Multiple sealing structure of ball valve stem

Abstract

This utility model provides a multi-seal structure for a ball valve stem, relating to industrial, construction, and chemical technologies. It includes a valve body with a packing gland at its top. A sealing support ring is located at the bottom of the packing gland within the valve body, and a lip seal ring is installed within the sealing support ring. The sealing support ring structure uses a lip seal ring to seal the valve body and valve stem body. During installation, the open lip edge of the lip seal ring faces the working pressure side; the higher the working pressure, the wider the lip edge opens, tightly fitting against the outer diameter of the valve stem body and the inner bore of the valve body to ensure a seal. The packing gland is bolted to the threaded hole on the valve body to secure the sealing support ring. Simultaneously, a graphite fireproof gasket is installed between the sealing support ring and the packing gland to ensure that even in the event of a fire, when the soft lip seal ring fails, the valve stem body remains sealed, preventing leakage of the medium from the pipeline.

Description

Technical Field

[0001] This utility model relates to the technical fields of industry, construction, and chemical industry, and in particular to a multi-seal structure for a ball valve stem. Background Technology

[0002] Ball valves are relatively simple in structure, easy to install and maintain, and do not require specialized technicians. They are widely used in fluid control systems for various liquid or powder / particle media, such as water, oil, gas, and powders. They are widely used in industrial, construction, and chemical industries.

[0003] Currently, there are two main sealing structures for control ball valves: one is a packing combination seal, where bolts are used to tighten the packing gland to compress the packing and form a seal; the other is an O-ring seal. The drawback of existing products on the market is that while the packing combination seal allows for online maintenance, its working principle relies on the packing gland's clamping force to ensure the packing's deformation for a seal. In actual operating conditions with vibration, the fasteners on the packing gland can loosen due to vibration, causing the packing to lose its clamping force and leading to leakage at the valve stem. This problem is particularly prominent in small-diameter process pipelines. The O-ring seal involves machining a sealing groove on the valve stem's outer diameter or the stuffing box's inner hole. When using axial sealing, the O-ring's deformation achieves a sealing effect. However, this structure has the potential for leakage when the medium pressure suddenly increases, as the seal deformation can be instantaneously ruptured. Furthermore, with O-ring seals, when leakage occurs at the valve stem, due to the structural design, the valve stem and stuffing box must be returned to the factory for disassembly and replacement of the seals, making online maintenance and seal replacement impossible. Utility Model Content

[0004] The purpose of this invention is to solve the problem in existing technologies where the sealing is achieved by the compression force of the packing gland to ensure the deformation of the packing. However, in actual operating conditions with vibration, the fasteners on the packing gland can loosen due to vibration, causing the packing compression to disappear and leading to leakage at the valve stem. This problem is particularly prominent in small-diameter process pipelines. O-ring seals involve machining a sealing groove on the outer diameter of the valve stem or the inner hole of the stuffing box. When using axial sealing, the deformation of the O-ring achieves the sealing effect. However, this structure may experience instantaneous rupture of the sealing ring under sudden increases in medium pressure, leading to leakage. Furthermore, with O-ring seal structures, when leakage occurs at the valve stem, the valve stem and stuffing box must be returned to the factory for disassembly and replacement of the seals due to structural design limitations, making online maintenance and seal replacement impossible. Therefore, this invention proposes a multi-seal structure for the ball valve stem.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a multi-seal structure for a ball valve stem, comprising a valve body, a packing gland installed at the top of the valve body, a sealing support ring located at the bottom of the packing gland inside the valve body, a lip seal ring located inside the sealing support ring, a valve stem body located inside the packing gland, a ball core matching the valve stem body located inside the valve body, the packing gland being installed to the valve body by bolts, and an elastic washer located at the top of the packing gland outside the bolts.

[0006] Preferably, a valve cover is installed at one end of the valve body, and the valve cover and the valve body together have a spherical cavity that matches the ball core.

[0007] Preferably, the outer wall of the valve cover and the valve body opposite to each other is fixed with a flange.

[0008] Preferably, a graphite fireproof gasket is fixed to the top of the sealing support ring.

[0009] Preferably, the graphite fireproof gasket, lip seal, and sealing support ring are tightly fitted to the outer diameter of the valve stem body.

[0010] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0011] In this invention, a sealing support ring structure is adopted. A lip seal is used to seal the connection between the sealing support ring and the valve body and valve stem body. During installation, the open lip edge of the lip seal faces the working pressure side; the higher the working pressure, the wider the lip edge opens, tightly fitting against the outer diameter of the valve stem body and the inner bore of the valve body to ensure a seal. The packing gland is bolted to the threaded hole on the valve body to secure the position of the sealing support ring. Simultaneously, a graphite fireproof gasket is installed between the sealing support ring and the packing gland to ensure that even in the event of a fire, if the soft lip seal fails, the valve stem body remains sealed, preventing leakage of the medium from the pipeline. Furthermore, an elastic washer assembly is installed between the bolts and the packing gland to eliminate the influence of bolt preload on valve operation. Even if significant temperature changes in the pipeline cause minor bolt length variations, the deformation of the elastic washer effectively eliminates this effect. Attached Figure Description

[0012] Figure 1 A cross-sectional view of a multi-seal structure for a ball valve stem is provided for this utility model;

[0013] Figure 2 This utility model provides a schematic diagram of the external structure of the packing gland for a ball valve stem with multiple sealing structure;

[0014] Figure 3 A sectional view of a lip seal ring for a ball valve stem multi-seal structure is provided for this utility model.

