A bidirectional sealing structure for large-diameter ball valves

Abstract

The present application relates to the technical field of ball valve, and discloses a bidirectional sealing structure for large-diameter ball valve, which is symmetrically arranged on the water inlet side and the water outlet side of the ball valve, and the ball valve comprises a valve body and a ball core arranged in the inner cavity of 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 arranged 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 arranged 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, a gap is formed between the small piston, the valve seat and the flange, a first channel is arranged between the valve seat and the ball core, a second channel is arranged on the flange and communicates the valve cavity and the inner cavity of the valve body, and a third channel is arranged on the small piston and communicates the valve cavity and the gap. The bidirectional sealing of the water inlet side and the water outlet side of the ball valve can be realized, and the sealing performance and the application scene are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ball valves, in particular to a bidirectional sealing structure for a large-diameter ball valve. BACKGROUND

[0002] In an industrial fluid conveying system, a large-diameter ball valve plays a key role in cutting off and controlling the flow of medium, and its sealing performance is directly related to the stability, safety and cost-effectiveness of the entire system.

[0003] Most conventional large-diameter ball valve sealing structures adopt a single-seal design on one side, focusing only on the medium blocking in a single direction. If the actual sealing force is too large in the initial design, it will reduce the sealing life, and if it is too small, it will easily cause leakage. Moreover, the sealing surface is severely worn after repeated opening and closing, which may cause the sealing at this point to fail, leading to leakage of the entire ball valve. Moreover, this design has many limitations when dealing with complex and variable working conditions. On the one hand, in actual industrial production, the flow direction of the medium is not fixed, and many process flows require frequent switching of the medium flow direction. The single-direction sealing structure cannot meet the demand for bidirectional cutting, resulting in a significant reduction in sealing effect under non-design flow conditions, which easily leads to medium leakage, causing material loss, and possibly causing safety hazards and environmental pollution problems.

[0004] Therefore, the existing single-direction sealing technology of large-diameter ball valves has been difficult to meet the stringent requirements of complex industrial scenarios for ball valve sealing performance, working condition adaptability, operation and maintenance cost control, etc. SUMMARY

[0005] Therefore, the present application provides a bidirectional sealing structure for a large-diameter ball valve, which can realize bidirectional sealing of 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 realize sealing in both directions of the front and back of the valve seat, greatly improving the sealing performance and application scenarios.

[0006] To achieve the above-mentioned purpose, the bidirectional sealing structure for a large-diameter ball valve provided by the present application is symmetrically arranged on the water inlet side and the water outlet side of the ball valve. The ball valve includes a valve body and a ball core arranged in the inner cavity of the valve body. A valve stem is arranged on the ball core and rotationally connected to the valve body. The bidirectional sealing structure includes a valve seat 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 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 by a spring. A small piston is movably arranged 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. A gap is formed between the small piston, the valve seat and the flange.

[0007] The first channel is arranged between the valve seat and the ball core, the second channel is arranged on the flange and communicates the valve cavity and the inner cavity of the valve body, and the third channel is arranged on the small piston and communicates the valve cavity and the gap.

[0008] When the bidirectional sealing structure of the water inlet side and the water outlet side of the ball core works, the medium filled in the valve cavity is introduced into the gap between the small piston and the flange through the third channel, so as to push the small piston to move towards the direction of the ball core, and the valve seat is pushed to move towards the direction of the ball core.

[0009] Preferably, a groove for mounting a spring is arranged on the flange at the connection with the valve seat, a fourth channel is arranged on the valve seat and communicates the groove and the inner cavity of the valve body, and the fourth channel is used to introduce the medium in the inner cavity of the valve body into the groove for mounting the spring.

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

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

[0012] Preferably, a variable-diameter through hole is arranged on the side wall of the ball core and penetrates the inner cavity and the outer cavity of the ball core, the diameter of the variable-diameter through hole gradually decreases from the outer cavity to the inner cavity of the ball core, a pressure relief valve is mounted in the variable-diameter through 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 variable-diameter through hole, the tightening screw is screwed at one end of the variable-diameter through hole close to the outer cavity of the ball core, the disc spring is arranged between the small ball and the tightening screw and is in linear sealing with the small ball, and the depth of the tightening screw screwed into the thread of the ball core is used to adjust the compression amount of the disc spring, so that the small ball generates a pre-tightening force on the variable-diameter through hole, thereby controlling the opening and closing of the variable-diameter through hole.

