Highly cleanable high pressure soft seal ball valve

Abstract

The utility model discloses a kind of high-purity high-pressure-resistant soft sealing ball valves, including valve body assembly, ball core and soft sealing structure, valve body assembly is equipped with valve core cavity and is equipped with the medium channel in the both sides of valve core cavity, medium channel is communicated with valve core cavity, ball core is rotatably arranged in valve core cavity, soft sealing structure is arranged between medium channel and valve core cavity and includes valve seat, compression ring and elastic member, valve seat is annular and has hard shell and soft sealing body, hard shell is equipped with annular groove, the side of annular groove towards ball core is open structure, soft sealing body is arranged in annular groove and part from the open structure of annular groove Stretches out, elastic member is acted on valve seat by compression ring, so that the part of soft sealing body from the open structure of annular groove abuts on ball core.The utility model by hard shell part cladding soft sealing body, can improve the high-pressure resistance of valve seat, reduce its possibility of deformation due to high-pressure medium, ensure sealing performance, improve adaptability.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and in particular to a high-cleanliness, high-pressure resistant soft-seal ball valve. Background Technology

[0002] With the continuous development of fine chemicals and the constant innovation of special production processes, higher requirements have been placed on the specialness and precision of raw materials. This necessitates that ball valves also possess corresponding special characteristics, such as ensuring the high cleanliness of the process system and requiring the prohibition of oil and water. The high cleanliness requirement means that grease cannot be used for sealing and lubrication at the ball valve's sealing structure. Therefore, some high-cleanliness ball valves employ a soft-seal structure. The soft-seal structure primarily uses a valve seat made of elastic non-metallic materials (such as rubber, PTFE, and nylon) for sealing. Its flexibility can fill the microscopic unevenness of the sealing surface, forming a tight fit. For existing high-cleanliness, high-pressure resistant soft-seal ball valves, their sealing structure is relatively simple. Due to the insufficient strength of the soft valve seat material, it is prone to deformation under high-pressure media conditions, leading to seal failure. Therefore, existing high-cleanliness, high-pressure resistant soft-seal ball valves are generally only applicable to low-pressure media conditions and cannot meet the requirements of high-pressure applications. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a high-cleanliness, high-pressure resistant soft-seal ball valve. By setting a hard shell portion to cover the soft seal, it can improve the high-pressure resistance of the valve seat, reduce the possibility of valve seat deformation due to high-pressure media, ensure sealing performance, and enable the ball valve to be used in high-pressure media applications, thus improving its adaptability.

[0004] According to an embodiment of the present invention, a high-cleanliness, high-pressure resistant soft-seal ball valve includes a valve body assembly, a ball core, and a soft-seal structure. The valve body assembly has a valve core cavity and media channels on both sides of the valve core cavity. The media channels communicate with the valve core cavity. The ball core is rotatably disposed in the valve core cavity. The soft-seal structure is disposed between the media channels and the valve core cavity and includes a valve seat, a pressure ring, and an elastic element. The valve seat is annular and has a rigid shell and a soft-seal body. The rigid shell has an annular groove, and the side of the annular groove facing the ball core is open. The soft-seal body is disposed in the annular groove and partially extends out from the opening of the annular groove. The elastic element acts on the valve seat through the pressure ring, so that the portion of the soft-seal body extending out from the opening of the annular groove abuts against the ball core.

[0005] The high-cleanliness, high-pressure resistant soft-seal ball valve according to the embodiments of this utility model has at least the following beneficial effects: During use, the medium is input through the medium channel on one side of the valve body assembly. By rotating the ball core, the opening and closing control of the ball valve is achieved, thereby controlling the medium output of the medium channel on the other side. The soft-seal structure is located between the medium channel and the valve core cavity. The elastic element acts on the valve seat through a pressure ring, causing the soft-seal body of the valve seat to abut against the ball core, achieving a seal. By setting the soft-seal body in the annular groove of the rigid shell, with the portion abutting against the ball core extending from the opening of the annular groove, the rigid shell can partially cover the soft-seal body, protecting it and reducing the impact of medium pressure. This improves the high-pressure resistance of the valve seat, reduces the possibility of deformation of the valve seat due to high-pressure medium, ensures sealing performance, and enables the ball valve to be used in high-pressure medium applications, improving its adaptability.

