Mechanical sealing device

Abstract

The utility model discloses a mechanical sealing device, and belongs to the technical field of fluid sealing. The device comprises a sealing ring, wherein a plurality of similar V-shaped dynamic pressure grooves and upstream pumping grooves are formed in the sealing end face of the sealing ring; the dynamic pressure groove comprises a first side wall face and a second side wall face which are opposite in the circumferential direction of the sealing ring, a distance is formed between the radial outer ends of the first side wall face and the second side wall face, and the width between the first side wall face and the second side wall face is gradually increased from outside to inside and then gradually decreased in the radial direction of the sealing end face. The upstream pumping groove comprises a third side wall face and a fourth side wall face which are opposite in the circumferential direction of the sealing ring, the radial inner end of the third side wall face and the radial inner end of the fourth side wall face are spaced, and the width between the third side wall face and the fourth side wall face is gradually increased from inside to outside and then gradually decreased in the radial direction of the sealing end face. The mechanical seal can effectively reduce abrasion and leakage of a sealing end face, and is suitable for nuclear main pumps and mechanical seals in other industries.

Description

Technical Field

[0001] The utility model relates to the technical field of fluid sealing, in particular to a mechanical sealing device for a nuclear main pump. Background Art

[0002] As a clean and efficient energy source, nuclear energy plays a vital role in the global energy mix. The nuclear reactor's main coolant pump ("main pump") is the only large rotating equipment in a nuclear power plant's primary circuit and is often referred to as the "heart" of the circuit. The main pump shaft seal is a critical component within the primary circuit's pressure-bearing boundary. It not only faces complex operating conditions such as high-temperature, high-pressure media, large-scale friction, and multiphase flow, but also requires stable and controllable leakage over long, continuous operating cycles.

[0003] The groove structure is crucial in the design of mechanical seals. It determines the fluid dynamics behavior between the sealing end faces, which directly affects the sealing performance. A reasonable groove design can promote the formation of a stable lubricating film on the sealing end faces, effectively reducing direct contact friction, reducing wear, and extending the life of the seal. In addition, the groove shape also affects the leakage rate of the seal. A good groove design can ensure extremely low leakage under various working conditions and meet the strict requirements of industrial applications for sealing performance. The design of the groove structure also involves thermal management. The appropriate groove shape helps to disperse and transfer heat, preventing the sealing end faces from being damaged due to excessive temperatures. Therefore, the design of the groove structure is a key factor in achieving high efficiency, high reliability and long life of mechanical seals.

[0004] In engineering, spiral grooves, T-grooves and other structures are generally used to generate end face fluid dynamic pressure effects, allowing the seal to maintain non-contact operation at high speeds. In order to reduce leakage, engineers sometimes set up upstream pumping grooves on the side of the medium leakage to play the role of reverse pumping, achieving low leakage or even zero leakage. In addition, in some cases, a combination of deep and shallow groove dynamic pressure seals are used. The depth of the deep groove is at the millimeter level, and the depth of the shallow groove is at the micron level. When the seal is running at high speed, the thermal deformation induced by the deep groove causes the sealing end face to form a certain taper. Combined with the fluid dynamic pressure effect induced by the shallow groove, the opening force of the sealing end face can be increased. Under low speed conditions, fluid static pressure seals are often used. At this time, the sealing end face has no groove structure, and the taper of the end face is used to produce the fluid static pressure effect to achieve end face opening. Utility Model Content

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide a mechanical seal device with a new structure that can effectively reduce friction, wear and leakage of the sealing end face over the entire speed range, and is suitable for mechanical seals in nuclear main pumps and other industries.

[0006] According to an embodiment of the present invention, the mechanical sealing device comprises a sealing ring, wherein a sealing end surface of the sealing ring is provided with a plurality of V-shaped dynamic pressure grooves and a plurality of V-shaped upstream pumping grooves;

[0007] wherein a plurality of the dynamic pressure grooves are distributed at intervals along the circumferential direction of the sealing ring on the outer side of the sealing end surface, and the directions of the plurality of dynamic pressure grooves are consistent in the circumferential direction of the sealing ring; each of the dynamic pressure grooves comprises a first side wall surface and a second side wall surface that are opposite to each other in the circumferential direction of the sealing ring, wherein the radial outer ends of the first side wall surface and the second side wall surface are located on the outer circumferential surface of the sealing ring, and there is a distance between the radial outer ends of the first side wall surface and the second side wall surface, and the width between the first side wall surface and the second side wall surface gradually increases from the outside to the inside in the radial direction of the sealing end surface and then gradually decreases until the radial inner ends of the first side wall surface and the second side wall surface intersect to form a first sharp angle;

