Online pressure mechanical seal maintenance half ball valve

Abstract

The utility model provides a kind of on-line pressure mechanical seal maintenance half ball valve, it is related to valve field.Valve body and the valve plate rotationally arranged in valve body interior, valve body includes: the access hole of being arranged in top;Oppositely set in the inlet and outlet of valve body both sides, outlet is equipped with the working sealing pair of sealing cooperation with valve plate;Access hole is equipped with the maintenance sealing pair of sealing cooperation with valve plate, maintenance sealing pair includes: the inner wall of being slidably arranged in its along access hole axial direction with auxiliary valve seat, auxiliary valve seat is equipped with the sealing element of sealing cooperation with valve plate in valve plate one end close to;Elastic member is arranged along access hole axial direction, for elastically supporting auxiliary valve seat;Valve cover is detachably connected to valve body, and it is arranged in auxiliary valve seat outside;Valve cover is equipped with pressure gauge and pressure relief structure with valve body interior connection, and valve cover is equipped with adjusting assembly, adjusting assembly is used to control the axial movement of auxiliary valve seat. It can be carried out inside half ball valve component maintenance under the normal operation pressure state of pipeline, without removing from pipeline.

Description

Technical Field

[0001] This utility model relates to the field of valves, and more specifically, to a ball valve for online maintenance of a mechanical seal under pressure. Background Technology

[0002] The top-mounted eccentric ball valve utilizes an eccentric valve body, eccentric ball, and valve seat. As the valve stem rotates, they automatically center themselves along a common trajectory, tightening further during closure to achieve a perfect seal. Over long-term use, if the valve seat seal wears or is damaged, the pressure depth of the valve body seat can be adjusted. Under this pressure, the valve seat automatically pushes against the ball, thus providing excellent automatic compensation.

[0003] However, existing technologies for top-mounted eccentric ball valves only allow for the installation and disassembly of internal components from the top of the valve without removing it from the pipeline. They cannot enable online maintenance during normal operation, thus failing to achieve the goal of quickly disassembling and repairing the sealing surfaces while the pipeline is functioning normally. This results in relatively high maintenance costs, tight maintenance schedules, and reduced production capacity due to the interruption of media supply during maintenance. Utility Model Content

[0004] The purpose of this utility model is to provide an online pressurized mechanical seal maintenance hemispherical valve, which can perform internal component maintenance of the hemispherical valve under pressurized conditions during normal pipeline operation without disassembly from the pipeline; it reduces maintenance costs, shortens maintenance operation time, reduces labor intensity, and avoids the problem of reduced production capacity caused by the cessation of medium supply in traditional valves without affecting the normal transportation of fluid media.

[0005] The embodiments of this utility model are implemented as follows:

[0006] This application provides an online pressure-controlled mechanical seal maintenance hemispherical valve, including a valve body and a valve plate rotatably disposed inside the valve body, the valve body comprising:

[0007] Access panel located at the top;

[0008] The inlet and outlet are respectively arranged on both sides of the valve body, and the outlet is provided with a working sealing pair that seals with the valve plate;

[0009] The inspection port is provided with an inspection sealing pair that seals with the valve plate, the inspection sealing pair comprising:

[0010] A secondary valve seat is slidably disposed on the inner wall of the inspection port along the axial direction, and a sealing element that seals with the valve plate is provided at the end of the secondary valve seat near the valve plate.

[0011] An elastic element is provided along the axial direction of the inspection port to elastically support the secondary valve seat;

[0012] A valve cover is detachably connected to the valve body and disposed outside the auxiliary valve seat; the valve cover is provided with a pressure gauge and a pressure relief structure connected to the inside of the valve body, and an adjustment component is provided through the valve cover, the adjustment component being used to control the axial movement of the auxiliary valve seat.

[0013] Furthermore, based on the aforementioned scheme, an annular groove is provided on the inner wall of the inspection port;

[0014] The secondary valve seat has an annular step at one end near the valve cover; the annular step slides in conjunction with the annular groove.