[0006] According to some embodiments of the present invention, the soft sealing structure further includes a graphite sealing ring. The pressure ring has a first extension portion extending toward the valve seat on the side facing the valve seat. The first extension portion is annular. An annular space is defined between the inner wall of the medium channel, the first extension portion and the valve seat. The graphite sealing ring is sleeved on the valve seat and located in the annular space. The first extension portion can squeeze the graphite sealing ring under the action of the elastic member, so that the graphite sealing ring seals the gap between the valve seat and the inner wall of the medium channel.

[0007] According to some embodiments of the present invention, the soft sealing structure further includes a hard gasket ring. Two graphite sealing rings are provided, namely a first sealing ring and a second sealing ring. The hard gasket ring is sleeved on the valve seat and sandwiched between the first sealing ring and the second sealing ring. The second sealing ring is sandwiched between the first extension and the hard gasket ring.

[0008] According to some embodiments of the present invention, the first extension portion is provided with annular protrusions on the side facing the second sealing ring and the rigid gasket ring is provided with annular grooves on the side facing the rigid gasket ring and the second sealing ring is provided with annular grooves on the side facing the first extension portion. The outer contour of the single-sided cross section of the annular protrusion is shaped like a side "V", and the inner contour of the single-sided cross section of the annular groove is shaped like a side "V". The annular protrusion can be inserted into the annular groove.

[0009] According to some embodiments of the present invention, the included angle corresponding to the V-shaped outer contour of the single-sided cross section of the annular protrusion is a preset angle a, and the included angle corresponding to the V-shaped inner contour of the single-sided cross section of the annular groove is a preset angle b. The preset angle a and the preset angle b satisfy the relationship: a > b.

[0010] According to some embodiments of the present invention, the first sealing ring is provided with a first mating surface on the side away from the hard gasket ring and the second sealing ring is provided with a first mating surface on the side away from the first extension. The valve seat and the hard gasket ring are each provided with a second mating surface that mates with the first mating surface. The first mating surface and the second mating surface are both frustoconical structures.

[0011] According to some embodiments of the present invention, the half-apex angle corresponding to the first mating surface is a preset angle c, and the half-apex angle corresponding to the second mating surface is a preset angle d. The preset angle c and the preset angle d satisfy the relationship: d > c.

[0012] According to some embodiments of the present invention, the elastic element is a compression spring. The elastic element is provided with a plurality of springs and is evenly distributed around the axis of the pressure ring. The pressure ring is provided with a receiving hole for the elastic element to be partially inserted. One end of the elastic element abuts against the valve body assembly, and the other end extends into the receiving hole and abuts against the pressure ring.

[0013] According to some embodiments of the present invention, the valve body assembly has an annular stepped portion on the inner wall of the medium channel, the pressure ring has a corresponding second extension portion, the end of the elastic member abuts against the annular stepped portion, and the second extension portion is annular and cooperates with the inner wall of the annular stepped portion to cover the elastic member.

[0014] According to some embodiments of the present invention, the valve body assembly is provided with a purge channel, which can connect the valve core cavity with the external environment. A sealing plug is provided at the purge channel, which is detachably connected to the valve body assembly and can block the purge channel.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0017] Figure 1 This is a schematic diagram of the high-cleanliness, high-pressure resistant soft-seal ball valve according to an embodiment of the present invention;

[0018] Figure 2 for Figure 1 Exploded view of the structure of a medium-to-high cleanliness, high-pressure resistant soft-seal ball valve;

[0019] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of a medium-to-high cleanliness, high-pressure resistant soft-seal ball valve;

[0020] Figure 4 for Figure 3 An enlarged schematic diagram of part A in the middle;

[0021] Figure 5 for Figure 4 Enlarged schematic diagram of part B.

[0022] Figure label:

[0023] Valve body assembly 100, valve core cavity 101, medium passage 102, purge passage 103, valve body 110, annular stepped portion 111, top valve cover 120, side valve cover 130, sealing plug 140;

[0024] Ball core 210, valve stem 220;

[0025] Annular groove 301, annular space 302, annular groove 303, first mating surface 304, second mating surface 305, receiving hole 306, valve seat 310, rigid housing 311, soft sealing body 312, pressure ring 320, first extension 321, second extension 322, elastic element 330, first sealing ring 340, rigid gasket ring 350, annular protrusion 351, second sealing ring 360, preset angle a, preset angle b, preset angle c, preset angle d. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] In the description of this utility model, it should be understood that if directional descriptions are involved, such as up, down, front, back, left, right, etc., indicating the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings, it is only for the convenience of describing this utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0028] In the description of this utility model, if words such as several, greater than, less than, exceeding, above, below, or within appear, several means one or more, multiple means two or more, greater than, less than, exceeding, etc. are understood to exclude the number itself, and above, below, or within are understood to include the number itself.

