Floating ball valve with thrust system

Abstract

The utility model discloses a floating ball valve with thrust system, including valve body, valve stem, ball and the combination packing of setting between valve stem and valve body, the outer surface of valve stem is provided with valve stem shoulder, and the upper portion of valve stem shoulder is provided with thrust system, and the thrust system includes the upper sealing ring of valve stem, metal compression ring and the lower sealing ring of valve stem from top to bottom and sets gradually, metal compression ring is clamped between the upper sealing ring of valve stem and the lower sealing ring of valve stem, and the lower surface of the lower sealing ring of valve stem is close to the upper surface of valve stem shoulder, and the upper surface of the upper sealing ring of valve stem is close to the internal step surface of valve body. The utility model overcomes the insufficient of prior art, utilizes medium pressure to realize self -adaptation sealing, forms the second seal of being located below packing, and simultaneously through multiple parallel plane dispersion axial load, constitutes the thrust structure of low friction torque. Effectively solved the problem that the valve stem place of traditional floating ball valve is easy to leak, and the operation torque is big, and is easy to jam.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, specifically to a floating ball valve with a thrust system. Background Technology

[0002] Floating ball valves, as a key fluid control component, are widely used in pipeline systems under harsh conditions in industries such as petroleum, chemical, natural gas, energy, and long-distance pipelines due to their relatively simple structure, good sealing performance, and rapid opening and closing. Their core working principle is to use the pressure of the medium within the valve chamber to push the ball towards the downstream valve seat, thereby forming a seal. However, this pressure simultaneously acts on the bottom of the valve stem connected to the ball, generating an axial force that causes the valve stem to move outwards from the valve body.

[0003] To prevent the valve stem from accidentally detaching from the valve body under medium pressure, the most common method in existing technology is to machine a shoulder structure on the valve stem. When the valve stem is subjected to an upward thrust, the valve stem shoulder contacts the corresponding bearing surface inside the valve body, forming a mechanical limit. Although this method is simple and effective, the valve stem needs to rotate 90 degrees during the valve opening and closing process. Due to the huge axial pressure (originating from the medium pressure) between the valve stem shoulder and the bearing surface of the valve body, a large sliding friction resistance is generated when they rotate relative to each other. This directly leads to an increase in valve operating torque, which not only requires a more powerful actuator, increasing equipment costs, but also makes manual operation more laborious, and may even cause the valve stem to break due to excessive torque. Furthermore, the direct, high-speed friction between the valve stem shoulder and the metal surface of the valve body easily leads to wear of the contact surface. After long-term operation, the gaps caused by wear may affect the axial positioning accuracy of the valve stem, and thus affect the sealing alignment of the ball and valve seat. In addition, the valve stem shaft seal of traditional floating ball valves mainly relies on the combined packing in the stuffing box for sealing. Packing wear is the main cause of external leakage of the valve. In the existing structure, the friction at the valve stem shoulder exacerbates valve stem vibration and fretting, accelerates the wear and failure of the upper packing, and shortens the service life of the sealing system. When the transported medium contains solid particles (such as slurry, coal chemical raw materials, etc.), these particles can easily intrude into the narrow friction pair gap between the valve stem shoulder and the valve body. Hard particles act as abrasives, accelerating wear; while particles with a certain degree of viscosity or larger size may cause "pad damage" or direct jamming, preventing the valve stem from rotating normally, thus leading to valve opening and closing failures. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a floating ball valve with a thrust system, overcoming these deficiencies. It utilizes medium pressure to achieve adaptive sealing, forming a second seal below the packing. Simultaneously, multiple parallel planes disperse the axial load, creating a low-friction torque thrust structure. This effectively solves the problems of easy leakage at the valve stem, high operating torque, and easy jamming in traditional floating ball valves.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A floating ball valve with a thrust-resistant system includes a valve body, a valve stem, a ball, and a combined packing material disposed in a stuffing box between the valve stem and the valve body. The outer surface of the valve stem has a valve stem shoulder, and a thrust-resistant system is disposed above the valve stem shoulder. The thrust-resistant system includes an upper valve stem sealing ring, a metal pressure ring, and a lower valve stem sealing ring arranged sequentially from top to bottom. Both the upper and lower valve stem sealing rings are made of elastic material, while the metal pressure ring is made of rigid material. The metal pressure ring is clamped between the upper and lower valve stem sealing rings. The lower surface of the lower valve stem sealing ring is in close contact with the upper surface of the valve stem shoulder, and the upper surface of the upper valve stem sealing ring is in close contact with the internal stepped surface of the valve body.