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

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

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

[0016] Compared with the prior art, the bidirectional sealing structure for the large-diameter ball valve provided by the technical solution can meet the use needs under various working conditions, the left and right sides of the valve seat on the water inlet side and the water outlet side can realize sealing, thereby realizing the effect of bidirectional sealing, so that the medium flows in any direction and has 2-3 sealing, which significantly enhances the sealing reliability of the ball valve, and the bidirectional sealing structure has the following advantages:

[0017] 1. When the ball valve inlet gas pressure is insufficient or fluctuation causes the sealing force of the ball valve to be insufficient, the small piston can also achieve sealing due to the medium accumulated in the valve cavity, isolating the upstream and downstream media, avoiding waste caused by medium discharge and leakage; and when the upstream appears leakage or an accident occurs, causing insufficient pressure, an independent sealing chamber is formed in the valve cavity, preventing the loss of downstream medium, thereby preventing large-scale leakage of the medium, causing dangerous conditions such as combustion explosion, and saving the medium.

[0018] 2. The auxiliary sealing seat is arranged outside the main sealing seat, which can block the medium with low cleanliness or high viscosity, prevent impurities in the medium from entering the main sealing seat, and have the effects of blocking impurities and auxiliary sealing, thereby protecting the main sealing seat from being scratched by impurities, particles and other excess substances, improving the service life of the sealing surface, thereby improving the service life of the whole valve and effectively improving the reliability of the durable sealing.

[0019] 3. The diameter size 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, so that sealing can be achieved without causing excessive specific pressure of the sealing surface, thereby reducing the friction force between the valve seat and the ball core, and also reducing the friction torque of the ball valve, the torque of the selected actuator is correspondingly small, the energy consumption is reduced, the overall ball valve cost is reduced, and the sealing life is effectively improved.

[0020] 4. The medium in the valve cavity can be discharged through the pressure relief valve, 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 being in a high load working state all the time, which can accelerate the aging of the components and shorten the service life, thereby ensuring the stability and safety of the ball valve. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor.

[0022] Figure 1 is a vertical sectional view of the open state of the ball valve of the present application;

[0023] Figure 2 is a vertical sectional view of the open state of the ball valve of the present application; Figure 1 is an enlarged view of part A in the present application;

[0024] Figure 3 is a vertical sectional view of the closed state of the ball valve of the present application;

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

[0026] Explanation of reference numerals in the attached 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 cavity - 12; Clearance - 13; Guide block - 14; O-ring - 15; First channel - 501; Fourth channel - 502; Second channel - 601; Third channel - 1101. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of an exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Please see the appendix Figures 1-4 This invention discloses a bidirectional sealing structure for large-diameter ball valves.

[0029] like Figure 1 As shown, the ball valve includes a valve body 1 and a ball core 2. The ball core 2 is located in the inner cavity of the valve body 1 via a ball core support plate 4. The ball core 2 is provided with a valve stem 3 that is rotatably connected to the valve body 1. Rotating the valve stem 3 can drive the rotation of the ball core 2. The bidirectional sealing structure for large-diameter ball valves provided by this invention is symmetrically arranged on the inlet and outlet sides of the ball valve, which can 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. It is especially suitable for working conditions where the medium in the pipeline flows in a non-directional manner after the ball valve is installed.

[0030] like Figures 1-3As shown, the bidirectional sealing structure comprises valve seats 5 movably arranged on the water inlet side and the water outlet side of the ball core 2, a flange 6 movably connected to the side of the valve seat 5 away from the ball core 2 through a spring 7, a groove for installing the spring 7 being arranged at the connection between the flange 6 and the valve seat 5, a small piston 11 movably arranged 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, a gap 13 being 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 being arranged on the flange 6, and a plurality of O-rings 15 being arranged 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 O-rings 15 are arranged to form independent channels respectively, so as to avoid mutual interference.

