Mechanical sealing structure for nuclear power lead bismuth pump

Abstract

The mechanical sealing structure for the nuclear power lead bismuth pump comprises a shaft sleeve and a pump shaft, the shaft sleeve is sleeved with a shell, the two ends of the shell are provided with a connecting base and an annular pressing plate respectively, the shaft sleeve is connected with a movable ring assembly in a sealed mode, the connecting base is provided with a first static ring, and the annular pressing plate is provided with a second static ring. The first static ring and the second static ring are matched with the movable ring assembly to form a sealing surface; a parking sealing mechanism is mounted on the connecting seat, the parking sealing mechanism comprises a mounting seat, a top block and a base, a mounting cavity is formed in the mounting seat, the top block is slidably mounted in the mounting cavity, a first sealing ring is arranged on the top block, an inflation inlet communicated with the mounting cavity is formed in the base, and a limiting ring connected with the pump shaft is mounted in the mounting cavity; the ejector block drives the first sealing ring to extrude the limiting ring for sealing through self movement. The mechanical sealing structure has the beneficial effects that the mechanical sealing structure can be integrally replaced under the condition that a machine is not stopped, and sealing is conducted by inflating the inflating opening to drive the ejecting block to abut against the limiting ring.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of mechanical seals, in particular to a mechanical seal structure for a nuclear power lead-bismuth pump. BACKGROUND

[0002] The mechanical seal, also known as an end face seal, is a sealing structure applied to fluid equipment (such as a pump and a mixer), which mainly realizes dynamic sealing between a dynamic ring and a static ring through a high-speed rotating shaft body to avoid mutual communication between the inside and the outside of a sealing cavity. The nuclear power lead-bismuth pump is a special pump for circulating and conveying lead-bismuth alloy (a kind of liquid metal), and the lead-bismuth alloy has a high boiling point and can therefore operate in a high-temperature environment. However, the mechanical seal in the prior art mainly relies on a single static ring and a dynamic ring for sealing, and the sealing performance is insufficient in a high-temperature state.

[0003] At present, the maintenance of the nuclear power lead-bismuth pump is relatively complex, and when the mechanical seal structure leaks, the machine needs to be stopped for replacement, which not only affects the work efficiency but also may cause the air tightness of the pump body to be reduced during the replacement process. Therefore, a sealing structure capable of replacing the mechanical seal without stopping the machine is urgently needed. CONTENT OF THE INVENTION

[0004] One of the purposes of the application is to provide a mechanical seal structure for a nuclear power lead-bismuth pump which can solve at least one defect in the background art.

[0005] To achieve the above at least one purpose, the technical scheme adopted by the application is as follows: a mechanical seal structure for a nuclear power lead-bismuth pump, comprising a shaft sleeve and a pump shaft sleeved in the shaft sleeve, a shell being sleeved on the shaft sleeve, a connecting seat and an annular pressing plate being respectively installed at two ends of the shell, a dynamic ring assembly being sealingly connected to the shaft sleeve, a first static ring being installed on the connecting seat, a second static ring being installed on the annular pressing plate, and a sealing surface being formed by the first static ring, the second static ring and the dynamic ring assembly; a parking seal mechanism being installed on the connecting seat, the parking seal mechanism comprising a mounting seat, a top block and a base, an installation cavity being arranged in the mounting seat, the top block being slidingly installed in the installation cavity, and the base supporting the top block in cooperation with the mounting seat; a first sealing ring and a second sealing ring being arranged on the top block, the second sealing ring being sealed in cooperation with the inner wall of the base, an air inlet being arranged on the base and being communicated with the installation cavity, and a limiting ring being installed in the installation cavity and being connected with the pump shaft; the top block driving the first sealing ring to press and seal the limiting ring by moving itself.

[0006] Through the above arrangement, the dynamic ring assembly can cooperate with the first static ring and the second static ring to dynamically seal the two ends of the shaft sleeve, further improving the effect of mechanical sealing; the parking sealing mechanism can replace the mechanical sealing structure as a whole without stopping the machine; the installation cavity is inflated through the inflation port to drive the top block to move upward, at this time, the first sealing ring abuts against the limiting ring and seals the cavity, which not only improves the replacement speed of the mechanical seal, but also maintains the air tightness of the sealing cavity, ensuring that the operation of the nuclear lead-bismuth pump is not affected.

[0007] Preferably, the top block is provided with a reset mechanism for driving the top block to move. In this way, after the mechanical seal is replaced, the gas in the installation cavity can be discharged through the inflation port, and then the reset mechanism drives the top block to return to the initial position.

