A sealing structure for a valve stem of a valve

Abstract

This application discloses a valve stem sealing structure, relating to the field of valve stem sealing technology, including a valve body and a gland. The gland is fastened to the valve body by bolts, and a sealing groove is formed on the upper part of its inner wall, housing an O-ring that fits onto the valve stem. A sealing cavity is formed on the inner wall of the valve body, and multiple sealing modules are provided, including, from top to bottom, a dynamic seal, an elastic sealing assembly, a pair of wedge-shaped sealing packings, and a flexible graphite braided packing. The elastic sealing assembly includes an upper support, a lower support, and a spring disposed between them. Tightening the bolts generates an axial preload, driving the inner and outer protruding lips of the dynamic seal to press tightly against the valve stem and the inner wall of the sealing cavity, respectively, and compressing the sealing packings and packing. This structure, through multiple sealing combinations, significantly improves the reliability, stability, and leakage resistance of the valve stem seal.

Description

Technical Field

[0001] This application relates to the field of valve stem sealing technology, specifically to a valve stem sealing structure. Technical Background In the field of valve technology, the sealing performance of the valve stem is of paramount importance. As one of the key components of a valve, the quality of the valve stem's sealing performance directly affects the overall operating efficiency and safety of the valve. Whether in fluid control applications in industrial production or in the stable operation of plumbing systems in daily life, the sealing performance of the valve stem is a core element in ensuring system stability.

[0002] Chinese Patent (Application No. 202420228585.1) discloses a wedge-type packing seal structure. This structure includes a valve body, a valve stem, a flexible graphite braided packing, several wedge-type sealing packings, a packing gland, and gland bolts. The valve stem is coaxial with the valve body. From the bottom of the valve body upwards, the flexible graphite braided packing, several wedge-type sealing packings, the flexible graphite braided packing, and the packing gland are installed sequentially. The wedge-type sealing packing includes a wedge-type inner ring and a wedge-type outer ring. The radius of the inner sealing ring is smaller than that of the outer wedge-shaped sealing ring. The inner wedge-shaped sealing ring is larger at the top and smaller at the bottom, with a larger outer conical surface and a smaller bottom. The outer wedge-shaped sealing ring is smaller at the top and larger at the bottom, with a larger inner conical surface and a smaller bottom. The two conical surfaces are coupled, and because the generatrix of the conical surfaces slopes from the outside to the inside, a wedge structure is formed. The inner wedge-shaped sealing ring wedges downward, and the resulting force causes the outer wedge-shaped sealing ring to expand outward, pressing against the valve body to achieve a seal with the valve body. The inner wedge-shaped sealing ring compresses inward, pressing against the valve stem to achieve a seal with the valve stem. However, in use, this wedge-shaped packing seal structure still has leakage problems. Utility Model Content

[0003] In view of this, this application provides a valve stem sealing structure to solve the technical problem that leakage still occurs in existing valve stem sealing structures.

[0004] To achieve the above objectives, this application provides the following technical solution: A valve stem sealing structure includes a valve body, a gland, and a valve stem. The valve stem passes through the valve body and the gland. The gland is fastened to the valve body by bolts. The valve body has a sealing cavity coaxial with the valve stem for housing a sealing module. The sealing module includes: A flexible graphite braided packing is placed inside the lowest end of the sealing culvert; A wedge-shaped sealing packing is placed inside the lower end of the sealing cavity and above the flexible graphite braided packing. An elastic sealing assembly is housed in the middle of the sealing cavity and is located above the wedge-shaped sealing packing. A dynamic seal is housed in the upper part of the sealing cavity and abuts against the gland and the resilient sealing assembly.

[0005] Furthermore, the elastic sealing assembly includes an upper support seat, a spring, and a lower support seat. The upper support seat has a through hole coaxial with the valve stem. The upper end of the spring abuts against a first groove on the end face of the upper support seat near the spring. The top of the lower support seat has a second groove opposite to the first groove, and the lower end of the spring abuts against the second groove.

[0006] Furthermore, the lower support base is provided with an outer seal and an inner seal. The outer seal is installed in a first mounting groove opened on the outer side of the bottom of the lower support base; the inner seal is installed in a second mounting groove opened on the inner side of the bottom of the lower support base.

[0007] Furthermore, the inner seal includes a sealing portion and a mounting portion sleeved on the valve stem, the sealing portion being connected to the inner edge of the mounting portion, and the upper end face of the mounting portion being in contact with the first-step bottom wall of the second mounting groove.

[0008] Furthermore, the inner wall of the sealing part is provided with at least two sealing lips, and the plurality of sealing lips are distributed at intervals along the length direction of the valve stem. Furthermore, The external sealing element includes: An overlapping portion, the overlapping portion extending radially and accommodated within the inner groove of the first mounting groove; A sealing body is connected to the outer periphery of the overlapping part and is accommodated in the outer groove of the first mounting groove. The outer wall of the sealing body is provided with multiple sealing protrusions, which abut against the inner wall of the sealing cavity.

