An ultra-low temperature LNG top-mounted hard-seal floating ball valve

Abstract

The present invention relates to the field of valve technology, and discloses an ultra-low temperature LNG top-mounted hard-sealed floating ball valve, comprising a valve body, a valve stem and a valve ball arranged inside the valve body, a mounting seat being arranged on the top of the valve body, the valve stem penetrating the mounting seat, and an adjusting seat being fixedly installed on the bottom end of the valve stem, a mounting cavity being arranged on the inner side of the valve body, the valve ball being movably arranged in the mounting cavity, a sliding groove being arranged on the top end of the valve ball, and the adjusting seat being slidably arranged in the sliding groove; the present invention arranges an adjusting component so that when the valve is opened, the adjusting block can be driven to move by the adjusting component, so that the adjusting block pushes the valve ball to move in a direction away from the valve seat, so that the valve ball is separated from the valve seat, so that the valve ball will not contact the valve seat when it starts to rotate, so that the friction force of the valve ball when it rotates is reduced, thereby making the opening of the valve more labor-saving, and avoiding the relative friction between the valve ball and the valve seat, thereby reducing the wear of the valve seat and the valve ball, and significantly improving the service life of the valve ball and the valve seat.

Description

Technical Field

[0001] The invention relates to the technical field of valves, in particular to an ultra-low temperature LNG top-mounted hard-sealed floating ball valve. Background Art

[0002] Ultra-low temperature LNG, or liquefied natural gas, is a form of gaseous natural gas cooled to liquid at extremely low temperatures (about -162°C). It is colorless, odorless, non-toxic and non-corrosive, and its volume is about 1 / 625 of the same amount of gaseous natural gas, making it easy to store and transport. As one of the cleanest fossil energy sources on earth, LNG causes very little air pollution after combustion and releases a lot of heat, so it is widely used in industries, civil fuels and chemical raw materials. Floating ball valve is a valve device widely used in industrial automation control systems, and can be used on ultra-low temperature LNG transportation pipelines. It achieves sealing through the fit between the valve seat seal and the ball core. When the valve stem is driven to rotate, the valve stem drives the ball core to rotate to achieve the opening and closing action of the ball valve.

[0003] Chinese patent CN104879520B discloses a pipeline control valve, in particular a floating ball valve, including a valve body, a valve stem, a ball, and a valve seat, wherein the valve seat is provided with a V-shaped groove and an angled structure, wherein the cross section of the V-shaped groove is V-shaped, the opening end of the V-shaped groove is located on the outer circumference side of the valve seat and contacts the valve body, and the angled structure is located on the end face of the valve seat away from the ball, and is an inwardly concave section. Through the design of a new valve seat structure, a valve stem guide structure, and a valve stem sealing structure, the problem of leakage between the ball and the valve seat and the valve stem of the floating ball valve in actual work is solved, the sealing between the ball and the valve seat and the valve stem of the floating ball valve is improved, the risk of internal and external leakage of the floating ball valve is avoided, and the safety and reliability of the ball valve are guaranteed.

[0004] As shown in the above patent, floating ball valves usually rely on highly close contact between the valve ball and the valve seat to achieve sealing. Its working mechanism involves utilizing the hydraulic force generated by the fluid passing through the valve, which pushes the valve ball close to the valve seat, thereby enhancing the sealing effect. However, while this design improves the sealing performance, it also introduces some problems: First, due to the large pressure exerted by the valve ball on the valve seat, when the valve is opened, the high friction between the two will significantly increase the operating torque, making it difficult for the valve ball to rotate; second, continuous high-pressure contact may also accelerate the wear of the valve seat material and affect the service life of the valve.

