Anti-eccentricity double-floating dry-running seal with self-cooling

Abstract

The application relates to a self-cooled anti-yaw double-floating dry-running seal, which comprises a shaft sleeve, a movable ring and a static ring, the movable ring is arranged outside the shaft sleeve, and the movable ring and the shaft sleeve are driven through a yoke; the static ring is arranged in a cavity of a static ring seat; a first elastic member is arranged on the side of the movable ring away from the static ring, so that the movable ring is axially floated relative to the shaft sleeve; at least one second elastic member is arranged in the cavity of the static ring seat, the second elastic member is connected with a first push ring, the first push ring is tightly attached to the side of the static ring away from the movable ring through a fourth O-shaped ring, so that the first push ring and the fourth O-shaped ring are always floated with the static ring; the side of the static ring away from the movable ring is subjected to static elastic force and first medium pressure applied by the second elastic member, and the side of the movable ring away from the static ring is subjected to dynamic elastic force and second medium pressure applied by the first elastic member; in the process that the movable ring and the static ring are converted from an unbalanced state to an equilibrium state, the end faces of the movable ring and the static ring can always contact and keep close, and bidirectional floating in the axial direction is realized.

Description

Technical Field

[0001] This invention relates to the field of dry-run sealing technology, and more particularly to a self-cooling, anti-sway double floating dry-run seal. Background Technology

[0002] Dry-run seals are a common type of seal, characterized by their simple structure and lack of the need for auxiliary systems. Common dry-run seal diagrams are shown below. Figure 20 As shown, the moving ring and the stationary ring are in contact and running. The moving ring has a spring on its back, which allows it to float up and down with the shaft. The stationary ring is pressed down by the pressure plate 36 and fixed on the connecting plate.

[0003] Existing dry-run seals have two drawbacks: First, it can only be applied to low-speed equipment: because the sealing end face is in contact with the machine during operation, and there are no cooling or lubrication measures for the seal, the service life of the seal is improved solely by the good self-lubricating properties and high thermal conductivity of the sealing ring material. However, when the seal speed is too high, the sealing end face will suffer severe wear due to excessive heat accumulation, and the accumulation of wear material on the end face will further aggravate the wear of the sealing end face. Table 1 shows the relationship between the linear speed of the seal and the amount of wear under normal dry operation, based on a certain parameter tested in the factory.

[0004] Table 1: Relationship between seal linear velocity and wear during normal dry operation

[0005] As shown in Table 1, the wear of conventional dry-running seals increases exponentially with increasing linear velocity. Therefore, conventional dry-running seals can only be used in low-speed equipment, such as reactors and agitators. Dry-running seals are rarely seen in high-speed equipment such as pumps, centrifuges, and high-speed agitators.

[0006] Second: The sealing and anti-sway capability is poor. For example... Figure 20 As shown, the stationary ring 13, pressure plate 36, and tooling connecting plate 26 are connected as a whole by screws. The pressure plate 36 completely presses down the stationary ring 13, preventing relative movement between the stationary ring 13 and the tooling connecting plate 26. The tooling connecting plate 26 is assembled with the equipment cavity by connecting screws 37, as shown. Figure 21As shown, the main shaft 300 is vertically positioned, and the main shaft centerline 301 is also vertically positioned. The sealing ring and other components are fixed to the main shaft 300 by set screws. Under the action of dynamic spring force and the pressure of the second medium, theoretically, the main shaft / rotating ring centerline 303 is the same as the main shaft centerline 301. When the equipment cavity is not perpendicular to the main shaft 300, assuming the angle between the equipment cavity centerline and the main shaft centerline 301 is 1°, since the tooling connecting plate 26 is directly fixed to the cavity and the stationary ring 13 is connected to the tooling connecting plate 26 by screws, theoretically, the angle between the cavity / stationary ring centerline 302 and the main shaft centerline 301 is also 1°. This results in an angle between the stationary ring end face and the rotating ring end face, such as... Figure 22 As shown, the contact between the rotating ring end face and the stationary ring is not uniform across the entire surface, resulting in uneven contact and making the seal prone to uneven wear, thus affecting its service life. Furthermore, the low-speed equipment currently used for dry-running seals generally suffers from poor precision, which negatively impacts the long-term use of these seals.

[0007] CN105889515A discloses a contact-type dry-run seal, including a sealing structure disposed between a flange, an end cover, and a housing. A bushing is disposed on a rotating shaft. The sealing structure includes a stationary ring seat fixedly mounted on the housing, a spring seat fixedly fitted on the bushing, and sealing pairs and elastic components symmetrically disposed on both sides of the spring seat. The sealing pairs include a rotating ring and a stationary ring that mate through sealing end faces. The rotating rings are both fitted on the spring seats. The elastic components act on the end faces of the rotating rings to ensure a tight fit between the sealing end faces of the rotating rings and the stationary rings. The two stationary rings are fixedly mounted on the stationary ring seat and the flange, respectively. A bearing is disposed between the stationary ring seat and the bushing. This technical solution does not introduce an active cooling or lubrication structure, nor does it mention the optimization of the thermal stability or self-lubricating performance of the sealing material under high-speed friction. Therefore, although this structure may improve the service life of the seal to some extent, it still essentially relies on the self-lubricating and thermal conductivity of the material to maintain operation, and does not fundamentally solve the problems of heat accumulation and accelerated wear under high speed.

[0008] Therefore, this invention proposes a high-speed dry-run seal that can adapt to environments with poor equipment precision, enabling it to be used for a long period in low-speed stirring tanks with poor precision, or in equipment with higher speeds (≤4000rpm), without the need for auxiliary air sources and sealing fluids. Summary of the Invention

[0009] Existing dry-running seals have two significant technical limitations. First, their applicability is limited to low-speed operating environments. These seal structures employ an end-face contact design, lacking an active cooling and lubrication system, relying solely on the self-lubricating properties and thermal conductivity of the sealing material to maintain operational stability. When the equipment speed exceeds a critical value, the heat generated at the friction interface accelerates material wear, and the accumulation of wear particles on the contact surface creates a vicious cycle, leading to a rapid decline in sealing performance. Experimental data shows that when the linear velocity increases from 0.5 m / s to 8 m / s, the wear amount exhibits an exponential growth trend, surging from 2.3 μm to 863.5 μm. This performance degradation characteristic determines that this technology is mainly suitable for operating scenarios with speeds below 8 m / s, such as reactors and agitators, and is difficult to meet the sealing requirements of high-speed rotating machinery such as pumps and centrifuges.

[0010] Secondly, existing dry-run seals have a significant deficiency in adapting to equipment installation errors. Their fixing structure uses a rigid connection, with the stationary ring assembly forming a fixing unit via a pressure plate and a tooling connection disc. This fixing unit is then rigidly connected to the equipment cavity. When there is a slight angular deviation (e.g., 1°) between the spindle and the cavity, this error is directly transmitted to the sealing end face, causing the contact surfaces of the rotating and stationary rings to tilt at the same angle. This non-uniform contact state leads to localized stress concentration, resulting in uneven wear distribution on the end face and thus shortening the service life of the sealing assembly. It is worth noting that the low-speed equipment where this technology is mainly applied generally suffers from low manufacturing precision. The combined effect of this structural defect and operating conditions further exacerbates the instability of the sealing performance.

[0011] To address the shortcomings of existing technologies, this invention provides a self-cooling, anti-sway, double-floating dry-run seal, comprising a bushing, a rotating ring, and a stationary ring. The rotating ring is disposed outside the bushing, and the rotating ring and bushing are connected by a fork transmission. The stationary ring is disposed within a cavity of a stationary ring seat. A first elastic element is disposed on the side of the rotating ring facing away from the stationary ring, allowing the rotating ring to float axially relative to the bushing. At least one second elastic element is disposed within the cavity of the stationary ring seat, and the second elastic element is connected to a first push ring. The first push ring is tightly attached to the side of the stationary ring facing away from the rotating ring via a fourth O-ring, ensuring that the first push ring and the fourth O-ring always float with the stationary ring. The side of the stationary ring facing away from the rotating ring is subjected to a static elastic force and a first medium pressure applied by the second elastic element, while the side of the rotating ring facing away from the stationary ring is subjected to a dynamic elastic force and a second medium pressure applied by the first elastic element. Under the axial dynamic action of the static elastic force, the first medium pressure, the dynamic elastic force, and the second medium pressure, during the transition from an unbalanced state to a balanced state between the rotating ring and the stationary ring, the sealing end faces of the rotating ring and the stationary ring can always contact and remain in contact, achieving bidirectional floating in the axial direction.

