Bidirectional sealing structure for large-diameter ball valve

Abstract

The invention relates to the technical field of ball valves, and discloses a two-way sealing structure for a large-diameter ball valve, the two-way sealing structure is symmetrically arranged on the water inlet side and the water outlet side of the ball valve, the ball valve comprises a valve body and a ball core arranged in an inner cavity of the valve body, and the two-way sealing structure comprises valve seats movably arranged on the water inlet side and the water outlet side of the ball core; a main sealing seat is arranged on the side, close to the ball core, of the valve seat, a flange is movably connected to the side, away from the ball core, of the valve seat through a spring, a small piston is movably embedded among the flange, the valve seat and the ball core, a valve cavity is formed among the small piston, the flange and the ball core, a gap is formed among the small piston, the valve seat and the flange, and a first channel is formed between the valve seat and the ball core. The flange is provided with a second channel communicated with the valve cavity and the inner cavity of the valve body, and the small piston is provided with a third channel communicated with the valve cavity and the gap. Two-way sealing of the water inlet side and the water outlet side of the ball valve can be achieved, the sealing performance is greatly improved, and the application scene is greatly widened.

Description

Technical Field

[0001] The invention relates to the technical field of ball valves, and more particularly to a bidirectional sealing structure for large-diameter ball valves. Background Art

[0002] In industrial fluid delivery systems, large-diameter ball valves play a key role in cutting off and controlling the flow of media. Their sealing performance is directly related to the operating stability, safety and cost-effectiveness of the entire system.

[0003] Traditional large-diameter ball valve sealing structures mostly adopt a single-side sealing design, which only focuses on the medium blocking in a single direction. If the actual sealing force is too large at the beginning of the design, the sealing life will be reduced. If it is too small, it will easily cause leakage. In addition, the sealing surface is severely worn under multiple switches, which may cause the failure of the seal here and lead to leakage problems in the entire ball valve. Moreover, this design has many limitations when dealing with complex and changeable working conditions. On the one hand, in actual industrial production, the flow direction of the medium is not fixed. Many process flows require frequent switching of the medium flow direction. The one-way sealing structure cannot meet the needs of two-way cutoff, resulting in a significant reduction in the sealing effect under non-design flow conditions, and the medium is prone to leakage, which not only causes material loss, but also may cause safety hazards and environmental pollution problems.

[0004] Therefore, the existing one-way sealing technology of large-diameter ball valves can no longer meet the stringent requirements of today's complex industrial scenarios for ball valve sealing performance, adaptability to working conditions, operation and maintenance cost control, and other aspects. Summary of the invention

[0005] In view of this, the present invention provides a bidirectional sealing structure for a large-diameter ball valve, which can achieve bidirectional sealing on the water inlet side and the water outlet side of the ball valve. The valve seat on the water inlet side and the valve seat on the water outlet side can achieve sealing in both directions in front of and behind the valve seat, greatly improving the sealing performance and application scenarios.

[0006] To achieve the above-mentioned purpose, the present invention provides a bidirectional sealing structure for a large-caliber ball valve, which is symmetrically arranged on the water inlet side and the water outlet side of the ball valve, the ball valve comprises a valve body and a ball core arranged in the inner cavity of the valve body, the ball core is provided with a valve stem rotatably connected to the valve body, the bidirectional sealing structure comprises a valve seat movably arranged on the water inlet side and the water outlet side of the ball core, a main sealing seat is provided on the side of the valve seat close to the ball core, a flange is movably connected to the side of the valve seat away from the ball core through a spring, a small piston is movably embedded between the flange, the valve seat and the ball core, a valve cavity is formed between the small piston, the flange and the ball core, and a gap is formed between the small piston, the valve seat and the flange;

[0007] A first channel is provided between the valve seat and the ball core, a second channel connecting the valve cavity and the inner cavity of the valve body is provided on the flange, and a third channel connecting the valve cavity and the gap is provided on the small piston;

[0008] When the bidirectional sealing structure on the water inlet side and the water outlet side of the ball core is working, the medium filled in the valve cavity is introduced into the gap between the small piston and the flange through the third channel, thereby pushing the small piston to move toward the ball core, so that the small piston pushes the valve seat to move toward the ball core.

[0009] Preferably, a groove for installing a spring is provided at the connection between the flange and the valve seat, and a fourth channel connecting the groove and the inner cavity of the valve body is provided on the valve seat, and the fourth channel is used to introduce the medium in the inner cavity of the valve body into the groove for installing the spring.