[0015] The elastic element is disposed in the annular groove, and its two ends respectively abut against the opposite surfaces of the annular groove and the annular step.

[0016] Furthermore, based on the aforementioned scheme, the elastic element includes a plurality of compression springs evenly distributed along the circumference of the annular groove.

[0017] Furthermore, based on the aforementioned scheme, the secondary valve seat has an inclined surface at one end near the valve plate that is adapted to the sealing surface of the valve plate cutout; the sealing element is embedded in the inclined surface.

[0018] Furthermore, based on the aforementioned scheme, the maintenance sealing pair also includes a secondary valve seat pressure ring, which is disposed between the outer end face of the secondary valve seat and the valve cover; the secondary valve seat pressure ring is detachably connected to the valve body, and the valve cover is detachably connected to the secondary valve seat pressure ring; the adjusting component passes through the valve cover and the secondary valve seat pressure ring in sequence.

[0019] Furthermore, based on the aforementioned scheme, the adjusting component includes an adjusting bolt, the adjusting bolt being threaded through the secondary valve seat pressure ring; the valve cover has a through hole, the through hole being coaxially opposite to the adjusting bolt.

[0020] Furthermore, based on the aforementioned scheme, the adjustment component includes an internal hexagonal screw plug, which is threadedly sealed to the outer end of the through hole.

[0021] Furthermore, based on the aforementioned scheme, the maintenance sealing pair also includes a pressure plate assembly disposed inside the valve cover, the pressure plate assembly being threadedly connected to the valve cover via a pressure rod; a limiting structure is provided on the inner wall of the secondary valve seat near the valve cover, the limiting structure being used to form an axial limiting fit with the outer edge of the pressure plate assembly.

[0022] Furthermore, based on the aforementioned scheme, the pressure plate assembly includes a plurality of inspection plates extending radially along the periphery of the pressure rod, the plurality of inspection plates being connected to the pressure rod; a plurality of limiting structures are provided, each corresponding to one of the plurality of inspection plates.

[0023] Furthermore, based on the aforementioned scheme, sealing rings are respectively provided between the outer wall of the secondary valve seat and the valve body, and between the outer wall of the secondary valve seat pressure ring and the valve body.

[0024] Compared with the prior art, the embodiments of this utility model have at least the following advantages or beneficial effects:

[0025] This application provides a maintenance sealing pair at the inspection port on the top of the valve body. The maintenance sealing pair includes a secondary valve seat axially sliding on the inner wall of the inspection port. A sealing element is provided at the end of the secondary valve seat near the valve plate to seal against the valve plate. This allows the secondary valve seat to seal against the valve plate when it moves downwards, forming a maintenance sealing structure. This enables maintenance work on the valve plate while the valve is running. Furthermore, by providing an elastic element at the inspection port to elastically support the secondary valve seat, the sealing element is prevented from failing due to excessive adjustment depth of the secondary valve seat during maintenance. To improve the sealing effect of the valve during maintenance; by installing a pressure gauge and a pressure relief structure on the valve cover, it is possible to monitor the presence of pressure at the maintenance port in real time, and to relieve pressure at the maintenance port, so that the pressure at the maintenance port can be emptied during maintenance, facilitating maintenance; by installing an adjustment component through the valve cover, it is used to control the axial movement of the secondary valve seat, driving the secondary valve seat to move down or up, realizing the sealing and separation of the secondary valve seat and the valve plate. When the secondary valve seat moves down and abuts against the valve plate to seal, the pressure is released through the pressure relief structure, and the valve cover can be opened to expose the valve plate for maintenance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the external structure of the hemispherical valve for online pressure-controlled mechanical seal maintenance according to an embodiment of this utility model;

[0028] Figure 2 This is a side cross-sectional view of a hemispherical valve used for online repair of a mechanical seal under pressure, according to an embodiment of this utility model.

