A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium

Abstract

The present application relates to a mechanical seal structure for a nuclear main pump with a controllable leakage of oil medium and a large shaft diameter, which includes a dynamic ring assembly, a cover assembly, and a static ring assembly. The dynamic ring assembly includes a shaft sleeve and a sealing dynamic ring. The cover assembly includes an insertion ring disposed in the housing. The static ring assembly includes a static ring seat and a sealing static ring. The static ring seat is circumferentially disposed on the insertion ring, and the sealing static ring is circumferentially disposed on the static ring seat and is used to abut against the sealing dynamic ring. A first collection space that communicates with each other is left between the sealing dynamic ring and the shaft sleeve, between the sealing static ring and the shaft sleeve, and between the static ring seat and the shaft sleeve. The first collection space is used to collect the high-viscosity oil medium leaking along between the sealing dynamic ring and the sealing static ring. A collection mechanism for collecting the high-viscosity oil medium rising in the first collection space when the shaft sleeve rotates is provided on the insertion ring. The present application has the advantage of timely treating the leaked high-viscosity oil medium, thereby preventing the high-viscosity oil medium from affecting the seal structure.

Description

Technical Field

[0001] The present application relates to the field of mechanical seals, and in particular to a mechanical seal structure for a nuclear primary pump with a controllable leakage of oil medium and a large shaft diameter. Background Art

[0002] With the development of petroleum, petrochemical equipment, and nuclear power equipment, more and more reactor equipment and fourth-generation nuclear primary pump equipment are put into use. These reactor equipment and fourth-generation nuclear primary pump equipment have the characteristics of super-large shaft diameter, high linear velocity, ultra-high temperature, and high-viscosity oil medium inside. The existing traditional mechanical seal structure includes a dynamic ring sleeved and fixedly connected to the main shaft and a static ring fixedly arranged in the shell and used to abut against the dynamic ring. When the main shaft drives the dynamic ring to rotate, the dynamic ring can rotate on the static ring, so that the dynamic ring and the static ring achieve effective sealing. However, when partial leakage occurs at the sealing end face between the dynamic ring and the static ring with high-viscosity oil medium, if the leaked high-viscosity oil medium is not treated in time, it will affect the sealing effect of the entire mechanical seal structure. Summary of the Invention

[0003] In order to timely treat the leaked high-viscosity oil medium and prevent the high-viscosity oil medium from affecting the sealing structure, the present application provides a mechanical seal structure for a nuclear primary pump with a controllable leakage of oil medium and a large shaft diameter.

[0004] A mechanical seal structure for a nuclear primary pump with a controllable leakage of oil medium and a large shaft diameter provided by the present application adopts the following technical solutions:

[0005] A mechanical seal structure for a nuclear primary pump with a controllable leakage of oil medium and a large shaft diameter includes a dynamic ring assembly, a cover body assembly, and a static ring assembly. The dynamic ring assembly includes a shaft sleeve and a sealing dynamic ring. The shaft sleeve is sleeved and fixedly connected to the main shaft. The sealing dynamic ring is circumferentially arranged on the shaft sleeve. The cover body assembly includes an insertion ring arranged in the shell. The insertion ring is circumferentially arranged along the shaft sleeve. The static ring assembly includes a static ring seat and a sealing static ring. The static ring seat is circumferentially arranged on the insertion ring. The sealing static ring is circumferentially arranged on the static ring seat and used to abut against the sealing dynamic ring. A first collection space that communicates with each other is left between the sealing dynamic ring and the shaft sleeve, between the sealing static ring and the shaft sleeve, and between the static ring seat and the shaft sleeve. The first collection space is used to collect the high-viscosity oil medium leaking along between the sealing dynamic ring and the sealing static ring. A collection mechanism for collecting the high-viscosity oil medium rising in the first collection space when the shaft sleeve rotates is arranged on the insertion ring.

