An active sealing structure and a ball valve having the same

Abstract

The present invention provides a movable sealing structure and a ball valve having the same, wherein the movable sealing structure comprises: a valve seat movably mounted on a valve cover, and a movable sealing ring movably mounted on a valve ball, wherein the valve seat has a valve seat sealing surface, and the movable sealing ring has a valve ball sealing surface, and when the valve seat sealing surface is tightly combined with the valve ball sealing surface, sealing is achieved. The movable sealing structure of the present invention has a movable installation arrangement of the valve seat, which can flexibly compensate for the pressure reduction between the valve seat sealing surface and the valve ball sealing surface after the sealing surface is worn, and avoid poor sealing after slight wear; the valve ball sealing surface is arranged on the movable sealing ring, and the movable sealing ring is movably and rotatably mounted on the valve ball. When the valve ball is assembled, if the valve seat sealing surface and the valve ball sealing surface are not tightly fitted due to inaccurate alignment, the movable sealing ring can be loosened and rotated, and the valve seat sealing surface and the valve ball sealing surface can be adjusted to achieve precise alignment, and then the movable sealing ring can be re-fixed, thereby improving assembly efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of ball valves, and particularly to a movable sealing structure and a ball valve having the same. Background Art

[0002] The ball valve is one of the valves with relatively wide applications. It has a simple structure, reliable sealing, and convenient maintenance, and is widely used in fields such as petroleum, chemical industry, metallurgy, light textile, food, atomic energy, and aviation. The ball valve has an operation of rotating 90°. The plug body is a sphere, and there is a circular through-hole or passage passing through its axis. It is mainly used in pipelines to cut off, distribute, and change the flow direction of the medium. It only needs a 90° rotation operation and a very small rotational torque to close tightly.

[0003] The sealing of a conventional ball valve relies on the precise extrusion sealing between the valve seat sealing surface and the sphere sealing surface. This requires very high machining accuracy and installation accuracy for both the valve seat sealing surface and the sphere sealing surface. Once there are slight deviations in machining or installation, there may be bias pressure, affecting the sealing effect, and in severe cases, it may lead to sealing failure. In the prior art, the valve seat is usually fixedly installed on the valve cover. When the ball valve is closed, the spherical surface of the valve ball is in extrusion contact with the valve seat sealing surface of the valve seat to achieve sealing. This requires very high installation accuracy for the valve seat and usually involves multiple fine-tuning processes. Moreover, even if the installation accuracy reaches the requirement at the beginning, after a certain period of use, there may still be bias wear, resulting in uneven sealing pressure between the valve seat sealing surface and the spherical surface, and further leading to a reduction in sealing strength. In severe cases, it can even cause sealing failure. In addition, for the ball valve in the prior art, both the valve seat sealing surface and the sphere sealing surface are fixedly arranged. Once the sealing fails due to wear or the like, the entire ball valve needs to be replaced, resulting in a high cost.

[0004] Chinese Patent Document CN108980400B discloses an eccentric ball valve. Its valve seat is installed on the valve cover in a slightly movable manner through an adjustable installation structure, and there is a gap between the outer circumferential surface of the valve seat and the valve cover. When the valve ball rotates under the drive of the operating mechanism to gradually make the valve ball sealing surface and the valve seat sealing surface in extrusion contact, the valve seat can make a slight movement along its circumferential direction, so that the valve ball sealing surface and the valve seat sealing surface can automatically adjust and align, thereby achieving a uniformly pressured seal. Although the technical solution in the above patent document can solve the problem of slight installation deviations, it has relatively high production accuracy requirements.

[0005] Therefore, how to design a new type of ball valve that can both solve the technical problem of multiple fine-tuning required during the installation process and reduce the valve replacement cost is a technical problem that has not been solved in the prior art. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the technical defects of the ball valve in the prior art. Although the ball valve can solve the problem of slight deviation during installation and does not require multiple adjustments, it has high requirements for production accuracy. Moreover, once the valve seat sealing surface fails due to wear, the entire ball valve needs to be replaced, resulting in high replacement costs. Thus, an active sealing structure applied to the ball valve is provided.

