High-performance texture valve rod multi-layer packing sealing device

Abstract

A multilayer packing sealing device for a high-performance texture valve rod belongs to the technical field of packing sealing and is composed of a pre-tightening nut, a double-end stud, a valve body, a valve rod, a packing gland, upper packing, lower packing and multilayer sealing packing located between the upper packing and the lower packing. And micro-texture machining design is carried out on the surface of the valve rod. The packing gland is connected with the valve body through the pre-tightening nut and the double-end stud, when the pre-tightening nut is screwed downwards, pre-tightening force is applied to the multiple layers of sealing packing through the packing gland and the upper packing, the lower packing supports the multiple layers of sealing packing, and contact pressure is generated on the contact faces between the multiple layers of sealing packing and the valve rod and between the multiple layers of sealing packing and the valve body. And leakage of lubricant in the valve is prevented. By designing and processing the microtexture on the surface of the valve rod, various properties are improved, the sealing effect is improved, and the valve rod has good material aging resistance, can be applied to occasions needing valve sealing in industrial production and has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of packing seals, and relates to a high-performance textured valve stem multi-layer packing seal device capable of improving sealing capability, resisting material aging, and reducing friction torque, and in particular to the application of the tribological properties of surface micro-texture in this field. Background Art

[0002] Valve stem packing seal is the most commonly used type of seal. Most sealing media have the characteristics of high temperature, high pressure, corrosion, flammability and explosion. The valve stem packing seal is a high-risk source of leakage of the valve system. If it leaks, it will cause serious accidents such as environmental pollution, casualties, and equipment shutdown, and even cause major safety accidents such as fire and explosion. It can be seen that the performance of the valve stem packing seal is one of the key factors restricting the long-term stable operation of the equipment.

[0003] Traditional valve stem packing sealing methods are mostly continuous surface contact, which has many disadvantages in practical applications. From the perspective of sealing performance, due to the micro-roughness and unevenness of the material surface, continuous surface contact makes most of the contact pressure concentrated in a few areas, and the effective sealing area is small, which is easy to cause sealing failure or aggravate friction and wear. Especially under high pressure and high temperature conditions, traditional sealing methods are difficult to meet the needs of stable sealing. In terms of material aging, the packing material will gradually age and its elasticity will decrease with the increase of usage time or in harsh environments. After the packing ages, the traditional sealing structure cannot effectively respond to changes in pressure distribution because the contact method has not changed, resulting in a rapid decline in sealing performance.

[0004] In addition, the traditional flat contact valve stem and packing generate friction on the entire contact surface, which increases the energy consumption and mechanical wear of valve operation, affects the operating flexibility and accuracy of the valve, and reduces the overall performance and efficiency of the system.

[0005] Therefore, inventing a valve stem packing sealing device that can improve sealing ability, resist material aging and reduce friction torque has become a key issue to be urgently addressed in the field of packing sealing technology. The emergence of micro-texture technology provides a new direction for solving these problems. Summary of the invention

[0006] In response to the problems existing in the prior art, the present invention provides a high-performance textured valve stem multi-layer packing sealing device, which, by processing micro-texture on the valve stem surface, can improve the sealing performance, enhance the ability to resist material aging, and reduce friction torque, thereby ensuring the safety and stability of the system and extending the service life of industrial equipment.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] A high-performance textured valve stem multi-layer packing sealing device, which is mainly composed of a pre-tightening nut 1, a stud 2, a valve body 3, a valve stem 4, a packing gland 5, an upper packing 6, a lower packing 7 and a multi-layer sealing packing located between the upper packing 6 and the lower packing 7. The gap between the valve stem 4 and the valve body 3 is sealed by the multi-layer sealing packing.

[0009] The surface of the valve stem 4 is processed and designed with micro textures, and a series of micro textures are arranged on the surface. The specific schematic diagram of the valve stem packing sealing structure is as follows: Figure 2 shown.