[0008] The plurality of upstream pumping grooves are distributed at intervals along the circumference of the sealing ring on the inner side of the sealing end face and correspond to the plurality of dynamic pressure grooves in the radial direction. The directions of the plurality of upstream pumping grooves are consistent in the circumferential direction of the sealing ring and are opposite to the directions of the plurality of dynamic pressure grooves. Each of the upstream pumping grooves includes a third side wall surface and a fourth side wall surface that are opposite to each other in the circumferential direction of the sealing ring. The radial inner ends of the third side wall surface and the fourth side wall surface are located on the inner circumferential surface of the sealing ring and there is a spacing between the radial inner ends of the third side wall surface and the fourth side wall surface. The width between the third side wall surface and the fourth side wall surface gradually increases from the inside to the outside in the radial direction of the sealing end face and then gradually decreases until the radial outer ends of the third side wall surface and the fourth side wall surface intersect to form a second sharp angle.

[0009] According to the mechanical sealing device of the embodiment of the utility model, when the sealing ring is in operation, the rotation direction of the sealing ring is opposite to the direction of the dynamic pressure groove; when the speed of the sealing ring is very low, the hydrostatic pressure effect formed on the sealing end face will cause the sealing end face to open, reducing friction and wear under low speed conditions; when the speed of the sealing ring is high, in the process of the sealing medium flowing from the outer diameter to the inner diameter of the sealing ring, the sealing medium first passes through the dynamic pressure groove, and the groove area of the dynamic pressure groove passed by it changes from narrow to wide and then from wide to narrow, and the flow direction of the sealing medium will gradually be guided to the first sharp corner of the dynamic pressure groove; the V-shaped groove structure design of the dynamic pressure groove can produce a greater fluid dynamic pressure effect than the ordinary spiral groove, so that the seal has a strong liquid film stiffness at high speeds, thereby improving the stability of the seal. When the sealing medium enters the upstream pumping groove, the groove area of the upstream pumping groove passed by the sealing medium changes from wide to narrow. The upstream pumping effect generated by the V-shaped groove structure design of the upstream pumping groove is stronger than that of the ordinary groove shape, which can effectively reduce the leakage of the seal under high speed conditions.

[0010] The sealing device of the embodiment of the present invention can effectively reduce the friction, wear and leakage of the sealing end face within the entire speed range. It is not only applicable to nuclear main pumps, but also improves the performance of nuclear main pumps, which is of great significance to ensuring the safe and efficient operation of nuclear power plants. It is also applicable to other industries such as petroleum, chemical industry, electric power, etc., and provides strong technical support for the design of sealing groove structures of various rotating equipment.

[0011] In some embodiments, the depth of the dynamic pressure groove and the upstream pumping groove is 3-40 microns.

[0012] In some embodiments, both the first sidewall surface and the second sidewall surface are V-shaped surfaces.

[0013] In some embodiments, the first side wall surface is located on the convex side of the dynamic pressure groove, the second side wall surface is located on the concave side of the dynamic pressure groove, and the V-shaped angle of the first side wall surface is smaller than the V-shaped angle of the second side wall surface.

[0014] In some embodiments, the V-shaped angle of the first sidewall surface is 40-50 degrees, and the V-shaped angle of the second sidewall surface is 80-100 degrees.

[0015] In some embodiments, the first sidewall surface and the second sidewall surface are both curved surfaces.

[0016] In some embodiments, the dynamic pressure groove and the upstream pumping groove are both stepped grooves.

[0017] In some embodiments, the sealing end surface includes a ground conical surface, and the dynamic pressure grooves are distributed on the ground conical surface.

[0018] In some embodiments, the taper of the ground conical surface is less than 0.9 microns.

[0019] In some embodiments, the radial inner end of the dynamic pressure groove is located near the ring center line of the sealing end surface; the radial inner end of the upstream pumping groove is located near the ring center line of the sealing end surface.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram of the sealing end face of a sealing ring in the mechanical sealing device of the present invention;

[0023] Figure 2It is a partial longitudinal cross-sectional schematic diagram of another sealing ring in the mechanical sealing device of the present invention;

[0024] Figure 3 This is a schematic diagram of the sealing end face of another sealing ring in the mechanical sealing device of the present invention;

[0025] Figure 4 This is a schematic diagram of the sealing end face of another sealing ring in the mechanical sealing device of the present invention;

[0026] Figure 5 This is a schematic diagram of the sealing end face of another sealing ring in the mechanical sealing device of the present invention.