[0007] The present invention also provides a ball valve having the above active sealing structure.

[0008] For this purpose, the present invention provides an active sealing structure, including:

[0009] A valve seat, adapted to be movably installed on the valve cover, having a valve seat sealing surface, and the valve seat sealing surface is an eccentric sealing surface;

[0010] An active sealing ring, adapted to be movably and rotatably installed on the valve ball, having a valve ball sealing surface, and the valve ball sealing surface is an eccentric sealing surface capable of cooperating with the valve seat sealing surface for sealing;

[0011] After the valve seat sealing surface and the valve ball sealing surface are closely attached, sealing is achieved.

[0012] As a preferred solution, the valve seat includes a cylindrical main body portion, an annular portion provided at one end of the cylindrical main body portion, and a sealing portion located at the connection position between the cylindrical main body portion and the annular portion. The valve seat sealing surface is provided at a position on the side of the sealing portion facing the valve ball; a depression is formed at the position of the valve cover for installing the valve seat, and the outer wall of the valve seat is attached to the inner wall of the depression.

[0013] As a preferred solution, the active sealing structure further includes a valve seat fixing structure. The valve seat fixing structure includes an annular baffle having a through hole, adapted to be fixed to the valve cover by bolts, and a limiting cavity is formed between a part of the annular baffle and the valve cover;

[0014] An annular protrusion is provided on the outer periphery of the annular portion, and the annular protrusion extends into the limiting cavity and is limited by the limiting cavity.

[0015] As a preferred solution, on the side of the cylindrical main body portion facing the valve cover, a first gap and a second gap are formed. The width of the second gap is greater than that of the first gap. A valve seat sealing ring is installed inside the first gap, and a valve seat bushing is installed inside the second gap. One end of the valve seat bushing is fitted and inserted into the first gap and squeezes the valve seat sealing ring towards the valve cover direction. A valve seat spring is installed at the other end of the valve seat bushing, and there is an active gap between the valve seat bushing and the side wall of the second gap close to the first gap.

[0016] As a preferred solution, it further includes an annular groove, which is provided on the inner wall of the valve cover located outside the valve seat bushing. A graphite gasket is provided inside the annular groove, and the part of the graphite gasket protruding from the annular groove is in close contact with the outer wall of the cylindrical main body.

[0017] As a preferred solution, the movable sealing ring has a fixed state and a rotatable state; when in the fixed state, the movable sealing ring and the valve ball are fixed as a whole; when in the rotatable state, under the action of an external force, the movable sealing ring can rotate relative to the valve ball, thereby changing the relative position between the sealing surface of the valve ball and the sealing surface of the valve seat.

[0018] As a preferred solution, the movable sealing ring includes an annular main body. A rotating hole is provided in the middle of the annular main body, and the annular sealing surface is provided on the periphery of the annular main body; the rotating hole is a through hole.

[0019] As a preferred solution, the valve ball is provided with:

[0020] A first plane, formed at one end of the valve ball for sealing;

[0021] A first stepped column, formed on the first plane and perpendicular to the first plane; the first stepped column is adapted to be rotatably sleeved by the rotating hole, and the height of the first stepped column ≤ the thickness of the movable sealing ring;

[0022] A gland, detachably and fixedly installed on the valve ball, for fixing the movable sealing ring sleeved on the first stepped column.

[0023] As a preferred solution, a second plane is provided on the top surface of the first stepped column, and a second stepped column is formed on the second plane. After the gland is sleeved on the second stepped column, it is fixedly installed on the second plane through bolts.

[0024] The present invention also provides a ball valve, which includes a valve body, a valve ball installed inside the valve body through a valve stem, a valve cover installed on the valve body, and a valve seat installed inside the valve cover;

[0025] It further includes a movable sealing structure installed on the valve seat and the valve ball, and the movable sealing structure is the movable sealing structure described in any one of the above.

