Floating ring type damping sealing device

Abstract

The invention relates to the field of damping sealing, in particular to a floating ring type damping sealing device which comprises a shell and a rotating shaft, a floating ring structure used for preventing a large amount of high-pressure gas in a machine from leaking is arranged on the shell, and the floating ring structure comprises a limiting ring used for blocking the high-pressure gas in the machine. The outer wall of the shell is provided with an acoustic emission sensor used for monitoring contact sound of the rotating shaft and the limiting ring, an elastic assembly used for providing elastic support for the limiting ring is arranged in the shell, and the shell is provided with a gas injection mechanism used for providing center support for the limiting ring through high-pressure gas. The gas injection mechanism comprises a sealing ring set used for compensating a gap between the limiting ring and the inner wall of the shell. A uniform air pressure supporting layer is formed through the air injection mechanism, the limiting ring can flexibly move along with the rotating shaft, dynamic eccentricity and vibration of the rotating shaft are effectively compensated, meanwhile, a high-rigidity air film is formed through the dynamic pressure groove set formed by combining the deep groove and the shallow groove, and it is ensured that a sealing gap is stable.

Description

Technical Field

[0001] This invention relates to the field of damping seals, and more particularly to a floating ring damping seal device. Background Technology

[0002] Floating ring seals are a technology that uses the effects of fluid dynamic pressure and static pressure to achieve non-contact sealing. They are widely used in high-speed rotating machinery such as centrifugal compressors, steam turbines, and aero engines.

[0003] Existing technologies often employ a bellows spring and a floating ring sealing device equipped with it, as disclosed in CN203395062U. This device uses a split floating ring, consisting of a graphite ring and a steel sleeve, and uses a bellows spring, gaskets, and locking plates to achieve axial elastic limiting of the floating ring. However, this type of existing floating ring sealing technology still has the following prominent problems in actual high-speed, high-temperature, and variable-condition operation: First, existing devices mainly rely on fluid film pressure and spring force to achieve the following of the floating ring. During equipment start-up and shutdown, exceeding critical speed, or sudden load changes, the shaft vibrates violently. If the gas film fails to establish in time or its stiffness is insufficient, the floating ring response is lagging, easily leading to rubbing between the ring and the shaft, or even causing shaft seizure, seriously affecting sealing reliability and equipment safety. Secondly, under high-temperature conditions, the floating ring, as a whole or assembly, expands due to heat. Often, due to mismatched material thermal expansion coefficients or structural constraints, the inner hole of the sealing ring becomes out of round, and the gap between it and the shell disappears, leading to thermal jamming, loss of floating ability, and rapid seal failure. Finally, existing floating ring sealing devices typically lack built-in operational condition monitoring. The sealing ring is located inside the machine, making it difficult for external sensors to effectively detect minor friction or abnormal vibrations during operation. Often, by the time leakage increases significantly or equipment vibration becomes abnormal, the fault has already developed into serious damage, resulting in high maintenance costs and low safety. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of limited adaptive capability, easy thermal jamming failure, and insufficient early warning capability in the prior art, and to propose a floating ring damping sealing device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A floating ring damping sealing device includes a housing and a rotating shaft. The housing is provided with a floating ring structure to prevent large-scale leakage of high-pressure gas from the machine. The floating ring structure includes a limiting ring for blocking the high-pressure gas from the machine. An acoustic emission sensor is provided on the outer wall of the housing for listening to the sound of the rotating shaft contacting the limiting ring. An elastic component is provided inside the housing to provide elastic support for the limiting ring. An air injection mechanism is installed on the housing to provide central support for the limiting ring through high-pressure gas. The air injection mechanism includes a sealing ring assembly for compensating for the gap between the limiting ring and the inner wall of the housing.

[0006] Preferably, the housing is a circular sleeve structure, and the rotating shaft is located at the center of the housing.

