Bellow stop valve

Abstract

The application discloses a corrugated pipe stop valve, which comprises a valve body, a valve rod, a corrugated sleeve and a sealing packing assembly, and the core of the valve is that a pre-tightening assembly is arranged in the valve body; when the corrugated sleeve is normal, a top pressing plate of the pre-tightening assembly is located between an inserting rod of a locking rod assembly and the valve rod; once the corrugated sleeve is broken, the medium pressure pushes the top pressing plate to move upwards, on one hand, the sealing packing assembly is actively pressed to form a reliable second seal; on the other hand, the movable top pressing plate releases the restriction on the inserting rod, so that the inserting rod extends and abuts against a stage of the valve rod under the action of an elastic element. The structure can lock the valve rod after the valve is closed again after the corrugated sleeve is broken, directly indicates that the corrugated pipe is broken through a mechanical mode, does not need to add electronic elements, and improves the safety and maintenance convenience of the valve.

Description

Technical Field

[0001] This invention relates to the field of bellows gate valve technology, and more specifically to bellows gate valves. Background Technology

[0002] Bellows gate valves are widely used in high-safety-requirement applications such as petroleum and chemical industries. They achieve sealing by isolating the medium through bellows, supplemented by a packing assembly as a backup seal. The packing assembly, positioned above the bellows and pressed tightly by a packing gland, serves as a backup seal. When the bellows is intact, the packing assembly bears minimal medium pressure and acts only as a backup. In the event of an accidental rupture of the bellows, the medium travels upwards along the valve stem, and the packing assembly is pressed tightly by the medium pressure, forming a second line of defense to prevent leakage.

[0003] However, existing technologies have the following drawbacks:

[0004] 1. Deterioration of packing leads to failure of backup seal: When backup packing is left unpressurized and idle for a long time, it is prone to hardening and loss of elasticity. When the bellows ruptures unexpectedly, the deteriorated packing cannot respond quickly and form an effective seal, which can easily cause leakage of the medium and poses a serious safety hazard under dangerous conditions.

[0005] 2. High degree of concealment of faults: There is no intuitive mechanical feedback mechanism after the bellows ruptures, making it difficult for operators to know in time, causing the valve to continue to operate without the protection of the main seal;

[0006] 3. Existing detection solutions are complex: In order to solve the problem of fault detection, conventional designs usually require the addition of complex pressure sensors or media triggering devices inside the valve, which increases the complexity of the structure and maintenance costs. Summary of the Invention

[0007] In view of the prior art, the purpose of this invention is to provide a bellows gate valve with a mechanical feedback structure, which can enhance the packing sealing effect after the bellows ruptures, and can automatically lock the valve stem after the next valve closure to alert the operator of the presence of leakage.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a bellows gate valve, comprising a valve body, a valve stem, a bellows sleeve, a sealing packing assembly, and a drive unit. The valve body is provided with a pre-tightening assembly, the upper end of which abuts against the sealing packing assembly, and the lower end connected to the bellows sleeve. The upper end of the valve stem extends out of the valve body and connects to the drive unit, while the lower end is provided with a valve core. The valve core includes a valve ball that seals the medium flow channel with the valve seat inside the valve body, and a valve plate fixed to the valve stem. The upper end of the bellows sleeve is connected to the pre-tightening assembly, and the lower end is connected to the valve plate. The pre-tightening assembly includes a top pressure plate and a locking rod assembly. The pre-tightening assembly is located inside the bellows sleeve. The locking rod assembly includes a rod extending relative to the valve stem and a pre-compression elastic element that elastically pushes the rod out. In the normal state of the bellows sleeve, the top pressure plate is between the rod and the valve stem. After the bellows sleeve ruptures, the medium pressure pushes the top pressure plate to move and release the restriction. The rod extends under the push of the pre-compression elastic element and abuts against a step provided on the valve stem to restrict the upward movement of the valve stem.

[0009] As a further feature of the above scheme, the upper and lower ends of the corrugated sleeve are respectively provided with welding rings for sealing the packing assembly and the valve plate for welding and fixing. The valve plate is also provided with an exhaust port, which discharges the gas in the cavity formed by the outside of the corrugated sleeve and the valve body when the valve plate compresses the corrugated sleeve.