[0009] Furthermore, The dynamic seal includes: The annular jacket abuts against the bottom of the pressure cap at its top and against the upper support seat of the elastic sealing assembly at its bottom. An annular groove is provided inside the annular jacket. Multiple elastic plates are installed in an array within the annular groove to radially abut against the two inner walls of the annular groove, such that the outer wall of the annular jacket abuts against the inner wall of the sealing cavity, and the inner wall of the annular jacket abuts against the valve stem.

[0010] Furthermore, both the inner and outer walls of the annular jacket are provided with protruding lips. The protruding lip on the outer wall abuts against the inner wall of the sealing cavity, and the protruding lip on the inner wall abuts against the valve stem.

[0011] Furthermore, the elastic plate is integrally stamped from a V-shaped spring sheet and vertical plates at both ends.

[0012] Furthermore, the vertical plate abuts against the top of the protrusion of the annular groove.

[0013] Compared with the prior art, the beneficial effects of this application are: In this application, the flexible graphite braided packing and the wedge-shaped sealing packing work together to form the first layer of seal; the lower support seat is provided with an outer seal and an inner seal to form the second layer of seal; the dynamic seal is held between the gland and the elastic sealing assembly to form the third layer of seal; the spring in the elastic sealing assembly generates a continuous preload after being compressed, making the seals of each part more reliable, thereby further preventing media leakage. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0015] Figure 1 A schematic diagram of the structure of this application is shown.

[0016] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle.

[0017] Figure 3 This is a schematic diagram of the gland structure.

[0018] Figure 4 Showing Figure 1 Enlarged view of the connection relationship between the central sealing mold, sealing cavity, valve stem, and gland.

[0019] Figure 5 This is a cross-sectional view of a dynamic seal.

[0020] Figure 6 This is a schematic diagram showing the connection relationship between the lower support base and the outer seal, inner seal, and valve stem.

[0021] Figure 7 This is a schematic diagram showing the connection relationship between the lower support, the inner seal, and the valve stem.

[0022] Explanation of reference numerals in the attached figures: 1-Valve body; 11-Sealing cavity; 2-Gland; 21-Sealing groove; 3-Valve stem; 4-O-ring seal; 5-Fixing pressure plate; 6-Dynamic seal; 61-Annular jacket; 611-Raised lip; 613-Annular groove; 6131-Boss; 62-Elastic plate; 621-Vertical plate; 7-Upper support seat; 71-First groove; 8-Spring; 9-Lower support seat; 91-Second groove; 92-First mounting groove; 921-Inner groove; 922-Outer groove; 93-Second mounting groove; 94-Outer seal; 941-Overlap; 942-Sealing body; 943-Sealing protrusion; 95-Inner seal; 951-Mounting part; 952-Sealing part; 953-Sealing lip; 10-Wedge seal packing; 20-Flexible graphite braided packing. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] refer to Figures 1 to 7 ,like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a valve stem sealing structure, including a valve body 1 and a gland 2. A valve stem 3 passes through the valve body 1 and the gland 2, and the gland 2 is fastened to the valve body 1 by bolts. A sealing groove 21, coaxial with the valve stem 3, is formed on the upper part of the inner wall of the gland 2. An O-ring 4 is installed in the sealing groove 21, and the O-ring 4 is fitted around the outer circumference of the valve stem 3, undergoing radial compression deformation to form a preliminary seal on the valve stem 3.

[0025] like Figure 1 and Figure 4 As shown, the inner wall of the valve body 1 has a sealing cavity 11 coaxial with the valve stem 3, and the sealing module is disposed inside the sealing cavity 11. The sealing module adopts a layered arrangement, from top to bottom: dynamic seal 6, elastic sealing assembly, a pair of wedge-type sealing packings 10, and flexible graphite braided packing 20. The elastic sealing assembly includes an upper support seat 7 and a lower support seat 9. The inner wall of the upper support seat 7 has a through hole coaxial with the valve stem 3. The end face of the upper support seat 7 near the spring 8 has a first groove 71. The top of the lower support seat 9 has a second groove 91 opposite to the first groove 71. The spring 8 is sleeved on the valve stem 3 and is placed between the upper support seat 7 and the lower support seat 9. Its upper end abuts against the first groove 71, and its lower end abuts against the second groove 91.

