Stop valve and valve control method

Abstract

The application discloses a stop valve and a valve control method. The stop valve comprises a valve pipe fitting, which is installed on a medium pipeline and has an inner diameter larger than that of the medium pipeline, and the bottom of the valve pipe fitting is provided with symmetrically distributed first fan-shaped through holes; a valve block, which is a stepped cylindrical structure and has an outer diameter matched with the inner diameter of the valve pipe fitting, and the valve block is provided with second fan-shaped through holes extending along the axial direction and having the same size as the first fan-shaped through holes; a stepped surface of the stepped cylindrical structure and the bottom of the valve pipe fitting form an annular cavity; and an annular tubular air bag is arranged in the annular cavity. In the inflation process, the valve block converts the axial force acting on the valve block into a rotary driving force through a concave track on the inner wall surface of the valve pipe fitting. The application can realize a straight-through type and maintain a closed state by relying on the medium pressure in the stop valve, and will not affect the current working state due to the failure of a pneumatic device.

Description

Technical Field

[0001] This invention relates to the field of pipeline transportation control, and in particular to a shut-off valve and a valve control method. Background Technology

[0002] With the continuous development of modern industry, gate valves are used in petrochemical, power engineering, metallurgical, urban construction, chemical plants and other industries. Due to the diversity of pipeline control and the complexity of process conditions, the demand for control valves is constantly increasing. In fluid pipelines, gate valves are important switches for connecting or disconnecting the pipeline medium. Traditional gate valves control the flow of media by manually or electrically operating valve components (rotating a handwheel) to move the valve stem axially. However, this operation can lead to several problems: 1. Electrically controlled gate valves often require a dedicated electric actuator, resulting in large space requirements and high costs. 2. The electric actuator is typically vertically positioned, causing excessive pressure on the motor's main bearing. Mechanical imbalance during operation can easily damage it. 3. If a motor malfunctions, the gate valve it controls will also fail to operate, leading to low overall system reliability. 4. Traditional gate valves have a tortuous media path, high energy consumption, and significant fluid resistance losses. 5. When closed, the gate valve relies on the valve stem pressure to tightly seal the valve disc against the valve seat, preventing media flow. A mechanical failure in the electric actuator can compromise the closure. 6. The sealing surfaces of traditional gate valves are constantly in contact with the flowing media in the pipeline, making them susceptible to corrosion and wear, resulting in poor sealing and potential leakage after closure.

[0003] In addition to manual and electric shut-off valves, existing technologies also include pneumatically driven shut-off valves. For example, Chinese patent CN206017745U discloses a pneumatic shut-off valve, including a handwheel, a manual lever, a pneumatic shaft, a carrier, a valve cover, and a valve body. A manual lever is mounted below the handwheel and connected to it. A coupling is mounted below the carrier and connected to the valve stem. A valve disc is fixedly mounted below the valve cover and connected to the valve body. A locking device is fixedly mounted on the right side of the manual lever. The carrier and valve cover are connected via a rotating rod, and rotating rods are fixedly mounted on both sides of the coupling. In this pneumatic shut-off valve, the handwheel's rotation range is 0 to 90°. When fluid resistance is high, only a maximum rotation of 90° is needed to open and close. However, this type of solution still requires manual operation and has a relatively complex structure and high cost.

[0004] Therefore, there is an urgent need for a shut-off valve and valve control method that avoids the high cost of manual and electric throttle valves, and can achieve a straight-through type that relies on the pressure of the medium inside the shut-off valve to maintain the closed state, so that the current working state will not be affected by the failure of the pneumatic device.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a shut-off valve and valve control method, which can achieve a straight-through type, rely on the pressure of the medium inside the shut-off valve to maintain the closed state, and will not be affected by the failure of the pneumatic device.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a shut-off valve is provided, comprising: a valve fitting mounted on a medium pipeline with an inner diameter larger than that of the medium pipeline, the valve fitting having symmetrically distributed first sector-shaped through holes at its bottom; a valve block having a stepped cylindrical structure with an outer diameter adapted to the inner diameter of the valve fitting, the valve block having a second sector-shaped through hole extending axially and having the same size as the first sector-shaped through hole; a stepped surface of the stepped cylindrical structure forming an annular cavity with the bottom of the valve fitting; and an annular tubular air bladder disposed in the annular cavity, wherein during inflation, the valve block converts the axial force acting on it into a rotational driving force through a concave track on the inner wall of the valve fitting.

