Modular cartridge-type composite valve stem sealing device and its sealing force compensation method

Abstract

This application discloses a modular cartridge-type composite valve stem sealing device and its sealing force compensation method, relating to the field of industrial valve sealing technology, to solve the problems of uneven sealing contact and decreased sealing performance caused by valve stem misalignment, posture changes, and wear of sealing materials. The device includes a cartridge housing, a main sealing assembly, and a self-compensating assembly. The main sealing assembly includes a main sealing ring, a floating support ring, and a spherical guide surface, enabling the main sealing ring to float radially and oscillate at an angle. The self-compensating assembly includes a disc spring assembly and a push ring, which compensates for wear and axial position changes of the main sealing ring by continuously applying axial preload, thereby maintaining valve stem sealing contact through radial, angular, and axial coordinated compensation.

Description

Technical Field

[0001] This application relates to the field of industrial valve sealing technology, and in particular to a modular cartridge-type composite valve stem sealing device and its sealing force compensation method, which can be applied to the valve stem sealing of industrial valves such as gate valves, ball valves, globe valves, and butterfly valves. Background Technology

[0002] Industrial valves are widely used in power, petrochemical, metallurgical, energy, and fluid transportation industries. The valve stem, as a crucial moving part that performs opening, closing, or regulating actions, typically requires a sealing structure between the stem and the valve cover or stuffing box to limit leakage of the working medium along the stem. Existing valve stem seals usually employ flexible graphite, polytetrafluoroethylene (PTFE), and other composite materials to form packing or sealing rings. An axial clamping force is applied to the sealing material through the valve gland, causing the sealing material to radially press against the valve stem surface to form a sealing contact. For high-temperature, high-pressure, or frequent opening and closing conditions, multi-layer sealing materials, elastic loading structures, backup sealing structures, and dustproof / scraping structures can also be used to meet the sealing requirements of different valves.

[0003] However, during long-term valve operation, the valve stem may experience radial offset or axial angle changes due to machining errors, installation errors, wear, and deformation under stress. Traditional sealing structures typically have sealing rings with fixed installation positions, making it difficult to adjust them according to changes in the valve stem's position and orientation. This can easily lead to localized uneven loading on the sealing contact surface, increasing local contact pressure and exacerbating wear, while other areas experience insufficient contact pressure. Simultaneously, with wear, creep, and thermal deformation of the sealing material, the original axial clamping amount gradually changes, further affecting the sealing contact state. Therefore, how to simultaneously adapt to both radial and angular offsets of the valve stem, and continuously compensate for the sealing clamping amount when the sealing material wears or its axial position changes, in order to maintain a relatively uniform and stable valve stem sealing contact, is a problem that existing valve stem sealing technology needs to solve. Summary of the Invention

[0004] This application is entitled "Modular Casing-Type Composite Valve Stem Sealing Device and its Sealing Force Compensation Method". This application mainly addresses the technical problem that in existing valve stem sealing structures, when the valve stem experiences radial or angular displacement, or when the sealing material wears or its axial position changes, the sealing ring cannot adaptively adjust to the position and posture of the valve stem, leading to uneven sealing contact, localized wear, and decreased sealing performance.

[0005] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides a modular cartridge-type composite valve stem sealing device, including a cartridge housing for installation within a valve stuffing box, a main sealing assembly disposed within the cartridge housing and fitted around the valve stem, and a self-compensating assembly. The cartridge housing has a central through hole through which the valve stem passes. The main sealing assembly includes a main sealing ring, a floating support ring for supporting the main sealing ring, and a spherical guide surface for guiding the attitude of the main sealing ring. The floating support ring is configured to allow the main sealing ring to radially float and angularly swing relative to the cartridge housing, so that the main sealing ring adjusts its sealing position according to the radial and angular offset of the valve stem. The self-compensating assembly includes a disc spring assembly and a push ring disposed between the disc spring assembly and the main sealing assembly. The disc spring assembly continuously applies a preload along the valve stem axial direction to the main sealing ring through the push ring, and drives the main sealing ring to generate axial compensation displacement when the main sealing ring wears or its axial position changes, so that the radial floating, angular swing, and axial compensation displacement of the main sealing ring cooperate with each other to maintain the sealing contact between the main sealing ring and the valve stem.

[0006] As a further improvement of this application, a labyrinth pressure reducing assembly is also provided inside the cartridge housing. The labyrinth pressure reducing assembly is located between the medium side and the main sealing assembly along the leakage path of the medium flowing towards the main sealing assembly. The labyrinth pressure reducing assembly has multiple pressure reducing sections connected sequentially along the leakage path, so that the medium is pressure reduced step by step through multiple pressure reducing sections before reaching the main sealing ring.

[0007] As a further improvement of this application, the labyrinth pressure reducing assembly includes a primary labyrinth ring, a secondary labyrinth ring, a tertiary labyrinth ring, and a limiting ring. The primary, secondary, and tertiary labyrinth rings are arranged along the axial direction of the valve stem and together form a stepped labyrinth channel with multiple pressure reducing sections. The limiting ring is used to axially limit the primary, secondary, and tertiary labyrinth rings.