[0005] Therefore, it is necessary to provide an ultra-low temperature LNG top-mounted hard-seal floating ball valve to solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide an ultra-low temperature LNG top-mounted hard-sealed floating ball valve, in which the valve ball does not contact the valve seat when it starts to rotate, so that the friction force when the valve ball rotates is reduced, thereby making the valve opening more labor-saving, and avoiding the relative friction between the valve ball and the valve seat, reducing the wear of the valve seat and the valve ball.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: an ultra-low temperature LNG top-mounted hard-sealed floating ball valve, comprising a valve body, a valve stem and a valve ball arranged inside the valve body, a mounting seat being arranged on the top of the valve body, the valve stem passing through the mounting seat, and an adjusting seat being fixedly installed on the bottom end of the valve stem, a mounting cavity being arranged on the inner side of the valve body, the valve ball being movably arranged in the mounting cavity, a sliding groove being arranged on the top end of the valve ball, the adjusting seat being slidably arranged in the sliding groove, a valve seat being arranged on one side of the inner cavity of the valve body, an adjusting block being slidably arranged inside the adjusting seat, the end of the adjusting block away from the valve seat extending out of the adjusting seat, and the adjusting block being arranged in the sliding groove, and an adjusting component for driving the adjusting block to move is arranged on the valve stem.

[0008] The present invention is further configured as follows: an adjusting rod is fixedly provided on the top of the valve stem, and a first handle is fixedly mounted on the adjusting rod.

[0009] The present invention is further configured as follows: the adjusting assembly includes an adjusting shaft and a cam, the adjusting shaft is rotatably installed inside the valve stem, and a cam is fixedly installed on the bottom end of the adjusting shaft, one side of the cam is in contact with the side wall of the adjusting block, the top of the adjusting shaft passes through the adjusting rod, and a second handle is fixedly installed on the top of the adjusting shaft.

[0010] The present invention is further configured as follows: an L-shaped rod is fixedly mounted on one side of the top end of the mounting seat, and an elastic locking component is disposed on the top end of the L-shaped rod for locking the second handle after the adjusting shaft is rotated 90°.

[0011] The present invention is further configured as follows: the elastic locking assembly includes an installation box and a one-way card block, the installation box is fixedly installed on the end of the L-shaped rod, the one-way card block is slidably matched with the installation box, the bottom end of the one-way card block extends out of the installation box, an inclined surface is provided at the bottom of the one-way card block, a first spring is provided in the installation box, and the one-way card block is elastically connected to the top inner wall of the installation box through the first spring.

[0012] The present invention is further configured as follows: a driving block is slidably installed in the middle of the L-shaped rod, the driving block is made of iron material, a traction rope is fixedly connected to the top of the one-way clamping block, a guide ring is fixedly installed on the top of the L-shaped rod, the traction rope passes through the guide ring and extends into the interior of the L-shaped rod and then extends out and is fixedly connected to the driving block, and a magnetic block is embedded and installed on one side wall of the first handle at a position corresponding to the driving block.

[0013] The present invention is further configured as follows: a second spring is fixedly connected to the inner side of the L-shaped rod, and the height of the second spring is the same as the height of the second handle.

[0014] The present invention is further configured as follows: the valve body comprises an upper valve shell and a lower valve shell, and the upper valve shell is embedded and installed on the top end of the lower valve shell.

[0015] The present invention is further configured as follows: connecting seats are fixedly installed on both sides of the upper valve shell and the lower valve shell, and the two connecting seats on the same side are abutted against each other and fixedly connected by connecting bolts.

[0016] The present invention is further configured as follows: both ends of the lower valve shell are connected with connection ports, and one side of the inner cavity of the upper valve shell and the lower valve shell is jointly provided with an installation groove for installing the valve seat.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. The present invention sets an adjusting component so that when the valve is opened, the adjusting component can drive the adjusting block to move, so that the adjusting block pushes the valve ball to move in a direction away from the valve seat, so that the valve ball is separated from the valve seat. Therefore, the valve ball will not contact the valve seat when it starts to rotate, so that the friction force when the valve ball rotates is reduced, so that the opening of the valve is more labor-saving, and the relative friction between the valve ball and the valve seat is avoided, thereby reducing the wear of the valve seat and the valve ball, and significantly improving the service life of the valve ball and the valve seat. Through the top-mounted design, the upper valve shell is embedded and installed on the top of the lower valve shell, so that the upper valve shell can be disassembled to maintain and replace the valve seat, valve ball and other parts in the valve body. When disassembling the valve, there is no need to release the connection between the connecting port and the pipeline, which improves the convenience of disassembly;