[0031] It should be noted that the side of the valve seat 5 close to the ball core 2 is provided with a main sealing seat 8 and an auxiliary sealing seat 9, the auxiliary sealing seat 9 is installed on the valve seat 5 through a pressing block 10 and is arranged outside the main sealing seat 8. In addition to the sealing function, the auxiliary sealing seat 9 can effectively improve the reliability of the sealing. More importantly, the auxiliary sealing seat 9 has a blocking effect on the medium with low cleanliness or high viscosity, prevents impurities in the medium from entering the main sealing seat 8, protects the main sealing seat 8 from being scratched by impurities, particles and other excess substances, prolongs the service life of the sealing surface, and thus improves the service life of the valve.

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

[0033] When the bidirectional sealing structure of the ball core 2 on both the inlet and outlet sides is in operation, the medium filling 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 towards the ball core 2. This allows the small piston 11 to push the valve seat 5 towards the ball core 2, sealing the ball core 2. The thrust force on the valve seat 5, combined with the spring force of the auxiliary spring 7, provides the sealing force of the ball valve, reducing the working load of the spring 7 and extending the sealing life of the ball valve. This results in low switching torque and energy saving, while also offering advantages such as compact structure, small size, light weight, and low cost. Furthermore, when the small piston 11 applies a thrust to the valve seat 5, the small piston 11 can also eventually abut against the ball core 2, that is, the small piston 11 closes the first channel 501, working in conjunction with the main sealing seat 8 and the auxiliary sealing seat 9 to form a multi-seal structure, further improving the sealing effect.

[0034] When the bidirectional sealing structure on the primary water outlet side of the ball core 2 is working, the medium in the gap 13 flows sequentially through the third channel 1101, the valve chamber 12, and the second channel 601 into the inner cavity of the valve body 1, so as to discharge the medium accumulated in the gap 13 and the valve chamber 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 based on the ball valve diameter. Then, the design sealing force can be changed by adjusting the inner and outer diameters of the small piston 11 to meet 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. This reduces the friction between the valve seat 5 and the ball core 2, improves the sealing life, reduces the torque of the drive device, reduces energy consumption, and reduces the overall cost of the ball valve.

[0036] To further optimize the above technical solutions, such as Figures 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 includes a small ball 17, a disc spring 18, and a tightening screw 19. Specifically, the side wall of the ball core 2 is provided with a variable diameter through hole that runs through the inner and outer cavities 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. The pressure relief valve 16 is installed in the variable diameter through hole. The small ball 17 moves and abuts against the inside of the variable diameter through hole. The spherical surface of the small ball 17 and the variable diameter through hole on the ball core 2 form a line seal with the conical surface, so as to form the function of closing and opening the end with the smallest diameter of the variable diameter through hole. The tightening screw 19 is screwed into the end of the variable diameter through hole near the outer cavity of the ball core 2. A disc spring 18 is provided between the small ball 17 and the tightening screw 19, which forms a line 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 generates a suitable preload on the variable diameter through hole, thereby controlling the opening and closing of the variable diameter through hole and achieving a seal.

[0037] When the ball valve is in the closed state, and the inner cavity pressure of the ball core 2 is 1.3 times of the outer cavity pressure, the medium pressure pushes the small ball 17 to move away from the ball core 2, and since the inner cavity of the ball core 2 is communicated with the valve cavity 12 at this time, the discharge of the medium in the valve cavity 12 is realized, and the valve cavity 12 is communicated with the gap 13 through the third channel 1101, so that part or all of the medium accumulated in the gap 13 can be discharged at the same time, the pressure of the medium in the valve cavity 12 is within a reasonable range, the small piston 11, the valve seat 5, the main sealing seat 8 and other components are prevented from being in a high load working state all the time, the aging of the components is prevented from being accelerated, the service life is prevented from being shortened, and the stability and safety of the ball valve are ensured.

[0038] The working principle of the bidirectional sealing structure of the application is as follows:

[0039] Firstly, the external force borne by the ball valve is analyzed as follows:

[0040] F 活塞 is the piston force, which is generated by the fluid medium acting on the valve seat, and the external force direction is directed to the ball core;

[0041] F 预紧 is the pre-tightening force, which is generated by the spring pressing the valve seat, and the external force direction is directed to the ball core;

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

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

[0044] F 必需 is the minimum force necessary on the sealing surface when the elastic sealing part of the valve seat and the ball core realize sealing, and the external force direction 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 > 0, the valve seat 5 and the ball core 2 realize sealing.