[0008] Preferably, the reset mechanism includes an elastic member, one end of the top block near the limiting ring is provided with a groove, one end of the elastic member is installed in the groove, and the other end abuts against the inner wall of the mounting seat. In this way, the elastic member can reset the top block, and when the top block moves towards the limiting ring, the elastic member is compressed and stores elasticity, and when the air pressure below the top block decreases, the elastic member drives the top block to reset through its own elastic force.

[0009] Preferably, the mounting seat is provided with a through hole in communication with the installation cavity, a limiting rod is slidably installed in the through hole, the limiting ring is provided with an annular stop ring, and the limiting rod is used to cooperate with the annular stop ring to one-way limit the limiting ring. In this way, the limiting rod can be pre-installed and limited, and when the mechanical seal is installed, the pump shaft can be one-way limited by the limiting rod, and then the mechanical seal is fixed by the annular pressing plate; when the nuclear lead-bismuth pump is in normal use, the limiting rod needs to be rotated out to the outermost side.

[0010] Preferably, the dynamic ring assembly includes a first dynamic ring, a second dynamic ring and a dynamic ring seat, the dynamic ring seat is sleeved with the shaft sleeve, springs connected with the dynamic ring seat are installed on the first dynamic ring and the second dynamic ring, one end of the first dynamic ring away from the spring abuts against the first static ring, and one end of the second dynamic ring away from the spring abuts against the second static ring. In this way, the springs can drive the first dynamic ring and the second dynamic ring to dynamically seal with the first static ring and the second static ring respectively, and the springs can self-adaptively adjust the position balance of the first dynamic ring and the second dynamic ring to avoid the dynamic ring assembly from being stuck with the first static ring or the second static ring.

[0011] Preferably, the connecting seat and the annular pressing plate are both provided with sealing mechanisms for sealing the first static ring and the second static ring. In this way, the sealing mechanisms can further improve the sealing performance of the first static ring and the second static ring.

[0012] Preferably, the sealing mechanism comprises a sealing groove and a sealing ring installed in the sealing groove, and the bottom of the sealing groove is polished. In this way, the sealing ring can be pressed against the sealing groove when the first static ring or the second static ring is installed, thereby avoiding gas leakage.

[0013] Preferably, a wall sleeve for heat dissipation is arranged in the connecting seat, and a bellows is arranged on the wall sleeve. In this way, the heat exchange area can be increased through the bellows, thereby improving the heat dissipation effect of the wall sleeve.

[0014] Preferably, a throttling ring is arranged on the matching surface of the shaft sleeve and the annular pressing plate, and the material of the throttling ring comprises metal. In this way, the throttling ring can temporarily seal in the early stage of mechanical seal failure, thereby avoiding medium leakage to the outside and reducing the risk generated when the mechanical seal fails.

[0015] Preferably, a through hole that is in communication with the inside of the shell is arranged on the annular pressing plate, and a temperature sensor is installed in the through hole. In this way, the temperature sensor can be used to monitor the temperature in the cavity in real time, and the user can be reminded to adjust or repair when the temperature is abnormal.

[0016] Compared with the prior art, the application has the following beneficial effects:

[0017] The dynamic ring assembly can dynamically seal the two ends of the shaft sleeve in cooperation with the first static ring and the second static ring, thereby further improving the effect of mechanical seal. The parking sealing mechanism can replace the mechanical seal structure as a whole without stopping the machine, and the installation cavity can be inflated to drive the top block to move upward. At this time, the first sealing ring abuts against the limiting ring and seals the cavity, thereby not only improving the replacement speed of the mechanical seal but also maintaining the air tightness of the sealing cavity and ensuring that the work of the nuclear lead bismuth pump is not affected.

[0018] The reset mechanism can reset the top block. After the mechanical seal is replaced, the gas in the installation cavity is discharged, and the reset mechanism drives the top block to reset, thereby improving the installation speed of the mechanical seal. In addition, the throttling ring can temporarily seal, thereby avoiding medium leakage to the outside and reducing the risk generated when the mechanical seal fails. The temperature sensor can monitor the temperature in the cavity in real time, and the user can be reminded to adjust or repair when the temperature is abnormal. The utility model has the advantages of high sealing performance, good safety and convenient replacement. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a whole cross-sectional structure schematic view of the sealing structure of the nuclear lead bismuth pump in the application.