[0010] Preferably, an auxiliary sealing seat is further provided on a side of the valve seat close to the ball core, and the auxiliary sealing seat is installed on the valve seat through a pressing block.

[0011] Preferably, a guide block for guiding the movement of the small piston is installed on the flange.

[0012] Preferably, a reducing hole penetrating the inner cavity and the outer cavity of the ball core is provided on the side wall of the ball core, the diameter of the reducing hole gradually decreases from the outer cavity to the inner cavity of the ball core, a pressure relief valve is installed in the reducing hole, the pressure relief valve comprises a small ball, a disc spring and a tightening screw, the small ball movably abuts against the inside of the reducing hole, the tightening screw is screwed to one end of the reducing hole close to the outer cavity of the ball core, a disc spring sealed with the ball line is provided between the small ball and the tightening screw, the compression of the disc spring is adjusted by the depth of the tightening screw being screwed into the ball core thread, so that the small ball generates a pre-tightening force on the reducing hole, thereby controlling the opening and closing of the reducing hole.

[0013] Preferably, a plurality of O-rings are provided on the contact surface between the valve seat and the flange.

[0014] Preferably, a plurality of O-rings are provided on the contact surface between the valve seat and the small piston.

[0015] Preferably, a plurality of O-rings are provided on the contact surface between the flange and the small piston.

[0016] It can be seen from the above technical solutions that, compared with the prior art, the bidirectional sealing structure for a large-caliber ball valve disclosed in the present invention can meet the use requirements under various working conditions. The left and right sides of the valve seat on the water inlet and outlet sides can be sealed, thereby achieving a bidirectional sealing effect. In this way, when the medium flows in any direction, there are 2 to 3 seals, which significantly enhances the sealing reliability of the ball valve. At the same time, the present invention also has the following advantages:

[0017] 1. When the air supply pressure at the inlet of the ball valve is insufficient or fluctuates, resulting in insufficient sealing force of the ball valve, the medium is accumulated in the valve cavity, and the sealing can be achieved by relying on the small piston to isolate the upstream and downstream media to avoid waste caused by the discharge and leakage of the media; and when there is leakage or an accident upstream, resulting in insufficient pressure, an independent sealing chamber is formed in the valve cavity to prevent the loss of downstream media, thereby preventing large-scale leakage of the media, causing dangerous situations such as combustion and explosion, and saving media.

[0018] 2. An auxiliary sealing seat is arranged on the outside of the main sealing seat. While playing a certain sealing role, the auxiliary sealing seat can also block the medium with low cleanliness or high viscosity, preventing impurities in the medium from entering the main sealing seat, playing the role of blocking impurities and auxiliary sealing, protecting the main sealing seat from being scratched by impurities, particles and other redundant objects, and increasing the service life of the sealing surface, thereby increasing the life of the entire valve and effectively improving the reliability of long-lasting sealing;

[0019] 3. The diameter of the small piston surface acting on the valve seat can be adjusted to adjust the sealing force so that the actual sealing force is slightly higher than the required sealing force, thereby achieving sealing without causing excessive specific pressure on the sealing surface, reducing the friction between the valve seat and the ball core, and also reducing the friction torque of the ball valve. The torque of the selected actuator becomes smaller accordingly, energy consumption is reduced, the overall ball valve cost is reduced, and the sealing life is effectively improved;

[0020] 4. The pressure relief valve can be used to release the medium in the valve cavity, so that the pressure of the medium in the valve cavity is within a reasonable range, avoiding the small piston, valve seat, main sealing seat and other components from being in a high-load working state all the time, which will aggravate the aging of components and shorten their service life, thereby ensuring the stability and safety of the ball valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 A vertical cross-sectional view of the ball valve of the present invention in an open state;

[0023] Figure 2 For the present invention Figure 1 A magnified view of part A;

[0024] Figure 3 A vertical cross-sectional view of the ball valve of the present invention in a closed state;

[0025] Figure 4 For the present invention Figure 2 Enlarged view of part B.

[0026] Explanation of the reference numerals in the accompanying drawings: valve body-1; ball core-2; valve stem-3; ball core support plate-4; valve seat-5; flange-6; spring-7; main sealing seat-8; auxiliary sealing seat-9; pressure block-10; small piston-11; valve chamber-12; gap-13; guide block-14; O-ring-15; first channel-501; fourth channel-502; second channel-601; third channel-1101. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of an exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Please see attached Figure 1-4 , which is a bidirectional sealing structure for a large-diameter ball valve disclosed in the present invention.