[0008] As a further improvement of this application, a graphite backup assembly is also provided inside the cartridge housing. The graphite backup assembly is located on the side of the main sealing assembly facing the atmosphere and includes a flexible graphite ring and a metal reinforcing ring disposed on the flexible graphite ring, so as to form a redundant seal when the sealing capacity of the main sealing ring is reduced due to high temperature, aging or damage.

[0009] As a further improvement of this application, the main sealing ring is made of a composite material containing highly filled polytetrafluoroethylene, graphite and carbon fiber, and the surface of the main sealing ring is provided with a microporous ceramic coating.

[0010] As a further improvement of this application, a compensation ring groove is provided on the outer periphery of the cartridge housing, and an elastic compensation ring is provided in the compensation ring groove. The elastic compensation ring is a corrugated metal ring or an open elastic ring, which is used to compensate for the dimensional deviation between the cartridge housing and the valve stuffing box, stuffing box wear, or installation misalignment through its own elastic deformation.

[0011] As a further improvement of this application, a dustproof and dirt-removing assembly is also provided inside the cartridge housing. The dustproof and dirt-removing assembly includes a primary dustproof lip, a secondary dustproof lip, and a dirt-removing ring arranged along the valve stem axial direction. The dirt-removing ring is made of silicon carbide or alumina ceramic material and is used to remove dust, coke, crystals, or particulate matter adhering to the valve stem surface.

[0012] As a further improvement of this application, the cartridge housing is provided with a quick-installation assembly, which includes a guide cone, a locating pin, a snap-fit ​​groove, and a mis-proof mark. The guide cone is used to guide the cartridge housing into the valve stuffing box, the locating pin is used to define the installation position of the cartridge housing, the snap-fit ​​groove is used to cooperate with the locking structure on the valve gland side, and the mis-proof mark is used to indicate the installation direction of the cartridge housing.

[0013] As a further improvement of this application, the cartridge housing is also provided with a monitoring component, which includes a displacement scale rod, an observation window, a pressure sensor, a temperature sensor and a wiring interface. The displacement scale rod is correspondingly set with the self-compensation component and is used to characterize the compression state of the disc spring assembly. The observation window is used to display the position of the displacement scale rod. The pressure sensor and temperature sensor are used to detect the pressure parameters and temperature parameters of the sealing device, respectively.

[0014] Secondly, this application provides a sealing force compensation method implemented using the above-mentioned modular cartridge-type composite valve stem sealing device, comprising: installing the cartridge housing into the valve stuffing box, and allowing the valve stem to pass through the cartridge housing and the main sealing ring; forming a sealing contact between the main sealing ring and the valve stem; when the valve stem undergoes radial displacement, causing the main sealing ring to radially float relative to the cartridge housing through the floating support ring to adjust the radial sealing position of the main sealing ring relative to the valve stem; when the valve stem undergoes angular displacement, guiding the main sealing ring to angularly swing through the spherical guide surface to adjust the sealing posture of the main sealing ring relative to the valve stem; continuously applying a preload along the valve stem axial direction to the main sealing ring through the disc spring assembly via the push ring, and when the main sealing ring experiences wear, material creep, or axial position change, using the elastic displacement of the disc spring assembly to drive the push ring and the main sealing ring to generate a compensating displacement along the valve stem axial direction; and coordinating the radial floating, angular swing, and axial compensating displacement of the main sealing ring to maintain the sealing contact between the main sealing ring and the valve stem.

[0015] Compared with the prior art, this application has at least the following beneficial effects: The floating support ring allows the main sealing ring to float radially relative to the cartridge housing, and the spherical guide surface guides the main sealing ring's attitude, enabling the main sealing ring to adjust its sealing position according to the radial and angular offset of the valve stem. This reduces the possibility of localized off-center loading of the sealing ring due to valve stem eccentricity or axial deflection, and helps improve the uniformity and stability of the sealing contact.

[0016] By forming a continuous axial elastic loading path through the disc spring assembly and the push ring, when the main sealing ring experiences wear, material creep, or axial position changes due to long-term operation, the elastic displacement of the disc spring assembly automatically compensates for the axial displacement of the main sealing ring, enabling the main sealing ring to continuously maintain the required sealing contact state with the valve stem and reducing the risk of leakage caused by the decrease in sealing preload over time.

[0017] By combining the radial floating, angular oscillation, and axial elastic compensation of the main sealing ring, the main sealing assembly can respond to changes in the radial position of the valve stem, changes in attitude, and changes in the axial dimensions of the sealing ring, thus forming a multi-degree-of-freedom adaptive compensation mechanism.