[0020] Figure 2 It is a local cross-sectional structure schematic view of the sealing structure of the nuclear lead bismuth pump in the application.

[0021] Figure 3 For Figure 2 Enlarged structural schematic view of the middle part A.

[0022] In the figure: 1, housing; 11, wall sleeve; 100, first static ring; 2, connecting seat; 200, second static ring; 3, annular pressing plate; 300, shaft sleeve; 301, pump shaft; 4, dynamic ring assembly; 41, first dynamic ring; 42, second dynamic ring; 43, spring; 44, dynamic ring seat; 400, limiting ring; 401, annular retainer; 5, mounting seat; 51, mounting cavity; 500, elastic member; 6, top block; 61, first sealing ring; 62, second sealing ring; 600, limiting rod; 7, base; 71, inflation port; 700, throttle ring; 8, temperature sensor; 800, sealing groove; 801, sealing ring. DETAILED DESCRIPTION

[0023] Hereinafter, the present application will be further described in conjunction with specific embodiments, and it should be noted that, without conflict, the following described embodiments or technical features between each other or between each other can be arbitrarily combined to form new embodiments.

[0024] In the description of the present application, it should be noted that, for orientation words, such as the terms "center", "transverse", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. The orientation and positional relationship shown in the drawing is based on the orientation or positional relationship, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and cannot be understood as limiting the specific protection scope of the present application.

[0025] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application are used to distinguish similar objects, and do not necessarily have to describe a specific order or chronological order.

[0026] The terms "include" and "have" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] One aspect of the present application provides a mechanical seal structure for a nuclear lead-bismuth pump, wherein a preferred embodiment is as follows Figure 1As shown, the shaft sleeve 300 and the pump shaft 301 sleeved with the shaft sleeve 300 are shown, the shaft sleeve 300 is fixedly connected with the pump shaft 301 to protect the pump shaft 301. The shell 1 is sleeved with the shaft sleeve 300, the shell 1 is internally communicated and two ends thereof are respectively provided with the connecting seat 2 and the annular pressing plate 3, the annular pressing plate 3 is cooperatively installed with the shaft sleeve 300 and limits the pump shaft 301. The dynamic ring assembly 4 is sealingly installed on the shaft sleeve 300, the first static ring 100 is installed on the connecting seat 2, the second static ring 200 is installed on the annular pressing plate 3, the first static ring 100 and the second static ring 200 cooperatively form a sealing surface with the dynamic ring assembly 4, which can further improve the mechanical sealing effect and avoid leakage of the medium in the shell 1 when the pump shaft 301 rotates.

[0028] Further, as shown in the figure, Figure 1 The connecting seat 2 is further provided with a parking sealing mechanism, the parking sealing mechanism comprises a mounting seat 5, a top block 6 and a base 7, the mounting seat 5 is provided with a mounting cavity 51, the top block 6 is slidingly installed in the mounting cavity 51, the base 7 cooperatively supports the top block 6 with the mounting seat 5, the top block 6 is provided with a first sealing ring 61 and a second sealing ring 62, wherein the second sealing ring 62 is installed at the lower part of the top block 6 and can cooperatively seal the mounting cavity 51 with the inner wall of the base 7. The base 7 is provided with an inflation port 71 communicated with the mounting cavity 51, and the mounting cavity 51 is provided with a limiting ring 400 sealingly connected with the pump shaft 301. When replacing the mechanical seal, the mounting cavity 51 is inflated through the inflation port 71 to drive the top block 6 to move upward, at this time, the first sealing ring 61 abuts against the limiting ring 400 and seals the cavity. Not only can the replacement speed of the mechanical seal be improved, but also the air tightness of the sealing cavity can be maintained to ensure that the work of the nuclear lead bismuth pump is not affected.

[0029] It can be understood that in the prior art, the mechanical seal often needs to be replaced after the machine is stopped, and the sealing inspection needs to be performed again after the replacement is completed, which not only complicates the operation, but also affects the working efficiency of the machine. The parking sealing mechanism in the present application can replace the mechanical seal as a whole without stopping the machine, which can replace the mechanical seal while maintaining the air tightness of the machine, further improving the maintenance efficiency of the nuclear lead bismuth pump.

[0030] In the embodiment, as shown in the figure, Figure 1 The top block 6 is provided with a reset mechanism for pushing the top block 6 to move. After the replacement of the mechanical seal is completed, the gas in the mounting cavity 51 is discharged through the inflation port 71, and then the reset mechanism drives the top block 6 to return to the initial position, thereby improving the replacement efficiency of the mechanical seal and ensuring that the nuclear lead bismuth pump can quickly return to the working state after the mechanical seal is connected with the mounting seat 5.