[0019] 2. The present invention arranges an elastic locking assembly, a driving block and a traction rope so that when the valve is closed, the driving block pulls the one-way clamping block upward through the traction rope, thereby releasing the lock on the second handle, allowing the second handle to rotate in the opposite direction under the elastic action of the second spring, and then rotates together with the rotation of the first handle to reset the second handle. When the valve is closed, the second handle can automatically reset following the rotation of the first handle without other operations, thereby improving the convenience of closing the valve and avoiding safety hazards caused by the complexity of closing the valve in an emergency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0021] Figure 2 It is a cross-sectional structural schematic diagram of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the upper valve housing and the lower valve housing of the present invention;

[0023] Figure 4 It is a structural schematic diagram of the valve ball of the present invention;

[0024] Figure 5 It is a structural schematic diagram of the valve stem and the regulating assembly of the present invention;

[0025] Figure 6 It is a schematic diagram of the structure of the regulating component of the present invention;

[0026] Figure 7 It is a schematic structural diagram of an L-shaped rod and an elastic locking assembly of the present invention;

[0027] Figure 8 It is a schematic structural diagram of the elastic locking assembly, traction rope and driving block of the present invention.

[0028] In the figure: 1. upper valve shell; 2. lower valve shell; 201. mounting groove; 3. connecting port; 4. mounting seat; 5. valve ball; 501. slide groove; 6. valve seat; 7. valve stem; 8. adjusting seat; 9. adjusting rod; 10. first handle; 11. connecting seat; 12. connecting bolt; 13. adjusting shaft; 14. adjusting block; 15. cam; 16. second handle; 17. L-shaped rod; 18. mounting box; 19. traction rope; 20. driving block; 21. guide ring; 22. second spring; 23. magnetic block; 24. one-way clamp block; 25. first spring. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] See also Figures 1 to 8In the embodiment of the present invention, an ultra-low temperature LNG top-mounted hard-sealed floating ball valve comprises a valve body, a valve stem 7 and a valve ball 5 arranged inside the valve body, the valve body comprises an upper valve shell 1 and a lower valve shell 2, the upper valve shell 1 is embedded and installed on the top of the lower valve shell 2, a sealing gasket is provided at the connection between the upper valve shell 1 and the lower valve shell 2 for sealing, both ends of the lower valve shell 2 are connected and provided with a connecting port 3, one side of the inner cavity of the upper valve shell 1 and the lower valve shell 2 is jointly provided with an installation groove 201 for installing a valve seat 6, a mounting seat 4 is provided on the top of the valve body, the valve stem 7 passes through the mounting seat 4, and the valve An adjusting seat 8 is fixedly installed at the bottom end of the rod 7, a mounting cavity is provided on the inner side of the valve body, the valve ball 5 is movably arranged in the mounting cavity, a slide groove 501 is provided on the top of the valve ball 5, the adjusting seat 8 is slidably arranged in the slide groove 501, the sliding direction of the adjusting seat 8 is perpendicular to the axial direction of the valve hole in the valve ball 5, and the valve ball 5 can be driven to rotate by the rotation of the adjusting seat 8. A valve seat 6 is provided on one side of the inner cavity of the valve body, the valve seat 6 is an annular structure, and the contact surface chamfer of the valve seat 6 and the valve ball 5 is an arc structure, so that the fitting area of ​​the valve seat 6 and the valve ball 5 is increased, and the valve seat 6 adopts The adjusting seat 8 is made of copper material to avoid the rubber material from shrinking and deforming easily in a low temperature environment. The adjusting seat 8 is provided with an adjusting block 14 for sliding inside. The end of the adjusting block 14 away from the valve seat 6 extends out of the adjusting seat 8, and the adjusting block 14 is arranged in the slide groove 501. The valve stem 7 is provided with an adjusting component for driving the adjusting block 14 to move. In this scheme, the adjusting component is arranged so that when the valve is opened, the adjusting block 14 can be driven to move by the adjusting component, so that the adjusting block 14 pushes the valve ball 5 to move in a direction away from the valve seat 6, so that the valve ball 5 is separated from the valve seat 6, so that the valve ball 5 When it starts to rotate, it will not contact the valve seat 6, so that the friction force of the valve ball 5 when rotating is reduced, making it easier to open the valve and avoiding the relative friction between the valve ball 5 and the valve seat 6, thereby reducing the wear of the valve seat 6 and the valve ball 5, and significantly improving the service life of the valve ball 5 and the valve seat 6. Through the top-mounted design, the upper valve shell 1 is embedded and installed on the top of the lower valve shell 2, so that the upper valve shell 1 can be disassembled to maintain and replace the valve seat 6, valve ball 5 and other parts in the valve body. When disassembling the valve, there is no need to release the connection between the connecting port 3 and the pipeline, which improves the convenience of disassembly.

