Valve sealing structure and ball valve

Abstract

The valve sealing structure is used for being connected to the communicating position of an inner cavity of a valve body and a channel of a valve deck and comprises a C-shaped ball body and a PTFE sealing ring, the C-shaped ball body is used for being rotationally connected into the inner cavity of the valve body, and a first metal sealing ring is arranged on the outer surface of the C-shaped ball body; the PTFE sealing ring is used for being installed at a liquid outlet of an inner cavity of the valve body, and the PTFE sealing ring and the liquid outlet of the inner cavity are concentrically arranged. A second metal sealing ring is concentrically arranged on the end face, deviating from the C-shaped ball body in the axial direction, of the PTFE sealing ring. The end face, deviating from the PTFE sealing ring in the axial direction, of the second metal sealing ring is provided with an elastic pressing assembly. The elastic pressing assembly is used for applying pre-tightening pressure towards the PTFE sealing ring in the axial direction to the second metal sealing ring. And when the C-shaped ball body is in a closed state, the first metal sealing ring and the PTFE sealing ring are concentrically arranged. Reliable sealing performance can be always kept under different working condition temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of valve manufacturing, and in particular to a valve sealing structure and a ball valve. Background Art

[0002] Ball valve is one of the most widely used valves. It has a simple structure, reliable sealing, easy maintenance, and the sealing surface and the ball are often in a closed state, which is not easily eroded by the medium. It is widely used in petroleum, chemical industry, metallurgy, light industry, food, atomic energy, aviation and other fields.

[0003] A ball valve generally comprises a valve body and a valve cover connected by bolts. An inner cavity is provided in the valve body, and a channel is provided in the valve cover. The liquid inlet of the channel is connected to the liquid outlet of the inner cavity, thereby enabling the circulation of the medium in the ball valve. A ball is rotatably connected in the inner cavity and driven to rotate by a valve stem. When the ball valve needs to be shut off, the ball is driven by the valve stem to rotate along the axis of the valve stem to the connection point between the liquid inlet of the channel and the liquid outlet of the inner cavity, thereby closing the ball valve. In order to ensure the sealing performance of the ball valve when it is closed, a sealing structure is required to be in contact with the metal outer surface of the ball for sealing. Most existing sealing structures generally use sealing materials (such as O-rings, packings, lip-type sealing rings, etc.) in contact with the metal outer surface of the ball to form a non-metallic soft sealing pair to achieve soft sealing. However, the sealing performance of this sealing method is poor in reliability under sudden high temperature conditions (such as above 250°C), and the sealing effect is not ideal. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the sealing structure adopts a non-metallic soft sealing pair and the metal outer surface of the sphere to achieve soft sealing, and cannot maintain reliable sealing when the operating temperature exceeds the critical value due to an emergency, thereby providing a valve sealing structure and a ball valve.

[0005] According to a first aspect of the present invention, a valve sealing structure is provided, which is applied to the connection between the inner cavity of a valve body and the passage of a valve cover, and the valve sealing structure includes:

[0006] A C-shaped ball, adapted to be rotatably connected to the inner cavity of the valve body, wherein the C-shaped ball has a closed state in which the passage between the inner cavity of the valve body and the valve cover is blocked, and an open state in which the passage between the inner cavity of the valve body and the valve cover is connected;

[0007] a first metal sealing ring, disposed on the outer surface of the C-shaped sphere;

[0008] The PTFE sealing ring is used to be installed at the liquid outlet of the inner cavity of the valve body and is arranged concentrically with the liquid outlet of the inner cavity;

[0009] a second metal sealing ring, arranged on the end surface of the PTFE sealing ring axially away from the C-shaped sphere;

[0010] The elastic pressing component is arranged on the end face of the second metal sealing ring axially away from the PTFE sealing ring, and is used to apply a pre-tightening pressure axially towards the PTFE sealing ring to the second metal sealing ring;

[0011] When the C-shaped sphere is in the closed state, the first metal sealing ring and the PTFE sealing ring are concentrically arranged.

