Main pump dynamic pressure shaft seal test bed

Abstract

The invention provides a main pump dynamic pressure shaft seal test bench, which comprises a motor arranged on the top, a support, a cavity, a main pump rotating shaft and a shaft sleeve, the shaft sleeve is sequentially provided with a first-stage seal, a second-stage seal and a third-stage seal from bottom to top, and the first-stage seal is located on the inner side of the cavity; a groove is formed in a main pump rotating shaft, a sectioning ring is arranged on the main pump rotating shaft, a shaft sleeve is limited, the sectioning ring is divided into two symmetrical halves and clamped into a clamping groove (12), each stage of sealing comprises a rotating ring and a static ring, the rotating ring and the static ring are arranged in an adjacent mode, and a friction pair is formed between the adjacent end faces of the rotating ring and the static ring to serve as a sealing face. A spring seat is arranged on the shaft sleeve of the rotating ring of each stage of seal, a spring is arranged in the spring seat, and a belleville spring is arranged at the front end, close to the medium side, of the shaft sleeve and used for supplementing axial accumulated machining errors of the shaft sleeve. The device has extremely high reliability, stable leakage rate can be ensured during operation, and long-term reliable operation can be realized.

Description

Technical Field

[0001] The invention relates to the field of dynamic pressure shaft seals for main pumps in nuclear power plants, in particular to a main pump dynamic pressure shaft seal test bench. Background Art

[0002] The main pump is a key equipment in a nuclear power plant. The mechanical seal is one of the key components of the main pump, used to limit the leakage of reactor coolant. It is also the most easily damaged component on the main pump. Any slight operating deviation can cause abnormal leakage and even lead to an emergency shutdown of the reactor, threatening the safe production of the power plant and causing huge economic losses.

[0003] The main pump shaft seals in nuclear power plants require extremely high seal reliability, maintaining a stable leakage rate during operation and ensuring long-term reliable operation. Main pump shaft seal components must withstand one-third of the primary circuit pressure during normal operation and, under exceptional circumstances, the full primary circuit pressure. The main pump dynamic pressure shaft seal components must be highly reliable and must not loosen or break during operation or under exceptional operating conditions, ensuring component integrity until a normal shutdown. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a main pump dynamic pressure shaft seal test bench, which simulates the normal operating conditions, abnormal operating conditions, start-up and shutdown test conditions of the main pump mechanical seal to ensure the factory condition of the mechanical seal.

[0005] To achieve the above purpose, the technical solution of the present invention is as follows:

[0006] A main pump dynamic pressure shaft seal test bench includes a motor 1 on the top, a bracket 2 at the bottom, a cavity 3 fixedly connected to the bracket, a main pump rotating shaft 4 is arranged inside the cavity 3, and the main pump rotating shaft 4 is transmission-connected to the motor 1.

[0007] The main pump rotating shaft 4 is sleeved with a shaft sleeve 10, and the shaft sleeve 10 is sequentially mounted with a primary seal 7, a secondary seal 8 and a tertiary seal 9 from bottom to top, and the primary seal 7 is located inside the cavity;

[0008] A groove is dug on the main pump rotating shaft 4 to set a petal ring 11 to limit the shaft sleeve 10. The petal ring 11 is divided into two symmetrical halves and is clamped into the clamping groove 12.

[0009] Each level of sealing includes a rotating ring 52 and a stationary ring 62. The rotating ring 52 and the stationary ring 62 are arranged adjacent to each other, and a friction pair is formed between the adjacent end surfaces of the rotating ring 52 and the stationary ring 62 as a sealing surface;

[0010] A spring seat 14 is provided on the shaft sleeve of the rotating ring of each stage seal, and a spring 13 is provided in the spring seat. The spring 13 is used to compensate for the end face wear of the rotating ring 52, the movement of the main pump rotating shaft 4 or the displacement caused by the change of working conditions.

[0011] A disc spring 15 is provided at the front end of the sleeve 10 close to the medium side, for compensating for the accumulated machining error in the axial direction of the sleeve 10 .

[0012] As a preferred embodiment, the lower end of the sleeve 10 abuts against the shoulder of the main pump rotating shaft 4, and the upper end of the sleeve 10 is fixed to the main pump rotating shaft 4 through a positioning assembly, and the positioning assembly includes a petal ring 11, a pressure ring 16, a tightening screw 17 and an elastic washer 18. The petal ring 11 is clamped in the slot 12, and an annular step 19 is provided on the upper end face of the sleeve 10. The annular step 19 is coaxial with the main pump rotating shaft 4, and the pressure ring 16 is installed in the annular step 19. The tightening screw 17 passes through the petal ring 11 and is locked in the pressure ring 16. An elastic washer 18 is provided between the pressure ring 16 and the annular step 19.

