CN106090284B - A kind of super-large diameter is welded and fixed spherical ball valve double sealing structure entirely - Google Patents

Abstract

The present invention provides a double-seal structure of a full-welded fixed ball valve with an extra-large diameter, including a primary sealing structure and a secondary sealing structure arranged on the connecting surface between the connecting pipe and the ball, and the primary sealing structure and the secondary sealing structure form a A tandem sealing structure arranged sequentially from the inside to the outside. The present invention provides a double-sealed structure of an extra-large-diameter full-welded fixed ball valve, the sealing structure adopts a double-sealed structure, the first-stage sealing structure is close to the edge of the ball valve circulation channel, and plays the role of the main seal; the second-stage sealing structure is used as The leakage protection sealing structure of the first-level sealing structure, when the fluid medium leakage occurs in the first-level sealing, the fluid medium leakage protection sealing is performed by the second-level sealing structure. The two-stage sealing structure works together to significantly improve the sealing performance of the ball valve.

Description

A double-seal structure of an extra-large diameter full-welded fixed ball valve

technical field

The invention relates to the technical field of sealing structure and performance of valves, in particular to a double-sealing structure of an extra-large-diameter full-welded fixed-ball valve, which is applied to an extra-large-diameter full-welded fixed-ball valve to realize bidirectional double-sealing functions.

Background technique

The opening and closing part of the ball valve is a sphere, which is used to rotate 90° around the axis of the valve stem to achieve the purpose of opening and closing. The structure of the ball valve is mainly composed of a valve body, a ball, a sealing structure, an opening and closing transmission mechanism and a supporting structure. Due to the outstanding advantages of small fluid resistance, good sealing performance, high reliability, and fast opening and closing speed, the ball valve not only makes it widely used in general industrial pipelines, but also plays an important role in realizing agricultural modernization, transportation, national defense industry and improving People's living standards and other aspects are also widely used. According to the domestic machinery industry standard, the valve with nominal size DN≥1400mm is an extra large diameter valve. In terms of structural principles, ball valves can be divided into fixed ball valves and floating ball valves. The so-called fixed ball ball valve, that is, the ball is fixed and rotated by the upper and lower support shafts. With the advancement of science and technology and social development, extra-large diameter fully welded ball valves have received more and more attention and design applications. Because it is a fully welded valve body, it can be directly buried in the ground, so that the internal parts of the ball valve will not be corroded, and the service life is long, making the fully welded ball valve especially suitable for heating in cities and towns, transportation of buried pipeline oil and natural gas, and seabed On the long-distance pipeline.

The zero-leakage sealing performance and low opening and closing torque of ball valves have always been the goals pursued by ball valve designers. The sealing index of the ball valve is determined by the internal leakage and external leakage requirements. The national standard stipulates that the sealing performance of the non-metallic sealing ball valve shall be carried out according to the A level of GB/T13927-2008 "General Valve Pressure Test", which requires "no visible leakage during the test duration. "; The aerospace industry standard stipulates that the ball valve used in the ground gas pipeline system "under the pressure condition of 0.05MPa and 1.1 times the nominal pressure, the internal leakage rate should not be greater than 3*10 ^-5 Pa.m ³ /s (no Bubble overflow); under the air pressure condition of 1.1 times the nominal pressure, keep the pressure for 3 minutes, and the external leakage rate should not be greater than 1*10 ^-5 Pa.m ³ /s (no bubble overflow).”

At present, there are many methods for designing the sealing structure of ball valves, some of which enhance the sealing performance by injecting sealing grease, and some improve the sealing performance by innovatively designing the structure of the valve seat and valve body. Chinese patent CN205315765U discloses a fully welded ball valve, the sealing valve seat is an L-shaped structure with a transverse end and a longitudinal end, and a gap groove is provided on the connection angle between the transverse end and the longitudinal end, the sealing valve A medium inlet channel is also provided on the longitudinal end of the seat, and the inner port of the medium inlet channel extends to the notch groove. Chinese patent CN104913078A discloses a fully welded ball valve for oil and gas pipelines. , composed of elastic columns. Although these improvements can play a role in improving the sealing performance to a certain extent, due to the effect of the fluid medium and the influence of the surrounding environment on the sealing structure, the ball valve is prone to fluid medium leakage. Since there is no medium leakage to protect the sealing structure, it cannot reach the final Super high sealing effect.

Contents of the invention

The technical problem to be solved by the present invention is: for extra-large diameter fully welded fixed ball valves, due to the large structural size of the ball valve, the required opening and closing torque is very large, in order to have a small opening and closing torque, it is necessary to reasonably control the sealing surface However, it is difficult to properly control the sealing specific pressure of super large diameter ball valves, and the problem of medium leakage is easy to occur. Therefore, in view of the technical problem that the sealing structure of the ball valve is difficult to ensure a good seal and the medium leaks, the present invention provides a double-sealing structure of an extra-large diameter full-welded fixed ball valve, and a two-stage sealing mechanism is set on the spherical surface of the ball valve to improve the sealing performance of the ball valve .