[0006] By adopting the above technical solution, when the main shaft drives the sleeve to rotate, the sleeve can drive the dynamic sealing ring to rotate on the static sealing ring, so that the dynamic sealing ring and the static sealing ring achieve sealing. When the highly viscous oil medium being processed leaks between the dynamic sealing ring and the static sealing ring, the leaked highly viscous oil medium can flow into the first collection space between the dynamic sealing ring and the sleeve and between the static sealing ring and the sleeve. At this time, the main shaft drives the sleeve to rotate, which has an extrusion effect on the highly viscous oil medium in the first collection space, causing the highly viscous oil medium to rise along the first collection space to the first collection space between the static ring seat and the sleeve. The highly viscous oil medium continuously rises to the position where the collection mechanism is located, enabling the collection mechanism to process the leaked highly viscous oil medium, facilitating the automatic processing of the highly viscous oil medium during the operation of the entire device, and preventing the leaked part of the highly viscous oil medium from affecting the sealing structure.

[0007] Optionally, a second collection space for the highly viscous oil medium in the first collection space to move into is left between the insertion ring and the sleeve. A collection groove is circumferentially formed on the inner wall of the insertion ring. An oil-slinging structure is provided on the outer wall of the sleeve for slinging the highly viscous oil medium rising in the second collection space into the collection groove when rotating. The collection mechanism is used to collect the highly viscous oil medium collected in the collection groove.

[0008] By adopting the above technical solution, when the highly viscous oil medium rises to the position where the collection groove is located, the main shaft drives the sleeve to rotate. At this time, the highly viscous oil medium is slung into the collection groove by the oil-slinging mechanism, facilitating the collection mechanism to process the highly viscous oil medium collected in the collection groove and further improving the collection effect of the highly viscous oil medium.

[0009] Optionally, a protrusion is provided on the bottom wall of the collection groove and near the sleeve. A collection cavity is formed between the protrusion and the collection groove to prevent the highly viscous oil medium in the collection groove from flowing back into the second collection space.

[0010] By adopting the above technical solution, the highly viscous oil medium slung into the collection groove by the oil-slinging structure can be blocked by the protrusion, preventing the highly viscous oil medium in the collection groove from flowing out of the collection groove and improving the collection effect of the collection groove on the highly viscous oil medium.

[0011] Optionally, the top wall of the collection groove is arranged as an inclined surface extending in a direction away from the collection groove.

[0012] By adopting the above technical solution, the highly viscous oil medium flowing down on the outer wall of the insertion ring can flow into the collection groove along the inclined surface, further improving the collection effect of the collection groove on the highly viscous oil medium.

[0013] Optionally, a groove is provided on the bushing at a position relative to the collection groove, and the oil slinging structure includes convex rings arranged at intervals along the axial direction of the bushing in the groove.

[0014] By adopting the above technical solution, when the high-viscosity oil medium rises to the position where the convex ring is located, due to the rotation of the bushing driving the convex ring, the high-viscosity oil medium is slung into the collection groove by centrifugal force, thereby realizing the collection of the high-viscosity oil medium. The structure of the convex ring is simple, and the high rotation speed of the bushing is used to realize the collection of the high-viscosity oil medium, improving the collection effect of moving the high-viscosity oil medium into the collection groove.

[0015] Optionally, the bottom wall of the convex ring is arranged horizontally, the top wall of the convex ring is inclined, and the distance between the top wall and the bottom wall of the convex ring gradually increases towards the direction close to the bushing.

[0016] By adopting the above technical solution, when the high-viscosity oil medium moves to the position where the bottom wall of the convex ring is located, the horizontally arranged bottom wall of the convex ring can block the high-viscosity oil medium, so that the high-viscosity oil medium is slung into the collection groove along the horizontally arranged bottom wall of the convex ring, improving the slinging effect on the high-viscosity oil medium. And the top wall of the convex ring is inclined, and the high-viscosity oil medium moving above the convex ring flows down along the inclined top wall of the convex ring, and then moves to the end of the convex ring far from the bushing and is slung into the collection groove, further improving the slinging effect of the convex ring on the high-viscosity oil medium.