[0010] The gap between the valve stem 4 and the valve body 3 is equipped with an upper packing 6, a lower packing 7 and multiple layers of sealing packing 8-13. The upper packing 6 and the lower packing 7 are respectively placed at the upper and lower ends of the sealing packing 8-13, wherein the upper packing 6 is used to transfer the pre-tightening force from the pre-tightening nut to the sealing packing 8-13 below, and the lower packing provides support for the sealing packing 8-13, thereby achieving a tight fixation of the sealing packing 8-13. The sealing packing 8-13 is installed sequentially from bottom to top, corresponding to different installation layers, and each layer of sealing packing has the same thickness, wherein the packing 8 corresponds to the first layer installation position, the packing 9 corresponds to the second layer installation position, and the installation positions of the remaining packings are similar, so as to achieve a multi-layer packing sealing effect. Each layer of sealing packing is designed as a V-shaped structure and uses different colors, and the inter-layer identification is achieved through the cutting angles and color differences of the packings of different layers.

[0011] The packing gland 5 is connected to the valve body 3 through the pre-tightening nut 1 and the stud 2. When the pre-tightening nut 1 is screwed downward, a pre-tightening force is applied to the sealing packings 8-13 through the packing gland 5 and the upper packing 6, and the lower packing 7 provides support for the sealing packings 8-13, thereby generating axial compression on the sealing packings 8-13, causing axial and radial deformation, and generating contact pressure on the contact surface between the sealing packings 8-13 and the valve stem 4 and the valve body 3, thereby forming a blockage to prevent the lubricant inside the valve from leaking out.

[0012] Furthermore, when the contact pressure generated on the contact surfaces between the sealing packings 8 to 13 and the valve stem 4 and the valve body 3 is greater than the lubricant fluid pressure, a sealing effect can be achieved.

[0013] Furthermore, after the valve stem 4 moves for a long time and causes the sealing packings 8 to 13 to wear and become loose, the packings are tightened again by adjusting the pre-tightening nut 1 .

[0014] Furthermore, the series of micro-textures arranged on the surface of the valve stem 4 include multiple rows of texture structures, each row of texture structures is distributed along the surface generatrix of the valve stem 4, and is evenly distributed on the annular surface of the valve stem 4 in the circumferential direction, and is in contact with the sealing packing.

[0015] Furthermore, each column of the texture structure is composed of multiple rectangular grooves distributed at intervals. The width of the rectangular groove ranges from 0.02 to 0.1 mm, and the depth of the groove ranges from 0.01 to 0.05 mm, which has the effect of improving fluid lubrication.

[0016] Furthermore, the material of the sealing packing is polytetrafluoroethylene (PTFE).

[0017] An implementation method of a high-performance textured valve stem multi-layer packing seal device mainly realizes the change of the contact surface form and the complication and three-dimensionalization of the contact mode between the sealing packing 8 - 13 and the valve stem 4 by micro-texturing the surface of the valve stem 4, thereby realizing the improvement of the sealing ability and anti-material aging performance of the valve stem packing seal device and the reduction of the friction torque, achieving the purpose of ensuring the safety and stability of the system and extending the service life of industrial equipment.

[0018] The specific working principle and innovation points of the present invention are as follows:

[0019] The grooves of the micro-texture on the valve stem surface increase the effective contact area with the packing and change the contact pressure distribution. It avoids the problem of local high-pressure concentration in the traditional continuous surface contact, making the pressure distribution more balanced; when the packing ages during long-term service, it can still maintain a relatively high contact pressure, slowing down the pressure drop caused by packing aging. In addition, the micro-texture reduces the contact area between the packing and the valve stem, thereby reducing the friction torque. The micro-texture grooves can capture and retain lubricating fluid to form an oil film, reducing the direct frictional contact between the valve stem and the packing. At the same time, the optimized pressure distribution avoids local high friction, jointly reducing the friction torque.

[0020] The present invention designs a micro-texture on the valve stem surface, breaking the traditional continuous surface contact mode between the valve stem and the packing, and using grooves to form a complex three-dimensional contact, fundamentally changing the action mechanisms of sealing and friction. It can still effectively increase the sealing contact pressure under the condition of material aging, while reducing the friction torque, solving the problems of large friction torque of traditional sealing devices and the decline of sealing performance after material aging, greatly improving the reliability and durability of the sealing device, and realizing structural innovation and performance improvement.

