Hard sealing butterfly valve with bidirectional sealing structure

Abstract

This invention relates to a hard-seal butterfly valve with a bidirectional sealing structure. The invention includes a valve body; a valve plate assembly including a connected valve plate and valve stem, the valve plate rotating within the valve body via the valve stem; a valve seat assembly disposed within the valve body, including a valve seat pressure ring, a valve seat gasket, a beveled sealing surface valve seat, and a triple-eccentric conical valve seat that abut against each other in sequence, with a conical sealing ring on the valve plate; a valve plate pressure ring connected to the valve plate; and an elastic sealing ring pressed and fixed to the valve plate by the valve plate pressure ring, the elastic sealing ring having an elastic deformation portion suitable for contacting the beveled sealing surface of the beveled sealing surface valve seat and the valve plate, with a groove on the side of the elastic deformation portion facing away from the valve stem, forming a medium introduction channel between the flow-guiding bevel of the valve plate pressure ring and the beveled sealing surface valve seat and valve seat gasket. This invention improves the valve's reverse sealing capability, achieving bidirectional sealing under both forward and reverse medium pressures, and solves the problem of poor sealing performance of traditional butterfly valves under reverse pressure.

Description

Technical Field

[0001] This invention relates to the field of butterfly valve technology, and in particular to a hard-seal butterfly valve with a bidirectional sealing structure. Background Technology

[0002] A butterfly valve is a type of valve that controls the flow and regulation of fluids by rotating a valve stem to drive a valve plate to rotate within the valve body at a speed of 0° to 90°. With its advantages of rapid opening and closing, low opening and closing torque, low fluid resistance, small size, light weight, and excellent regulating performance, the butterfly valve is widely used in chemical, metallurgical, energy, mining, urban water supply and drainage, and other fields. Its simple structure and convenient installation and maintenance make it an indispensable and important piece of equipment in fluid control systems.

[0003] The sealing design of hard-seal butterfly valves performs best in forward sealing (medium flows in from the valve stem side). Its sealing mechanism achieves a wedge-shaped self-tightening effect through a triple eccentric conical ring and valve seat, and the higher the medium pressure, the tighter the seal. In reverse sealing (medium flows in from the valve seat side), due to the fit clearance between the valve stem and the bushing, and the bending deformation of the valve stem caused by the medium force, the sealing ring is prone to detach from the valve seat due to the medium pressure, making it difficult to meet the leakage level requirements. Summary of the Invention

[0004] Therefore, this invention provides a hard-seal butterfly valve with a bidirectional sealing structure, which improves the valve's reverse sealing capability, achieves bidirectional sealing under both forward and reverse medium pressure, and solves the problem of poor sealing performance of traditional butterfly valves under reverse pressure.

[0005] To solve the above technical problems, the present invention provides a hard-seal butterfly valve with a bidirectional sealing structure, comprising: Valve body; A valve plate assembly includes a connected valve plate and a valve stem, the valve plate rotating within a valve body via the valve stem; A valve seat assembly, disposed within the valve body, includes a valve seat pressure ring, a valve seat gasket, a slanted sealing surface valve seat, and a triple eccentric conical valve seat that abut against each other in sequence. A conical sealing ring suitable for contacting the triple eccentric conical valve seat through a conical surface is provided on the valve plate. A valve plate pressure ring is connected to the valve plate; An elastic sealing ring is pressed and fixed on the valve plate by the valve plate pressure ring. The elastic sealing ring has an elastic deformation portion adapted to contact the inclined sealing surface of the inclined sealing surface valve seat and the valve plate. The elastic deformation portion has a groove on the side facing away from the valve stem. The outer peripheral end of the valve plate pressure ring is provided with a flow guiding slope. The flow guiding slope forms a medium introduction channel between the inner ring plane of the valve seat gasket and the inclined sealing surface of the inclined sealing surface valve seat. The radial dimension of the medium introduction channel is constricted towards the groove. The groove faces the end of the medium introduction channel. The medium enters through the medium introduction channel and contacts the groove. When the medium flows in from the valve seat assembly, the groove can undergo radial deformation under the pressure of the medium, so that the elastic deformation part is tightly fitted with the oblique sealing surface valve seat and the valve plate to form a reverse seal. When the medium pressure flows in from the valve stem direction, the medium pressure acts on the valve plate and pushes the conical sealing ring to fit tightly against the triple eccentric conical valve seat, forming a positive seal.