[0026] The technical solution provided by the present invention has the following advantages:

[0027] 1. The movable sealing structure of the present invention includes a valve seat movably installed on the valve cover and a movable sealing ring movably installed on the valve ball. The valve seat has a valve seat sealing surface, and the movable sealing ring has a valve ball sealing surface. When the valve seat sealing surface and the valve ball sealing surface are closely combined, sealing is achieved. In the movable sealing structure of the present invention, the valve seat is movably installed. First, it can flexibly compensate for the decrease in pressure between the valve seat sealing surface and the valve ball sealing surface after wear of the sealing surface, avoiding unsealing after slight wear. Second, when the valve seat sealing surface needs to be replaced due to wear, only the relatively small-sized valve seat needs to be replaced, and the equipment replacement cost is low. The valve ball sealing surface is arranged on the movable sealing ring, and the movable sealing ring is movably and rotatably installed on the valve ball. When assembling the valve ball, if the valve seat sealing surface and the valve ball sealing surface do not fit tightly due to inaccurate alignment, the movable sealing ring can be loosened, and by rotating the movable sealing ring, the valve seat sealing surface and the valve ball sealing surface can be quickly adjusted to achieve precise alignment. After adjustment, the movable sealing ring is fixed again, thereby greatly improving the assembly efficiency.

[0028] 2. In the movable sealing structure of the present invention, a depression is formed at the position of the valve cover for installing the valve seat, and the outer wall of the valve seat is attached to the inner wall of the depression, so that the valve seat can only move along the direction of the medium flow and will not undergo radial movement.

[0029] 3. The movable sealing structure of the present invention further includes a valve seat fixing structure. The valve seat fixing structure includes an annular baffle, the annular baffle is fixed on the valve cover by bolts, and a limiting cavity is formed between a part of the annular baffle and the valve cover; an annular protrusion is provided on the outer periphery of the annular part, and the annular protrusion extends into the limiting cavity and is limited by the limiting cavity, so that the valve seat can only perform a certain degree of telescopic movement along the direction of the medium flow.

[0030] 4. In the movable sealing structure of the present invention, on the side of the cylindrical main body facing the valve cover, a first gap and a second gap are formed. A trapezoidal valve seat sealing ring is installed inside the first gap, and a valve seat pressing sleeve is installed inside the second gap. One end of the valve seat pressing sleeve fits and inserts into the first gap and presses the valve seat sealing ring towards the valve cover direction. A valve seat spring is installed at the other end of the valve seat pressing sleeve. The valve seat spring is used to drive the valve seat pressing sleeve and then drive the valve seat towards the valve ball direction, so as to tightly press the valve seat sealing surface and the valve ball sealing surface. And even when the sealing surface has slight wear, under the pressure of the spring, the valve seat sealing surface and the valve ball sealing surface can still achieve extrusion sealing.

[0031] 5. The movable sealing structure of the present invention further includes an annular groove, a graphite gasket is provided inside the annular groove, and the part of the graphite gasket extending out of the annular groove is in contact with the outer wall of the cylindrical main body to achieve sealing and prevent the medium from entering the valve seat pressing sleeve.

[0032] 6. The movable seal structure of the present invention: when the movable seal ring is in a fixed state, the movable seal ring is fixed integrally with the valve ball, and the movable seal ring rotates with the valve ball to open or cut off the flow passage; when the movable seal ring is in a rotatable state, under the action of an external force, the sealing surface of the valve ball can rotate relative to the sealing surface of the valve seat; when the sealing surface of the valve seat and the sealing surface of the valve ball cannot be in close contact to achieve sealing during assembly, the movable seal ring can be loosened to a rotatable state, and the movable seal ring is gradually rotated until the sealing surface of the valve ball is in close contact with the sealing surface of the valve seat for sealing. At this time, the movable seal ring is fixed on the valve ball, and precise assembly of the valve ball can be achieved. The movable seal structure of the present invention can solve the technical problem that fine deviations are likely to occur during installation and multiple fine adjustments are required.

[0033] 7. The movable seal structure of the present invention: the movable seal ring includes an annular main body. A rotation hole is provided in the middle of the annular main body, and a valve ball sealing surface is provided on the periphery of the annular main body; the movable seal ring is installed on the valve ball through the rotation hole, and when adjustment is required, the movable seal ring rotates through the position of the rotation hole.

