A detachable radial seal with symmetrical grooved conical surface on both sides

Abstract

A detachable radial seal with a symmetrical grooved conical surface on both sides includes an outer ring and an inner ring, wherein the inner ring is located within the outer ring with a micron-level gap between the two rings, and the inner diameter of the inner ring has an interference fit or transition fit with the shaft; the outer ring is a hollow cylinder with circumferential grooves on both the inner and outer surfaces, the circumferential grooves on the outer surface serving as air inlet grooves, and the circumferential grooves on the inner surface facing the inner ring, forming a circumferential sealing cavity, wherein the air inlet groove and the circumferential sealing cavity are connected by a plurality of through holes; the inner ring is composed of a hollow cylinder and two hollow truncated cones, the bottom surfaces of the two hollow truncated cones being connected to the two ends of the hollow cylinder, the circumferential sealing cavity corresponding to the hollow cylinder, and the tapered surfaces of the two hollow truncated cones being used to form a convergent gap area, which generates a dynamic pressure effect through the convergent gap to prevent the sealed fluid at both ends from leaking radially. The present invention promotes the formation of the fluid dynamic pressure effect by constructing a convergent gap, thereby effectively reducing its leakage in the axial direction.

Description

Technical Field

[0001] The present invention belongs to the field of sealing technology, and in particular relates to a detachable radial seal with a symmetrical grooved conical surface on both sides. This type of seal can be used in industrial fields such as aerospace engine rotating systems, nuclear pump spindle systems, and petrochemical hydrogenation feed pump systems. Background Art

[0002] Seals are components used to prevent or reduce fluid leakage. The overall device is generally composed of several parts and may also be equipped with various auxiliary systems. Sealing devices are commonly used in engineering equipment or systems. They prevent or reduce leakage by adopting different sealing methods in different directions (radial, axial, circumferential, etc.); however, no matter what type of sealing device is used, it is almost impossible to achieve zero leakage. Once fluid leakage occurs, it will cause the efficiency of the equipment or system to decrease, causing environmental pollution, personal injury and other problems, and will also bring huge economic losses. In recent years, as equipment or systems have developed in the direction of high speed, high pressure, high reliability, etc., the working conditions they are in have become increasingly complex, and the need to seek new sealing devices and new structures to minimize leakage has become more urgent.

[0003] Seals are divided into axial seals and radial seals according to the direction in which they prevent fluid leakage. That is, seals that prevent radial leakage of fluid are axial seals, and seals that prevent axial leakage of fluid are radial seals. The latter has a wider range of engineering applications. Currently, different patents have discussed the problems existing in radial sealing devices and new structures of sealing devices.

[0004] For example, the patent named "A radial sealing ring for a centrifugal pump with cylindrical guide blades" (patent number CN201810408995.3) discloses a radial sealing ring composed of a disc and radial guide blades, which has multiple radial guide blades evenly fixed along the circumference on one side of the disc, and each radial guide blade is a cylindrical plate. This invention uses radial guide blades to induce the rotating liquid to produce a directional flow in the opposite direction of the movement of the leaking fluid, so as to achieve the purpose of preventing fluid leakage. This invention only guides the sealed fluid, and the large gap of the guide structure cannot enhance the dynamic pressure effect of the high-speed rotating fluid, so its sealing performance still has room for improvement.

[0005] The patent application titled "A Radial Sealing Ring for a Centrifugal Pump" (Patent No. CN202010598192) discloses a sealing ring comprising an upper buckle ring and a lower ring. The upper ring wraps around the lower ring with its two vertical end faces, while grooves and guide surfaces are provided circumferentially on the end face of the lower ring to prevent fluid leakage and reduce volume loss in the centrifugal pump. This invention, similar in structure to the aforementioned inventions, focuses on guiding leaking fluid to reduce leakage, but its direct blocking effect on the fluid is not significant.

[0006] On the other hand, the prevention of fluid leakage can be improved by changing the surface features of the seal or the rotor that cooperates with it. Such surface modification schemes that improve sealing performance are gradually being used to develop new radial seal structures.