[0029] If the terms "first" and "second" are used only to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0031] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 A high-cleanliness, high-pressure resistant soft-seal ball valve includes a valve body assembly 100, a ball core 210, and a soft-seal structure. The valve body assembly 100 has a valve core cavity 101 and medium channels 102 located on both sides of the valve core cavity 101, the medium channels 102 communicating with the valve core cavity 101. The ball core 210 is rotatably disposed in the valve core cavity 101. The soft-seal structure is located between the medium channels 102 and the valve core cavity 101 and includes a valve seat 310, a pressure ring 320, and an elastic element 330. The seat 310 is annular and has a rigid shell 311 and a soft sealing body 312. The rigid shell 311 is provided with an annular groove 301. The annular groove 301 has an open structure on the side facing the ball core 210. The soft sealing body 312 is disposed in the annular groove 301 and partially extends out from the open structure of the annular groove 301. The elastic member 330 acts on the valve seat 310 through the pressure ring 320, so that the part of the soft sealing body 312 extending out from the open structure of the annular groove 301 abuts against the ball core 210.

[0032] Understandably, such as Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the valve body assembly 100 includes a valve body 110, a top valve cover 120, and a side valve cover 130. The top valve cover 120 is located on the upper side of the valve body 110, and the side valve cover 130 is located on the right side of the valve body 110. The three are connected and fixed by bolts. The valve body 110 and the side valve cover 130 define a valve core cavity 101. Medium channels 102 are provided on both the left and right sides of the valve core cavity 101. The medium channels 102 communicate with the valve core cavity 101. The ball core 210 is rotatably disposed in the valve core cavity 101. A valve stem 220 is rotatably disposed on the top valve cover 120. The valve stem 220 passes through the top valve cover 120, and its lower end extends into the valve core cavity 101 and connects with the ball core 210 to drive the ball core 210 to rotate. In use, the medium is input through the medium channel 102 on one side of the valve body assembly 100. By rotating the ball core 210, the opening and closing of the ball valve is controlled, thereby controlling the medium output of the medium channel 102 on the other side. A soft sealing structure is provided between the medium channel 102 and the valve core cavity 101. The elastic element 330 acts on the valve seat 310 through the pressure ring 320, so that the soft sealing body 312 of the valve seat 310 abuts against the ball core 210 to achieve a seal. By setting the soft sealing body 312 in the annular groove 301 of the rigid shell 311 and the part that abuts against the ball core 210 protruding from the opening structure of the annular groove 301, the rigid shell 311 can partially cover the soft sealing body 312, protect the soft sealing body 312, reduce the impact of the medium pressure on it, improve the high pressure resistance of the valve seat 310, reduce the possibility of deformation of the valve seat 310 due to high pressure medium, ensure sealing performance, and enable the ball valve to be used in high pressure medium conditions, thus improving its adaptability.

[0033] In practical applications, the specific structure of the valve body assembly 100 and the ball core 210 can be set according to the actual needs. The specific structural form of the soft seal structure will not be described in detail here, but will be explained in detail below.

[0034] In some embodiments, the soft sealing structure further includes a graphite sealing ring. The pressure ring 320 has a first extension 321 extending toward the valve seat 310 on the side facing the valve seat 310. The first extension 321 is annular. An annular space 302 is defined between the inner wall of the medium channel 102, the first extension 321 and the valve seat 310. The graphite sealing ring is sleeved on the valve seat 310 and located in the annular space 302. The first extension 321 can squeeze the graphite sealing ring under the action of the elastic member 330, so that the graphite sealing ring seals the gap between the inner wall of the medium channel 102 and the valve seat 310.

[0035] Understandably, such as Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, the first extension 321 is annular and located on the side of the pressure ring 320 facing the valve seat 310. An annular space 302 is defined between the inner wall of the medium channel 102, the first extension 321, and the valve seat 310. A graphite sealing ring is fitted onto the valve seat 310 and located within the annular space 302. The first extension 321 compresses the graphite sealing ring, causing it to deform and abut against both the inner wall of the sealing medium channel 102 and the outer wall of the valve seat 310, thereby sealing the gap between them. This improves sealing performance and facilitates use. In practical applications, the first extension 321 and the graphite sealing ring can be adjusted according to actual usage requirements.