[0007] Preferably, the floating ring structure includes a dynamic pressure groove assembly installed on the inner wall of the limiting ring to prevent a large amount of high-pressure gas from leaking out. The limiting ring consists of an outer ring and an inner ring, and the dynamic pressure groove assembly is installed on the inner wall of the inner ring. The bottom end of the inner ring is provided with a stress relief groove to prevent deformation of the inner ring caused by deformation of the outer ring.

[0008] Preferably, the dynamic pressure trough assembly consists of a deep trough area, a shallow trough area, and a sealing dam. The deep trough area, the shallow trough area, and the sealing dam are respectively used to absorb high-pressure gas transmitted from the machine, to compress fluid to establish a local high-pressure peak, and to block compressed gas.

[0009] Preferably, the radial depth of the deep trench area is 20 μm to 50 μm, the radial depth of the shallow trench area is 5 μm to 15 μm, the depth ratio of the radial depth of the deep trench area to the radial depth of the shallow trench area is in the range of 2.5:1 to 4:1, and a stepped surface is formed at the junction of the shallow trench area and the sealing dam. The stepped surface is substantially perpendicular to the fluid flow direction to generate a fluid wedge effect.

[0010] Preferably, the air film between the smooth upper part of the sealing dam and the rotating shaft is a smooth damping strip, which is used to ensure the stable suspension of the limiting ring.

[0011] Preferably, the elastic component includes a mounting countersunk hole at the bottom of the outer ring, an annular base is fixedly installed on the inner wall of the housing, a strong spring is fixedly installed between the mounting countersunk hole and the annular base, and an anti-rotation groove is provided at the bottom of the outer ring to prevent the limiting ring from rotating, and an anti-rotation pin is fitted on the anti-rotation groove.

[0012] Preferably, the gas injection mechanism includes a limiting ring groove formed on the outer wall of the outer ring, a circular ring fixedly installed on the limiting ring groove, a rectangular through hole formed on the circular ring, and a gas injection port formed on the outer wall of the housing.

[0013] Preferably, an injection pipe is slidably installed on the injection port, the injection pipe is fixedly installed in the rectangular through hole, and the injection pipe can be offset on the injection port as the limiting ring rotates slightly. The inner wall of the limiting ring groove is provided with an air delivery hole that connects to the rotating shaft.

[0014] Preferably, the sealing ring assembly consists of an upper sealing ring and a lower sealing ring, and the upper and lower sealing rings, together with the housing and the limiting ring, form an annular air-proof cavity to prevent the high-pressure gas injected into the gas injection pipe from leaking out.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention forms a uniform air pressure support layer through an air injection mechanism, which enables the limiting ring to flexibly follow the movement of the rotating shaft and effectively compensate for the dynamic eccentricity and vibration of the rotating shaft.

[0016] 2. The present invention utilizes the dynamic pressure groove group of deep and shallow groove combination to generate a strong fluid wedge effect, forming a high-rigidity gas film, which helps to ensure the stability of the sealing gap and avoid direct contact wear.

[0017] 3. This invention effectively blocks the transmission of outer ring deformation to the inner ring sealing surface by combining an inner and outer ring split structure with a stress relief groove, which helps to ensure the roundness and sealing reliability of the inner ring hole at high temperatures. At the same time, by integrating an acoustic emission sensor, the contact signal between the floating ring and the rotating shaft can be monitored in real time to achieve early collision warning. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a floating ring damping sealing device proposed in this invention; Figure 2 This is a schematic diagram of the floating ring structure of a floating ring damping sealing device proposed in this invention; Figure 3 This is a schematic cross-sectional view of the structure of a floating ring damping sealing device proposed in this invention; Figure 4 This is a schematic diagram of the air injection mechanism structure of a floating ring damping sealing device proposed in this invention; Figure 5 This is a schematic cross-sectional view of the limiting ring groove of a floating ring damping sealing device proposed in this invention; Figure 6 This is a schematic diagram of the elastic component structure of a floating ring damping sealing device proposed in this invention.