[0008] Furthermore, in the above technical solution, the sum of the areas of the two symmetrically distributed first sector-shaped through holes is equal to the cross-sectional area of ​​the medium pipeline; the sum of the areas of the two symmetrically distributed second sector-shaped through holes is also equal to the cross-sectional area of ​​the medium pipeline.

[0009] Furthermore, in the above technical solution, the opening range of both the first sector-shaped through hole and the second sector-shaped through hole is less than half the circumference.

[0010] Furthermore, in the above technical solution, the bottom outer edge of the valve fitting may be provided with an annular wedge-shaped protrusion, the inner diameter of which is adapted to the first step diameter of the stepped cylinder of the valve block; the outer edge surface of the annular wedge-shaped protrusion and the stepped surface of the stepped cylindrical structure form an annular cavity.

[0011] Furthermore, in the above technical solution, a first ball groove can be provided on the second outer edge surface of the stepped cylinder of the valve block. Correspondingly, a wavy concave track is provided on the inner wall surface of the valve fitting, and the first ball rolls in the wavy concave track to form the rotation of the valve block.

[0012] Furthermore, in the above technical solution, the wavy concave track can be provided with four sections along the circumference. Each section can include a first section arranged obliquely and a second section arranged laterally. The first ball moves from the starting position of the first section of this section to the starting position of the first section of the next section, and the valve block completes a 90° rotation, thereby realizing the complete opening or complete closing of the shut-off valve.

[0013] Furthermore, in the above technical solution, a rolling ring can be provided on the side of the stepped surface of the stepped cylindrical structure of the valve block inside the annular cavity, and a second ball groove is provided on the stepped surface. During the rotation of the valve block, the stepped surface and the rolling ring form rolling friction through the second ball.

[0014] Furthermore, in the above technical solution, the side of the rolling ring facing the annular cavity may be provided with an arc surface adapted to the annular tubular airbag.

[0015] Furthermore, in the above technical solution, a sealing layer is provided at the joint between the valve block and the bottom surface of the valve fitting, and the sealing layer can be bonded to the first end face of the stepped cylindrical structure of the valve block.

[0016] Furthermore, in the above technical solution, the annular tubular airbag can be connected to the inflation device through an external air supply line for inflating and deflating the annular tubular airbag.

[0017] According to a second aspect of the present invention, the present invention provides a valve control method for controlling the opening and closing of a medium pipeline using a shut-off valve as described above, comprising the following steps: A. Installing a valve block having a stepped cylindrical structure at the bottom of a valve fitting, such that the first step is inserted into the inner edge of an annular wedge-shaped protrusion, the stepped surface and the outer edge surface of the annular wedge-shaped protrusion forming an annular cavity; B. Inflating the annular tubular air bladder in the annular cavity, so that the valve block is subjected to an axial force away from the bottom of the valve fitting; C. Under the action of the axial force, the first ball on the outer edge surface of the second step of the stepped cylinder rolls along a wavy concave track on the inner wall surface of the valve fitting, so that the axial force is converted into a rotational driving force for the valve block.

[0018] Furthermore, in the above technical solution, the axial force in step C is converted into the rotational driving force of the valve block, which can be specifically described as follows: four sections are arranged along the circumference of the wavy concave track, each section including a first section arranged obliquely and a second section arranged laterally. The first ball moves from the starting position of the first section of this section to the starting position of the first section of the next section, and the valve block completes a 90° rotation, thereby realizing the complete opening or complete closing of the shut-off valve.

[0019] Furthermore, in the above technical solution, the process of the first ball completing one motion cycle may include: the first ball moving obliquely from the starting position of the first segment of this section to the starting position of the second segment, at which time the valve block completes a 90° rotation and the inflation of the annular tubular air bladder ends and is deflated; after deflating, the valve block re-seales and adheres to the bottom of the valve fitting under the action of the medium pressure.

[0020] Furthermore, in the above technical solution, rolling friction can be generated on the stepped surface of the valve block during rotation.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) This invention saves space occupied by the gate valve to the maximum extent through the structural design of valve fittings and valve block; the gate valve is designed as a straight-through type, which consumes less energy and overcomes the tortuous medium channel and high energy consumption of traditional gate valves, reducing the possibility of wear or damage to the valve body and valve disc sealing ring.

[0023] 2) The present invention can effectively drive the valve block to rotate 90° in the circumferential direction by the combination of an annular tubular airbag, a rolling ring and a wave-shaped concave track. The structure is simple and the opening and closing of the shut-off valve is easier to control.