[0036] In some embodiments, the soft sealing structure further includes a hard gasket 350. Two graphite sealing rings are provided, namely a first sealing ring 340 and a second sealing ring 360. The hard gasket 350 is sleeved on the valve seat 310 and sandwiched between the first sealing ring 340 and the second sealing ring 360. The second sealing ring 360 is sandwiched between the first extension 321 and the hard gasket 350.

[0037] Understandably, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, in the two soft sealing structures on the left and right sides of the valve core cavity 101, each soft sealing structure includes two graphite sealing rings, namely a first sealing ring 340 and a second sealing ring 360. A hard gasket 350 is sleeved on the valve seat 310 and sandwiched between the first sealing ring 340 and the second sealing ring 360. The first sealing ring 340 is located on the side of the hard gasket 350 closer to the valve core cavity 101, and the second sealing ring 360 is located on the side of the hard gasket 350 away from the valve core cavity 101. By setting multiple graphite sealing rings with a hard gasket 350 sandwiched in the middle, multiple seals can be formed, further improving the sealing performance and facilitating use. In practical applications, the specific structure of the first sealing ring 340, the second sealing ring 360, and the hard gasket 350 can be set according to actual usage requirements.

[0038] In some embodiments, the first extension 321 is provided with annular protrusions 351 on the side facing the second sealing ring 360 and the rigid gasket 350 is provided with annular grooves 303 on the side facing the first sealing ring 340, corresponding to the side of the first sealing ring 340 facing the rigid gasket 350 and the side of the second sealing ring 360 facing the first extension 321. The outer contour of the single-sided cross section of the annular protrusion 351 is shaped like a side "V", and the inner contour of the single-sided cross section of the annular groove 303 is shaped like a side "V". The annular protrusion 351 can be inserted into the annular groove 303.

[0039] Understandably, such as Figure 3 , Figure 4 and Figure 5As shown, the first sealing ring 340 and the second sealing ring 360 have similar structures. Both have annular grooves 303 on the side away from the valve core cavity 101. Correspondingly, the first extension 321 and the hard gasket ring 350 both have annular protrusions 351 on the side near the valve core cavity 101. One side of the annular protrusion 351 ( Figure 4 and Figure 5 The lower section shown has a side "V" shaped profile, and the annular groove 303 has one side ( Figure 4 and Figure 5 The cross-section shown (bottom side) has a side "V" shape. An annular protrusion 351 is inserted into an annular groove 303. When the graphite sealing ring is compressed, the inner and outer surfaces of the annular groove 303 are subjected to inward and outward pressures, respectively. This ensures that the inner annular surface of the graphite sealing ring near the annular protrusion 351 abuts well against the valve seat 310, and the outer annular surface of the graphite sealing ring near the annular protrusion 351 abuts well against the valve body assembly 100, achieving a good sealing effect. In practical applications, the annular protrusion 351 and the annular groove 303 can be adjusted according to actual usage requirements.

[0040] Furthermore, the included angle corresponding to the V-shaped outer contour of the single-sided section of the annular protrusion 351 is a preset angle a, and the included angle corresponding to the V-shaped inner contour of the single-sided section of the annular groove 303 is a preset angle b. The preset angle a and the preset angle b satisfy the relationship: a > b.

[0041] Understandably, such as Figure 4 and Figure 5 As shown, the preset angles a and b satisfy the relationship: a > b, meaning preset angle a is greater than preset angle b. The "V" angle corresponding to the outer contour of one side of the annular protrusion 351 is equal to the "V" angle corresponding to the inner contour of the "V" shape of one side of the annular groove 303. Therefore, when the annular protrusion 351 is inserted into the annular groove 303, it will intensify the deformation of the inner and outer sides of the annular groove 303, further improving the sealing and contact effect between the graphite sealing ring and the valve body assembly 100 and the valve seat 310, making it easier to use. In practical applications, preset angle a can be slightly larger than preset angle b. The specific angle values ​​of preset angles a and b can be set according to actual usage needs.

[0042] In some embodiments, the first sealing ring 340 is provided with a first mating surface 304 on the side away from the hard gasket ring 350 and the second sealing ring 360 is provided with a side away from the first extension 321. The valve seat 310 and the hard gasket ring 350 are each provided with a second mating surface 305 that mates with the first mating surface 304. The first mating surface 304 and the second mating surface 305 are both frustoconical structures.