The technical solution adopted by the present invention to solve the technical problem is: a double-seal structure of an extra-large-diameter full-welded fixed ball valve, including a primary sealing structure and a secondary sealing structure arranged on the connecting surface between the connecting pipe and the ball. The first-level sealing structure and the second-level sealing structure form a series-type sealing structure arranged in sequence from the inside to the outside. It adopts a two-stage sealing structure in series from the inside to the outside. When the medium leaks in the first-stage sealing structure, the second-stage sealing structure will protect the medium leakage and significantly improve the sealing performance of the ball valve.

Further, the primary sealing structure is the main sealing structure close to the ball valve communication channel, including a first ball cushion and a first ball cushion seat, one end of the first ball cushion seat is connected to the connecting pipe, and the other end is provided with a first One end of the first ball pad is placed in the first groove. According to the design requirements, the initial sealing specific pressure of the ball pad is determined, and the first ball pad and the ball are controlled by the positioning of the assembly seam to achieve Due to the effect of the initial pre-tightening seal, the other end of the first ball cushion is in close contact with the surface of the sphere. The primary sealing structure is composed of a first ball cushion and a first ball cushion seat arranged between the connecting pipe and the sphere, and near the edge of the ball valve flow channel, the first ball cushion is closely attached to the sphere to achieve a primary seal .

Further, in order to fit and seal better, the end of the first ball pad that fits with the sphere has a first arc-shaped surface that matches the surface of the sphere.

Preferably, the first groove is a U-shaped groove.

Further, in order to make the first ball cushion of the primary sealing structure generate pressure toward the ball to make the fit more tightly, an annular groove is provided on the inner wall of the connection between the connecting pipe and the first ball cushion seat, and the The inner wall of the connecting pipe is flush with the inner wall of the first ball seat. The sealing of the valve mainly depends on the fluid medium acting on the first ball pad seat so that the first ball pad acts on the pressure of the ball to achieve a sealing effect. In order to ensure the tight fit between the first ball pad and the ball, the first ball pad An annular groove is set on the connecting surface of the seat and the connecting pipe. When a medium flows through the channel, the annular groove is filled with medium, and the first ball cushion seat and the first ball cushion generate a pressing force on the surface of the sphere in turn, further The sealing effect is improved, and the inner wall is flush to reduce the resistance to the medium.

Further, the secondary sealing structure includes a second ball cushion and a second ball cushion seat, one end of the second ball cushion seat is connected to the connecting pipe, and the other end is provided with a second groove, and the second ball cushion seat One end is placed in the second groove, the other end of the second ball pad is attached to the surface of the sphere, and the outer side of the second ball pad is connected to the connecting pipe.

Further, the secondary sealing structure also includes a first sealing ring, a second sealing ring and a third sealing ring, and the connecting end of the second ball gasket and the connecting pipe is arranged in sequence along the axial direction of the connecting pipe. There are a first annular groove and a second annular groove, the first sealing ring is placed in the first annular groove, the second sealing ring is placed in the second annular groove, and the connecting pipe is provided with The third annular groove, the second ball seat is provided with a boss, the third sealing ring is placed in the third annular groove, and the boss is inserted into the third annular groove to make The third sealing ring is closed in the third annular groove.

Preferably, the first sealing ring, the second sealing ring and the third sealing ring are all O-rings.

Further, the secondary sealing structure also includes a plurality of pre-tension springs, the pre-tension springs are located outside the third sealing ring, and the side of the connecting pipe opposite to the second ball seat is provided with a number equal to There are blind holes with the same number of pre-tightening springs, one end of the pre-tightening spring is placed in the blind hole, and the other end abuts on the second ball cushion seat, and the elastic force of the pre-tightening spring passes through the first The second ball pad makes the second ball pad fit closely with the surface of the sphere.

Furthermore, in order to fit and seal better, the end of the second ball pad that fits with the sphere has a second arc-shaped surface that matches the surface of the sphere.

Preferably, the second groove is an L-shaped groove.

The secondary sealing structure is arranged on the outside of the primary sealing mechanism, and mainly consists of a set of pre-tightening springs, a second ball pad, a second ball pad seat and three side wall sealing rings, among which the pre-tightening spring provides the initial sealing pre-load. The tightening force makes the second ball cushion close to the sphere, and the side wall sealing ring is arranged on the connecting surface of the connecting pipe to prevent the fluid medium from leaking along the inner wall of the connecting pipe and play a role of sealing.

Further, a pipe is welded at the end of the connecting pipe. The welding connection method improves the strength and reliability of the connection, and also contributes to sealing.