[0007] Preferably, the upper surface of the metal pressure ring has a circumferentially oriented inclined groove; the lower surface of the valve stem sealing ring has an inclined convex ring that mates with the inclined groove; the inclined convex ring is fitted into the inclined groove.

[0008] Preferably, the mating inclined surfaces of the inclined groove and the inclined convex ring are located on the outer side wall of the inclined groove and the outer side wall of the inclined convex ring, respectively.

[0009] Preferably, the thrust system is located below the combined packing and together with the combined packing in the axial position of the valve stem, forms two independent sealing structures.

[0010] Preferably, the elastic material of the upper sealing ring and the lower sealing ring of the valve stem is one of polytetrafluoroethylene, reinforced polytetrafluoroethylene, or flexible graphite.

[0011] Preferably, the metal pressure ring is made of stainless steel, alloy steel, or copper alloy.

[0012] This invention provides a floating ball valve with a thrust system. It offers the following advantages: a second pressure-adaptive seal, consisting of a thrust system, is added below the combined packing. The two seals are completely independent in structure, principle, and force source, forming a double safety guarantee. Even if the upper combined packing wears down due to long-term use, the lower thrust seal can still effectively block the medium, greatly extending the valve's leak-free operation cycle. The sealing force of the thrust system is directly and proportionally derived from the valve cavity medium pressure. The higher the pressure, the automatically enhanced sealing specific pressure achieves a dynamic optimal match between sealing performance and operating pressure. This mechanism is particularly suitable for high-pressure and frequently fluctuating pressure applications, solving the problems of insufficient sealing specific pressure under high pressure and excessive friction caused by pre-tightening force under low pressure in traditional structures. Furthermore, the axial concentrated load is dispersed through multiple parallel pressure-bearing planes, reducing the pressure on each contact surface and further reducing frictional resistance. The reduced torque allows for the use of a smaller power actuator, lowering the initial equipment cost; for manual operation, it greatly reduces the operational intensity and avoids the risk of valve stem breakage due to excessive torque. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in this utility model or the prior art, the accompanying drawings used in the description of the prior art will be briefly introduced below.

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0016] Explanation of the labels in the diagram:

[0017] 1. Valve body; 2. Valve stem; 3. Ball; 4. Combined packing; 5. Valve stem shoulder; 6. Upper valve stem sealing ring; 7. Metal pressure ring; 8. Lower valve stem sealing ring; 9. Inclined groove; 10. Inclined convex ring. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0019] Example 1, as Figures 1 to 2As shown, a floating ball valve with a thrust-resistant system includes a valve body 1, a valve stem 2, a ball 3, and a combined packing 4 disposed in a stuffing box between the valve stem 2 and the valve body 1. A valve stem shoulder 5 is provided on the outer surface of the valve stem 2, and a thrust-resistant system is provided above the valve stem shoulder 5. The thrust-resistant system includes an upper valve stem sealing ring 6, a metal pressure ring 7, and a lower valve stem sealing ring 8 arranged sequentially from top to bottom. The upper valve stem sealing ring 6 and the lower valve stem sealing ring 8 are both made of elastic material, while the metal pressure ring 7 is made of rigid material. The metal pressure ring 7 is clamped between the upper valve stem sealing ring 6 and the lower valve stem sealing ring 8. The lower surface of the lower valve stem sealing ring 8 is in close contact with the upper surface of the valve stem shoulder 5, and the upper surface of the upper valve stem sealing ring 6 is in close contact with the internal stepped surface of the valve body 1.