[0026] When the bolts are tightened, the gland 2 applies axial pressure to the upper support seat 7, thereby compressing the spring 8. The compressed spring 8 generates a continuous axial preload, which is transmitted to the annular jacket 61, causing the protruding lips 611 on its inner and outer walls to tightly abut against the valve stem 3 and the inner wall of the sealing cavity 11, respectively, achieving further sealing. Simultaneously, this preload also causes multiple sealing protrusions 943 on the outer wall of the sealing body 942 to press tightly against the inner wall of the sealing cavity 11, and multiple sealing lips 953 to tightly abut against the valve stem 3, further enhancing the sealing effect. Furthermore, the preload also makes the flexible graphite braided packing 20 and the wedge-shaped sealing packing 10 more reliably seal the sealing cavity 11, effectively preventing leakage and greatly improving the valve's sealing reliability and stability.

[0027] The pair of wedge-shaped sealing packings 10 have the same structure as the wedge-shaped sealing packings disclosed in patent 202420228585.1, including a wedge-shaped inner sealing ring and a wedge-shaped outer sealing ring. The wedge-shaped inner sealing ring is wider at the top and narrower at the bottom, with its outer conical surface being wider at the top and narrower at the bottom. The wedge-shaped outer sealing ring is narrower at the top and wider at the bottom, with its inner conical surface being wider at the top and narrower at the bottom. The two conical surfaces mesh to form a wedge structure. When the wedge-shaped inner sealing ring wedges downward, the resulting force causes the wedge-shaped outer sealing ring to expand outward and press tightly against the sealing cap 11 to achieve a seal.

[0028] The flexible graphite braided packing 20 is disposed at the bottom of the sealing duct 11. Its structure is the same as that of the flexible graphite braided packing in patent 202420228585.1, and the material is flexible graphite.

[0029] The O-ring 4 is made of rubber, which has good elasticity, flexibility, and corrosion resistance, and can maintain stable sealing performance under different temperature and pressure conditions. After installation, it can better fit with the valve stem 3 to form a reliable seal.

[0030] Further, refer to Figure 4 and Figure 6 The lower support 9 also includes an outer seal 94 and an inner seal 95, both made of rubber. The outer seal 94 is installed in a first mounting groove 92 on the outer side of the bottom of the lower support 9, and the outer seal 94 is pressed against the side wall of the sealing cavity 11 to achieve a seal on the sealing cavity 11. The inner seal 95 is installed in a second mounting groove 93 on the inner side of the bottom of the lower support 9, and the inner seal 95 includes a sealing part 952 sleeved on the valve stem 3 and a mounting part 951. The upper end face of the mounting part 951 is in contact with the first bottom wall of the second mounting groove 93.

[0031] like Figure 5 and Figure 6 As shown, the sealing part 952 and the mounting part 951 are integrally formed, which enhances the overall strength and structural stability of the inner seal 95, enabling it to better withstand the pressure of the medium and external forces.

[0032] To further optimize the sealing structure, a fixing plate 5 is provided on the lower end face of the mounting part 951. The fixing plate 5 is fixedly installed in the second mounting groove 93 by screws. The fixing plate 5 is made of stainless steel. After tightening the screws, the fixing plate 5 presses the mounting part 951 against the first bottom wall of the second mounting groove 93, so that a reliable seal is formed between the mounting part 951 and the lower support seat 9.

[0033] In the embodiments of this application, such as Figure 5 As shown, the dynamic seal 6 consists of an annular jacket 61 and multiple elastic plates 62. The top of the annular jacket 61 abuts against the bottom of the gland 2, and an annular groove 613 is formed on the lower surface of the annular jacket 61 to accommodate the elastic plates 62. The multiple elastic plates 62 are arranged in an array within the annular groove 613, which can uniformly apply radial bearing force, so that the protruding lips 611 on the inner and outer walls of the annular jacket 61 tightly abut against the valve stem 3 and the inner wall of the sealing cavity 11, respectively, ensuring the stability and reliability of the seal and effectively preventing media leakage.

[0034] refer to Figure 7 The inner wall of the sealing part 952 is provided with at least two sealing lips 953. Each sealing lip 953 is distributed at intervals along the length of the valve stem 3. The multiple sealing lips 953 form multiple sealing defenses, which increases leakage resistance and improves sealing effect.

[0035] refer to Figure 6 The outer seal 94 includes an overlapping portion 941 and a sealing body portion 942. The overlapping portion 941 extends radially and is accommodated within the inner groove 921 of the first mounting groove 92. The sealing body portion 942 is connected to the outer periphery of the overlapping portion 941 and is accommodated within the outer groove 922 of the first mounting groove 92. The outer wall of the sealing body portion 942 is provided with multiple sealing protrusions 943. The cross-section of the sealing protrusions 943 is trapezoidal. The multiple sealing protrusions 943 can form multiple sealing contact surfaces with the inner wall of the sealing cavity 11. The trapezoidal cross-section structure allows the sealing protrusions 943 to generate high contact pressure when in contact with the sealing cavity 11, while also having good elastic deformation ability to ensure sealing effect.