[0018] The main sealing assembly and the self-compensating assembly are integrated inside the cartridge housing, forming a relatively independent sealing function assembly. This facilitates overall configuration according to the installation space of the valve stuffing box, providing a structural basis for the modification of the sealing structure of existing valves and subsequent maintenance of the sealing components. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall longitudinal section of the modular cartridge-type composite valve stem sealing device provided in the embodiments of this application; Figure 2 The following is a partial structural schematic diagram of the main sealing module provided in the embodiments of this application, wherein (a) is a partial cross-sectional structural schematic diagram of the main sealing module along the valve stem axis, and (b) is a radial cross-sectional structural schematic diagram of the main sealing module along the direction perpendicular to the valve stem axis. Figure 3 The following is a partial structural schematic diagram of the quick-installation module provided in the embodiments of this application, wherein (a) is a partial cross-sectional schematic diagram of the quick-locking structure near the valve cover side, and (b) is a partial cross-sectional schematic diagram of the guide structure near the cartridge insertion side. Figure 4 This is a partial cross-sectional three-dimensional structural diagram of the modular cartridge-type composite valve stem sealing device provided in the embodiments of this application.

[0020] Explanation of reference numerals in the attached figures Detailed Implementation

[0021] To make the objectives and technical solutions of this application clearer and easier to understand, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0022] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more. In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] The technical solution of this application will be further described below with reference to the accompanying drawings. The following embodiments are used to illustrate the technical solution of this application, and are not intended to limit the scope of protection. Without departing from the technical concept of this application, the specific dimensions, materials, installation methods, and interconnection methods of each structure can be adaptively selected according to the valve type, working pressure, working temperature, and media characteristics.

[0024] The modular cartridge-type composite valve stem sealing device described in this application is mainly installed in the stuffing box area of ​​the valve, located between the valve stem 1 and the valve cover stuffing box 3, to limit the leakage of the working medium along the valve stem 1 to the atmosphere. In some embodiments, this application can be applied to industrial valves such as gate valves, ball valves, globe valves, and butterfly valves, and is suitable for valve stem reciprocating motion, rotary motion, or high-frequency cyclic motion conditions.

[0025] Example 1: like Figure 1 and Figure 2As shown, this embodiment provides a modular cartridge-type composite valve stem sealing device, including a cartridge housing module 110, a main sealing module 130, and a self-compensating module 150. The cartridge housing module 110 is installed inside the valve stuffing box and forms a mounting base for supporting the main sealing module 130 and the self-compensating module 150. The housing body 111 has a central through hole extending along the axial direction of the valve stem 1, through which the valve stem 1 passes.

[0026] The main sealing module 130 includes a main sealing ring 131, a floating support ring 132, an anti-rotation key 133, and a spherical guide surface 134. The main sealing ring 131 is sleeved on the outer periphery of the valve stem 1, and the inner circumferential sealing surface of the main sealing ring 131 forms a sealing contact with the outer circumferential surface of the valve stem 1. The floating support ring 132 is used to support the main sealing ring 131 and to allow the main sealing ring 131 to retain a small radial displacement degree of freedom relative to the cartridge housing module 110.

[0027] The floating support ring 132 supports the main sealing ring 131 and gives the main sealing ring 131 a predetermined range of radial freedom of movement relative to the cartridge housing module 110. When the valve stem 1 is radially offset relative to the central axis of the cartridge housing module 110, the main sealing ring 131 can float radially in the corresponding direction under the support of the floating support ring 132, so that the radial position of the main sealing ring 131 is adjusted according to the actual position of the valve stem 1.

[0028] The spherical guide surface 134 is located at the attitude adjustment position between the main sealing ring 131 and its supporting structure. When the axis of the valve stem 1 deviates at an angle relative to the axis of the cartridge housing module 110, the spherical guide surface 134 allows the main sealing ring 131 to swing at a corresponding angle through the spherical fit, so that the sealing surface of the main sealing ring 131 is adjusted with the tilting attitude of the valve stem 1.

[0029] The anti-rotation key 133 is used to limit the undesirable circumferential rotation of the main sealing ring 131 or the floating support ring 132 relative to the cartridge housing module 110. At the same time, the anti-rotation key 133 and the corresponding mating structure are provided with a space to allow the main sealing ring 131 to float radially, so as to avoid the anti-rotation structure restricting the radial adaptive movement of the main sealing ring 131.

[0030] When the valve stem 1 is radially offset relative to the central axis of the cartridge housing module 110 due to machining errors, installation errors, stress deformation, or long-term wear, the floating support ring 132 allows the main sealing ring 131 to float radially in the corresponding direction, so that the center position of the main sealing ring 131 can be adjusted according to the actual position of the valve stem 1, thereby reducing the situation where one side of the main sealing ring 131 is subjected to excessive compression while the other side has insufficient contact.

[0031] In some embodiments, a radial clearance is provided between the floating support ring 132 and the cartridge housing module 110 to allow the floating support ring 132 and the main sealing ring 131 to undergo radial displacement relative to the cartridge housing module 110 within the range defined by the radial clearance.