[0029] like Figure 1 As shown, the ball valve includes a valve body 1 and a ball core 2. The ball core 2 is arranged in the inner cavity of the valve body 1 through a ball core support plate 4. A valve stem 3 rotatably connected to the valve body 1 is provided on the ball core 2. The rotation of the ball core 2 can be driven by rotating the valve stem 3. The bidirectional sealing structure for a large-diameter ball valve provided by the present invention is symmetrically arranged on the water inlet side and the water outlet side of the ball valve, so as to achieve a bidirectional sealing effect of the ball valve. No matter which side the medium flows in from, there are multiple seals, which significantly improves the sealing reliability and can cope with a variety of complex working conditions, especially suitable for working conditions where the medium in the pipeline flows in an undirectional manner after the ball valve is installed.

[0030] like Figure 1-3As shown, the bidirectional sealing structure includes a valve seat 5 movably arranged on the water inlet side and the water outlet side of the ball core 2, the side of the valve seat 5 away from the ball core 2 is movably connected with a flange 6 through a spring 7, and a groove for installing the spring 7 is provided at the connection between the flange 6 and the valve seat 5, a small piston 11 is movably embedded between the flange 6, the valve seat 5 and the ball core 2, a valve cavity 12 is formed between the small piston 11, the flange 6 and the ball core 2, a gap 13 is formed between the small piston 11, the valve seat 5 and the flange 6, a guide block 14 for guiding the movement of the small piston 11 is installed on the flange 6, and a plurality of O-rings 15 are provided on the contact surface between the valve seat 5 and the flange 6, the contact surface between the valve seat 5 and the small piston 11, and the contact surface between the flange 6 and the small piston 11. The provision of the O-rings 15 can enable them to form independent channels respectively to avoid mutual interference.

[0031] It should be noted that a main sealing seat 8 and an auxiliary sealing seat 9 are provided on the side of the valve seat 5 close to the ball core 2. The auxiliary sealing seat 9 is installed on the valve seat 5 by a pressing block 10 and is placed on the outer side of the main sealing seat 8. In addition to being able to play a certain sealing role and effectively improve the reliability of the seal, the auxiliary sealing seat 9 has a blocking effect on media with low cleanliness or high viscosity, preventing impurities in the medium from entering the main sealing seat 8, protecting the main sealing seat 8 from being scratched by impurities, particles and other redundant objects, thereby increasing the service life of the sealing surface and thus increasing the life of the entire valve.

[0032] A first channel 501 is provided between the valve seat 5 and the ball core 2, a second channel 601 connecting the valve cavity 12 and the inner cavity of the valve body 1 is provided on the flange 6, a third channel 1101 connecting the valve cavity 12 and the gap 13 is provided on the small piston 11, and a fourth channel 502 connecting the groove and the inner cavity of the valve body 1 is provided on the valve seat 5. The fourth channel 502 is used to introduce the medium in the inner cavity of the valve body 1 into the groove where the spring 7 is installed, so as to generate a force F 活塞 , so as to avoid the situation where the spring 7 cannot be compressed or extended due to the medium pressure in the groove.

[0033] When the bidirectional sealing structure on the water inlet side and the water outlet side of the ball core 2 is working, the medium filled in the valve cavity 12 is introduced into the gap 13 between the small piston 11 and the flange 6 through the third channel 1101, thereby pushing the small piston 11 to move toward the ball core 2, so that the small piston 11 pushes the valve seat 5 to move toward the ball core 2, and seals the ball core 2. The spring force of the thrust auxiliary spring 7 received by the valve seat 5 jointly provides the sealing force of the ball valve, reduces the working load of the spring 7, and prolongs the sealing life of the ball valve, thereby bringing about the effect of small switching torque and energy saving, and at the same time has the advantages of compact structure, small size, light weight, and low cost. In addition, when the small piston 11 applies thrust to the valve seat 5, the small piston 11 can also abut against the ball core 2 in the end, that is, the small piston 11 closes the first channel 501, and cooperates with the main sealing seat 8 and the auxiliary sealing seat 9 to form a multi-channel sealing structure, further improving the sealing effect.

[0034] When the bidirectional sealing structure of the water outlet primary side of the ball core 2 is working, the medium in the gap 13 flows into the inner cavity of the valve body 1 through the third channel 1101, the valve cavity 12, and the second channel 601 in sequence to discharge the medium accumulated in the gap 13 and the valve cavity 12.