The present invention provides a double-sealed structure of an extra-large-diameter full-welded fixed ball valve, which has the following advantages:

(1) Significantly improve the sealing performance: the sealing structure adopts a double-seal structure, the first-stage sealing structure is close to the edge of the ball valve circulation channel, and plays the role of the main seal; the second-stage sealing structure is used as the leakage protection seal of the first-stage sealing structure structure, when the fluid medium leakage occurs in the first level seal, the fluid medium leakage protection seal is carried out by the second level sealing structure. The pre-tightening spring provides the initial sealing pre-tightening force, and the O-ring on the side wall plays the role of sealing that the fluid medium cannot leak through the outer wall of the connecting pipe. The two sealing structures work together to significantly improve the sealing performance of the ball valve;

(2) The sealing structure is simple and easy to manufacture: firstly, the structure of the ball cushion seat and the ball cushion is simple, without complicated radians and special corners, which is convenient for processing and manufacturing; secondly, the two ball cushion seats are assembled together on a connecting pipe, and the structure Simple and easy to install.

Description of drawings

The present invention will be further described below in conjunction with drawings and embodiments.

Fig. 1 is the structural representation of half of ball valve of the present invention;

FIG. 2 is an enlarged structural schematic diagram of the double sealing structure of A in FIG. 1 .

In the figure: 1. pipeline, 2. connecting pipe, 3. sphere, 4. circulation channel, 5. the first ball cushion, 6. the first ball cushion seat, 7. the first groove, 8. preload spring, 9 , the second ball cushion, 10, the second ball cushion seat, 11, the first sealing ring, 12, the second sealing ring, 13, the third sealing ring, 14, the second groove, 15, the first annular groove, 16 , the second annular groove, 17, the boss, 18, the third annular groove, 19, the blind hole, 20, the annular groove.

Detailed ways

The present invention will be described in detail in conjunction with accompanying drawing now. This figure is a simplified schematic diagram only illustrating the basic structure of the present invention in a schematic manner, so it only shows the components relevant to the present invention.

As shown in Figure 1, the ball valve involved in the present invention adopts a fully welded connection method, which has significant advantages such as no leakage, maintenance-free, buried, good rigidity, light weight and long life. The ball 3 is supported by two upper and lower shafts Fixed rotation, the ball valve adopts a symmetrical structure as a whole, and the design of the sealing structure is also a symmetrical structure.

As shown in Figure 2, a double-sealed structure of an extra large-diameter full-welded fixed ball valve of the present invention includes a pipe 1, a connecting pipe 2, a sphere 3, and a primary sealing structure arranged on the connecting surface between the connecting pipe 2 and the sphere 3 and a secondary sealing structure, the primary sealing structure and the secondary sealing structure form a serial sealing structure arranged in sequence from the inside to the outside, and the pipeline 1 and the connecting pipe 2 are welded and connected.

The primary sealing structure is close to the ball valve flow channel 4 as the main sealing structure, including the first ball cushion 5 and the first ball cushion seat 6, the first ball cushion seat 6 is a circular structure with a rectangular cross section, the first ball cushion One end of the seat 6 is connected to the connecting pipe 2, and the other end is provided with a first groove 7, the first groove 7 is a U-shaped groove, and the first ball pad 5 is a ring structure with a right-angled trapezoidal section. One end of the right-angled waist of the first ball pad 5 is placed in the first groove 7, and one end of the oblique waist of the first ball pad 5 is provided with a first arc surface matched with the surface of the sphere 3. The first ball pad 5 Through the first arc surface and the surface of the sphere 3 closely fit, the inner wall of the connection between the connecting pipe 2 and the first ball seat 6 is provided with an annular groove 20, and the inner wall of the connecting pipe 2 and the first ball seat 6 The inner wall is flush.

The secondary sealing structure includes a set of preload springs 8, a second ball pad 9, a second ball pad seat 10 and three O-rings, and the three O-rings are respectively the first sealing ring 11, The second sealing ring 12 and the third sealing ring 13 .

The second ball cushion 10 is an annular structure with an inverted T shape in section, the pre-tension spring 8 and the second ball cushion 9 are located on both sides of the second ball cushion 10 respectively, and the second ball cushion 10 is close to the side of the ball 3 A second groove 14 is provided, and the second groove 14 is an L-shaped groove, and one end of the second ball pad 9 is placed in the second groove 14, and the second ball pad 9 and the ball 3 The attached end has a second arc surface matched with the surface of the sphere 3 , and the second ball pad 9 closely fits with the surface of the sphere 3 through the second arc surface.

The outer side of the second ball pad 9 is attached to the connecting pipe 2, and the connecting surface between the second ball pad 9 and the connecting pipe 2 is provided with a first annular groove 15 and a The second annular groove 16 , the first sealing ring 11 is placed in the first annular groove 15 , and the second sealing ring 12 is placed in the second annular groove 16 .

