A kind of silt shaft seal for nuclear power plant heat trap system circulating water pump

Abstract

The application discloses a kind of for nuclear power plant heat sink system circulating water pump silt shaft seal, it is related to nuclear power circulating water pump technical field, it includes the packing base being arranged in the outside of main shaft, packing sleeve, packing, sand ring, packing box and packing gland, the packing sleeve is fixedly arranged on packing base, the packing is arranged in packing sleeve, the packing box is fixedly arranged on the top of packing sleeve, the packing gland is arranged in packing box and packing is compressed in packing sleeve, the sand ring is arranged in packing sleeve, the sand ring is located below packing close to packing base, the sand ring inside abuts and fits the outside of main shaft. The sand ring of the application installed in packing sleeve can prevent silt from entering packing, reduce the wear of packing during the operation of water pump, so as to improve the service life and reliability of circulating water pump.

Description

Technical Field

[0001] This application relates to the field of nuclear power circulating water pump technology, and in particular to a mud and sand shaft seal for a circulating water pump in a nuclear power plant heat trap system. Background Technology

[0002] The main function of the circulating water system is to provide the heat exchangers of the turbine condenser and the auxiliary cooling water system of the conventional island with the required cooling water flow rate during unit operation. The main shaft seal of the circulating water pump usually adopts a packing seal structure, and its reliability, maintainability, and economy have a critical impact on ensuring the safe and stable operation of the circulating water pump.

[0003] When nuclear power plants are located in water bodies with high sediment content, the main shaft seals of circulating water pumps operate in a water environment containing suspended particulate matter for extended periods. Under current technological conditions, the main problems are as follows: Sediment particles easily intrude into the contact area of ​​the sealing surfaces, causing abrasive wear at the sealing interface, thereby accelerating the wear of the sealing material and significantly shortening its service life. Summary of the Invention

[0004] In order to improve the service life of the shaft seal of the circulating water pump, this application provides a mud and sand shaft seal for the circulating water pump of the heat trap system in a nuclear power plant.

[0005] The mud and sand shaft seal for a circulating water pump in a nuclear power plant heat sink system provided in this application adopts the following technical solution:

[0006] A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system includes a packing base, a packing sleeve, packing, a sand-proof ring, a stuffing box, and a packing gland disposed on the outside of the main shaft. The packing sleeve is fixedly disposed on the packing base, the packing is disposed inside the packing sleeve, the stuffing box is fixedly disposed on the top of the packing sleeve, the packing gland is disposed inside the stuffing box and presses the packing into the packing sleeve, and the sand-proof ring is disposed inside the packing sleeve. The sand-proof ring is located below the packing near the packing base, and the inner side of the sand-proof ring abuts against and fits against the outer side of the main shaft.

[0007] By adopting the above technical solution, the sand-proof ring installed in the packing sleeve can prevent mud and sand from entering the packing, reduce the wear of the packing during the operation of the water pump, and thus improve the service life and reliability of the circulating water pump.

[0008] Preferably, the sand-proof ring includes a main ring body and a sealing ring body. The two ends of the main ring body along the axial direction of the main shaft respectively abut against the packing base and the packing. The sealing ring body is disposed on the inner side of the main ring body and is interference-fitted with the outer side wall of the main shaft.

[0009] By adopting the above technical solution, the packing packing presses the main ring body tightly onto the packing base, and the sealing ring body is interference-fitted against the outer wall of the main shaft, thereby preventing mud and sand from entering the packing packing.

[0010] Preferably, the inner wall of the packing base is provided with a water inlet channel, the sealing ring is inclinedly disposed inside the main ring, the end of the sealing ring away from the main ring is interference-fitted with the outer wall of the main shaft, and a buffer cavity is formed between the sealing ring and the main ring.

