Ball valve of multi-stage sealing structure

Abstract

A ball valve of a multi-stage sealing structure comprises a valve body, a valve seat, a ball body and a sealing assembly. First and second main spring seats are arranged in the valve body and are respectively connected with first and second radial steps of the valve seat through first and second main springs, so that the stability of the valve seat is enhanced; an axial step space allowing media to enter is designed on the outer ring face of the valve seat, the surface area of a first radial step is large, and sealing is facilitated. According to the sealing assembly, a first sealing groove is formed in an inner ring of a valve seat, a metal sealing seat and an auxiliary spring are arranged in the first sealing groove, and stable pre-tightening force is provided; a second sealing groove is formed in the outer edge, a flexible sealing assembly composed of a triangular sealing ring and a right trapezoid sealing ring is installed, and multiple sealing is achieved. By means of the design, the sealing performance of the ball valve is enhanced, the durability of the valve is improved, and the service life of the valve is prolonged by means of the multiple sealing structures and the optimized sealing face design. In addition, the enhanced pre-tightening force ensures that the valve seat is tightly attached to the ball body, the sealing effect is further improved, and the ball valve can keep excellent sealing performance under various working conditions.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of ball valve, especially a kind of ball valve of multistage sealing structure. BACKGROUND

[0002] Ball valve is widely used in petroleum refining, long-distance pipeline, chemical industry, papermaking, pharmacy, water conservancy and other industries, and its core function is to cut off, distribute and change the flow direction of medium in pipeline.However, under the working condition containing impurity particles, the sealing performance of ball valve faces severe challenges.Specifically, although single soft seal shows good sealing effect at the beginning, impurity particles in medium are easy to invade valve seat sealing surface during valve opening and closing process, leading to soft valve seat wear, which will cause sealing failure after long-term operation, and further affect the normal function of valve.On the other hand, although single hard seal has strong wear resistance, its sealing effect is obviously different from that of soft seal.In addition, under the condition of large pipeline pressure, in order to ensure the sealing performance of ball valve, the traditional single push spring valve seat is often difficult to meet the expected sealing requirement due to the limited sealing pre-tightening force, and there may be the problem of uneven stress on sealing surface, which further affects the sealing effect.Therefore, a new type of valve seat sealing method is needed, which integrates the advantages of soft seal and hard seal and can provide larger and uniform sealing pre-tightening force, to solve the above problems. SUMMARY

[0003] In view of the problems existing in the prior art, the utility model provides a ball valve with multistage sealing structure to solve the problems of poor sealing effect of single hard seal structure and easy wear of single soft seal in the background art, and also can improve the situation that the pre-tightening force provided by single spring is limited or the sealing surface is unevenly stressed, resulting in poor sealing effect.

[0004] The utility model is realized in this way, a kind of ball valve of multistage sealing structure, including valve body, the valve seat being installed in valve body, the ball body being installed in valve body and being matched with valve seat and the sealing assembly being set on valve seat, its characterized in that: two main spring seats are equipped on valve body, and they are first main spring seat and second main spring seat respectively, first radial step of valve seat outer circle surface is installed with first main spring between the first main spring seat of valve body inner wall, and second radial step is installed with second main spring between the second main spring seat of valve body inner wall;First axial step of valve seat outer ring surface is left with a certain distance between valve body inner wall, so that the medium in valve cavity enters, and the surface area of the first radial step of valve seat is greater than the surface area close to the protruding part of ball body;

[0005] The sealing assembly comprises a first sealing groove installed close to the inner ring of the valve seat, a metal sealing seat arranged in the first sealing groove, a secondary spring arranged between the metal sealing seat and the sealing groove, a second sealing groove arranged close to the outer edge of the valve seat, and a flexible sealing assembly installed in the second sealing groove, wherein the flexible sealing assembly comprises a triangular sealing ring and a right-angled trapezoidal sealing ring.

[0006] Preferably, the first main spring, the second main spring and the secondary spring are selected from a helical spring, a butterfly spring or a wave spring.

[0007] Preferably, the second axial step of the outer ring surface of the valve seat is provided with a sealing ring groove and a fireproof ring groove, the fireproof ring groove is close to the side of the ball, an O-shaped sealing ring is installed in the sealing ring groove, and a fireproof ring is installed in the fireproof ring groove.