A boss 17 is provided on the side near the connecting pipe 2 below the second ball cushion seat 10, and a third annular groove 18 is arranged on the position opposite to the boss 17 of the connecting pipe 2. The third seal The ring 13 is placed in the third annular groove 18 , and the boss 17 is inserted into the third annular groove 18 to seal the third sealing ring 13 in the third annular groove 18 .

The pre-tension spring 8 is located outside the third sealing ring 13, and the side of the connecting pipe 2 opposite to the second ball seat 10 is provided with the same number of blind holes 19 as the number of the pre-tension spring 8 , one end of the pre-tightening spring 8 is placed in the blind hole 19, and the other end abuts on the second ball cushion 10, and the elastic force of the pre-tightening spring 8 is made by the second ball cushion 10. The second ball pad 9 is in close contact with the surface of the ball 3 , and the preload springs 8 and blind holes 19 are evenly distributed along the circumference of the connecting pipe 2 .

Inspired by the ideal embodiment according to the present invention, through the above description, relevant workers can make various changes and modifications without departing from the scope of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims (8)

1. A double sealing structure of an extra-large diameter full-welded fixed ball valve, characterized in that: it includes a primary sealing structure and a secondary sealing structure arranged on the connecting surface of the connecting pipe (2) and the sphere (3), the one The first-level sealing structure and the second-level sealing structure form a serial sealing structure arranged sequentially from the inside to the outside; The secondary sealing structure includes a second ball cushion (9) and a second ball cushion seat (10). One end of the second ball cushion seat (10) is connected to the connecting pipe (2), and the other end is provided with a second ball cushion seat (10). Two grooves (14), one end of the second ball pad (9) is placed in the second groove (14), and the other end of the second ball pad (9) is attached to the surface of the sphere (3) close, and the outer side of the second ball pad (9) is connected with the connecting pipe (2); The secondary sealing structure also includes a first sealing ring (11), a second sealing ring (12) and a third sealing ring (13), and the connection between the second ball gasket (9) and the connecting pipe (2) A first annular groove (15) and a second annular groove (16) are sequentially provided on the connecting end along the axial direction of the connecting pipe (2), and the first sealing ring (11) is placed in the first annular groove (15), the second sealing ring (12) is placed in the second annular groove (16), the connecting pipe (2) is provided with a third annular groove, and the second ball seat ( 10) is provided with a boss (17), the third sealing ring (13) is placed in the third annular groove (18), and the boss (17) is inserted into the third annular groove (18) to seal the third sealing ring (13) in the third annular groove. 2. The extra-large caliber all-welded fixed ball valve double sealing structure according to claim 1, characterized in that: the primary sealing structure is close to the ball valve circulation channel (4) as the main sealing structure, including the first ball pad (5) and the first ball cushion (6), one end of the first ball cushion (6) is connected to the connecting pipe (2), and the other end is provided with a first groove (7), and the first ball cushion ( 5) One end is placed in the first groove (7), and the other end of the first ball pad (5) is pressed against the surface of the ball (3). 3. The double-sealing structure of the extra-large-diameter full-welded fixed ball valve according to claim 2, characterized in that: the end of the first ball pad (5) attached to the ball (3) has a joint with the ball ( 3) The first arcuate surface for surface matching. 4. The double-sealing structure of the extra-large-diameter full-welded trunnion ball valve according to claim 3, characterized in that: the first groove (7) is a U-shaped groove. 5. The extra-large diameter full-welded fixed ball valve double-seal structure according to claim 2, characterized in that: the inner wall of the connection between the connecting pipe (2) and the first ball cushion seat (6) is provided with a ring groove (20), and the inner wall of the connecting pipe (2) is flush with the inner wall of the first ball seat (6). 6. The extra-large caliber all-welded trunnion ball valve double-sealing structure according to claim 1, characterized in that: the first sealing ring (11), the second sealing ring (12) and the third sealing ring (13) are all For O-ring seals. 7. The extra-large diameter all-welded trunnion ball valve double-sealing structure according to claim 1, characterized in that: the secondary sealing structure further includes a plurality of pre-tension springs (8), and the pre-tension springs (8) are located at On the outside of the third sealing ring (13), the side of the connecting pipe (2) opposite to the second ball seat (10) is provided with the same number of blind holes as the number of the pre-tension springs (8) (19), one end of the pre-tension spring (8) is placed in the blind hole (19), and the other end abuts against the second ball cushion seat (10), the pre-tension spring (8) The elastic force makes the second ball cushion (9) closely adhere to the surface of the ball (3) through the second ball cushion seat (10). 8. The double-sealing structure of the extra-large-diameter full-welded fixed ball valve according to claim 7, characterized in that: the end of the second ball pad (9) that fits with the ball (3) has a joint with the ball ( 3) A second curved surface for surface matching.