[0019] In the diagram: 1. Shaft; 2. Housing; 3. Floating ring structure; 31. Outer ring; 32. Smooth damping band; 33. Sealing dam; 34. Deep groove area; 35. Shallow groove area; 36. Inner ring; 37. Stress relief groove; 4. Acoustic emission sensor; 5. Gas injection mechanism; 51. Upper sealing ring; 52. Lower sealing ring; 53. Gas injection port; 54. Rectangular through hole; 55. Circular ring; 56. Gas injection pipe; 57. Gas delivery hole; 58. Limiting ring groove; 59. Annular air isolation cavity; 6. Elastic component; 61. Anti-rotation groove; 62. Mounting countersunk hole; 63. Anti-rotation pin; 64. Strong spring; 7. Annular base. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Reference Figures 1-6 A floating ring damping sealing device includes a rotating shaft 1 assembled along its axis, a housing 2 having a cylindrical structure, typically fixed to the equipment casing by a flange or bolts, with an assembly space between its central hole and the rotating shaft 1, and a floating ring structure 3 serving as the main sealing element installed within this space.

[0022] An acoustic emission sensor 4 is preferably installed on the outer wall of the housing 2, near the high-pressure side or in an area expected to be prone to impact and friction. The acoustic emission sensor 4 can preferably be a piezoelectric or capacitive acoustic emission probe, which is tightly attached to the outer surface of the housing 2 by threaded connection or special clamp. It is used to collect and listen to the high-frequency stress wave signal, i.e., the acoustic emission signal, generated when there is microscopic or macroscopic contact and friction between the rotating shaft 1 and the inner ring 36. The sensor signal can be connected to an external analysis system to realize real-time monitoring of the sealing status and early collision warning.

[0023] The specific composition of the floating ring structure 3 and its design for solving the problem of thermal deformation are as follows: Figure 2 As shown, the floating ring structure 3 adopts an original split design, consisting of an outer ring 31 and an inner ring 36. The outer ring 31 serves as the load-bearing and connecting base, and its material must meet the following requirements: First, it must have high strength and high stiffness to withstand the continuous spring preload from the elastic component, the radial load generated by the air injection pressure, and the instantaneous impact load that may occur under extreme working conditions, ensuring that the structure does not undergo plastic deformation or instability.

[0024] Secondly, excellent thermal stability and creep resistance are required. Under wide temperature range conditions (e.g., from room temperature to several hundred degrees), the material should maintain stable mechanical properties, have a relatively controllable coefficient of thermal expansion, and have strong creep resistance under high stress and high temperature to prevent preload relaxation or failure of fit due to creep after long-term service.

[0025] Third, it has good processability and economy, making it easy to perform precision machining such as turning, milling, drilling and heat treatment to form complex structures such as limiting ring groove 58 and mounting countersunk hole 62, and has good weldability.

[0026] Therefore, the outer ring 31 can preferably be made of a metal material with high strength and good thermal stability, such as stainless steel or high-temperature alloy. The inner ring 36, as the component that directly forms a sealing pair with the rotating shaft 1, must have the following material requirements: First, excellent wear resistance and self-lubricating properties, which are fundamental to preventing adhesive wear and abrasive wear with the rotating shaft 1 and ensuring stable clearance during long-term operation. Even under momentary contact conditions where the gas film temporarily fails, the material itself must be able to resist wear to avoid "shaft seizure" accidents.

[0027] Secondly, a low and stable coefficient of friction helps reduce starting torque and frictional power consumption during operation, thereby improving efficiency.

[0028] Third, the extremely low coefficient of thermal expansion ensures that the sealing gap is controllable at high temperatures and prevents "thermal jamming".

[0029] Fourth, it has good thermal shock resistance and chemical stability: it can withstand the thermal shock caused by rapid start-up and shutdown, and does not react harmfully with the sealing medium (which may be high-temperature gas, steam or process gas).