[0012] A valve sealing structure according to the present invention has at least the following technical effects:

[0013] By concentrically arranging a second metal sealing ring at one end of the PTFE sealing ring axially away from the C-shaped sphere, and applying a pre-tightening pressure axially towards the PTFE sealing ring to the second metal sealing ring through the elastic pressing component. On the one hand, when the working condition temperature of the ball valve equipped with this valve sealing structure does not exceed the melting critical temperature of PTFE, the pre-tightening pressure applied by the elastic pressing component on the second metal sealing ring is transmitted to the PTFE sealing ring, making the PTFE sealing ring closely fit with the first metal sealing ring to achieve reliable sealing. On the other hand, when the working environment of the ball valve equipped with this valve sealing structure is abnormal (such as a fire), causing the working condition temperature to exceed the melting critical temperature of PTFE, the PTFE sealing ring gradually melts and disappears. At this time, the second metal sealing ring moves axially towards the direction close to the C-shaped sphere under the action of the pre-tightening pressure applied by the elastic pressing component and enters the position where the original PTFE sealing ring was located, realizing the close fit of the second metal sealing ring and the first metal sealing ring to ensure reliable sealing under abnormal high-temperature working conditions. This valve sealing structure forms two layers of sealing through the PTFE sealing ring and the second metal sealing ring, ensuring that the ball valve equipped with this valve sealing structure can simultaneously combine the advantages of using a non-metallic soft sealing pair for sealing and using a metal hard sealing pair for sealing, so as to ensure that the ball valve equipped with this valve sealing structure always maintains reliable sealing performance under different working condition temperatures.

[0014] Preferably, the elastic pressing component includes a plurality of connecting columns. The plurality of connecting columns are used to be connected to the end face of the valve body axially towards the valve cover and are arranged at intervals along the circumferential direction of the PTFE sealing ring; a sealing pressing ring is slidably arranged axially on the connecting column. The second metal sealing ring is connected to the end face of the sealing pressing ring facing the PTFE sealing ring. A limiting portion is arranged at one end of the connecting column axially away from the C-shaped sphere. An elastic member is sleeved on the connecting column, and both ends of the elastic member are respectively connected to the limiting portion and the axially facing end faces of the sealing pressing ring. The elastic member has an initial state of being compressed and storing energy.

[0015] Preferably, the elastic pressing assembly further includes a plurality of connecting bolts and threaded holes corresponding to the connecting bolts one by one. The threaded holes are used to be arranged on the end face of the valve body facing the valve cover along the axial direction, and the connecting bolts are threadedly connected in the threaded holes; the screw part of the connecting bolt forms the connecting column, and the bolt head of the connecting bolt forms the limiting part;

[0016] And / or, the elastic member is arranged as a helical spring or a disc spring.

[0017] Preferably, the cross-sectional shape of the second metal sealing ring is arranged as a wedge shape, and a circumferential wedge-shaped groove is recessed on the end face of the PTFE sealing ring facing the second metal sealing ring.

[0018] Preferably, the outer peripheral surface of the first metal sealing ring is arranged as a first spherical surface, and the inner peripheral surface of the PTFE sealing ring is arranged as a second spherical surface, and the second spherical surface matches the first spherical surface;

[0019] And / or, the outer peripheral surface of the first metal sealing ring is arranged as a first spherical surface, and the inner peripheral surface of the second metal sealing ring is arranged as a third spherical surface, and the third spherical surface matches the first spherical surface;

[0020] And / or, a positioning groove is recessed on the outer surface of the C-shaped sphere, the first metal sealing ring is embedded in the positioning groove, and the first metal sealing ring is detachably connected to the C-shaped sphere through fastening screws.

[0021] A ball valve according to the second aspect of the present invention includes a valve body, a valve cover and a valve sealing structure. An inner cavity is provided in the valve body, a channel is provided in the valve cover, the valve cover is connected to the liquid outlet end of the valve body through bolts, and the inner cavity is communicated with the channel; the valve sealing structure adopts the valve sealing structure provided in the first aspect above.

[0022] A ball valve according to the present invention has at least the following technical effects:

[0023] A second metal sealing ring is concentrically arranged at one end of the PTFE sealing ring in the valve sealing structure axially away from the C-shaped sphere, and a pre-tightening pressure is applied to the second metal sealing ring axially towards the PTFE sealing ring through an elastic pressing assembly. On the one hand, when the operating temperature of this ball valve does not exceed the melting critical temperature of PTFE, the pre-tightening pressure applied by the elastic pressing assembly on the second metal sealing ring is transmitted to the PTFE sealing ring, making the PTFE sealing ring closely fit with the first metal sealing ring to achieve reliable sealing. On the other hand, when the working environment of this ball valve is abnormal (such as a fire occurring), causing the operating temperature to exceed the melting critical temperature of PTFE, the PTFE sealing ring gradually melts and disappears. At this time, the second metal sealing ring moves axially towards the direction close to the C-shaped sphere under the action of the pre-tightening pressure applied by the elastic pressing assembly and enters the position where the original PTFE sealing ring was located, achieving reliable sealing under abnormal high-temperature conditions by using the close fit between the second metal sealing ring and the first metal sealing ring. The valve sealing structure forms two layers of sealing through the PTFE sealing ring and the second metal sealing ring, ensuring that this ball valve can simultaneously incorporate the advantages of sealing with non-metallic soft sealing pairs and the advantages of sealing with metal hard sealing pairs, thereby ensuring that this ball valve always maintains reliable sealing performance under different operating temperatures.