[0015] Legend: 1. Valve body; 2. Valve cover; 3. Flange; 4. Ball core; 5. Packing gland; 6. Valve stem body; 7. Lip seal; 8. Graphite fireproof gasket; 9. Bolt; 10. Elastic washer; 11. Sealing support ring. Detailed Implementation

[0016] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0018] Example 1, as Figure 1-3 As shown, this utility model provides a multi-seal structure for a ball valve stem, including a valve body 1, a packing gland 5 installed at the top of the valve body 1, a sealing support ring 11 located at the bottom of the packing gland 5 inside the valve body 1, a lip seal ring 7 located inside the sealing support ring 11, a valve stem body 6 located inside the packing gland 5, a ball core 4 matching the valve stem body 6 located inside the valve body 1, the packing gland 5 being installed to the valve body 1 by bolts 9, and an elastic washer 10 located at the top of the packing gland 5 outside the bolts 9.

[0019] The overall effect of Embodiment 1 is as follows: A sealing support ring 11 structure is used, and a lip seal 7 is used to seal the connection between the sealing support ring 11 and the valve body 1 and the valve stem body 6. During installation, the open lip edge of the lip seal 7 faces the working pressure side; the higher the working pressure, the wider the lip edge opens, tightly fitting against the outer diameter of the valve stem body 6 and the inner hole of the valve body 1 to ensure a seal. The packing gland 5 is tightened to the threaded hole on the valve body 1 via bolts 9, ensuring the position of the sealing support ring 11. Simultaneously, an elastic washer 10 is assembled between the bolts 9 and the packing gland 5 to eliminate the influence of the bolt preload on valve operation. Even if the bolts 9 undergo slight length changes due to large temperature variations in the medium in the pipeline, the deformation of the elastic washer 10 can effectively eliminate this effect.

[0020] Example 2, as Figure 1-3 As shown, a valve cover 2 is installed at one end of the valve body 1. The valve cover 2 and the valve body 1 have a spherical cavity that matches the ball core 4. A flange 3 is fixed to the outer wall of the valve cover 2 and the valve body 1 opposite to each other. A graphite fireproof gasket 8 is fixed to the top of the sealing support ring 11. The graphite fireproof gasket 8, the lip seal ring 7 and the sealing support ring 11 are in close contact with the outer diameter of the valve stem body 6.

[0021] The effect achieved by the entire embodiment 2 is that by installing a graphite fireproof gasket 8 between the sealing support ring 11 and the packing gland 5, the valve stem body 6 is still sealed when the soft lip seal ring 7 fails in the event of a valve fire, and the medium in the pipeline will not leak outward.

[0022] Working Principle: This device employs a sealing support ring 11 structure. A lip seal 7 is used to seal the connection between the sealing support ring 11 and the valve body 1 and valve stem body 6. During installation, the open lip edge of the lip seal 7 faces the working pressure side; the higher the working pressure, the wider the lip edge opens, tightly adhering to the outer diameter of the valve stem body 6 and the inner hole of the valve body 1, ensuring a seal. The packing gland 5 is secured to the valve body 1 by bolts 9 engaging with threaded holes, ensuring the position of the sealing support ring 11. Simultaneously, a graphite fireproof gasket 8 is installed between the sealing support ring 11 and the packing gland 5 to ensure that even in the event of a fire, if the soft lip seal 7 fails, the valve stem body 6 remains sealed, preventing leakage of the medium from the pipeline. Furthermore, an elastic washer 10 is assembled between the bolts 9 and the packing gland 5 to eliminate the influence of the bolt preload on valve operation. Even if significant temperature changes in the pipeline cause minor length changes in the bolts 9, the deformation of the elastic washer 10 effectively eliminates this effect.

[0023] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A multi-seal structure for a ball valve stem, comprising a valve body (1), characterized in that: A packing gland (5) is installed at the top of the valve body (1). A sealing support ring (11) is provided at the bottom of the packing gland (5) inside the valve body (1). A lip seal (7) is provided inside the sealing support ring (11). A valve stem body (6) is provided inside the packing gland (5). A ball core (4) matching the valve stem body (6) is provided inside the valve body (1). The packing gland (5) is installed with the valve body (1) by bolts (9). An elastic washer (10) is provided at the top of the packing gland (5) outside the bolts (9).

2. The multi-seal structure for a ball valve stem according to claim 1, characterized in that: A valve cover (2) is installed at one end of the valve body (1), and a spherical cavity matching the ball core (4) is opened in both the valve cover (2) and the valve body (1).

3. The multi-seal structure for a ball valve stem according to claim 2, characterized in that: The outer wall of the valve cover (2) opposite to the valve body (1) is fixed with a flange (3).

4. The multi-seal structure for a ball valve stem according to claim 1, characterized in that: A graphite fireproof gasket (8) is fixed to the top of the sealing support ring (11).

5. The multi-seal structure for a ball valve stem according to claim 4, characterized in that: The graphite fireproof gasket (8), lip seal (7) and sealing support ring (11) are tightly attached to the outer diameter of the valve stem body (6).

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