[0036] Furthermore, the elastic plate 62 is integrally stamped from a V-shaped spring sheet and vertical plates 621 at both ends, with the V-shaped opening parallel to the axis of the valve stem 3. The vertical plates 621 abut against the top of the boss portion 6131, making the connection between the elastic plate 62 and the annular sleeve 61 firm, able to withstand greater external forces, and preventing it from falling off or loosening during operation.

[0037] Specifically, the material of the annular jacket 61 is rubber.

[0038] As an alternative implementation, the ring-shaped jacket 61, the inner seal 95, and the outer seal 94 can also be made of polytetrafluoroethylene (PTFE). PTFE has good corrosion resistance and non-stick properties, can maintain stable sealing performance in a variety of corrosive media, and ensures that the sealing surface remains clean for a long time.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A valve stem sealing structure for a valve, comprising a valve body (1) and a gland (2), wherein a valve stem (3) passes through the valve body (1) and the gland (2), the gland (2) being fastened to the valve body (1) by bolts, and the valve body (1) having a sealing cavity (11) coaxial with the valve stem (3) for placing a sealing module, characterized in that, The sealing module includes: A flexible graphite braided packing (20) is placed inside the lowest end of the sealing duct (11); Wedge-shaped sealing packing (10) is placed inside the lower end of the sealing culvert (11) and above the flexible graphite braided packing (20); The resilient sealing assembly is housed in the middle of the sealing cavity (11) and is located above the wedge-shaped sealing packing (10); A dynamic seal (6) is housed on the upper part of the sealing cavity (11) and abuts against the gland (2) and the elastic sealing assembly.

2. The valve stem sealing structure according to claim 1, characterized in that, The elastic sealing assembly includes an upper support (7), a spring (8), and a lower support (9). The upper support (7) has a through hole coaxial with the valve stem (3). The upper end of the spring (8) abuts against a first groove (71) on the end face of the upper support (7) near the spring (8). The lower support (9) has a second groove (91) on its top that is opposite to the first groove (71). The lower end of the spring (8) abuts against the second groove (91).

3. The valve stem sealing structure according to claim 2, characterized in that, The lower support (9) is provided with an outer seal (94) and an inner seal (95). The outer seal (94) is installed in the first mounting groove (92) opened on the outer side of the bottom of the lower support (9); the inner seal (95) is installed in the second mounting groove (93) opened on the inner side of the bottom of the lower support (9).

4. The valve stem sealing structure according to claim 3, characterized in that, The inner seal (95) includes a sealing part (952) sleeved on the valve stem (3) and a mounting part (951). The sealing part (952) is connected to the inner edge of the mounting part (951), and the upper end face of the mounting part (951) is in contact with the first bottom wall of the second mounting groove (93).

5. The valve stem sealing structure according to claim 4, characterized in that, The inner wall of the sealing part (952) is provided with at least two sealing lips (953), and the plurality of sealing lips (953) are distributed at intervals along the length direction of the valve stem (3).

6. The valve stem sealing structure according to claim 3, characterized in that, The outer seal (94) includes: An overlap (941) extends radially and is received within the inner groove (921) of the first mounting groove (92); A sealing body (942) is connected to the outer periphery of the overlapping part (941) and is accommodated in the outer groove (922) of the first mounting groove (92). The outer wall of the sealing body (942) is provided with multiple sealing protrusions (943), and the sealing protrusions (943) abut against the inner wall of the sealing cavity (11).

7. The valve stem sealing structure according to claim 1, characterized in that, The dynamic seal (6) includes: The annular sleeve (61) abuts against the bottom of the pressure cap (2) at the top and against the upper support seat (7) of the elastic sealing assembly at the bottom. An annular groove (613) is provided inside the annular sleeve (61). Multiple elastic plates (62) are arranged in an array within the annular groove (613) to radially abut against the two inner walls of the annular groove (613), such that the outer wall of the annular jacket (61) abuts against the inner wall of the sealing duct (11), and the inner wall of the annular jacket (61) abuts against the valve stem (3).

8. The valve stem sealing structure according to claim 7, characterized in that, The inner and outer walls of the annular jacket (61) are provided with protruding lips (611). The protruding lip (611) on the outer wall abuts against the inner wall of the sealing duct (11), and the protruding lip (611) on the inner wall abuts against the valve stem (3).

9. The valve stem sealing structure according to claim 7, characterized in that, The elastic plate (62) is integrally stamped from a V-shaped spring sheet and vertical plates (621) at both ends.

10. The valve stem sealing structure according to claim 9, characterized in that, The vertical plate (621) abuts vertically against the top of the boss (6131) of the annular groove (613).

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