[0013] As a preferred embodiment, each of the first-stage seal 7, the second-stage seal 8, and the third-stage seal 9 is provided with a rotating ring assembly and a stationary ring assembly respectively;

[0014] The rotating ring assembly includes a rotating ring seat 51 and a rotating ring 52. A rotating snap ring 53 is provided above the rotating ring. The pump shaft drives the rotating ring assembly to rotate through the shaft sleeve 10. The rotating snap ring 53 is clamped on the outer diameters of the rotating ring seat 51 and the rotating ring 52. The rotating snap ring 53 connects the rotating ring seat 51 and the rotating ring 52 into a whole.

[0015] The stationary ring assembly includes a stationary ring seat 61 and a stationary ring 62. A stationary snap ring 63 is provided above the stationary ring. The stationary snap ring 63 is clamped on the outer diameters of the stationary ring seat 61 and the stationary ring 62. The stationary ring seat 61 and the stationary ring 62 are connected as a whole through the stationary snap ring 63.

[0016] As a preferred embodiment, the motor 1 drives the main pump rotating shaft 4 through the coupling 21 , and the main pump rotating shaft 4 is ensured to be concentric with the cavity through the bearing 20 .

[0017] As a preferred embodiment, a rotor bearing 22 is provided between the upper end of the main pump rotating shaft 4 and the cavity 3 .

[0018] The beneficial effects of the present invention are:

[0019] A spring seat 13 is provided on the sleeve of the rotating ring of each stage of sealing, and a spring 14 is provided in the spring seat. The spring 14 is used to compensate for the wear of the end face of the rotating ring, the movement of the main pump rotating shaft 4, or the displacement caused by the change of the working condition. A butterfly spring 15 is provided at the front end of the sleeve 10 close to the medium side to supplement the axial cumulative processing error of the sleeve 10. The seal of the present invention has extremely high reliability, can ensure a stable leakage rate during operation, and can operate reliably for a long time. The main pump shaft seal components can withstand one-third of the pressure of a circuit when working normally, and can withstand the full pressure of a circuit under special circumstances. During operation or special working conditions, no loosening, rupture or other damage will occur, and the integrity of the parts can be guaranteed until normal shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the front view of the present invention.

[0021] Figure 2 It is the main view of the present invention for showing the rotating ring, the stationary ring, and the seals at various levels.

[0022] 1-motor, 2-bracket, 3-cavity, 4-main pump rotating shaft, 51-rotating ring seat, 52-rotating ring, 53-rotating retaining ring, 61-stationary ring seat, 62-stationary ring, 63-stationary retaining ring, 7-primary seal, 8-secondary seal, 9-tertiary seal, 10-sleeve, 11-petal ring, 12-slot, 13-spring, 14-spring seat, 15-butterfly spring, 16-pressure ring, 17 tightening screw, 18-elastic washer, 19-annular step, 20-bearing, 21-coupling, 22-rotor bearing. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] like Figure 1 As shown, this embodiment provides a main pump dynamic pressure shaft seal test bench, including a motor 1 on the top, a bracket 2 at the bottom, a cavity 3 fixedly connected to the upper part of the bracket, a main pump rotating shaft 4 is provided inside the cavity 3, and the main pump rotating shaft 4 is transmission-connected to the motor 1.

[0025] The main pump rotating shaft 4 is sleeved with a shaft sleeve 10, and the shaft sleeve 10 is sequentially mounted with a primary seal 7, a secondary seal 8 and a tertiary seal 9 from bottom to top, and the primary seal 7 is located inside the cavity;

[0026] A groove is dug on the main pump rotating shaft 4 to set a petal ring 11 to limit the shaft sleeve 10. The petal ring 11 is divided into two symmetrical halves and is clamped into the clamping groove 12.

[0027] Each level of sealing includes a rotating ring 52 and a stationary ring 62. The rotating ring 52 and the stationary ring 62 are arranged adjacent to each other, and a friction pair is formed between the adjacent end surfaces of the rotating ring 52 and the stationary ring 62 as a sealing surface;

[0028] A spring seat 14 is provided on the shaft sleeve of the rotating ring of each stage seal, and a spring 13 is provided in the spring seat. The spring 13 is used to compensate for the end face wear of the rotating ring 52, the movement of the main pump rotating shaft 4 or the displacement caused by the change of working conditions.

[0029] A disc spring 15 is provided at the front end of the sleeve 10 close to the medium side, for compensating for the accumulated machining error in the axial direction of the sleeve 10 .

[0030] The lower end of the sleeve 10 abuts against the shoulder of the main pump rotating shaft 4, and the upper end of the sleeve 10 is fixed to the main pump rotating shaft 4 through a positioning assembly. The positioning assembly includes a petal ring 11, a pressure ring 16, a tightening screw 17 and an elastic washer 18. The petal ring 11 is clamped in the slot 12. An annular step 19 is provided on the upper end surface of the sleeve 10. The annular step 19 is coaxial with the main pump rotating shaft 4. The pressure ring 16 is installed in the annular step 19. The tightening screw 17 passes through the petal ring 11 and is locked in the pressure ring 16. An elastic washer 18 is provided between the pressure ring 16 and the annular step 19.