[0029] Figure 3 This is a sectional view of the main cross-section of the hemispherical valve used for online repair of mechanical seals according to an embodiment of this utility model;

[0030] Figure 4 This utility model Figure 3 Enlarged schematic diagram of the structure at point A in the middle;

[0031] Figure 5This is a schematic diagram of the sealing structure between the valve plate and the maintenance sealing pair in the maintenance state according to an embodiment of this utility model;

[0032] Figure 6 This is a partial structural schematic diagram of the inspection port in an embodiment of this utility model.

[0033] Icons: 1-Valve body, 11-Inspection port, 111-Annular groove, 12-Inlet, 13-Outlet, 14-Sealing ring, 15-Upper valve stem, 16-Lower valve stem, 2-Valve plate, 21-Valve plate sealing ring, 3-Working sealing pair, 4-Inspection sealing pair, 41-Secondary valve seat, 411-Annular step, 412-Limiting structure, 42-Seal, 43-Elastic element, 44-Valve cover, 45-Adjusting assembly, 451-Adjusting bolt, 452-Hex socket screw plug, 46-Secondary valve seat pressure ring, 47-Inspection plate, 48-Pressure rod, 5-Pressure gauge, 6-Pressure relief structure. Detailed Implementation

[0034] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0035] Please refer to Figures 1-6 The image shows a schematic diagram of the overall structure of a hemispherical valve undergoing online pressurized mechanical seal maintenance.

[0036] This embodiment provides an online pressurized mechanical seal maintenance hemispherical valve, including a valve body 1 and a valve plate 2 rotatably disposed inside the valve body 1. The valve body 1 includes:

[0037] Inspection port 11 is located at the top;

[0038] The inlet 12 and outlet 13 are respectively arranged on both sides of the valve body 1. The outlet 13 is provided with a working sealing pair 3 that seals with the valve plate 2.

[0039] The access port 11 is provided with an access sealing pair 4 that seals with the valve plate 2. The access sealing pair 4 includes:

[0040] The auxiliary valve seat 41 is slidably disposed on the inner wall of the inspection port 11 along the axial direction. A sealing element 42 that seals with the valve plate 2 is provided at the end of the auxiliary valve seat 41 near the valve plate 2.

[0041] The elastic element 43 is arranged axially along the inspection port 11 and is used to elastically support the auxiliary valve seat 41.

[0042] The valve cover 44 is detachably connected to the valve body 1 and is located outside the auxiliary valve seat 41. The valve cover 44 is provided with a pressure gauge 5 and a pressure relief structure 6 connected to the inside of the valve body 1, and the valve cover 44 is provided with an adjustment component 45, which is used to control the axial movement of the auxiliary valve seat 41.

[0043] The following will further describe an online pressure-operated mechanical seal maintenance hemispherical valve according to this exemplary embodiment.

[0044] In some implementations, refer to Figure 1 and Figure 2 The valve plate 2 is rotatably mounted on the valve body 1 via an upper valve stem 15 and a lower valve stem 16. The upper valve stem 15 is connected to an external drive device (not shown), which drives the valve plate 2 to rotate inside the valve body 1. The outlet 13 of the valve body 1 is provided with a working sealing pair 3 that seals with the valve plate 2. This working sealing pair 3 seals with the valve plate sealing ring 21 on the outside of the valve plate 2, ensuring that the outlet 13 is sealed when the valve is normally closed. After repeated opening and closing of the valve, the valve plate sealing ring 21 may wear, leading to sealing failure. In cases of slight failure, the sealing effect can be compensated to some extent by adjusting the downward pressure depth of the working sealing pair 3, thereby extending the service life of the valve plate sealing ring 21. When this adjustment method fails to achieve a sealing effect, the valve plate sealing ring 21 needs to be inspected and replaced. Therefore, a maintenance sealing pair 4 that seals with the valve plate 2 is provided at the inspection port 11.