[0006] In one embodiment of the present invention, the elastic sealing ring further has an annular mounting portion connected to the elastic deformation portion, and a first annular step is provided at one end of the valve plate facing the valve plate pressure ring. The annular mounting portion is sleeved on the outer peripheral end of the first annular step and is pressed against the step surface of the first annular step by the valve plate pressure ring.

[0007] In one embodiment of the present invention, the axial end faces of the annular mounting portion are provided with serrated grooves.

[0008] In one embodiment of the present invention, the valve plate is further provided with a second annular step that connects with the first annular step. The valve plate pressure ring, the second annular step, and the triple eccentric conical valve seat form a receiving area for accommodating the elastic deformation part. The elastic deformation part contacts the step surface of the second annular step.

[0009] In one embodiment of the present invention, the slot is U-shaped or open arc-shaped.

[0010] In one embodiment of the present invention, the valve plate and the conical sealing ring are integrally formed.

[0011] In one embodiment of the present invention, a pin is connected between the valve stem and the valve plate.

[0012] In one embodiment of the present invention, the upper and lower shaft holes of the valve body and the two ends of the valve stem are respectively provided with a first bushing and a second bushing. The valve stem is fitted with the first bushing and the second bushing through clearance. The first bushing and the second bushing each extend axially to the end near the valve plate.

[0013] In one embodiment of the present invention, a winding gasket is provided between the mounting step on the inner wall of the valve body and the triple eccentric conical valve seat, and between the triple eccentric conical valve seat and the oblique sealing surface valve seat.

[0014] In one embodiment of the present invention, a bottom cover is installed at the lower end of the valve body.

[0015] The technical solution of the present invention has the following advantages over the prior art: This invention discloses a hard-seal butterfly valve with a bidirectional sealing structure. A conical sealing ring is installed on the valve plate, forming a main sealing pair with a triple-eccentric conical valve seat during forward sealing, ensuring forward sealing performance. When medium pressure is applied from the valve seat direction, the groove of the elastic sealing ring is subjected to the medium pressure, causing radial deformation of the elastic sealing ring. This deformation effectively compensates for the slight displacement caused by the sealing ring disengaging from the valve seat due to medium pressure. The radial deformation of the elastic sealing ring tightly fits the oblique sealing surface of the valve seat, ensuring reverse sealing performance. The elastic compensation design enhances the reverse sealing performance. Through the synergistic effect of the forward conical seal and the reverse elastic seal, the valve can seal in both forward and reverse medium flow directions, solving the problem of poor sealing performance of traditional butterfly valves under reverse pressure.

[0016] This invention utilizes a media inlet channel with a radial dimension that gradually decreases from the outside in. As the medium flows along this channel, its velocity and kinetic energy increase, leading to increased dynamic pressure at the channel outlet. This results in a higher applied pressure near the inlet, increasing the local static pressure at the inlet. Since the inlet faces the end of the media inlet channel, the medium acts directly on it upon entry, preventing energy dispersion. The pressure distribution of the medium acts on the inner wall of the inlet, allowing the elastic deformation portion to undergo more significant radial elastic deformation. This deformation portion is then pushed by the medium against the inclined sealing surface valve seat and the valve plate, enhancing sealing performance. Furthermore, this media inlet channel is formed within the valve plate pressure ring, valve seat gasket, and inclined sealing surface valve seat, and can be achieved through simple inclined surface machining, requiring no additional configuration, resulting in simple manufacturing and low cost.

[0017] The elastic sealing ring of this invention consists of a U-shaped or open arc-shaped elastic deformation portion and an annular mounting portion with serrated grooves on both end faces. The elastic sealing ring is made of stainless steel or nickel-based high-temperature alloy, with a thickness of 2-3 mm. It can be formed through precision machining processes such as stamping and turning. The elastic sealing ring can achieve high-precision fit with the oblique sealing surface of the valve seat, ensuring uniform contact and stable sealing performance. The overall thickness of the elastic sealing ring remains consistent, ensuring uniform elastic distribution and balanced stress transmission under pressure, thus balancing good elastic recovery capability and structural strength. The serrated grooves on both end faces of the annular mounting portion, in addition to enhancing assembly friction, can also form a local labyrinth seal structure, effectively blocking media leakage paths and further improving the valve's sealing reliability.