[0031] In this embodiment, preferably, an adjusting rod 9 is fixedly provided on the top of the valve stem 7, and a first handle 10 is fixedly installed on the adjusting rod 9. The adjusting rod 9 can be moved by the first handle 10 to rotate the valve stem 7. When the valve stem 7 rotates, the valve ball 5 is driven to rotate through the adjusting seat 8, thereby controlling the opening and closing of the valve.

[0032] In this embodiment, preferably, the adjusting assembly includes an adjusting shaft 13 and a cam 15, the top cross-section of the cam 15 is an elliptical structure, the adjusting shaft 13 is rotatably installed inside the valve stem 7, and the cam 15 is fixedly installed at the bottom end of the adjusting shaft 13, one side of the cam 15 is in contact with the side wall of the adjusting block 14, the top of the adjusting shaft 13 passes through the adjusting rod 9, and a second handle 16 is fixedly installed on the top of the adjusting shaft 13; the adjusting shaft 13 can be rotated by the second handle 16, thereby driving the cam 15 to rotate, and when the cam 15 rotates, it can drive the adjusting block 14 to move, thereby pushing the valve ball 5 to move, so that the valve ball 5 is separated from the valve seat 6.

[0033] In this embodiment, preferably, an L-shaped rod 17 is fixedly installed on one side of the top of the mounting seat 4, and the top of the L-shaped rod 17 is provided with an elastic locking component for locking the second handle 16 after the adjusting shaft 13 rotates 90°; the elastic locking component includes a mounting box 18 and a one-way clamping block 24, the mounting box 18 is fixedly installed at the end of the L-shaped rod 17, the one-way clamping block 24 is slidably matched with the mounting box 18, the bottom end of the one-way clamping block 24 extends out of the mounting box 18, and the bottom of the one-way clamping block 24 is provided with an inclined surface, and a first spring 25 is provided in the mounting box 18, and the one-way clamping block 24 is elastically connected to the top inner wall of the mounting box 18 through the first spring 25; when the second handle 16 drives the adjusting shaft 13 to rotate 90°, after the second handle 16 passes through the inclined surface at the bottom of the one-way clamping block 24, the one-way clamping block 24 locks the second handle 16, thereby locking the adjusting shaft 13, so that when the hydraulic pressure acts on the valve ball 5, the adjusting block 14 will not move under the action of the hydraulic pressure.

[0034] In this embodiment, preferably, a driving block 20 is slidably installed in the middle of the L-shaped rod 17, and the driving block 20 is made of iron material. The top of the one-way block 24 is fixedly connected with a traction rope 19, and the top of the L-shaped rod 17 is fixedly installed with a guide ring 21. The traction rope 19 passes through the guide ring 21 and extends into the interior of the L-shaped rod 17, and then extends out and is fixedly connected to the driving block 20. A magnetic block 23 is embedded and installed on one side wall of the first handle 10 at a position corresponding to the driving block 20; a second spring 22 is fixedly connected to the inner side of the L-shaped rod 17, and the height of the second spring 22 is the same as that of the second handle 16; when the second handle 16 is rotated until it is locked by the one-way block 24, the second handle 16 contacts and compresses the second spring 22, and when the first handle 10 is rotated to After opening the valve, the first handle 10 rotates until the magnet 23 contacts the drive block 20, and the magnet 23 and the drive block 20 are magnetically attracted. When the valve needs to be closed, the first handle 10 is controlled to rotate in the opposite direction. At this time, the magnet 23 pulls the drive block 20 to move through the magnetic attraction force, so that the drive block 20 pulls the one-way clamping block 24 upward through the traction rope 19, thereby releasing the lock on the second handle 16, so that the second handle 16 rotates in the opposite direction under the elastic action of the second spring 22, and then rotates together with the rotation of the first handle 10 to reset the second handle 16. Through the arrangement of the above structure, when closing the valve, the second handle 16 can automatically reset following the rotation of the first handle 10, without the need for other operations, thereby improving the convenience of closing the valve and avoiding safety hazards caused by the complexity of closing the valve in an emergency.