[0011] By adopting the above technical solution, the silt enters the packing base from the water inlet channel. The sealing ring blocks the silt, so that the silt is temporarily stored in the buffer cavity. At the same time, when the silt impacts the inclined sealing ring, it can push the end of the sealing ring to press against the main shaft, thereby improving the sealing effect of the sealing ring.

[0012] Preferably, two mounting rings are spaced apart on the outer side wall of the main ring body, and both mounting rings abut against the inner side wall of the packing sleeve.

[0013] By adopting the above technical solution, the outer side of the main ring body abuts against the inner wall of the packing sleeve through the installation ring, thereby making the sealing effect of the inner sealing ring of the main ring body better.

[0014] Preferably, the packing sleeve has a liquid inlet in its side wall, which communicates with the inner cavity of the packing sleeve, and the packing gland has a liquid outlet in its side wall, which communicates with the inner cavity of the packing sleeve.

[0015] By adopting the above technical solution, the coolant enters the packing sleeve through the inlet and cools the packing packing. The coolant, after absorbing heat, is discharged through the outlet.

[0016] Preferably, multiple packing packings are arranged along the axial direction of the main shaft, two heat-conducting rings are arranged between two adjacent packing packings, multiple support blocks are arranged between two heat-conducting rings, annular flow channels are formed on the inner side of the support blocks and the heat-conducting rings, and a liquid inlet flow channel is formed between two adjacent support blocks, with the two ends of the liquid inlet flow channel respectively connected to the liquid inlet and the annular flow channel.

[0017] By adopting the above technical solution, the coolant flows into the annular flow channel through the inlet and the inlet channel. The coolant flows upward and is cooled after passing through the packing. Then it is discharged from the outlet. When the anti-sand ring fails, the coolant flows downward, which can block the flow of mud and sand, thus forming a secondary sand prevention.

[0018] Preferably, each of the support blocks has an arc-shaped flow channel, which is connected to the liquid inlet channel.

[0019] By adopting the above technical solution, the coolant flows within the arc-shaped flow channel, thereby improving the cooling effect of the coolant.

[0020] Preferably, multiple pressure blocks are fixedly arranged at equal intervals along the circumference of the outer side wall of the packing gland, and each of the multiple pressure blocks is provided with a connector, the bottom end of the connector being threaded inside the packing gland.

[0021] By adopting the above technical solution, the pressure block and stuffing gland are connected using connectors, thereby enabling adjustment of the tightness of the stuffing gland.

[0022] Preferably, the main ring body is provided with multiple sand discharge pipes at equal intervals along its circumference. The bottom end of the sand discharge pipe is connected to the buffer cavity, and the top end of the sand discharge pipe passes through the packing, heat conduction ring, and support block and is connected to the arc-shaped flow channel. The bottom end of the sand discharge pipe is rotatably provided with a cap, and an elastic element is provided inside the sand discharge pipe to drive the cap to close the sand discharge pipe.

[0023] By adopting the above technical solution, the elastic element drives the cover to rotate and close the sand discharge pipe, so that the mud and sand will not enter the sand discharge pipe. When a lot of mud and sand are stored in the buffer chamber, the inlet flow rate of the coolant is increased. The coolant pushes the cover to rotate and open. At this time, the coolant in the sand discharge pipe enters the buffer chamber and then flows out from the water inlet channel. During the flow of coolant, the mud and sand in the buffer chamber can be carried out together, thereby cleaning the mud and sand in the buffer chamber.

[0024] Preferably, the sand-proof ring is provided with multiple baffles at equal intervals along its circumference inside the buffer cavity, the multiple baffles divide the buffer cavity into multiple chambers, the multiple sand discharge pipes are respectively connected to the multiple chambers, the two sides of the baffles are respectively connected to the main ring body and the sealing ring body, the bottom end of the baffle is inclined along the circumference of the sand-proof ring, the multiple sand discharge pipes are respectively located above the multiple baffles, and a gap is formed between the baffles and the main shaft.