[0020] Working principle:

[0021] When the valve is in the closed or stably open state, the pressure of the medium in the valve cavity acts on the ball 3 and is transmitted through the ball to the valve stem 2, which is fixedly connected to it, generating an upward axial thrust. This thrust pushes the valve stem 2 and the valve stem lower sealing ring 8 in contact with it to move upward.

[0022] At this point, firstly, the lower valve stem sealing ring 8 is tightly fitted to the upper surface of the valve stem shoulder 5, and the elastic deformation of the lower valve stem sealing ring 8 ensures that it maintains good sealing performance even under axial thrust. Secondly, the axial thrust is transmitted to the metal pressure ring 7 above the lower valve stem sealing ring 8. The metal pressure ring 7, acting as a rigid carrier, evenly transmits the thrust upward to the upper valve stem sealing ring 6. Under the action of thrust, the upper surface of the upper valve stem sealing ring 6 is pressed against the pre-set stepped surface inside the valve body 1. Since the upper valve stem sealing ring 6 is made of elastic material, it undergoes slight deformation under pressure, fully filling the microscopic unevenness of the stepped surface inside the valve body 1, thereby achieving radial sealing between the thrust system and the valve body. Simultaneously, the tight fit between the lower valve stem sealing ring 8 and the upper surface of the valve stem shoulder 5 achieves axial sealing between the thrust system and the valve stem. This results in a reliable seal between the upper valve stem sealing ring 6 and the stepped surface inside the valve body, reducing the potential for external leakage due to packing wear.

[0023] Meanwhile, since the clamping force (i.e., sealing pressure) applied to the thrust system is directly derived from and proportional to the medium pressure in the valve cavity, the axial thrust increases when the medium pressure increases, which in turn automatically increases the sealing pressure, and vice versa. This "pressure adaptive" characteristic ensures that the valve automatically achieves optimal sealing performance across a wide range of operating conditions, from low to high pressure. This avoids leakage risks at low pressure and prevents unnecessary friction caused by excessive preload at low pressure.

[0024] Furthermore, in this embodiment, the upper surface of the valve stem shoulder 5, the upper and lower surfaces of the lower valve stem sealing ring 8, the upper and lower surfaces of the metal pressure ring 7, the upper and lower surfaces of the upper valve stem sealing ring 6, and the internal stepped surface of the valve body 1 together constitute multiple parallel pressure-bearing planes. Therefore, the enormous axial thrust generated by the medium pressure is sequentially distributed across these multiple parallel contact surfaces, rather than being concentrated at a single point between the valve stem shoulder and the valve body metal. Specifically, the load transmission path is: valve stem shoulder 5 → lower valve stem sealing ring 8 → metal pressure ring 7 → upper valve stem sealing ring 6 → valve body 1. This dispersion effect greatly reduces the pressure per unit area on each contact surface.

[0025] Furthermore, during the valve opening and closing process, the valve stem 2 rotates. At this time, the main relative motion occurs at two interfaces: a) between the rotating valve stem shoulder 5 and the stationary lower valve stem sealing ring 8; b) between the stationary upper valve stem sealing ring 6 and the stepped surface of the valve body 1. At both interfaces, the rotating side contacts a self-lubricating elastic sealing ring material. The coefficient of friction between the elastic material and the metal is much lower than the metal / metal dry friction coefficient, thus significantly reducing the operating torque required for valve stem rotation. The metal pressure ring 7, acting as a rigid spacer, ensures uniform force distribution and stable position of the upper and lower sealing rings, maintaining the parallel relationship of each bearing surface.