[0034] 8. The movable seal structure of the present invention: the valve ball is provided with a first plane and a first stepped column. The movable seal ring is sleeved on the first stepped column and is fixedly installed on the valve ball using a gland, and the movable seal ring sleeved on the first stepped column is squeezed and fixed.

[0035] 9. The movable seal structure of the present invention: the top surface of the first stepped column is provided with a second plane, and a second stepped column is formed on the second plane. After the gland is sleeved on the second stepped column, it is fixedly installed on the second plane through bolts; the design of the second stepped column and the second plane makes it more convenient to fix the gland.

[0036] 10. The present invention also provides a ball valve, which includes a valve body, a valve stem, a valve ball, a valve seat, a valve cover, etc., and also includes a movable seal structure installed between the valve seat and the valve ball. The movable seal structure therein is the above-mentioned movable seal structure. Due to the adoption of the above-mentioned movable seal structure, it naturally has all the advantages brought about by the adoption of the above-mentioned valve ball structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the prior art or the specific embodiments of the present invention, the following briefly introduces the drawings used in the description of the prior art or the specific embodiments.

[0038] Figure 1 It is a schematic diagram of the overall structure of the valve ball of the present invention.

[0039] Figure 2 It is Figure 1 An enlarged schematic diagram of the structure of part A in

[0040] Reference numerals: 100, valve seat; 101, valve seat sealing surface; 110, cylindrical main body; 111, first gap; 112, second gap; 113, first chamfered structure; 120, annular portion; 121, annular protrusion; 130, sealing portion; 140, annular baffle; 141, limiting cavity; 150, valve seat sealing ring; 160, valve seat pressing sleeve; 170, valve seat spring; 180, movable gap; 190, annular Groove; 191, graphite gasket; 200, movable sealing ring; 201, valve ball sealing surface; 210, annular body; 211, rotating hole; 300, valve ball; 301, first plane; 302, first step column; 303, pressure cover; 304, second plane; 305, second step column; 306, bolt; 400, valve cover; 401, end face; 402, second chamfered structure; 500, valve stem; 600, valve body. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings. Example 1

[0042] This embodiment provides a movable sealing structure for an eccentric ball valve, such as Figure 2 As shown, it includes: a valve seat 100, which is suitable for being movably mounted on a valve cover 400, and has a valve seat sealing surface 101, and the valve seat sealing surface 101 is an eccentric sealing surface; a movable sealing ring 200, which is suitable for being movably and rotatably mounted on a valve ball 300, and has a valve ball sealing surface 201, and the valve ball sealing surface 201 is an eccentric sealing surface that can cooperate with the valve seat sealing surface 101 for sealing; after the valve seat sealing surface 101 and the valve ball sealing surface 201 are tightly fitted, sealing is achieved.

[0043] The movable sealing structure of this embodiment has a movably installed valve seat 100. Firstly, it can flexibly compensate for the pressure reduction between the valve seat sealing surface 101 and the valve ball sealing surface 201 after the sealing surface is worn, thereby avoiding poor sealing after slight wear. Secondly, when the valve seat sealing surface 101 needs to be replaced after wear, it is only necessary to replace the valve seat 100 with a smaller volume, and the equipment replacement cost is low. The valve ball sealing surface 201 is arranged on the movable sealing ring 200, and the movable sealing ring 200 is movably and rotatably installed on the valve ball 300. When the valve ball 300 is assembled, if the valve seat sealing surface 101 and the valve ball sealing surface 201 are not tightly fitted due to inaccurate alignment, the movable sealing ring 200 can be loosened. By rotating the movable sealing ring 200, the valve seat sealing surface 101 and the valve ball sealing surface 201 can be quickly adjusted to achieve precise alignment. After the adjustment, the movable sealing ring 200 can be re-fixed, thereby greatly improving the assembly efficiency.