[0017] Optionally, the cover assembly includes a gland arranged in the housing, the gland is arranged circumferentially along the bushing, the insertion ring is arranged circumferentially on the gland, the collection mechanism includes a first collection hole opened on the gland and a second collection hole opened on the insertion ring, the second collection hole is communicated with the collection groove, the first collection hole is communicated with the second collection hole, and the end of the first collection hole far from the second collection hole penetrates through the gland.

[0018] By adopting the above technical solution, the operator can process and collect the high-viscosity oil medium outside the gland through the first collection hole and the second collection hole, with a simple structure and improved processing effect on the high-viscosity oil medium.

[0019] Optionally, the static sealing ring is slidably arranged axially on the insertion ring, and a contact member for driving the static sealing ring on the static ring seat to always have a tendency to move towards the dynamic sealing ring is arranged on the gland.

[0020] By adopting the above technical solution, the contact member can drive the static sealing ring to always abut against the dynamic sealing ring, thereby improving the sealing effect between the static sealing ring and the dynamic sealing ring and preventing excessive leakage from causing excessive collection pressure of the collection mechanism.

[0021] Optionally, the abutting member includes a plurality of springs disposed between the gland and the stationary ring seat, and the springs are used to drive the sealing stationary ring on the stationary ring seat to always abut against the sealing moving ring.

[0022] By adopting the above technical solution, when the spring is in a compressed state, the sealing stationary ring can abut against the sealing moving ring by the elastic force of the spring, thereby improving the abutting effect between the sealing stationary ring and the sealing moving ring.

[0023] Optionally, a seal is provided on the stationary ring seat for sealing the gap between the stationary ring seat and the insertion ring when the stationary ring seat slides on the insertion ring.

[0024] By adopting the above technical solution, the seal can seal the gap between the stationary ring seat and the insertion ring, preventing the high-viscosity oil medium leaking along the gap between the sealing stationary ring and the sealing moving ring from leaking along the gap between the stationary ring seat and the insert, and improving the sealing effect between the stationary ring seat and the insertion ring.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. When the main shaft drives the sleeve to rotate, the sleeve can drive the sealing moving ring to rotate on the sealing stationary ring, so that the sealing moving ring and the sealing stationary ring are sealed. When the processed high-viscosity oil medium leaks between the sealing moving ring and the sealing stationary ring, the leaked high-viscosity oil medium can flow into the first collection space between the sealing moving ring and the sleeve and between the sealing stationary ring and the sleeve. At this time, the main shaft drives the sleeve to rotate, squeezing the high-viscosity oil medium in the first collection space, so that the high-viscosity oil medium rises along the first collection space to the first collection space between the stationary ring seat and the sleeve. The high-viscosity oil medium continuously rises to the position where the collection mechanism is located, so that the collection mechanism can process the leaked high-viscosity oil medium, facilitating the automatic processing of the high-viscosity oil medium during the operation of the entire equipment and preventing the leaked part of the high-viscosity oil medium from affecting the sealing structure;

[0027] 2. When the high-viscosity oil medium rises to the position where the collection tank is located, the main shaft drives the sleeve to rotate. At this time, the high-viscosity oil medium is thrown into the collection tank by the oil throwing mechanism, so that the collection mechanism can easily process the high-viscosity oil medium collected in the collection tank, further improving the collection effect of the high-viscosity oil medium.

[0028] 3. When the high-viscosity oil medium moves to the position where the bottom wall of the convex ring is located, the horizontally arranged bottom wall of the convex ring can block the high-viscosity oil medium, so that the high-viscosity oil medium is thrown along the bottom wall of the horizontally arranged convex ring into the collection tank, improving the throwing effect on the high-viscosity oil medium. The top wall of the convex ring is arranged obliquely, and the high-viscosity oil medium moving above the convex ring flows down along the inclined top wall of the convex ring, and then moves to the end of the convex ring away from the shaft sleeve and is thrown into the collection tank, further improving the throwing effect of the convex ring on the high-viscosity oil medium. Brief Description of the Drawings

[0029] Figure 1 is the overall structural schematic diagram of the embodiment of the present application;