[0018] This invention employs an axially extended first and second bushing design, extending the bushing ends close to the valve plate area. This significantly shortens the fulcrum distance of the valve stem, effectively suppressing bending deformation of the valve stem under stress. This design not only improves the stability of the valve stem support but also ensures more precise coaxiality between the valve stem and the valve plate, avoiding uneven contact of the sealing pair caused by eccentricity. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of the hard-seal butterfly valve with a bidirectional sealing structure according to the present invention.

[0021] Figure 2 For along Figure 1 A sectional view along the XX direction.

[0022] Figure 3 for Figure 2 Enlarged view of the structure at point Z.

[0023] Explanation of reference numerals in the instruction manual: 1. Valve body; 2. Valve plate; 21. First annular step; 22. Second annular step; 23. Receiving area; 2a. Conical sealing ring; 2b. Elastic sealing ring; 2c. Valve plate pressure ring; 211. Elastic deformation part; 212. Groove; 213. Annular mounting part; 214. Serrated groove; 215. Guide slope; 3a. Triple eccentric cone valve seat; 3b. Oblique sealing surface valve seat; 31b. Oblique sealing surface; 31. Medium inlet channel; 4. Valve stem; 5. Valve seat gasket; 51. Inner ring plane; 6. Valve seat pressure ring; 8. Pins; 9. Bottom cover; 10a, First bushing; 10b, Second bushing; 11. Stretch wrap. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0025] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0026] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0028] Reference Figures 1 to 3 As shown, a hard-seal butterfly valve with a bidirectional sealing structure according to the present invention, specifically a triple-eccentric butterfly valve, includes: Valve body 1; A valve plate assembly includes a connected valve plate 2 and a valve stem 4, wherein the valve plate 2 rotates within the valve body 1 under the drive of the valve stem 4; The valve seat assembly is disposed within the valve body 1 and includes a valve seat pressure ring 6, a valve seat gasket 5, a valve seat 3b with an oblique sealing surface, and a triple eccentric conical valve seat 3a that abut against each other in sequence. The valve plate 2 is provided with a conical sealing ring 2a that is suitable for contacting the triple eccentric conical valve seat 3a through the conical surface. Valve plate pressure ring 2c is connected to the valve plate 2; An elastic sealing ring 2b is pressed and fixed on the valve plate 2 by the valve plate pressure ring 2c. The elastic sealing ring 2b has an elastic deformation portion 211 adapted to contact the inclined sealing surface 31b of the inclined sealing surface valve seat 3b and the valve plate 2. The elastic deformation portion 211 has a groove 212 on the side facing away from the valve stem 4. The outer peripheral end of the valve plate pressure ring 2c is provided with a flow guiding slope 215. The flow guiding slope 215 forms a medium introduction channel 31 between the inner ring plane 51 of the valve seat pad 5 and the inclined sealing surface 31b of the inclined sealing surface valve seat 3b. The radial dimension of the medium introduction channel 31 is tapered towards the groove 212. The groove 212 faces the end of the medium introduction channel 31. The medium enters through the medium introduction channel 31 and contacts the groove 212. When the medium flows in from the valve seat assembly, the groove 212 can undergo radial deformation under the pressure of the medium, so that the elastic deformation part 211 is tightly fitted with the oblique sealing surface valve seat 3b and the valve plate 2 (at the same time, the elastic deformation part 211 will generate a force that makes the oblique sealing surface valve seat 3b close to the valve seat pad 5), forming a reverse seal. When the medium pressure flows in from the valve stem 4, the medium pressure acts on the valve plate 2 and pushes the conical sealing ring 2a to press tightly against the triple eccentric conical valve seat 3a (so that the conical sealing ring 2a generates a force that makes the triple eccentric conical valve seat 3a and the oblique sealing surface valve seat 3b close to the valve seat pad 5), forming a positive seal.

[0029] Through the coordinated operation of the conical sealing ring 2a, the elastic sealing ring 2b, the triple eccentric conical valve seat 3a, and the oblique sealing surface valve seat 3b, reliable sealing can be achieved when the medium flows in from both the forward and reverse directions.

[0030] It should be noted that the elastic sealing ring 2b is made of an elastic material (such as alloy or stainless steel) and has an elastic deformation part 211, which can generate radial elastic deformation under the action of reverse medium pressure to compensate for the small displacement caused by the gap or deformation of the valve stem 4. A groove 212 is provided on its side opposite to the valve stem 4 and cooperates with the medium inlet channel 31, so that the medium pressure can directly act on the deformation part of the sealing ring; the greater the pressure, the tighter the seal. This structure significantly improves the reverse sealing capability.