[0026] In Example 2, as a further preferred embodiment of Example 1, a circumferentially inclined groove 9 is formed on the upper surface of the metal pressure ring 7; a circumferentially inclined convex ring 10 that mates with the inclined groove is provided on the lower surface of the valve stem sealing ring 6; the inclined convex ring 10 is fitted into the inclined groove 9. Through the engagement of the inclined convex ring 10 and the inclined groove 9, a stable mechanical interlocking connection is formed between the valve stem sealing ring 6 and the metal pressure ring 7. This effectively resists the relative rotation or lateral movement between components that may be caused by the circumferential force transmitted by the rotation of the valve stem 2 or by working vibration during the valve opening and closing process. This ensures that the valve stem sealing ring 6, the metal pressure ring 7, and the valve stem lower sealing ring 8 always maintain precise coaxiality and relative positional relationship after assembly and during long-term operation. This, in turn, ensures that the axial load can be transmitted evenly and stably along the designed path, avoiding local stress concentration or uneven sealing caused by component misalignment. In addition, when the pressure of the medium in the valve cavity pushes the entire thrust system upward, the axial force acts on the metal pressure ring 7. Because the contact surface between the inclined groove 9 and the inclined convex ring 10 is inclined, the axial force can be decomposed into two components on the contact inclined surface: a normal force perpendicular to the inclined surface and a radial component along the inward direction of the inclined surface (pointing towards the valve stem axis). This inward radial component will cause a slight inward contraction or tightening tendency in the region of the inclined convex ring 10 of the valve stem sealing ring 6. This tendency directly translates into a tighter radial contact pressure between the outer cylindrical surface of the valve stem sealing ring 6 and the inner wall of the valve body step 1. This achieves an active conversion and enhancement from axial pressure to radial sealing pressure, thereby effectively improving the reliability of the seal between the valve stem sealing ring and the valve body and its ability to follow pressure fluctuations.

[0027] In Example 3, as a further preferred embodiment of Example 2, the mating inclined surfaces of the inclined groove 9 and the inclined convex ring 10 are located on the outer walls of the inclined groove 9 and the outer walls of the inclined convex ring 10, respectively. Under the action of the medium pressure in the valve cavity, the entire thrust system is subjected to an upward axial force through the metal pressure ring 7 acting on the inclined convex ring 10 of the sealing ring 6 on the valve stem. Since the contact inclined surface is located on the outside, the force decomposition will generate a significant radial component force pointing towards the center of the valve stem axis. This radial component force causes the sealing ring on the valve stem to produce an inward contraction pre-tightening effect, thereby effectively increasing the radial contact pressure between the outer cylindrical surface of the sealing ring 6 on the valve stem and the stepped surface of the inner wall of the valve body 1. Furthermore, the greater the medium pressure, the greater the axial force, and the greater the inward radial component force generated, thus automatically increasing the sealing specific pressure and exhibiting pressure self-tightening characteristics. This fundamentally solves the problem of insufficient sealing specific pressure that may occur in traditional structures under high pressure.