[0035] It should be noted that in the actual design, the outer diameter of the valve seat 5 and the inner and outer diameters of the main sealing seat 8 can be determined in the early stage of the design according to the caliber of the ball valve, and then the change of the design sealing force can be achieved by adjusting the inner and outer diameter dimensions of the small piston 11 to meet the needs of the required sealing force. The design sealing force can be close to and slightly higher than the required sealing force, thereby achieving sealing and effectively controlling the structural dimensions of the ball valve, reducing the friction between the valve seat 5 and the ball core 2, increasing the sealing life, reducing the torque of the drive device, reducing energy consumption, and reducing the overall cost of the ball valve.

[0036] In order to further optimize the above technical solution, Figure 3-4 As shown, a pressure relief valve 16 is provided on the side wall of the ball core 2 : the pressure relief valve 16 comprises a small ball 17 , a disc spring 18 , and a tightening screw 19 . Specifically, a reducing hole penetrating the inner cavity and the outer cavity of the ball core 2 is provided on the side wall of the ball core 2, and the diameter of the reducing hole gradually decreases from the outer cavity to the inner cavity of the ball core 2. The pressure relief valve 16 is installed in the reducing hole, and the small ball 17 is movably abutted against the inside of the reducing hole. The spherical surface of the small ball 17 and the reducing hole on the ball core 2 forms a line seal with the conical surface at the abutment point to form a closing and opening effect on the end of the reducing hole with the smallest diameter. The tightening screw 19 is screwed on the end of the reducing hole close to the outer cavity of the ball core 2, and a disc spring 18 is provided between the small ball 17 and the tightening screw 19 to seal with the small ball 17. The compression of the disc spring 18 is adjusted by the depth of the tightening screw 19 screwed into the thread of the ball core 2, so that the small ball 17 produces a suitable pre-tightening force on the reducing hole, thereby controlling the opening and closing of the reducing hole to achieve sealing.

[0037] When the ball valve is in a closed state and the inner cavity pressure of the ball core 2 is 1.3 times the outer cavity pressure, the medium pressure pushes the small ball 17 to move away from the ball core 2. Since the inner cavity of the ball core 2 is connected with the valve cavity 12 at this time, the medium in the valve cavity 12 is discharged. The valve cavity 12 is connected to the gap 13 through the third channel 1101, so part or all of the medium accumulated in the gap 13 can be discharged at the same time, so that the pressure of the medium in the valve cavity 12 is within a reasonable range, avoiding the small piston 11, the valve seat 5, the main sealing seat 8 and other components from being in a high-load working state all the time, which leads to aggravated aging of parts and shortened service life, thereby ensuring the stability and safety of the ball valve.

[0038] The working principle of the bidirectional sealing structure of the present invention is:

[0039] First, the external force analysis of the ball valve is as follows:

[0040] F 活塞 It is piston force, which is exerted on the valve seat by the fluid medium, and the direction of the external force is toward the ball core;

[0041] F 预紧 It is the preload force, generated by the spring that presses against the valve seat, and the direction of the external force is toward the ball core;

[0042] F 小活塞 It is the force of the small piston acting on the valve seat, which is generated by the medium force in the valve cavity, and the direction of the external force is toward the ball core;

[0043] F 介质 It is the force of the fluid medium in the clearance of the sealing surface, and the direction of the external force is away from the ball core;

[0044] F 必需 It is the minimum force required on the sealing surface when the elastic sealing part of the valve seat and the ball core are sealed, and the direction of the external force is away from the ball core;

[0045] During use, when F 活塞 +F 小活塞 +F 预紧 -F 介质 -F 必需 When >0, sealing is achieved between the valve seat 5 and the ball core 2.

[0046] When the ball valve is closed and the medium flows for the first time, there is a pressure P1 on the upstream side of the valve seat 5. Since the medium has not yet accumulated in the valve cavity 12, there is no pressure. At this time, the medium in the inner cavity of the valve body 1 is in a high-speed flow state. Therefore, the pressure in the inner cavity of the valve body 1 is less than the pressure in the second channel 601. The force F 小活塞 Under the action of the medium, the small piston 11 moves in the direction away from the ball core 2, and then the small piston 11 has no force on the valve seat 5, that is, F 小活塞 =0, the ball valve sealing force is F 活塞 +F预紧 -F 介质 .

[0047] After the ball valve is switched on and off many times, the valve chamber 12 of the ball valve is filled with medium, and the pressure is P2. At this time, the medium pressure in the valve chamber 12 is introduced into the gap 13 between the small piston 11 and the flange 6 through the third channel 1101, pushing the small piston 11 to move to the position of the ball core 2, thereby pushing the valve seat 5 to move in the direction of the ball core 2, that is, F is generated. 小活塞 , at this time the ball valve sealing force is F 活塞 +F 小活塞 +F 预紧 -F 介质 .