[0035] In the present embodiment, preferably, connecting seats 11 are fixedly installed on both sides of the upper valve shell 1 and the lower valve shell 2, and the two connecting seats 11 on the same side are fitted together and fixedly connected by connecting bolts 12; the upper valve shell 1 and the lower valve shell 2 can be connected together by the connecting bolts 12 and the connecting seats 11, so that the upper valve shell 1 can be disassembled to maintain and replace the valve seat 6, valve ball 5 and other parts in the valve body. The top-mounted valve design makes it unnecessary to release the connection between the connecting port 3 and the pipeline when disassembling the valve, thereby improving the convenience of disassembly.

[0036] Working principle: Through the top-mounted design, the upper valve shell 1 is embedded and installed on the top of the lower valve shell 2, so that the upper valve shell 1 can be disassembled to maintain and replace the valve seat 6, valve ball 5 and other parts in the valve body. When disassembling the valve, there is no need to disconnect the connection port 3 from the pipeline, which improves the convenience of disassembly. The embedded installation method increases the contact area between the upper valve shell 1 and the lower valve shell 2, ensuring the sealing of the connection. By using a copper valve seat 6, the shrinkage of the valve seat 6 in a low temperature environment can be reduced, and the valve seat 6 can be prevented from being corroded by LNG gas, thereby increasing the service life of the valve seat 6.

[0037] When opening the valve, the second handle 16 is first used to drive the adjusting shaft 13 to rotate 90°. When the adjusting shaft 13 rotates, the cam 15 at its bottom end is driven to rotate, so that the cam 15 pushes the adjusting block 14 to move in the direction away from the valve seat 6, and then pushes the valve ball 5 to move in the opposite direction away from the valve seat 6, so that the valve ball 5 is separated from the valve seat 6. After the second handle 16 passes through the inclined surface at the bottom of the one-way block 24, the one-way block 24 locks the second handle 16, thereby locking the adjusting shaft 13, and then the first handle 16 is used to open the valve. The hand 10 moves the adjusting rod 9 to rotate, so that the valve stem 7 rotates. When the valve stem 7 rotates, the valve ball 5 is driven to rotate through the adjusting seat 8, so that the area of ​​the connection between the valve hole on the valve ball 5 and the connecting port 3 gradually increases, so that the valve is opened. When the valve stem 7 rotates, since the adjusting shaft 13 remains stationary, the cam 15 also remains stationary, and the adjusting block 14 rotates with the valve stem 7, the relative position of the adjusting block 14 and the cam 15 is gradually reset to the initial state, thereby preventing the valve ball 5 from deviating and causing the valve ball 5 to be difficult to fully rotate to open the valve;

[0038] When closing the valve, the first handle 10 is controlled to rotate in the opposite direction. At this time, the magnetic block 23 pulls the driving block 20 to move through the magnetic attraction force, so that the driving block 20 pulls the one-way clamping block 24 upward through the traction rope 19, thereby releasing the lock on the second handle 16, so that the second handle 16 rotates in the opposite direction under the elastic action of the second spring 22, and then rotates together with the rotation of the first handle 10 to reset the second handle 16. By adjusting the setting of the component, when opening the valve, the valve ball 5 can be separated from the valve seat 6 first, so that the valve ball 5 will not contact the valve seat 6 when it starts to rotate, so that the friction force of the valve ball 5 when it rotates is reduced, so that the opening of the valve is more labor-saving, and the relative friction between the valve ball 5 and the valve seat 6 is avoided, thereby reducing the wear of the valve seat 6 and the valve ball 5, and significantly improving the service life of the valve ball 5 and the valve seat 6.