[0007] For example, the patent titled "A Rotary Groove Labyrinth Seal Structure" (Patent No. CN202210931146.2) discloses a sealing structure with a rotary groove seal ring. This structure adds a series of swirl-exciting grooves that rotate in the opposite direction of the rotor's normal working direction to the traditional labyrinth seal structure. The addition of the rotary grooves reduces the circulation velocity of the seal structure and improves the stability of the rotor system. However, this structure still has a large radial gap, resulting in significant leakage.

[0008] The patent titled "Floating Ring Seal Assembly with Inclined Grooves" (Patent No. CN201710454558.0) discloses a sealing assembly for sealing lubricating oil in a bearing cavity, comprising a raceway and a floating ring. The raceway has an inclined groove disposed on its radial outer surface. During operation, the lubricating oil in the groove forms a sealing oil ring, improving sealing performance. These invention patents all improve sealing performance by modifying the local structure of the seal. However, due to the structural characteristics of this type of floating ring seal, the structure is generally compact and relatively small overall, which poses certain limitations for use in operating conditions requiring a larger overall structure.

[0009] Patents titled "A Sealing Ring" (Patent No. CN201510298133.6) and "A Shallow Groove Mechanical Seal" (Patent No. CN201510298134.0) respectively disclose a slotted sealing ring and a shallow groove mechanical seal using the slotted sealing ring. These two inventions create a three-dimensional convergent region that gradually becomes shallower and narrower from the high-pressure side to the low-pressure side by opening a shallow groove with a curved bottom surface on the sealing end face of the dynamic or static ring of the mechanical seal. This has a stronger convergence effect and can improve the stability and reliability of the mechanical seal. This invention achieves blocking of radial fluid leakage through end face sealing, rather than radial sealing, and therefore cannot achieve the radial sealing function.

[0010] In summary, in order to address the shortcomings of the seals shown in the above-mentioned patents and to adapt to increasingly complex sealing conditions, it is necessary to combine the current theoretical and experimental research progress of seals to develop radial seals that are easier to manufacture and install and have better sealing performance. Summary of the Invention

[0011] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a detachable radial seal with a symmetrical grooved conical surface on both sides. By constructing a convergent gap, the formation of a fluid dynamic pressure effect is promoted, which can effectively reduce its axial leakage. At the same time, it is also easy to manufacture and install. The overall structure will have good sealing performance while also taking into account its working stability and reliability.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A detachable radial seal with a symmetrical grooved conical surface on both sides, comprising an outer ring and an inner ring, wherein the inner ring is located within the outer ring with a micrometer-level gap between the two, and the inner diameter of the inner ring has an interference fit or a transition fit with the shaft;

[0014] The outer ring is a hollow cylinder with circumferential grooves on both the inner and outer surfaces. The circumferential groove on the outer surface serves as an air inlet groove, and the circumferential groove on the inner surface is opposite to the inner ring to form a circumferential sealing cavity. The air inlet groove and the circumferential sealing cavity are connected through a plurality of through holes.

[0015] The inner ring is composed of a hollow cylinder and two hollow truncated cones. The bottom surfaces of the two hollow truncated cones are respectively connected to the two ends of the hollow cylinder. The circumferential sealing cavity corresponds to the hollow cylinder. The tapered surfaces of the two hollow truncated cones are used to form a convergent gap area. The dynamic pressure effect is formed through the convergent gap to prevent the sealed fluid at both ends of the axial direction from leaking radially.

[0016] In one embodiment, the air inlet groove and the circumferential sealing cavity are both single grooves and are both located at the axial center of the outer ring, and the through holes are multiple holes arranged in a single row on the same circumference.

[0017] In one embodiment, the groove depth of the air inlet groove and the cavity depth of the circumferential sealing cavity are in the millimeter order, the axial cross-section of the air inlet groove is rectangular, and the width is 1 / 5 to 1 / 9 of the axial length of the inner ring; the axial cross-section of the circumferential sealing cavity is rectangular, and the width is 1 / 4 to 1 / 3 of the axial length of the inner ring, and is less than or equal to the axial length of the hollow cylinder; the through hole radially connects the air inlet groove and the circumferential sealing cavity, and the length is 0.4 to 0.9 times the wall thickness of the outer ring, and the hole diameter ranges from 0.5 to 3 mm; the wall thickness of the outer ring is 1 / 2 of the difference between the outer diameter of the outer ring and the inner diameter of the outer ring.