[0032] The spherical guide surface 134 is used to guide the attitude change of the main sealing ring 131, so that the main sealing ring 131 can generate angular swing when the axis of the valve stem 1 is tilted at a small angle relative to the axis of the cartridge housing module 110. The anti-rotation key 133 is used to limit the unwanted circumferential rotation of the main sealing module 130, while not hindering the radial floating and angular swing within the design allowable range.

[0033] The self-compensating module 150 includes a push ring 151, a disc spring assembly 152, a guide sleeve 153, and a limiting seat 154. The disc spring assembly 152 is arranged axially along the valve stem 1, and the push ring 151 is located between the disc spring assembly 152 and the main sealing module 130. The elastic force generated by the disc spring assembly 152 is transmitted to the main sealing ring 131 through the push ring 151, continuously applying a preload force along the valve stem 1 axial direction to the main sealing ring 131.

[0034] In the initial installation state, the disc spring assembly 152 is in a pre-compressed state. When the main sealing ring 131 wears due to friction, changes in thickness due to material creep, or changes in axial dimension due to changes in operating temperature during long-term operation, the disc spring assembly 152 drives the push ring 151 to move through the change in its own elastic deformation, thereby pushing the main sealing ring 131 to produce a corresponding compensating displacement along the valve stem 1 axially.

[0035] When the valve stem 1 only experiences radial displacement, the main sealing ring 131 primarily adjusts its radial position via the floating support ring 132. When the valve stem 1 experiences angular displacement, the main sealing ring 131 adjusts its posture using the spherical guide surface 134. When the main sealing ring 131 experiences wear or axial dimension changes, the disc spring assembly 152 provides axial compensation via the push ring 151. When these changes occur simultaneously, the main sealing ring 131 can simultaneously generate radial floating, angular oscillation, and axial compensation displacement, thereby maintaining a relatively uniform and stable sealing contact between the main sealing ring 131 and the valve stem 1.

[0036] Example 2: like Figure 1 and Figure 4 As shown, in one complete embodiment of this application, the modular sealed cartridge assembly 100 may include a cartridge housing module 110, a labyrinth decompression module 120, a main sealing module 130, a graphite backup module 140, a self-compensation module 150, a dustproof module 160, a monitoring module 170, and a quick-installation module 180. All or some of these modules can be selected for configuration according to actual operating conditions.

[0037] The cartridge housing module 110 may include a housing body 111, a compensation ring groove 112, a positioning shoulder 113, a gland contact surface 114, a quick-release locking groove 115, and a monitoring interface hole 116. The housing body 111 may be integrally formed into a thick-walled cylindrical structure, with a central through hole through which the valve stem 1 passes. The housing body 111 may be made of 316L stainless steel or Hastelloy.

[0038] A compensation ring groove 112 can be provided on the outer periphery of the cartridge housing module 110, and an elastic compensation ring 117 is provided within the compensation ring groove 112. The elastic compensation ring 117 can be a corrugated metal ring or an open elastic ring, and it compensates for dimensional differences, machining errors, wear and tear, and installation misalignment between the cartridge housing and the original valve stuffing box through its own radial elastic deformation. In one embodiment, the elastic compensation range can be ±0.5 to 1.0 mm.

[0039] In some embodiments, a labyrinth pressure-reducing module 120 is provided along the leakage path of the medium to the main sealing module 130. The labyrinth pressure-reducing module 120 includes a primary labyrinth ring 121, a secondary labyrinth ring 122, a tertiary labyrinth ring 123, and a limiting ring 124. The primary labyrinth ring 121, secondary labyrinth ring 122, and tertiary labyrinth ring 123 are arranged sequentially along the valve stem 1 to form a stepped labyrinth channel, and the limiting ring 124 is used to restrict the axial position of each labyrinth ring.

[0040] After passing through a multi-stage labyrinth structure, the flow path of the medium undergoes continuous changes in cross-sectional area or direction, thereby gradually reducing the pressure before reaching the main sealing area. The medium pressure can be expressed sequentially as P1→P2→P3→P4. As a parameterized example, when the inlet pressure is 25MPa, a gradual pressure reduction process of 25MPa→12MPa→5MPa→1MPa can be formed, after which the medium enters the main sealing area. The above pressure values ​​are examples; the actual pressure at each stage can be determined based on the medium properties, valve pressure rating, number of labyrinth stages, and flow clearance at each stage.

[0041] The main sealing ring 131 can be made of a composite material composed of highly filled PTFE, graphite, and carbon fiber. In some embodiments, a microporous ceramic coating can also be formed on the surface of the main sealing ring 131. Since the specific ceramic composition, thickness, porosity, and preparation process can be determined according to the material system and manufacturing conditions, this embodiment does not impose fixed limitations on the above parameters.