[0031] Furthermore, the medium inlet channel 31 is a slot 212 that guides the reverse fluid medium into the elastic sealing ring 2b. Its radial dimension gradually decreases from the outside to the inside, forming a constricted flow channel. When the medium flows along the medium inlet channel 31, according to Bernoulli's principle, the medium velocity increases and the kinetic energy increases within the medium inlet channel 31, resulting in increased dynamic pressure in the outlet region of the medium inlet channel 31. This causes the medium to be converted into a higher acting pressure near the slot 212, increasing the local static pressure at the acting slot 212. Since the slot 212 faces the end of the medium inlet channel 31, the medium directly acts on the slot 212 after entering it, avoiding energy dispersion. Through the medium pressure distribution acting on the inner wall of the slot 212, the elastic deformation part 211 can more fully generate radial elastic deformation. Thus, the elastic deformation part 211 is pushed by the medium towards the inclined sealing surface valve seat 3b and the valve plate 2, thereby enhancing the sealing performance. If the radial dimension of the medium inlet channel 31 is constant or gradually expands from the outside to the inside, the fluid is prone to forming a backflow zone or local turbulence before entering the slot 212, resulting in uneven pressure transmission. Therefore, the constricted flow channel design can maintain smooth fluid guidance and improve the efficiency of medium pressure utilization.

[0032] Furthermore, the medium introduction channel 31 is formed on the valve plate pressure ring 2c, the valve seat gasket 5, and the oblique sealing surface valve seat 3b. It can be achieved through simple oblique surface machining without additional settings, making it simple to manufacture and low in cost.

[0033] In one embodiment, refer to Figure 3 As shown, the elastic sealing ring 2b also has an annular mounting portion 213 connected to the elastic deformation portion 211. The valve plate 2 has a first annular step 21 at one end facing the valve plate pressure ring 2c. The annular mounting portion 213 is sleeved on the outer peripheral end of the first annular step 21 and is pressed against the step surface of the first annular step 21 by the valve plate pressure ring 2c.

[0034] In one embodiment, refer to Figure 3 As shown, the annular mounting portion 213 has serrated grooves 214 on both axial end faces. During the installation of the elastic sealing ring 2b, the serrated grooves 214 can significantly increase the friction between the annular mounting portion 213 and the first annular step 21 and the valve plate pressure ring 2c, thereby effectively preventing the elastic sealing ring 2b from axially slipping or shifting due to vibration and temperature changes during valve operation, and improving the installation stability and positioning reliability of the elastic sealing ring 2b.

[0035] It should be noted that the elastic sealing ring 2b consists of an elastically deformable part in the shape of a U-shape or an open arc and an annular mounting part 213 with serrated grooves 214 on both ends. The elastic sealing ring 2b is made of stainless steel or nickel-based high-temperature alloy material, with a thickness of 2-3 mm, which can be appropriately adjusted according to the valve diameter and pressure rating.

[0036] The elastic sealing ring 2b is formed by precision machining processes such as stamping and turning. Its shape tolerance and dimensional tolerance must be strictly controlled to ensure that the elastic sealing ring 2b can achieve high-precision fit with the oblique sealing surface 31b of the oblique sealing surface valve seat 3b, and ensure uniform contact and stable sealing performance of the sealing surface.

[0037] The overall thickness of the elastic sealing ring 2b remains consistent, ensuring uniform elastic distribution and balanced stress transmission under pressure, thus balancing good elastic recovery capability with structural strength.

[0038] In addition to enhancing assembly friction, the serrated grooves 214 on both ends of the annular mounting part 213 can also form a local labyrinth seal structure, which can effectively block the leakage path of the medium and further improve the sealing reliability of the valve.

[0039] In one embodiment, refer to Figure 3 As shown, the valve plate 2 is also provided with a second annular step 22 that connects with the first annular step 21. The valve plate pressure ring 2c, the second annular step 22 and the triple eccentric conical valve seat 3a form a receiving area 23 for accommodating the elastic deformation part 211. The elastic deformation part 211 is in contact with the step surface of the second annular step 22.