[0018] In one embodiment, the through hole serves as an exhaust hole, the air inlet groove is a low fluid pressure area, the circumferential sealed cavity is a high pressure area, and the fluid leaks from the inside to the outside through the exhaust hole; or, the through hole serves as an air inlet hole, the circumferential sealed cavity is a low fluid pressure area, the air inlet groove is a high pressure area, and the fluid leaks from the outside to the inside through the air inlet hole, wherein the fluid is a process gas medium that is incompatible with the sealed fluid, and the leakage channel is blocked by the air intake to achieve zero leakage of the sealed fluid.

[0019] In one embodiment, the inner ring is symmetrical along the entire axial center section of the seal, and the axial lengths of the two hollow truncated cones are equal and are equal to the axial length of the hollow cylinder.

[0020] In one embodiment, the taper of the hollow truncated cone ranges from 10° to 45° and is designed for the purpose of reducing leakage. The larger the taper, the stronger the dynamic pressure effect.

[0021] In one embodiment, the tapered surfaces of the two hollow truncated cones are uniformly distributed with multiple groups of modified groove structures or micro-textures along the circumferential direction; the number of modified groove structures or micro-textures on the two hollow truncated cones is the same and they are symmetrical about the entire axial center section of the seal, and the area occupied by the modified groove structure or micro-texture is 1 / 4 to 2 / 3 of the area of ​​the entire tapered surface.

[0022] In one embodiment, the groove type of the modified groove structure is a spiral groove, a rectangular groove, a triangular groove or a circular groove, and the groove depth is in the micron level; the micro texture is a single row or multiple rows of circular micro pits, triangular micro pits, square micro pits or rectangular micro pits, and the groove depth is in the millimeter level.

[0023] In one embodiment, the spiral groove is a logarithmic, involute or developed line, and the spiral grooves on the two hollow truncated cones have opposite rotation directions.

[0024] In one embodiment, the size of the gap is 1.5‰ to 5‰ of the inner diameter of the inner ring, and its size at the minimum gap is 0.1-150 μm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention comprises an outer ring 1 and an inner ring 2 that are clearance-fitted, with a small gap 3 therebetween to facilitate disassembly and installation. When a sealed fluid is located at both axial ends of the present invention and the present invention rotates circumferentially with the sealed shaft, leakage of the sealed fluid through the gap 3 can be reduced or prevented due to the dynamic pressure effect generated by the taper of the truncated cones 2-2 at both ends of the inner ring 2, the pumping effect and dynamic pressure effect generated by the micro-texture or modified grooves 2-2-1 formed on the truncated cones 2-2, and the blocking of leakage paths by inert pressurized gas injected through the through-holes 1-2 in the outer ring 1.

[0027] 2. The present invention can adapt to sealing requirements under different operating conditions by varying the taper of the inner ring's symmetrical conical surface and the number and shape of the modified grooves on the surface. A greater taper on the inner ring's symmetrical conical surface increases its dynamic pressure effect and can withstand greater fluid pressure. A greater number of modified grooves increases the dynamic pressure effect and reduces the flow rate of the sealed fluid into the gap. Different modified groove shapes produce different levels of dynamic pressure effect. Spiral grooves produce a stronger dynamic pressure effect than circular grooves and also create a pumping effect, reducing the flow rate of the sealed fluid entering the gap.

[0028] 3. The present invention injects inert pressurized gas into the gap between the inner and outer rings through the through holes distributed circumferentially on the outer ring. When the pressure of the sealed fluid in the gap is relatively small, that is, the pressure of the sealed fluid in the circumferential sealing cavity 1-3 is less than the pressure of the injected fluid in the air inlet groove 1-1, zero leakage of the sealed fluid can be achieved because the leakage channel is completely blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention.

[0030] Figure 2 This is a radial view of the outer ring of the present invention.

[0031] Figure 3 yes Figure 2 Middle AA section view.

[0032] Figure 4 Schematic diagram of the inner ring structure (micro texture) of the present invention.