[0030] Figure 2 is the partial structural schematic diagram of the embodiment of the present application;

[0031] Figure 3 is the structural schematic diagram of the hydrodynamic groove for demonstrating the embodiment of the present application;

[0032] Figure 4 is Figure 2 the enlarged view of part A in

[0033] Description of the Reference Numerals: 1, shaft sleeve; 11, dynamic seal ring; 111, O-ring; 112, flanging; 113, first sealing ring; 114, dynamic ring seat; 115, limiting ring; 116, limiting groove; 12, gland; 121, insertion ring; 122, limiting groove; 123, second sealing ring; 124, third sealing ring; 125, positioning plate; 126, positioning groove; 13, static ring seat; 131, static seal ring; 132, mounting seat; 133, mounting groove; 134, fourth sealing ring; 135, sliding groove; 136, fifth sealing ring; 137, mounting ring; 14, spring; 141, groove body; 15, hydrodynamic groove; 16, first collection space; 161, second collection space; 17, collection tank; 171, protrusion; 172, collection cavity; 173, inclined surface; 174, groove; 175, convex ring; 18, first collection hole; 181, second collection hole. Detailed Description of the Embodiment

[0034] The following Figures 1-4 further describes the present application in detail with reference to the attached drawings.

[0035] The embodiment of the present application discloses a mechanical seal structure of a nuclear main pump with a controllable leakage oil medium and a large shaft diameter. Referring to Figure 1 , a mechanical seal structure of a nuclear main pump with a controllable leakage oil medium and a large shaft diameter includes a dynamic ring assembly, a cover body assembly and a static ring assembly.

[0036] Combined with Figure 1 andFigure 2 The moving ring assembly includes a shaft sleeve 1 and a sealing moving ring 11. The shaft sleeve 1 is sleeved and fixedly connected to the main shaft. The sealing moving ring 11 is circumferentially arranged on the shaft sleeve 1. In this embodiment, O-rings 111 for abutting against the main shaft are circumferentially clamped on the inner wall of the shaft sleeve 1 at both the upper and lower parts of the shaft sleeve 1. A flanging 112 is circumferentially arranged at the lower edge of the shaft sleeve 1. A first sealing ring 113 for abutting against the sealing moving ring 11 is circumferentially clamped on the surface of the flanging 112 facing the sealing moving ring 11. The first sealing ring 113 is used to seal the gap between the sealing moving ring 11 and the flanging 112. A moving ring seat 114 is detachably connected to the flanging 112 by bolts. A limiting ring 115 is circumferentially arranged on the inner wall of the moving ring seat 114. A limiting groove 116 for the limiting ring 115 to move into is circumferentially formed on the outer wall of the sealing moving ring 11. The sealing moving ring 11 is arranged on the shaft sleeve 1 through the moving ring seat 114 and the flanging 112.

[0037] Combined with Figure 1 and Figure 2 The cover body assembly includes a gland 12 arranged in the housing and an insertion ring 121 arranged in the housing. The gland 12 is circumferentially arranged along the shaft sleeve 1. The insertion ring 121 is circumferentially arranged along the shaft sleeve 1. In this embodiment, a limiting groove 122 is formed on the inner wall of the gland 12 at the edge far from the flanging 112. The cross-section of the insertion ring 121 is in an "L" shape. The horizontal section of the "L"-shaped insertion ring 121 is used to be inserted into the limiting groove 122. A second sealing ring 123 for abutting against the inner wall of the limiting groove 122 is circumferentially clamped on the horizontal section of the "L"-shaped insertion ring 121. The vertical section of the "L"-shaped insertion ring 121 is used to abut against the inner wall of the gland 12. A third sealing ring 124 for abutting against the vertical section of the "L"-shaped insertion ring 121 is circumferentially clamped on the inner wall of the gland 12. In order to position the insertion ring 121, a positioning plate 125 is detachably connected to the horizontal section of the "L"-shaped insertion ring 121 by bolts. A positioning groove 126 for the positioning plate 125 to move into is circumferentially formed on the outer wall of the shaft sleeve 1. The insertion ring 121 is arranged in the housing through the gland 12.

