Elastic sealing structure of butterfly valve

Abstract

The utility model discloses an elastic sealing structure of a butterfly valve, which relates to the technical field of butterfly valves and has the functions of high-elasticity compensation capability and pre-adjustment characteristic. The hard sealing valve seat is made of an elastic metal material, the section of the hard sealing valve seat is in an m shape, a first peak part and a second peak part are in elastic contact with different positions of the outer edge of the butterfly plate respectively to form double sealing, a first valley part is supported on the inner wall of the valve body, and a second valley part and a third valley part are supported on different inner wall positions of the gland respectively; a main supporting inclined face is formed on the inner wall of the gland, and the second valley portion is connected to the main supporting inclined face in a pressed mode so that the diameter of the second valley portion can be reduced towards the center of the valve body through the main supporting inclined face when the gland is adjusted and moved forwards. Fluid leakage can be effectively prevented, sealing reliability and stability are improved, compensation can be performed to a certain degree through self elastic deformation, a good sealing effect is kept, the second valley part can be reduced towards the center direction of the valve body through the main supporting inclined surface, and therefore dynamic adjustment of sealing pre-tightening force is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of butterfly valves, in particular to an elastic sealing structure of a butterfly valve. Background Art

[0002] Butterfly valves, as a pipe connector used to cut off or regulate fluid flow, are widely used in many industrial fields such as petroleum, chemical industry, metallurgy, water supply and drainage. In order to improve the durability of the sealing structure, a solution using a metal hard-sealed valve seat has emerged in the existing technology. Usually, a weld overlay is provided on the contact surface between the valve seat and the butterfly plate to achieve sealing. However, this structure has obvious defects. The metal valve seat itself lacks elastic compensation ability. During long-term opening and closing, it is easy to produce gaps due to mechanical wear or thermal deformation, resulting in a decrease in sealing performance. On the other hand, traditional hard sealing structures generally adopt an integral valve seat design, which cannot achieve dynamic adjustment of the sealing preload. When the sealing surface is worn, the valve seat needs to be disassembled and replaced, which has high maintenance costs.

[0003] In recent years, some improvements have attempted to incorporate elastic elements into the valve seat structure. For example, Chinese invention patent publication CN115076387A, a U-shaped metal-sealed butterfly valve, proposes a U-shaped valve seat that utilizes spring force to compensate for sealing contact pressure. However, this structure is limited by the fatigue life of the spring and spatial constraints, making uniform radial compensation difficult to achieve. Furthermore, it lacks the pre-adjustment mechanism commonly associated with existing elastic compensation structures. Utility Model Content

[0004] Purpose of the present invention: In order to overcome the defects of the prior art, the present invention provides an elastic sealing structure of a butterfly valve, which has the functions of high elastic compensation capability and pre-adjustment adjustment characteristics.

[0005] The technical solution of the present utility model comprises a gland, a butterfly plate, a hard sealing valve seat and a valve body, the gland can be axially adjusted and installed in the valve body, the hard sealing valve seat is made of elastic metal material and has an "M"-shaped cross-section, the hard sealing valve seat comprises a first peak and a second peak at the inner edge position and a first valley, a second valley and a third valley at the outer edge position, the first peak is located between the first valley and the second valley, the second peak is located between the second valley and the third valley, the first peak and the second peak are elastically contacted with different positions of the outer edge of the butterfly plate to form a double-pass seal, the first valley is supported on the inner wall of the valve body, the second valley and the third valley are supported on different inner wall positions of the gland respectively; a main supporting inclined surface is formed at the inner wall of the gland, the main supporting inclined surface starts from the inner wall of the gland, and is inclined axially backward and toward the center of the valve body, the second valley is pressed onto the main supporting inclined surface so that the diameter can be reduced toward the center of the valve body through the main supporting inclined surface when the gland is adjusted and displaced forward.

[0006] Using the above technical solution, the hard-sealed valve seat is made of elastic metal material and has an "M"-shaped cross-section. The first peak and the second peak form a double-channel seal, which can more effectively prevent fluid leakage and improve the reliability and stability of the seal compared to the traditional single-channel seal. Moreover, the characteristics of the elastic metal material enable the valve seat to compensate to a certain extent through its own elastic deformation when subjected to the pressure of the butterfly plate and the wear during long-term use, thereby reducing the gap caused by wear and maintaining a good sealing effect. In addition, the setting of the main support bevel enables the second valley to shrink toward the center of the valve body through the main support bevel when the pressure cover is adjusted and shifted forward, thereby realizing dynamic adjustment of the sealing preload force and enhancing the adaptability of the sealing structure.