[0042] A graphite backup module 140 can be provided on the side of the main sealing module 130 facing the atmosphere. The graphite backup module 140 includes a flexible graphite ring 141, a first metal reinforcing ring 142, and a second metal reinforcing ring 143. The first metal reinforcing ring 142 and the second metal reinforcing ring 143 are used to improve the structural stability and load-bearing capacity of the flexible graphite ring 141. When the polymer main sealing material softens, melts, ages, or is damaged due to abnormal high temperature, resulting in a decrease in sealing capacity, the flexible graphite ring 141 can continue to form a backup seal around the valve stem 1.

[0043] In the self-compensation module 150, the limiting seat 154 is used to determine the installation position of the disc spring assembly 152, and the guide sleeve 153 is used to limit undesirable lateral displacement of the disc spring assembly 152 and the push ring 151 during loading. The disc spring assembly 152 can be in series, in parallel, or in a combination of series and parallel. In some embodiments, the disc spring assembly 152 can be made of a high-temperature alloy suitable for high-temperature environments.

[0044] The axial force transmission path of the self-compensation module 150 can be represented as follows: the valve cover 2 applies an axial installation load to the self-compensation module 150, the limit seat 154 axially limits the disc spring assembly 152, so that the disc spring assembly 152 forms a pre-compressed state; the elastic force of the disc spring assembly 152 is transmitted to the main sealing module 130 through the push ring 151 to continuously provide axial pre-tightening effect to the main sealing ring 131.

[0045] The push ring 151 has a force transmission portion extending toward the main sealing module 130, which directly transmits the axial load of the disc spring assembly 152 to the main sealing module 130.

[0046] The disc spring assembly 152 stores elastic potential energy under compression, and continuously applies preload to the main sealing module 130 via the push ring 151. In one embodiment, the working stroke of the disc spring can be 0.2 to 0.5 mm.

[0047] In some embodiments of this application, the combined sealing effect acting on the sealing area can be represented by the following engineering relationship: F 总密封 = F 碟簧 + P·A 有效 + F 迷宫阻力 Among them, F 总密封 Indicates comprehensive sealing function; F 碟簧 Indicates the self-compensating preload provided by disc spring assembly 152; P represents the medium pressure acting on the corresponding effective pressure-bearing area; A 有效 P·A represents the effective pressure-bearing area corresponding to the medium pressure. 有效 F represents the pressure exerted by the medium pressure on the effective pressure-bearing area; 迷宫阻力This represents the equivalent action quantity corresponding to the resistance effect formed when the medium passes through the stepped labyrinth structure.

[0048] The above relationship embodies a passive adaptive sealing effect, which does not require an electronic controller to perform active feedback control. When the sealing material wears or undergoes thermal deformation, the stroke of the disc spring assembly 152 changes automatically; when the medium pressure changes, the medium pressure action changes accordingly. The labyrinth pressure reducing module 120 then implements graded blocking of the medium pressure path.

[0049] The dustproof module 160 includes a primary dustproof lip 161, a secondary dustproof lip 162, a scraper ring 163, and an anti-rotation key 164. The primary dustproof lip 161 and the secondary dustproof lip 162 are sequentially arranged along the axial direction of the valve stem 1 on the atmospheric side of the cartridge, used to restrict external dust and particulate matter from entering the cartridge as the valve stem 1 moves. The scraper ring 163 is arranged around the valve stem 1; when the valve stem 1 reciprocates or rotates, the scraper ring 163 removes dust and particulate matter adhering to the exposed surface of the valve stem 1, reducing the possibility of external contaminants entering the main sealing area. The scraper ring 163 can be made of SiC or alumina ceramic material.

[0050] When external dust or particulate matter adheres to the surface of the exposed section of valve stem 1, the primary dustproof lip 161, the secondary dustproof lip 162, and the scraper ring 163 block or remove the contaminants to reduce the amount of external particulate matter entering the cartridge as the valve stem 1 moves.

[0051] Depending on actual needs, pressure balancing holes can also be provided to reduce the unfavorable pressure difference formed on both sides of the dustproof module 160. The pressure balancing holes can be in the form of micro-holes, with a diameter of, for example, 0.1–0.3 mm. This size is an optional engineering parameter.

[0052] like Figure 3 and Figure 4 As shown, the quick-installation module 180 includes a guide cone 181, a locating pin 182, a snap-fit ​​groove 183, and a mis-proof mark 184. The guide cone 181 is located at the front end of the cartridge assembly 100 along the insertion direction of the stuffing box, and is used for guiding and centering the cartridge assembly 100 when it is inserted into the stuffing box. The locating pin 182 and the snap-fit ​​groove 183 are located on the side of the cartridge assembly 100 near the valve cover 2. The locating pin 182 defines the installation position of the cartridge assembly 100, and the snap-fit ​​groove 183 engages with a locking structure on one side of the valve cover 2. The mis-proof mark 184 is located in an observable position during installation to indicate the correct installation direction of the cartridge assembly 100.