[0024] 3) This invention can use the pressure of the medium inside the shut-off valve to maintain the valve's open and closed state, and will not affect its current working state due to the failure of the pneumatic device.

[0025] 4) The sealing surface of the shut-off valve of the present invention has a short contact time with the medium in the pipe, and only a large area is in contact during the operation. The aging rate of the sealing surface is slowed down, which can prevent the medium from leaking after the sealing ring loses its sealing performance.

[0026] 5) This invention uses a pneumatically driven shut-off valve for switching action, without mechanical, directional, or positional requirements. The pneumatic device can control multiple shut-off valves simultaneously, reducing the space occupied and lowering control costs. By applying the pneumatic shut-off valve of this invention, two or more pneumatic devices can be connected in parallel to control the shut-off valves, improving the reliability of the pipeline system.

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of the shut-off valve installed on the medium pipeline according to Embodiment 1 of the present invention (showing the relative positional relationship between the valve block and the valve fittings).

[0029] Figure 2 This is a schematic diagram of the valve block of the shut-off valve in Embodiment 1 of the present invention.

[0030] Figure 3 This is a top view of the valve block of the shut-off valve in Embodiment 1 of the present invention.

[0031] Figure 4 This is a schematic diagram of the inflation of the annular tubular airbag in Embodiment 1 of the present invention.

[0032] Figure 5This is a schematic diagram of the unfolded inner wall of the valve fitting in Embodiment 1 of the present invention (showing the structure of the wavy concave track and the movement trajectory of the first ball in the track).

[0033] Figure 6 This is a schematic diagram of the structure of the rolling ring in Embodiment 1 of the present invention.

[0034] Explanation of key figure labels:

[0035] 1-Valve fitting, 10-Bottom of valve fitting, 101-Annular wedge-shaped protrusion, 11-Wave-shaped concave track, 2-Valve block, 20-Sealing layer, 21-First step, 22-Second step, 220-Stepped surface, 221-First ball groove, 222-Second ball groove, 23-Second fan-shaped through hole, 3-Media pipeline, 4-Annular tubular airbag, 41-External air supply pipeline, 42-Inflation device, 5-Rolling ring, 51-Second rolling groove, 6-Annular cavity, 7-First ball, 8-Second ball. Detailed Implementation

[0036] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0037] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0038] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0039] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0040] Example 1

[0041] like Figure 1 As shown, the shut-off valve of this embodiment includes a valve fitting 1, a valve block 2, and an annular tubular air bladder 4. The valve fitting 1 is installed on the medium pipeline 3, and the inner diameter of the valve fitting 1 is larger than the inner diameter of the medium pipeline 3. The bottom 10 of the valve fitting 1 has two symmetrically distributed first sector-shaped through holes (the number of these first sector-shaped through holes is two, symmetrically arranged, and both are connected to the medium pipeline, not shown in the figure). The valve block 2 has a stepped cylindrical structure (see reference). Figure 2 Furthermore, the outer diameter of valve block 2 is compatible with the inner diameter of valve fitting 1, and valve block 2 is installed inside valve fitting 1 with a clearance fit. Valve block 2 is provided with a second sector-shaped through hole 23 extending axially and having the same size as the first sector-shaped through hole (see reference). Figure 2 , Figure 3 ). Further as Figure 1 , Figure 2 As shown, the stepped surface 220 of the stepped cylindrical structure and the bottom of the valve fitting 1 form an annular cavity 6. The annular tubular airbag 4 is disposed in the annular cavity 6. During the inflation process of the annular tubular airbag 4, the valve block 2 converts the axial force acting on the valve block into a rotational driving force through the concave track 11 on the inner wall of the valve fitting 1. By rotating the valve block, the first sector-shaped through hole and the second sector-shaped through hole can be selectively fully connected or completely offset, thereby realizing the opening and closing of the shut-off valve in this embodiment.