[0007] In one possible design, a secondary supporting inclined surface is formed on the inner wall of the pressure cover, and the secondary supporting inclined surface is inclined in the same direction as the main supporting inclined surface; an inclined boss is formed on the inner wall of the valve body, and the top surface of the inclined boss is inclined axially forward from the inner wall of the valve body and toward the center of the valve body; an adjustment gap is reserved between the inclined boss and the pressure cover for the pressure cover to shift forward; an accommodating cavity is formed between the first valley, the first peak and the second valley, and an elastic extrusion soft ring is installed in the accommodating cavity, and the outer edges of the extrusion soft ring are respectively in contact with the secondary supporting inclined surface and the top surface of the inclined boss, and the inner edge of the extrusion soft ring is in contact with the cavity wall of the accommodating cavity.

[0008] With the above design, the extruded soft ring fills the accommodating cavity under the pressure when the pressure cover is adjusted, and can undergo elastic deformation to elastically support the first peak, thereby reducing the leakage risk of the accommodating cavity and improving the sealing effect between the first peak and the butterfly valve, so that the sealing structure can achieve more uniform compensation in the radial direction; and the reserved adjustment interval allows the pressure cover to move forward, which is convenient for fine-tuning of the preload force.

[0009] In a possible design, the first valley portion abuts against the top surface of the inclined boss.

[0010] With the above design, under the adjustment force of the gland or the pressure of the medium, the first valley will produce a slight forward displacement. Due to the top surface shape of the inclined boss, the first valley forms a centripetal force, driving the first peak to be further pressed against the butterfly plate, further improving the reliability of the seal.

[0011] In a possible design, a soft sealing ring is installed between the front side of the first valley and the inner wall of the valve body, and the soft sealing ring contacts the outer edge of the butterfly plate to form a seal.

[0012] With the above design, the soft sealing ring contacts the outer edge of the butterfly plate to form an additional soft seal, which can effectively prevent the fluid from leaking from the gap between the front end of the first valley and the butterfly plate, further improving the overall sealing performance of the sealing structure, especially for some occasions with requirements for soft and hard seals, and can better meet the needs; at the same time, the soft sealing ring has a certain elasticity and flexibility, and can play a role of buffering and shock absorption during the opening and closing process of the butterfly plate, reducing the impact force of the butterfly plate on the sealing structure, and reducing the wear and fatigue of the sealing components.

[0013] In a possible design, an annular groove is provided on the inner wall of the gland, the third valley portion abuts against the groove wall of the annular groove, and sealing gaskets installed in the annular groove are respectively provided on the front and rear sides of the third valley portion.

[0014] The above design can effectively prevent fluid from leaking from the gap between the third valley and the annular groove, thereby improving the sealing performance of the sealing structure. At the same time, the structure is more stable and reduces component loosening and displacement caused by factors such as vibration and pressure fluctuations.

[0015] In one possible design, a limiting prism is provided on the outer circle of the gland, a screw is threaded onto the valve body, the nut of the screw abuts against the limiting prism, and a pre-adjusted gap is reserved between the limiting prism and the valve body for the limiting prism to shift forward.

[0016] The above design allows the axial position of the gland to be precisely controlled and limited. By adjusting the position of the screw, the preload force of the sealing system can be flexibly adjusted to adapt to different working environments and requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the utility model;

[0018] Figure 2 This is a schematic diagram of the force applied to the gland after adjustment of the utility model;

[0019] Among them, 1. Pressure cap; 11. Main support slope; 12. Secondary support slope; 13. Ring groove; 14. Limiting prism; 2. Butterfly plate; 3. Hard seal valve seat; 31. First peak; 32. Second peak; 33. First valley; 34. Second valley; 35. Third valley; 36. Accommodation cavity; 4. Valve body; 41. Inclined boss; 5. Extrusion soft ring; 6. Soft sealing ring; 7. Sealing gasket; 8. Screw; 91. Adjustment interval; 92. Pre-adjustment interval. DETAILED DESCRIPTION

