screwed with several screws (7), and the tail end of the screws (7) abuts against the spring-loaded component.

5. The floating hard-seal butterfly valve according to claim 3, characterized in that: The spring-loaded component is a disc spring (6).

6. The floating hard-seal butterfly valve according to claim 1 or 2, characterized in that: The annular protrusion (11) is an independent annular component, which is detachably fixed to the inner wall of the valve body (1).

7. The floating hard-seal butterfly valve according to claim 1 or 2, characterized in that: The cross-sectional shape of the annular groove (41) is rectangular, and the cross-sectional shape of the annular protrusion (11) is hemispherical.

8. The floating hard-seal butterfly valve according to claim 1 or 2, characterized in that: Two sets of sealing rings (8) are also installed on the outer circumferential surface of the valve seat body (4). The two sets of sealing rings (8) are respectively located on both sides of the annular groove (41) and are squeezed and sealed with the inner wall of the valve body (1).

9. The floating hard-seal butterfly valve according to claim 8, characterized in that: The sealing ring (8) is an O-ring (8).

10. The floating hard-seal butterfly valve according to claim 8, characterized in that: The sealing ring (8) is a U-shaped sealing ring (8), which is located at the corner of the valve seat body (4), and the opening of the sealing ring (8) is arranged axially outward.

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