Dry gas seal ring and dry gas seal structure

Abstract

The utility model discloses a kind of dry gas seal ring and dry gas seal structure, it is related to dry gas seal technical field.The dry gas seal ring and dry gas seal structure, including dynamic ring and static ring, spiral groove is opened in the dynamic ring sealing end face, and the sealing end face outer edge of dynamic ring is equipped with a circle non-work area micro boss ring, micro boss ring is located outside spiral groove area, is formed by super-precision grinding, for preferentially contacting static ring surface in start-stop stage, avoid spiral groove area direct participation in friction.The utility model is matched with the design of dynamic ring micro boss ring and static ring buffer contact zone, in combination with pressure relief transition zone, micro-scale spiral gradual groove and the circumferential corrugated structure of elastic buffer ring, realize start-stop low friction, gas film fast response and dynamic compensation, and gradient hardness matching and solid lubricating layer are used to improve wear resistance, improve the reliability and service life of dry gas seal under frequent start-stop working condition.

Description

Technical Field

[0001] This utility model relates to the field of dry gas sealing technology, and in particular to a dry gas sealing ring and a dry gas sealing structure. Background Technology

[0002] Dry gas seals, as a non-contact shaft end sealing technology, are widely used in high-speed rotating equipment such as centrifugal compressors, pumps, and turbines. They achieve a sealing effect of zero or minimal leakage of the medium by forming a stable gas film between the sealing end faces of the rotating and stationary rings.

[0003] Under normal operating conditions, the spiral groove structure on the end face of the rotating ring can generate a hydrodynamic pressure effect, causing the sealing end face to disengage and achieve wear-free operation. However, during equipment startup, shutdown, or transient low-speed operation, the gas film has not yet been established or has already ruptured, and the rotating ring and stationary ring are in dry contact or boundary lubrication state, which can easily lead to end face wear, thermal cracking, or even adhesion failure. Utility Model Content

[0004] To achieve the above objectives, this application provides a dry gas sealing ring, including a rotating ring and a stationary ring. The rotating ring has a spiral groove on its sealing end face, and a non-working area micro-protrusion ring is provided on the outer edge of the sealing end face of the rotating ring. The micro-protrusion ring is located outside the spiral groove area and is formed by ultra-precision grinding. It is used to preferentially contact the surface of the stationary ring during the start-up and shutdown phases, so as to avoid the spiral groove area from directly participating in friction.

[0005] Preferably, an annular buffer contact strip is provided at the edge of the sealing end face of the stationary ring, and the buffer contact strip is lower than the main sealing end face of the stationary ring.

[0006] Preferably, the stationary ring is a composite structure, including a metal base and elastic buffer rings that can be detachably installed at both ends of the metal base.

[0007] Preferably, the inner ring of the elastic buffer ring has a circumferential corrugated structure, which generates elastic deformation when the elastic buffer ring is axially compressed, allowing for local micro-motion compensation.

[0008] Preferably, the surface of the elastic buffer ring is coated with a solid lubricating layer with a thickness of 2~5μm.

[0009] Preferably, the stationary ring is disposed inside the mounting base, and a sealing ring is provided on the end face of the mounting base and the stationary ring.

[0010] Preferably, a pressure relief transition area is provided between the spiral groove area of ​​the dynamic ring sealing end face and the outer edge micro-protrusion ring, and the pressure relief transition area is a groove-free flat area.

[0011] Preferably, the outer edge of the sealing end face of the moving ring is provided with a micro-scale spiral gradient groove, which is located outside the spiral groove area and is not connected to the spiral groove, and the spiral direction is consistent with the spiral groove.

[0012] Preferably, the end face pairing of the moving ring and the stationary ring adopts a gradient hardness matching design, where the hardness of the moving ring end face is greater than the hardness of the buffer contact strip of the stationary ring, forming a soft contact pairing.

[0013] Preferably, in another aspect, this application also provides a dry gas sealing structure, including the dry gas sealing ring described in any one of the above, including a bushing, an elastic support member and a sealing shell. The sealing shell is provided with an air inlet for connecting to an external air supply system. A mounting base is fixed inside the sealing shell to form a stationary component. The stationary ring is axially positioned and installed in the mounting base, and its circumferential rotation is restricted by an anti-rotation structure. The bushing is sleeved on the rotating shaft and rotates synchronously with the rotating shaft to form a rotating component. The moving ring is fixedly installed at the end of the bushing, and its sealing end face is opposite to the sealing end face of the stationary ring to form an end face sealing pair. On the side of the moving ring away from the sealing end face, the bushing is provided with an elastic support member.