[0038] Combined with Figure 1 and Figure 2The stationary ring assembly includes a stationary ring seat 13 and a sealing stationary ring 131. The stationary ring seat 13 is circumferentially arranged on the insert ring 121. The sealing stationary ring 131 is circumferentially arranged on the stationary ring seat 13 and is used to abut against the sealing dynamic ring 11. In this embodiment, a mounting seat 132 is detachably connected to the stationary ring seat 13 by bolts. A mounting ring 137 is circumferentially arranged on the inner wall of the mounting seat 132 and located at a position of the mounting seat 132 close to the dynamic ring seat 114. The outer wall of the sealing stationary ring 131 and located close to the sealing The sealing dynamic ring 11 is provided with an installation groove 133 in an annular direction for the installation ring 137 to move into. The installation ring 137 can restrict the sealing static ring 131 on the static ring seat 13. The sealing static ring 131 is arranged on the static ring seat 13 through the installation seat 132. The static ring seat 13 has a fourth sealing ring 134 in an annular direction and embedded on the surface facing the sealing dynamic ring 11 for abutting against the sealing dynamic ring 11, thereby preventing the leakage of high-viscosity oil media along the gap between the static ring seat 13 and the sealing static ring 131.

[0039] Combination Figure 1 and Figure 2 In order to drive the sealing static ring 131 to always abut against the sealing dynamic ring 11, the sealing static ring 131 is axially slidably arranged on the insert ring 121. In this embodiment, a sliding groove 135 is circumferentially opened on the inner wall of the static ring seat 13 for the vertical section of the "L"-shaped insert ring 121 to move into. The surface of the sliding groove 135 away from the sealing static ring 131 penetrates the static ring seat 13, and the surface of the sliding groove 135 close to the sealing static ring 131 is closed.

[0040] Combination Figure 1 and Figure 2 In order to seal the gap between the stationary ring seat 13 and the insert ring 121, a seal is provided on the stationary ring seat 13 for sealing the gap between the stationary ring seat 13 and the insert ring 121 when the stationary ring seat 13 slides on the insert ring 121; in the present embodiment, the seal includes a fifth sealing ring 136 which is circumferential and embedded in the surface of the sliding groove 135 facing the shaft sleeve 1, and the fifth sealing ring 136 is used to abut against the vertical section of the "L"-shaped insert ring 121, thereby sealing the gap between the stationary ring seat 13 and the insert ring 121.

[0041] Combination Figure 1 and Figure 2 The pressure cover 12 is provided with an abutment member for driving the sealing static ring 131 on the static ring seat 13 to always have a tendency to move toward the sealing dynamic ring 11; the abutment member includes a plurality of springs 14 arranged between the pressure cover 12 and the static ring seat 13, and the spring 14 is used to drive the sealing static ring 131 on the static ring seat 13 to always abut against the sealing dynamic ring 11. In this embodiment, a groove body 141 is provided on the surface of the pressure cover 12 facing the static ring seat 13 and at the position where each spring 14 is located, and one end of the spring 14 is fixedly connected to the bottom wall of the groove body 141, and the other end is fixedly connected to the static ring seat 13.

[0042] Combined with Figure 2 and Figure 3 In this embodiment, in order to reduce the leakage rate and drive the formation of an air film between the sealing dynamic ring 11 and the sealing static ring 131 to further improve the sealing effect, a plurality of hydrodynamic grooves 15 are circumferentially formed on the surface of the sealing dynamic ring 11 facing the sealing static ring 131. Each hydrodynamic groove 15 is linearly arranged on the sealing end face of the sealing dynamic ring 11. The length direction of the linear hydrodynamic groove 15 is perpendicular to the axis of the sealing dynamic ring 11. The depth of the hydrodynamic groove 15 is between 0.1 mm and 1 mm, thereby effectively controlling the leakage rate. Both the sealing dynamic ring 11 and the sealing static ring 131 are made of silicon carbide, and the hard-on-hard method is adopted to solve the blister problem of the sealing dynamic ring 11 and the sealing static ring 131.