[0040] In one embodiment, refer to Figure 3 As shown, the groove 212 is U-shaped or open arc-shaped. The U-shaped (or open arc-shaped) groove 212 can provide a larger elastic deformation and a more uniform stress distribution, so that the sealing ring can form a stable radial deformation when under pressure. It can fully fit the sealing surface and is not prone to stress concentration or cracks, thus improving the reliability of reverse sealing.

[0041] In one embodiment, refer to Figure 1 As shown, a pin 8 connects the valve stem 4 to the valve plate 2; a first bushing 10a and a second bushing 10b are respectively provided on the upper and lower shaft holes of the valve body 1 and at both ends of the valve stem 4, and the valve stem 4 is fitted with the first bushing 10b and the second bushing 10b through clearance; a spiral wound gasket 11 is provided between the mounting step on the inner wall of the valve body 1 and the triple eccentric conical valve seat 3a, and between the triple eccentric conical valve seat 3a and the oblique sealing surface valve seat 3b; a bottom cover 9 is installed at the lower end of the valve body 1.

[0042] Specifically, refer to Figure 1As shown, the first bushing 10a and the second bushing 10b each extend axially to near the end of the valve plate 2. This axial extension of the bushing 10b reduces the gap between the first bushing 10a and the second bushing 10b and the valve plate 2 to near zero, shortening the fulcrum distance of the valve stem 4, reducing bending deformation of the valve stem 4 under stress, and ensuring stability under both forward and reverse pressure. Both the first bushing 10a and the second bushing 10b, along with the valve stem 4, are precision-machined from forged stainless steel, possessing high rigidity and effectively preventing deformation of the valve stem 4, thus reducing the impact of deformation caused by the medium force on the sealing performance.

[0043] It should be noted that during installation, firstly, the first bushing 10a and the second bushing 10b are respectively installed in the upper and lower shaft holes of the valve body 1. Then, the valve plate 2 is correctly placed in the middle of the valve body 1, and the shaft hole of the valve body 1 is aligned with the shaft hole of the valve plate 2. After that, the valve stem 4 is installed, and the valve stem 4 is connected to the valve plate 2 by the pin 8 to realize the transmission.

[0044] Subsequently, the elastic sealing ring 2b is fitted onto the first annular step 21 of the valve plate 2, and the valve plate pressure ring 2c is placed on top of it and tightened with hexagonal head screws to reliably press the elastic sealing ring 2b onto the valve plate 2.

[0045] Next, place the valve body 1 and valve plate 2 horizontally, and then assemble the spiral wound gasket 11, triple eccentric conical valve seat 3a, spiral wound gasket 11, oblique sealing surface valve seat 3b, valve seat gasket 5, and valve seat pressure ring 6 onto the valve body 1 in sequence. Tighten the screws to press the triple eccentric conical valve seat 3a and the oblique sealing surface valve seat 3b together, ensuring a reliable sealing fit with the conical sealing ring 2a and the elastic sealing ring 2b, respectively. Finally, fix the bottom cover 9 to the lower end of the valve body 1 with bolts to complete the overall assembly.

[0046] Furthermore, the conical sealing ring 2a is integrally formed with the valve plate 2, and the two are precision-machined to form a high-precision conical sealing structure. This avoids the machining errors and assembly misalignments caused by threaded connections or interference fits, simplifies manufacturing and maintenance processes, and significantly improves the contact accuracy and long-term stability of the sealing pairs. An appropriate preload torque is applied between the conical sealing ring 2a and the triple-eccentric conical valve seat 3a to generate uniform contact stress on their contact surfaces. A certain offset angle is designed on the contact surfaces, resulting in elastic deformation under contact stress, forming a slight wedge effect, and achieving a reliable self-tightening seal.

[0047] Working principle: In reverse sealing mode, due to the clearance fit between the valve stem 4 and the first bushing 10a and the second bushing 10b, a small clearance exists. Medium pressure may cause a slight separation between the sealing ring and the valve seat. At this time, the groove 212 of the elastic sealing ring 2b undergoes radial elastic deformation under the medium pressure, effectively compensating for this displacement. This allows the elastic sealing ring 2b to re-tightly fit with the oblique sealing surface valve seat 3b, ensuring reverse sealing performance. The radial deformation of the elastic sealing ring 2b effectively compensates for the slight displacement caused by the sealing ring separating from the valve seat due to medium pressure, achieving a tight fit between the elastic sealing ring 2b and the oblique sealing surface valve seat 3b. The higher the pressure, the better the valve sealing effect.