[0020] like Figures 1 to 2The elastic sealing structure of a butterfly valve shown includes a gland 1, a butterfly plate 2, a hard-sealed valve seat 3, and a valve body 4. The gland 1 can be adjusted axially forward or backward and installed in the valve body 4, wherein the forward direction is the direction axially close to the valve stem, and the backward direction is the opposite, that is, the direction axially away from the valve stem and the valve body 4. The hard-sealed valve seat 3 is made of elastic metal material and has an "M"-shaped cross-section. The hard-sealed valve seat 3 includes a first peak 31 and a second peak 32 at the inner edge position and a first valley 33, a second valley 34, and a third valley 35 at the outer edge position. The first peak 31 is located between the first valley 33 and the second valley 34, and the second peak 32 is located between the second valley 34 and the third valley 35. The first peak 31 and the second peak 32 elastically contact different positions on the outer edge of the butterfly plate 2 to form a double-pass seal. The surfaces of the first peak 31 and the second peak 32 must be finely ground and polished to a surface roughness that meets specific requirements, such as Ra1.6 to Ra3.2μm, to ensure good contact and sealing with the outer edge of the butterfly disc 2. The cross-sectional profile of the outer edge of the butterfly disc 2 is an arc or an inclined plane. The first valley 33 is supported on the inner wall of the valve body 4, while the second valley 34 and the third valley 35 are supported on different inner wall positions of the gland 1. A main support slope 11 is formed on the inner wall of the gland 1. The main support slope 11 begins from the inner wall of the gland 1 and tilts axially backward toward the center of the valve body 4. The inclination angle of the main support slope 11 can be designed according to the specific size and operating requirements of the butterfly valve, generally ranging from 3° to 18°. For example, when the nominal diameter of the butterfly valve is DN100, the inclination angle of the main support slope 11 can be set to 15°. This inclined shape allows the second valley 34 to shrink toward the center of the valve body 4 through the action of the main support bevel 11 when the gland 1 is adjusted and shifted inward. When the gland 1 moves axially forward by approximately 1 mm, the main support bevel 11 pushes the second valley 34 toward the center of the valve body 4, radially compressing the first and second peaks 31, 32 by 0.2-0.5 mm, thereby adjusting the sealing preload (the arrows in the figure indicate the direction of force applied by the gland 1 after adjustment). If the butterfly plate 2 and the hard-seal valve seat 3 become worn after a period of use, the position of the gland 1 can be appropriately adjusted during repair or maintenance to ensure that the second peak 32 fits more closely against the outer edge of the butterfly plate 2, compensating for the gap caused by wear and maintaining good sealing performance.

[0021] A secondary supporting slope 12 is formed on the inner wall of the pressure cover 1, and the secondary supporting slope 12 is inclined in the same direction as the main supporting slope 11. The inclination direction of the secondary supporting slope 12 is consistent with the inclination direction of the main supporting slope 11, and the inclination angles of the two are close, ensuring the radial force uniformity of the entire sealing structure; an inclined boss 41 is formed on the inner wall of the valve body 4, and the top surface of the inclined boss 41 is inclined axially forward from the inner wall of the valve body 4 and toward the center of the valve body 4; an adjustment gap 91 is reserved between the inclined boss 41 and the pressure cover 1 for the pressure cover 1 to shift forward; an accommodating cavity 36 is formed between the first valley 33, the first peak 31 and the second valley 34, and an elastic extrusion soft ring 5 is installed in the accommodating cavity 36. The extrusion soft ring 5 is made of rubber material or polyurethane material with good elasticity and wear resistance. The outer edges of the extrusion soft ring 5 are respectively abutted against the secondary supporting slope 12 and the top surface of the inclined boss 41, and the inner edge of the extrusion soft ring 5 abuts against the cavity wall of the accommodating cavity 36. Among them, the adjustment interval 91 is designed according to the adjustment stroke of the gland 1 and the overall layout of the sealing structure, and is generally between 2-5 mm. When the gland 1 is adjusted, the secondary support slope 12 pushes the extrusion soft ring 5 to shrink toward the center of the valve body 4, further providing radial elastic compensation force and enhancing the sealing contact pressure. The main support slope 11 acts first to achieve initial diameter reduction, and the secondary support slope 12 cooperates with the extrusion soft ring 5 to provide secondary compensation. Of course, it is necessary to adjust the gland 1 in stages to avoid plastic deformation of the valve seat caused by excessive adjustment. The extrusion soft ring 5 fills the accommodating cavity 36, which not only transmits pressure as an elastic medium, but also absorbs the impact vibration of the medium, thereby improving the sealing stability of the valve seat under dynamic conditions.

[0022] The first valley 33 abuts the top surface of the inclined boss 41, which provides a certain degree of axial restraint for the valve seat. At the same time, its inclined top surface converts part of the axial adjustment force into radial contraction force. Together with the main support inclined surface 11, this forces the first peak 31 to adhere more closely to the butterfly disc 2.

[0023] A soft sealing ring 6 is installed between the front side of the first valley 33 and the inner wall of the valve body 4. The soft sealing ring 6 contacts the outer edge of the butterfly disc 2 to form a seal. The soft sealing ring 6 is made of a rubber material with moderate hardness and good elasticity, such as fluororubber, nitrile rubber, etc., to adapt to different working environments and media requirements. The cross-sectional shape of the soft sealing ring 6 can be rectangular or trapezoidal, and the position in contact with the butterfly disc 2 is circular. The front and rear side surfaces of the soft sealing ring 6 are provided with an anti-slip texture or a coating that increases friction to prevent the soft sealing ring 6 from slipping during the rotation of the butterfly disc 2. When the butterfly disc 2 rotates in the valve body 4, the soft sealing ring 6 fits tightly against the outer edge of the butterfly disc 2 to form a soft seal. Because the soft sealing ring 6 has good elasticity and flexibility, even if there is a small gap or unevenness between the butterfly disc 2 and the hard sealing valve seat 3, the soft sealing ring 6 can fill the gap through its own elastic deformation to prevent fluid leakage.