[0008] Preferably, the uppermost corner of the sealing surface of the valve seat body and / or the lowermost corner of the sealing surface of the metal sealing seat is designed as an acute angle.

[0009] Preferably, the gap range between the uppermost corner of the sealing surface of the valve seat body and / or the lowermost corner of the sealing surface of the metal sealing seat and the ball is set to 0.05-0.5mm.

[0010] The utility model has the advantages and technical effects that the utility model adopts the above technical scheme, and has the following technical effects:

[0011] The multiple sealing structure improves the sealing performance: by combining the soft sealing (triangular sealing ring and right-angled trapezoidal sealing ring) and the hard sealing (metal-to-metal sealing), the good sealing effect is ensured, and the durability and fireproof performance of the sealing are enhanced. This design enables the valve to maintain a tight sealing state under various working conditions.

[0012] The pre-tightening force is enhanced, and the sealing reliability is improved: the springs providing the pre-tightening force of the valve seat are increased from one to three (first main spring, second main spring and secondary spring), which not only significantly improves the pre-tightening force, but also makes the valve seat and the ball fit more closely, and makes the force acting on the sealing surface more uniform. This effectively improves the problems of sealing surface deviation and tightness of sealing edge caused by machining tolerance and other reasons, and further improves the reliability of the sealing.

[0013] The self-cleaning design prolongs the service life: the upper corner of the valve seat and the lower corner of the independent metal sealing seat are designed as acute angles, forming a scraping angle, which can effectively clean the impurities on the surface of the ball and in the medium during the opening and closing of the valve. This self-cleaning design reduces the wear and damage of impurities to the soft sealing structure, thereby prolonging the service life of the valve.

[0014] Fire safety performance enhancement: A fireproof ring groove is arranged on the second axial step of the outer ring surface of the valve seat, and a fireproof ring is installed. This design effectively prevents the leakage of the medium caused by the failure of the O-shaped sealing ring in the case of fire, ensuring the sealing of the valve cavity and providing a strong guarantee for the safe operation of the valve.

[0015] Optimized sealing surface design to improve sealing effect: By accurately calculating and controlling the small gap between the valve seat and the ball, it is ensured that most of the particulate impurities on the surface of the ball can be removed, and at the same time, it is ensured that the opening and closing action of the valve and the ball itself will not be adversely affected. This optimized design further improves the sealing effect and ensures the reliable operation of the valve.

[0016] In summary, the utility model discloses a multiple sealing structure, enhanced pre-tightening force, self-cleaning design, enhanced fire safety performance and optimized sealing surface design, which significantly improves the sealing performance, durability, fire safety and service life of the ball valve. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The utility model discloses a ball valve

[0018] In the drawing, 1, ball; 2, valve seat; 2-1, first sealing groove; 2-2, second sealing groove; 2-3, sealing ring groove; 2-4, fireproof ring groove; 3, right-angled trapezoidal sealing ring; 4, triangular sealing ring; 5, valve body; 5-1, first main spring valve seat; 5-2, second main spring seat; 6, first main spring; 7, fireproof ring; 8, O-shaped sealing ring; 9, second main spring; 10, auxiliary spring; 12, metal sealing seat. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model is further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the utility model and do not limit the utility model.

[0020] Please refer to Figure 1The utility model provides a kind of multi-stage sealing structure ball valve, including valve body 5, the valve seat 2 being installed in valve body, the ball body 1 being installed in valve body and being matched with valve seat and the sealing assembly being arranged on valve seat, it is characterized in that: two main spring seats are provided on valve body 5, respectively first main spring valve seat 5-1 and second main spring seat 5-2, the first radial step of the outer circumferential surface of valve seat 2 is installed with first main spring 6 between the first main spring seat 5-1 of the inner wall of valve body 5, and second radial step is installed with second main spring 9 between the second main spring seat 5-2 of the inner wall of valve body 5;The first axial step of the outer circumferential surface of valve seat 2 is left with a certain distance between the inner wall of valve body 5, and forms medium passage, and the surface area of the first radial step of valve seat 2 is greater than the surface area close to the protruding part of ball body 1.