[0043] As Figure 2 shown, a first collecting space 16 that communicates with each other is left between the sealing dynamic ring 11 and the sleeve 1, between the sealing static ring 131 and the sleeve 1, and between the static ring seat 13 and the sleeve 1. The first collecting space 16 is used to collect the high-viscosity oil medium leaking along between the sealing dynamic ring 11 and the sealing static ring 131. The first collecting space 16 is annularly arranged. A second collecting space 161 for the high-viscosity oil medium in the first collecting space 16 to move into is left between the insertion ring 121 and the sleeve 1. The second collecting space 161 is annularly arranged.

[0044] Combined with Figure 2 and Figure 4 On the inner wall of the insertion ring 121, a collecting groove 17 is circumferentially formed. A protrusion 171 is arranged on the bottom wall of the collecting groove 17 and close to the position of the sleeve 1. The cross section of the protrusion 171 is pointed. A collecting cavity 172 for preventing the high-viscosity oil medium in the collecting groove 17 from flowing back into the second collecting space 161 is formed between the protrusion 171 and the collecting groove 17. The top wall of the collecting groove 17 is set as an inclined surface 173 that extends obliquely in the direction away from the collecting groove 17.

[0045] Combined with Figure 2 and Figure 4 In order to fling the high-viscosity oil medium in the second collecting space 161 into the collecting groove 17, an oil flinging structure is arranged on the outer wall of the sleeve 1 for flinging the high-viscosity oil medium rising in the second collecting space 161 into the collecting groove 17 during rotation; a groove 174 is formed on the sleeve 1 and at a position relative to the collecting groove 17. The oil flinging structure includes a convex ring 175 that is arranged at intervals along the axial direction of the sleeve 1 in the groove 174; the bottom wall of the convex ring 175 is arranged horizontally, the top wall of the convex ring 175 is inclined, and the distance between the top wall and the bottom wall of the convex ring 175 gradually increases in the direction close to the sleeve 1.

[0046] Combined withFigure 2 and Figure 4 A collecting mechanism for collecting the highly viscous oil medium rising in the first collecting space 16 when the bushing 1 rotates is provided on the insertion ring 121. The collecting mechanism is used to collect the highly viscous oil medium collected in the collecting groove 17. The collecting mechanism includes a first collecting hole 18 opened on the gland 12 and a second collecting hole 181 opened on the insertion ring 121. Both the first collecting hole 18 and the second collecting hole 181 are arranged along the direction perpendicular to the axis of the bushing 1. The second collecting hole 181 communicates with the collecting groove 17, the first collecting hole 18 communicates with the second collecting hole 181, the end of the first collecting hole 18 far from the second collecting hole 181 penetrates through the gland 12, and the groove body 141 is arranged staggered with the first collecting hole 18 and the second collecting hole 181.

[0047] The implementation principle of the mechanical seal structure of the nuclear main pump with a controllable leakage oil medium and a large shaft diameter in the embodiment of the present application is as follows: When it is necessary to collect the highly viscous oil medium, the main shaft drives the bushing 1 to rotate, and the bushing 1 drives the sealing dynamic ring 11 to rotate on the sealing static ring 131. When the highly viscous oil medium leaks into the first collecting space 16, when the main shaft drives the bushing 1 to rotate, it can drive the highly viscous oil medium to rise into the second collecting space 161. When the highly viscous oil medium moves to the position where the convex ring 175 is located, it is thrown into the collecting groove 17 through the convex ring 175, so that the collecting groove 17 collects the highly viscous oil medium. At this time, the first collecting hole 18 and the second collecting hole 181 facilitate the treatment of the highly viscous oil medium, and facilitate the automatic treatment of the highly viscous oil medium during the operation of the entire device, preventing the leaked part of the highly viscous oil medium from affecting the sealing structure.

