Spent fuel pool cooling pump mechanical seal

Abstract

The utility model belongs to the field of mechanical seals, and particularly relates to a spent fuel pool cooling pump mechanical seal which comprises a rotating assembly, a static ring, a static ring sealing ring, a gland assembly, a positioning block, a bolt, a transmission ring assembly, a pump shaft, a pump body, a nut and a stud. A static ring sealing ring is arranged between the static ring and the gland assembly and is pressed on the step of the gland assembly through the static ring to form a sealing point; the positioning block is fastened to the end face of the gland assembly through a bolt, the end, away from the bolt, of the positioning block is inserted into the rotating assembly, the rotating assembly and the gland assembly are axially fixed, and therefore the purpose of an integrated structure is achieved, and the transmission ring assembly is installed at the end of the rotating assembly to fix the rotating assembly and a pump shaft.

Description

Technical Field

[0001] The utility model belongs to the field of mechanical seals, and particularly relates to a mechanical seal for a spent fuel pool cooling pump. Background Art

[0002] A mechanical seal is a shaft sealing device used in rotating fluid machinery. It consists of at least a pair of end faces perpendicular to the axis of rotation. These end faces are kept in contact and relatively slide under the action of fluid pressure, the elastic force of the compensation mechanism, and the cooperation of auxiliary seals, thereby preventing fluid leakage. The spent fuel assemblies in a nuclear power plant generate a certain amount of decay heat in the spent fuel pool, and the spent fuel pool cooling pump is required to cool it to prevent the medium temperature in the pool from being too high to damage the equipment, inhibit the boiling of the medium in the spent fuel pool, and prevent the evaporation of the spent fuel pool water, resulting in the exposure and melting of the fuel assemblies and causing a large amount of radioactive substances to leak. As one of the important components of the spent fuel pool cooling pump, the key role of the mechanical seal is to effectively prevent the leakage of the medium in the pump body, avoid energy waste and possible environmental pollution. Therefore, the service life and sealing performance of the mechanical seal have a great impact on the normal operation of the pump.

[0003] The mechanical seal of the original spent fuel pool cooling pump is a non-assembled mechanical seal structure. The installation requires adjusting the working height, the process is cumbersome, the maintenance time is long, and the installation technology requirements for maintenance personnel are high. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a mechanical seal for a spent fuel pool cooling pump, which simplifies the installation process while ensuring the sealing performance and service life, and reduces the burden on maintenance personnel.

[0005] The technical solution of the utility model is as follows:

[0006] Design a mechanical seal for a spent fuel pool cooling pump, including a rotating assembly, a stationary ring, a stationary ring seal ring, a gland assembly, a positioning block, bolts, a transmission ring assembly, a pump shaft, a pump body, nuts, and studs; the end face of the dynamic ring in the rotating assembly is in contact with the end face of the stationary ring, a stationary ring seal ring is arranged between the stationary ring and the gland assembly, and is pressed against the step of the gland assembly through the stationary ring to form a sealing point; the positioning block is fastened to the gland assembly through bolts, and the end far from the bolts is inserted into the rotating assembly to realize the circumferential fixation of the rotating assembly and the gland assembly, thereby achieving the purpose of an assembled structure; the transmission ring assembly is installed at one end of the shaft sleeve in the rotating assembly to fix the rotating assembly and the pump shaft.

[0007] Preferably, the rotating assembly includes a spring assembly, a first set screw, a shaft sleeve seal ring, a shaft sleeve, a dynamic ring seal ring, and a dynamic ring; the spring assembly is installed on the shaft sleeve and contacts the shaft sleeve step, the spring assembly is concentric with the shaft sleeve and fixed by the first set screw; a dynamic ring seal ring is arranged between the spring assembly and the dynamic ring; the end face of the dynamic ring away from the spring assembly fits with the end face of the static ring away from the positioning block to form an end face seal, and the end face contact pressure is maintained under the elastic force of the spring assembly.