[0045] Reference Figure 3 and Figure 4 The aforementioned maintenance sealing assembly 4 includes a secondary valve seat 41, an elastic element 43, and a valve cover 44. The secondary valve seat 41 is axially slidably disposed on the inner wall of the maintenance port 11. A sealing element 42 that seals with the valve plate 2 is disposed at the end of the secondary valve seat 41 near the valve plate 2, allowing the secondary valve seat 41 to move axially until the sealing element 42 seals with the valve plate 2, thereby enabling maintenance and replacement of the valve plate sealing ring 21 while the valve is in a normally open state. The elastic element 43 is axially disposed along the maintenance port 11 and is used to elastically support the secondary valve seat 41, thereby limiting the movement of the secondary valve seat 41 during maintenance to prevent the sealing element 42 from failing due to excessive adjustment depth, and also enabling the secondary valve seat 41 to move and reset. The valve cover 44 is detachably connected to the valve body 1 and is located outside the auxiliary valve seat 41. The valve cover 44 is equipped with a pressure gauge 5 and a pressure relief structure 6 connected to the inside of the valve body 1. The pressure gauge 5 monitors the pressure at the inspection port 11 in real time. When maintenance is required, the pressure is released through the pressure relief structure 6 to empty the pressure at the inspection port 11. The pressure relief structure 6 can be a pressure venting pipeline with a valve, which allows maintenance work to be carried out in a pressure-free state in the bypass channel without affecting the normal operation of the main pipeline, reducing maintenance difficulty and improving safety. In addition, the valve cover 44 is equipped with an adjustment component 45, which is used to control the axial movement of the auxiliary valve seat 41. When the auxiliary valve seat 41 is moved downward until the sealing element 42 seals with the valve plate 2, a pressure relief operation can be performed. After the pressure is released, the valve cover 44 can be removed from the valve body 1 to expose the valve plate 2, thereby enabling maintenance of the valve plate sealing ring 21.

[0046] In a preferred embodiment, the inner wall of the inspection port 11 is provided with an annular groove 111; the secondary valve seat 41 near the valve cover 44 is provided with an annular step 411; the annular step 411 is slidably engaged with the annular groove 111; the elastic element 43 is disposed in the annular groove 111, and its two ends respectively abut against the opposite surfaces of the annular groove 111 and the annular step 411. By providing the annular groove 111 and the annular step 411, the axial movement of the secondary valve seat 41 is limited on the one hand, and the elastic element 43 is conveniently disposed on the other hand.

[0047] Furthermore, the elastic element 43 includes multiple compression springs evenly distributed circumferentially along the annular groove 111. When the secondary valve seat 41 is pressed down, the compression springs provide buffer support for the secondary valve seat 41, preventing it from moving down too quickly or too far, which could cause the seal 42 to fail due to compression. After maintenance, the compression springs can drive the secondary valve seat 41 to move up and reset. The aforementioned seal 42 is the piston seal ring 14.

[0048] In a preferred embodiment, the auxiliary valve seat 41 has an inclined surface at one end near the valve plate 2 that matches the sealing surface of the valve plate 2's cut; the sealing element 42 is embedded in the inclined surface. When the auxiliary valve seat 41 moves downwards, the knife-shaped cut sealing surface of the valve plate 2 fits against the piston sealing ring 14, forming a maintenance sealing structure. This is the maintenance working state, such as... Figure 5 .

[0049] In a preferred embodiment, the aforementioned maintenance sealing assembly 4 further includes a secondary valve seat pressure ring 46, which is disposed between the outer end face of the secondary valve seat 41 and the valve cover 44. The secondary valve seat pressure ring 46 is detachably connected to the valve body 1, and the valve cover 44 is detachably connected to the secondary valve seat pressure ring 46. The adjusting assembly 45 passes through the valve cover 44 and the secondary valve seat pressure ring 46 in sequence. By providing the secondary valve seat pressure ring 46, the secondary valve seat 41 can be limited and fixed, preventing the secondary valve seat 41 from detaching from the valve body 1 during maintenance, thereby causing sealing failure.