[0048] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A mechanical seal structure for a nuclear main pump with a large shaft diameter and an oil medium with controllable leakage, characterized in that: It includes a rotating ring assembly, a cover body assembly and a stationary ring assembly. The rotating ring assembly includes a sleeve (1) and a sealing rotating ring (11). The sleeve (1) is sleeved and fixedly connected to the main shaft. The sealing rotating ring (11) is circumferentially arranged on the sleeve (1). The cover body assembly includes an insertion ring (121) arranged in the shell. The insertion ring (121) is circumferentially arranged along the sleeve (1). The stationary ring assembly includes a stationary ring seat (13) and a sealing stationary ring (131). The stationary ring seat (13) is circumferentially arranged on the insertion ring (121). The sealing stationary ring (131) is circumferentially arranged on the stationary ring seat (13) and is used to abut against the sealing rotating ring (11). There is a first collection space (16) that is mutually connected between the sealing rotating ring (11) and the sleeve (1), between the sealing stationary ring (131) and the sleeve (1), and between the stationary ring seat (13) and the sleeve (1). The first collection space (16) is used to collect the high-viscosity oil medium leaking between the sealing rotating ring (11) and the sealing stationary ring (131). A collection mechanism is arranged on the insertion ring (121) for collecting the high-viscosity oil medium rising in the first collection space (16) when the sleeve (1) rotates; A second collection space (161) is left between the insertion ring (121) and the sleeve (1) for the high-viscosity oil medium in the first collection space (16) to move into. A collection groove (17) is circumferentially opened on the inner wall of the insertion ring (121). An oil-slinging structure is arranged on the outer wall of the sleeve (1) for slinging the high-viscosity oil medium rising in the second collection space (161) into the collection groove (17) when rotating. The collection mechanism is used to collect the high-viscosity oil medium collected in the collection groove (17); The cover body assembly includes a gland (12) arranged in the shell. The gland (12) is circumferentially arranged along the sleeve (1). The insertion ring (121) is circumferentially arranged on the gland (12). The collection mechanism includes a first collection hole (18) opened on the gland (12) and a second collection hole (181) opened on the insertion ring (121). The second collection hole (181) is communicated with the collection groove (17). The first collection hole (18) is communicated with the second collection hole (181). The end of the first collection hole (18) far from the second collection hole (181) penetrates through the gland (12); A protrusion (171) is arranged on the bottom wall of the collection groove (17) and is located close to the sleeve (1).

2. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium according to claim 1, characterized in that: A collection cavity (172) is formed between the protrusion (171) and the collection groove (17) for preventing the high-viscosity oil medium in the collection groove (17) from flowing back into the second collection space (161).

3. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium according to claim 1, characterized in that: The top wall of the collection groove (17) is set as an inclined surface (173) that extends obliquely in a direction away from the collection groove (17).

4. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium according to claim 1, characterized in that: A groove (174) is opened on the sleeve (1) at a position relative to the collection groove (17). The oil-slinging structure includes a convex ring (175) that is axially spaced in the groove (174) along the sleeve (1).

5. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium according to claim 4, characterized in that: The bottom wall of the convex ring (175) is arranged horizontally, the top wall of the convex ring (175) is inclined, and the distance between the top wall and the bottom wall of the convex ring (175) gradually increases in the direction close to the shaft sleeve (1).

6. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium, as claimed in claim 1, wherein: The stationary sealing ring (131) is slidably arranged axially on the insertion ring (121), and an abutting member for driving the stationary sealing ring (131) on the stationary ring seat (13) to always have a tendency to move towards the dynamic sealing ring (11) is arranged on the gland (12).

7. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium, as claimed in claim 6, wherein: The abutting member includes a plurality of springs (14) arranged between the gland (12) and the stationary ring seat (13), and the springs (14) are used to drive the stationary sealing ring (131) on the stationary ring seat (13) to always abut against the dynamic sealing ring (11).

8. A mechanical seal structure for a nuclear main pump with a large shaft diameter and a controllable leakage oil medium according to claim 6, characterized in that: A sealing member for sealing the gap between the stationary ring seat (13) and the insertion ring (121) when the stationary ring seat (13) slides on the insertion ring (121) is arranged on the stationary ring seat (13).

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