[0033] Figure 5 Schematic diagram of the inner ring structure (spiral groove) of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0035] The present invention is a detachable radial seal with a symmetrical grooved conical surface on both sides, which forms or enhances the dynamic pressure effect of the sealing interface by constructing a convergent gap, thereby improving the ability to prevent and control fluid leakage along the axial direction. Figures 1 to 5 As shown, it includes an inner ring 2 and an outer ring 1 or can be composed of only the inner ring 2 and the outer ring 1. The inner ring 2 has a slotted symmetrical conical surface, and the outer ring 1 has leakage holes (i.e., air inlet holes) distributed circumferentially. The present invention has good radial sealing performance and can prevent or reduce axial leakage of the medium.

[0036] Specifically, the inner ring 2 is located in the outer ring 1, and the two are clearance-fitted and preferably coaxially arranged. The inner diameter of the inner ring 2 has an interference fit or transition fit with the shaft, and the gap 3 between the inner ring 2 and the outer ring 1 is in the micron level.

[0037] like Figure 2 and Figure 3The outer ring 1 is a hollow cylinder with circumferential grooves on both the inner and outer surfaces. The circumferential groove on the outer surface serves as an air inlet groove 1-1, and the circumferential groove on the inner surface is opposite to the outer surface of the inner ring 2, forming a circumferential sealing cavity 1-3. The air inlet groove 1-1 is connected to the circumferential sealing cavity 1-3 through a number of through holes 1-2. Depending on the purpose, the through holes 1-2 serve as air inlet holes or leakage holes.

[0038] like Figure 4 and Figure 5 The inner ring 2 consists of a hollow cylinder 2-1 and two hollow truncated cones 2-2. The bottom surfaces of the two hollow truncated cones 2-2 are connected to the two ends of the hollow cylinder 2-1, forming a convex structure along the axial cross-section, with the symmetry centerlines of the three elements coinciding. The circumferential sealing cavity 1-3 corresponds to the hollow cylinder 2-1. The tapered surfaces of the two hollow truncated cones 2-2 form a convergent gap area. This convergent gap area promotes a dynamic pressure effect during the rotation of the inner ring, preventing radial leakage of the sealed fluid at both ends of the axial direction.

[0039] The structure of the present invention facilitates disassembly and installation of the inner ring 2 and outer ring 1 due to the clearance fit. During use, the sealed fluid is located at both axial ends of the detachable radial seal. During circumferential rotation, the dynamic pressure effect generated by the taper of the truncated cone 2-2 allows inert pressurized gas to be injected through the through hole 1-2, blocking the leakage path and preventing leakage of the sealed fluid.

[0040] In some embodiments of the present invention, the air inlet groove 1-1 and the circumferential sealing cavity 1-3 are both single grooves and are both located at the axial center of the outer ring 1. The through holes 1-2 are multiple holes arranged in a single row on the same circumference, and the number can be 1 to 10. The number value is designed according to the sealing working conditions and structural parameters, and all through holes 1-2 are evenly distributed along the circumference.

[0041] This embodiment adopts a single-groove, single-row hole structure, which has a simple manufacturing process and has little impact on the overall structural strength of the outer ring. At the same time, the single groove can achieve pressure reduction, and the single-row hole has a throttling function, which is more conducive to achieving the sealing performance target.

[0042] In some embodiments of the present invention, the groove depth (along the radial direction) of the air inlet groove 1-1 and the cavity depth (along the radial direction) of the circumferential sealing cavity 1-3 are in the millimeter order, ranging from 0.5 to 5 mm. The axial cross-section of the air inlet groove 1-1 is rectangular, and the width (i.e., the axial length) is 1 / 5 to 1 / 9 of the axial length of the inner ring 2. The axial cross-section of the circumferential sealing cavity 1-3 is rectangular, and the width (i.e., the axial length) is 1 / 4 to 1 / 3 of the axial length of the inner ring 2, and is less than or equal to the axial length of the hollow cylinder 2-1; the through hole 1-2 radially connects the air inlet groove 1-1 and the circumferential sealing cavity 1-3, and the length is 0.4 to 0.9 times the wall thickness of the outer ring, and the hole diameter ranges from 0.5 to 3 mm; the wall thickness of the outer ring 1 is 1 / 2 of the difference between the outer diameter and the inner diameter of the outer ring, and is also the sum of the groove depth of the air inlet groove 1-1, the cavity depth of the axial sealing cavity 1-3 and the length of the through hole 1-2.