[0050] In a preferred embodiment, the aforementioned adjusting assembly 45 includes an adjusting bolt 451, the adjusting bolt 451 being threaded through the secondary valve seat pressure ring 46; the valve cover 44 has a through hole, the through hole being coaxially opposite to the adjusting bolt 451. When moving the secondary valve seat 41, a special bolt tightening tool is used to screw the adjusting bolt 451 downwards, causing it to push the secondary valve seat 41 downwards, so that the piston sealing ring 14 at the bottom of the secondary valve seat 41 abuts and seals against the valve plate sealing ring 21.

[0051] Furthermore, the aforementioned through hole is configured as a stepped hole, with the diameter of the upper part of the through hole being smaller than the outer diameter of the end of the adjusting bolt 451 that contacts the tool, thereby limiting the adjusting bolt 451 to the lower part of the through hole.

[0052] In a preferred embodiment, the adjustment component 45 includes an internal hexagonal screw plug 452, which is threadedly sealed to the outer end of the through hole, serving to limit and protect the adjustment bolt 451, and also to seal the through hole.

[0053] It should be noted that multiple sets of the aforementioned adjusting components 45 are provided, and are evenly and symmetrically distributed around the valve cover 44. During adjustment, the symmetrical adjusting bolts 451 are adjusted first to ensure stable sealing of the secondary valve seat 41.

[0054] As a preferred implementation method, refer to Figure 6 The aforementioned maintenance sealing assembly 4 also includes a pressure plate assembly disposed inside the valve cover 44. The pressure plate assembly is threadedly connected to the valve cover 44 via a pressure rod 48. A limiting structure 412 is provided on the inner wall of the end of the secondary valve seat 41 near the valve cover 44. The limiting structure 412 is used to form an axial limiting fit with the outer edge of the pressure plate assembly. By setting the pressure plate assembly, during maintenance, the maintenance pressure plate is first moved downward to the maximum position by rotating the pressure rod 48 downward. The limiting fit simultaneously drives the secondary valve seat 41 downward to abut against the valve plate 2. Then, the secondary valve seat 41 is fixed by rotating the adjusting bolt 451 downward to ensure that it achieves a sealing effect. After purging the maintenance port 11, maintenance can begin. In this way, the secondary valve seat 41 can be moved downward to a suitable position quickly and stably, avoiding the need to adjust multiple adjusting bolts 451 sequentially, which would cause uneven downward movement of the secondary valve seat 41 and lead to an unbalanced seal. It should be noted that when not under maintenance, the pressure plate assembly should be rotated to the highest limit (the pressure plate assembly contacts the valve cover 44) to prevent friction between the pressure plate assembly and the valve plate 2 when the valve is normally open.

[0055] Furthermore, the aforementioned pressure plate assembly includes multiple inspection plates 47 extending radially along the periphery of the pressure rod 48, and the multiple inspection plates 47 are connected to the pressure rod 48; multiple limiting structures 412 are provided, each corresponding to one of the multiple inspection plates 47. In this way, the auxiliary valve seat 41 can be stably driven to move downward.

[0056] The aforementioned limiting structure 412 is a U-shaped block installed on the inner wall of the secondary valve seat 41, with the opening facing upwards, forming a limiting groove for the edge of the inspection plate 47 to be inserted and fitted.

[0057] As a preferred embodiment, in order to improve the sealing effect of the valve body 1, sealing rings 14 are respectively provided between the outer wall of the auxiliary valve seat 41 and the valve body 1, and between the outer wall of the auxiliary valve seat pressure ring 46 and the valve body 1.