[0014] This utility model provides a dry gas sealing ring and dry gas sealing structure, which, compared with the prior art:

[0015] 1. This utility model constructs a low-friction contact mechanism during the start-up and shutdown phases by setting a non-working area micro-protrusion ring on the outer edge of the sealing end face of the dynamic ring, and cooperating with the annular buffer contact strip on the edge of the stationary ring end face. During the start-up and shutdown process, the micro-protrusion ring preferentially contacts the buffer contact strip of the stationary ring to achieve a "point-ring" type local contact, reducing the contact area and frictional torque, and effectively avoiding direct friction and damage to the spiral groove area in the absence of an air film. At the same time, the dynamic ring end face is provided with a pressure relief transition area and a micro-scale spiral gradient groove, which not only blocks the interference of external airflow back pressure, but also generates a weak dynamic pressure effect when rotating at low speed, promoting the rapid formation of the initial air film and improving the reliability of the seal start-up. The stationary ring adopts a composite structure, and its elastic buffer ring has a built-in circumferential corrugated structure, which can generate elastic deformation when subjected to axial pressure, compensating for installation deviations and shaft movement, ensuring uniform end face fit, and further reducing the risk of wear.

[0016] 2. This utility model adopts a gradient hardness matching end face pairing design. The hardness of the dynamic ring end face is higher than that of the static ring buffer contact strip, forming a "hard and soft" contact pair. This not only ensures the structural strength of the dynamic ring, but also gives the static ring contact strip better anti-adhesion and self-lubricating properties during start-stop friction. Combined with the solid lubricating layer coated on the surface, it extends the service life of the sealing ring under dry friction conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0019] Figure 2 This is a top view of the overall structure of an embodiment of the present utility model;

[0020] Figure 3 This is an embodiment of the present utility model. Figure 2 Schematic diagram of the structural section along point AA;

[0021] Figure 4 This is a schematic diagram of the sealing shell structure according to an embodiment of the present utility model;

[0022] Figure 5 This is a schematic diagram showing the disassembled structure of the rotating ring and bushing according to an embodiment of the present utility model;

[0023] Figure 6 This is a schematic diagram of the dynamic ring structure according to an embodiment of the present utility model;

[0024] Figure 7 This is a cross-sectional view of the mounting base structure according to an embodiment of the present utility model;

[0025] Figure 8 This is a schematic diagram of the stationary ring structure according to an embodiment of the present invention.

[0026] icon:

[0027] 1. Sealing shell; 2. Rotating shaft; 3. Air inlet; 4. Bushing; 5. Moving ring; 51. Spiral groove; 52. Micro-protrusion ring; 53. Micro-scale spiral gradient groove; 6. Elastic support; 7. Mounting base; 8. Sealing ring; 9. Stationary ring; 91. Metal base; 92. Elastic buffer ring; 93. Corrugated structure; 94. Buffer contact strip. Detailed Implementation

[0028] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] Please refer to Figures 1 to 8This utility model provides a dry gas sealing ring, including a dynamic ring 5 and a stationary ring 9, which together form an end face sealing pair. During operation, non-contact sealing is achieved through an air film, and friction and wear are reduced by optimizing the contact mechanism during the start-up and shutdown phases.

[0030] The moving ring 5 is a rotary sealing element, usually made of high hardness and high wear resistance materials, such as silicon carbide, tungsten carbide or reaction sintered silicon carbide, and its side facing the stationary ring 9 is the sealing end face.

[0031] A spiral groove 51 is provided on the sealing end face. The spiral groove 51 is distributed in the form of an Archimedean or logarithmic spiral, with a depth of 5 to 10 μm and a width of 0.2 to 0.6 mm. The spiral direction is consistent with the normal rotation direction of the equipment. When the rotating ring 5 rotates at high speed with the shaft, the spiral groove 51 generates a hydrodynamic pressure effect, pumping gas into the sealing gap to form a stable gas film and realize non-contact operation.

[0032] like Figure 6 As shown, a non-working micro-protrusion ring 52 is provided on the outer edge of the sealing end face of the rotating ring 5. It is located radially outside the spiral groove 51 and does not participate in the air film bearing under normal working conditions. The micro-protrusion ring 52 is integrally formed by ultra-precision grinding process, with a height of 0.8 to 2 μm and a width of 0.15 to 0.5 mm. During the equipment start-up or shutdown process, the air film has not yet been established or has been ruptured. The elastic pre-tightening force causes the rotating ring 5 to fit against the stationary ring 9. At this time, the micro-protrusion ring 52 preferentially contacts the end face of the stationary ring 9 to form a local support point, avoiding the spiral groove 51 area from directly participating in dry friction and effectively protecting the main sealing surface.