[0030] Therefore, the inner ring 36 can preferably be made of a wear-resistant, self-lubricating material with a low coefficient of thermal expansion, such as impregnated graphite, silicon carbide, or special engineering ceramics.

[0031] The inner ring 36 is fitted into the inner hole of the outer ring 31 with an interference fit, forming a tight bond at room temperature. To address the deformation transmission problem caused by the difference in thermal expansion coefficients of materials and external thermal loads at high temperatures, an annular stress relief groove 37 is machined at the bottom of the inner ring 36, i.e., at the end of the mating surface with the outer ring 31. The axial depth and radial width of this groove are precisely calculated. Its function is to provide a space to accommodate the deformation when the outer ring 31 undergoes slight elastic or plastic deformation due to the influence of air injection pressure, assembly force, or uneven temperature field. This effectively prevents the deformation from being transmitted to the inner hole of the working sealing surface of the inner ring 36, thereby maintaining the roundness of the inner hole of the inner ring 36 even at high temperatures and preventing the leakage from worsening or jamming due to heat-induced loss of roundness.

[0032] like Figure 2 As shown, a set of circumferentially periodically distributed dynamic pressure grooves is precisely machined on the inner wall surface of the inner ring 36. This set of grooves is the core for generating the fluid dynamic pressure effect and forming a stable gas film. The dynamic pressure groove set is composed of three functional areas in sequence: deep groove area 34, shallow groove area 35, and sealing dam 33. The deep groove 34 serves as the gas inlet and initial containment area. Its radial depth is designed to be 20 μm to 50 μm, and its main function is to guide and contain the sealing gas flowing in from the high-pressure side.

[0033] The shallow groove region 35 serves as a gas compression zone. Its radial depth is significantly reduced, designed to be between 5 μm and 15 μm. The depth ratio of the deep groove region 34 to the shallow groove region 35 is controlled within the range of 2.5:1 to 4:1. When the shaft 1 rotates at high speed, gas is drawn from the deep groove region 34 into the shallow groove region 35. Due to the rapid contraction of the flow channel cross-sectional area, the gas is strongly compressed, and the pressure increases significantly.

[0034] The sealing dam 33 serves as a high-pressure gas film formation zone. This is a smooth, ungrooved ring on the inner wall. Compressed gas accumulates in the sealing dam 33 region, forming a localized high-pressure zone. The key design feature is the steep, essentially perpendicular step surface perpendicular to the airflow direction formed at the junction of the shallow groove region 35 and the sealing dam 33. This structure generates a strong "fluid wedge effect," converting the rotating tangential flow into a normal pressure with high load-bearing capacity, thereby forming a highly rigid gas film between the sealing dam 33 and the rotating shaft 1.

[0035] Additionally, a smooth damping band 32 is included. Located upstream of the sealing dam 33 near the high-pressure side, the inner wall of the inner ring 36 maintains a smooth surface, and the gap between the smooth damping band 32 and the rotating shaft 1 forms the smooth damping band 32. This region further stabilizes the flow, assists in the homogenization of the gas film, and works in conjunction with the dynamic pressure trough assembly to ensure the stable suspension of the floating ring.

[0036] It should be noted that the deep groove zone 34, with a depth of 20-50μm, provides sufficient initial volume to ensure that enough gas is sheared and carried into the sealing area by the rotating shaft 1. When the gas enters the shallow groove zone 35, with a depth of 5-15μm, the flow height drops sharply to the original 2.5:1 to 4:1, forming a strong geometric constraint. In addition, the above design can optimize the compression ratio. Within the above depth ratio range, a sufficiently large local compression ratio can be generated, thereby establishing a local high pressure peak at the end of the shallow groove zone 35 that far exceeds the ambient pressure. This is the basis for forming a high-rigidity gas film.