[0012] In this invention, the rotating ring and stationary ring are subjected to the combined effects of dynamic and static spring forces from the spring, as well as the pressures of the first and second media on both sides. When the seal is in operation, these axial forces dynamically change, causing the rotating and stationary rings to gradually transition from an unbalanced state to a balanced state, ensuring that their sealing end faces are always in contact and remain in contact, while simultaneously achieving bidirectional axial floating. This design significantly improves the sealing surface's adaptability to axial displacement and pressure fluctuations, especially during start-up and shutdown phases or under conditions of sudden pressure changes, maintaining the stability of the end face contact force and avoiding the risk of leakage due to instantaneous separation. This alleviates the end face detachment problem caused by rigid fixation in traditional structures and partially solves the defect of low-speed seals being unable to cope with fluctuations in operating conditions.

[0013] According to a preferred embodiment, the steps in the cavities of the stationary ring and the stationary ring seat are concentric; there is a first gap and a second gap between the stationary ring and the stationary ring seat, so that when the stationary ring floats along the axial direction of the rotation axis, the stationary ring seat will not come into direct contact with the stationary ring and will not interfere with the floating of the stationary ring.

[0014] The design of the first and second gaps ensures that the stationary ring will not directly contact the stationary ring seat during axial floating, avoiding structural interference and guaranteeing the reliability of the stationary ring's free floating. This technology effectively reduces the additional constraint stress caused by assembly errors or thermal deformation, enhances the sealing assembly's tolerance to minor deformations, and thus mitigates the off-center load effect transmitted to the sealing end face due to installation deviations, improving the stability and lifespan of the seal operation.

[0015] According to a preferred embodiment, the moving ring and the bushing are concentric; there is a third gap between the moving ring and the bushing, so that when the moving ring floats axially, the moving ring will not come into direct contact with the bushing and will not interfere with the floating of the moving ring.

[0016] This third clearance allows the rotating ring to float axially without physical obstruction from the bushing structure, achieving interference-free floating. This design not only ensures the flexibility of the rotating ring's axial movement but also reduces additional resistance and localized wear caused by friction on the mating surfaces, improves the rotating ring's sensitivity to pressure changes, and helps maintain consistent end-face contact, especially under conditions of vibration or axial movement, ensuring good sealing performance.

[0017] According to a preferred embodiment, a plurality of unidirectional microgrooves are provided on the end face of the rotating ring that cooperates with the stationary ring. The small diameter of the unidirectional microgrooves is smaller than the inner diameter of the end face of the stationary ring, so as to ensure that the gas inside the rotating ring can enter the unidirectional microgrooves. The outer diameter of the unidirectional microgrooves is smaller than the outer diameter of the end face of the stationary ring, so as to ensure that the gas inside the rotating ring cannot directly enter the outside of the rotating ring through the unidirectional microgrooves.

[0018] This structure generates a hydrodynamic pressure effect when the rotating ring end face rotates, producing a directional gas film support force that partially offsets the contact pressure on the rotating ring end face, reducing actual contact stress and frictional power consumption. This technology helps reduce the direct contact area between the rotating and stationary ring end faces, suppressing temperature rise and wear under dry friction conditions. Especially during medium- and high-speed operation, it can significantly delay material loss, thereby alleviating the problem of rapid wear in traditional dry-running seals after speed increases.

[0019] According to a preferred embodiment, a plurality of bidirectional microgrooves are provided on the end face of the rotating ring that cooperates with the stationary ring. The outer diameter of the bidirectional microgrooves is smaller than the outer diameter of the end face of the stationary ring, and the inner diameter of the bidirectional microgrooves is smaller than the inner diameter of the end face of the stationary ring, so as to ensure that the gas inside the rotating ring cannot directly enter the outside of the rotating ring through the bidirectional microgrooves.

[0020] Bidirectional microgrooves can form symmetrical hydrodynamic support between the end faces of the rotating ring, enhancing the rigidity and stability of the gas film and further optimizing the lubrication state between the end faces of the rotating and stationary rings. Compared to unidirectional grooves, bidirectional microgrooves are more suitable for bidirectional rotation or frequent start-stop conditions, improving the adaptability of the seal under complex motion conditions, helping to maintain low friction and low wear operation of the end faces, and extending service life.

[0021] According to a preferred embodiment, the outer side of the bushing is provided with uniformly distributed spiral grooves. When the bushing rotates with the rotating shaft (21), the spiral grooves will drive the gas in the spiral grooves to flow along the groove direction, transporting the high-temperature gas on the moving ring side to the atmospheric side through the spiral grooves. A slight negative pressure is formed on the moving ring side, and the room-temperature gas on the atmospheric side flows to the moving ring side through the gap between the stationary ring seat and the bushing, thereby forming a circulation. The high-temperature gas on the moving ring side is continuously transported to the atmospheric side, and the room-temperature gas on the atmospheric side replenishes the moving ring side and exchanges heat with the moving ring and stationary ring, carrying away the heat generated by the wear of the moving ring and stationary ring. With this structure, the self-cooling mechanism formed does not require an external cooling source and can continuously carry away the heat from the sealing end face, effectively controlling the temperature of the friction interface.

[0022] According to a preferred embodiment, the outer side of the bushing is provided with several bidirectional grooves. When the bushing rotates with the rotating shaft, the bidirectional grooves drive the gas inside the bushing to rotate together, accelerating the flow of gas on the moving ring side and the atmospheric side. This allows for more thorough heat exchange between the high-temperature gas on the moving ring side and the ambient temperature gas on the atmospheric side, thus removing the heat generated by wear on the end faces of the moving and stationary rings. This structure enhances the heat exchange process within the sealing cavity, allowing for more thorough mixing of the high-temperature gas and the external cool air, thereby improving the overall heat dissipation capacity. Combined with the air-guiding effect of the spiral grooves, the bidirectional grooves further improve the stability and response speed of the cooling system, especially under high-speed or continuous operation conditions, effectively preventing seal failure caused by localized overheating.

[0023] According to a preferred embodiment, the device further includes a drive ring, which is connected to and fixed on the shaft sleeve, allowing it to rotate with the shaft. The drive ring has several arc-shaped grooves on its drive-seal side facing the seal. These arc-shaped grooves extend outward from the inner diameter of the drive ring along the radial direction of the shaft, and their cross-sectional area gradually increases with outward extension. A straight groove is provided in the inner hole of the drive ring, milling through the inner hole and communicating with the arc-shaped grooves. When the drive ring rotates with the shaft, the arc-shaped grooves compress the ambient temperature gas in the atmosphere outside the drive ring and transport it to the inner diameter of the drive ring. A portion of the ambient temperature gas flows through the straight groove to the atmosphere on the side of the drive ring away from the seal; another portion flows to the sealing side of the rotating and stationary rings, interacting with the spiral groove on the outer side of the shaft sleeve, carrying away the high-temperature gas at the sealing end face, allowing the high-temperature gas to flow from the straight groove to the atmosphere. The active air intake mechanism formed in this way significantly enhances the flow rate and pressure of the cooling airflow, improves the heat exchange efficiency, and can still maintain effective cooling of the sealing end face, especially under high sealing pressure or high temperature environment conditions, further expanding the applicable range of the seal.

[0024] According to a preferred embodiment, a bushing step is provided on the outer side of the bushing to limit the displacement of the moving ring towards the atmosphere. A moving ring seat is provided on the side of the moving ring facing the medium, and the moving ring seat is restricted from displacement towards the medium by a first retaining ring. A cylindrical pin is provided on the outer side of the bushing, with one end of the cylindrical pin fixed on the bushing and the other end extending into the pin groove of the moving ring, so that the moving ring can rotate together with the bushing.

[0025] This multi-limit and transmission structure ensures that the moving ring maintains both axial freedom and circumferential synchronization during the floating process, avoiding transmission failure or jamming caused by floating, and improving the reliability and safety of the seal operation.