[0053] The monitoring module 170 is disposed radially outside the cartridge housing module 110 and corresponds to the monitoring interface hole 116 on the housing body 111. The monitoring module 170 is a side-mounted monitoring component extending axially along the valve stem 1. In the illustrated embodiment, the monitoring module 170 is located on the right side of the cartridge housing module 110.

[0054] The displacement scale rod 171 is correspondingly set with the observation window 172 facing the radial outer side of the cartridge housing module 110, so that the operator can directly observe the status of the displacement scale rod 171 from the outside of the device.

[0055] In the illustrated embodiment, the observation window 172 is a longitudinally elongated partial window, and the displacement scale rod 171 is arranged along the long axis of the observation window 172. The pressure sensor 173 is located above the observation window 172 or near the monitoring interface, while the temperature sensor 174 and the wiring interface 175 can be located below the observation window 172 or in the adjacent area. The above-mentioned vertical positions are one implementation method that facilitates installation and reading, and can be adjusted according to the space of the housing interface.

[0056] The displacement scale rod 171 is configured to correspond to the displacement state of the self-compensation module 150. The observation window 172 is used to display the position change of the displacement scale rod 171 to characterize the compression state or residual compensation state of the disc spring assembly 152. In some embodiments, the observation window 172 can be configured with a scale area or state area to characterize the compression state of the disc spring assembly 152. The specific graduations of the scale area and the division of different state areas can be calibrated according to the rated stroke, allowable residual compensation amount, and maintenance strategy of the disc spring assembly 152. The specific threshold can be determined according to the rated stroke, allowable residual compensation amount, and maintenance strategy of the disc spring. The electronic monitoring signal can be transmitted using a 4-20mA output, RS485 communication, or wireless method.

[0057] The displacement scale rod 171 forms a displacement linkage relationship with the limiting seat 154 or the push ring 151. When the compression of the disc spring assembly 152 changes, the axial position of the limiting seat 154 or the push ring 151 changes accordingly, and drives the scale position of the displacement scale rod 171 relative to the observation window 172 to change. Thus, the position of the displacement scale rod 171 represents the compression state of the disc spring assembly 152.

[0058] The pressure sensor 173 is connected to a predetermined pressure monitoring area inside the cartridge through the monitoring interface hole 116, and is used to detect the medium pressure in the predetermined pressure monitoring area.

[0059] During installation, the original valve cover 2 can be opened or removed first, the original packing can be taken out and the inner wall of the stuffing box and the surface of the valve stem 1 can be cleaned; then the guide cone 181 can be inserted into the corresponding position, and the guide structure can be used to gradually align the cartridge assembly with the valve stem 1 and the stuffing box. Then the pre-assembled modular sealing cartridge assembly 100 can be inserted into the stuffing box along the valve stem 1 axially.

[0060] After the cartridge is installed in place, it is axially fixed by the original valve cover 2 or the quick-locking flange and the cover bolts are tightened. As the valve cover 2 is gradually tightened, the limit seat 154 pushes the disc spring assembly 152 to form a predetermined compression amount, and the disc spring assembly 152 then applies axial preload to the main sealing module 130 through the push ring 151.

[0061] The complete installation process can be represented as follows: Remove the old packing → Clean the stuffing box → Insert the guide cone 181 → Insert the cartridge assembly 100 → Tighten the valve cover 2 → Complete the installation.

[0062] After the valve is put into operation, in the embodiment with the labyrinth pressure reducing module 120, the medium first enters the labyrinth area, and after being depressurized step by step through the first to third level labyrinth structure, it reaches the main sealing module 130. The main sealing ring 131 forms a contact seal with the valve stem 1, and the disc spring assembly 152 continuously applies axial preload to the main sealing ring 131 through the push ring 151.

[0063] When the valve stem 1 is radially offset, the floating support ring 132 causes the main sealing ring 131 to move radially accordingly; when the axis of the valve stem 1 is angularly offset, the spherical guide surface 134 causes the main sealing ring 131 to swing angularly accordingly; when the sealing surface wears due to long-term friction, the disc spring assembly 152 automatically releases part of the compression stroke, pushing the main sealing ring 131 to move axially to compensate for the wear.

[0064] When the sealing capacity of the main sealing ring 131 decreases due to abnormal high temperature, aging or damage, the flexible graphite ring 141 located behind it continues to provide redundant sealing; when dust, coking, crystals or sand particles carried on the surface of the valve stem 1 move to the dustproof area, the primary dustproof lip 161, the secondary dustproof lip 162 and the scraper ring 163 block and remove the attached substances.

[0065] During maintenance, the position of the displacement scale rod 171 can be directly read from the right side of the device through the observation window 172 to determine the current compression state of the disc spring assembly 152. When the electronic monitoring module is set up, the data of the pressure sensor 173 and the temperature sensor 174 can be read, and the operating parameters can be transmitted to the external monitoring device through the wiring interface 175.