[0025] By adopting the above technical solution, the baffles reinforce the sealing ring body, further improving the sealing effect of the sealing ring body; multiple baffles divide the buffer chamber into multiple independent chambers, and multiple sand discharge pipes connect to multiple chambers respectively. After the coolant enters the buffer chamber from the sand discharge pipe, it impacts the inclined baffles. Under the action of the baffles, the coolant flows along the inclined direction of the baffles, which facilitates the discharge of mud and sand. At the same time, the gap between the baffles and the spindle can connect two adjacent chambers, preventing mud and sand from accumulating at the baffles.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. By using the sand-blocking ring installed inside the packing sleeve to block mud and sand, it is possible to prevent mud and sand from entering the packing, reduce the wear of the packing during the operation of the water pump, and thus improve the service life and reliability of the circulating water pump.

[0028] 2. With the help of the annular flow channel, the coolant flows into the annular flow channel through the inlet and the inlet flow channel. The coolant flows upward and is cooled after passing through the packing. Then it is discharged from the outlet. When the anti-sand ring fails, the coolant flows downward, which can block the flow of mud and sand, thus forming a secondary sand prevention.

[0029] 3. When a lot of mud and sand are stored in the buffer chamber, the inlet flow rate of the coolant is increased through the sand discharge pipe. The coolant pushes the cap to rotate and open. At this time, the coolant in the sand discharge pipe enters the buffer chamber and then flows out from the water inlet channel. During the outflow of the coolant, the mud and sand in the buffer chamber can be carried out together, thereby cleaning the mud and sand in the buffer chamber. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the overall structure of the mud and sand shaft seal used in the circulating water pump of the heat sink system in a nuclear power plant, as described in Embodiment 1 of this application.

[0031] Figure 2 For this application Figure 1 Enlarged view of point A in the middle;

[0032] Figure 3 For this application Figure 1 Enlarged view of point B in the middle;

[0033] Figure 4 This is a partial structural cross-sectional view of the mud and sand shaft seal used in the circulating water pump of the heat sink system in a nuclear power plant, as described in Embodiment 2 of this application.

[0034] Figure 5 This is a partial structural diagram of the mud and sand shaft seal used in the circulating water pump of the heat sink system in a nuclear power plant, as shown in Embodiment 2 of this application.

[0035] Figure 6 This is a partial structural cross-sectional view of the mud and sand shaft seal used in the circulating water pump of the heat sink system in a nuclear power plant, as described in Embodiment 2 of this application.

[0036] Reference numerals: 1. Main shaft; 2. Packing base; 3. Packing sleeve; 4. Packing packing; 5. Sand-proof ring; 51. Main ring body; 52. Sealing ring body; 6. Stuffing box; 7. Packing gland; 8. Water inlet channel; 9. Buffer chamber; 10. Mounting ring; 11. Liquid inlet; 12. Liquid outlet; 13. Heat-conducting ring; 14. Support block; 15. Annular flow channel; 16. Arc-shaped flow channel; 17. Pressure block; 18. Connector; 19. Sand discharge pipe; 20. Cover; 21. Elastic element; 22. Baffle; 23. Gap; 24. Liquid inlet channel. Detailed Implementation

[0037] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0038] This application discloses a mud and sand shaft seal for a circulating water pump in a nuclear power plant heat sink system.

[0039] Reference Figure 1 , Figure 2 and Figure 3 A sludge shaft seal for a circulating water pump in a nuclear power plant heat trap system includes a packing base 2, a packing sleeve 3, packing 4, a sand-proof ring 5, a stuffing box 6, and a packing gland 7, all installed on the outside of a main shaft 1. The bottom end of the packing sleeve 3 is fixedly connected to the packing base 2, which is fitted onto the main shaft 1. Five packing 4 are installed inside the packing sleeve 3 and fitted onto the main shaft 1.