[0024] Preferably, an installation hole is formed through the valve body along the rotation axis direction of the C-shaped sphere, and the installation hole communicates with the inner cavity. The C-shaped sphere is connected to a valve stem through a first limit screw, the valve stem is rotatably connected in the installation hole, and one end of the valve stem passes through the installation hole and extends to the outside of the valve body; a sealing packing is filled between the side surface of the valve stem and the inner wall of the installation hole.

[0025] Preferably, the installation hole is a stepped hole, the large-diameter part of the installation hole is located at one end of the small-diameter part of the installation hole away from the inner cavity, and the sealing packing is filled between the inner wall of the large-diameter part of the installation hole and the side surface of the valve stem; one end of the sealing packing away from the small-diameter part of the installation hole abuts against a packing gland, and the packing gland is fixedly connected to the valve body.

[0026] Preferably, a bearing ring is arranged between the inner wall of the small-diameter part of the installation hole and the side surface of the valve stem.

[0027] Preferably, one end of the C-shaped sphere away from the valve stem is connected to a support rod through a second limit screw, the support rod is concentric with the valve stem, and the support rod is rotatably connected to the surrounding wall of the inner cavity.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Brief Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of a ball valve equipped with a valve seal structure of this embodiment;

[0031] Figure 2 It is Figure 1 an enlarged schematic view of part A in

[0032] Figure 3 It is Figure 2 a schematic structural diagram after the PTFE seal ring in melts and disappears and the second metal seal ring moves into the position of the original PTFE seal ring;

[0033] Figure 4 It is a schematic structural diagram of a valve seal structure of this embodiment with the elastic member set as a disc spring.

[0034] Explanation of reference numerals:

[0035] 1 - valve body, 11 - inner cavity;

[0036] 2 - valve cover, 21 - passage;

[0037] 3 - C-shaped sphere, 31 - first metal seal ring, 311 - first spherical surface, 32 - fastening screw, 33 - first limit screw, 34 - second limit screw, 35 - support rod;

[0038] 41 - PTFE seal ring, 411 - wedge-shaped groove, 42 - second metal seal ring, 421 - third spherical surface;

[0039] 51 - seal pressing ring, 511 - sliding hole, 52 - connecting bolt, 53 - helical spring, 54 - disc spring;

[0040] 6 - valve stem;

[0041] 71 - packing, 72 - packing gland, 73 - bearing ring, 74 - fastening bolt. Specific embodiments

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Embodiment 1

[0047] As Figures 1 to 3Shown is a valve sealing structure and a ball valve provided by this embodiment, which are applied and connected to the communication part between the inner cavity 11 of the valve body 1 and the passage 21 of the valve cover 2. The valve sealing structure includes a C-shaped sphere 3 and a PTFE sealing ring 41. The C-shaped sphere 3 is used for rotatably connecting in the inner cavity 11 of the valve body 1. The C-shaped sphere 3 has a closed state in which the inner cavity 11 of the valve body 1 and the passage 21 of the valve cover 2 are blocked, and an open state in which the inner cavity 11 of the valve body 1 and the passage 21 of the valve cover 2 are conducted. A first metal sealing ring 31 is arranged on the outer surface of the C-shaped sphere 3. The PTFE sealing ring 41 is used for being installed at the liquid outlet of the inner cavity 11 of the valve body 1 and is concentrically arranged with the liquid outlet of the inner cavity 11. A second metal sealing ring 42 is concentrically arranged on the end face of the PTFE sealing ring 41 axially away from the C-shaped sphere 3. An elastic pressing assembly is arranged on the end face of the second metal sealing ring 42 axially away from the PTFE sealing ring 41. The elastic pressing assembly is used for applying a pre-tightening pressure axially towards the PTFE sealing ring 41 to the second metal sealing ring 42. When the C-shaped sphere 3 is in the closed state, the first metal sealing ring 31 and the PTFE sealing ring 41 are concentrically arranged. When the PTFE sealing ring 41 is not melted, the first metal sealing ring 31 and the PTFE sealing ring 41 are in contact and sealed with each other. After the PTFE sealing ring 41 melts and disappears, the first metal sealing ring 31 and the second metal sealing ring 42 are in contact and sealed. It can be understood that the axial direction mentioned in this embodiment refers to Figure 1 the axial direction in