[0042] Preferably, but not restrictively, the sum of the areas of the two symmetrically distributed first sector-shaped through holes is equal to the cross-sectional area of ​​the medium pipeline 3. The shape and size of the first sector-shaped through hole are exactly the same as those of the second sector-shaped through hole 23. Therefore, the sum of the areas of the two symmetrically distributed second sector-shaped through holes 23 is also equal to the cross-sectional area of ​​the medium pipeline. This design is to ensure that when the shut-off valve is open, the flow rate of the medium at the valve is the same as the flow rate in the medium pipeline, and there is no loss of flow. Furthermore, the opening range of both the first sector-shaped through hole and the second sector-shaped through hole 23 is less than half a circumference, that is, the opening range of each sector-shaped through hole is less than a quarter of a circumference. In this way, when the shut-off valve is in the closed state, the unopened area on the circumference of the valve fitting bottom 10 can effectively block the two second sector-shaped through holes 23 on the valve block 2. At the same time, the unopened area on the end face of the valve block 2 can effectively block the first sector-shaped through hole on the valve fitting bottom 10. When valve block 2 is rotated 90° and is in the open state, the first sector-shaped through hole and the second sector-shaped through hole 23 completely overlap and are in a fully conductive state.

[0043] Further as Figure 1 , 2As shown, the bottom 10 of the valve fitting has an annular wedge-shaped protrusion 101 on its outer edge. The inner diameter of the annular wedge-shaped protrusion 101 is matched with the diameter of the first step 21 of the stepped cylinder of the valve block 2, that is, the first step 21 is inserted into the annular wedge-shaped protrusion 101 with a clearance fit. The outer edge surface of the annular wedge-shaped protrusion 101 (reference) Figure 1 The triangular inclined plane in the sectional view and the stepped surface 220 of the stepped cylindrical structure form an annular cavity 6. An annular tubular airbag 4 (see reference) is disposed within the annular cavity 6. Figure 4 After inflation, valve block 2 can be pushed outward (i.e., towards...). Figure 1 The left-side pressure (as shown in the image) generates an axial force acting on the stepped surface 220 of valve block 2. Further reference... Figure 4 The annular tubular airbag 4 can be connected to the inflation device 42 via an external air supply line 41 for inflating and deflating the annular tubular airbag 4.

[0044] Further as Figure 2 , 3 As shown, the outer edge surface of the second step 22 of the stepped cylinder of valve block 2 is provided with a first ball groove 221. In this embodiment, four first ball grooves 221 are symmetrically arranged along the circumference. Accordingly, further as shown... Figure 5 As shown, the inner wall surface of valve fitting 1 is provided with a wavy concave track 11. Under the action of the aforementioned axial force, the first ball 7 rolls within the wavy concave track 11, thereby causing the valve block 2 to rotate relative to valve fitting 1. Specifically, for ease of understanding, this embodiment unfolds the inner wall surface of valve fitting 1 as shown below. Figure 5 The description further explains that the wavy concave track 11 has four sections along its circumference, each section including a first section 111 arranged obliquely and a second section 112 arranged laterally, with four first balls in... Figure 5 The four positions (i.e., each first ball is spaced a quarter of a circumference apart), the first ball 7 starts from the starting position of the first segment 111 of this section (i.e., a certain section) (i.e., Figure 5 The first ball bearing (position 7, indicated by the solid line) moves to the starting position of the first segment of the next section, and the valve block completes a 90° rotation, thereby achieving the complete opening or closing of the shut-off valve. Further, as... Figure 5 As shown, in this complete motion cycle, firstly, the first ball 7 moves diagonally along the first segment 111 from its starting position (i.e., ... Figure 5 From the direction of the dotted arrow pointing to the upper left of the middle section to the starting position of the second segment 112 (i.e. Figure 5(The position of the first ball 7 is shown by the dashed line). At this point, continuing to inflate and maintain the axial force is no longer able to push the first ball 7 to move further to the left in the figure, proving that the valve block has completed a 90° rotation. At this time, the inflation of the annular tubular air bladder 4 ends and the air is released. After the air is released, the valve block 2 re-seales with the bottom 10 of the valve fitting 1 under the action of the medium pressure. At this time, the first ball 7 moves from the dashed line position to the next solid line position, thus completing a 90° rotation cycle.

[0045] Further as Figure 1 , 6 As shown, a rolling ring 5 is provided inside the annular cavity 6, on one side of the stepped surface 220 near the stepped cylindrical structure of the valve block 2. A second ball groove 222 is provided on the stepped surface 220 (see...). Figure 3 During rotation, the stepped surface 220 of the valve block 2 and the rolling ring 5 experience rolling friction through the second ball bearing 8. The rolling ring 5 is the preferred configuration. While the valve block 2 can still rotate without the rolling ring, it would experience significant friction due to direct sliding friction with the annular tubular airbag 4, hindering rotation and affecting the airbag's lifespan. The rolling ring 5 creates rolling friction during valve block rotation, effectively reducing friction while ensuring the annular tubular airbag 4 remains relatively stationary, avoiding unnecessary friction and pulling. Further... Figure 1 As shown, the side of the rolling ring 5 facing the annular cavity 6 is provided with an arc surface that is adapted to the annular tubular airbag 4, which can form a semi-enclosed state for the airbag, thereby obtaining a uniform axial force and providing the best protection for the airbag.