[0066] When the displacement scale indicates insufficient remaining compensation stroke or monitoring parameters indicate that the sealing condition requires maintenance, the quick-locking structure can be released and the cartridge assembly removed. In the modular maintenance method, only the internal sealing core or failed sealing components can be replaced, while the cartridge housing module 110 that meets the usage requirements can continue to be used.

[0067] In one embodiment of this application, when the above-mentioned device is used to implement sealing force compensation, the cartridge housing module 110 is first installed in the valve stuffing box, so that the valve stem 1 passes through the housing body 111 and the main sealing ring 131, and the disc spring assembly 152 obtains initial compression through the valve cover 2.

[0068] After installation, the main sealing ring 131 forms a sealing contact around the valve stem 1. When the valve stem 1 experiences radial displacement, the floating support ring 132 allows the main sealing ring 131 to move radially relative to the cartridge housing module 110, thereby readjusting the main sealing ring 131 to the current position of the valve stem 1.

[0069] When the valve stem 1 deviates at an angle, the spherical guide surface 134 allows the main sealing ring 131 to swing at an angle around the corresponding direction, so that the posture of the sealing surface of the main sealing ring 131 is adjusted with the tilt direction of the valve stem 1.

[0070] Meanwhile, the disc spring assembly 152 continuously provides axial preload to the main sealing ring 131 through the push ring 151. When the main sealing ring 131 undergoes axial dimension changes due to operational wear, material creep, or thermal deformation, the disc spring assembly 152 drives the push ring 151 to move through its own elastic displacement, and the push ring 151 further pushes the main sealing ring 131 to perform axial compensation.

[0071] Radial position compensation, angular attitude compensation, and axial wear compensation can occur simultaneously according to the operating state of valve stem 1, so that the changes of main sealing ring 131 in multiple directions can be adapted to the actual position of valve stem 1 and the state of sealing material. Optional parameters and material requirements are shown in Table 1.

[0072] Table 1

[0073] The parameters mentioned above are optional for specific applications and do not necessarily limit other implementation methods. The actual achievable operating temperature, leakage rate, and service life are related to the main sealing material, graphite backup material, disc spring material, valve stem surface condition, media type, movement frequency, and test conditions. For high-temperature conditions, the graphite backup module 140 can provide redundant sealing under high-temperature conditions, while the actual allowable operating temperature of the polymer main sealing material should be determined based on the selected composite material system.

[0074] In some embodiments, the cartridge housing can be made of 316L stainless steel, while Hastelloy can be used in more corrosive environments; the disc spring assembly 152 can be made of high-temperature alloy materials, such as Inconel 718 or 17-7PH; the scraper ring 163 can be made of SiC or alumina ceramic; the dustproof sealing structure can use appropriate sealing materials such as FKM or FFKM, depending on the medium and temperature. The selection of different materials is to adapt to high temperature, high pressure, corrosive media, particulate media, and reciprocating or rotating valve stem conditions, and it is not required that all embodiments use all of the above materials simultaneously.

[0075] Taking an inlet medium pressure of 25 MPa as an example, when using a three-stage labyrinth pressure-reducing structure, the medium can be depressurized step by step according to the following pressure path after entering the labyrinth area: 25 MPa → 12 MPa → 5 MPa → 1 MPa In some implementations, for ease of engineering analysis, the following equivalent relationships can be used to characterize the disc spring preload, the medium pressure, and the impediment effect of the labyrinth structure on the flow of the leaking medium: F 总密封 = F 碟簧 + P·A 有效 + F 迷宫阻力 It should be noted that F 迷宫阻力 The stepped labyrinth structure is used in engineering to equivalently characterize the flow resistance and pressure attenuation that inhibits the leakage trend of the medium. It does not imply that the labyrinth structure necessarily generates an independent axial mechanical load in the same direction as the disc spring preload. The stepped labyrinth structure primarily reduces the effective medium pressure acting on the main sealing area by gradually decreasing the pressure of the medium along the leakage path.

[0076] As operating time increases, the main sealing surface wears down. The disc spring assembly 152 releases part of its pre-compression stroke, driving the push ring 151 to continue pushing the main sealing ring 131, thereby compensating for the axial wear of the sealing surface. This working process can be represented as: medium enters the labyrinth region → multi-stage labyrinth decompression → main seal forms a contact seal → long-term wear of the sealing surface → disc spring automatically extends to compensate for wear.

[0077] The above content provides a further detailed description of this application and should not be construed as limiting the specific implementation methods of this application to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of this application, and all such deductions or substitutions should be considered as falling within the scope of protection defined by the submitted claims.