[0008] Preferably, the spring assembly includes a spring seat, a small spring, a push ring, a transmission pin, and a first anti-rotation pin; the spring seat and the push ring are connected by the transmission pin, the large-diameter end of the transmission pin is in clearance fit with the step hole on the spring seat, and the small-diameter end is in interference fit with the pin hole on the push ring, so as to realize the circumferential fixation of the spring seat and the push ring, the axial relative movement can be realized and they remain concentric; a small spring is arranged between the spring seat and the push ring, one end of the small spring is located in the counterbore of the spring seat and contacts the bottom of the counterbore, and the other end contacts the end face of the push ring; the small-diameter end of the push ring is inserted into the dynamic ring and presses the dynamic ring seal ring on the step inside the dynamic ring to form a sealing point; the first anti-rotation pin cooperates with the pin hole on the push ring, and the protruding end cooperates with the anti-rotation groove on the dynamic ring to realize the circumferential fixation of the push ring and the dynamic ring.

[0009] Preferably, the gland assembly includes a gland, a second anti-rotation pin, and a gland seal ring; the gland seal ring is installed in the gland seal ring groove; the second anti-rotation pin is installed in the step hole of the gland, and the protruding part cooperates with the anti-rotation groove of the static ring to realize the circumferential fixation of the static ring and the gland; the gland is processed with a flushing hole and a leakage hole, the flushing hole is used to introduce a flushing medium to flush and exchange heat with the friction pair end face of the mechanical seal, and the leakage hole is used to lead out the leakage medium to a corresponding collection container.

[0010] Preferably, the transmission ring assembly includes a transmission ring, a second set screw, and a third set screw; the transmission ring is installed at the small-diameter end of the outer diameter of the shaft sleeve, the step inside the transmission ring contacts the end face of the shaft sleeve to realize axial positioning; the second set screw is installed in the threaded hole of the transmission ring and fastened on the surface of the shaft sleeve to realize the fixation of the transmission ring and the shaft sleeve, the third set screw is installed in the threaded hole of the transmission ring, passes through the through hole on the shaft sleeve and is fastened on the pump shaft to realize the fixation of the transmission ring and the pump shaft, so as to realize the fixation of the pump shaft and the shaft sleeve.

[0011] Preferably, the mechanical seal of the spent fuel pool cooling pump is integrally installed on the pump shaft, the shaft sleeve seal ring is pressed in the seal ring groove of the shaft sleeve by the pump shaft to form a sealing point, and it is fixed on the pump body by studs and nuts, and the gland seal ring is pressed in the gland seal ring groove to form a sealing point.

[0012] The beneficial effects of the present utility model are as follows:

[0013] 1. In the connection between the spring seat and the push ring by the transmission pin, it not only plays the role of transmitting power but also limits the position of the push ring, enabling the spring to have a certain pre-compression and preventing the spring from falling out easily. The spring seat, push ring, transmission pin, and spring can be assembled into a component, making the mechanical seal assembly process simpler and more convenient.

[0014] 2. The improved assembled mechanical seal structure has the following advantages:

[0015] a. When installing, there is no need to adjust the working height of the mechanical seal. The working height of the assembled mechanical seal has been set after assembly and does not need to be adjusted anymore.

[0016] b. The shaft can be adjusted. Since the transmission ring is located outside the pump, only the set screw connecting the transmission ring and the pump shaft needs to be loosened, and the process is simple.

[0017] c. When installing, only the whole set of mechanical seal needs to be installed on the pump, and the connecting nuts on the gland and the set screws on the transmission ring are tightened. Then, loosen the bolts on the positioning block and withdraw the positioning block. The assembly process is simple and reliable.

[0018] d. The sealing end faces of the dynamic ring and the static ring always remain in contact, avoiding contamination of the sealing end faces by foreign matters or damage caused by operating errors before installation or startup.