[0031] Specifically, as shown in the figure, Figure 1As shown, the reset mechanism includes an elastic member 500, the top block 6 is provided with a groove near one end of the limiting ring 400, one end of the elastic member 500 is installed in the groove, and the other end abuts against the inner wall of the mounting seat 5. When the connecting seat 2 is connected with the mounting seat 5, the top block 6 can be reset by the elastic member 500; when the top block 6 moves towards the limiting ring 400, the elastic member 500 is compressed and stores elasticity; when the air pressure below the top block 6 decreases, the elastic member 500 drives the top block 6 to reset by its own elastic force. The specific specifications and size of the elastic member 500 can be adjusted by the person skilled in the art according to the actual needs, as long as the elastic member 500 can drive the top block 6 to move by its own elastic force. Of course, in order to make the movement of the top block 6 more stable, the number of elastic members 500 can be multiple, and the multiple elastic members 500 are distributed equidistantly around the central axis of the top block 6.

[0032] In this embodiment, as shown in Figure 1 The mounting seat 5 is provided with a through hole communicating with the mounting cavity 51, the limiting rod 600 is slidingly installed in the through hole, and the limiting ring 400 is provided with an annular stop ring 401; when the limiting rod 600 extends into the mounting cavity 51, the end of the limiting rod 600 can cooperate with the annular stop ring 401 to support the limiting ring 400 vertically upward, so as to ensure that the position of the pump shaft 301 does not deviate when the mechanical seal is removed. Further, the limiting rod 600 and the through hole are provided with limiting structures matched with each other, which include but are not limited to interference fit and threaded fit, as long as the limiting rod 600 can only be moved by manual operation; in addition, in order to avoid foreign matter and gas entering the mounting cavity 51, a sealing structure should be provided in the limiting rod 600 or the through hole.

[0033] It can be understood that the limiting rod 600 can be pre-installed, when the mechanical seal is installed, the pump shaft 301 is first limited in one direction by the limiting rod 600, and then the mechanical seal is fixed by the annular pressing plate 3; when the lead-bismuth pump is used normally, the limiting rod 600 needs to be rotated out to the outermost side.

[0034] In this embodiment, as shown in Figure 1 and Figure 2As shown, the dynamic ring assembly 4 comprises a first dynamic ring 41, a second dynamic ring 42 and a dynamic ring seat 44, the dynamic ring seat 44 is sealed to the outside of the shaft sleeve 300, the first dynamic ring 41 and the second dynamic ring 42 are both provided with springs 43 connected with the dynamic ring seat 44; wherein the end of the first dynamic ring 41 away from the spring 43 abuts against the first static ring 100, and the end of the second dynamic ring 42 away from the spring 43 abuts against the second static ring 200, so as to ensure that the spring 43 can elastically support the first dynamic ring 41 and the second dynamic ring 42 respectively. When the first dynamic ring 41 and the second dynamic ring 42 are installed, the spring 43 can drive the first dynamic ring 41 and the second dynamic ring 42 to dynamically seal with the first static ring 100 and the second static ring 200 respectively, and when the machine vibrates, the spring 43 can self-adaptively adjust the position balance of the first dynamic ring 41 and the second dynamic ring 42, so as to avoid the dynamic ring assembly 4 from being stuck with the first static ring 100 or the second static ring 200.

[0035] Further, the connecting seat 2 and the annular pressing plate 3 are both provided with sealing mechanisms, which are used for sealing the first static ring 100 and the second static ring 200, so as to avoid gas leakage through the installation positions of the first static ring 100 and the second static ring 200, and further improve the sealing performance of the first static ring 100 and the second static ring 200.

[0036] Specifically, as shown in Figure 2 and Figure 3 , the sealing mechanism comprises a sealing groove 800 and a sealing ring 801 installed in the sealing groove 800, and the sealing ring 801 can be pressed to tightly adhere to the sealing groove 800 when the first static ring 100 or the second static ring 200 is installed, so as to avoid gas leakage. In addition, the bottom of the sealing groove 800 is ground treated, so as to improve the high-temperature resistance and high-pressure resistance of the sealing groove 800, and ensure that the nuclear lead-bismuth pump has good sealing effect at high temperature.

