Sealing assembly for ball valve

Abstract

The utility model discloses a sealing assembly for a ball valve, which belongs to the technical field of valve manufacture and comprises a valve body and a valve rod mounted on the valve body, a primary sealing structure, valve rod filler and a thrust gasket are sequentially arranged between the valve body and the valve rod, and the primary sealing structure comprises a lower thrust gasket, a compression ring and an upper thrust gasket which are sequentially arranged. According to the ball valve, the primary sealing structure and the valve rod padding are adopted for providing secondary sealing, and the sealing performance of the ball valve can be greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of valve manufacturing, and in particular relates to a sealing component for a ball valve. Background Art

[0002] Traditional ball valve seals generally use two sealing structures, one is O-ring seal and the other is packing seal.

[0003] O-rings have excellent sealing performance, but when designing O-rings, the choice of materials is very restrictive, and many materials are not suitable for making O-rings. This makes O-rings unusable in high-temperature, highly toxic or highly corrosive environments.

[0004] The structure of the existing packing sealing device is as follows: a valve stem mounting hole section and a packing mounting hole section are sequentially arranged in the valve body from bottom to top, the valve stem is installed in the valve stem mounting hole section, the packing is sleeved on the valve stem and located in the packing mounting hole section, the packing gland is sleeved on the valve stem and located above the packing, the packing gland is fixed to the valve body by bolts, and the packing pressure ring is arranged between the packing gland and the packing.

[0005] The existing packing seal device has the following disadvantages: 1. There is no device for reducing the friction coefficient between the valve stem and the valve body. During the opening and closing process of the valve stem, the friction between the valve stem and the valve body is large, which will cause wear of the valve stem and the valve body in a short time, reducing the sealing performance of the device; 2. After a period of use, the packing will wear to a certain extent. The worn packing cannot compensate for the seal, causing the high-temperature medium to leak from the valve stem seal and damage the actuator.

[0006] The existing sealing device has a short effective sealing time. After the seal fails, the leaked high temperature, highly toxic or highly corrosive media may cause harm to the operator and easily lead to safety accidents. Frequent production stops to replace valve sealing components or adjust sealing components not only cause great inconvenience, but also increase production costs.

[0007] A Chinese patent with publication number CN202746747U and publication date 2013-02-20 discloses a self-compensating double packing seal structure, including a valve body and a valve stem mounted on the valve body, and also including a stuffing box A sleeved on the valve stem and fixed on the valve body, and a stuffing box B sleeved on the valve stem and fixed on the stuffing box A. The self-compensating double packing seal structure still has the disadvantage of poor sealing performance. Utility Model Content

[0008] In order to solve the above technical problems, the utility model provides a sealing assembly for a ball valve, wherein the primary sealing structure and the valve stem packing provide a secondary seal, which can greatly improve the sealing performance of the ball valve.

[0009] The purpose of this utility model is achieved through the following technical solutions:

[0010] The sealing assembly comprises a valve body and a valve stem installed on the valve body, wherein a primary sealing structure, a valve stem packing and a thrust gasket are sequentially arranged between the valve body and the valve stem, and the primary sealing structure comprises a lower thrust gasket, a compression ring and an upper thrust gasket which are sequentially arranged.

[0011] Preferably, the lower thrust washer comprises a lower thrust washer body, and the lower thrust washer body is provided with a first protrusion, a second protrusion and a third protrusion.

[0012] Preferably, the first protrusion is used to block the first gap between the valve body and the valve stem, the second protrusion is used to block the second gap between the valve body and the compression ring, and the third protrusion is used to block the third gap between the compression ring and the valve stem.

[0013] Preferably, the upper thrust washer comprises an upper thrust washer body, and the upper thrust washer body is provided with a fourth protrusion, a fifth protrusion and a sixth protrusion.

[0014] Preferably, the fourth protrusion is used to block the second gap between the valve body and the compression ring, the fifth protrusion is used to block the third gap between the compression ring and the valve stem, and the sixth protrusion is used to block the fourth gap between the valve body and the valve stem.

[0015] Preferably, an O-ring is provided between the primary sealing structure and the valve stem packing.

[0016] Preferably, a disc spring is also provided on the thrust washer.

[0017] The beneficial effects of this technical solution are as follows:

[0018] 1. The sealing assembly for a ball valve provided by the utility model has a primary sealing structure and a valve stem packing that provide a secondary seal. The primary sealing structure composed of an upper thrust gasket, a compression ring and a lower thrust gasket. When tightened, the dynamically loaded valve stem will pull up and compress the thrust gasket. When this happens, the material of the lower thrust gasket will be squeezed out between the valve stem and the valve body housing. The surface between the bottom of the lower thrust gasket and the top of the valve stem flange is smooth, and all rotation occurs between these two surfaces, making the thrust gasket "stationary" to produce the best seal; as the rotation continues, the components will enter and keep the sealing performance consistent with use.