[0044] The valve seat 100 includes a cylindrical main body portion 110, an annular portion 120 provided at one end of the cylindrical main body portion 110, and a sealing portion 130 located at the connection position of the cylindrical main body portion 110 and the annular portion 120. The valve seat sealing surface 101 is provided at a position on the side of the sealing portion 130 facing the valve ball 300; a recess is formed at the position of the valve cover 400 for mounting the valve seat 100, and the outer wall of the valve seat 100 is attached to the inner wall of the recess.

[0045] The outer wall of the valve seat 100 is attached to the inner wall of the recess, so that the valve seat 100 can only move in the direction of the medium flow (i.e., Figure 2 the left - right direction in the figure), and will not move radially.

[0046] The movable sealing structure further includes a valve seat fixing structure. The valve seat fixing structure includes an annular baffle 140 having a through - hole and adapted to be fixed to the valve cover 400 by bolts. A limiting cavity 141 is formed between a part of the annular baffle 140 and the valve cover 400.

[0047] An annular protrusion 121 is provided on the outer periphery of the annular portion 120. The annular protrusion 121 extends into the limiting cavity 141 and is limited by the limiting cavity 141, so that the valve seat 100 can only perform a certain degree of telescopic movement in the direction of the medium flow.

[0048] On the side of the cylindrical main body portion 110 facing the valve cover 400, a first gap 111 and a second gap 112 are formed. The width of the second gap 112 is greater than that of the first gap 111. A valve seat sealing ring 150 is installed inside the first gap 111, and a valve seat bushing 160 is installed inside the second gap 112. One end of the valve seat bushing 160 fits and inserts into the first gap 111 and squeezes the valve seat sealing ring 150 in the direction of the valve cover 400. A valve seat spring 170 is installed at the other end of the valve seat bushing 160. There is a movable gap 180 between the valve seat bushing 160 and the side wall of the second gap 112 close to the first gap 111.

[0049] The valve seat spring 170 is used to drive the valve seat 100 in the direction of the valve ball 300 by driving the valve seat bushing 160, so as to squeeze the valve seat sealing surface 101 and the valve ball sealing surface 201 tightly. And even when the sealing surface (any one of the above two sealing surfaces) is slightly worn, under the pressure of the spring, the valve seat sealing surface 101 and the valve ball sealing surface 201 can still achieve extrusion sealing.

[0050] It further includes an annular groove 190, which is arranged on the inner wall of the valve cover 400 located outside the valve seat bushing 160. A graphite gasket 191 is arranged inside the annular groove 190. The part of the graphite gasket 191 extending out of the annular groove 190 is in close contact with the outer wall of the cylindrical main body 110 to achieve sealing and prevent the medium from entering the inside of the valve seat bushing 160.

[0051] A first chamfer structure 113 is formed at the end of the cylindrical main body 110. When installing the valve seat 100, the first chamfer 113 structure can avoid touching the graphite gasket 191, ensure the correct installation position of the graphite gasket 191, and ensure tight sealing.

[0052] The valve cover 400 has an end face 401 opposite to the cylindrical main body part 110. The end face 401 has a certain distance from the top end of the cylindrical main body part 110, and a second chamfer structure 402 is formed at the position of the end face 401.

[0053] There is a certain distance between the end face 401 and the top end of the cylindrical main body part 110, leaving space for the movement of the valve seat 100; when the medium enters the space between the end face 401 and the top end of the cylindrical main body part 110, the setting of the second chamfer 402 can prevent the medium from staying in this space.

[0054] In this embodiment, the movable sealing ring 200 has a fixed state and a rotatable state; when in the fixed state, the movable sealing ring 200 and the valve ball 300 are fixed as a whole; when in the rotatable state, under the action of an external force, the movable sealing ring 200 can rotate relative to the valve ball 300, thereby changing the relative position between the valve ball sealing surface 201 and the valve seat sealing surface 101.

[0055] When the valve seat sealing surface 101 and the valve ball sealing surface 201 cannot be in close contact to achieve sealing during assembly, the movable sealing ring 200 can be loosened to the rotatable state, and the movable sealing ring 200 is gradually rotated until the valve ball sealing surface 201 and the valve seat sealing surface 101 are in close contact and sealed. At this time, the movable sealing ring 200 is fixed on the valve ball 300, and the precise assembly of the ball can be achieved. The movable sealing structure of this embodiment can solve the technical problem that fine deviations are likely to occur during installation and multiple fine-tuning is required.