[0033] Furthermore, a pressure relief transition zone is provided between the spiral groove 51 area and the micro-protrusion ring 52. The pressure relief transition zone is a groove-free flat area without any groove treatment. The surface is kept in its original ground flat state, and the width is 0.2 to 0.6 mm. Its function is to block the reverse flow of external ambient gas to the main sealing area, prevent the formation of a local high pressure area due to reverse pumping of gas, and prevent the sealing surface from sticking together. At the same time, it serves as a geometric transition zone to avoid stress concentration.

[0034] In addition, a micro-scale spiral gradient groove 53 is provided in the outer edge region of the moving ring 5. It is independent of the spiral groove 51 and is not connected to it. It is distributed in 1 to 3 short spiral segments with a groove depth of 1 to 3 μm and a groove width of 50 to 150 μm. The direction of rotation is the same as that of the spiral groove 51. During the low-speed start-up stage, the micro-scale spiral gradient groove 53 can generate a weak dynamic pressure effect, actively guide the gas into the sealing gap, promote the rapid formation of the initial gas film, realize soft start, and reduce the start-stop friction torque.

[0035] like Figure 8As shown, the stationary ring 9 is a stationary sealing element installed in the sealing cavity and does not rotate with the shaft. In this embodiment, the stationary ring 9 adopts a composite structure design, including a metal base 91 and elastic buffer rings 92 that can be detachably installed at both ends. The metal base 91 is usually made of stainless steel or nickel-based alloy, providing structural strength and installation reference. The elastic buffer ring 92 is made of carbon graphite, metal-impregnated carbon or ceramic matrix composite material, which has good self-lubricating properties and thermal stability.

[0036] The elastic buffer ring 92 is fixed to the metal base 91 by an interference fit or a slot structure, which facilitates replacement and maintenance. The inner ring of the elastic buffer ring 92 is provided with a circumferential corrugated structure 93. The corrugated structure 93 has a continuous wave-shaped cross section, which can generate elastic compression deformation when subjected to axial pressure, allowing axial displacement compensation of 0.05 to 0.2 mm. It effectively absorbs the end face misalignment caused by installation errors, shaft movement and thermal expansion, and ensures that the sealing pair can still maintain uniform fit under dynamic conditions, avoiding high stress wear at the edges.

[0037] At the position corresponding to the micro-protrusion ring 52 of the moving ring 5 on the sealing end face edge of the stationary ring 9, an annular buffer contact band 94 is provided. After precision machining, the axial height of the annular buffer contact band 94 is 0.3 to 0.7 μm lower than the main sealing end face of the stationary ring 9, forming a stepped sinking structure. During the start-up and shutdown phase, the micro-protrusion ring 52 of the moving ring 5 first contacts the buffer contact band 94, realizing the "point-to-surface" contact transition mechanism - that is, initially a small-area point contact or narrow ring contact, gradually transitioning to full contact as the load increases, thereby significantly reducing the frictional initiation torque and preventing adhesion.

[0038] To enhance the anti-wear performance during the start-stop phase, the surface of the elastic buffer ring 92 is coated with a solid lubricating layer, preferably a molybdenum disulfide, tungsten disulfide, or diamond-like carbon coating, with a thickness controlled between 2 and 5 μm. This coating can still provide effective lubrication under conditions of no lubrication or low-speed dry friction, significantly extending the service life of the sealing ring.

[0039] Furthermore, the end face pairing of the dynamic ring 5 and the stationary ring 9 adopts a gradient hardness matching design: the end face hardness of the dynamic ring 5 is HRA 85-92, while the hardness of the buffer contact strip 94 of the stationary ring 9 is HRA 60-75, forming a "hard-soft" contact pair. This not only ensures the structural rigidity and wear resistance of the dynamic ring 5, but also gives the stationary ring 9 better compliance and anti-adhesion ability during the contact process, reducing the risk of cold welding and scratches, and achieving "soft contact" protection during the start-up and shutdown process.

[0040] The stationary ring 9 is installed inside the mounting base 7, which is fixed in the sealing shell 1, forming a stationary component. A sealing ring 8, preferably an O-ring or perfluoroether rubber ring, is provided between the mounting base 7 and the axial end face of the stationary ring 9 to block the leakage path of the process medium along the outer circumference of the stationary ring 9, ensuring that the axial positioning of the stationary ring 9 is reliable and the seal is tight. At the same time, the mounting base 7 is provided with an anti-rotation pin or keyway structure to restrict the circumferential rotation of the stationary ring 9 and ensure that it maintains a fixed posture during operation.