[0040] The top end of the packing sleeve 3 is fixedly connected to the stuffing box 6, and the packing gland 7 is slidably sleeved on the main shaft 1, with the bottom end of the packing gland 7 abutting against the packing 4. Multiple pressure blocks 17 are fixedly connected at equal intervals along the circumference of the outer wall of the packing gland 7. Each pressure block 17 has a connector 18 installed inside, and the connector 18 is threadedly fixedly connected to the stuffing box 6. In this application, the connector 18 can be a bolt and a nut. The connector 18 is used to fix the pressure blocks 17 and the stuffing box 6, allowing the packing gland 7 to press the packing 4 tightly. Simultaneously, the tightness of the packing 4 can be adjusted by adjusting the tightness of the connector 18.

[0041] The sand-proof ring 5 is installed inside the packing sleeve 3, and is located below the five packing packings 4. The sand-proof ring 5 includes a main ring body 51 and a sealing ring body 52. ​​The upper and lower ends of the main ring body 51 abut against the packing packing 4 and the packing base 2 respectively in the axial direction. Two mounting rings 10 are integrally formed on the outer side wall of the main ring body 51, and the two mounting rings 10 abut against the inner side wall of the packing sleeve 3.

[0042] The sealing ring 52 is integrally formed inside the main ring 51. The bottom of the sealing ring 52 is inclined towards the main shaft 1, and the bottom end of the sealing ring 52 abuts against the outer wall of the main shaft 1, with an interference fit between the bottom end of the sealing ring 52 and the outer wall of the main shaft 1. In this application, both the main ring 51 and the sealing ring 52 can be made of rubber material.

[0043] A water inlet channel 8 is formed between the inner wall of the packing base 2 and the outer wall of the main shaft 1. An annular buffer cavity 9 is formed between the main ring body 51 and the sealing ring body 52, and the buffer cavity 9 is connected to the water inlet channel 8. After entering the packing base 2 through the water inlet channel 8, the sediment is blocked by the sealing ring body 52 and temporarily retained inside the buffer cavity. This prevents sediment from entering the packing 4, reducing the wear of the packing 4 during pump operation, thereby improving the service life and reliability of the circulating water pump. At the same time, the sediment impacts the inclined sealing ring body 52, which in turn pushes the bottom end of the sealing ring body 52 to further press against the main shaft 1, forming a dynamic self-tightening seal, effectively improving the sealing performance of the sand-proof ring 5.

[0044] Two heat-conducting rings 13 are installed inside the packing sleeve 3, and the upper and lower sides of the two heat-conducting rings 13 respectively abut against the third and fourth packing packing 4. Two arc-shaped support blocks 14 are installed at intervals along their circumference inside the packing sleeve 3, and the upper and lower sides of the two support blocks 14 abut against the two heat-conducting rings 13 respectively.

[0045] An inlet 11 is provided in the middle of the outer side wall of the packing sleeve 3, and the inlet 11 is connected to the circulating liquid supply equipment through a pipeline. Two outlets 12 are symmetrically provided on the outer side wall of the packing gland 7, and the outlets 12 are connected to the circulating liquid supply equipment through pipelines, and the outlets 12 are in communication with the inner cavity of the packing sleeve 3.

[0046] A liquid inlet channel 24 is formed between the two support blocks 14, and the liquid inlet channel 24 is connected to the liquid inlet 11. Each support block 14 has an arc-shaped channel 16 formed along its own arc direction, and the end of the arc-shaped channel 16 is connected to the liquid inlet channel 24. An annular channel 15 is formed on the inner side of both support blocks 14 and the heat-conducting ring 13, and the annular channel 15 is connected to the liquid inlet channel 24.

[0047] Coolant is injected into the annular flow channel 15 through the inlet 11 and the inlet channel 24, flows axially upward and penetrates the three packing packings 4 to complete the cooling operation, and then is discharged through the outlet 12. When the sand-proof ring 5 fails, the coolant flows axially upward and downward simultaneously, using the fluid barrier effect to block the intrusion path of mud and sand media, and realizes the secondary sand-proof protection function.