[0021] The sealing assembly includes the first sealing groove 2-1 installed in the inner ring of the valve seat 2, the metal sealing seat 12 is arranged in the first sealing groove 2-1, and the auxiliary spring 10 is arranged between the metal sealing seat 12 and the sealing groove. The outer edge of the valve seat 2 is also provided with the second sealing groove 2-2, and the flexible sealing assembly is installed in the second sealing groove 2-2. The flexible sealing assembly includes the triangular sealing ring 4 and the right-angled trapezoidal sealing ring 3. The sealing assembly is carefully configured in the inner ring and the outer edge of the valve seat 2. The metal sealing seat 12 is embedded in the first sealing groove 2-1 of the inner ring of the valve seat 2. The auxiliary spring 10 is ingeniously arranged between the metal sealing seat and the sealing groove to enhance the sealing effect. The outer edge of the valve seat 2 is provided with the second sealing groove 2-1, and the flexible sealing assembly composed of the triangular sealing ring 4 and the right-angled trapezoidal sealing ring 3 is installed in the groove.

[0022] The sealing system of the valve seat 2 is composed of two core parts. The primary part is the sealing structure between the valve seat 2 and the ball body 1, which combines the valve seat body 2 made of stainless steel, the independent metal sealing seat 12 (also made of stainless steel), the triangular sealing ring 4 made of rubber, and the right-angled trapezoidal sealing ring 3 made of PTFE plastic. Above the contact sealing surface between the valve seat 2 and the ball body 1, two closely connected sealing grooves, the first sealing groove and the second sealing groove, are carefully designed, which seamlessly connect between them.

[0023] The independent metal sealing seat 12, as a dual role of sealing and cleaning, is located at the bottom of the sealing surface and provides stable pre-tightening force by the auxiliary spring 10 in the groove below the valve seat. The pre-tightening force direction of the auxiliary spring is almost parallel to the contact sealing surface of the metal sealing seat 12 and the ball body 1. This design ensures that the pre-tightening force can be uniformly transmitted to the sealing surface, thereby significantly improving the sealing performance.

[0024] The first sealing groove is equipped with a triangular rubber sealing ring 4, one corner of which closely adheres to the sealing surface, forming the first soft sealing barrier; and the second sealing groove next to it is equipped with a right-angled trapezoidal sealing ring 3, the inclined surface of which closely fits the ball 1, constituting the second soft sealing line. Under the synergistic effect of the two main springs, the valve seat 2 and the ball 1 closely embrace each other, forming a solid hard sealing structure of metal to metal, which is the essence of the first stage of hard sealing. It is worth noting that the sealing surfaces of the triangular sealing ring 4 and the right-angled trapezoidal sealing ring 3 are slightly higher than the metal sealing surface of the valve seat 2, which first contacts and plastically deforms with the ball 1 under the combined action of the spring and the medium pressure, closely adheres to it, and then the metal sealing surface of the valve seat 2 contacts the ball 1, thereby building a soft and hard sealing system with layer-by-layer protection. In addition, the bottom of the valve seat is also equipped with a stainless steel independent metal sealing seat 12 provided with pre-tightening force by the auxiliary spring, which forms a solid guarantee for the second stage of hard sealing between the ball 1.

[0025] The triangular sealing ring 4 and the right-angled trapezoidal sealing ring 3 are located below and above the valve seat 2 main body, respectively. One straight side of the triangular sealing ring closely depends on the long bottom side of the right-angled trapezoidal sealing ring, which not only provides mutual support and compression force for the two, but also effectively prevents the sealing ring from being accidentally squeezed out during the strong spring pre-tightening force and valve opening and closing process. In terms of material selection, the triangular sealing ring 4 is preferably made of rubber, and high molecular materials such as PTFE plastic can also be considered; while the right-angled trapezoidal sealing ring 3 is preferably made of PTFE plastic, and high molecular materials such as nylon are also good choices.

[0026] Preferably, the first main spring 6, the second main spring 9, and the auxiliary spring 10 can be selected from a spiral spring, a butterfly spring, or a wave spring.

[0027] Preferably, the second axial step of the outer ring surface of the valve seat 2 is provided with a sealing ring groove 2-3 and a fireproof ring groove 2-4, and the fireproof ring groove 2-3 is close to the ball 1 side. The sealing ring groove 2-2 is equipped with an O-shaped sealing ring 8, and the fireproof ring groove 2-3 is equipped with a fireproof ring 7. On the outer ring surface of the valve seat 2, the second axial step is ingeniously designed with the sealing ring groove 2-3 and the fireproof ring groove 2-4, and the fireproof ring groove 2-4 is closer to the ball 1 side. In the sealing ring groove 2-3, an O-shaped sealing ring 8 is installed to ensure the reliability of the conventional sealing; and in the fireproof ring groove 2-4, a special fireproof ring 7 is equipped to enhance the fire safety performance of the valve.