[0028] In Example 4, as a further preferred embodiment of Example 1, the thrust system is located below the combined packing 4 and forms two independent sealing structures with the combined packing 4 in the axial position of the valve stem 2. The upper combined packing 4 serves as the first (main) seal, typically applying initial pre-tightening force through the packing gland, and is an active compression seal. The lower thrust system (through the upper and lower sealing rings of the valve stem) serves as the second seal, its sealing force directly derived from the medium pressure, and is a pressure-adaptive seal. The two seals are completely independent in principle, force source, and structure. During long-term valve operation, the combined packing 4 may gradually fail due to wear, aging, or temperature cycling. In traditional valves, this would directly lead to external leakage of the medium. At this time, the second thrust seal system can still effectively function, continuing to prevent medium leakage. Thus, even in the event of combined packing failure or partial degradation, self-tightening sealing can still be achieved by relying on medium pressure, effectively preventing leakage. This provides valuable safety margins and time windows for preventative maintenance and emergency response, greatly reducing the risk of safety accidents, environmental pollution, or production interruptions caused by sudden leaks. The combined packing 4 is located on the outermost side, facilitating adjustment and compensation via an external gland. It primarily handles initial sealing, daily micro-leakage control, and low-pressure conditions. Its maintenance and replacement are relatively convenient. The thrust system seal is located on the inner side, directly facing the valve cavity medium. It is not only an axial thrust component but also achieves self-adaptive sealing using medium pressure. It is particularly suitable for handling high-pressure, pressure-fluctuating, and media containing particles that may abrade the packing. Its sealing effectiveness automatically increases with system pressure, making it suitable for harsh conditions. This division of labor allows both seals to maximize their effectiveness within their respective optimal operating ranges, collectively covering a wide range of applications from low to high pressure and from clean to particulate media, making the overall sealing reliability of the valve surpass that of any single sealing structure.

[0029] In Example 5, as a further preferred embodiment of Example 1, the elastic material of the upper valve stem sealing ring 6 and the lower valve stem sealing ring 8 is one of polytetrafluoroethylene (PTFE), reinforced PTFE, or flexible graphite. The listed materials (especially PTFE and its reinforced versions, and flexible graphite) all possess excellent self-lubricating properties. They can form a transfer film on the surface during friction, further reducing frictional resistance and wear on the mating metal surfaces, ensuring long-term stability of low-torque performance. Furthermore, these materials can undergo elastic or plastic deformation under relatively low pressure, perfectly filling the microscopic unevenness of metal surfaces such as valve stem shoulders and valve body steps, forming an initial seal. Their flexibility ensures rapid contact with the sealing surface even under low pressure or in the initial stages of pressure fluctuations. The materials also possess suitable compressive deformation capacity and a certain degree of resilience. When the medium pressure (axial force) increases, they can be further compressed, increasing the sealing specific pressure (pressure adaptive); when the pressure decreases, their resilience can partially compensate for the deformation, maintaining sealing contact and preventing instantaneous leakage due to sudden pressure drops.

[0030] In Example 6, as a further preferred embodiment of Example 1, the metal pressure ring 7 is made of stainless steel, alloy steel, or copper alloy. By using a metal material with excellent rigidity, such as stainless steel, alloy steel, or copper alloy, the metal pressure ring 7 ensures minimal deformation and maintains near-absolute geometric rigidity when subjected to the enormous axial thrust generated by the pressure of the entire medium in the valve cavity. This effectively and evenly transmits the axial pressure to the upper sealing ring 6 and the lower sealing ring 8 of the valve stem, ensuring that the sealing rings remain in a stable and uniform stress state throughout the entire pressure range, avoiding localized plastic failure or cracking due to stress concentration.

[0031] This invention adds a second pressure-adaptive seal, consisting of a thrust system, below the combined packing 4. The two seals are completely independent in structure, principle, and force source, forming a double safety guarantee. Even if the upper combined packing wears down due to long-term use, the lower thrust seal can still effectively block the medium, greatly extending the valve's leak-free operation cycle. The sealing force of the thrust system comes directly and proportionally from the valve cavity medium pressure. The higher the pressure, the automatically enhanced sealing specific pressure achieves a dynamic optimal match between sealing performance and operating pressure. This mechanism is particularly suitable for high-pressure and frequently fluctuating pressure applications, fundamentally solving the problems of insufficient sealing specific pressure under high pressure and excessive friction caused by pre-tightening force under low pressure in traditional structures. Furthermore, the axial concentrated load is dispersed through multiple parallel pressure-bearing planes, reducing the pressure on each contact surface and further reducing frictional resistance. The reduced torque allows for the use of a smaller power actuator, lowering the initial equipment cost; for manual operation, it greatly reduces the operational intensity and avoids the risk of valve stem breakage due to excessive torque.