[0048] The implementation principle of a sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to an embodiment of this application is as follows: The anti-sand ring 5 installed inside the packing sleeve 3 serves as a pre-protective barrier for the main shaft 1 sealing system. The sealing ring 52 effectively prevents sludge particles contained in the cooling water from entering the subsequent packing 4 sealing area, directly reducing abrasive wear between the packing 4 and the main shaft 1. Simultaneously, when the anti-sand ring 5 fails, the coolant flows axially upwards and downwards simultaneously, utilizing the fluid barrier effect to block the intrusion path of the sludge medium, thus achieving secondary sand protection.

[0049] Example 2:

[0050] Reference Figure 4 , Figure 5 and Figure 6 The difference between this embodiment and Embodiment 1 is that multiple sand discharge pipes 19 are fixedly installed at equal intervals along the circumference of the top of the main ring body 51. The top end of the sand discharge pipe 19 passes through two layers of packing 4, the heat-conducting ring 13, and the support block 14, and then communicates with the arc-shaped flow channel 16. The bottom end of the sand discharge pipe 19 passes through the main ring body 51 and then communicates with the buffer cavity 9. The coolant in the arc-shaped flow channel 16 can flow into the buffer cavity 9 through the sand discharge pipes 19.

[0051] Each sand discharge pipe 19 has a cap 20 rotatably installed at its bottom end. An elastic element 21 is installed inside the bottom end of the sand discharge pipe 19. In this application, the elastic element 21 can be a spring sheet. The elastic element 21 is L-shaped, and its two ends are respectively fixedly embedded inside the sand discharge pipe 19 and on the top wall of the cap 20. When the coolant is transported at normal pressure, the elastic element 21 drives the cap 20 to close the bottom end of the sand discharge pipe 19; when the coolant is transported at high pressure, the coolant pushes the cap 20 to rotate and open the sand discharge pipe 19.

[0052] Multiple baffles 22 are fixedly installed at equal intervals along the circumference of the sand-proof ring 5. The two sides of the baffles 22 are integrally formed with the main ring body 51 and the sealing ring body 52, respectively, and the bottom end of the baffles 22 abuts against the packing base 2. The baffles 22 support and reinforce the sealing ring body 52, thereby further improving the sealing effect of the sealing ring body 52.

[0053] The baffle 22 divides the annular buffer chamber 9 into multiple spaced chambers, and multiple sand discharge pipes 19 are located above the multiple baffles 22 and communicate with the multiple chambers. The bottom of the baffle 22 is installed at an angle along the circumference of the sand-proof ring 5, and a gap 23 is formed between the bottom of the baffle 22 and the main shaft 1. The width of the gap 23 is greater than the width of the water inlet channel 8.

[0054] The implementation principle of Embodiment 2 of this application is as follows: When the amount of silt accumulated in the buffer chamber reaches a threshold, the driving force is generated by increasing the coolant inlet flow rate, which pushes the cover 20 to rotate and open. At this time, the coolant in the sand discharge pipe 19 is injected into the buffer chamber and impacts the inclined baffle 22 structure in the chamber. Under the guiding effect of the baffle 22, the coolant forms a directional flow along the inclined angle of the baffle 22 and is finally discharged through the water inlet channel 8. During the flow of the coolant, the fluid carrying effect is used to drive the silt accumulated in the buffer chamber to be discharged synchronously, realizing the silt cleaning operation of the buffer chamber. At the same time, the gap 23 structure reserved between the baffle 22 and the main shaft 1 can realize the fluid communication between adjacent chambers, effectively avoiding the formation of local accumulation of silt in the baffle 22 area and ensuring unobstructed flow.