[0031] Each of the primary seal 7, secondary seal 8, and tertiary seal 9 is provided with a rotating ring assembly and a stationary ring assembly respectively;

[0032] like Figure 2 As shown, the rotating ring assembly includes a rotating ring seat 51 and a rotating ring 52. A rotating snap ring 53 is provided above the rotating ring. The pump shaft drives the rotating ring assembly to rotate through the shaft sleeve 10. The rotating snap ring 53 is clamped on the outer diameter of the rotating ring seat 51 and the rotating ring 52. The rotating ring seat 51 and the rotating ring 52 are connected as a whole through the rotating snap ring 53.

[0033] The stationary ring assembly includes a stationary ring seat 61 and a stationary ring 62. A stationary snap ring 63 is provided above the stationary ring. The stationary snap ring 63 is clamped on the outer diameters of the stationary ring seat 61 and the stationary ring 62. The stationary ring seat 61 and the stationary ring 62 are connected as a whole through the stationary snap ring 63.

[0034] The motor 1 drives the main pump rotating shaft 4 through the coupling 21 , and the main pump rotating shaft 4 is ensured to be concentric with the cavity through the bearing 20 .

[0035] A rotor bearing 22 is provided between the upper end of the main pump rotating shaft 4 and the cavity 3 .

[0036] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A main pump dynamic pressure shaft seal test bench, characterized by: The invention comprises a motor (1) placed on the top, a bracket (2) at the bottom, a cavity (3) fixedly connected to the bracket, a main pump rotating shaft (4) arranged inside the cavity (3), and the main pump rotating shaft (4) is connected to the motor (1) in a transmission manner. The main pump rotating shaft (4) is sleeved with a shaft sleeve (10), and the shaft sleeve (10) is sequentially mounted with a primary seal (7), a secondary seal (8) and a tertiary seal (9) from bottom to top, wherein the primary seal (7) is located inside the cavity; A split ring (11) is provided on the main pump rotating shaft (4) to limit the shaft sleeve (10). The split ring (11) is divided into two symmetrical halves and is inserted into the slot (12). Each level of sealing includes a rotating ring (52) and a stationary ring (62), the rotating ring (52) and the stationary ring (62) are arranged adjacent to each other, and a friction pair is formed between adjacent end faces of the rotating ring (52) and the stationary ring (62) as a sealing surface; A spring seat (14) is provided on the shaft sleeve of the rotating ring of each stage seal, and a spring (13) is provided in the spring seat. The spring (13) is used to compensate for the end face wear of the rotating ring (52), the movement of the main pump rotating shaft (4) or the displacement caused by the change of working conditions. A butterfly spring (15) is provided at the front end of the shaft sleeve (10) close to the medium side, for compensating for the accumulated machining error of the shaft sleeve (10) in the axial direction.

2. A main pump dynamic pressure shaft seal test bench according to claim 1, characterized in that: The lower end of the shaft sleeve (10) abuts against the shoulder of the main pump rotating shaft (4), and the upper end of the shaft sleeve (10) is fixed to the main pump rotating shaft (4) through a positioning assembly, and the positioning assembly includes a petal ring (11), a pressure ring (16), a tightening screw (17) and an elastic washer (18). The petal ring (11) is clamped in the clamping groove (12), and an annular step (19) is provided on the upper end surface of the shaft sleeve (10). The annular step (19) is coaxial with the main pump rotating shaft (4), and the pressure ring (16) is installed in the annular step (19). The tightening screw (17) passes through the petal ring (11) and is locked in the pressure ring (16). An elastic washer (18) is provided between the pressure ring (16) and the annular step (19).

3. The main pump dynamic pressure shaft seal test bench according to claim 1, characterized in that: Each of the first-stage seal (7), the second-stage seal (8), and the third-stage seal (9) is provided with a rotating ring assembly and a stationary ring assembly respectively; The rotating ring assembly comprises a rotating ring seat (51) and a rotating ring (52). A rotating snap ring (53) is provided above the rotating ring. The pump shaft drives the rotating ring assembly to rotate through the shaft sleeve (10). The rotating snap ring (53) is clamped on the outer diameters of the rotating ring seat (51) and the rotating ring (52). The rotating ring seat (51) and the rotating ring (52) are connected as a whole through the rotating snap ring (53). The stationary ring assembly comprises a stationary ring seat (61) and a stationary ring (62). A stationary snap ring (63) is provided above the stationary ring. The stationary snap ring (63) is snapped onto the outer diameters of the stationary ring seat (61) and the stationary ring (62). The stationary ring seat (61) and the stationary ring (62) are connected as a whole via the stationary snap ring (63).

4. The main pump dynamic pressure shaft seal test bench according to claim 1, characterized in that: The motor (1) drives the main pump rotating shaft (4) through the coupling (21), and the main pump rotating shaft (4) is ensured to be concentric with the cavity through the bearing (20).

5. The main pump dynamic pressure shaft seal test bench according to claim 1, characterized in that: A rotor bearing (22) is provided between the upper end of the main pump rotating shaft (4) and the cavity (3).

Images