[0028] The double sealing structure of the valve seat 2 is integrated with excellent fireproof design concept. The metal-to-metal hard sealing structure between the valve seat 2 and the ball 1 forms the first solid defense line, which can ensure the valve to keep tight sealing state even in the emergency situation that the soft sealing fails due to fire. The sealing structure between the valve seat 2 and the valve body 5 is cleverly added with a fireproof ring through the fireproof ring groove on the second axial step of the valve seat 2. This design effectively prevents the medium leakage caused by the failure of the O-shaped sealing ring in the fire situation, thereby ensuring the sealing of the valve cavity and providing another powerful guarantee for the safe operation of the valve.

[0029] Preferably, the uppermost corners of the main sealing surface of the valve seat 2 and the lowermost corners of the sealing surface of the metal sealing seat 12 are carefully carved into acute angle shape, and the two acute angles form the scraping angle design. In each operation of the valve, the scraping angles play an important role in cleaning the sealing surface, which can effectively block and remove the impurities that may be carried on the surface of the ball and the medium, thereby avoiding the abrasion or damage of the soft sealing structure caused by the impurities.

[0030] In order to ensure that the two scraping angles can play a cleaning role in the operation of the valve without causing unnecessary pressure or damage to the ball 1 due to too close contact, a small gap between the ball 1 and the scraping angles is specially set. The width of the gap is accurately calculated to ensure that most of the particle impurities on the surface of the ball 1 can be removed, and it is also ensured that the operation of the valve and the ball 1 itself will not be adversely affected. Specifically, the gap is strictly controlled within the range of 0.05-0.5mm, which not only reflects the delicacy and ingenuity of the design, but also ensures the reliability and durability of the valve in actual operation.

[0031] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-stage sealing structure ball valve comprising a valve body (5), a valve seat (2) mounted in the valve body, a ball (1) mounted in the valve body and cooperating with the valve seat, and a sealing assembly arranged on the valve seat, characterized in that: Two main spring seats are arranged on the valve body (5), namely a first main spring seat (5-1) and a second main spring seat (5-2), a first main spring (6) is arranged between the first radial step of the outer circumferential surface of the valve seat (2) and the first main spring seat of the inner wall of the valve body (5), and a second main spring (9) is arranged between the second radial step and the second main spring seat of the inner wall of the valve body (5); a certain distance is left between the first axial step of the outer circumferential surface of the valve seat (2) and the inner wall of the valve body (5), so that the medium in the medium cavity of the valve enters, the surface area of the first radial step of the valve seat (2) is greater than the surface area of the protruding part close to the sphere (1), The sealing assembly comprises a first sealing groove (2-1) arranged close to the inner circle of the valve seat, a metal sealing seat (12) is arranged in the first sealing groove, a secondary spring is arranged between the metal sealing seat (12) and the sealing groove, a second sealing groove (2-2) is arranged close to the outer edge of the valve seat, a flexible sealing assembly is arranged in the second sealing groove (2-2), and the flexible sealing assembly comprises a triangular sealing ring (4) and a right-angled trapezoidal sealing ring (3).

2. The multi-stage seal ball valve of claim 1, wherein: The first main spring (6), the second main spring (9) and the secondary spring (10) are selected from a helical spring, a butterfly spring or a wave spring.

3. The multi-stage seal ball valve of claim 1, wherein: The second axial step of the outer circumferential surface of the valve seat (2) is provided with a sealing ring groove (2-3) and a fireproof ring groove (2-4), the fireproof ring groove is close to the sphere side, an O-shaped sealing ring (8) is arranged in the sealing ring groove, and a fireproof ring (7) is arranged in the fireproof ring groove.

4. The multi-stage seal ball valve of claim 1, wherein: The uppermost corner of the main sealing surface of the valve seat (2) and / or the lowermost corner of the sealing surface of the metal sealing seat (12) is designed as an acute angle.

5. The multi-stage seal ball valve of claim 4, wherein: The gap range between the uppermost corner of the main sealing surface of the valve seat (2) and / or the lowermost corner of the sealing surface of the metal sealing seat (12) and the sphere is 0.05-0.5 mm.

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