[0048] In the positive sealing state, the medium pressure acts on the valve plate 2, pushing the conical sealing ring 2a, which is integral with the valve plate 2, towards the triple eccentric conical valve seat 3a. The valve seat pressure ring 6 applies axial preload to the valve seat gasket 5, the oblique sealing surface valve seat 3b, and the triple eccentric conical valve seat 3a, so that the conical sealing ring 2a and the triple eccentric conical valve seat 3a form a stable contact, thereby achieving a positive seal.

[0049] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hard-seal butterfly valve with a bidirectional sealing structure, characterized in that, include: Valve body (1); The valve plate assembly includes a connected valve plate (2) and a valve stem (4), wherein the valve plate (2) rotates within the valve body (1) by the drive of the valve stem (4); The valve seat assembly is disposed in the valve body (1) and includes a valve seat pressure ring (6), a valve seat gasket (5), an oblique sealing surface valve seat (3b), and a triple eccentric conical valve seat (3a) that abut against each other in sequence. The valve plate (2) is provided with a conical sealing ring (2a) that is suitable for contacting the triple eccentric conical valve seat (3a) through the conical surface. Valve plate pressure ring (2c) is connected to the valve plate (2); An elastic sealing ring (2b) is pressed and fixed onto the valve plate (2) by the valve plate pressure ring (2c). The elastic sealing ring (2b) has an elastic deformation portion (211) suitable for contacting the inclined sealing surface (31b) of the inclined sealing surface valve seat (3b) and the valve plate (2). The elastic deformation portion (211) has a groove (212) on the side facing away from the valve stem (4). The outer peripheral end of the valve plate pressure ring (2c) is provided with a flow guiding slope (215). A medium inlet channel (31) is formed between the flow guide slope (215), the inner ring plane (51) of the valve seat gasket (5), and the inclined sealing surface (31b) of the inclined sealing surface valve seat (3b). The radial dimension of the medium inlet channel (31) is tapered towards the slot (212). The slot (212) faces the end of the medium inlet channel (31). The medium enters through the medium inlet channel (31) and contacts the slot (212). When the medium flows in from the valve seat assembly, the groove (212) can undergo radial deformation under the pressure of the medium, so that the elastic deformation part (211) fits tightly with the oblique sealing surface valve seat (3b) and the valve plate (2) to form a reverse seal. When the medium pressure flows in from the valve stem (4), the medium pressure acts on the valve plate (2) and pushes the conical sealing ring (2a) to press against the triple eccentric conical valve seat (3a) to form a positive seal.

2. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, The elastic sealing ring (2b) also has an annular mounting portion (213) connected to the elastic deformation portion (211). The valve plate (2) has a first annular step (21) at one end facing the valve plate pressure ring (2c). The annular mounting portion (213) is sleeved on the outer peripheral end of the first annular step (21) and the annular mounting portion (213) is pressed against the step surface of the first annular step (21) by the valve plate pressure ring (2c).

3. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 2, characterized in that, The annular mounting portion (213) has serrated grooves (214) on both axial end faces.

4. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 2, characterized in that, The valve plate (2) is also provided with a second annular step (22) that connects with the first annular step (21). The valve plate pressure ring (2c), the second annular step (22) and the triple eccentric conical valve seat (3a) form a receiving area (23) for receiving the elastic deformation part (211). The elastic deformation part (211) is in contact with the step surface of the second annular step (22).

5. A hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, The slot (212) is U-shaped or open arc-shaped.

6. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, The valve plate (2) and the conical sealing ring (2a) are integrally formed.

7. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, A pin (8) connects the valve stem (4) to the valve plate (2).

8. The hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, The upper and lower shaft holes of the valve body (1) and the two ends of the valve stem (4) are respectively provided with a first bushing (10a) and a second bushing (10b). The valve stem (4) is fitted with the first bushing (10a) and the second bushing (10b) through clearance. The first bushing (10a) and the second bushing (10b) each extend axially to the end near the valve plate (2).

9. A hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, A spiral wound gasket (11) is provided between the mounting step on the inner wall of the valve body (1) and the triple eccentric conical valve seat (3a), and between the triple eccentric conical valve seat (3a) and the oblique sealing surface valve seat (3b).

10. A hard-seal butterfly valve with a bidirectional sealing structure according to claim 1, characterized in that, A bottom cover (9) is installed at the lower end of the valve body (1).

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