[0024] The inner wall of the gland 1 is defined by an annular groove 13, with the third valley 35 abutting the inner wall of the annular groove 13. Sealing gaskets 7 are installed in the annular groove 13 on the front and rear sides of the third valley 35. The annular groove 13 has inclined walls, which help the third valley 35 provide compensatory support for the second peak 32. The sealing gasket 7 allows the third valley 35 to slide along the annular groove 13 during gland 1 adjustment while also preventing leakage of the medium through the gap between the gland 1 and the valve seat.

[0025] A retaining prism 14 is convexly mounted on the outer circumference of the gland 1. A screw 8 is threaded onto the valve body 4, with the nut of screw 8 abutting against the retaining prism 14. A pre-adjusted gap 92 is reserved between the retaining prism 14 and the valve body 4 to allow the retaining prism 14 to shift forward. To adjust the seal preload, the operator rotates screw 8 to move the gland 1 axially, achieving convenient and precise pre-adjustment of the seal structure. During adjustment, the appropriate sealing pressure is determined by observing the rotation of the butterfly plate 2 and fluid leakage, ensuring optimal sealing performance of the butterfly valve.

Claims

1. An elastic sealing structure of a butterfly valve, comprising a gland (1), a butterfly plate (2), a hard sealing valve seat (3) and a valve body (4), wherein the gland (1) is axially adjustable and installed in the valve body (4), and is characterized in that: The hard sealing valve seat (3) is made of elastic metal material and has an "M"-shaped cross section. The hard sealing valve seat (3) includes a first peak (31) and a second peak (32) at the inner edge position and a first valley (33), a second valley (34), and a third valley (35) at the outer edge position. The first peak (31) is located between the first valley (33) and the second valley (34), and the second peak (32) is located between the second valley (34) and the third valley (35). The first peak (31) and the second peak (32) are elastically in contact with the outer edge of the butterfly plate (2). The first valley (33) is supported on the inner wall of the valve body (4), and the second valley (34) and the third valley (35) are supported on different inner wall positions of the gland (1). A main supporting inclined surface (11) is formed on the inner wall of the gland (1). The main supporting inclined surface (11) starts from the inner wall of the gland (1) and is inclined axially backward and toward the center of the valve body (4). The second valley (34) is pressed against the main supporting inclined surface (11) so as to reduce its diameter toward the center of the valve body (4) through the main supporting inclined surface (11) when the gland (1) is adjusted and displaced forward.

2. The elastic sealing structure of a butterfly valve according to claim 1, characterized in that: A secondary support inclined surface (12) is formed on the inner wall of the pressure cover (1), and the secondary support inclined surface (12) and the main support inclined surface (11) are inclined in the same direction; an inclined boss (41) is formed on the inner wall of the valve body (4), and the top surface of the inclined boss (41) starts from the inner wall of the valve body (4) and is inclined axially forward and toward the center of the valve body (4); an adjustment gap (91) is reserved between the inclined boss (41) and the pressure cover (1) for the pressure cover (1) to shift forward; a receiving cavity (36) is formed between the first valley (33), the first peak (31) and the second valley (34), and an elastic extrusion soft ring (5) is installed in the receiving cavity (36), and the outer edges of the extrusion soft ring (5) are respectively abutted against the secondary support inclined surface (12) and the top surface of the inclined boss (41), and the inner edge of the extrusion soft ring (5) is abutted against the cavity wall of the receiving cavity (36).

3. The elastic sealing structure of a butterfly valve according to claim 2, characterized in that: The first valley portion (33) abuts against the top surface of the inclined boss (41).

4. The elastic sealing structure of a butterfly valve according to claim 3, characterized in that: A soft sealing ring (6) is installed between the front side of the first valley (33) and the inner wall of the valve body (4), and the soft sealing ring (6) contacts the outer edge of the butterfly plate (2) to form a seal.

5. The elastic sealing structure of a butterfly valve according to claim 1 or 2, characterized in that: An annular groove (13) is formed on the inner wall of the gland (1), the third valley portion (35) abuts against the inner wall of the annular groove (13), and sealing gaskets (7) installed in the annular groove (13) are respectively provided on the front and rear sides of the third valley portion (35).

6. The elastic sealing structure of a butterfly valve according to claim 1 or 2, characterized in that: The outer circle of the gland (1) is convexly provided with a limiting prism (14), the valve body (4) is screwed with a screw (8), the nut of the screw (8) abuts against the limiting prism (14), and a pre-adjusted gap (92) is reserved between the limiting prism (14) and the valve body (4) for the limiting prism (14) to shift forward.

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