[0010] As a further provision of the above scheme, the pressure of the inert gas inside the corrugated sleeve in the compressed state is less than the pressure required to push the top pressure plate away from the insert rod and the valve stem, and the pressure of the medium transported in the medium flow channel is greater than the pressure required to push the top pressure plate away from the insert rod and the valve stem.

[0011] As a further feature of the above scheme, the corrugated sleeve is configured as an inverted cone structure with a larger upper part and a smaller lower part, and the pleats on the outer surface of the corrugated sleeve extend spirally from top to bottom.

[0012] As a further provision of the above scheme, the sealing packing assembly includes a packing ring, a packing sleeve, and a packing element. The upper end of the top pressure plate abuts against the lower end of the packing element, the packing ring bolts are locked onto the packing sleeve, and the packing sleeve is bolted and sealed relative to the valve body.

[0013] As a further provision of the above scheme, the locking rod assembly is provided with several sets of sealing packing assemblies distributed on the outer circumference of the valve stem. The sealing packing assembly is also provided with a movable groove for inserting the rod and a sealing cover for closing the movable groove. The sealing cover is used to seal the movable groove and the valve body cavity by bolts and annular sealing rings.

[0014] As a further provision of the above scheme, the valve core includes a hemispherical sleeve and a sealing ball core. The upper end of the hemispherical sleeve is connected to the valve stem, and the lower end is open to accommodate the sealing ball core. The sealing ball core is movably disposed relative to the hemispherical sleeve. The valve seat includes a sealing abutment cone surface with a size matching the sealing ball core. The valve seat is also provided with a reverse pressure part, which is disposed directly opposite the sealing ball core. It is used to deform the valve seat to fit the inner wall of the valve body through the squeezing force of the sealing ball core when the sealing ball core approaches the sealing medium flow channel relative to the valve seat.

[0015] As a further provision of the above scheme, the reverse pressure section includes an upper arched portion and a flat portion with a concave groove, the concave groove abutting against the sealing ball core, and the upper arched portion used to deform and disperse the pressure to the valve seat sidewall.

[0016] Beneficial Effects: Compared with existing technologies, this invention achieves dual safety protection through structural optimization without the need for additional electronic detection components. When the bellows ruptures, the medium pressure directly pushes the top pressure plate of the pre-tightening assembly upward. On the one hand, the upward movement of the top pressure plate squeezes the sealing packing assembly above, actively compressing the packing. Compared with the traditional passive pressure backup sealing scheme, this can more quickly form a reliable second sealing line, preventing medium leakage and solving the problem of sealing failure after long-term idle deterioration of the packing. On the other hand, after the top pressure plate shifts and releases the restriction on the insert rod, the insert rod will extend to the stage of abutting the valve stem under the action of the pre-compression elastic element. When the operator completes the operation to close the valve, the valve stem is locked and cannot be opened upward again, intuitively indicating to the operator that the bellows has ruptured and needs to be repaired and replaced in time. This solves the problem of the bellows rupture being hidden and difficult to detect in time, greatly improving the safety of valve use. At the same time, the overall structure is a purely mechanical design, which does not require complex sensing components, resulting in lower processing and maintenance costs and lower production process modification costs for adapting to existing valves. The movable, floating sealing ball core, combined with the valve seat with reverse pressure section, can further improve the sealing reliability at the valve core, reduce the risk of media leakage, and adapt to the use requirements of high-pressure hazardous gas media. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the bellows stop valve structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the bellows stop valve of the present invention.

[0019] Figure 3 This is a schematic diagram of the pre-tightening assembly of the bellows gate valve of the present invention.

[0020] Figure 4 This is a schematic diagram of the valve seat inside the valve body of the present invention.