[0027] Reference numerals:

[0028] Sealing ring 1; dynamic pressure groove 11; first side wall surface 111; V-shaped angle a of first side wall surface 111; second side wall surface 112; V-shaped angle b of second side wall surface 112; first sharp angle 113; shallow dynamic pressure groove 114; deep dynamic pressure groove 115; upstream pumping groove 12; third side wall surface 121; fourth side wall surface 122; second sharp angle 123; shallow upstream pumping groove 124; deep upstream pumping groove 125; ground conical surface 13; taper h T ; Ring center line 14. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0030] The following combination Figures 1 to 5 The mechanical sealing device of the embodiment of the present invention is described below.

[0031] like Figure 1 、 Figures 3 to 5 As shown, the mechanical sealing device according to the embodiment of the present invention includes a sealing ring 1, and a sealing end surface of the sealing ring 1 is provided with a plurality of V-shaped dynamic pressure grooves 11 and a plurality of V-shaped upstream pumping grooves 12.

[0032] Specifically, a plurality of dynamic pressure grooves 11 are distributed at intervals along the circumference of the sealing ring 1 on the outer side of the sealing end surface, and the directions of the plurality of dynamic pressure grooves 11 are consistent along the circumference of the sealing ring 1, for example, Figure 1 、 Figures 3 to 5It is shown that the middle convex portion of the dynamic pressure groove 11 is arranged in the counterclockwise direction; each dynamic pressure groove 11 includes a first side wall surface 111 and a second side wall surface 112 that are opposite to each other in the circumferential direction of the sealing ring 1, and the radial outer ends of the first side wall surface 111 and the second side wall surface 112 are located on the outer peripheral surface of the sealing ring 1 and there is a distance between the radial outer ends of the first side wall surface 111 and the second side wall surface 112, so that the dynamic pressure groove 11 has an inlet on the peripheral surface of the sealing ring 1 for the sealing medium to flow into the dynamic pressure groove 11, and the width between the first side wall surface 111 and the second side wall surface 112 gradually increases from the outside to the inside in the radial direction of the sealing end surface and then gradually decreases until the radial inner ends of the first side wall surface 111 and the second side wall surface 112 intersect to form a first sharp angle 113. Figure 1 、 Figures 3 to 5 The diagram shows that when the central convex portion of the dynamic pressure groove 11 is arranged counterclockwise, the sealing ring 1 rotates clockwise during operation. When the sealing ring 1 rotates at a high speed, as the sealing medium flows from the outer diameter to the inner diameter of the sealing ring 1, it first passes through the dynamic pressure groove 11. The groove area of the dynamic pressure groove 11 gradually widens and then narrows, and the sealing medium flow is gradually guided to the first sharp corner 113 of the dynamic pressure groove 11. The V-shaped structure of the dynamic pressure groove 11 produces a greater fluid dynamic pressure effect than a conventional spiral groove, which gives the seal a strong liquid film stiffness at high speeds and improves the stability of the seal.

[0033] The plurality of upstream pumping grooves 12 are distributed at intervals along the circumference of the sealing ring 1 on the inner side of the sealing end surface and correspond to the plurality of dynamic pressure grooves 11 in the radial direction. The directions of the plurality of upstream pumping grooves 12 are consistent in the circumferential direction of the sealing ring 1 and are opposite to the directions of the plurality of dynamic pressure grooves 11. For example, Figure 1 、 Figures 3 to 5 It is shown that the middle convex portion of the upstream pumping groove 12 is arranged in a clockwise direction; each upstream pumping groove 12 includes a third side wall surface 121 and a fourth side wall surface 122 that are opposite to each other in the circumferential direction of the sealing ring 1, and the radial inner ends of the third side wall surface 121 and the fourth side wall surface 122 are located on the inner circumferential surface of the sealing ring 1 and there is a distance between the radial inner ends of the third side wall surface 121 and the fourth side wall surface 122, so that the upstream pumping groove 12 has an outlet on the inner circumferential surface of the sealing ring 1 for the sealing medium to flow out of the upstream pumping groove 12, and the width between the third side wall surface 121 and the fourth side wall surface 122 gradually increases from the inside to the outside in the radial direction of the sealing end face and then gradually decreases until the radial outer ends of the third side wall surface 121 and the fourth side wall surface 122 intersect to form a second sharp angle 123. Figure 1 、 Figures 3 to 5The diagram shows that when the central convex portion of the dynamic pressure groove 11 is arranged counterclockwise, the sealing ring 1 rotates clockwise during operation. When the sealing medium enters the upstream pumping groove 12, the groove area of the upstream pumping groove 12 through which the sealing medium passes narrows from wide. The V-shaped structure of the upstream pumping groove 12 produces a stronger upstream pumping effect than ordinary grooves, effectively reducing seal leakage under high speed conditions.