[0048] For the outlet valve seat 5, when there is medium in the valve cavity 12, there is no pressure on the outlet side. At this time, the sealing force of the ball valve is F 小活塞 +F 预紧 -F 介质 .

[0049] The bidirectional sealing structure for a large-caliber ball valve provided by the present invention can meet the use requirements under various working conditions. The ball valve can achieve bidirectional sealing. After the pipeline and the ball valve are installed, the system debugging stage is entered. During segmented debugging, the pipe section between the two valves on the pipeline is debugged, and the valve seat 5 at the front valve outlet needs to achieve reverse sealing, while the valve seat 5 at the rear valve inlet needs forward sealing. The bidirectional sealing structure can meet this working condition.

[0050] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bidirectional sealing structure for a large-diameter ball valve, characterized in that: The ball valve is symmetrically arranged on the water inlet side and the water outlet side of the ball valve, the ball valve comprising a valve body (1) and a ball core (2) arranged in the inner cavity of the valve body (1), the ball core (2) being provided with a valve stem (3) rotatably connected to the valve body (1), the bidirectional sealing structure comprising a valve seat (5) movably arranged on the water inlet side and the water outlet side of the ball core (2), the side of the valve seat (5) close to the ball core (2) being provided with a main sealing seat (8), the side of the valve seat (5) away from the ball core (2) being movably connected to a flange (6) via a spring (7), a small piston (11) being movably embedded between the flange (6), the valve seat (5) and the ball core (2), a valve cavity (12) being formed between the small piston (11), the flange (6) and the ball core (2), and a gap (13) being formed between the small piston (11), the valve seat (5) and the flange (6); A first channel (501) is provided between the valve seat (5) and the ball core (2), a second channel (601) communicating with the valve cavity (12) and the inner cavity of the valve body (1) is provided on the flange (6), and a third channel (1101) communicating with the valve cavity (12) and the gap (13) is provided on the small piston (11); When the bidirectional sealing structure on the water inlet side and the water outlet side of the ball core (2) is in operation, the medium filled in the valve chamber (12) is introduced into the gap (13) between the small piston (11) and the flange (6) through the third channel (1101), thereby pushing the small piston (11) to move in the direction of the ball core (2), thereby enabling the small piston (11) to push the valve seat (5) to move in the direction of the ball core (2).

2. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A groove for mounting a spring (7) is provided at the connection between the flange (6) and the valve seat (5), and a fourth channel (502) connecting the groove and the inner cavity of the valve body (1) is provided on the valve seat (5). The fourth channel (502) is used to introduce the medium in the inner cavity of the valve body into the groove for mounting the spring.

3. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: An auxiliary sealing seat (9) is also provided on a side of the valve seat (5) close to the ball core (2); the auxiliary sealing seat (9) is mounted on the valve seat (5) via a pressing block (10).

4. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A guide block (14) for guiding the movement of the small piston (11) is mounted on the flange (6).

5. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A variable diameter through hole penetrating the inner cavity and the outer cavity of the ball core (2) is provided on the side wall of the ball core (2), the diameter of the variable diameter through hole gradually decreases from the outer cavity to the inner cavity of the ball core (2), a pressure relief valve (16) is installed in the variable diameter through hole, the pressure relief valve (16) comprises a small ball (17), a disc spring (18), and a tightening screw (19), the small ball (17) movably abuts against the inside of the variable diameter through hole, the tightening screw (19) is screwed to one end of the variable diameter through hole close to the outer cavity of the ball core (2), a disc spring (18) sealed with the small ball (17) is provided between the small ball (17) and the tightening screw (19), the compression amount of the disc spring (18) is adjusted by the depth of the tightening screw (19) being screwed into the thread of the ball core (2), so that the small ball (17) generates a pre-tightening force on the variable diameter through hole, thereby controlling the opening and closing of the variable diameter through hole.

6. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A plurality of O-rings (15) are provided on the contact surface between the valve seat (5) and the flange (6).

7. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A plurality of O-rings (15) are provided on the contact surface between the valve seat (5) and the small piston (11).

8. The bidirectional sealing structure for a large-diameter ball valve according to claim 1, characterized in that: A plurality of O-rings (15) are provided on the contact surface between the flange (6) and the small piston (11).

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