[0021] The beneficial effects of the present invention are as follows:

[0022] Through the micro-texture design and processing on the surface of the valve stem, the present invention realizes the improvement of various performances. In terms of sealing performance, the micro-texture on the valve stem can increase the effective contact area and the number of contacts of the contact surface, change the contact pressure distribution, avoid local pressure concentration, and greatly improve the sealing effect; after the packing ages, the micro-texture can still maintain a relatively high contact pressure, slow down the decline of the sealing performance, and endow the sealing device with good anti-material aging ability. In terms of the frictional torque, the micro-texture surface can reduce the actual contact area, and its grooves can accumulate the medium to form a lubricating film and achieve a uniform distribution of the frictional force, thereby effectively reducing the frictional torque, reducing energy consumption and equipment wear, and prolonging the service life of the equipment. The present invention can be applied to the occasions where valve sealing is required in industrial production and has good practicability. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall assembly of the valve;

[0024] Figure 2 It is a schematic diagram of the valve stem packing seal structure of the present invention;

[0025] Figure 3 It is a partially enlarged schematic diagram of the valve stem packing seal of the present invention;

[0026] Figure 4 It is a partially enlarged schematic diagram of the micro-texture on the surface of the valve stem of the present invention; Figure 4 (a) It is a schematic diagram of the surface of the valve stem processed with micro-texture; Figure 4 (b) It is a schematic diagram of the surface of the valve stem without micro-texture processing;

[0027] Figure 5 It is a schematic diagram of the stress and strain of the packing material adopted by the present invention under different aging degrees;

[0028] Figure 6 It is a schematic diagram of the contact pressure of each sealing packing of the present invention without considering aging and with different micro-textures; Figure 6 (a) It is a schematic diagram of the contact pressure of packing 8 with different micro-textures; Figure 6 (b) It is a schematic diagram of the contact pressure of packing 9 with different micro-textures; Figure 6 (c) It is a schematic diagram of the contact pressure of packing 10 with different micro-textures; Figure 6 (d) It is a schematic diagram of the contact pressure of packing 11 with different micro-textures; Figure 6 (e) It is a schematic diagram of the contact pressure of packing 12 with different micro-textures; Figure 6 (f) It is a schematic diagram of the contact pressure of packing 13 with different micro-textures;

[0029] Figure 7 It is a schematic diagram of the maximum contact pressure of each sealing packing of the present invention under different aging degrees; Figure 7(a) Schematic diagram of the maximum contact pressure of each sealing packing under non-aged conditions; Figure 7 (b) Schematic diagram of the maximum contact pressure of each sealing packing under the condition of aging for 2 days; Figure 7 (c) Schematic diagram of the maximum contact pressure of each sealing packing under the condition of aging for 6 days; Figure 7 (d) Schematic diagram of the maximum contact pressure of each sealing packing under the condition of aging for 10 days;

[0030] Figure 8 Schematic diagram of the total frictional torque of each sealing packing of the present invention under different aging degrees and different micro-textures; Figure 8 (a) Schematic diagram of the total frictional torque of different micro-textures of each sealing packing under non-aged conditions; Figure 8 (b) Schematic diagram of the total frictional torque of different micro-textures of each sealing packing under the condition of aging for 2 days; Figure 8 (c) Schematic diagram of the total frictional torque of different micro-textures of each sealing packing under the condition of aging for 6 days; Figure 8 (d) Schematic diagram of the total frictional torque of different micro-textures of each sealing packing under the condition of aging for 10 days.

[0031] In the figure: 1 pre-tightening nut; 2 stud; 3 valve body; 4 valve stem; 5 packing gland; 6 upper packing; 7 lower packing; 8-13 are 6 layers of sealing packings installed from bottom to top; 14 width of the micro-texture groove on the valve body surface; 15 depth of the micro-texture groove on the valve body surface. Specific embodiments

[0032] The technical solutions of the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0033] Figure 1 It is a schematic diagram of the overall assembly of the valve. The valve stem packing seal device cooperates with the actuator to complete the overall seal of the system.

[0034] Figure 2 Schematic diagram of the valve stem packing seal structure adopted by the present invention, as Figure 2As shown in the figure, the device of this embodiment includes a pre-tightening nut 1, a stud 2, a valve body 3, a valve stem 4, a packing gland 5, an upper packing 6, a lower packing 7, and six layers of sealing packing 8-13. The stud 2 connects the valve body 3 and the packing gland 5. The pre-tightening nut 1 cooperates with the stud 2 and applies a pre-tightening force to the sealing packing 8-13 through the packing gland 5 and the upper packing 6. The lower packing 7 provides support for the sealing packing 8-13, causing the sealing packing 8-13 to deform towards the inner sides of the valve stem 4 and the valve body 3, thereby generating a contact pressure on the contact surface. When the contact pressure is greater than the fluid pressure of the lubricant, it plays a sealing role.