[0048] In the valve sealing structure of this embodiment, a second metal sealing ring 42 is concentrically arranged at one end of the PTFE sealing ring 41 axially away from the C-shaped sphere 3, and an elastic pressing assembly applies a pre-tightening pressure axially towards the PTFE sealing ring 41 to the second metal sealing ring 42. On the one hand, when the working condition temperature of the ball valve equipped with the valve sealing structure of this embodiment does not exceed the melting critical temperature of PTFE (such as Figure 2 shown), the pre-tightening pressure applied by the elastic pressing assembly on the second metal sealing ring 42 is transmitted to the PTFE sealing ring 41, so that the PTFE sealing ring 41 is closely attached to the first metal sealing ring 31 to achieve reliable sealing. On the other hand, when the working environment of the ball valve equipped with the valve sealing structure of this embodiment is abnormal (for example, a fire occurs), the working condition temperature (specifically, such as 250 °C) exceeds the melting critical temperature of PTFE, and the PTFE sealing ring 41 gradually melts until it disappears. At this time, the second metal sealing ring 42 moves axially towards the direction close to the C-shaped sphere 3 under the action of the pre-tightening pressure applied by the elastic pressing assembly and enters the position where the original PTFE sealing ring 41 was located (such as Figure 3As shown, the second metal sealing ring 42 is tightly fitted to the first metal sealing ring 31, ensuring reliable sealing under abnormally high temperature conditions. The valve sealing structure of this embodiment forms a two-layer seal using the PTFE sealing ring 41 and the second metal sealing ring 42, ensuring that the ball valve equipped with the valve sealing structure of this embodiment can simultaneously combine the advantages of sealing using a non-metallic soft sealing pair with the advantages of sealing using a metal hard sealing pair, thereby ensuring that the ball valve equipped with the valve sealing structure of this embodiment always maintains reliable sealing performance under different operating temperatures; in particular, it plays a fire prevention role, ensuring that the ball valve equipped with the valve sealing structure of this embodiment can maintain reliable sealing performance when in a closed state even in the event of a fire.

[0049] like Figures 1 to 3 As shown, in some embodiments of the present invention, the elastic clamping assembly includes a plurality of connecting columns, preferably four connecting columns here, the four connecting columns are used to connect to the end face of the valve body 1 axially facing the valve cover 2, and are arranged at intervals along the circumference of the PTFE sealing ring 41; a sealing pressure ring 51 is axially slidingly provided on the connecting column, the second metal sealing ring 42 is connected to the end face of the sealing pressure ring 51 facing the PTFE sealing ring 41, a limiting portion is provided at one end of the connecting column axially away from the C-shaped sphere 3, an elastic member is sleeved on the connecting column, and both ends of the elastic member are respectively connected to the limiting portion and the two end faces of the sealing pressure ring 51 axially facing each other, and the elastic member has an initial state of being compressed and storing force. Because the elastic member is initially compressed and force-accumulating in its initial state after assembly, the elastic member always applies a pre-tightening pressure to the sealing pressure ring 51 to drive the sealing pressure ring 51 to maintain a tendency to move axially toward the C-shaped sphere 3, so that after the PTFE sealing ring 41 gradually melts and disappears, and under the sliding cooperation of the connecting column and the sealing pressure ring 51, the pre-tightening pressure applied by the elastic member can drive the second metal sealing ring 42 to move axially in a straight line along with the sealing pressure ring 51 until the second metal sealing ring 42 enters the position where the PTFE sealing ring 41 was originally located, thereby ensuring that the operating temperature of the ball valve equipped with the valve sealing structure of this embodiment can still maintain reliable sealing performance after the PTFE sealing ring 41 gradually melts and disappears due to sudden situations such as fire.

[0050] like Figure 2 and Figure 3As shown, specifically, the sealing compression ring 51 is provided with sliding holes 511 corresponding to the connecting columns one by one. The sliding holes 511 penetrate through the sealing compression ring 51 along the axial direction, and the connecting columns are slidably connected in the sliding holes 511 along the axial direction. Through the sliding connection relationship between the sliding holes 511 and the connecting columns, it is ensured that after the PTFE sealing ring 41 gradually melts and disappears, the second metal sealing ring 42 moves linearly along the axial direction under the driving of the pre-tightening pressure applied by the elastic member, so as to ensure that the second metal sealing ring 42 is accurately pushed into the position where the original PTFE sealing ring 41 is located.