[0026] According to a preferred embodiment, an O-ring is provided in the groove at the outer diameter of the stationary ring made of a hard material, so that the first medium pressure acts only on the side of the stationary ring facing the medium; the rotating ring made of a soft material is disposed in the rotating ring seat, which is fixed to the outside of the bushing by a set screw, and a second push ring and a fifth O-ring are provided between the rotating ring and the rotating ring seat. The material and structural matching design of the present invention takes into account both wear resistance and compliance. The hard stationary ring provides a stable sealing surface, while the soft rotating ring has better floating response capability and anti-shake adaptability. The two work together to maintain relatively parallel contact of the end faces even when there is a small shaft misalignment angle (e.g., 1°), reduce local stress concentration, improve the uniformity of wear distribution, and thus effectively alleviate the problem of early failure caused by installation errors. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the first type of self-cooling anti-sway double floating dry-running seal provided by the present invention; Figure 2 This is a schematic diagram of the floating sealing stationary ring provided by the present invention; Figure 3 This is a schematic diagram of the floating sealing ring provided by the present invention; Figure 4 This is a schematic diagram of the axial force on the sealing dynamic and static rings provided by the present invention; Figure 5 This is a schematic diagram of the normal clearance between the stationary ring and the stationary ring seat provided by the present invention; Figure 6 This is a schematic diagram of the stationary ring seat deflection provided by the present invention; Figure 7 This is a schematic diagram of the normal clearance between the rotating ring and the bushing provided by the present invention; Figure 8 This is a schematic diagram of the bushing misalignment provided by the present invention; Figure 9 This is a schematic diagram of the unidirectional microgroove on the end face of the moving ring provided by the present invention; Figure 10 This is a schematic diagram of the bidirectional microgroove on the end face of the moving ring provided by the present invention; Figure 11 This is a schematic diagram of the spiral groove on the bushing provided by the present invention; Figure 12 This is a schematic diagram of the bidirectional groove on the bushing provided by the present invention; Figure 13 This is a planar schematic diagram of the arc-shaped groove of the drive ring provided by the present invention; Figure 14 This is a three-dimensional schematic diagram of the arc-shaped groove of the drive ring provided by the present invention; Figure 15 This is a schematic diagram of the bidirectional groove of the drive ring provided by the present invention; Figure 16 This is a schematic diagram of gas flow at the sealing position provided by the present invention; Figure 17 This is a cross-sectional view of the second type of self-cooling anti-sway double floating dry-running seal provided by the present invention; Figure 18 This is a cross-sectional view of the third type of self-cooling anti-sway double floating dry operation seal provided by the present invention. Figure 19 This is a schematic diagram of the experimental fixture provided by the present invention; Figure 20 This is a cross-sectional view of the existing dry-run seal provided by the present invention; Figure 21 This is a schematic diagram of the angle between the center line of the cavity / stationary ring and the center line of the main shaft in the existing dry-running seal provided by the present invention; Figure 22 This is a schematic diagram of uneven contact between the end faces of the rotating ring and the stationary ring in a conventional dry-running seal provided by the present invention.

[0028] List of reference numerals 1: Bushing; 2: Set screw; 3: Cylindrical pin; 4: Cylindrical head screw; 5: Stationary ring seat; 6: First O-ring; 7: Moving ring; 8: Second O-ring; 9: Retaining ring; 10: First elastic element; 11: Third O-ring; 12: First retaining ring; 13: Stationary ring; 14: Second retaining ring; 15: Fourth O-ring; 16: First push ring; 17: Second elastic element; 18: Drive ring; 19: Axis centerline; 20: Equipment cavity; 21: Rotating shaft; 22: Moving ring seat; 23: Transmission pin; 24: Bushing step; 25: Test bench support; 26: Tooling connection plate; 27: Tooling sealing cavity; 28: GBI interface; 29: Pressure reducing valve; 30: Compressed gas; 31: Test shaft; 32: Connection port; 33: Wire; 34: Spring; 35: Screw; 36: Pressure plate; 37: Connecting screw; 38: Second push ring; 39: Fifth O-ring; 40: Third elastic element; 41: Microgroove; 71: First gap; 72: Second gap; 73: Third gap; 74: Moving ring End face; 75: Unidirectional microgroove; 76: Inner side of moving ring; 77: Outer side of moving ring; 78: Bidirectional microgroove; 101: Spiral groove; 102: Bidirectional groove of bushing; 131: Fourth gap; 132: Fifth gap; 133: Sixth gap; 134: Seventh gap; 180: Drive sealing side; 181: Arc groove; 182: Straight groove; 183: Bidirectional groove of drive ring; 191: First auxiliary line; 192: Second auxiliary line; 200: Atmospheric side; 201: Medium side; 202: 203: Direction of movement of stationary ring; 204: Dynamic pressure of end face groove; 205: Direction of gas flow at room temperature; 206: Direction of gas flow at high temperature; 207: Side of dynamic ring; 208: Rotation direction of bushing; 209: Atmospheric environment; 210: Sealing side of dynamic and stationary rings; 211: Side of drive ring facing away from sealing; 212: Motor side of test bench; 300: Main shaft; 301: Center line of main shaft; 302: Center line of cavity / stationary ring; 303: Center line of main shaft / dynamic ring. Detailed Implementation

[0029] The following is a detailed explanation with reference to the accompanying drawings.

[0030] This invention provides explanations and descriptions of the main terms and concepts.

[0031] Atmospheric environment 209: refers to the external environment in which the seal operates. If the seal is installed outdoors, atmospheric environment 209 refers to the outdoor gas; if the seal is installed indoors, atmospheric environment 209 refers to the indoor gas.

[0032] Medium side 201: also known as the medium end, refers to the side that is relatively closer to the medium. For example, if part A is closer to the medium than part B, then part B's medium side 201 is said to have part A.

[0033] The side facing the medium or the side facing the atmosphere refers to the end of the part that is axially closer to the medium or the end that is closer to the atmosphere. For example, if the left side of part C is closer to the medium than the right side, then the left side of part C is called the side facing the medium, and the right side is called the side facing the atmosphere.

[0034] Atmospheric side 200: Also known as the atmospheric end, it refers to the side that is relatively closer to the atmospheric environment 209. For example, if part D is closer to the atmospheric environment 209 than part E, then part E is said to have part D on its atmospheric side 200.

[0035] Soft materials refer to the material with relatively low hardness among the sealing dynamic and static rings. Since the sealing end faces are subject to wear during dry operation, they are usually not made of the same material. When using different materials for the sealing end faces, a softer material that is more easily worn can be called a soft material. For example, in conventional seal pairings, graphite is a soft material, while silicon carbide is a hard material. The sealing end face refers to the direct contact surface between the end faces of the dynamic and static rings.

[0036] Microgroove 41: refers to a groove with a depth in the micrometer range, such as a dry gas seal dynamic pressure groove with a depth of 5~10um.

[0037] Load factor K: This is a general parameter of mechanical seals, which refers to the ratio of the effective area Ae of the medium pressure on the compensation ring to the end face area A, i.e., K=Ae / A.

[0038] Existing dry-run seals have two drawbacks: First, its application is limited to low-speed conditions: In this sealing structure, the sealing end face operates in contact, and the sealing end face itself lacks external cooling and lubrication design. Its operational stability mainly relies on the excellent self-lubricating properties and high thermal conductivity of the sealing ring material to delay the temperature rise of the end face and extend its service life. However, when the spindle speed increases from 300 rpm, the heat generated by friction on the sealing end face is difficult to dissipate in time, leading to a sharp rise in temperature and causing severe wear. If the wear particles remain in the end face area, they will also form an abrasive effect, further accelerating the damage to the sealing end face.

[0039] Table 1: Relationship between seal linear velocity and wear during normal dry operation

[0040] As shown in Table 1, the wear of conventional dry-running seals increases exponentially with increasing linear velocity. Therefore, conventional dry-running seals can only be used in low-speed equipment, such as reactors and agitators. Dry-running seals are rarely seen in high-speed equipment such as pumps, centrifuges, and high-speed agitators.