[0019] e. It is easy to take out the mechanical seal as a whole for inspection or replacement, greatly shortening the maintenance time. Description of the Drawings

[0020] Figure 1 is the front view of a mechanical seal for a spent fuel pool cooling pump provided by the present utility model;

[0021] Figure 2 is the A - A cross-sectional view of a mechanical seal for a spent fuel pool cooling pump provided by the present utility model;

[0022] Figure 3 is the schematic structural view of the spring assembly of a mechanical seal for a spent fuel pool cooling pump provided by the present utility model;

[0023] Figure 4 is the B - B cross-sectional view of a mechanical seal for a spent fuel pool cooling pump provided by the present utility model.

[0024] In the figure: 1. Rotating assembly; 2. Stationary ring; 3. Stationary ring seal ring; 4. gland assembly; 5. positioning block; 6. bolt; 7. drive ring assembly; 8. pump shaft; 9. pump body; 10. nut; 11. spring assembly; 12. first set screw; 13. shaft sleeve seal ring; 14. shaft sleeve; 15. moving ring seal ring; 16. moving ring; 20. stud; 41. gland; 42. gland seal ring; 43. second anti-rotation pin; 44. flushing hole; 45. leakage hole; 71. second set screw; 72. drive ring; 73. third set screw; 111. spring seat; 112. small spring; 113. push ring; 114. first anti-rotation pin; 115. drive pin. Detailed implementation manners

[0025] The present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] As Figure 2 , Figure 3 , Figure 4 shown, the purpose of the present utility model is to provide a mechanical seal for a spent fuel pool cooling pump, which can ensure the sealing performance and service life while simplifying the installation process, improving the installation quality, and reducing the burden on maintenance personnel.

[0027] The technical solution of the present utility model is as follows:

[0028] A mechanical seal for a spent fuel pool cooling pump includes a rotating assembly 1, a stationary ring 2, a stationary ring seal ring 3, a gland assembly 4, a positioning block 5, a bolt 6, a drive ring assembly 7, a pump shaft 8, a pump body 9, a nut 10, and a stud 20; the rotating assembly 1 is in contact with the end face of the stationary ring 2, and a stationary ring seal ring 3 is arranged between the stationary ring 2 and the gland assembly 4, and is pressed against the step of the gland assembly 4 by the stationary ring 2 to form a sealing point; one end of the positioning block 5 is fastened to the gland assembly 4 through a bolt 6, and the end far from the bolt 6 is inserted into the shaft sleeve 14 in the rotating assembly 1 to realize the axial fixation of the rotating assembly 1 and the gland assembly 4, thereby achieving the purpose of an assembled structure; the drive ring assembly 7 is installed at the end of the rotating assembly 1 to fix the rotating assembly 1 and the pump shaft 8.

[0029] Further, the rotating assembly 1 includes a spring assembly 11, a first set screw 12, a shaft sleeve seal ring 13, a shaft sleeve 14, a moving ring seal ring 15, and a moving ring 16; the spring assembly 11 is installed on the shaft sleeve 14 and contacts the step of the shaft sleeve 14, the spring assembly 11 is concentric with the shaft sleeve 14 and is fixed by the first set screw 12; a moving ring seal ring 15 is arranged between the spring assembly 11 and the moving ring 16; the moving ring end face of the moving ring 16 far from the spring assembly 11 is attached to the stationary ring end face of the stationary ring 2 far from the positioning block 5 under the action of spring force to form end face sealing.