Claims

1. A modular cartridge-type composite valve stem sealing device, characterized in that: It includes a cartridge housing for installation in a valve stuffing box, and a main sealing assembly and a self-compensating assembly disposed within the cartridge housing and fitted around the valve stem. The cartridge housing has a central through-hole through which the valve stem passes. The main sealing assembly includes a main sealing ring, a floating support ring for supporting the main sealing ring, and a spherical guide surface for guiding the attitude of the main sealing ring. The floating support ring allows the main sealing ring to float radially relative to the cartridge housing, so that the main sealing ring adjusts its sealing position with the radial offset of the valve stem. The spherical guide surface is used to guide the attitude of the valve stem. When the angle deviates, the main sealing ring is guided to swing at an angle, so that the main sealing ring adjusts its sealing posture according to the posture change of the valve stem. The self-compensating assembly includes a disc spring assembly and a push ring disposed between the disc spring assembly and the main sealing assembly. The disc spring assembly continuously applies a preload along the valve stem axis to the main sealing ring through the push ring, and drives the main sealing ring to generate an axial compensation displacement when the main sealing ring wears or changes its axial position, so that the radial floating, angle swing and axial compensation displacement of the main sealing ring cooperate with each other to maintain the sealing contact between the main sealing ring and the valve stem.

2. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The cartridge housing is also provided with a labyrinth pressure reducing assembly. The labyrinth pressure reducing assembly is disposed between the medium side and the main sealing assembly along the leakage path of the medium flowing towards the main sealing assembly. The labyrinth pressure reducing assembly has multiple pressure reducing sections connected sequentially along the leakage path, so that the medium is pressure reduced step by step through the multiple pressure reducing sections before reaching the main sealing ring.

3. The modular cartridge-type composite valve stem sealing device according to claim 2, characterized in that, The labyrinth decompression assembly includes a primary labyrinth ring, a secondary labyrinth ring, a tertiary labyrinth ring, and a limiting ring. The primary, secondary, and tertiary labyrinth rings are arranged along the axial direction of the valve stem and together form a stepped labyrinth channel with multiple decompression sections. The limiting ring is used to axially limit the primary, secondary, and tertiary labyrinth rings.

4. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The cartridge housing also includes a graphite backup assembly located on the side of the main sealing assembly facing the atmosphere. The graphite backup assembly includes a flexible graphite ring and a metal reinforcing ring disposed on the flexible graphite ring to form a redundant seal when the sealing capacity of the main sealing ring is reduced due to high temperature, aging or damage.

5. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The main sealing ring is made of a composite material containing highly filled polytetrafluoroethylene, graphite and carbon fiber, and the surface of the main sealing ring is provided with a microporous ceramic coating.

6. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The outer periphery of the cartridge housing is provided with a compensation ring groove, and an elastic compensation ring is provided in the compensation ring groove. The elastic compensation ring is a corrugated metal ring or an open elastic ring, which is used to compensate for the dimensional deviation between the cartridge housing and the valve stuffing box, stuffing box wear, or installation misalignment through its own elastic deformation.

7. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The cartridge housing is also provided with a dustproof and dirt-scraping assembly, which includes a primary dustproof lip, a secondary dustproof lip, and a dirt-scraping ring arranged along the valve stem axial direction. The dirt-scraping ring is made of silicon carbide or alumina ceramic material.

8. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The cartridge housing is provided with a quick-installation assembly, which includes a guide cone, a positioning pin, a snap-fit ​​groove, and a mis-proof mark. The guide cone is used to guide the cartridge housing into the valve stuffing box, the positioning pin is used to define the installation position of the cartridge housing, the snap-fit ​​groove is used to cooperate with the locking structure on the valve gland side, and the mis-proof mark is used to indicate the installation direction of the cartridge housing.

9. The modular cartridge-type composite valve stem sealing device according to claim 1, characterized in that, The cartridge housing is also provided with a monitoring component, which includes a displacement scale rod, an observation window, a pressure sensor, a temperature sensor, and a wiring interface. The displacement scale rod is correspondingly set with the self-compensation component and is used to characterize the compression state of the disc spring assembly. The observation window is used to display the position of the displacement scale rod. The pressure sensor and the temperature sensor are used to detect the pressure parameters and temperature parameters of the sealing device, respectively.

10. A sealing force compensation method implemented using the modular cartridge-type composite valve stem sealing device according to any one of claims 1 to 9, characterized in that, include: The cartridge housing is installed inside the valve stuffing box, and the valve stem passes through the cartridge housing and the main sealing ring; The main sealing ring forms a sealing contact with the valve stem. When the valve stem deviates radially, the floating support ring causes the main sealing ring to float radially relative to the cartridge housing, thereby adjusting the radial sealing position of the main sealing ring relative to the valve stem. When the valve stem deviates angularly, the spherical guide surface guides the main sealing ring to swing angularly, thereby adjusting the sealing posture of the main sealing ring relative to the valve stem. The disc spring assembly continuously applies a preload along the valve stem axis to the main sealing ring via the push ring. When the main sealing ring experiences wear, material creep, or axial position change, the elastic displacement of the disc spring assembly drives the push ring and the main sealing ring to generate compensating displacement along the valve stem axis. This allows the radial floating, angular oscillation, and axial compensating displacement of the main sealing ring to cooperate with each other to maintain the sealing contact between the main sealing ring and the valve stem.

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