[0041] Second: The sealing structure has weak resistance to swaying. For example... Figure 20 As shown, the stationary ring 13, pressure plate 36, and tooling connecting plate 26 are connected as a single unit by screws. The pressure plate 36 completely presses the stationary ring 13, preventing relative movement between it and the tooling connecting plate 26. The tooling connecting plate 26 is fixed to the equipment cavity by connecting screws 37. Figure 21 As shown, in the structure where the spindle 300 is vertically mounted, the spindle centerline 301 is vertical. Components such as the sealing ring 7 are mounted on the spindle 300 using set screws. Theoretically, under the action of the spring force and the pressure of the second medium, the spindle / ring centerline 303 should be aligned with the spindle centerline 301. However, when the equipment cavity is not perpendicular to the spindle 300, if there is a 1° angle between the cavity centerline and the spindle centerline 301, the cavity / ring centerline 302 will also tilt by 1° because the tooling connection plate 26 is directly fixed to the cavity, and the stationary ring 13 is rigidly connected to the tooling connection plate 26 with screws. Figure 22 As shown, this will result in an angle between the stationary ring end face and the rotating ring end face 74, preventing them from achieving uniform contact around the entire circumference and resulting in only localized contact. This easily leads to uneven wear and significantly reduces the seal life. Furthermore, low-speed equipment currently using dry-running seals generally has low machining and assembly precision and poor shaft alignment, further limiting the long-term stable operation capability of this type of seal.

[0042] To address the shortcomings of existing technologies, this invention provides a self-cooling, anti-sway, double-floating dry-running seal.

[0043] Example 1 The self-cooling, anti-yaw, double-floating dry-run seal of the present invention is as follows: Figure 1 As shown, the set screw 2 connects the drive ring 18 to the bushing 1 and fixes it to the rotating shaft 21, allowing it to rotate together with the rotating shaft 21. The third O-ring 11 can prevent the medium from leaking from the gap between the bushing 1 and the rotating shaft 21.

[0044] like Figure 1As shown, the moving ring 7 is located on the outside of the bushing 1, near the stationary ring 13 and defined by a first retaining ring 12 on the bushing 1. The moving ring 7 and the bushing 1 are connected by a fork: symmetrically distributed transmission grooves are provided on the outside of the moving ring 7, corresponding one-to-one with the forks on the outside of the bushing 1. The protruding forks on the bushing 1 insert into the transmission grooves on the moving ring 7. When the bushing 1 rotates with the rotating shaft 21, the forks will drive the moving ring 7 to rotate together. A first elastic element 10 is provided on the side of the moving ring 7 facing away from the stationary ring 13. The first elastic element 10 is, for example, a wave spring. The position of the first elastic element 10 facing away from the moving ring 7 is defined by the bushing step 24 on the outside of the bushing 1. Because the first elastic element 10 is elastic, by reasonably designing the gap between the moving ring 7 and the bushing 1, the moving ring 7 can float axially relative to the bushing 1. Under the action of the dynamic elastic force of the first elastic element 10 and the pressure of the second medium, the retaining ring 9 tightly presses the second O-ring 8, making the second O-ring 8, the retaining ring 9 and the rotating ring 7 into a whole, floating together along the axial direction and rotating together with the rotating shaft 21. The second O-ring 8 can prevent the medium from leaking from the gap between the bushing 1 and the rotating ring 7.

[0045] like Figure 1 As shown, the cylindrical head screw 4 secures the stationary ring seat 5 to the equipment cavity. A first O-ring 6 prevents media leakage from the gap between the stationary ring seat 5 and the equipment cavity. The stationary ring 13 is disposed within the stationary ring seat 5. A second retaining ring 14 limits the displacement range of the stationary ring 13 within the stationary ring seat 5. Multiple evenly distributed second elastic elements 17 are disposed within the stationary ring seat 5. The second elastic elements 17 are preferably cylindrical springs. The second elastic elements 17 push the first push ring 16, which in turn pushes the fourth O-ring 15 to press tightly against the stationary ring 13, causing the first push ring 16 and the fourth O-ring 15 to always float with the stationary ring 13. In other words, the fourth O-ring 15 is positioned between the first push ring 16 and the side of the stationary ring 13 facing away from the moving ring 7. The second elastic elements 17 push the first push ring 16, causing the stationary ring 13 to float axially on the fourth O-ring 15 and achieve a seal.

[0046] The fourth O-ring 15 is used to prevent media leakage from the gap between the stationary ring seat 5 and the stationary ring 13. The cylindrical pin 3 is hammered into the stationary ring seat 5 through an interference fit. Several arc-shaped notches are machined on the outer circumference of the stationary ring 13 and the first push ring 16. These arc-shaped notches pass through the cylindrical pin 3, preventing relative rotation between the stationary ring 13, the first push ring 16 and the stationary ring seat 5, thus preventing rotation of the stationary ring 13 and the first push ring 16.

[0047] like Figure 2 The stationary ring 13 is located in the cavity of the stationary ring seat 5, and its movable direction is 202. The second retaining ring 14 restricts the range of movement of the stationary ring 13, allowing the stationary ring 13 to float axially within the range of the fourth gap 131 and the fifth gap 132.

[0048] like Figure 3The movable ring 7 is shown to move in the direction 203, and the first retaining ring 12 restricts the range of movement of the movable ring 7. The movable ring 7 can float axially within the range of the first gap 71 and the second gap 72.

[0049] like Figure 4 As shown, the double arrows indicate the dynamic pressure 204 of the end face groove. The end face of the moving ring 7 facing the stationary ring 13 has a micro-groove 41. The micro-groove 41 is a dynamic pressure groove (end face groove). The side of the stationary ring 13 with the second elastic element 17 is subjected to the static elastic force (F) of the second elastic element 17. 静弹 ) and the first medium pressure (F 介质1 The side of the moving ring 7 with the first elastic element 10 is subjected to the dynamic force (F) of the wave spring. 动弹 ) and second medium pressure (F 介质2 ).

[0050] Under the axial dynamic action of static elastic force, first medium pressure, dynamic elastic force and second medium pressure, during the process of the moving ring 7 and the stationary ring 13 changing from an unbalanced state to a balanced state, the sealing end faces of the moving ring 7 and the stationary ring 13 can always contact and remain in contact, and achieve bidirectional floating in the axial direction.

[0051] Specifically, under the influence of static elastic force, first medium pressure, dynamic elastic force, and second medium pressure on both sides, the rotating ring end face 74 of the rotating ring 7 and the stationary ring end face of the stationary ring 13 can always be in contact. Due to the sealing and isolation function of the fourth O-ring 15 and the special structural design, the axial thrust from the medium on the rotating ring end face 74 of the rotating ring 7 and the stationary ring end face of the stationary ring 13 is not the same, i.e., F 介质1 <F 介质2 The present invention can balance the total force on the moving ring 7 and the stationary ring 13 by adjusting the magnitude of the elastic force. Specifically, by adjusting the first stiffness and number of the second elastic element 17 and the second stiffness of the first elastic element 10, the moving ring 7 and the stationary ring 13 can achieve force balance even when they are in different positions and the elastic force they receive is different.

[0052] like Figure 1 As shown, at this time, the moving ring 7 and the stationary ring 13 are in theoretical equilibrium. When the entire structure composed of the moving ring 7 and the stationary ring 13 moves towards... Figure 1 When the axis moves to the left as shown, the compression amplitude of the second elastic element 17 on the back of the stationary ring 13 increases, and the elastic force increases, while the compression amplitude of the first elastic element 10 on the back of the moving ring 7 decreases, and the elastic force decreases, until equilibrium is reached. When the entire assembly of the moving ring 7 and the stationary ring 13 moves to the left... Figure 1When the axis moves to the right as shown, the compression amplitude of the second elastic element 17 on the back of the stationary ring 13 decreases, and the elastic force decreases, while the compression amplitude of the first elastic element 10 on the back of the moving ring 7 increases, and the elastic force increases, until equilibrium is reached. The entire assembly consisting of the moving ring 7 and the stationary ring 13 changes from an unbalanced state to a balanced state, which is the bidirectional floating capability of the seal, ensuring that the moving ring end face 74 of the moving ring 7 and the stationary ring end face of the stationary ring 13 always remain in contact.