[0021] Reference numerals: 1. Valve body; 11. Medium flow channel; 12. Valve seat; 121. Sealing contact cone surface; 122. Reverse pressure section; 2. Valve stem; 21. Valve core; 22. Valve ball; 23. Valve plate; 25. Stage; 26. Hemispherical sleeve; 27. Sealing ball core; 29. ​​Exhaust port; 3. Bellows sleeve; 31. Welded ring; 4. Sealing packing assembly; 41. Packing pressure ring; 42. Packing sleeve; 43. Packing element; 5. Drive unit; 6. Preload assembly; 61. Top pressure plate; 62. Insert rod; 63. Locking rod assembly; 64. Preload elastic element; 67. Sealing cover; 68. Movable groove. Detailed Implementation

[0022] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other.

[0023] like Figure 1-4 The bellows gate valve shown includes a valve body 1, a valve stem 2, a bellows sleeve 3, a sealing packing assembly 4, and a drive unit 5. The valve body 1 contains a pre-tightening assembly 6, the upper end of which abuts against the sealing packing assembly 4, and the lower end of which connects to the bellows sleeve 3. The upper end of the valve stem 2 extends out of the valve body 1 and connects to the drive unit 5, while the lower end contains a valve core 21. The valve core 21 includes a valve ball 22 that seals against the valve seat 12 inside the valve body 1 to block the medium flow channel 11, and a valve plate 23 fixed to the valve stem 2. The upper end of the bellows sleeve 3 is connected to the pre-tightening assembly 6, and the lower end is connected to the valve plate 23. The pre-tightening assembly 6 includes a top pressure plate 61 and a locking rod assembly 63. The pre-tightening assembly 6 is located inside the bellows sleeve 3. The locking rod assembly 63 includes a rod 62 extending relative to the valve stem 2 and a pre-compression elastic member 64 that elastically pushes the rod 62 to extend. In the normal state of the bellows sleeve 3, the top pressure plate 61 is between the rod 62 and the valve stem 2. After the bellows sleeve 3 ruptures, the medium pressure pushes the top pressure plate 61 to move and release the restriction. The rod 62 extends under the push of the pre-compression elastic member 64 and is used to abut against the step 25 provided on the valve stem 2 to restrict the upward movement of the valve stem 2.

[0024] As a further provision of the above scheme, the upper and lower ends of the corrugated sleeve 3 are respectively provided with welding rings 31 and welded to the sealing packing assembly 4 and valve plate 23. The valve plate 23 is also provided with an exhaust port 29, which discharges the gas in the cavity formed by the outside of the corrugated sleeve 3 and the valve body 1 when the valve plate 23 compresses the corrugated sleeve 3.

[0025] As a further provision of the above scheme, the pressure of the inert gas inside the corrugated sleeve 3 in the compressed state is less than the pressure required to push the top pressure plate 61 away from the insert rod 62 and the valve stem 2, and the pressure of the medium transported in the medium flow channel 11 is greater than the pressure required to push the top pressure plate 61 away from the insert rod 62 and the valve stem 2.

[0026] As a further feature of the above scheme, the corrugated sleeve 3 is configured as an inverted cone structure with a larger upper part and a smaller lower part, and the pleats on the outer surface of the corrugated sleeve 3 extend spirally from top to bottom.

[0027] As a further provision of the above scheme, the sealing packing assembly 4 includes a packing pressure ring 41, a packing sleeve 42, and a packing element 43. The upper end of the top pressure plate 61 abuts against the lower end of the packing element 43, the packing pressure ring 41 is bolted to the packing sleeve 42, and the packing sleeve 42 is bolted to the valve body 1 for sealing installation.

[0028] As a further provision of the above scheme, the locking rod assembly 63 is provided with several sets of sealing packing assemblies 4 distributed on the outer circumference of the valve stem 2. The sealing packing assembly 4 is also provided with a movable groove 68 for inserting the rod 62 and a sealing cover 67 for closing the movable groove 68. The sealing cover 67 is provided to seal the movable groove 68 and the inner cavity of the valve body 1 by bolts and annular sealing rings.

[0029] As a further provision of the above scheme, the valve core 21 includes a hemispherical sleeve 26 and a sealing ball core 27. The upper end of the hemispherical sleeve 26 is connected to the valve stem 2, and the lower end is open to accommodate the sealing ball core 27. The sealing ball core 27 is movably disposed relative to the hemispherical sleeve 26. The valve seat 12 includes a sealing abutment cone surface 121 with a size matching the sealing ball core 27. The valve seat 12 is also provided with a reverse pressure part 122, which is disposed directly opposite to the sealing ball core 27. It is used to use the squeezing force of the sealing ball core 27 to make the valve seat 12 conform to the inner wall of the valve body 1 when the sealing ball core 27 is close to the blocking medium flow channel 11 relative to the valve seat 12.