[0043] The setting of the axial length of the circumferential sealing cavity 1 - 3 can prevent an increase in the amount of sealed fluid flowing into the gap 3 and the axial sealing cavity 1 - 3 , thereby preventing further leakage of the sealed fluid.

[0044] The parameter selection of this embodiment can not only ensure a relatively simple manufacturing process, but also effectively utilize the dynamic pressure effect of the high-speed rotating fluid through structural changes, reduce the flow rate of the sealed fluid flowing into the gap 3 and the axial sealing cavity 1-3, and the sealed fluid or pressurized fluid can smoothly pass through the opened air inlet groove 1-1, through hole 1-2, and circumferential sealing cavity 1-3, thereby realizing the blocking function of the sealed fluid and having good sealing performance.

[0045] The through hole 1-2 can be used as an exhaust hole or an air inlet. In some embodiments of the present invention, when the through hole 1-2 is used as an exhaust hole, the air inlet groove 1-1 is a low fluid pressure area, the circumferential sealed cavity 1-3 is a high pressure area, and the fluid leaks from the inside to the outside through the exhaust hole; when the through hole 1-2 is used as an air inlet, the circumferential sealed cavity 1-3 is a low fluid pressure area, the air inlet groove 1-1 is a high pressure area, and the fluid leaks from the outside to the inside through the air inlet. In this case, the fluid can be an inert gas or other process gas medium incompatible with the sealed fluid. The leakage channel is blocked by the air inlet, achieving zero leakage of the sealed fluid.

[0046] In some embodiments of the present invention, the inner ring 2 is symmetrical along the entire axial center section of the seal. The axial lengths of the two hollow truncated cones 2-2 are equal, and equal to the axial length of the hollow cylinder 2-1. That is, the ratio of the axial lengths of the two hollow truncated cones 2-2 to the axial length of the middle hollow cylinder 2-1 is 1:1:1. The outer ring 1 and the inner ring 2 form two symmetrical converging gap regions, and the gap region located between the two converging gap regions, for a total of three gap regions. All three gap regions have the same axial length. The taper of the hollow truncated cones 2-2 of the present invention ranges from 10° to 45°, with a greater taper resulting in a stronger dynamic pressure effect. Design is based on actual operating conditions to reduce leakage (by reducing the seal gap flow and pressure), resulting in different converging gap regions, thereby achieving better sealing performance.

[0047] In some embodiments of the present invention, the conical surfaces of the two hollow truncated cones 2-2 are uniformly distributed with multiple groups of modified groove structures 2-2-1 or micro-textures along the circumferential direction, and are circumferentially symmetrically distributed on the outer surface; the number of modified groove structures 2-2-1 or micro-textures on the two hollow truncated cones 2-2 is the same, and they are symmetrical about the entire axial center section of the seal, and the area occupied by the modified groove structure 2-2-1 or micro-texture is 1 / 4 to 2 / 3 of the area of ​​the entire conical surface.

[0048] The micro-textured or modified grooves 2-2-1 enable a pumping effect and further enhance the dynamic pressure effect.

[0049] In some embodiments of the present invention, the number of modified grooves on the tapered surface of a single hollow truncated cone 2-2 is 4 to 16. The groove type of the modified groove structure 2-2-1 can be a spiral groove (the type line can be a logarithmic, involute, or expansion line, etc.), a rectangular groove, a triangular groove, or a circular groove, etc. The groove depth is on the micron level, ranging from 0.1 to 10 μm, which helps to form a dynamic pressure effect. In particular, when using spiral grooves, the rotation direction of the spiral grooves on the two hollow truncated cones 2-2 should be opposite. When the rotation direction of multiple sets of spiral grooves is opposite to the rotation direction of the inner ring, the pumping effect of the spiral grooves can reduce the flow rate through the sealing gap, thereby reducing leakage generated through the gap.