[0035] Figure 3 This is a partially enlarged schematic diagram of the valve stem packing seal of the present invention. As Figure 3 shown, in the gap between the valve stem 4 and the valve body 3, there are an upper packing 6, a lower packing 7, and sealing packing 8-13. The upper packing 6 and the lower packing 7 are respectively placed at the upper and lower ends of the sealing packing 8-13 to tightly fix the sealing packing 8-13. After the pre-tightening nut 1 applies a load to the packing 8-13 through the packing gland 5 and the upper packing 6, a contact pressure is generated between the sealing packing 8-13 and the valve stem 4 and the valve body 3, preventing the leakage of the internal lubricant of the valve. After the long-term movement of the valve stem 4 causes the sealing packing 8-13 to wear and loosen, the pre-tightening nut 1 can be adjusted to tighten the packing again.

[0036] Figure 4 This is a partially enlarged schematic diagram of the micro-texture on the surface of the valve stem of the present invention. As Figure 4 shown, the micro-texture on the surface of the valve stem is mainly rectangular, and the groove width 14 and groove depth 15 of the micropores can be designed. Different groove widths 14 and groove depths 15 can obtain different degrees of sealing performance. In this embodiment, each column of the texture structure is composed of a plurality of rectangular grooves distributed at intervals. The range of the rectangular groove width 14 is 0.02-0.1 mm, and the range of the groove depth 15 of the micro-texture on the valve body surface is 0.01-0.05 mm, which has the effect of improving fluid lubrication.

[0037] Figure 5 This is a stress-strain schematic diagram of the packing material adopted by the present invention under different aging degrees. The materials of the upper packing 6, the lower packing 7, and the six layers of sealing packing 8-13 are all PTFE, and the six layers of sealing packing 8-13 have the same thickness.

[0038] The present invention proposes a high-performance textured valve stem multi-layer packing seal device that can improve the sealing ability, resist material aging, and reduce the friction torque, and will explain the performance improvement from three aspects.

[0039] First, in terms of improving the sealing ability: Without considering material aging, machining micro-textures on the valve stem surface can enhance the sealing ability of the device. Conventional valve stems and packings usually achieve sealing through continuous surface contact. Most of the contact pressure is concentrated in a small area on the contact surface. Due to the microscopic roughness and non-uniformity of the material surface, such a contact method results in only a small area having a high contact pressure, and the effective sealing area is small. By machining micro-textures on the valve stem surface, the effective contact area of the contact surface can be significantly increased, and the contact pressure on each effective contact surface will also increase. The groove distribution of the micro-texture structure can form more effective contact areas, greatly increasing the effective contact area during the sealing process. Especially under high-pressure or high-temperature working conditions, the sealing performance can be effectively improved. In addition, the grooves on the valve stem surface micro-texture can change the contact surface morphology, making the contact method between the packing and the valve stem more complex and three-dimensional, resulting in the contact pressure distribution no longer being a simple uniform distribution, but becoming more balanced and having a higher local contact pressure. When the packing contacts the valve stem surface, the micro-texture on the valve stem surface will change the contact pressure distribution. Specifically, the groove part will form a local low-pressure area during the contact process, while the raised part will concentrate the local high pressure.