[0051] In specific applications, the number of the connecting columns can be reasonably increased or decreased according to the cross-sectional size of the liquid outlet of the inner cavity 11 perpendicular to the axial direction. For example, in other embodiments, the connecting columns are provided with two, three, five or other numbers.

[0052] As Figures 1 to 3 shown, in some embodiments of the present invention, the elastic pressing assembly further includes a plurality of connecting bolts 52 and threaded holes corresponding to the connecting bolts 52 one by one. The threaded holes are used to be arranged on the end face of the valve body 1 facing the valve cover 2 along the axial direction, and the connecting bolts 52 are threadedly connected in the threaded holes; the screw part of the connecting bolt 52 forms the connecting column, and the screw head of the connecting bolt 52 forms the limiting part. By integrally forming the connecting column and the limiting part to form the connecting bolt 52, and a threaded hole is provided at the position corresponding to the connecting bolt 52 on the end face of the valve body 1 facing the valve cover 2 along the axial direction. On the one hand, the depth of the connecting bolt 52 threaded in the threaded hole can be controlled, that is, the distance between the screw head of the connecting bolt 52 and the sealing compression ring 51 along the axial direction can be adjusted, so as to flexibly adjust the pre-compression amount of the elastic member in the initial state, and further conveniently realize the fine adjustment of the sealing specific pressure between the PTFE sealing ring 41 and the first metal sealing ring 31.

[0053] As Figure 2 and Figure 3 shown, specifically, the elastic member is set as a helical spring 53. The helical spring 53 provides a pre-tightening pressure to drive the second metal sealing ring 42 to maintain a movement trend along the axial direction towards the PTFE sealing ring 41, which can not only ensure the close fit between the PTFE sealing ring 41 and the first metal sealing ring 31 to achieve reliable sealing, but also ensure that after the PTFE sealing ring 41 melts and disappears, the second metal sealing ring 42 is driven to move into the position where the original PTFE sealing ring 41 is located, so as to achieve the close fit between the second metal sealing ring 42 and the first metal sealing ring 31 to achieve reliable sealing. As an alternative to the above technical solution, as Figure 4 shown, the elastic member is set as a disc spring 54.

[0054] As Figure 2As shown, in some embodiments of the present invention, the cross-sectional shape of the second metal sealing ring 42 is set to a wedge shape, and a circumferential wedge-shaped groove 411 is recessed on the end surface of the PTFE sealing ring 41 facing the second metal sealing ring 42. By fitting the end surface of the second metal sealing ring 42 facing the PTFE sealing ring 41 into the wedge-shaped groove 411, after the second metal sealing ring 42 is subjected to the pre-tightening pressure applied by the elastic member, the PTFE sealing ring 41 is more closely attached to the first metal sealing ring 31, achieving a more reliable seal.

[0055] As Figure 2 shown, in some embodiments of the present invention, the outer peripheral surface of the first metal sealing ring 31 is set to a first spherical surface 311, and the inner peripheral surface of the PTFE sealing ring 41 is set to a second spherical surface, and the second spherical surface matches the first spherical surface 311. Through the cooperation of the first spherical surface 311 and the second spherical surface, the contact between the first metal sealing ring 31 and the PTFE sealing ring 41 is a spherical contact. On the one hand, it can make the pre-tightening pressure generated by the elastic member act evenly on the PTFE sealing ring 41 and the first metal sealing ring 31, preventing the service life of the valve sealing structure in this embodiment from being reduced due to uneven friction; on the other hand, it can increase the contact area and make the seal more reliable.

[0056] As Figure 2 and Figure 3 shown, in some embodiments of the present invention, the inner peripheral surface of the second metal sealing ring 42 is set to a third spherical surface 421, and the third spherical surface 421 matches the first spherical surface 311. After the PTFE sealing ring 41 melts and disappears and the second metal sealing ring 42 moves into the position where the original PTFE sealing ring 41 was located, the cooperation of the third spherical surface 421 and the first spherical surface 311 makes the contact between the second metal sealing ring 42 and the first metal sealing ring 31 a spherical contact. On the one hand, it can make the pre-tightening pressure generated by the elastic member act evenly on the second metal sealing ring 42 and the first metal sealing ring 31, preventing the service life of the valve sealing structure in this embodiment from being reduced due to uneven friction; on the other hand, it can increase the contact area and make the seal more reliable.