[0030] As a further provision of the above scheme, the reverse pressure part 122 includes an upper arched part and a flat part 124 with a concave groove 123. The concave groove 123 abuts against the sealing ball core 27, and the upper arched part is used to deform and disperse the pressure to the side wall of the valve seat 12.

[0031] The bellows shut-off valve of the present invention, as follows: Figures 1 to 4 As shown, it mainly includes valve body 1, valve stem 2, bellows sleeve 3, sealing packing assembly 4, and drive unit 5.

[0032] Furthermore, the valve body 1 is provided with a pre-tightening assembly 6. The upper end of the pre-tightening assembly 6 abuts against the sealing packing assembly 4, and the lower end is connected to the bellows sleeve 3. The pre-tightening assembly 6 is the core of realizing the dual protection function of the present invention. It includes a top pressure plate 61 and a locking rod assembly 63. The upper end of the valve stem 2 extends out of the valve body 1 and is connected to the drive unit 5, while the lower end is provided with a valve core 21. The valve core 21 includes a valve ball 22 and a valve plate 23. The valve ball 22 is used to cooperate with the valve seat 12 in the valve body 1 to seal and block the medium flow channel 11. The valve plate 23 is fixed on the valve stem 2. The upper end of the bellows sleeve 3 is welded to the sealing packing assembly 4, and the lower end is welded to the valve plate 23, thereby isolating the medium from the valve stem 2.

[0033] The locking rod assembly 63 of the pre-tightening assembly 6 consists of a plunger 62 and a pre-compression elastic element 64. The plunger 62 can extend relative to the valve stem 2 under the push of the pre-compression elastic element 64. The extended plunger 62 forms a limit with the stage 25 of the valve stem 2, so the valve stem 2 cannot be opened again after the valve is sealed again, as described above.

[0034] In this embodiment, when the bellows sleeve 3 is in its normal state, the top pressure plate 61 is partially stuck between the insert rod 62 and the valve stem 2, restricting the insert rod 62 from extending. At this time, the sealing packing assembly 4 presses against the top pressure plate 61. However, once the bellows sleeve 3 ruptures, the medium pressure inside the valve body 1 will overcome the reaction force and quickly push the top pressure plate 61 upward, thereby releasing the restriction on the insert rod 62. At this time, the insert rod 62 extends under the action of the pre-compression elastic member 64, and its end abuts against the small diameter part of the valve stem 2, forming an axial limit with the stepped stage 25 provided on it. Thus, after the valve stem 2 moves downward again, it cannot move upward again, preparing for the subsequent locking action.

[0035] The working process of this invention embodies its unique triple protection mechanism:

[0036] First layer of protection: continuous sealing

[0037] When the bellows sleeve 3 is in normal condition, it forms an isolation between the medium and the valve stem 2;

[0038] Second layer of protection: Actively enhanced sealing

[0039] When the corrugated sleeve 3 ruptures and fails to isolate, the medium pressure pushes the top pressure plate 61 upward. The upper end of the top pressure plate 61 will actively and directly squeeze the pre-tightened sealing packing assembly 4 above. This active pressure method can ensure that the sealing packing assembly 4 is quickly and reliably pressed (the stronger the medium pressure, the better the sealing effect), immediately forming an effective second sealing line of defense, effectively preventing medium leakage, and solving the problem that traditional packing may deteriorate due to long-term idleness, leading to sealing failure.

[0040] Third layer of protection: Mechanical feedback and valve stem locking

[0041] As the top pressure plate 61 moves upward to release the restriction on the insert rod 62, the insert rod 62 extends under the action of the pre-compression elastic element 64. When the operator completes the operation and closes the valve downward, the platform 25 on the valve stem 2 will move to contact the extended insert rod 62. When attempting to open the valve again, i.e., pulling the valve stem upward, the insert rod 62 will be stuck in the platform 25 due to its radial extension, restricting the axial rise of the valve stem 2, thereby mechanically locking the valve stem 2 and preventing it from moving upward. This inability to open provides the operator with intuitive mechanical feedback, clearly indicating that the bellows has ruptured and the valve needs maintenance.