[0040] Figure 6 Schematic diagram of the contact pressure of each sealing packing of the present invention without considering aging and different micro-textures; the data in this figure is obtained through ANSYS software simulation. First, establish a simulation model as shown in Figure 3 in ANSYS. Fix the valve body 3 and the valve stem 4, and model the micro-texture features on the surface of the valve stem 4. The packing and the valve stem, the packing and the valve body, and between each layer of packing are all friction constraints, and the friction coefficient is set to 0.1. Then, use the comparative analysis method to carry out numerical simulation experiments. First, construct a non-textured state as a reference model for basic simulation. Subsequently, based on the parametric research method, sequentially set the micro-texture groove width 14 on the valve body surface to three parameters of 0.02 mm, 0.06 mm, and 0.10 mm, and conduct three independent simulation simulations respectively. During each simulation process, apply a pre-tightening force of 500 N to the sealing packing 8-13 through the packing gland 5 and the upper packing 6. After the simulation calculation converges, extract the contact pressure between each layer of packing and the valve stem as the evaluation index. As shown in Figure 6 , which includes six subgraphs, corresponding to the 6-layer sealing packing 8-13 without texture and with a texture groove depth of 0.01 mm and a texture groove width h aThe contact pressures under the four cases of 0.02 mm, 0.06 mm, and 0.1 mm are reflected by four curves in each sub - figure to represent the changing trend of contact pressure with the change of contact width. By comparing the sub - figure curves under each packing, it is obtained that: compared with the non - textured case, the contact pressure increases when the valve stem 4 has micro - textures on its surface, and with the increase of the width h a of the micro - texture groove, the contact pressure increases significantly. Under different sealing packings, the maximum contact pressure of the structure design with the micro - texture groove width h a = 0.1 mm is increased by 141.38%, 139.17%, 138.36%, 144.58%, 142.48%, and 142.95% respectively compared with the non - textured case. This indicates that the pressing force on the contact surface can resist the separating force generated by the lubricant fluid pressure to a greater extent, further narrowing the gap area where the lubricant may leak, making the contact of the sealing surface closer, and thus improving the sealing performance of the valve stem packing.

[0041] Second, in terms of anti - material aging: Considering the case of material aging, the valve stem with micro - textures can still increase the contact pressure and slow down the decline of sealing performance caused by material aging, thereby achieving the effect of anti - material aging. The micro - textures change the contact mode between the packing and the valve stem by increasing the grooves on the valve stem surface, making the contact no longer a simple planar contact. Even if the packing material ages, under the influence of the micro - textures, the raised parts on the valve stem surface will locally concentrate the contact pressure and still exert a large pressure on the packing, which enables the contact pressure to remain at a relatively high value continuously, helping to slow down the decrease in contact pressure due to material aging. In addition, the micro - textures increase the number of contacts. By dispersing the contact pressure, the contact pressure between the packing and the valve stem becomes more uniform. When the packing ages, the material elasticity decreases, but due to the increase in the number of contact points, the concave - convex structure of the micro - textured valve stem can still provide more effective contacts, and the contact pressure between the packing and the valve stem is still higher than that of the valve stem with a smooth surface. These contact points can make the pressure distribute more evenly on the contact surface between the packing and the valve stem, avoid the problem of pressure concentration in some areas caused by packing aging, maintain a better sealing effect, prevent the rapid decline of contact pressure, reduce the negative impact of material hardening on the sealing effect, and thus improve the anti - material aging ability of the valve stem packing sealing system.

[0042] The sealing packing material 8 - 13 adopted in the present invention is PTFE, and the stress - strain conditions of this material under different aging degrees are as Figure 5As shown in the figure, the six curves in the figure respectively represent the stress-strain change trends of the material without aging and after aging at 300°C for 2 days, 4 days, 6 days, 8 days, and 10 days. It can be seen from the figure that as the aging time increases, the stress at the same strain gradually decreases, and the slope of the curve also changes, reflecting the influence of aging time on the elastic modulus of the material. The longer the aging time, the smaller the elastic modulus of the material, which means the material becomes softer and its ability to resist deformation decreases.