[0043] Understandably, such as Figure 4 and Figure 5As shown, by setting the first mating surface 304 and the second mating surface 305 of the frustoconical structure, the first sealing ring 340 and the valve seat 310, as well as the second sealing ring 360 and the hard gasket ring 350, are in contact through the conical surface. On the one hand, this increases the sealing contact area. On the other hand, the conical surface contact causes the side of the graphite sealing ring near the valve core cavity 101 to tend to open outward when the reaction force of the valve seat 310 and the hard gasket ring 350 is applied to the graphite sealing ring, thus better sealing and abutting with the valve body assembly 100 and improving the sealing performance.

[0044] Furthermore, the half-apex angle corresponding to the first mating surface 304 is a preset angle c, and the half-apex angle corresponding to the second mating surface 305 is a preset angle d. The preset angle c and the preset angle d satisfy the relationship: d > c.

[0045] Understandably, such as Figure 4 and Figure 5 As shown, the preset angles c and d satisfy the relationship: d > c, meaning the preset angle d is greater than the preset angle c. Therefore, when the first mating surface 304 and the second mating surface 305 abut, this angular deviation will cause the graphite sealing ring near the valve core cavity 101 to tend to flip outwards, thereby intensifying the deformation of the graphite sealing ring and further improving the sealing effect between the graphite sealing ring and the valve body assembly 100, facilitating its use. In practical applications, the preset angle d can be slightly larger than the preset angle c. The specific angle values ​​of the preset angles c and d can be set according to actual usage needs.

[0046] In some embodiments, the elastic element 330 is a compression spring. The elastic element 330 is provided with a plurality of springs and is evenly distributed around the axis of the pressure ring 320. The pressure ring 320 is provided with a receiving hole 306 for the elastic element 330 to be partially inserted. One end of the elastic element 330 abuts against the valve body assembly 100, and the other end extends into the receiving hole 306 and abuts against the pressure ring 320.

[0047] Understandably, such as Figure 2 , Figure 3 and Figure 4 As shown, the elastic element 330 is a compression spring, which has multiple springs evenly spaced around the axis of the pressure ring 320. One end of the elastic element 330 abuts against the valve body assembly 100, and the other end extends into the receiving hole 306 and abuts against the pressure ring 320. Its structure is simple and convenient for production, assembly, and application. In practical applications, the elastic element 330 can also be a disc spring, which can be set according to the actual needs of the application.

[0048] In some embodiments, the valve body assembly 100 is provided with an annular stepped portion 111 on the inner wall of the medium channel 102, and the pressure ring 320 is provided with a corresponding second extension portion 322. The end of the elastic member 330 abuts against the annular stepped portion 111, and the second extension portion 322 is annular and cooperates with the inner wall of the annular stepped portion 111 to cover the elastic member 330.

[0049] Understandably, such as Figure 3 and Figure 4 As shown, the pressure ring 320 has a second extension 322 on the side away from the valve core cavity 101. The inner wall of the medium channel 102 is provided with an annular stepped portion 111. One end of the elastic member 330 extends into the receiving hole 306, and the other end abuts against the annular stepped portion 111. The second extension 322 is annular and cooperates with the inner wall of the annular stepped portion 111, thereby blocking the elastic member 330. This helps to prevent the medium from entering the position of the elastic member 330, reducing the impact of the medium on the elastic member 330, and ensuring the sealing effect. In actual applications, the second extension 322 and the annular stepped portion 111 can be set according to the actual needs of use.

[0050] In some embodiments, the valve body assembly 100 is provided with a purge channel 103, which can connect the valve core cavity 101 with the external environment. A sealing plug 140 is provided at the purge channel 103, which is detachably connected to the valve body assembly 100 and can block the purge channel 103.

[0051] Understandably, such as Figure 2 , Figure 3 and Figure 4 As shown, the purge channel 103 runs through the inner and outer sides of the valve body 110, allowing the valve core cavity 101 to connect to the external environment through the purge channel 103. During normal use, the sealing plug 140 seals the purge channel 103. When used with particulate media, some particulate media will exist between the inner wall of the valve core cavity 101 and the outer wall of the ball core 210. Moreover, as the usage time increases, the amount of particulate media between the inner wall of the valve core cavity 101 and the outer wall of the ball core 210 will gradually increase. This increase will create resistance to the rotation of the ball core 210, resulting in an increase in the torque required for rotation. At this time, the sealing plug 140 can be removed from the purge channel 103. Then, by connecting the suction pipe to the purge channel 103, some particulate media between the inner wall of the valve core cavity 101 and the outer wall of the ball core 210 can be suctioned out, thereby reducing the rotational resistance of the ball core 210, facilitating the operation of the ball core 210 rotation, and making it easier to use. In practical applications, the detachable connection between the sealing plug 140 and the valve body 110 can be achieved through a threaded structure or other detachable structure, which can be set according to the actual needs of use.