[0042] Corrugated sleeve 3 and valve plate 23: as Figure 2 As shown, the upper and lower ends of the bellows sleeve 3 are welded and fixed to the lower part of the sealing packing assembly 4 and the valve plate 23 by welding rings 31, respectively, to ensure the airtightness of the connection. The valve plate 23 is also provided with an exhaust port 29, which is used to discharge the gas in the cavity between the outside of the bellows sleeve 3 and the inner wall of the valve body 1 when the valve plate 23 compresses the bellows sleeve 3 downward, so as to avoid the back pressure caused by gas compression affecting the valve closure.

[0043] Pressure setting: To ensure reliable triggering of the above mechanism, the present invention has made a precise setting of the pressure. The inert gas filled inside the bellows 3 has a pressure that is less than the minimum pressure required to push the top pressure plate 61 upward, even when the valve is closed and the bellows 3 is compressed. Meanwhile, the pressure of the medium transported in the medium flow channel 11 is much greater than the triggering pressure. In this way, the top pressure plate 61 can only be reliably pushed when the medium enters the inside of the bellows 3.

[0044] like Figure 2 As shown, the corrugated sleeve 3 has an overall inverted conical structure that is larger at the top and smaller at the bottom, and the pleats on its outer surface extend in a spiral shape from top to bottom. This design helps to improve the expansion and contraction stability and fatigue resistance of the corrugated sleeve.

[0045] like Figure 3 As shown, the sealing packing assembly 4 includes a packing ring 41, a packing sleeve 42, and a packing element 43. The upper end of the top pressure plate 61 directly abuts against the lower end of the packing element 43. The packing ring 41 is locked to the packing sleeve 42 by bolts, and the packing sleeve 42 is then locked and sealed relative to the valve body 1 by bolts.

[0046] Furthermore, the locking rod assembly 63 of the present invention can be provided in several groups and distributed along the circumferential direction of the valve rod 2. The sealing packing assembly 4 is correspondingly provided with a movable groove 68 for the insertion rod 62 to move, and is closed by a sealing cover 67. The sealing cover 67 achieves sealing with the inner cavity of the valve body 1 by bolts and an annular sealing ring.

[0047] like Figure 2 and Figure 4 As shown, the valve ball 22 of the valve core 21 is specifically composed of a hemispherical sleeve 26 and a sealing ball core 27. The upper end of the hemispherical sleeve 26 is connected to the valve stem 2, and a movable sealing ball core 27 is provided on it with an opening facing downward to expose the sealing ball core 27. The valve seat 12 is provided with a sealing abutment cone surface 121 that matches the sealing ball core 27. The exposed sealing ball core 27 and the valve seat 12 constitute a blockage of the medium flow channel 11. In addition, the sealing ball core 27 moves within the hemispherical sleeve 26. The spherical sealing ball core 27 can rotate to adjust the sealing abutment part when the valve is open, thereby improving the service durability of the sealing ball core 27.

[0048] Furthermore, the valve seat 12 is also provided with a reverse pressure part 122, which is directly opposite the sealing ball core 27. When the valve is closed, the sealing ball core 27 is compressed and will transmit the pressure to the reverse pressure part 122, causing it to deform outward, thereby fitting more tightly to the inner wall of the valve body 1 and enhancing the sealing effect of the valve seat 12 itself. The reverse pressure part 122 can be specifically designed as an upper arched part with a concave groove 123 and a flat part 124 to optimize stress distribution and deformation effect.