[0034] According to the mechanical sealing device of the embodiment of the present invention, when the sealing ring 1 is in operation, the rotation direction of the sealing ring 1 is opposite to the direction of the dynamic pressure groove 11; when the speed of the sealing ring 1 is very low, the fluid static pressure effect formed on the sealing end face will cause the sealing end face to open, reducing the friction and wear under low speed conditions; when the speed of the sealing ring 1 is relatively high, in the process of the sealing medium flowing from the outer diameter to the inner diameter of the sealing ring 1, the sealing medium first passes through the dynamic pressure groove 11, and the groove area of the dynamic pressure groove 11 passed through changes from narrow to wide and then from wide to narrow, and the flow direction of the sealing medium will gradually be guided to the first sharp corner 113 of the dynamic pressure groove 11; the V-shaped groove structure design of the dynamic pressure groove 11 can produce a greater fluid dynamic pressure effect than the ordinary spiral groove, so that the seal has a strong liquid film stiffness at high speed, thereby improving the stability of the seal. When the sealing medium enters the upstream pumping groove 12, the groove area of the upstream pumping groove 12 through which the sealing medium passes becomes narrower. The upstream pumping effect produced by the V-shaped groove structure design of the upstream pumping groove 12 is stronger than that of the ordinary groove shape, and can effectively reduce the leakage of the seal under high speed conditions.

[0035] The sealing device of the embodiment of the present utility model can enhance the end face fluid dynamic pressure effect, enhance the anti-interference ability of the seal, and reduce the friction, wear and leakage of the sealing end face within the entire speed range. It is not only suitable for nuclear main pumps, but also improves the performance of nuclear main pumps, which is of great significance to ensuring the safe and efficient operation of nuclear power plants. It is also suitable for other industries such as petroleum, chemical industry, and electric power, and provides strong technical support for the design of sealing groove structures of various rotating equipment.

[0036] In some embodiments, the depth of the dynamic pressure groove 11 and the upstream pumping groove 12 is 3-40 microns. For example, the depth of the dynamic pressure groove 11 can be 3 microns, 10 microns, 20 microns, 30 microns and 40 microns, which can be appropriately adjusted within the range of 3-40 microns according to actual needs. Similarly, the depth of the upstream pumping groove 12 can be 3 microns, 10 microns, 20 microns, 30 microns and 40 microns, which can be appropriately adjusted within the range of 3-40 microns according to actual needs. The dynamic pressure groove 11 in this depth range can make the seal easier to open and can produce a greater fluid dynamic pressure effect, so that the seal has a strong liquid film stiffness at high speed, thereby improving the stability of the seal. The upstream pumping groove 12 in this depth range has a better pumping effect and can effectively reduce the leakage of the seal under high speed conditions.

[0037] In some embodiments, as Figure 1 and Figure 3 As shown, the first side wall surface 111 and the second side wall surface 112 are both V-shaped surfaces, so that a similar V-shaped dynamic pressure groove 11 can be formed between the first side wall surface 111 and the second side surface. When the rotation speed of the sealing ring 1 is high, in the process of the sealing medium flowing from the outer diameter to the inner diameter of the sealing ring 1, the sealing medium first passes through the dynamic pressure groove 11. The groove area of the dynamic pressure groove 11 passed through changes from narrow to wide and then from wide to narrow. The flow direction of the sealing medium will gradually be guided to the first sharp corner 113 of the dynamic pressure groove 11; the V-shaped groove structure design of the dynamic pressure groove 11 can produce a greater fluid dynamic pressure effect than the ordinary spiral groove, so that the seal has a strong liquid film stiffness at high rotation speeds, thereby improving the stability of the seal.