[0041] On the other hand, such as Figure 3 As shown, this application also provides a dry gas sealing structure for a dry gas sealing ring, including a bushing 4, an elastic support 6, and a sealing shell 1. The sealing shell 1 is provided with an air inlet 3 for connecting to an external air supply system. A mounting base 7 is fixed inside the sealing shell 1 to form a stationary component. The stationary ring 9 is axially positioned and installed in the mounting base 7, and its circumferential rotation is restricted by an anti-rotation structure. The bushing 4 is sleeved on the rotating shaft 2 and rotates synchronously with the rotating shaft 2 to form a rotating component. The moving ring 5 is fixedly installed at the end of the bushing 4, and its sealing end face is opposite to the sealing end face of the stationary ring 9 to form an end face sealing pair. On the side of the moving ring 5 away from the sealing end face, the bushing 4 is provided with an elastic support 6.

[0042] In summary, when the equipment is running, the moving ring 5 rotates with the shaft, the spiral groove 51 pumps gas to form a gas film, the moving ring 5 is lifted and separated from the stationary ring 9, and enters a non-contact operation state. When starting or stopping, the micro-protrusion ring 52 and the buffer contact band 94 make priority contact. Combined with the early dynamic pressure effect of the micro-scale spiral gradient groove 53 and the axial compensation capability of the elastic buffer ring 92, a smooth transition with low friction and low wear is achieved.

[0043] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dry gas sealing ring, characterized in that: It includes a moving ring (5) and a stationary ring (9). The moving ring (5) has a spiral groove (51) on its sealing end face. The outer edge of the sealing end face of the moving ring (5) has a non-working area micro-protrusion ring (52). The micro-protrusion ring (52) is located outside the spiral groove (51) area and is formed by ultra-precision grinding. It is used to preferentially contact the surface of the stationary ring (9) during the start-up and stop phases to avoid the spiral groove (51) area from directly participating in friction.

2. The dry gas sealing ring according to claim 1, characterized in that: The sealing end face edge of the stationary ring (9) is provided with an annular buffer contact strip (94), which is lower than the main sealing end face of the stationary ring (9).

3. The dry gas sealing ring according to claim 2, characterized in that: The stationary ring (9) is a composite structure, including a metal base (91) and elastic buffer rings (92) that can be detachably installed at both ends of the metal base (91).

4. The dry gas sealing ring according to claim 3, characterized in that: The inner ring of the elastic buffer ring (92) is provided with a circumferential corrugated structure (93), which generates elastic deformation when the elastic buffer ring (92) is axially compressed, allowing for local micro-motion compensation.

5. The dry gas sealing ring according to claim 4, characterized in that: The surface of the elastic buffer ring (92) is coated with a solid lubricating layer with a thickness of 2~5μm.

6. The dry gas sealing ring according to claim 5, characterized in that: The stationary ring (9) is located inside the mounting base (7), and the end faces of the mounting base (7) and the stationary ring (9) are provided with sealing rings (8).

7. The dry gas sealing ring according to claim 1, characterized in that: The spiral groove (51) area of ​​the sealing end face of the moving ring (5) and the outer edge micro-protrusion ring (52) are provided with a pressure relief transition area, which is a grooveless flat area.

8. The dry gas sealing ring according to claim 7, characterized in that: The outer edge of the sealing end face of the moving ring (5) is provided with a micro-scale spiral gradient groove (53). The micro-scale spiral gradient groove (53) is located outside the region of the spiral groove (51) and is not connected to the spiral groove (51). Its spiral direction is consistent with that of the spiral groove (51).

9. The dry gas sealing ring according to claim 8, characterized in that: The end face pairing of the moving ring (5) and the stationary ring (9) adopts a gradient hardness matching design. The hardness of the end face of the moving ring (5) is greater than the hardness of the buffer contact strip (94) of the stationary ring (9), forming a soft contact pairing.

10. A dry gas sealing structure, comprising the dry gas sealing ring according to any one of claims 1-9, characterized in that: The assembly includes a bushing (4), an elastic support (6), and a sealing shell (1). The sealing shell (1) is provided with an air inlet (3) for connecting to an external air supply system. The mounting base (7) is fixed inside the sealing shell (1) to form a stationary assembly. The stationary ring (9) is axially positioned in the mounting base (7) and its circumferential rotation is restricted by an anti-rotation structure. The bushing (4) is sleeved on the rotating shaft (2) and rotates synchronously with the rotating shaft (2) to form a rotating assembly. The moving ring (5) is fixedly installed at the end of the bushing (4), and its sealing end face is set opposite to the sealing end face of the stationary ring (9) to form an end face sealing pair. On the side of the moving ring (5) away from the sealing end face, the bushing (4) is provided with an elastic support (6).

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