[0057] As Figure 1As shown, in some embodiments of the present invention, a positioning groove is recessed on the outer surface of the C-shaped sphere 3, and the first metal sealing ring 31 is embedded in the positioning groove. The first metal sealing ring 31 is detachably connected to the C-shaped sphere 3 via a fastening screw 32. The positioning function of the positioning groove facilitates more precise assembly of the first metal sealing ring 31 on the C-shaped sphere 3, further improving the sealing reliability of the valve sealing structure of this embodiment. At the same time, the first metal sealing ring 31 is connected to the C-shaped sphere 3 by the fastening screw 32. On the one hand, it is convenient to install and connect the first metal sealing ring 31 to the C-shaped sphere 3 to form an integral body. On the other hand, it is also convenient to remove the first metal sealing ring 31 from the C-shaped sphere 3 for maintenance and replacement.

[0058] Specifically, the sealing connection surface of the first metal sealing ring 31 is sprayed with a chromium carbide coating, which increases the hardness of the sealing connection surface of the first metal sealing ring 31 and the wear resistance of the first metal sealing ring 31; and ensures reliable sealing with the second metal sealing ring 42 under an operating temperature environment exceeding the critical melting temperature of PTFE.

[0059] Embodiment 2

[0060] like Figures 1 to 4 The figure shows a ball valve provided in this embodiment, including a valve body 1, a valve cover 2 and a valve sealing structure. The valve body 1 is provided with an inner cavity 11, the valve cover 2 is provided with a channel 21, the valve cover 2 is connected to the liquid outlet end of the valve body 1 by bolts, and the inner cavity 11 is connected to the channel 21; the valve sealing structure adopts the valve sealing structure described in Example 1.

[0061] The ball valve of this embodiment is provided with a second metal sealing ring 42 concentrically at one end of the PTFE sealing ring 41 in the valve sealing structure, which is axially away from the C-shaped ball 3, and a pre-tightening pressure is applied to the second metal sealing ring 42 in the axial direction toward the PTFE sealing ring 41 by the elastic pressing component. On the one hand, when the operating temperature of the ball valve of this embodiment does not exceed the critical melting temperature of PTFE (such as Figure 2 As shown in the figure), the pre-tightening pressure applied by the elastic pressing assembly to the second metal sealing ring 42 is transmitted to the PTFE sealing ring 41, so that the PTFE sealing ring 41 is tightly fitted with the first metal sealing ring 31 to achieve reliable sealing; on the other hand, when the working environment of the ball valve of this embodiment is abnormal (for example, a fire occurs), the working temperature (specifically, 250°C) exceeds the melting critical temperature of PTFE, and the PTFE sealing ring 41 gradually melts and disappears. At this time, the second metal sealing ring 42 moves axially toward the direction close to the C-shaped sphere 3 under the action of the pre-tightening pressure applied by the elastic pressing assembly into the position where the original PTFE sealing ring 41 is located (as shown in the figure). Figure 3As shown, the second metal sealing ring 42 is closely attached to the first metal sealing ring 31 to ensure reliable sealing under abnormal high-temperature conditions. The valve sealing structure forms a two-layer seal through the PTFE sealing ring 41 and the second metal sealing ring 42, ensuring that the ball valve in this embodiment can simultaneously incorporate the advantages of sealing with non-metallic soft sealing pairs and metal hard sealing pairs. Thus, it ensures that the ball valve in this embodiment always maintains reliable sealing performance at different working temperatures, especially playing a role in fire prevention and ensuring reliable sealing performance when the ball valve in this embodiment is in the closed state during a fire.

[0062] As Figure 1 shown, specifically, the channel 21 is set as a stepped hole, and the large-diameter portion of the channel 21 is located at one end of the small-diameter portion of the channel 21 along the axial direction toward the inner cavity 11, so as to avoid the connecting column and the sealing pressure ring 51 when assembling the valve cover 2 and the valve body 1, thereby avoiding interference.