[0058] Working principle of the embodiments in this application:

[0059] In the shut-off working state, the sealing surfaces of the valve body sealing seat and the valve plate sealing ring 21 of the working sealing pair 3 are in contact to form a shut-off sealing structure. When the valve plate sealing ring 21 needs to be inspected / replaced, the external drive device is started. Under the drive of the external drive device, the valve plate 2 is rotated to the side of the valve cover 44. With the valve open, the inspection plate 47 is pressed down to the maximum position. The internal hexagonal plug 452 on the valve cover 44 is removed. Then, by symmetrically adjusting the adjusting bolt 451 on the auxiliary valve seat pressure ring 46, a special bolt tightening tool is used to screw the adjusting bolt 451 in the auxiliary valve seat pressure ring 46 to move the auxiliary valve seat 41 downward. At this time, the knife-shaped cut sealing surface of the valve plate 2 is in contact with the piston sealing ring 14 of the auxiliary valve seat 41 to form an inspection sealing structure. This is the inspection working state. After the secondary valve seat 41 is pressed into place, the medium inside the valve cover 44 is emptied through the pressure relief structure 6 on the valve cover 44. After the medium is emptied, the fastening bolts of the valve cover 44 are opened from the outside of the valve body 1, and the valve cover 44 is removed, exposing the entire inspection port 11. At this time, the valve plate sealing ring 21 is exposed inside the inspection port 11, allowing maintenance personnel to perform online maintenance operations while the pipeline is operating normally. Using disassembly tools, the pressure plate assembly, the ball crown, and the valve plate sealing ring 21 are disassembled in sequence, and the damaged valve plate sealing ring 21 is removed. The mounting end face of the valve plate sealing ring 21 is cleaned, a new valve plate sealing ring 21 is replaced, the ball crown is installed on the upper part of the valve plate sealing ring 21 and locked; the valve cover 44 is installed, and the pressure relief component is closed.

[0060] After overhauling / replacing the valve plate sealing ring 21, the inspection plate 47 and valve cover 44 should be installed sequentially. During installation, ensure the inspection plate 47 is placed within the limiting groove of the auxiliary valve seat 41, keeping the auxiliary valve seat 41 pressed down. Then, unscrew the adjusting bolts 451 on the auxiliary valve seat pressure ring 46 to move the auxiliary valve seat 41 upwards. Tighten the internal hexagonal plug 452 on the valve cover 44. At this point, the knife-shaped notch sealing surface of the valve plate 2 disengages from the piston sealing ring 14 in the online maintenance channel, indicating the maintenance is complete. Finally, rotate the inspection plate 47 to its highest limit. The overhaul / replacement of the valve plate sealing ring 21 is now complete. Reverse the operation of the external drive device. Under the drive of the external drive device, the valve plate 2 rotates in the opposite direction around the valve stem to the valve body 1 sealing seat. At this point, the valve plate sealing ring 21 fits against the sealing surface of the valve body 1 sealing seat, forming a working sealing structure. Finally, check for leaks using pressure gauge 5. If there are no leaks, restart the external drive device to open valve plate 2 to the required opening degree. If there are leaks, repeat the above steps until the test is passed.

[0061] Compared with traditional ball valves, this invention solves the problem that ball valves on the market cannot perform online maintenance while the pipeline is operating normally. It also addresses the difficulties faced by other valves, such as gate valves, butterfly valves, ball valves, and globe valves, in performing maintenance while the pipeline is operating normally. Therefore, this application reduces maintenance costs, shortens maintenance time, reduces labor intensity, and avoids the problem of reduced production capacity caused by the cessation of medium supply in traditional valves, without affecting the normal transport of fluid media.

[0062] Furthermore, unless otherwise explicitly specified or limited, the terms "installation" and "connection" in this application embodiment should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. The terms "upper," "lower," "left," "right," "inner," "outer," and "side," etc., are merely for reference to the direction in the accompanying drawings or the usual placement of the product during use. They are only for clearly describing this application and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limitations on this application. The terms "first," "second," etc., are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance; "multiple" refers to at least two. In this application embodiment, the limitations on relative positional relationships such as parallel, perpendicular, and aligned are all relative to the current technological level and are not absolutely strict limitations. Slight deviations are allowed; approximations of parallel, perpendicular, and aligned are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 degrees and 10 degrees.