[0038] In some embodiments, as Figure 1 As shown, the first side wall surface 111 is located on the convex side of the dynamic pressure groove 11, and the second side wall surface 112 is located on the concave side of the dynamic pressure groove 11. The V-shaped angle a of the first side wall surface 111 is smaller than the V-shaped angle b of the second side wall surface 112. When the rotational speed of the sealing ring 1 is high, as the sealing medium flows from the outer diameter to the inner diameter of the sealing ring 1, the sealing medium first passes through the dynamic pressure groove 11. The groove area of the dynamic pressure groove 11 passed through changes from narrow to wide and then from wide to narrow, and the flow of the sealing medium is gradually guided to the first sharp corner 113 of the dynamic pressure groove 11. The V-shaped groove structure design of the dynamic pressure groove 11 can produce a greater fluid dynamic pressure effect than an ordinary spiral groove, which makes the seal have a strong liquid film stiffness at high rotational speeds and improves the stability of the seal.

[0039] In some embodiments, the V-shaped angle a of the first sidewall surface 111 is 40-50 degrees, for example, 45 degrees; the V-shaped angle b of the second sidewall surface 112 is 80-100 degrees, for example, 90 degrees. The dynamic pressure groove 11 generates a greater fluid dynamic pressure effect, which gives the seal strong liquid film stiffness at high rotational speeds, thereby improving the stability of the seal.

[0040] In some embodiments, as Figure 5 As shown, the first side wall surface 111 and the second side wall surface 112 are both curved surfaces. The curve types of the curved surface include but are not limited to logarithmic curves, polynomial curves, and elliptical curves. When the rotation speed of the sealing ring 1 is high, in the process of the sealing medium flowing from the outer diameter to the inner diameter of the sealing ring 1, the sealing medium first passes through the dynamic pressure groove 11. The groove area of the dynamic pressure groove 11 passed through changes from narrow to wide and then from wide to narrow. The flow direction of the sealing medium will gradually be guided to the first sharp corner 113 of the dynamic pressure groove 11; the V-shaped groove structure design of the dynamic pressure groove 11 can produce a greater fluid dynamic pressure effect than the ordinary spiral groove, so that the seal has a strong liquid film stiffness at high rotation speed, thereby improving the stability of the seal.

[0041] In some embodiments, as Figure 4 As shown, the dynamic pressure groove 11 and the upstream pumping groove 12 are both stepped grooves. Specifically, each dynamic pressure groove 11 can be composed of a dynamic pressure shallow groove 114 and a dynamic pressure deep groove 115, the dynamic pressure deep groove 115 is located on the inner side of the dynamic pressure shallow groove 114, the depth of the dynamic pressure shallow groove 114 is between 3-20 microns, the depth of the dynamic pressure deep groove 115 is between 20-40 microns, and the specific depths and sizes of the dynamic pressure shallow groove 114 and the dynamic pressure deep groove 115 can be adjusted according to actual conditions; each upstream pumping groove 12 can be composed of an upstream pumping shallow groove 124 and an upstream pumping deep groove 125, the upstream pumping deep groove 125 is located on the inner side of the upstream pumping shallow groove 124, the depth of the upstream pumping shallow groove 124 is between 3-20 microns, the depth of the upstream pumping deep groove 125 is between 20-40 microns, and the specific depths and sizes of the upstream pumping shallow groove 124 and the upstream pumping deep groove 125 can be adjusted according to actual conditions. As a result, such a structure can produce a stronger fluid dynamic pressure effect and upstream pumping effect.

[0042] In some implementations, such as Figure 2 As shown, the sealing end surface includes a ground conical surface 13, and the dynamic pressure grooves 11 are distributed on the ground conical surface 13. When the speed of the sealing ring 1 is very low or no speed, the taper h of the ground conical surface 13 is T It will form a better hydrostatic effect, making it easier to open the sealing end face, effectively reducing the end face friction wear under low speed or no speed conditions, that is, reducing the end face wear of the sealing ring 1 when it starts running.

[0043] In some embodiments, the taper h of the ground conical surface 13 is T Less than 0.9 microns. When the speed of the sealing ring 1 is very low or no speed, the taper h of the grinding cone surface 13 is less than 0.9 microns. T A better hydrostatic effect will be formed, making it easier for the sealing end face to open, effectively reducing the end face friction wear under low speed or no speed conditions, that is, reducing the end face wear of the sealing ring 1 when starting to run.