[0053] Preferably, because Figure 4 The F shown 静弹 F 介质1 F 动弹 F 介质2 Under the combined effect of four forces, the moving ring 7 and the stationary ring 13 tend to close. When the sealing moving ring 7 rotates together with the rotating shaft 21, wear will occur between the moving ring 7 and the stationary ring 13. At this time, under the action of the micro-groove 41 on the end face 74 of the moving ring, the gas inside the sealing ring will be drawn into the space between the moving ring 7 and the stationary ring 13, generating a certain dynamic pressure between the moving ring 7 and the stationary ring 13. This dynamic pressure will cause the end face 74 of the moving ring and the end face of the stationary ring to tend to open, reducing seal wear. Based on the theoretical basis of spiral groove narrow groove, the commonly used spiral groove end face gas film pressure control equation for dry gas seals is: .

[0054] In the formula, p is the pressure, r is the radius of the spiral groove, u is the gas viscosity, and S t R is the mass flow rate of gas passing through the sealing end face, T is the gas temperature, h is the gas film thickness, w is the rotational angular velocity of the sealing ring, h1 is the gas film thickness in the groove area, and g1, g5 and g7 are the spiral groove coefficients, respectively.

[0055] Based on the above control equation, the pressure at the microscopic spiral groove 101 at the specified speed can be calculated, thereby determining the opening force of the seal. According to the calculation results of the above control equation, due to the narrow sealing end face (small spiral groove radius r, and the mass flow rate S through the sealing end face...), t (Also relatively small), the opening force generated by the micro-spiral groove 101 is limited and can be designed to be smaller than the sealing closing force, thereby ensuring the sealing performance between the dry running ring end face 74 and the stationary ring end face.

[0056] When in an ideal state Figure 5The normal clearance between stationary ring 13 and stationary ring seat 5 is shown. Stationary ring 13 and stationary ring seat 5 are concentric. In actual operation of the equipment, the shaft will undergo thermal expansion due to changes in the temperature of the process medium. At the same time, due to changes in the pressure of the first medium and the bearing clearance, the shaft will often move back and forth within a small range along the axial direction, which will cause the moving ring 7 fixed on the bushing 1 and the stationary ring 13 in contact with the moving ring to float along the axial direction. Due to the existence of the sixth clearance (normal clearance between stationary ring 13 and stationary ring seat 5) 133 and the seventh clearance (normal clearance between stationary ring 13 and stationary ring seat 5) 134, when the stationary ring 13 floats along the axial direction, the stationary ring seat 5 will not directly contact the stationary ring 13 and interfere with the floating of the stationary ring 13.

[0057] like Figure 6 As shown, in practical applications, due to the influence of equipment precision, installation precision, and connection precision between various parts, the stationary ring 13 and the stationary ring seat 5 are not as concentric as ideally intended. The stationary ring seat 5 and the axis 19 generally have an angle α. To illustrate this angle α, Figure 6 A first auxiliary line 191 parallel to the axis 19 is added, meaning there is an angle α between the stationary ring seat 5 and the first auxiliary line 191. At this time, the dimensions of the sixth gap 133 and the seventh gap 134 are not uniform. Since the sixth gap 133 and the seventh gap 134 are macroscopic gaps controlled by size, although there is an angle α between the stationary ring 13 and the stationary ring seat 5, the stationary ring 13 and the stationary ring seat 5 do not interfere with each other, and the stationary ring 13 can move left and right along the axis within the stationary ring seat 5.

[0058] When in an ideal state Figure 7 The diagram shows the normal clearance state between the rotating ring 7 and the bushing 1. The rotating ring 7 and the bushing 1 are concentric. During actual operation of the equipment, the shaft will undergo thermal expansion due to changes in the temperature of the process medium. At the same time, due to changes in the pressure of the second medium and the bearing clearance, the rotating shaft 21 will often move back and forth within a small range along the axial direction, which will cause the rotating ring 7, which is fixed on the bushing 1, to float axially. At this time, due to the existence of the third clearance 73 between the rotating ring 7 and the bushing 1, the rotating ring 7 will not directly contact the bushing 1 when it floats axially, and will not interfere with the floating of the rotating ring 7.

[0059] like Figure 8 As shown, in practical applications, due to the influence of equipment precision, installation precision, and connection precision between various parts, the moving ring 7 and the bushing 1 are not as concentric as ideally intended, and the bushing 1 and the axis 19 generally have an included angle b. To illustrate the included angle b, Figure 8A second auxiliary line 192 parallel to the axis 19 is added, meaning there is an angle b between the bushing 1 and the second auxiliary line 192. At this point, the size of the third gap 73 is not uniform. Since the third gap 73 is a macroscopic gap controlled by size, although there is an angle b between the moving ring 7 and the bushing 1, the moving ring 7 and the bushing 1 do not interfere with each other, and the moving ring 7 can float axially on the bushing 1. Due to the bidirectional balanced axial force and the bidirectional floating characteristics of the moving ring 7 and the stationary ring 13, the moving ring 7 and the stationary ring 13 can always maintain a close fit, ensuring that the seal is not affected even if the equipment has a slight sway (the sway does not exceed the sealing design range).

[0060] The microgroove 41 of the present invention includes a unidirectional microgroove 75 and a bidirectional microgroove 78. For example... Figure 9 As shown, the moving ring 7 mates with the stationary ring 13, and multiple uniformly distributed unidirectional micro-grooves 75 are engraved on the end face 74 of the moving ring. The minor diameter D1 of the unidirectional micro-grooves 75 is smaller than the inner diameter d1 of the end face of the stationary ring, to ensure that the gas inside the moving ring 76 can enter the unidirectional micro-grooves 75. Here, the minor diameter refers to the diameter of the circular trajectory formed by the inner edge of the unidirectional micro-grooves 75 (i.e., the diameter of the unidirectional micro-grooves 75 on the side closer to the center of the moving ring 7), which is opposite to the outer diameter of the unidirectional micro-grooves 75 (the diameter of the unidirectional micro-grooves 75 on the side farther from the center), and is a key dimensional parameter for controlling the gas flow path.

[0061] The outer diameter D2 of the unidirectional microgroove 75 is smaller than the outer diameter d2 of the stationary ring end face to ensure that the gas inside the moving ring 76 cannot directly enter the outside of the moving ring 77 through the unidirectional microgroove 75. Figure 9 As shown, when the moving ring 7 is in Figure 9 When the device rotates clockwise, the one-way micro-groove 75 will transport the gas inside the rotating ring 76 to the outer diameter of the one-way micro-groove 75. Since the stationary ring 13 is in contact with the rotating ring 7, and the outer diameter D2 of the one-way micro-groove 75 is smaller than the outer diameter d2 of the stationary ring end face, the gas will be compressed in the one-way micro-groove 75. At this time, the gas pressure in the one-way micro-groove 75 will rise, and the pressure will reach its maximum at the outer diameter D2 of the one-way micro-groove 75. This pressure will cause the rotating ring 7 and the stationary ring 13 to tend to open, which can reduce the wear of the sealing end face.

[0062] because Figure 9 The unidirectional microgroove 75 shown is only suitable for unidirectional rotation of the equipment. When bidirectional rotation of the equipment is possible, the dynamic pressure groove (end face groove) can be designed as a bidirectional microgroove 78, such as... Figure 10 As shown, the end face 74 of the moving ring 7, which mates with the stationary ring 13, is engraved with multiple uniformly distributed bidirectional microgrooves 78. (See figure) Figure 10As shown, the bidirectional microgroove 78 includes at least two pairs of symmetrically arranged arc-shaped grooves. A radial groove is provided at the connection point of the arc-shaped grooves. Preferably, the width of the arc-shaped grooves gradually narrows with the direction of rotation. The outer diameter D3 of the bidirectional microgroove 78 is smaller than the outer diameter d3 of the stationary ring end face, and the inner diameter D4 of the bidirectional microgroove 78 is smaller than the inner diameter d4 of the stationary ring end face, to ensure that the gas inside the moving ring 76 cannot directly enter the outside of the moving ring 77 through the bidirectional microgroove 78. That is, the radial range of the bidirectional microgroove 78 is located between the inner and outer diameters of the stationary ring end face.