[0056] The movable sealing ring 200 includes an annular main body 210. A rotating hole 211 is arranged in the middle of the annular main body 210. The annular sealing surface 201 is arranged on the periphery of the annular main body 210; the rotating hole 211 is a through hole. The movable sealing ring 200 is installed on the valve ball 300 through the rotating hole 211, and when adjustment is needed, the movable sealing ring 200 rotates through the position of the rotating hole 211.

[0057] The valve ball 300 is provided with: a first plane 301 formed at one end of the valve ball 1 for sealing; a first stepped column 302 formed on the first plane 301 and perpendicular to the first plane 301; the first stepped column 302 is rotatably sleeved in the rotation hole 211, and the height of the first stepped column 302 ≤ the thickness of the movable sealing ring 200; a gland 303 detachably and fixedly installed on the valve ball 300 for fixing the movable sealing ring 200 sleeved on the first stepped column 302.

[0058] When the valve ball is in the closed position, the first plane 301 faces the flow channel directly, and the axis of the first stepped column 302 coincides with the axis of the flow channel.

[0059] On the first plane 301 opposite to the movable sealing ring 200, a sealing ring installation groove is provided, and a sealing ring is installed inside the sealing ring installation groove. After the movable sealing ring is installed, it helps with sealing.

[0060] On the top surface of the first stepped column 302, a second plane 304 is provided, and a second stepped column 305 is formed on the second plane 304. After the gland 303 is sleeved on the second stepped column 305, it is fixedly installed on the second plane 304 through a bolt 306.

[0061] One end of the gland 303 away from the valve ball 300 is provided with a bolt groove. After the bolt fixes the gland 303 on the second plane 304, the head of the bolt is immersed inside the bolt groove. Such a design can reduce the resistance during the flow of the medium and can also prevent damage to the bolt caused by the erosion of the medium.

[0062] In this embodiment, the sphere is a C-shaped sphere. As a variation, the sphere can also be a sphere with other structures. Embodiment 2

[0063] This embodiment provides a ball valve, as Figure 1 shown, including a valve body 600, a valve ball 300 installed inside the valve body 600 through a valve stem 500, a valve cover 400 installed on the valve body 600, and a valve seat 100 installed inside the valve cover 400; further including a movable sealing structure installed on the valve seat 100 and the valve ball 300, and the movable sealing structure is the movable sealing structure described in Embodiment 1.

[0064] The ball valve of this embodiment, due to adopting the above-mentioned movable sealing structure, naturally has all the advantages brought by adopting the above-mentioned valve ball structure.

[0065] The valve ball sealing surface 201 of the movable sealing ring 200 extends a certain distance around the valve ball 300. The valve ball 300 does not contact the valve seat 100. When wear occurs during long-term use and good sealing cannot be achieved, the movable sealing ring 200 can be replaced, thereby reducing the equipment replacement cost.

[0066] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. The obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. An assembly method for a movable sealing structure, characterized in that, Comprising: A valve seat (100), adapted to be movably mounted on a valve cover (400), having a valve seat sealing surface (101), and the valve seat sealing surface (101) is an eccentric sealing surface; A movable sealing ring (200), adapted to be movably and rotatably mounted on a valve ball (300), having a valve ball sealing surface (201), and the valve ball sealing surface (201) is an eccentric sealing surface capable of cooperating with the valve seat sealing surface (101) for sealing; After the valve seat sealing surface (101) and the valve ball sealing surface (201) are closely attached, sealing is achieved; The movable sealing ring (200) has a fixed state and a rotatable state; when in the fixed state, the movable sealing ring (200) and the valve ball (300) are fixed as a whole; when in the rotatable state, under the action of an external force, the movable sealing ring (200) can rotate relative to the valve ball (300), thereby changing the relative position between the valve ball sealing surface (201) and the valve seat sealing surface (101) to achieve alignment of the sealing surfaces; When assembling the valve ball (300), when the valve seat sealing surface (101) and the valve ball sealing surface (201) are not tightly attached due to inaccurate alignment, loosen the movable sealing ring (200), and by rotating the movable sealing ring (200), quickly adjust the valve seat sealing surface (101) and the valve ball sealing surface (201) to achieve precise alignment, and then re-fix the movable sealing ring (200) after adjustment.