[0052] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A high-cleanliness, high-pressure resistant soft-seal ball valve, characterized in that, include: A valve body assembly, wherein the valve body assembly is provided with a valve core cavity and medium channels disposed on both sides of the valve core cavity, the medium channels communicating with the valve core cavity; A ball core, which is rotatably disposed in the valve core cavity; A soft-seal structure is provided between the medium channel and the valve core cavity and includes a valve seat, a pressure ring, and an elastic element. The valve seat is annular and has a rigid shell and a soft-seal body. The rigid shell has an annular groove, and the side of the annular groove facing the ball core is open. The soft-seal body is disposed in the annular groove and partially extends out from the opening of the annular groove. The elastic element acts on the valve seat through the pressure ring, so that the portion of the soft-seal body extending out from the opening of the annular groove abuts against the ball core.

2. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 1, characterized in that, The soft sealing structure further includes a graphite sealing ring. The pressure ring has a first extension extending toward the valve seat on the side facing the valve seat. The first extension is annular. An annular space is defined between the inner wall of the medium channel, the first extension, and the valve seat. The graphite sealing ring is sleeved on the valve seat and located in the annular space. The first extension can squeeze the graphite sealing ring under the action of the elastic member, so that the graphite sealing ring seals the gap between the valve seat and the inner wall of the medium channel.

3. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 2, characterized in that, The soft sealing structure also includes a hard gasket ring. There are two graphite sealing rings, namely a first sealing ring and a second sealing ring. The hard gasket ring is sleeved on the valve seat and sandwiched between the first sealing ring and the second sealing ring. The second sealing ring is sandwiched between the first extension and the hard gasket ring.

4. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 3, characterized in that, The first extension has an annular protrusion on the side facing the second sealing ring, and the rigid gasket has an annular groove on the side facing the first sealing ring. The first sealing ring has an annular groove on the side facing the rigid gasket, and the second sealing ring has an annular groove on the side facing the first extension. The outer contour of the single-sided cross-section of the annular protrusion is shaped like a side "V", and the inner contour of the single-sided cross-section of the annular groove is shaped like a side "V". The annular protrusion can be inserted into the annular groove.

5. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 4, characterized in that, The included angle corresponding to the V-shaped outer contour of the single-sided cross section of the annular protrusion is a preset angle a, and the included angle corresponding to the V-shaped inner contour of the single-sided cross section of the annular groove is a preset angle b. The preset angles a and b satisfy the relationship: a > b.

6. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 3, characterized in that, The first sealing ring is provided with a first mating surface on the side away from the hard gasket ring and the second sealing ring is provided with a first mating surface on the side away from the first extension. The valve seat and the hard gasket ring are respectively provided with a second mating surface that mates with the first mating surface. The first mating surface and the second mating surface are both frustoconical structures.

7. The high-purity, high-pressure soft-seal ball valve of claim 6, wherein, The half-apex angle corresponding to the first mating surface is a preset angle c, and the half-apex angle corresponding to the second mating surface is a preset angle d. The preset angle c and the preset angle d satisfy the relationship: d > c.

8. The high-purity, high-pressure soft-seal ball valve of claim 1, wherein, The elastic element is a compression spring. The elastic element is provided in multiple portions and is evenly distributed around the axis of the pressure ring. The pressure ring is provided with a receiving hole for the elastic element to be partially inserted. One end of the elastic element abuts against the valve body assembly, and the other end extends into the receiving hole and abuts against the pressure ring.

9. The high-purity, high-pressure soft-seal ball valve of claim 8, wherein, The valve body assembly has an annular stepped portion on the inner wall of the medium channel, and the pressure ring has a corresponding second extension portion. The end of the elastic member abuts against the annular stepped portion. The second extension portion is annular and cooperates with the inner wall of the annular stepped portion to cover the elastic member.

10. The high-cleanliness, high-pressure resistant soft-seal ball valve according to claim 1, characterized in that, The valve body assembly is provided with a purge channel, which can connect the valve core cavity with the external environment. A sealing plug is provided at the purge channel, which is detachably connected to the valve body assembly and can block the purge channel.

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