[0043] Figure 7 This is a schematic diagram of the maximum contact pressure of various sealing fillers of the present invention under different aging degrees; as Figure 7 shown, take no aging, aging for 2 days, aging for 6 days, and aging for 10 days as the four states of no, general, relatively heavy, and very heavy aging degrees, and respectively show the change trends of the maximum contact pressures of three kinds of fillers under different micro-texture parameters at these four aging degrees. The data in this figure is obtained through ANSYS software simulation. First, establish a simulation model as Figure 3 shown in the figure, fix the valve body 3 and the valve stem 4, and model the micro-texture features on the surface of the valve stem 4. There are friction constraints between the filler and the valve stem, between the filler and the valve body, and between each layer of fillers, and the friction coefficient is set to 0.1. To characterize the material aging effect, the constitutive parameters of the sealing filler at four aging cycles of 0 days (not aged), 2 days, 6 days, and 10 days are obtained through an accelerated aging test, and four groups of independent simulation working conditions are established accordingly. Under each working condition, then sequentially set the width 14 of the micro-texture groove on the valve body surface to four parameters of 0 mm (no texture), 0.02 mm, 0.06 mm, and 0.10 mm, so as to form 16 simulation experiments. During each simulation experiment, a pre-tightening force of 500 N is applied to the sealing filler 8-13 through the packing gland 5 and the upper packing 6. When the simulation calculation converges, the maximum value of the contact pressure between each layer of filler and the valve stem is extracted as the evaluation index. By comparing the broken line information of the subgraphs of each aging degree, it is concluded that regardless of the aging degree, the maximum contact pressure in the case of no texture is less than that with texture. Taking the sealing filler 13 as an example, at the four aging degrees, compared with no texture, when the texture groove width h a = 0.1 mm, the maximum contact pressures are increased by 142.95%, 143.27%, 143.02%, and 143.69% respectively. This shows that the slowdown rate of the tight pressure on the contact surface when aging can be minimized, further improving the duration of the high contact pressure, reducing the negative impact of material hardening on the sealing effect, and thus greatly improving the anti-aging ability of the material; just looking at one of the subgraphs, as the width of the micro-texture groove increases, the maximum contact pressure also increases significantly, which further highlights the significant influence of the surface micro-texture on the contact pressure.

[0044] Third, in terms of reducing the frictional torque: Whether there is aging or not, the presence of micro-textures in the valve stem machining can reduce the frictional torque. The micro-textured surface presents a structure of protrusions and grooves, which changes the contact mode between the packing and the valve stem, significantly reducing the actual contact area. Since the frictional torque is proportional to the contact area, the reduction of the contact area directly promotes the decrease of friction, thereby reducing the frictional torque. In addition, the grooves and channels of the micro-textures have the ability to capture and retain the lubricating fluid, which is conducive to the formation of a stable oil film, effectively reducing direct frictional contact. Under the action of lubricating oil or lubricating medium, it is beneficial to reduce the friction coefficient and frictional resistance, and further reduce the frictional torque. When there is no micro-texture, the contact surface is prone to generate excessive pressure locally due to surface irregularities, resulting in a large frictional force at some contact points. The micro-texture can increase the number of contacts and optimize the pressure distribution, making the friction more uniform, avoiding excessive local frictional force, and ultimately reducing the frictional torque.

[0045] Figure 8 This is a schematic diagram of the total frictional torque of each sealing packing of the present invention under different aging degrees and different micro-textures; as Figure 8 shown, taking 0 days (non-aged), 2 days, 6 days, and 10 days of aging as the four states of non-aged, general, severe, and very severe aging degrees, the changing trends of the total frictional torque of each sealing packing under different micro-texture parameters at these four aging degrees are respectively shown. The data in this figure is obtained through ANSYS software simulation. First, establish a simulation model as Figure 3 shown in ANSYS, fix the valve body 3 and the valve stem 4, and model the micro-texture features on the surface of the valve stem 4. There are frictional constraints between the packing and the valve stem, between the packing and the valve body, and between each layer of packing, and the friction coefficient is set to 0.1. Considering the coupling effect of material aging and surface micro-texture, a double control variable method is used for simulation numerical experiments. In terms of material aging, based on the accelerated aging test, the constitutive parameters of the sealing packing at four aging cycles of 0 days (non-aged), 2 days, 6 days, and 10 days are obtained, and a material database is established; in terms of surface micro-texture, a parametric design method is adopted, and the groove width 14 of the micro-texture on the valve stem surface is set to four parameter values of 0 mm (no texture), 0.02 mm, 0.06 mm, and 0.10 mm, and 4 groups of surface topography comparison models are constructed. Through the orthogonal experimental design, 4 material states and 4 surface micro-texture parameters are combined to form 16 independent simulation working conditions. For each working condition, a pre-tightening force of 500 N is applied to the sealing packing 8-13 through the packing gland 5 and the upper packing 6. Under the action of the pre-tightening force, a certain contact pressure will be generated on the contact surface between the packing and the valve stem. Considering that the contact surface is a non-smooth topography, a frictional torque that hinders the rotation of the valve stem will be generated when the valve stem rotates. The calculation formula for the frictional torque corresponding to each layer of packing is:

[0046]

[0047] Wherein, R is the radius of the valve stem, v is the friction coefficient, L is the packing height, and p y is the contact pressure of the packing.