[0019] 2. The sealing assembly for the ball valve provided by the utility model can automatically and continuously compress the sealing element in the disc spring to adjust against wear, pressure and temperature fluctuations.

[0020] 3. The sealing assembly for the ball valve provided by the utility model, the arrangement of the O-ring provides a third level of sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the sealing component in the utility model;

[0022] Figure 2 For the utility model Figure 1 The enlarged view of point A in the middle;

[0023] Figure 3 For the utility model Figure 2 The enlarged view of point B in the middle;

[0024] Figure 4 For the utility model Figure 2 Enlarged view of point C in the middle;

[0025] Figure 5 For the utility model Figure 2 The enlarged view of point D in the middle;

[0026] Figure 6 For the utility model Figure 2 Enlarged view of point E in the middle;

[0027] Figure 7 For the utility model Figure 2 The enlarged view of F in the middle;

[0028] Figure 8 For the utility model Figure 2 Enlarged view of G in the middle;

[0029] Fig. 9 This is a schematic diagram of the structure of the ball valve of the utility model;

[0030] Wherein: 1. valve body; 2. valve stem; 3. primary sealing structure; 31. lower thrust gasket; 311. first protrusion; 312. second protrusion; 313. third protrusion; 32. compression ring; 33. upper thrust gasket; 331. fourth protrusion; 332. fifth protrusion; 333. sixth protrusion; 4. valve stem packing; 5. thrust gasket; 6. O-ring; 7. disc spring; 8. left valve body; 9. right valve body; 10. first flow port; 11. rotating chamber; 12. second flow port; 13. ball; 14. valve seat; 15. gland; 16. handle; 17. first valve stem nut; 18. lock saddle; 19. lock trigger; 20. rivet; 21. handle sleeve; 22. stop bolt; 23. second valve stem nut. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the embodiments, but the implementation manner of the present invention is not limited thereto.

[0032] Example 1

[0033] like Figure 1As shown, a sealing assembly for a ball valve includes a valve body 1 and a valve stem 2 installed on the valve body 1, a primary sealing structure 3, a valve stem packing 4 and a thrust gasket 5 are sequentially arranged between the valve body 1 and the valve stem 2, and the primary sealing structure 3 includes a lower thrust gasket 31, a compression ring 32 and an upper thrust gasket 33 which are sequentially arranged.

[0034] The primary sealing structure 3 and the stem packing 4 provide secondary sealing. The primary sealing structure 3 composed of the upper thrust gasket 33, the compression ring 32 and the lower thrust gasket 31, when tightened, the dynamic load valve stem 2 will be pulled up through the thrust gasket 5, thereby compressing the valve stem packing 4 and the A-part component (i.e., the thrust gasket 31, the compression ring 32, and the upper thrust gasket 33). When this happens, the valve stem packing 4 will be squeezed in both directions of the valve body 1 and the valve stem 2, thereby achieving the sealing of the valve stem packing 4 and the valve body 1, and the sealing between the valve stem packing 4 and the valve stem 2; at the same time, the material of the lower thrust gasket 31 will be squeezed out between the valve stem 2 and the outer shell of the valve body 1, and the surface between the bottom of the lower thrust gasket 31 and the top of the valve stem 2 flange is smooth. All rotation occurs between these two surfaces, making the thrust gasket 5 "stationary" to produce the best seal; as the rotation continues; the components will enter and keep the sealing performance consistent with use.

[0035] Example 2

[0036] like Figure 2-Figure 8 As shown, the difference between this embodiment and embodiment 1 is that the lower thrust washer 31 includes a lower thrust washer 31 body, and the lower thrust washer 31 body is provided with a first protrusion 311, a second protrusion 312 and a third protrusion 313. The first protrusion 311 is used to block the first gap between the valve body 1 and the valve stem 2, the second protrusion 312 is used to block the second gap between the valve body 1 and the compression ring 32, and the third protrusion 313 is used to block the third gap between the compression ring 32 and the valve stem 2.

[0037] The upper thrust washer 33 includes an upper thrust washer 33 body, and a fourth protrusion 331, a fifth protrusion 332 and a sixth protrusion 333 are provided on the upper thrust washer 33 body. The fourth protrusion 331 is used to block the second gap between the valve body 1 and the compression ring 32, the fifth protrusion 332 is used to block the third gap between the compression ring 32 and the valve stem 2, and the sixth protrusion 333 is used to block the fourth gap between the valve body 1 and the valve stem 2.