[0037] This also helps prevent flow separation. If the depth ratio is too large (e.g., >5:1), the cross-sectional contraction will be too severe, which may lead to airflow separation and vortices, resulting in unstable flow and pressure pulsation, which in turn undermines the stability of the air film. If the depth ratio is too small (e.g., <2:1), the compression effect will be insufficient, and the dynamic lift will be limited.

[0038] It should be added that the lower limit setting (34 ≥ 20 μm for deep groove area, 35 ≥ 5 μm for shallow groove area): Considering the economy of micro-machining processes (such as precision grinding, laser processing or micro-electrical discharge machining), setting the lower limit of depth at this level can ensure that the groove shape can be formed stably and accurately in mass production, and will not completely lose its function due to processing errors (usually within ±2-5 μm).

[0039] Upper limit setting (deep groove area 34≤50μm, shallow groove area 35≤15μm): excessively deep grooves will bring multiple problems. First, they will weaken the structural strength and rigidity of the inner ring 36, which may exacerbate deformation, especially under high temperature and high pressure. Second, they will increase ineffective leakage channels, and the leakage may increase under non-design conditions (such as low speed). Third, during the start-up and shutdown phases, the excessively large groove volume requires a longer time to build up pressure, which is not conducive to the rapid formation of an effective gas film.

[0040] like Figures 3-6As shown, the air injection mechanism 5 includes an annular limiting groove 58 machined on the outer cylindrical surface of the outer ring 31. The inner wall of the limiting groove 58 has air delivery holes 57 communicating with the rotating shaft 1, and several air delivery holes 57 are arranged circumferentially. A circular ring 55 is fixedly installed in the limiting groove 58 by interference fit or fasteners. A rectangular through hole 54 is provided on the circular ring 55, and one end of an air injection pipe 56 is sealed and fixed in the rectangular through hole 54 by welding, threading, or crimping.

[0041] On the side wall of the housing 2, corresponding to the position of the air injection pipe 56, an air injection port 53 is opened. The diameter of the air injection port 53 is slightly larger than the outer diameter of the air injection pipe 56, and the two form a clearance fit, allowing the air injection pipe 56 together with the entire floating ring structure 3 to float in a radially limited floating space, while ensuring the air passage is connected. An external air source is connected to the outside of the air injection port 53 through a flexible pipeline to continuously inject the high-pressure gas after pressure regulation.

[0042] In the annular space between the inner wall of the housing 2 and the outer wall of the outer ring 31, a sealing ring is installed at the top and a sealing ring at the bottom, namely the upper sealing ring 51 and the lower sealing ring 52. The sealing rings can preferably be O-rings. The two sealing rings, together with the inner wall of the housing 2 and the outer wall of the outer ring 31, form a closed annular air-tight cavity 59.

[0043] High-pressure gas injected through the injection pipe 56 fills the annular air-barrier cavity 59, forming a uniform and adjustable air-bearing pressure field around the outer periphery of the floating ring. This pressure field generates a radial resultant force pointing towards the center of the rotating shaft 1, achieving "active air-bearing alignment" of the floating ring and effectively compensating for the dynamic eccentricity of the rotating shaft 1.

[0044] The elastic component 6 includes a mounting countersunk hole 62 machined on the end face of the outer ring 31, and an annular base 7 fixedly installed inside the housing 2. A strong spring 64 is placed between the mounting countersunk hole 62 and the annular base 7 to provide initial preload and support in the absence of air or low pressure.

[0045] To prevent the floating ring from rotating under the influence of circumferential airflow, an anti-rotation groove 61, such as an oblong groove, is provided on the same end face of the outer ring 31. Correspondingly, an anti-rotation pin 63 is fixed on the annular base 7. The anti-rotation pin 63 is inserted into the anti-rotation groove 61, and there is a sufficient gap in the radial direction between the anti-rotation pin 63 and the anti-rotation groove 61 to ensure that the floating ring can float freely in the radial direction, but is restricted from circumferential rotation.