2. The assembly method of the movable seal structure according to claim 1, characterized in that, The valve seat (100) includes a cylindrical main body portion (110), an annular portion (120) provided at one end of the cylindrical main body portion (110), and a sealing portion (130) located at the connection position between the cylindrical main body portion (110) and the annular portion (120), and the valve seat sealing surface (101) is provided at a position on the side of the sealing portion (130) facing the valve ball (300); a recess is formed at the position of the valve cover (400) for mounting the valve seat (100), and the outer wall of the valve seat (100) is attached to the inner wall of the recess.

3. The assembling method of the movable seal structure according to claim 2, characterized in that: The movable sealing structure further includes a valve seat fixing structure, and the valve seat fixing structure includes an annular baffle (140), having a through hole, adapted to be fixed on the valve cover (400) by bolts, and a limiting cavity (141) is formed between a part of the annular baffle (140) and the valve cover (400); An annular protrusion (121) is provided on the outer periphery of the annular portion (120), and the annular protrusion (121) extends into the limiting cavity (141) and is limited by the limiting cavity (141).

4. The assembly method of the movable sealing structure according to claim 3, characterized in that: On the side of the cylindrical main body portion (110) facing the valve cover (400), a first gap (111) and a second gap (112) are formed. The width of the second gap (112) is greater than that of the first gap (111). A valve seat sealing ring (150) is installed inside the first gap (111), and a valve seat bush (160) is installed inside the second gap (112). One end of the valve seat bush (160) fits and inserts into the first gap (111) and squeezes the valve seat sealing ring (150) in the direction of the valve cover (400). A valve seat spring (170) is installed at the other end of the valve seat bush (160). There is a moving gap (180) between the valve seat bush (160) and the side wall of the second gap (112) close to the first gap (111).

5. The assembling method of the movable seal structure according to claim 4, characterized in that: It further includes an annular groove (190) provided on the inner wall of the valve cover (400) outside the valve seat bush (160). A graphite gasket (191) is provided inside the annular groove (190). The part of the graphite gasket (191) extending out of the annular groove (190) is in close contact with the outer wall of the cylindrical main body portion (110).

6. The assembly method of the movable seal structure according to claim 1, characterized in that: The movable sealing ring (200) includes an annular main body (210). A rotating hole (211) is provided in the middle of the annular main body (210). The valve ball sealing surface (201) is provided on the periphery of the annular main body (210); the rotating hole (211) is a through hole.

7. The assembling method of the movable sealing structure according to claim 6, characterized in that: The following are provided on the valve ball (300): A first plane (301) formed at one end of the valve ball (300) for sealing; A first stepped column (302) formed on the first plane (301) and perpendicular to the first plane (301); the first stepped column (302) is adapted to be rotatably sleeved in the rotating hole (211), and the height of the first stepped column (302) ≤ the thickness of the movable sealing ring (200); A gland (303) detachably and fixedly installed on the valve ball (300) for fixing the movable sealing ring (200) sleeved on the first stepped column (302).

8. The assembling method of the movable sealing structure according to claim 7, characterized in that: A second plane (304) is provided on the top surface of the first stepped column (302). A second stepped column (305) is formed on the second plane (304). After the gland (303) is sleeved on the second stepped column (305), it is fixedly installed on the second plane (304) through a bolt (306).

9. A ball valve assembly method, including a valve body (600), a valve ball (300) installed inside the valve body (600) through a valve stem (500), a valve cover (400) installed on the valve body (600), and a valve seat (100) installed inside the valve cover (400); It is characterized in that: It further includes a movable sealing structure installed on the valve seat (100) and the valve ball (300). The movable sealing structure is assembled by using the assembly method of the movable sealing structure described in any one of claims 1-8.

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