[0048] The total frictional torque M of each layer of packing on the valve stem s is:

[0049]

[0050] According to formulas (1) and (2), it can be known that by extracting the corresponding parameter values in the ANSYS simulation experiment and performing integral operation on the contact pressure of each layer of packing in the contact width, the corresponding frictional torque can be obtained. After that, by accumulating the frictional torques of each layer of packing, the total frictional torque can be obtained.

[0051] By comparing the information of the columnar subgraphs of each aging degree, it is concluded that regardless of the aging degree, compared with the non-textured case, the total frictional torque in the textured case has decreased to a certain extent. For different aging degrees, when the width h of the texture groove a = 0.1 mm, the total frictional torque has decreased by 29.71%, 38.2%, 29.75%, and 28.98% respectively compared with the non-textured case; just looking at the subgraph of one aging degree, as the width of the micro-texture groove increases, the frictional torque also decreases accordingly, further reflecting the effectiveness of the micro-texture on the valve stem surface in reducing the frictional torque.

[0052] The above-described embodiments only represent the implementation manners of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A high-performance textured valve stem multi-layer packing sealing device, characterized in that: The high-performance textured valve stem multi-layer packing sealing device mainly comprises a pre-tightening nut (1), a stud (2), a valve body (3), a valve stem (4), a packing gland (5), an upper packing (6), a lower packing (7) and a multi-layer sealing packing located between the upper packing (6) and the lower packing (7), and the gap between the valve stem (4) and the valve body (3) is sealed by the multi-layer sealing packing; The surface of the valve stem (4) is processed and designed with micro textures, and a series of micro textures are arranged on the surface; An upper filler (6), a lower filler (7) and a multi-layer sealing filler are installed in the gap between the valve stem (4) and the valve body (3). The upper filler (6) and the lower filler (7) are respectively placed at the upper and lower ends of the multi-layer sealing filler to achieve tight fixation of the multi-layer sealing filler. The packing gland (5) is connected to the valve body (3) via a pre-tightening nut (1) and a stud (2). When the pre-tightening nut (1) is turned downward, a pre-tightening force is applied to the multi-layer sealing packing via the packing gland (5) and the upper packing (6). The lower packing (7) provides support for the multi-layer sealing packing, thereby generating axial compression on the multi-layer sealing packing, causing axial and radial deformation of the multi-layer sealing packing, generating contact pressure on the contact surface between the multi-layer sealing packing and the valve stem (4) and the valve body (3), forming a blockage, and preventing the lubricant inside the valve from leaking out.

2. A high performance textured valve stem multi-layer packing sealing device according to claim 1, characterized in that: The multi-layer sealing filler is installed in sequence from bottom to top, and each layer of sealing filler has the same thickness, thereby achieving a multi-layer filler sealing effect; each layer of sealing filler is designed as a V-shaped structure and uses different colors, and inter-layer identification is achieved through the cutting angles of different layers of fillers and the color differences.

3. A high performance textured valve stem multi-layer packing sealing device according to claim 1, characterized in that: When the contact pressure generated on the contact surface between the multi-layer sealing packing and the valve stem (4) and the valve body (3) is greater than the lubricant fluid pressure, a sealing effect can be achieved.

4. A high performance textured valve stem multi-layer packing sealing device according to claim 1, characterized in that: After the valve stem (4) moves for a long time and causes the multi-layer sealing packing to wear and loosen, the packing is tightened again by adjusting the pre-tightening nut (1).

5. A high performance textured valve stem multi-layer packing sealing device according to claim 1, characterized in that: The series of micro-textures arranged on the surface of the valve stem (4) include multiple rows of texture structures, each row of texture structures is distributed along the surface generatrix of the valve stem (4), and is evenly distributed on the annular surface of the valve stem (4) in the circumferential direction and is in contact with the sealing packing.

6. A high performance textured valve stem multi-layer packing sealing device according to claim 5, characterized in that: Each row of texture structure consists of a number of rectangular grooves distributed at intervals.

7. A high performance textured valve stem multi-layer packing sealing device according to claim 6, characterized in that: The rectangular groove width 14 ranges from 0.02 to 0.1 mm, and the groove depth 15 ranges from 0.01 to 0.05 mm.

8. A high performance textured valve stem multi-layer packing sealing device according to claim 1, characterized in that: The material of the sealing filler is polytetrafluoroethylene (PTFE).

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