[0063] like Figure 10 As shown, when the moving ring 7 rotates with the equipment in any direction of rotation (see...) Figure 10 (The bidirectional rotating arrow in the image) The bidirectional microgroove 78 transports the gas inside the rotating ring 76 towards the outer diameter of the bidirectional microgroove 78. Since the stationary ring 13 is in contact with the rotating ring 7, and the outer diameter D3 of the bidirectional microgroove 78 is smaller than the outer diameter d3 of the stationary ring end face, the gas is compressed within the bidirectional microgroove 78. At this time, the gas pressure within the bidirectional microgroove 78 increases, reaching its maximum at the outer diameter D3 of the bidirectional microgroove 78. This pressure causes the rotating ring 7 and stationary ring 13 to tend to open, which reduces wear on the sealing end face. The calculation of the pressure values ​​at the outer diameter D2 of the unidirectional microgroove 75 and the outer diameter D3 of the bidirectional microgroove 78 is extremely complex, related to parameters such as the spiral groove angle, depth, gas viscosity, and angular velocity. All other parameters being equal, the pressure at the outer diameter D2 of the unidirectional microgroove 75 is proportional to the area of ​​the unidirectional microgroove 75, and the pressure at the outer diameter D3 of the bidirectional microgroove 78 is proportional to the area of ​​the bidirectional microgroove 78. However, the width of the stationary ring end face of this dry gas seal is narrower than that of a conventional dry gas seal, and the areas of the unidirectional and bidirectional microgrooves 75 and 78 are also much smaller than those of the conventional dry gas seal microgrooves, resulting in limited dynamic pressure. According to theoretical calculations, the opening force generated by this dynamic pressure is far less than the closing force of the seal. Therefore, the sealing end faces of the rotating ring 7 and the stationary ring 13 remain in contact, preventing medium leakage into the sealing end faces and preventing gas from entering the medium. This reduces the closing force between the sealing end faces of the rotating ring 7 and the stationary ring 13 in the sealed state, while maintaining a tight seal.

[0064] like Figure 11 As shown, during dry operation, the sealing end faces of the rotating ring 7 and the stationary ring 13 will wear. The gas on the rotating ring side 207 will exchange heat with the rotating ring 7 and the stationary ring 13, forming high-temperature gas (see...). Figure 11 The dotted line indicates that the high-temperature gas refers to a gas with a temperature higher than that of room temperature gas. The outer side of the bushing 1 has evenly distributed spiral grooves 101 machined on it. When the bushing 1 rotates with the shaft 21... Figure 11 When the bushing rotates in the direction 208 shown, it is similar to a screw conveyor, and the screw groove 101 will drive the gas in the screw groove 101 to... Figure 11The leftward flow (see high-temperature gas flow direction 206) transports the high-temperature gas on the moving ring side 207 to the atmospheric side 200 through the spiral groove 101; simultaneously, because the gas on the moving ring side 207 is transported to the atmospheric side 200, a slight negative pressure is formed on the moving ring side 207, and the room-temperature gas on the atmospheric side 200 (which is also a room-temperature and room-pressure gas, see...) Figure 11 The ambient temperature gas flow direction 205 shown will flow through the gap between the stationary ring seat 5 and the bushing 1 to the moving ring side 207. This forms a cycle, continuously transporting the high temperature gas from the moving ring side 207 to the atmospheric side 200. The ambient temperature gas from the atmospheric side 200 then replenishes the moving ring side 207, exchanging heat with the moving ring 7 and the stationary ring 13, carrying away the heat generated by the wear of the moving ring 7 and the stationary ring 13.

[0065] like Figure 11 As shown, the spiral groove 101 is limited by the direction of rotation and only supports unidirectional rotation. When the equipment can rotate in both directions, it can be selected as follows: Figure 12 The bushing has a bidirectional groove 102 shown on the left. The bidirectional groove 102 consists of multiple evenly distributed U-shaped grooves on the outer side of the bushing 1. When the bushing 1 rotates with the rotating shaft 21, the bidirectional groove 102 drives the gas inside to rotate as well, accelerating the flow of gas between the moving ring side 207 and the atmospheric side 200. This allows for more thorough heat exchange between the high-temperature gas on the moving ring side 207 and the ambient temperature gas on the atmospheric side 200, thus removing the heat generated by wear on the sealing surfaces of the moving ring 7 and the stationary ring 13.

[0066] Preferably, the spiral groove 101 enables more thorough exchange of cold / high-temperature gases. In the case of unidirectional rotation of the equipment, a unidirectional spiral groove is preferred.

[0067] like Figure 13 and Figure 14 As shown, multiple evenly distributed arc-shaped grooves 181 are machined on the drive sealing side 180 of the drive ring 18, i.e., the sealing-facing side of the drive ring 18. The arc-shaped grooves 181 extend radially outward from the inner diameter position of the drive ring 18, and the cross-sectional area of ​​the arc-shaped grooves 181 gradually increases with outward extension; that is, as the diameter increases, the cross-sectional length of the arc-shaped grooves 181 gradually increases from L2 to L1. A straight groove 182 is provided at the inner hole position of the drive ring 18. The straight groove 182 mills through the inner hole of the drive ring 18 and communicates with the arc-shaped grooves 181.

[0068] like Figure 14 As shown, when the drive ring 18 is pressed... Figure 14As the axis 21 rotates in the direction shown (see the unidirectional rotating arrow), due to the change in the cross-sectional area of ​​the arc-shaped groove 181, the arc-shaped groove 181 compresses the ambient temperature gas in the atmospheric environment 209 outside the drive ring 18 along the solid line shown in the figure (see the arrow inside the arc-shaped groove 181) and transports this ambient temperature gas to the inner diameter position of the drive ring 18. A portion of the ambient temperature gas flows through the straight groove 182 to the side 211 of the drive ring 18 facing away from the seal, i.e., the atmospheric environment 209. Another portion of the ambient temperature gas flows to the sealing side 210 of the moving ring 7 and the stationary ring 13, forming a linkage with the spiral groove 101 on the outside of the bushing 1, carrying away the high-temperature gas at the sealing end face, so that the high-temperature gas flows from the straight groove 182 to the atmospheric environment 209.

[0069] The arc-shaped groove 181 is designed to transport gas from the outside of the drive ring 18 to the inside of the drive ring 18, thereby enhancing heat exchange. When the direction of the arc-shaped groove 181 is opposite to the rotation direction of the equipment shaft, the gas flow direction in the arc-shaped groove 181 is reversed, with gas from the inside of the drive ring 18 being transported to the outside. This is detrimental to heat exchange in a sealed environment; therefore, the arc-shaped groove 181 is a unidirectional groove. When the equipment can rotate in both directions, a different type of groove can be selected. Figure 15 The drive ring 18 shows a bidirectional groove 183, which is evenly distributed on the sealing side (drive-seal side 180) of the drive ring 18. A straight groove 182 is provided in the inner hole of the drive ring 18, milling through the inner hole and communicating with the bidirectional groove 183. When the device rotates clockwise or counterclockwise, it can drive the gas flow in the drive-seal side 180 of the drive ring 18, enhancing the circulation of room temperature gas and high temperature gas. Preferably, while ensuring that the rotation direction of the device remains unchanged, the drive-seal side 180 of the drive ring 18 is preferably a unidirectional arc-shaped groove.

[0070] Figure 16 This is a schematic diagram showing the flow of gas under the influence of the arcuate groove 181 and straight groove 182 on the drive ring 18, the spiral groove 101 on the outer side of the bushing 1, and the unidirectional micro-groove 75 on the end face 74 of the moving ring. Figure 16As shown, the solid line represents the flow direction of the room temperature gas, and the dashed line represents the flow direction of the high-temperature gas after heat exchange with the sealing end faces of the rotating ring 7 and the stationary ring 13. When the sealing rotating component rotates together with the rotating shaft 21, the axial force generated by the spiral groove 101 on the outer side of the bushing 1 as it rotates with the rotating shaft 21 pushes the high-temperature gas at the sealing end face towards the atmosphere 200, and discharges it into the atmospheric environment 209 through the straight groove 182 in the inner hole of the drive ring 18. Since the high-temperature gas at the sealing end face is driven towards the atmosphere by the spiral groove 101 of the bushing 1, the room temperature gas on the outer side of the drive ring 18 flows inward under the action of the arc groove 181 of the drive ring 18. Between the stationary ring seat 5 and the bushing 1, part of the gas is discharged into the atmospheric environment 209 along with the high-temperature gas pushed by the spiral groove 101, and the other part flows towards the sealing end face, carries away heat, and is then pushed out by the spiral groove 101, forming a cycle. This is the self-cooling method of this sealing scheme. Meanwhile, some gas enters the space between the sealing end faces through the unidirectional micro-groove 75 of the moving ring end face 74, generating dynamic pressure between the end faces to reduce wear.