[0046] It should be noted that the specific model and specifications of the acoustic emission sensor 4 need to be selected and determined based on the actual specifications of the device. The specific selection and calculation method adopts the existing technology in this field, so it will not be elaborated here.

[0047] The functional principle of this invention can be explained through the following operational methods: First, before the device is started, the floating ring structure 3 is pre-tightened and held in an initial central position by the strong spring 64 of the elastic component 6, in preparation for operation.

[0048] When the equipment starts operating, external high-pressure gas is injected into the annular air-tight chamber 59 through the gas injection pipe 56. The gas pressure acts uniformly on the outer circumference of the outer ring 31 of the floating ring, forming an air-floating pressure field with active centering function. This pressure field generates a radial restoring force pointing towards the center of the rotating shaft 1, pushing the entire floating ring structure 3 to overcome part of the spring preload, achieving initial suspension and centering, thereby effectively compensating for the initial static eccentricity or slow displacement of the rotating shaft 1.

[0049] Subsequently, the rotating shaft 1 rotates at high speed, driving the sealing gas into the dynamic pressure grooves machined on the inner wall of the inner ring 36. The gas first enters the deep groove area 34 and is guided and contained; then it flows into the shallow groove area 35. Due to the rapid contraction of the flow channel cross-sectional area, the gas is strongly compressed, and the pressure increases significantly; finally, the compressed gas accumulates in the sealing dam 33 area. The vertical step surface formed at the junction of the shallow groove area 35 and the sealing dam 33 generates a strong fluid wedge effect, converting the shear flow of the fluid into a strong normal pressure, thereby forming a high-stiffness dynamic pressure gas film between the sealing dam 33 and the rotating shaft 1. At the same time, the smooth damping band 32 further stabilizes the flow. This dynamic pressure gas film, in conjunction with the aforementioned static pressure buoyancy, enables the floating ring to obtain high dynamic stiffness and positioning accuracy, maintaining a stable and uniform micron-level sealing gap.

[0050] Meanwhile, the high-strength spring 64 not only provides support in the airless state, but also acts as a compressible damping element during operation, absorbing the high-frequency micro-amplitude vibrations of the system. The cooperation between the anti-rotation pin 63 and the anti-rotation groove 61 ensures that the floating ring can only perform the required radial translation without generating harmful circumferential rotation, which helps to ensure the directionality and stability of the fluid effect of the hydrodynamic tank assembly.

[0051] During dynamic operation, when the rotating shaft 1 experiences a momentary radial jump due to disturbance, the dynamic following and gap adaptive adjustment mechanism is triggered. The local change in the sealing gap causes an instantaneous redistribution of the air film pressure at that point, generating a huge reverse restoring force that drives the floating ring structure 3 to instantaneously follow the movement of the rotating shaft 1. During this process, the air injection pipe 56 slides within the air injection port 53, and the upper sealing ring 51 and lower sealing ring 52 undergo elastic deformation, but the sealing of the annular air-tight cavity 59 is maintained, ensuring the continuity of the air-bearing support. The entire floating ring acts like a mass block supported by both the air film and springs, contributing to the adaptive and precise following of the movement of the rotating shaft 1.

[0052] Finally, the acoustic emission sensor 4 continuously monitors and collects high-frequency stress wave signals generated by any abnormal contact or friction between the rotating shaft 1 and the inner ring 36 of the floating ring. Once a specific acoustic emission characteristic indicating friction is detected, the system can immediately sound an alarm, enabling online monitoring of the sealing status and early fault warning, which helps improve the reliability and maintainability of the device.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A floating ring damping sealing device, comprising a housing (2) and a rotating shaft (1), characterized in that, The housing (2) is provided with a floating ring structure (3) for preventing a large amount of high-pressure gas from leaking out of the machine. The floating ring structure (3) includes a limiting ring for blocking the high-pressure gas inside the machine. The outer wall of the housing (2) is provided with an acoustic emission sensor (4) for listening to the sound of the shaft (1) contacting the limiting ring. The housing (2) is provided with an elastic component (6) for providing elastic support for the limiting ring. The housing (2) is provided with an air injection mechanism (5) for providing central support for the limiting ring through high-pressure gas. The air injection mechanism (5) includes a sealing ring group for compensating the gap between the limiting ring and the inner wall of the housing (2).