[0049] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A bellows gate valve, comprising a valve body (1), a valve stem (2), a bellows sleeve (3), a sealing packing assembly (4), and a drive unit (5), characterized in that: The valve body (1) is provided with a pre-tightening assembly (6), the upper end of which abuts against the sealing packing assembly (4), and the lower end is connected to the bellows sleeve (3); the upper end of the valve stem (2) extends out of the valve body (1) and connects to the drive unit (5), and the lower end is provided with a valve core (21). The valve core (21) includes a valve ball (22) that seals and blocks the medium flow channel (11) with the valve seat (12) in the valve body (1), and a valve plate (23) fixed on the valve stem (2). The upper end of the bellows sleeve (3) is connected to the pre-tightening assembly (6), and the lower end is connected to the valve plate (23); the pre-tightening assembly (6) includes a top pressure plate (61) and a locking rod assembly. The pre-tightening assembly (6) is located inside the bellows sleeve (3). The locking rod assembly (63) includes a rod (62) extending relative to the valve stem (2) and a pre-compression elastic member (64) that elastically pushes the rod (62) to extend. In the normal state of the bellows sleeve (3), the top pressure plate (61) is between the rod (62) and the valve stem (2). After the bellows sleeve (3) ruptures, the medium pressure pushes the top pressure plate (61) to move and release the restriction. The rod (62) extends under the push of the pre-compression elastic member (64) and is used to abut against the stage (25) set on the valve stem (2) to restrict the upward movement of the valve stem (2).

2. The bellows shut-off valve according to claim 1, characterized in that: The upper and lower ends of the corrugated sleeve (3) are respectively provided with welding rings (31) and welding and fixing to the sealing packing assembly (4) and valve plate (23). The valve plate (23) is also provided with an exhaust port (29). When the valve plate (23) compresses the corrugated sleeve (3), the gas in the cavity formed by the outside of the corrugated sleeve (3) and the valve body (1) is discharged.

3. The bellows shut-off valve according to claim 1, characterized in that: The pressure of the inert gas inside the corrugated sleeve (3) in the compressed state is less than the pressure required to push the top pressure plate (61) away from the insert rod (62) and the valve stem (2), and the pressure of the medium transported in the medium flow channel (11) is greater than the pressure required to push the top pressure plate (61) away from the insert rod (62) and the valve stem (2).

4. The bellows shut-off valve according to claim 1, characterized in that: The corrugated sleeve (3) is arranged in an inverted conical structure with a larger upper part and a smaller lower part, and the pleats on the outer surface of the corrugated sleeve (3) extend spirally from top to bottom.

5. The bellows shut-off valve according to claim 1, characterized in that: The sealing packing assembly (4) includes a packing ring (41), a packing sleeve (42), and a packing element (43). The upper end of the top pressure plate (61) abuts against the lower end of the packing element (43). The packing ring (41) is bolted to the packing sleeve (42), and the packing sleeve (42) is bolted to the valve body (1) for sealing.

6. The bellows shut-off valve according to claim 1, characterized in that: The locking rod assembly (63) is provided in several groups, distributed along the outer circumference of the valve stem (2), and installed on the sealing packing assembly (4). The sealing packing assembly (4) is also provided with a movable groove (68) for inserting the rod (62) and a sealing cover (67) for closing the movable groove (68). The sealing cover (67) is used to seal the movable groove (68) and the inner cavity of the valve body (1) by bolts and annular sealing rings.

7. The bellows shut-off valve according to claim 1, characterized in that: The valve ball (22) includes a hemispherical sleeve (26) and a sealing ball core (27). The upper end of the hemispherical sleeve (26) is connected to the valve stem (2), and the lower end is open to accommodate the sealing ball core (27). The sealing ball core (27) is movably disposed relative to the hemispherical sleeve (26). The valve seat (12) includes a sealing abutment cone surface (121) with a size matching the sealing ball core (27).

8. The bellows shut-off valve according to claim 7, characterized in that: The valve seat (12) is also provided with a reverse pressure part (122), which is set directly opposite the sealing ball core (27). It is used to make the valve seat (12) fit the inner wall of the valve body (1) by the squeezing force of the sealing ball core (27) when the sealing ball core (27) is close to the sealing medium flow channel (11) relative to the valve seat (12).

9. The bellows shut-off valve according to claim 8, characterized in that: The reverse pressure section (122) includes an upper arch and a flat surface (124) with a concave groove (123), the concave groove (123) abutting against the sealing ball core (27), and the upper arch is used to deform and disperse the pressure to the side wall of the valve seat (12).

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