[0063] As Figure 1 shown, in some embodiments of the present invention, an installation hole is formed through the valve body 1 along the rotation axis direction of the C-shaped ball 3, and the installation hole is communicated with the inner cavity 11. The C-shaped ball 3 is connected to a valve stem 6 through a first limit screw 33. The valve stem 6 is rotatably connected in the installation hole, and one end of the valve stem 6 extends outside the valve body 1 through the installation hole; a sealing packing 71 is filled between the side surface of the valve stem 6 and the inner wall of the installation hole. By driving the C-shaped ball 3 to rotate in the inner cavity 11 through the valve stem 6 extending outside the valve body 1, the C-shaped ball 3 can be adjusted to switch between the closed state and the open state; by filling the sealing packing 71 between the side surface of the valve stem 6 and the inner wall of the installation hole, the sealing performance between the radial side surface of the valve stem 6 and the inner wall of the installation hole is ensured, preventing particles in the medium flowing through the inner cavity 11 and the channel 21 from entering the upper part of the valve stem 6, thereby protecting the wear of the valve stem 6 and extending the service life of the ball valve in this embodiment; also, the valve stem 6 and the C-shaped ball 3 are connected into one body through the first limit screw 33. Compared with connecting the valve stem 6 into one body by inserting it into the insertion groove of the C-shaped ball 3 through interference fit, the valve stem 6 of the ball valve in this embodiment has the function of preventing extrusion, preventing the valve stem 6 from being separated from the C-shaped ball 3 and being pushed out of the inner cavity 11 when the inner cavity 11 is under pressure. It can be understood that the rotation axis direction of the C-shaped ball 3 described in this embodiment refers to Figure 1 the first direction in

[0064] Specifically, the sealing packing 71 includes a PTFE packing member and a graphite packing member. The graphite packing member is disposed at one end of the PTFE packing member away from the inner cavity 11, forming two sealing lines, further improving the sealing performance between the radial side surface of the valve stem 6 and the inner wall of the mounting hole. Of course, here is only the preference for the material of the sealing packing 71. In practical applications, the sealing packing 71 can be other types of packings in the prior art.

[0065] As Figure 1 shown, in some embodiments of the present invention, the mounting hole is provided as a stepped hole. The large-diameter portion of the mounting hole is located at one end of the small-diameter portion of the mounting hole away from the inner cavity 11. The sealing packing 71 is filled between the inner wall of the large-diameter portion of the mounting hole and the side surface of the valve stem 6. One end of the sealing packing 71 away from the small-diameter portion of the mounting hole abuts against a packing gland 72, and the packing gland 72 is fixedly connected to the valve body 1. By the packing gland 72, the freedom of movement of the sealing packing 71 away from the inner cavity 11 is restricted, so as to ensure that the sealing packing 71 is tightly filled in the large-diameter portion of the mounting hole, thereby ensuring the plugging effect on the clearance space between the radial side surface of the valve stem 6 and the inner wall of the large-diameter portion of the mounting hole. Specifically, the packing gland 72 is connected to the valve body 1 through a fastening bolt 74.

[0066] Specifically, a bearing ring 73 is provided between the inner wall of the small-diameter portion of the mounting hole and the side surface of the valve stem 6. The bearing ring 73 can reduce the friction between the radial side surface of the valve stem 6 and the inner wall of the small-diameter portion of the mounting hole, which is convenient for rotating the valve stem 6 and can also extend the service life of the valve stem 6.

[0067] As Figure 1 shown, in some embodiments of the present invention, one end of the C-shaped sphere 3 away from the valve stem 6 is connected with a support rod 35 through a second limit screw 34. The support rod 35 is concentric with the valve stem 6, and the support rod 35 is rotatably connected to the surrounding wall of the inner cavity 11. By the support rod 35, the rotational connection area between the C-shaped sphere 3 and the surrounding wall of the inner cavity 11 is increased, so that the C-shaped sphere 3 rotates smoothly and steadily under the drive of the valve stem 6, so as to adjust the C-shaped sphere 3 to accurately switch between the closed state and the open state. At the same time, it is convenient to install and disassemble the support rod 35 and the C-shaped sphere 3 through the second limit screw 34.

[0068] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A valve sealing structure is applied to the connection at the communication between the inner cavity (11) of the valve body (1) and the passage (21) of the valve cover (2), and is characterized in that, The valve sealing structure includes: A C-shaped sphere (3) rotatably connected within the inner cavity (11) of the valve body (1). The C-shaped sphere (3) has a closed state that blocks the inner cavity (11) of the valve body (1) and the passage (21) of the valve cover (2), and an open state that conducts the inner cavity (11) of the valve body (1) and the passage (21) of the valve cover (2); A first metal sealing ring (31) provided on the outer surface of the C-shaped sphere (3); A PTFE sealing ring (41) installed at the liquid outlet of the inner cavity (11) of the valve body (1) and concentrically arranged with the liquid outlet of the inner cavity (11); A second metal sealing ring (42) concentrically arranged on the end face of the PTFE sealing ring (41) axially away from the C-shaped sphere (3); An elastic pressing assembly provided on the end face of the second metal sealing ring (42) axially away from the PTFE sealing ring (41) and used to apply a pre-tightening pressure axially towards the PTFE sealing ring (41) to the second metal sealing ring (42); When the C-shaped sphere (3) is in the closed state, the first metal sealing ring (31) and the PTFE sealing ring (41) are concentrically arranged.