[0055] The above are merely optional embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system, characterized in that: The assembly includes a packing base (2), a packing sleeve (3), a packing packing (4), a sand-proof ring (5), a stuffing box (6), and a packing gland (7) located on the outside of the main shaft (1). The packing sleeve (3) is fixedly mounted on the packing base (2). The packing packing (4) is located inside the packing sleeve (3). The stuffing box (6) is fixedly mounted on the top of the packing sleeve (3). The packing gland (7) is located inside the stuffing box (6) and presses the packing packing (4) tightly inside the packing sleeve (3). The sand-proof ring (5) is located inside the packing sleeve (3) and is positioned below the packing packing (4) near the packing base (2). The inner side of the sand-proof ring (5) abuts against and fits against the outer side of the main shaft (1). The sand-proof ring (5) includes a main ring body (51) and a sealing ring body (52). A buffer cavity (9) is formed between the sealing ring body (52) and the main ring body (51). Multiple sand discharge pipes (19) are evenly spaced along the circumference of the main ring body (51). The bottom end of the sand discharge pipes (19) is connected to the buffer cavity (9). The sand-proof ring (5) is located in the buffer cavity (9) and has multiple baffles (22) evenly spaced along its circumference. The plate (22) divides the buffer cavity (9) into multiple cavities, and multiple sand discharge pipes (19) are connected to multiple cavities respectively. The two sides of the baffle (22) are connected to the main ring body (51) and the sealing ring body (52) respectively. The bottom end of the baffle (22) is inclined along the circumference of the sand-proof ring (5). Multiple sand discharge pipes (19) are located above multiple baffles (22) respectively. A gap (23) is formed between the baffle (22) and the main shaft (1). Two heat-conducting rings (13) are provided between two adjacent packings (4), and multiple support blocks (14) are provided between the two heat-conducting rings (13). Each support block (14) has an arc-shaped flow channel (16). The top end of the sand discharge pipe (19) passes through the packings (4), the heat-conducting rings (13), the support blocks (14) and communicates with the arc-shaped flow channel (16). The bottom end of the sand discharge pipe (19) is rotatably provided with a cap (20). An elastic element (21) is provided inside the sand discharge pipe (19) to drive the cap (20) to close the sand discharge pipe (19).

2. The sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 1, characterized in that: The main ring body (51) abuts against the packing base (2) and the packing packing (4) at both ends along the axial direction of the main shaft (1), and the sealing ring body (52) is disposed on the inner side of the main ring body (51), and the sealing ring body (52) is interference-fitted with the outer side wall of the main shaft (1).

3. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 2, characterized in that: The inner wall of the packing base (2) is provided with a water inlet channel (8), and the sealing ring (52) is inclinedly arranged inside the main ring (51). The end of the sealing ring (52) away from the main ring (51) is interference-fitted with the outer wall of the main shaft (1).

4. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 2, characterized in that: Two mounting rings (10) are spaced apart on the outer side wall of the main ring body (51), and both mounting rings (10) abut against the inner side wall of the packing sleeve (3).

5. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 3, characterized in that: The packing sleeve (3) has an inlet (11) in the side wall, which is connected to the inner cavity of the packing sleeve (3). The packing gland (7) has an outlet (12) in the side wall, which is connected to the inner cavity of the packing sleeve (3).

6. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 5, characterized in that: Multiple packing packings (4) are arranged along the axial direction of the main shaft (1). Both the inner side of the support block (14) and the heat-conducting ring (13) are formed with annular flow channels (15). A liquid inlet flow channel (24) is formed between two adjacent support blocks (14). The two ends of the liquid inlet flow channel (24) are respectively connected to the liquid inlet (11) and the annular flow channel (15).

7. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 6, characterized in that: The arc-shaped flow channel (16) is connected to the liquid inlet flow channel (24).

8. A sludge shaft seal for a circulating water pump in a nuclear power plant heat sink system according to claim 1, characterized in that: Multiple pressure blocks (17) are fixedly arranged at equal intervals along the circumference of the outer side wall of the packing gland (7). Each of the multiple pressure blocks (17) is provided with a connector (18), and the bottom end of the connector (18) is threaded inside the packing gland (6).

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