[0050] In some embodiments of the present invention, the micro texture is a single row or multiple rows of circular micro pits, triangular micro pits, square micro pits or rectangular micro pits, etc., and the groove depth is millimeter level, ranging from 0.1 to 3 mm, which is conducive to the formation of dynamic pressure effect.

[0051] In some embodiments of the present invention, the size of the gap 3 is generally 1.5‰ to 5‰ of the inner diameter of the inner ring, and its size at the minimum gap is 0.1-150 μm, which is a micron-level gap.

[0052] The following are two specific embodiments of the present invention.

[0053] Example 1

[0054] Aiming at the goal of zero leakage sealing of the sealed medium in a high-speed working condition, a detachable radial seal with symmetrical grooved conical surfaces on both sides is proposed. The seal is further described in detail below with reference to the accompanying drawings.

[0055] Reference Figure 1 In this embodiment, a bilaterally symmetrical grooved conical surface detachable radial seal includes an outer ring 1 and an inner ring 2, wherein:

[0056] The outer ring 1 is a hollow cylinder, and its structure is as follows Figure 2 and Figure 3 It includes a circumferential air inlet groove 1-1 and a through hole 1-2 on the outer surface which are symmetrical along the axial center section of the outer ring, and a circumferential sealing cavity 1-3 on the inner surface which is symmetrical along the axial center section of the outer ring.

[0057] The outer ring 1 is a hollow cylinder, and an air inlet groove 1-1 is opened along the circumferential direction on the outer surface of the hollow cylinder. A plurality of single-row through holes 1-2 are evenly distributed in the groove, serving as air inlet holes. In this embodiment, the outer diameter of the outer ring is 60 mm, the inner diameter is 50 mm, the radial thickness is 5 mm, and the axial width is 9 mm.

[0058] The air inlet groove 1-1 is opened along the circumference of the outer surface of the outer ring 1. Figure 2 As shown, the center line of the groove is equidistant from both ends of the hollow cylinder, and multiple single-row through holes 1-2 are evenly distributed in the air inlet groove 1-1; the radial groove depth of the air inlet groove 1-1 is 1mm, the axial cross-section of the groove is rectangular, and the axial width is 1mm.

[0059] The single row of through holes 1-2 is located in the air inlet groove 1-1, such as Figure 2 As shown, they are evenly distributed along the circumference, with all circle centers located on the center line of the air inlet groove 1-1 and the circumferential sealing cavity 1-3, and both ends are connected to the air inlet groove 1-1 and the circumferential sealing cavity 1-3 respectively, and the axis is orthogonal to the axis of the hollow cylinder; there are 4 leakage holes, with an interval of 90° between adjacent leakage holes, a length of 3 mm, a diameter of 0.5 mm, and a length-to-diameter ratio of 6.

[0060] The circumferential sealing cavity 1-3 is opened along the inner surface of the outer ring 1. Figure 3 As shown, its upper end is connected to the through hole 1-2, and the end is connected to the gap 3 between the outer ring 1 and the inner ring 2, where the line is equidistant from the two end faces of the outer ring 1; the circumferential sealing cavity 1-3 has a radial cavity depth of 1mm, a rectangular axial cross-section, and an axial width of 3mm.

[0061] The sealed air inlet groove 1-1 and the sealed cavity 1-3, when air is admitted through the through hole 1-2, the air inlet groove 1-1 is a high fluid pressure area, the circumferential sealed cavity 1-3 is a low pressure area, and the fluid leaks inward. At this time, the fluid can be an inert gas or other process gas medium (such as nitrogen) that is incompatible with the sealed fluid. The leakage channel is blocked by air intake, thereby achieving zero leakage of the sealed fluid.

[0062] Inner ring 2, its structure is as follows Figure 4 , including a hollow cylinder 2-1, a hollow truncated cone 2-2 and a modified groove structure 2-2-1.

[0063] The inner ring 2 consists of a hollow cylinder 2-1 and a pair of bilaterally symmetrical hollow truncated cones 2-2, with a convex axial cross-section. The three symmetric centerlines coincide, and the lower bases of the two truncated cones coincide with the two bases of the cylinder. The inner ring's ends are connected by two upper bases of truncated cones, with two tapered surfaces forming a convergent clearance area. The inner ring's inner diameter has an interference fit or transition fit with the shaft, allowing it to rotate with the rotor. The inner ring has an outer diameter of 50mm and an inner diameter of 40mm.