[0032] The upper and lower valve stem sealing rings are made of elastic materials with self-lubricating properties, forming a transfer film on the friction surface to reduce frictional resistance and minimize wear on the metal surface. Simultaneously, the metal pressure ring acts as a rigid spacer, ensuring uniform force distribution and stable positioning of the upper and lower sealing rings, maintaining the parallelism of each bearing surface, and further reducing the operating torque required for valve stem rotation, making valve operation easier and more convenient. Regarding pressure adaptability, the thrust system exhibits "pressure self-adaptive" characteristics. When the medium pressure increases, the axial thrust increases, and the sealing specific pressure automatically increases accordingly; when the medium pressure decreases, the resilience of the sealing rings partially compensates for deformation, maintaining sealing contact and preventing instantaneous leakage due to sudden pressure drops. This characteristic allows the valve to automatically achieve optimal sealing performance across a wide range of operating conditions, from low to high pressure. In terms of structural reliability, the beveled convex ring and beveled groove form a stable mechanical interlocking connection between the sealing ring and the metal pressure ring on the valve stem. This effectively resists the relative rotation or lateral movement between components that may be caused by the circumferential force transmitted by the valve stem rotation or working vibration during valve opening and closing. This ensures that all components maintain precise coaxiality and relative positional relationship, avoiding local stress concentration or uneven sealing caused by component misalignment. Simultaneously, the metal pressure ring is made of a metal material with excellent rigidity and minimal deformation, enabling it to uniformly transmit axial pressure and ensuring stable stress distribution across the entire pressure range.

[0033] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A floating ball valve with a thrust system, comprising a valve body (1), a valve stem (2), a ball (3), and a combined packing (4) disposed in a stuffing box between the valve stem (2) and the valve body (1), wherein a valve stem shoulder (5) is provided on the outer surface of the valve stem (2), characterized in that: A thrust system is provided above the valve stem shoulder (5). The thrust system includes an upper valve stem sealing ring (6), a metal pressure ring (7), and a lower valve stem sealing ring (8) arranged sequentially from top to bottom. The upper valve stem sealing ring (6) and the lower valve stem sealing ring (8) are both made of elastic material, while the metal pressure ring (7) is made of rigid material. The metal pressure ring (7) is sandwiched between the upper valve stem sealing ring (6) and the lower valve stem sealing ring (8). The lower surface of the lower valve stem sealing ring (8) is in close contact with the upper surface of the valve stem shoulder (5), and the upper surface of the upper valve stem sealing ring (6) is in close contact with the internal step surface of the valve body (1).

2. A floating ball valve with a thrust system according to claim 1, characterized in that: The upper surface of the metal pressure ring (7) has a circumferentially circumferentially shaped groove (9); the lower surface of the valve stem sealing ring (6) is provided with a circumferentially shaped protruding ring (10) that cooperates with the circumferentially shaped groove; the circumferentially shaped protruding ring (10) is fitted into the circumferentially shaped groove (9).

3. A floating ball valve with a thrust system according to claim 2, characterized in that: The inclined surfaces of the inclined groove (9) and the inclined convex ring (10) are located on the outer side wall of the inclined groove (9) and the outer side wall of the inclined convex ring (10), respectively.

4. A floating ball valve with a thrust system according to claim 1, characterized in that: The thrust system is located below the combined packing (4) and together with the combined packing (4) at the axial position of the valve stem (2) forms two independent sealing structures.

5. A floating ball valve with a thrust system according to claim 1, characterized in that: The elastic material of the upper sealing ring (6) and the lower sealing ring (8) of the valve stem is one of polytetrafluoroethylene, reinforced polytetrafluoroethylene or flexible graphite.

6. A floating ball valve with a thrust system according to claim 1, characterized in that: The metal pressure ring (7) is made of stainless steel, alloy steel or copper alloy.

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