[0071] like Figure 16 As shown, when the drive ring 18 and bushing 1 rotate together with the rotating shaft 21, the spiral grooves 101 on the drive ring 18 and bushing 1 cause the high-temperature gas at the inner hole of the sealing end face to flow towards the atmospheric environment 209, and cause the cold gas in the atmospheric environment 209 to flow towards the sealing position, thus exchanging heat. Figure 6 and Figure 8 As shown, when the stationary ring seat 5 or the bushing 1 is misaligned, that is, when the rotating shaft 21 is at the misalignment angle, the seal can still ensure the contact of the entire sealing end face of the rotating ring 7 and the stationary ring 13, so that the seal is always in a state of uniform wear and maintaining a seal.

[0072] To reduce seal wear and ensure seal service life, the sealing ring materials of the dry-running seal of this invention are recommended to be paired as follows: graphite vs. silicon carbide, or graphite vs. cemented carbide. The moving ring 7 is a graphite ring with a narrower end face. The stationary ring 13 is a silicon carbide or cemented carbide ring with a wider end face.

[0073] The width of the sealing narrow ring end face ranges from 3 to 10 mm. Within this range, the microgroove 41 can generate a dynamic pressure effect, and the seal will not wear excessively due to an excessively wide end face. Preferably, the width of the sealing narrow ring end face is 7 mm. At this point, within a certain pressure range, the opening force generated by the microgroove 41 can offset approximately 40% of the closing force.

[0074] The sealing load factor K ranges from 0.5 to 1.0. Within this range, the seal can effectively block the process medium. Preferably, the load factor K is 0.76, at which point the sealing closure force is also moderate while ensuring effective blocking of the process medium.

[0075] Example 2 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0076] like Figure 17 As shown, this structure is a schematic diagram of another sealing structure that achieves the same function. Figure 17 and Figure 1 The difference lies in the transmission method and axial displacement limiting method of the moving ring 7. Figure 17 In the structure shown, a bushing step 24 is provided on the outer side of the bushing 1 to restrict the displacement of the moving ring 7 towards the atmosphere 200. A moving ring seat 22 is provided on the side of the moving ring 7 facing the medium. The moving ring seat 22 is restricted from displacement towards the medium side 201 by the first retaining ring 12. A cylindrical pin 3 is provided on the outer side of the bushing 1. One end of the cylindrical pin 3 is fixed to the bushing 1, and the other end extends into the pin groove of the moving ring 7, so that the moving ring 7 can rotate together with the bushing 1. Figure 17 With Figure 1 The difference in the structure shown is that, Figure 17 The structure shown has an additional moving ring seat 22, but the moving ring 7 and bushing 1 are simpler, reducing the processing difficulty and material consumption. This structure can be selected when cost reduction is a consideration.

[0077] like Figure 18 As shown, this structure is a schematic diagram of another sealing structure that achieves the same function. Figure 18 and Figure 1 The difference is that the stationary ring 13 is made of a rigid material and is located inside the stationary ring seat 5. A fourth O-ring 15 is installed in the groove at the outer diameter of the stationary ring 13, that is, the outer circumference of the stationary ring 13 has an O-ring mounting groove, and the fourth O-ring 15 is installed in it, so that the first medium pressure only acts on the side of the stationary ring 13 facing the medium. Multiple evenly distributed cylindrical springs (second elastic elements 17) are installed between the side of the stationary ring 13 facing the atmosphere and the stationary ring seat 5 to provide static elastic force for the stationary ring 13 to counteract the second medium pressure and dynamic elastic force of the moving ring 7. Therefore, the static elastic force of the second elastic element 17 on the back of the stationary ring 13 in this structure is greater.

[0078] Preferably, Figure 18In this design, the moving ring 7 is made of a soft material and is housed within the moving ring seat 22. The moving ring seat 22 is fixed to the outside of the bushing 1 by a set screw 2. A second push ring 38 and a fifth O-ring 39 are disposed between the moving ring 7 and the moving ring seat 22. Multiple evenly distributed third elastic elements 40 are disposed between the second push ring 38 and the moving ring seat 22. Preferably, the third elastic elements 40 are cylindrical springs. The third elastic elements 40 push the second push ring 38 to provide a floating force for the moving ring 7 and press down on the fifth O-ring 39, so that the fifth O-ring 39 always adheres to the moving ring 7 and floats accordingly. Since the second elastic element 17 on the back of the stationary ring 13 does not contact the medium, when there is material in the medium that may clog the spring, the second elastic element 17 on the back of the stationary ring 13 can be guaranteed not to be blocked. When the third elastic element 40 on the back of the rotating ring 7 is blocked, causing the rotating ring 7 to lose its floating property, the axial force applied by the medium to the rotating ring 7 and the dynamic elastic force on the back of the rotating ring 7 will not be transmitted to the stationary ring 13. This allows the second elastic element 17 on the back of the stationary ring 13 to apply a static elastic force to the stationary ring 13 along the axial direction. After offsetting the effect of the second medium pressure, it can also provide a greater floating force to the stationary ring 13, so that the sealing end faces of the rotating ring 7 and the stationary ring 13 can still remain in contact.

[0079] Example 3 To compare the actual friction reduction and cooling effects of various parameters, an experimental fixture for this scheme is provided, such as... Figure 19 As shown, the seal assembly is mounted on the test bench via the tooling connection plate 26, the tooling sealing cavity 27, and auxiliary sealing rings, forming a simulated medium chamber. A test bench support 25 is installed on the motor side 212 of the test bench. The tooling sealing cavity 27 is equipped with a GBI interface 28. The GBI interface 28 is a gas injection interface. During the test, simulated medium is introduced into the simulated medium chamber. During the test, the amount of seal wear and the temperature rise of the sealing ring are compared. The specific testing method is as follows: 1. Wear Amount: The wear amount of the graphite ring is calculated by measuring the thickness difference of the graphite ring before and after the test using a vertical optical comparator. 2. Sealing Ring Temperature: A temperature sensor is bonded to the stationary ring 13. A wire 33 connects to the corresponding strain gauge via a temperature sensor connection port 32 on the tooling connection plate 26. The sensor connection port 32 is plugged with a special plug. The temperature sensor is close to the sealing end face, enabling timely and accurate measurement of the temperature at the sealing end face. Temperature monitoring can accurately determine the cooling effect of various structural parameters on the frictional heat of the sealing end face.

[0080] pass Figure 19 The tooling shown was used to conduct a comparative test on a seal of a certain shaft diameter under the following conditions: pressure 0.2 MPa, speed 3000 rpm. The comparison results are shown in Table 2.

[0081] Table 2: Comparison of heat exchange effects of spiral grooves 101 on drive ring 18 and bushing 1

[0082] As can be seen from Table 2, when there are spiral grooves 101 on the drive ring 18 and the bushing 1, the wear and temperature rise of the stationary ring decrease significantly. The wear of the stationary ring decreases by 12%, and the temperature rise of the stationary ring decreases by 22.7%.

[0083] Table 3: Comparison of whether the dynamic ring end face 74 has a unidirectional microgroove 75

[0084] As can be seen from Table 3, when the end face 74 of the moving ring is designed with a unidirectional microgroove 75, the wear and temperature rise of the stationary ring are significantly reduced, with the wear of the stationary ring decreasing by 59.5% and the temperature rise of the stationary ring decreasing by 48.5%.

[0085] The depth of the unidirectional microgroove 75 ranges from 5 to 20 μm. The preferred depth of the unidirectional microgroove 75 is 8 μm, at which point the sealing dynamic pressure effect is stronger.