[0039] The above description is only a preferred embodiment of the present invention, so all equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. An ultra-low temperature LNG top-mounted hard-seal floating ball valve, comprising a valve body, a valve stem (7) and a valve ball (5) arranged inside the valve body, characterized in that: A mounting seat (4) is arranged on the top of the valve body, the valve stem (7) passes through the mounting seat (4), and an adjusting seat (8) is fixedly installed on the bottom end of the valve stem (7); a mounting cavity is arranged on the inner side of the valve body, the valve ball (5) is movably arranged in the mounting cavity, a slide groove (501) is arranged on the top end of the valve ball (5), the adjusting seat (8) is slidably arranged in the slide groove (501), a valve seat (6) is arranged on one side of the inner cavity of the valve body, an adjusting block (14) is slidably arranged inside the adjusting seat (8), one end of the adjusting block (14) away from the valve seat (6) extends out of the adjusting seat (8), and the adjusting block (14) is arranged in the slide groove (501), and an adjusting component for driving the adjusting block (14) to move is arranged on the valve stem (7); An adjusting rod (9) is fixedly provided on the top of the valve stem (7), and a first handle (10) is fixedly mounted on the adjusting rod (9); The adjustment assembly comprises an adjustment shaft (13) and a cam (15); the adjustment shaft (13) is rotatably mounted inside the valve stem (7); the cam (15) is fixedly mounted on the bottom end of the adjustment shaft (13); one side of the cam (15) is in contact with the side wall of the adjustment block (14); the top of the adjustment shaft (13) passes through the adjustment rod (9); and a second handle (16) is fixedly mounted on the top of the adjustment shaft (13).

2. The ultra-low temperature LNG top-loading hard-sealed floating ball valve according to claim 1 is characterized by: An L-shaped rod (17) is fixedly mounted on one side of the top end of the mounting seat (4), and an elastic locking component is provided at the top end of the L-shaped rod (17) for locking the second handle (16) after the adjustment shaft (13) is rotated 90°.

3. The ultra-low temperature LNG top-loading hard-seal floating ball valve according to claim 2 is characterized by: The elastic locking assembly comprises a mounting box (18) and a one-way clamping block (24); the mounting box (18) is fixedly mounted on the end of the L-shaped rod (17); the one-way clamping block (24) is slidably matched with the mounting box (18); the bottom end of the one-way clamping block (24) extends out of the mounting box (18); an inclined surface is provided at the bottom of the one-way clamping block (24); a first spring (25) is provided in the mounting box (18); and the one-way clamping block (24) is elastically connected to the top inner wall of the mounting box (18) via the first spring (25).

4. The ultra-low temperature LNG top-loading hard-seal floating ball valve according to claim 3 is characterized by: A driving block (20) is slidably mounted in the middle of the L-shaped rod (17), the driving block (20) being made of iron material, a traction rope (19) being fixedly connected to the top of the one-way clamping block (24), a guide ring (21) being fixedly mounted on the top of the L-shaped rod (17), the traction rope (19) passing through the guide ring (21) and extending into the interior of the L-shaped rod (17) and then extending out and being fixedly connected to the driving block (20), and a magnetic block (23) is embedded and mounted on a side wall of the first handle (10) at a position corresponding to the driving block (20).

5. The ultra-low temperature LNG top-loading hard-seal floating ball valve according to claim 4 is characterized in that: A second spring (22) is fixedly connected to the inner side of the L-shaped rod (17), and the height of the second spring (22) is the same as the height of the second handle (16).

6. The ultra-low temperature LNG top entry hard seal floating ball valve according to claim 1 is characterized by: The valve body comprises an upper valve shell (1) and a lower valve shell (2), wherein the upper valve shell (1) is embedded and installed on the top end of the lower valve shell (2).

7. The ultra-low temperature LNG top-loading hard-seal floating ball valve according to claim 6 is characterized by: Connecting seats (11) are fixedly mounted on both sides of the upper valve housing (1) and the lower valve housing (2); the two connecting seats (11) on the same side are attached to each other and fixedly connected by connecting bolts (12).

8. The ultra-low temperature LNG top entry hard seal floating ball valve according to claim 6 is characterized by: Both ends of the lower valve shell (2) are connected to each other and provided with connection ports (3), and one side of the inner cavity of the upper valve shell (1) and the lower valve shell (2) is provided with a mounting groove (201) for mounting a valve seat (6).

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