[0064] The hollow truncated cone 2-2 is bilaterally symmetrical along the entire sealing axial center section, and the ratio of the left and right axial lengths to the axial length of the middle hollow cylinder 2-1 is 1:1:1; both are 3 mm.

[0065] The taper of the hollow truncated cone 2-2 is 15°. In this embodiment, the bearing operates at high speeds, and the high-speed rotation creates high pressure within the medium, which can easily cause leakage through the air inlet. To prevent this, the taper of the truncated cone should be designed to minimize the flow of medium through the gap between the inner and outer rings. A larger taper increases the dynamic pressure effect. Furthermore, considering that fluid flows from the high-pressure air inlet groove 1-1 to the low-pressure circumferential sealing cavity 1-3 through the through hole 1-2, zero leakage of the sealed fluid can be achieved through air intake. For this reason, a 15° taper is chosen for the truncated cone, taking all factors into consideration.

[0066] The hollow truncated cone 2-2 has multiple groups of circular modified groove structures 2-2-1 evenly distributed along the circumferential direction on the outer side surface, which are symmetrically distributed on the outer surface. The same number of circular grooves are set on the left and right sides of the cone; in this embodiment, the number of circular grooves on the cone side is 16, the groove depth is 1μm; the diameter of the circular groove is 2mm.

[0067] The symmetrical grooved conical surfaces of this embodiment can be split into radial seals, and there is a clearance fit between the outer ring 1 and the inner ring 2. The minimum clearance is designed to be 1.5‰ of the inner ring's inner diameter, or 60μm; the maximum clearance is approximately 1.35mm.

[0068] Example 2

[0069] In view of the situation where there is a high pressure fluid inside the seal, a radial seal with symmetrical grooved conical surfaces on both sides is proposed, which is further described in detail below with reference to the accompanying drawings.

[0070] In this embodiment, a bilaterally symmetrical grooved conical surface detachable radial seal includes an outer ring 1 and an inner ring 2.

[0071] The structure and structural parameters of the outer ring 1 are the same as those of Example 1, and will not be repeated here.

[0072] Inner ring 2, its structure is as follows Figure 5 , including a hollow cylinder 2-1, a hollow truncated cone 2-2 and a modified groove structure 2-2-1.

[0073] The structure of the inner ring 2 is the same as that of Example 1, except for the taper of the hollow truncated cone 2-2 and the modified groove structure 2-2-1. Only the structural parameters are different. In this embodiment, the outer diameter of the inner ring is 50 mm and the inner diameter is 25 mm.

[0074] The hollow truncated cone 2 - 2 has a taper of 40° so as to enhance the dynamic pressure effect, thereby reducing the flow of the medium entering the gap 3 and improving the sealing ability.

[0075] The modified groove structure 2-2-1 has a spiral groove structure. The spiral grooves on the left and right cone sides have opposite rotation directions, and the rotation direction is also opposite to the rotation direction of the inner ring. When the inner ring rotates, based on the pumping effect of the spiral groove, the flow rate of the medium passing through the gap can be reduced, thereby reducing leakage; in this embodiment, the number of modified grooves on the cone side is 16, the groove depth is 1μm, the spiral angle is 45°; the spiral groove width is 2mm.

[0076] Symmetrical grooved conical surfaces on both sides enable splitting of the radial seal, with a clearance fit between the outer ring 1 and the sealing inner ring 2. The minimum clearance is designed to be 3‰ of the inner ring's inside diameter, or 75μm; the maximum clearance is approximately 8.4mm.