[0030] Further, the spring assembly 11 includes a spring seat 111, a small spring 112, a push ring 113, a first anti-rotation pin 114, and a transmission pin 115; the spring seat 111 and the push ring 113 are connected by the transmission pin 115. The large-diameter end of the transmission pin 115 has a clearance fit with the stepped hole on the spring seat 111, and the small-diameter end has an interference fit with the pin hole on the push ring 113, so as to achieve circumferential fixation of the spring seat 111 and the push ring 113, relative axial movement and concentricity retention; a small spring 112 is arranged between the spring seat 111 and the push ring 113. One end of the small spring 112 is located in the counterbore of the spring seat 111 and contacts the bottom of the counterbore, and the other end contacts the end face of the push ring 113; the small-diameter end of the push ring 113 is inserted into the moving ring 16 and presses the moving ring seal ring 15 against the step inside the moving ring 16 to form a sealing point; the first anti-rotation pin 114 is tightly fitted with the pin hole on the push ring 113, and the protruding end of the first anti-rotation pin 114 cooperates with the anti-rotation groove on the moving ring 16 to achieve circumferential fixation of the push ring 113 and the moving ring 16.

[0031] Further, the gland assembly 4 includes a gland 41, a gland seal ring 42, and a second anti-rotation pin 43; the gland seal ring 42 is installed in the seal ring groove of the gland 41; the second anti-rotation pin 43 is installed in the stepped hole of the gland 41, and the protruding part cooperates with the anti-rotation groove of the stationary ring 2 to achieve circumferential fixation of the stationary ring 2 and the gland 41; the gland 41 is machined with a flushing hole 44 and a leakage hole 45. The flushing hole 44 is used to introduce a flushing medium to flush and exchange heat with the friction pair end face of the mechanical seal, and the leakage hole 45 is used to lead the leaked medium to a collector.

[0032] Further, the transmission ring assembly 7 includes a second set screw 71, a transmission ring 72, and a third set screw 73; the transmission ring 72 is installed at the small-diameter end of the shaft sleeve 14, and the step inside the transmission ring 72 contacts the end face of the shaft sleeve 14; the second set screw 71 is installed in the threaded hole of the transmission ring 72 and fastened to the shaft sleeve 14 to achieve fixation of the transmission ring 72 and the shaft sleeve 14. The third set screw 73 is installed in the threaded hole of the transmission ring 72, passes through the through hole on the shaft sleeve 14 and is fastened to the pump shaft 8 to achieve fixation of the transmission ring 72 and the pump shaft 8, thereby achieving fixation of the pump shaft 8 and the shaft sleeve 14.

[0033] Furthermore, the mechanical seal of the spent fuel pool cooling pump is integrally installed on the pump shaft 8. The shaft sleeve seal ring 13 is pressed by the pump shaft 8 into the seal ring groove of the shaft sleeve 14 to form a sealing point, and is fixed to the pump body 9 by a stud 20 and a nut 10, and the gland seal ring 42 is pressed into the seal ring groove of the gland 41 to form a sealing point.

[0034] The above description is made for the present utility model and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present utility model, and the actual structure is not limited thereto. In short, if those of ordinary skill in the art are inspired by it and without departing from the gist of the creation of the present utility model, they design similar structural modes and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present utility model.

Claims

1. A mechanical seal for a spent fuel pool cooling pump, comprising a rotating assembly (1), a stationary ring (2), a stationary ring sealing ring (3), a gland assembly (4), a positioning block (5), a bolt (6), a transmission ring assembly (7), a pump shaft (8), a pump body (9), a nut (10), and a stud (20); the rotating assembly (1) is fitted with the end surface of the stationary ring (2); a stationary ring sealing ring (3) is arranged between the stationary ring (2) and the gland assembly (4), and is pressed against a step of the gland assembly (4) through the stationary ring (2) to form a sealing point; the positioning block (5) is fastened to the gland assembly (4) through a bolt (6), and an end away from the bolt (6) is inserted into a shaft sleeve (14) in the rotating assembly (1), so as to realize axial fixation of the rotating assembly (1) and the gland assembly (4); the transmission ring assembly (7) is installed at the end position of the rotating assembly (1) to fix the rotating assembly (1) and the pump shaft (8).