[0046] Further as Figure 1 As shown, a sealing layer 20 is provided at the joint between the valve block 2 and the bottom surface 10 of the valve fitting. The shape and size of the sealing layer 20 are the same as the shape and size of the end face of the first step 21 of the valve block 2, and it is bonded to the end face of the first step 21 of the stepped cylindrical structure of the valve block 2. When the shut-off valve is closed, the sealing layer 20 can completely seal the medium.

[0047] This embodiment maximizes space savings for the gate valve through its structural design of valve fittings and valve block. The gate valve is designed as a straight-through type, resulting in lower energy consumption and overcoming the problems of tortuous media channels and high energy consumption inherent in traditional gate valves. It also reduces the possibility of wear or damage to the valve body and valve disc sealing rings. Through the cooperation of the annular tubular air bladder, rolling ring, and corrugated concave track, the valve block can be effectively driven to rotate 90° circumferentially. The structure is simple, and the opening and closing of the gate valve is easier to control. This embodiment utilizes the pressure of the medium inside the gate valve to maintain its open and closed state, preventing damage caused by external pressure. The pneumatic device malfunction can affect its current working status; in this embodiment, the sealing surface of the shut-off valve has a short contact time with the medium in the pipe, and only a large area is in contact during the operation, which slows down the aging rate of the sealing surface and prevents the medium from leaking after closure due to the loss of sealing performance of the sealing ring; the shut-off valve is pneumatically driven for opening and closing, without mechanical, directional, or positional requirements, and the pneumatic device can control multiple shut-off valves simultaneously, reducing the space occupied and lowering control costs; by using the pneumatic shut-off valve of this embodiment, two or more pneumatic devices can be connected in parallel to control the shut-off valve, improving the reliability of the pipeline system.

[0048] Example 2

[0049] This embodiment provides a valve control method that uses a shut-off valve as described in Embodiment 1 to control the opening and closing of a medium pipeline, including the following steps:

[0050] Step S101: Install the valve block 2 with a stepped cylindrical structure at the bottom of the valve fitting 1, so that the first step 21 is inserted in the inner edge of the annular wedge protrusion 101, and the stepped surface 220 and the outer edge surface of the annular wedge protrusion 101 form an annular cavity 6.

[0051] Step S102: Inflate the annular tubular airbag 4 in the annular cavity 6 so that the valve block 2 is subjected to an axial force away from the bottom 10 of the valve fitting.

[0052] In step S103, under the action of the axial force in step S102, the first ball 7 on the outer edge of the second step 22 of the stepped cylinder rolls along the wavy concave track 11 on the inner wall of the valve fitting 1, so that the axial force is converted into the rotational driving force of the valve block 2. Specifically, the wavy concave track 11 can be arranged in four sections along the circumference, each section including a first section 111 arranged obliquely and a second section 112 arranged laterally. The first ball 7 moves from the starting position of the first section 111 of the current section to the starting position of the first section 111 of the next section. In this way, the valve block completes a 90° rotation, thereby realizing the complete opening or complete closing of the shut-off valve. Further, the process of the first ball 7 completing one motion cycle includes: 1) The first ball 7 moves from the starting position of the first section 111 of the current section obliquely along the first section to the starting position of the second section 112 (i.e. Figure 5(The position of the ball bearing is indicated by the dotted line). At this point, the valve block 2 completes a 90° rotation, and the inflation of the annular tubular air bladder 4 ends and it deflates; 2) After the annular tubular air bladder 4 deflates, the valve block 2 re-seals against the bottom of the valve fitting under the pressure of the medium. Preferably, but not restrictively, during the rotation of the valve block 2, rolling friction is formed at the stepped surface 220 by the setting of the rolling ring 5.

[0053] This embodiment achieves the same technical effect as Embodiment 1 by using the shut-off valve of Embodiment 1 and following the above steps.