[0086] Table 4: Comparison of whether or not the third elastic element 40 is present on the back of the dynamic ring 7

[0087] As can be seen from Table 4, when the third elastic element 40 is designed on the back of the moving ring 7, the wear and temperature rise of the stationary ring are significantly reduced. The wear of the stationary ring is reduced by 26.5%, and the temperature rise of the stationary ring is reduced by 26%.

[0088] Table 5: Comparison of the presence or absence of a third elastic element 40 on the back of the rotating ring 7 when the rotating shaft 21 is misaligned.

[0089] As can be seen from Table 5, when the rotating shaft 21 is deflected, and when the third elastic element 40 is designed on the back of the rotating ring 7, the wear and temperature rise of the stationary ring are significantly reduced. The wear of the stationary ring is reduced by 78.6%, and the temperature rise of the stationary ring is reduced by 46.9%.

[0090] As described above, the comparative tests demonstrate that this structure exhibits significant advantages in terms of low wear and low temperature rise under high-speed operating conditions or when equipment precision is poor, thereby greatly improving the service life of the seal.

[0091] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; phrases such as "preferredly" or "according to a preferred embodiment" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. A self-cooling anti-shake double floating dry-run seal, comprising a bushing (1), a rotating ring (7) and a stationary ring (13). The moving ring (7) is located on the outside of the bushing (1), and the moving ring (7) and the bushing (1) are driven by a shift fork; the stationary ring (13) is located in the cavity of the stationary ring seat (5); Its features are, The moving ring (7) is provided with a first elastic element (10) on the side away from the stationary ring (13), so that the moving ring (7) floats axially relative to the bushing (1); At least one second elastic element (17) is provided in the cavity of the stationary ring seat (5). The second elastic element (17) is connected to the first push ring (16). The first push ring (16) is closely attached to the side of the stationary ring (13) away from the moving ring (7) through the fourth O-ring (15), so that the first push ring (16) and the fourth O-ring (15) always float with the stationary ring (13). The side of the stationary ring (13) away from the moving ring (7) is subjected to static elastic force and first medium pressure applied by the second elastic element (17), and the side of the moving ring (7) away from the stationary ring (13) is subjected to dynamic elastic force and second medium pressure applied by the first elastic element (10). Under the axial dynamic action of static elastic force, first medium pressure, dynamic elastic force and second medium pressure, during the process of the dynamic ring (7) and static ring (13) changing from unbalanced state to balanced state, the sealing end faces of the dynamic ring (7) and static ring (13) are always in contact and remain in contact, and bidirectional floating is achieved in the axial direction. The bushing (1) has evenly distributed spiral grooves (101) on its outer side; It also includes a drive ring (18), and the drive sealing side (180) of the drive ring (18) is provided with several arc-shaped grooves (181). The arc-shaped groove (181) extends outward from the inner diameter of the drive ring (18) along the radial direction of the rotation axis (21), and the cross-sectional area of ​​the arc-shaped groove (181) gradually increases as it extends outward. A straight groove (182) is provided in the inner hole of the drive ring (18). The straight groove (182) mills through the inner hole of the drive ring (18) and communicates with the arc groove (181).

2. The dry-run seal according to claim 1, characterized in that, The steps inside the cavity of the stationary ring (13) and the stationary ring seat (5) are concentric; There is a first gap (71) and a second gap (72) between the stationary ring (13) and the stationary ring seat (5), so that when the stationary ring (13) floats along the axial direction of the rotation axis (21), the stationary ring seat (5) will not directly contact the stationary ring (13) and will not interfere with the floating of the stationary ring (13).

3. The dry-run seal according to claim 1, characterized in that, The moving ring (7) and the bushing (1) are concentric; There is a third gap (73) between the moving ring (7) and the bushing (1). When the moving ring (7) floats along the axial direction, the moving ring (7) will not come into direct contact with the bushing (1) and will not interfere with the floating of the moving ring (7).

4. The dry-run seal according to claim 1, characterized in that, The moving ring (7) that cooperates with the stationary ring (13) has a plurality of unidirectional micro grooves (75) on its moving ring end face (74). The small diameter of the unidirectional micro grooves (75) is smaller than the inner diameter of the stationary ring end face, so as to ensure that the gas inside the moving ring (76) can enter the unidirectional micro grooves (75). The outer diameter of the unidirectional micro groove (75) is smaller than the outer diameter of the stationary ring end face, so as to ensure that the gas inside the moving ring (76) cannot directly enter the outside of the moving ring (77) through the unidirectional micro groove (75).

5. The dry-run seal according to claim 1, characterized in that, The rotating ring (7) that cooperates with the stationary ring (13) has a plurality of bidirectional micro grooves (78) on its rotating ring end face (74). The outer diameter of the bidirectional micro grooves (78) is smaller than the outer diameter of the stationary ring end face, and the inner diameter of the bidirectional micro grooves (78) is smaller than the inner diameter of the stationary ring end face, so as to ensure that the gas inside the rotating ring (76) cannot directly enter the outside of the rotating ring (77) through the bidirectional micro grooves (78).

6. The dry-run seal according to claim 1, characterized in that, When the bushing (1) rotates with the rotating shaft (21), the spiral groove (101) will drive the gas in the spiral groove (101) to flow along the groove direction, and transport the high temperature gas on the moving ring side (207) to the atmospheric side (200) through the spiral groove (101). A slight negative pressure is formed on the moving ring side (207), and the normal temperature gas on the atmospheric side (200) flows to the moving ring side (207) through the gap between the stationary ring seat (5) and the bushing (1), thereby forming a cycle; The high-temperature gas on the moving ring side (207) is continuously transported to the atmospheric side (200), and the normal-temperature gas on the atmospheric side (200) is replenished to the moving ring side (207) and exchanges heat with the moving ring (7) and the stationary ring (13), taking away the heat generated by the wear of the moving ring (7) and the stationary ring (13).

7. The dry-run seal according to claim 1, characterized in that, The bushing (1) has several bidirectional grooves (102) on its outer side. When the bushing (1) rotates with the rotating shaft (21), the bushing bidirectional groove (102) drives the gas in the bushing bidirectional groove (102) to rotate together, accelerating the flow of gas on the moving ring side (207) and the atmospheric side (200), so that the high temperature gas on the moving ring side (207) and the normal temperature gas on the atmospheric side (200) can exchange heat more fully, so as to remove the heat generated by wear on the end faces of the moving ring (7) and the stationary ring (13).

8. The dry-run seal according to claim 1, characterized in that, The drive ring (18) is connected to the bushing (1) and fixed on the rotating shaft (21) so that it can rotate together with the rotating shaft (21); When the drive ring (18) rotates with the rotating shaft (21), the arc groove (181) compresses the room temperature gas in the atmospheric environment (209) outside the drive ring (18) and transports the room temperature gas to the inner diameter position of the drive ring (18). A part of the room temperature gas flows through the straight groove (182) to the atmospheric environment (209) on the side (211) away from the seal of the drive ring (18); another part of the room temperature gas flows to the sealing side (210) of the moving ring (7) and the stationary ring (13), and forms a linkage with the spiral groove (101) on the outside of the bushing (1), taking away the high temperature gas at the sealing end face position, so that the high temperature gas flows from the straight groove (182) to the atmospheric environment (209).

9. The dry-run seal according to claim 1, characterized in that, The bushing (1) has a bushing step (24) on its outer side to limit the displacement of the moving ring (7) toward the atmosphere (200). A rotating ring seat (22) is provided on the side of the rotating ring (7) facing the medium, and the rotating ring seat (22) is restricted from displacement toward the medium side (201) by the first retaining ring (12); A cylindrical pin (3) is provided on the outside of the bushing (1). One end of the cylindrical pin (3) is fixed on the bushing (1), and the other end extends into the pin groove of the moving ring (7), so that the moving ring (7) can rotate together with the bushing (1).

10. The dry-run seal according to claim 1, characterized in that, An O-ring is provided in the groove at the outer diameter of the stationary ring (13) made of hard material, so that the first medium pressure only acts on the side of the stationary ring (13) facing the medium; The moving ring (7) made of soft material is disposed inside the moving ring seat (22), which is fixed to the outside of the bushing (1) by a set screw (2). A second push ring (38) and a fifth O-ring (39) are disposed between the moving ring (7) and the moving ring seat (22).

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