2. A spent fuel pool cooling pump mechanical seal according to claim 1, characterized in that: The rotating assembly (1) comprises a spring assembly (11), a first set screw (12), a shaft sleeve sealing ring (13), a shaft sleeve (14), a dynamic ring sealing ring (15), and a dynamic ring (16); the spring assembly (11) is mounted on one end of the step of the shaft sleeve (14), the spring assembly (11) and the shaft sleeve (14) are kept concentric and fixed by the first set screw (12); a dynamic ring sealing ring (15) is arranged between the spring assembly (11) and the dynamic ring (16); the dynamic ring end face of the dynamic ring (16) away from the spring assembly (11) is in contact with the static ring end face of the static ring (2) away from the positioning block (5), and the end faces are kept in contact under the elastic force of the spring assembly (11) to form an end face seal.

3. A spent fuel pool cooling pump mechanical seal according to claim 2, characterized in that: The spring assembly (11) comprises a spring seat (111), a small spring (112), a push ring (113), a first anti-rotation pin (114), and a transmission pin (115); the spring seat (111) and the push ring (113) are connected via the transmission pin (115); the large diameter end of the transmission pin (115) cooperates with the step hole on the spring seat (111), and the small diameter end cooperates with the pin hole on the push ring (113), so that the spring seat (111) and the push ring (113) are circumferentially fixed, axially movable relative to each other and kept concentric; the spring seat (111) and the push ring (113), one end of the small spring (112) is located in the countersunk hole of the spring seat (111) and contacts the bottom of the countersunk hole, and the other end contacts the end face of the push ring (113); the small diameter end of the push ring (113) is inserted into the movable ring (16) and presses the movable ring sealing ring (15) onto the step inside the movable ring (16) to form a sealing point; the first anti-rotation pin (114) cooperates with the pin hole on the push ring (113), and the protruding end cooperates with the anti-rotation pin groove on the movable ring (16) to achieve circumferential fixation of the push ring (113) and the movable ring (16).

4. A spent fuel pool cooling pump mechanical seal according to claim 1, characterized in that: The gland assembly (4) comprises a gland (41), a gland sealing ring (42), and a second anti-rotation pin (43); the gland sealing ring (42) is installed in the sealing ring groove of the gland (41); the second anti-rotation pin (43) is installed in the step hole of the gland (41), and the protruding portion cooperates with the anti-rotation pin groove on the back of the stationary ring (2) to achieve circumferential fixation of the stationary ring (2) and the gland (41); the gland (41) is machined with a flushing hole (44) and a leakage hole (45), the flushing hole (44) is used to introduce a flushing medium to flush the friction pair end face of the mechanical seal, and the leakage hole (45) is used to lead the leakage medium to a corresponding collection container.

5. A spent fuel pool cooling pump mechanical seal according to claim 1, characterized in that: The transmission ring assembly (7) comprises a second set screw (71), a transmission ring (72), and a third set screw (73); the transmission ring (72) is mounted on the small-diameter end of the shaft sleeve (14); the step inside the transmission ring (72) matches the end face of the shaft sleeve (14) near the end of the positioning groove; the second set screw (71) is mounted in the threaded hole of the transmission ring (72) and is fastened to the shaft sleeve (14) to achieve the fixing of the transmission ring (72) and the shaft sleeve (14); the third set screw (73) is mounted in the threaded hole of the transmission ring (72), passes through the through hole on the shaft sleeve (14) and is fastened to the pump shaft (8) to achieve the fixing of the transmission ring (72) and the pump shaft (8), thereby achieving the fixing of the pump shaft (8) and the shaft sleeve (14).

6. A spent fuel pool cooling pump mechanical seal according to claim 1, characterized in that: The pump shaft (8) presses the shaft sleeve sealing ring (13) into the sealing ring groove of the shaft sleeve (14) to form a sealing point; the stud (20) and the nut (10) fix the gland (41) on the pump body (9) and press the gland sealing ring (42) into the sealing ring groove of the gland (41) to form a sealing point.

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