Claims

1. A detachable radial seal with a bilaterally symmetrical grooved conical surface, characterized in that: The invention comprises an outer ring (1) and an inner ring (2), wherein the inner ring (2) is located in the outer ring (1) and there is a micrometer-level gap (3) between the inner ring (2) and the shaft, and the inner diameter of the inner ring (2) is interference fit or transition fit; The outer ring (1) is a hollow cylinder, and has circumferential grooves on both the inner and outer surfaces. The circumferential groove on the outer surface serves as an air inlet groove (1-1), and the circumferential groove on the inner surface is opposite to the inner ring (2) to form a circumferential sealing cavity (1-3). The air inlet groove (1-1) and the circumferential sealing cavity (1-3) are connected through a plurality of through holes (1-2). The inner ring (2) is composed of a hollow cylinder (2-1) and two hollow truncated cones (2-2). The bottom surfaces of the two hollow truncated cones (2-2) are respectively connected to the two ends of the hollow cylinder (2-1). The circumferential sealing cavity (1-3) corresponds to the hollow cylinder (2-1). The conical inclined surfaces of the two hollow truncated cones (2-2) are used to form a convergent gap area. The dynamic pressure effect is formed by the convergent gap to prevent the sealed fluid at the two axial ends from leaking radially.

2. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The air inlet groove (1-1) and the circumferential sealing cavity (1-3) are both single grooves and are both located at the axial center of the outer ring (1); the through holes (1-2) are multiple holes arranged in a single row on the same circumference.

3. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The groove depth of the air inlet groove (1-1) and the cavity depth of the circumferential sealing cavity (1-3) are in the millimeter order, the axial cross-section of the air inlet groove (1-1) is rectangular, and the width is 1 / 5 to 1 / 9 of the axial length of the inner ring (2), the axial cross-section of the circumferential sealing cavity (1-3) is rectangular, and the width is 1 / 4 to 1 / 3 of the axial length of the inner ring (2), and is less than or equal to the axial length of the hollow cylinder (2-1); the through hole (1-2) radially connects the air inlet groove (1-1) and the circumferential sealing cavity (1-3), the length is 0.4 to 0.9 times the wall thickness of the outer ring (1), and the hole diameter ranges from 0.5 to 3 mm; the wall thickness of the outer ring (1) is 1 / 2 of the difference between the outer diameter of the outer ring and the inner diameter of the outer ring.

4. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The through hole (1-2) serves as an exhaust hole, the air inlet groove (1-1) is a low fluid pressure area, the circumferential sealing cavity (1-3) is a high pressure area, and the fluid leaks from the inside to the outside through the exhaust hole; or, the through hole (1-2) serves as an air inlet hole, the circumferential sealing cavity (1-3) is a low fluid pressure area, the air inlet groove (1-1) is a high pressure area, and the fluid leaks from the outside to the inside through the air inlet hole, wherein the fluid is a process gas medium incompatible with the sealed fluid, and the leakage channel is blocked by the air inlet, thereby achieving zero leakage of the sealed fluid.

5. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The inner ring (2) is symmetrical along the entire sealing axial center section, and the axial lengths of the two hollow truncated cones (2-2) are equal and are also equal to the axial length of the hollow cylinder (2-1).

6. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The taper of the hollow truncated cone (2-2) ranges from 10° to 45° and is designed for the purpose of reducing leakage. The larger the taper, the stronger the dynamic pressure effect.

7. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The conical inclined surfaces of the two hollow truncated cones (2-2) are uniformly distributed with multiple groups of modified groove structures (2-2-1) or micro-textures along the circumferential direction; the modified groove structures (2-2-1) or micro-textures on the two hollow truncated cones (2-2) are the same in number and symmetrical about the entire axial center cross section of the seal, and the area occupied by the modified groove structures (2-2-1) or micro-textures is 1 / 4 to 2 / 3 of the area of ​​the entire conical inclined surface.

8. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The groove type of the modified groove structure (2-2-1) is a spiral groove, a rectangular groove, a triangular groove or a circular groove, and the groove depth is in the micrometer level; the micro texture is a single row or multiple rows of circular micro pits, triangular micro pits, square micro pits or rectangular micro pits, and the groove depth is in the millimeter level.

9. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 8, characterized in that: The spiral groove is a logarithmic, involute or expansion line, and the spiral grooves on the two hollow truncated cones (2-2) have opposite rotation directions.

10. The bilaterally symmetrical grooved conical surface detachable radial seal according to claim 1, characterized in that: The size of the gap (3) is 1.5‰ to 5‰ of the inner diameter of the inner ring, and its size at the minimum gap is 0.1-150 μm.

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