[0046] When the ball valve is closed and the medium is circulated for the first time, the upstream side of the valve seat 5 has a pressure P1, and since the valve cavity 12 has not yet accumulated medium, 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, and the force F 小活塞 Under the action of the medium, the small piston 11 moves 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, and the sealing force of the ball valve is F 活塞 +F预紧 -F 介质 .

[0047] After the ball valve is used for many times, the valve cavity 12 is filled with medium, and the pressure is P2, at this time, the medium pressure 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, the small piston 11 is pushed to move to the position of the ball core 2, thereby the valve seat 5 is pushed to move to the direction of the ball core 2, that is, F 小活塞 At this time, the sealing force of the ball valve is F 活塞 +F 小活塞 +F 预紧 -F 介质 .

[0048] For the outlet valve seat 5, when the valve cavity 12 has medium, the outlet side has no pressure, 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 the large-diameter ball valve provided by the application can meet the use needs in various working conditions, the ball valve can realize bidirectional sealing, after the pipeline and the ball valve are installed, the system debugging stage is entered. When the pipeline segment between two valves on the pipeline is debugged, the outlet valve seat 5 of the front-end valve needs to realize reverse sealing, and the inlet valve seat 5 of the rear-end valve needs to realize forward sealing, and the bidirectional sealing structure can meet this working condition.

[0050] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bidirectional sealing structure for a large-bore ball valve, characterized by, The ball valve is symmetrically arranged on the water inlet side and the water outlet side, and comprises a valve body (1) and a ball core (2) arranged in the inner cavity of the valve body (1). The ball core (2) is provided with a valve rod (3) rotatably connected with the valve body (1). The bidirectional sealing structure comprises a valve seat (5) movably arranged on the water inlet side and the water outlet side of the ball core (2). The valve seat (5) is provided with a main sealing seat (8) on the side close to the ball core (2). The valve seat (5) is movably connected with a flange (6) through a spring (7) on the side away from the ball core (2). The flange (6), the valve seat (5) and the ball core (2) are movably embedded with a small piston (11). The small piston (11), the flange (6) and the ball core (2) form a valve cavity (12) therebetween. The small piston (11), the valve seat (5) and the flange (6) form a gap (13) therebetween. The valve seat (5) and the ball core (2) are provided with a first channel (501). The flange (6) is provided with a second channel (601) communicating the valve cavity (12) and the inner cavity of the valve body (1). The small piston (11) is provided with a third channel (1101) communicating the valve cavity (12) and the gap (13). When the bidirectional sealing structure on the water inlet side and the water outlet side of the ball core (2) works, 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), so as to push the small piston (11) to move towards the ball core (2), and the small piston (11) pushes the valve seat (5) to move towards the ball core (2). When the small piston (11) exerts a pushing force on the valve seat (5), the small piston (11) can also abut against the ball core (2) finally.

2. The bidirectional sealing structure for large-diameter ball valves according to claim 1, characterized in that, The flange (6) is provided with a groove for installing the spring (7) at the connection with the valve seat (5). The valve seat (5) is provided with a fourth channel (502) communicating the groove and the inner cavity of the valve body (1), which is used for introducing the medium in the inner cavity of the valve body into the groove for installing the spring.

3. The bidirectional sealing structure for large-diameter ball valves according to claim 1, characterized in that, The valve seat (5) is further provided with an auxiliary sealing seat (9) on the side close to the ball core (2). The auxiliary sealing seat (9) is installed on the valve seat (5) through a pressing block (10).

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

5. The bidirectional sealing structure for large-diameter ball valves according to claim 1, characterized in that, The side wall of the ball core (2) is provided with a variable-diameter through hole penetrating the inner cavity and the outer cavity 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 jam screw (19), the small ball (17) movably abuts against the inner part of the variable-diameter through hole, the jam screw (19) is screwed to one end of the variable-diameter through hole close to the outer cavity of the ball core (2), the disc spring (18) is arranged between the small ball (17) and the jam screw (19) and is in linear sealing with the small ball (17), the compression amount of the disc spring (18) is adjusted by the depth of the jam screw (19) 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 large-diameter ball valves according to claim 1, characterized in that, The contact surface of the valve seat (5) and the flange (6) is provided with a plurality of O-rings (15).

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

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

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