2. The floating ring damping sealing device according to claim 1, characterized in that, The housing (2) is a circular sleeve structure, and the rotating shaft (1) is located at the center of the housing (2).

3. The floating ring damping sealing device according to claim 2, characterized in that, The floating ring structure (3) includes a dynamic pressure groove assembly installed on the inner wall of the limiting ring to prevent a large amount of high-pressure gas from leaking out. The limiting ring is composed of an outer ring (31) and an inner ring (36), and the dynamic pressure groove assembly is installed on the inner wall of the inner ring (36). The bottom end of the inner ring (36) is provided with a stress relief groove (37) to prevent the deformation of the outer ring (31) from causing the inner ring (36) to deform.

4. A floating ring damping sealing device according to claim 3, characterized in that, The dynamic pressure tank group consists of a deep tank area (34), a shallow tank area (35), and a sealing dam (33). The deep tank area (34), the shallow tank area (35), and the sealing dam (33) are used to absorb the high-pressure gas transmitted from the machine, to compress the fluid to establish a local high-pressure peak, and to block the compressed gas, respectively.

5. A floating ring damping sealing device according to claim 4, characterized in that, The radial depth of the deep trench (34) is 20 μm to 50 μm, the radial depth of the shallow trench (35) is 5 μm to 15 μm, the depth ratio of the radial depth of the deep trench (34) to the radial depth of the shallow trench (35) is in the range of 2.5:1 to 4:1, and a stepped surface is formed at the junction of the shallow trench (35) and the sealing dam (33), the stepped surface being substantially perpendicular to the fluid flow direction to generate a fluid wedge effect.

6. A floating ring damping sealing device according to claim 5, characterized in that, The air film between the smooth part at the upper end of the sealing dam (33) and the rotating shaft (1) is a smooth damping band (32), which is used to ensure the stable suspension of the limiting ring.

7. A floating ring damping sealing device according to claim 4, characterized in that, The elastic component (6) includes a mounting countersunk hole (62) at the bottom of the outer ring (31), an annular base (7) is fixedly installed on the inner wall of the housing (2), a strong spring (64) is fixedly installed between the mounting countersunk hole (62) and the annular base (7), and an anti-rotation groove (61) is provided at the bottom of the outer ring (31) to prevent the limiting ring from rotating, and an anti-rotation pin (63) is fitted on the anti-rotation groove (61).

8. A floating ring damping sealing device according to claim 7, characterized in that, The gas injection mechanism (5) includes a limiting ring groove (58) opened on the outer wall of the outer ring (31), a circular ring (55) is fixedly installed on the limiting ring groove (58), a rectangular through hole (54) is opened on the circular ring (55), and a gas injection port (53) is opened on the outer wall of the housing (2).

9. A floating ring damping sealing device according to claim 8, characterized in that, An air injection pipe (56) is slidably installed on the air injection port (53). The air injection pipe (56) is fixedly installed in the rectangular through hole (54). The air injection pipe (56) can be offset on the air injection port (53) as the limiting ring rotates slightly. An air delivery hole (57) communicating with the rotating shaft (1) is opened on the inner wall of the limiting ring groove (58).

10. A floating ring damping sealing device according to claim 9, characterized in that, The sealing ring assembly consists of an upper sealing ring (51) and a lower sealing ring (52), and the upper sealing ring (51) and the lower sealing ring (52) together with the housing (2) and the limiting ring form an annular air-proof cavity (59) to prevent the high-pressure gas injected into the gas injection pipe (56) from leaking out.

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