[0037] In the embodiment, as shown in Figure 2 , the connecting seat 2 is provided with a wall sleeve 11 for heat dissipation, and the wall sleeve 11 is provided with a bellows, which can further increase the heat exchange area and improve the heat dissipation effect of the wall sleeve 11. Further, the mating surfaces of the shaft sleeve 300 and the annular pressing plate 3 are both provided with a throttling ring 700, and the material of the throttling ring 700 includes but is not limited to metal; in the early stage of mechanical seal failure, the throttling ring 700 can temporarily seal, so as to avoid medium leakage to the outside and reduce the risk generated when the mechanical seal fails.

[0038] In the embodiment, as shown in Figure 2 , the annular pressing plate 3 is provided with a through hole communicated with the inside of the shell 1, and a temperature sensor 8 is installed in the through hole, which can monitor the temperature in the cavity in real time, and remind the user to adjust and repair when the temperature is abnormal, and further improve the operation stability of the nuclear lead-bismuth pump.

[0039] The foregoing describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-described embodiments, and the above-described embodiments and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A mechanical seal structure for a nuclear lead-bismuth pump, comprising a shaft sleeve (300) and a pump shaft (301) which is fitted into the shaft sleeve (300), characterized in that The shaft sleeve (300) is sleeved with a shell (1), two ends of the shell (1) are respectively provided with a connecting seat (2) and an annular pressing plate (3), the shaft sleeve (300) is sealingly connected with a dynamic ring assembly (4), the connecting seat (2) is provided with a first static ring (100), the annular pressing plate (3) is provided with a second static ring (200), the first static ring (100) and the second static ring (200) cooperate with the dynamic ring assembly (4) to form a sealing surface; A parking sealing mechanism is mounted on the connecting seat (2), the parking sealing mechanism comprises a mounting seat (5), a top block (6) and a base (7), the mounting seat (5) is provided with a mounting cavity (51) therein, the top block (6) is slidingly mounted in the mounting cavity (51), and the base (7) supports the top block (6) in cooperation with the mounting seat (5); the top block (6) is provided with a first sealing ring (61) and a second sealing ring (62), the second sealing ring (62) cooperates with the inner wall of the base (7) to seal, the base (7) is provided with an inflation port (71) communicated with the mounting cavity (51), and the mounting cavity (51) is provided with a limiting ring (400) connected with the pump shaft (301); the top block (6) drives the first sealing ring (61) to extrude the limiting ring (400) to seal by moving itself.

2. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein A reset mechanism is arranged on the top block (6), and the reset mechanism is used for pushing the top block (6) to move.

3. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 2, wherein The reset mechanism comprises an elastic member (500), one end of the top block (6) close to the limiting ring (400) is provided with a groove, one end of the elastic member (500) is mounted in the groove, and the other end abuts against the inner wall of the mounting seat (5).

4. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein The mounting seat (5) is provided with a through hole communicated with the mounting cavity (51), and a limiting rod (600) is slidingly mounted in the through hole, the limiting ring (400) is provided with an annular stop ring (401), and the limiting rod (600) is used for cooperating with the annular stop ring (401) to one-way limit the limiting ring (400).

5. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein The dynamic ring assembly (4) comprises a first dynamic ring (41), a second dynamic ring (42) and a dynamic ring seat (44), the dynamic ring seat (44) is sleeved with the shaft sleeve (300), springs (43) connected with the dynamic ring seat (44) are mounted on the first dynamic ring (41) and the second dynamic ring (42), one end of the first dynamic ring (41) away from the spring (43) abuts against the first static ring (100), and one end of the second dynamic ring (42) away from the spring (43) abuts against the second static ring (200).

6. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 5, wherein Sealing mechanisms are arranged on the connecting seat (2) and the annular pressing plate (3), and the sealing mechanisms are used for sealing the first static ring (100) and the second static ring (200).

7. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 6, wherein The sealing mechanism comprises a sealing groove (800) and a sealing ring mounted in the sealing groove (800), and the bottom of the sealing groove (800) is ground.

8. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein The connecting seat (2) is internally provided with a wall sleeve (11) for heat dissipation, and the wall sleeve (11) is provided with a bellows.

9. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein The matching surface of the shaft sleeve (300) and the annular pressing plate (3) is provided with a throttle ring (700), and the material of the throttle ring (700) comprises metal.

10. The mechanical seal structure for a nuclear power lead-bismuth pump according to claim 1, wherein The annular pressing plate (3) is provided with a through hole in communication with the inside of the shell (1), and a temperature sensor (8) is installed in the through hole.

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