[0054] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A shut-off valve, characterized in that, include: A valve fitting is installed on a medium pipeline and the inner diameter of the valve fitting is larger than the inner diameter of the medium pipeline. The bottom of the valve fitting is provided with symmetrically distributed first sector-shaped through holes. The valve block has a stepped cylindrical structure and its outer diameter is adapted to the inner diameter of the valve fitting. The valve block has a second sector-shaped through hole that extends axially and has the same size as the first sector-shaped through hole. The stepped surface of the stepped cylindrical structure and the bottom of the valve fitting form an annular cavity. An annular tubular airbag is disposed in the annular cavity. During the inflation process, the valve block converts the axial force acting on the valve block into a rotational driving force through the concave track on the inner wall of the valve fitting. By rotating the valve block, the first sector-shaped through hole and the second sector-shaped through hole can be selectively fully connected or completely offset, thereby realizing the opening and closing of the shut-off valve. The valve fitting has an annular wedge-shaped protrusion at its bottom outer edge. The inner diameter of the annular wedge-shaped protrusion is adapted to the first step diameter of the stepped cylinder of the valve block. The outer edge of the annular wedge-shaped protrusion and the stepped surface of the stepped cylindrical structure form the annular cavity. A rolling ring is provided in the annular cavity, near the stepped surface of the stepped cylindrical structure of the valve block. A second ball groove is provided on the stepped surface. During the rotation of the valve block, the stepped surface and the rolling ring form rolling friction through the second ball.

2. The shut-off valve according to claim 1, characterized in that, The sum of the areas of the two symmetrically distributed first sector-shaped through holes is equal to the cross-sectional area of ​​the medium pipe; the sum of the areas of the two symmetrically distributed second sector-shaped through holes is also equal to the cross-sectional area of ​​the medium pipe.

3. The shut-off valve according to claim 2, characterized in that, The opening range of both the first and second sector-shaped through holes is less than half the circumference.

4. The shut-off valve according to claim 1, characterized in that, The valve block has a first ball groove on the second outer edge of the stepped cylinder. Correspondingly, the valve fitting has a wavy concave track on its inner wall. The first ball rolls in the wavy concave track to rotate the valve block.

5. The shut-off valve according to claim 4, characterized in that, The wavy concave track has four sections along its circumference. Each section includes a first section arranged obliquely and a second section arranged laterally. The first ball moves from the starting position of the first section of the current section to the starting position of the first section of the next section. The valve block completes a 90° rotation, thereby realizing the complete opening or complete closing of the shut-off valve.

6. The shut-off valve according to claim 1, characterized in that, The side of the rolling ring facing the annular cavity has an arc surface adapted to the annular tubular airbag.

7. The shut-off valve according to claim 1, characterized in that, A sealing layer is provided at the joint between the valve block and the bottom surface of the valve fitting, and the sealing layer is bonded to the first end face of the stepped cylindrical structure of the valve block.

8. The shut-off valve according to claim 1, characterized in that, The annular tubular airbag is connected to an inflation device via an external air supply line for inflating and deflating the annular tubular airbag.

9. A valve control method, characterized in that, Controlling the opening and closing of a medium pipeline using a shut-off valve as described in any one of claims 1 to 8 includes the following steps: A. Install the valve block with a stepped cylindrical structure at the bottom of the valve fitting, so that the first step is inserted in the inner edge of the annular wedge-shaped protrusion, and the stepped surface and the outer edge of the annular wedge-shaped protrusion form an annular cavity. B. Inflate the annular tubular air bladder inside the annular cavity so that the valve block is subjected to an axial force away from the bottom of the valve fitting; C. Under the action of the axial force, the first ball on the second outer edge of the stepped cylinder rolls along the wavy concave track on the inner wall of the valve fitting, so that the axial force is converted into the rotational driving force of the valve block.

10. The valve control method according to claim 9, characterized in that, The axial force in step C is converted into the rotational driving force of the valve block as follows: The wavy concave track is arranged in four sections along the circumference. Each section includes a first section arranged obliquely and a second section arranged laterally. The first ball moves from the starting position of the first section of the current section to the starting position of the first section of the next section. The valve block completes a 90° rotation, thereby realizing the complete opening or complete closing of the shut-off valve.

11. The valve control method according to claim 10, characterized in that, The process of the first ball completing one motion cycle includes: The first ball moves diagonally from the starting position of the first segment to the starting position of the second segment. At this time, the valve block completes a 90° rotation and the inflation of the annular tubular airbag ends and the air is released. After the air is released, the valve block re-seales and adheres to the bottom of the valve fitting under the pressure of the medium.

12. The valve control method according to claim 9, characterized in that, During rotation, the valve block generates rolling friction on the stepped surface.

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