[0063] The above are only some embodiments and implementation methods of this application. The protection scope of this application is not limited thereto. In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. Any combination of features in different embodiments is also within the protection scope of this application. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. An online pressurized mechanical seal maintenance hemispherical valve, comprising a valve body and a valve plate rotatably disposed inside the valve body, the valve body comprising: Access panel located at the top; The inlet and outlet are respectively arranged on both sides of the valve body, and the outlet is provided with a working sealing pair that seals with the valve plate; The feature is that the inspection port is provided with an inspection sealing pair that seals with the valve plate, the inspection sealing pair comprising: A secondary valve seat is slidably disposed on the inner wall of the inspection port along the axial direction, and a sealing element that seals with the valve plate is provided at the end of the secondary valve seat near the valve plate. An elastic element is provided along the axial direction of the inspection port to elastically support the secondary valve seat; A valve cover is detachably connected to the valve body and disposed outside the auxiliary valve seat; the valve cover is provided with a pressure gauge and a pressure relief structure connected to the inside of the valve body, and an adjustment component is provided through the valve cover, the adjustment component being used to control the axial movement of the auxiliary valve seat.

2. The online, pressure-seal mechanical seal service semi-sphere valve of claim 1, wherein, The inner wall of the inspection port is provided with an annular groove; The secondary valve seat has an annular step at one end near the valve cover; the annular step slides in conjunction with the annular groove. The elastic element is disposed in the annular groove, and its two ends respectively abut against the opposite surfaces of the annular groove and the annular step.

3. The online, pressure-seal mechanical seal service semi-sphere valve of claim 2, wherein, The elastic element includes multiple compression springs evenly distributed along the circumference of the annular groove.

4. The online, pressure-seal mechanical seal service semi-sphere valve of claim 1, wherein, The secondary valve seat has an inclined surface at one end near the valve plate that is adapted to the sealing surface of the valve plate cutout; the sealing element is embedded in the inclined surface.

5. The online, pressure-seal mechanical seal service semi-sphere valve of claim 1, wherein, The maintenance sealing pair also includes a secondary valve seat pressure ring, which is disposed between the outer end face of the secondary valve seat and the valve cover; the secondary valve seat pressure ring is detachably connected to the valve body, and the valve cover is detachably connected to the secondary valve seat pressure ring; the adjusting component passes through the valve cover and the secondary valve seat pressure ring in sequence.

6. The online, pressure-seal mechanical seal service semi-sphere valve of claim 5, wherein, The adjusting assembly includes an adjusting bolt, the adjusting bolt being threaded through the secondary valve seat pressure ring; the valve cover has a through hole, the through hole being coaxial with and opposite to the adjusting bolt.

7. The online, pressure-seal mechanical seal service half-ball valve of claim 6, wherein, The adjusting component includes an internal hexagonal screw plug, which is threadedly sealed to the outer end of the through hole.

8. The online, pressure-seal mechanical seal service semi-sphere valve of claim 5, wherein, The maintenance sealing pair also includes a pressure plate assembly disposed inside the valve cover, the pressure plate assembly being threadedly connected to the valve cover via a pressure rod; a limiting structure is provided on the inner wall of the secondary valve seat near the valve cover, the limiting structure being used to form an axial limiting fit with the outer edge of the pressure plate assembly.

9. The online, pressure-seal mechanical seal service semi-sphere valve of claim 8, wherein, The pressure plate assembly includes a plurality of inspection plates extending radially along the periphery of the pressure rod, and the plurality of inspection plates are connected to the pressure rod; a plurality of limiting structures are provided, each corresponding to one of the plurality of inspection plates.

10. The online pressurized mechanical seal maintenance hemispherical valve according to any one of claims 5-9, characterized in that, A sealing ring is provided between the outer wall of the secondary valve seat and the valve body, and between the outer wall of the secondary valve seat pressure ring and the valve body.

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