2. A valve sealing structure according to claim 1, characterized in that, The elastic pressing assembly includes a plurality of connecting columns. The plurality of connecting columns are used to connect to the end face of the valve body (1) axially towards the valve cover (2) and are arranged at intervals along the circumferential direction of the PTFE sealing ring (41); A sealing pressing ring (51) is slidably arranged on the connecting column axially. The second metal sealing ring (42) is connected to the end face of the sealing pressing ring (51) towards the PTFE sealing ring (41). A limiting portion is provided at one end of the connecting column axially away from the C-shaped sphere (3). An elastic member is sleeved on the connecting column. Two ends of the elastic member are respectively connected to the limiting portion and the two end faces of the sealing pressing ring (51) axially facing each other. The elastic member has an initial state of being compressed and storing energy.

3. A valve sealing structure according to claim 2, characterized in that, The elastic pressing assembly further includes a plurality of connecting bolts (52) and threaded holes corresponding to the connecting bolts (52) one by one. The threaded holes are used to be provided on the end face of the valve body (1) axially towards the valve cover (2). The connecting bolts (52) are threadedly connected in the threaded holes; The screw portion of the connecting bolt (52) forms the connecting column, and the screw head of the connecting bolt (52) forms the limiting portion; And / or, the elastic member is set as a helical spring (53) or a disc spring (54).

4. A valve sealing structure according to claim 1, characterized in that, The cross-sectional shape of the second metal sealing ring (42) is set as a wedge shape. A circumferential wedge-shaped groove (411) is recessed on the end face of the PTFE sealing ring (41) towards the second metal sealing ring (42).

5. A valve sealing structure according to claim 1, characterized in that, The outer peripheral surface of the first metal sealing ring (31) is set as a first spherical surface (311), and the inner peripheral surface of the PTFE sealing ring (41) is set as a second spherical surface. The second spherical surface matches the first spherical surface (311); And / or, the outer peripheral surface of the first metal sealing ring (31) is provided as a first spherical surface (311), the inner peripheral surface of the second metal sealing ring (42) is provided as a third spherical surface (421), and the third spherical surface (421) matches the first spherical surface (311); And / or, a positioning groove is concavely provided on the outer surface of the C-shaped sphere (3), the first metal sealing ring (31) is fitted in the positioning groove, and the first metal sealing ring (31) is detachably connected to the C-shaped sphere (3) by fastening screws (32).

6. A ball valve, characterized in that, It includes a valve body (1), a valve cover (2) and a valve sealing structure. An inner cavity (11) is provided in the valve body (1), a channel (21) is provided in the valve cover (2), the valve cover (2) is bolted to the liquid outlet end of the valve body (1), and the inner cavity (11) communicates with the channel (21); the valve sealing structure adopts the valve sealing structure according to any one of claims 1 to 5.

7. A ball valve according to claim 6, characterized in that, An installation hole is formed through the valve body (1) along the rotation axis direction of the C-shaped sphere (3), the installation hole communicates with the inner cavity (11), the C-shaped sphere (3) is connected to a valve rod (6) by a first limit screw (33), the valve rod (6) is rotatably connected in the installation hole, and one end of the valve rod (6) extends outside the valve body (1) through the installation hole; a sealing packing (71) is filled between the side surface of the valve rod (6) and the inner wall of the installation hole.

8. A ball valve according to claim 7, wherein, The installation hole is provided as a stepped hole, the large-diameter part of the installation hole is located at one end of the small-diameter part of the installation hole away from the inner cavity (11), and the sealing packing (71) is filled between the inner wall of the large-diameter part of the installation hole and the side surface of the valve rod (6); one end of the sealing packing (71) away from the small-diameter part of the installation hole abuts against a packing gland (72), and the packing gland (72) is fixedly connected to the valve body (1).

9. A ball valve according to claim 8, characterized in that, A bearing ring (73) is provided between the inner wall of the small-diameter part of the installation hole and the side surface of the valve rod (6).

10. A ball valve according to claim 7, characterized in that, One end of the C-shaped sphere (3) away from the valve rod (6) is connected to a support rod (35) by a second limit screw (34), the support rod (35) is concentric with the valve rod (6), and the support rod (35) is rotatably connected to the surrounding wall of the inner cavity (11).

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