[0044] In some embodiments, as Figure 1 and Figure 3 As shown, the radial inner end of the dynamic pressure groove 11 is located near the ring center line 14 of the sealing end surface, and the radial inner end of the upstream pumping groove 12 is located near the ring center line 14 of the sealing end surface. Figure 1 As shown, the radial inner end of the dynamic pressure groove 11 is located outside the ring center line 14, and the upstream pumping groove 12 is located inside the ring center line 14. The distance between the dynamic pressure groove 11 and the upstream pumping groove 12 is relatively far, and the dynamic pressure groove 11 and the upstream pumping groove 12 are separated by the ring center line 14 and do not interfere with each other; Figure 2As shown, the radial inner end of the dynamic pressure groove 11 is located within the ring center line 14, and the radial outer end of the upstream pumping groove 12 is located outside the annular center line. The dynamic pressure groove 11 and the upstream pumping groove 12 are close to each other and are staggered at the ring center line 14, which can produce a stronger fluid dynamic pressure effect and upstream pumping effect.

[0045] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0046] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A mechanical sealing device, characterized in that: The sealing ring comprises a sealing ring, wherein a sealing end surface of the sealing ring is provided with a plurality of V-shaped dynamic pressure grooves and a plurality of V-shaped upstream pumping grooves; wherein a plurality of the dynamic pressure grooves are distributed at intervals along the circumferential direction of the sealing ring on the outer side of the sealing end surface, and the directions of the plurality of dynamic pressure grooves are consistent in the circumferential direction of the sealing ring; each of the dynamic pressure grooves comprises a first side wall surface and a second side wall surface that are opposite to each other in the circumferential direction of the sealing ring, wherein the radial outer ends of the first side wall surface and the second side wall surface are located on the outer circumferential surface of the sealing ring, and there is a distance between the radial outer ends of the first side wall surface and the second side wall surface, and the width between the first side wall surface and the second side wall surface gradually increases from the outside to the inside in the radial direction of the sealing end surface and then gradually decreases until the radial inner ends of the first side wall surface and the second side wall surface intersect to form a first sharp angle; The plurality of upstream pumping grooves are distributed at intervals along the circumference of the sealing ring on the inner side of the sealing end face and correspond to the plurality of dynamic pressure grooves in the radial direction. The directions of the plurality of upstream pumping grooves are consistent in the circumferential direction of the sealing ring and are opposite to the directions of the plurality of dynamic pressure grooves. Each of the upstream pumping grooves includes a third side wall surface and a fourth side wall surface that are opposite to each other in the circumferential direction of the sealing ring. The radial inner ends of the third side wall surface and the fourth side wall surface are located on the inner circumferential surface of the sealing ring and there is a spacing between the radial inner ends of the third side wall surface and the fourth side wall surface. The width between the third side wall surface and the fourth side wall surface gradually increases from the inside to the outside in the radial direction of the sealing end face and then gradually decreases until the radial outer ends of the third side wall surface and the fourth side wall surface intersect to form a second sharp angle.

2. The mechanical sealing device according to claim 1, characterized in that: The depths of the dynamic pressure groove and the upstream pumping groove are 3-40 microns.

3. The mechanical sealing device according to claim 1, characterized in that: The first side wall surface and the second side wall surface are both V-shaped surfaces.

4. The mechanical sealing device according to claim 3, characterized in that: The first side wall surface is located on the convex side of the dynamic pressure groove, the second side wall surface is located on the concave side of the dynamic pressure groove, and a V-shaped angle of the first side wall surface is smaller than a V-shaped angle of the second side wall surface.

5. The mechanical sealing device according to claim 4, characterized in that: The V-shaped angle of the first side wall is 40-50 degrees, and the V-shaped angle of the second side wall is 80-100 degrees.

6. The mechanical sealing device according to claim 1, characterized in that: The first side wall surface and the second side wall surface are both curved surfaces.

7. The mechanical sealing device according to claim 1, characterized in that: The dynamic pressure groove and the upstream pumping groove are both stepped grooves.

8. The mechanical sealing device according to claim 1, characterized in that: The sealing end surface includes a ground conical surface, and the dynamic pressure grooves are distributed on the ground conical surface.

9. The mechanical sealing device according to claim 8, characterized in that: The taper of the grinding cone surface is less than 0.9 microns.

10. The mechanical sealing device according to claim 1, characterized in that: The radial inner end of the dynamic pressure groove is located near the ring center line of the sealing end surface; the radial inner end of the upstream pumping groove is located near the ring center line of the sealing end surface.

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