[0038] Multi-stage sealing with up to 6 zones; encapsulated static sealing is achieved on the upper thrust gasket; constant sealing force is transmitted to the valve stem (see arrow), making the primary seal of the valve stem "positive" The lower thrust gasket (50% SS filled PTFE) has excellent wear resistance; the surface finish of the valve stem is better than Ra0.8m (150 coarse sand), which reduces the friction of the seal.

[0039] Wherein, an O-ring 6 is arranged between the primary sealing structure 3 and the valve stem packing 4 .

[0040] The thrust washer 5 is also provided with a disc spring 7. The disc spring 7 is a Belleville washer. The disc spring 7 can automatically and continuously compress the seal and adjust against wear, pressure and temperature fluctuations.

[0041] Example 3

[0042] like Fig. 9 As shown, when the sealing assembly is used in a ball valve, the ball valve includes a valve body 1, the valve body includes a left valve body 8 and a right valve body 9, the left valve body 8 and the right valve body 9 are connected by bolts and nuts, a first flow port 10 is arranged on the left side of the left valve body 8, a rotation chamber 11 is arranged on the right side of the left valve body 8 and the left side of the right valve body 9, a second flow port 12 is arranged on the right side of the right valve body 9, the first flow port 10, the rotation chamber 11 and the second flow port 12 are connected in sequence, a ball 13 is rotatably arranged in the rotation chamber 11, valve seats 14 are arranged on both sides of the ball 13, the top of the ball 13 is connected to the valve stem 2, the valve stem 2 drives the ball 13 to rotate in the rotation chamber 11, and the on-off of the fluid is controlled by rotating the ball 13; a primary sealing structure 3, a valve stem packing 4 and a thrust gasket 5 are arranged in sequence between the valve stem 2 and the right valve body 9, a gland 15 is arranged on the top of the right valve body 9, and the valve stem 2 passes through the upper end of the right valve body 9 and the gland 15 in sequence.

[0043] Wherein, a handle 16 is provided at the upper end of the valve stem 2 .

[0044] The handle 16 is connected to the valve stem 2 via a first valve stem nut 17 ; a lock saddle 18 is provided above the butterfly spring 7 , and the lock saddle 18 is connected to the valve stem 2 via a second valve stem nut 23 to prevent loosening and ensure the output of the butterfly spring 7 .

[0045] The handle 16 is connected to the upper end of the right valve body 9 through a locking trigger 19 and a stop bolt 22 .

[0046] The handle 16 is connected to the handle sleeve 21 via a rivet 20 .

[0047] In the ball valve, the secondary seal is provided by the primary sealing mechanism and the valve stem packing 4, which can greatly improve the sealing performance of the ball valve; the setting of the O-ring 6 provides the third-level seal; the ball valve can be used for critical and dangerous applications in the chemical, petrochemical, oil and gas and related industries. The ball valve has a standard, fireproof and fugitive emission certified design.

[0048] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A sealing assembly for a ball valve, comprising a valve body (1) and a valve stem (2) mounted on the valve body (1), characterized in that: A primary sealing structure (3), a valve stem packing (4) and a thrust gasket (5) are sequentially arranged between the valve body (1) and the valve stem (2); the primary sealing structure (3) comprises a lower thrust gasket (31), a compression ring (32) and an upper thrust gasket (33) which are sequentially arranged.

2. The sealing assembly for a ball valve according to claim 1, characterized in that: The lower thrust washer (31) comprises a lower thrust washer (31) body, on which a first protrusion (311), a second protrusion (312) and a third protrusion (313) are provided.

3. The sealing assembly for a ball valve according to claim 2, characterized in that: The first protrusion (311) is used to seal a first gap between the valve body (1) and the valve stem (2), the second protrusion (312) is used to seal a second gap between the valve body (1) and the compression ring (32), and the third protrusion (313) is used to seal a third gap between the compression ring (32) and the valve stem (2).

4. The sealing assembly for a ball valve according to claim 1, characterized in that: The upper thrust washer (33) comprises an upper thrust washer (33) body, on which a fourth protrusion (331), a fifth protrusion (332) and a sixth protrusion (333) are provided.

5. The sealing assembly for a ball valve according to claim 4, characterized in that: The fourth protrusion (331) is used to block the second gap between the valve body (1) and the compression ring (32), the fifth protrusion (332) is used to block the third gap between the compression ring (32) and the valve stem (2), and the sixth protrusion (333) is used to block the fourth gap between the valve body (1) and the valve stem (2).

6. The sealing assembly for a ball valve according to claim 1, characterized in that: An O-ring (6) is provided between the primary sealing structure (3) and the valve stem packing (4).

7. The sealing assembly for a ball valve according to claim 1, characterized in that: The thrust washer (5) is also provided with a disc spring (7).

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