Mechanical sealing structure for high-pressure pump of nuclear power station

Abstract

The invention provides a mechanical sealing structure for a high-pressure pump of a nuclear power station, which comprises a first-stage spring seat, the first-stage spring seat is fixedly mounted on a shaft sleeve, a first-stage moving ring is arranged on the inner side of the first-stage spring seat, a first-stage push ring is arranged on the left side of the first-stage moving ring, a first-stage static ring is arranged on the right side of the first-stage moving ring, and a first anti-rotating pin is arranged on the first-stage static ring. The high-pressure working condition of the shutdown cooling SDC pump is met, the high-pressure working condition is adapted, deformation and damage of parts are not prone to being caused, and the requirement for the sealing leakage rate is met.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical seals for high-pressure pumps in nuclear power plants, and in particular to a mechanical seal structure for high-pressure pumps in nuclear power plants. Background Art

[0002] Nuclear-grade pumps build pressure boundaries and perform safety functions during power plant operation, and are important equipment for transporting media in key systems. Nuclear-grade pump shutdown cooling SDC pumps are important equipment in nuclear power plants. The mechanical seal structure is one of the key components of the pump and is also the most easily damaged component on the pump. The mechanical seal structure components of the pump should be able to meet the requirements of reliable operation under normal operating conditions, abnormal operating conditions, and accident operating conditions, to avoid pump shutdown due to abnormal leakage, threatening the safe production of the power plant, and causing huge economic losses and safety hazards.

[0003] The shutdown cooling SDC pump requires extremely high reliability of the seal. Under normal working conditions, it can withstand two pressure values ​​and temperature values. The pressure value varies greatly. One working condition is 0.62MPa of the seal chamber pressure, and the other working condition is 10.48MPa of the seal chamber pressure. Under emergency conditions, the seal chamber pressure value can reach 12.55MPa. The mechanical seal structure withstands high pressure. Due to the high pressure, the various parts of the mechanical seal structure will also withstand greater extrusion and torsional stress, which can easily cause damage to the parts, thereby impairing the performance of the mechanical seal.

[0004] At present, conventional mechanical seal structures cannot meet the high-pressure working conditions of shutdown cooling SDC pumps. High-pressure working conditions can easily cause parts to deform and damage, resulting in seal leakage exceeding the use requirements. Summary of the invention

[0005] The purpose of the present invention is to provide a mechanical seal structure for a high-pressure pump in a nuclear power plant, which solves the problem that high-pressure working conditions of the existing seal structure easily cause deformation, damage of parts and excessive seal leakage.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A mechanical seal structure for a high-pressure pump in a nuclear power plant comprises a primary spring seat, which is fixedly mounted on a shaft sleeve, a primary dynamic ring is arranged on the inner side of the primary spring seat, a primary push ring is arranged on the left side of the primary dynamic ring, and a primary static ring is arranged on the right side, and a first anti-rotation pin is arranged on the primary static ring.

[0008] As an implementable manner, a keyway is provided on the primary spring seat, and the first key passes through the keyway so that the primary spring seat is clamped on the shaft sleeve.

[0009] As an practicable manner, a first set screw passes through the primary spring seat to install the primary spring seat onto the shaft sleeve.

[0010] As an implementable manner, a shift fork slot is provided on the primary spring seat, the primary spring seat shift fork is inserted into the outer circular groove of the primary moving ring, and the primary spring seat drives the primary moving ring to rotate.

[0011] As an implementable manner, a primary push ring is provided between the primary spring seat and the primary moving ring.

[0012] As an implementable manner, a sealing groove is opened on the inner side of the primary dynamic ring, and the primary dynamic ring O-ring is installed in the sealing groove.

[0013] As an implementable manner, the first clamping ring is arranged outside the primary dynamic ring and abuts against the primary spring seat.

[0014] As an practicable manner, the material used for the primary stationary ring is nickel-based hard alloy.

[0015] As an practicable manner, the material used for the primary dynamic ring is impregnated graphite.

[0016] As an practicable manner, two sealing structures are arranged on the shaft sleeve, and the two sealing structures form a high-pressure series sealing structure; the first sealing structure includes the primary spring seat, the primary dynamic ring, the primary push ring, the primary static ring, and the first anti-rotation pin; the second sealing structure includes the secondary spring seat, the secondary dynamic ring, the secondary push ring, the secondary static ring, and the second anti-rotation pin.

[0017] Compared with the prior art, the mechanical seal structure for a nuclear power plant high-pressure pump provided by the present invention has the following beneficial effects:

[0018] The present invention meets the high-pressure working conditions of the shutdown cooling SDC pump, is adaptable to high-pressure working conditions, is not prone to deformation and damage of parts, and meets the requirements for sealing leakage.

[0019] The parts of the present invention are stable and reliable, can withstand high-pressure media, and have small sealing leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the mechanical seal structure for a high-pressure pump in a nuclear power plant provided by the present invention.

[0022] Description of reference numerals:

[0023] 1-first key; 2-first set screw; 3-first spring; 4-first push ring; 5-first moving ring O-ring; 6-first spring seat; 7-first moving ring; 8-first clamping ring; 9-first static ring; 10-first static ring O-ring; 11-first anti-rotation pin; 12-second spring seat; 13-second set screw; 14-second key; 15-second spring; 16-second push ring; 17-second moving ring O-ring; 18-second moving ring; 19-second clamping ring; 20-second static ring; 21-second static ring O-ring; 22-second anti-rotation pin. DETAILED DESCRIPTION

[0024] The following is further explained in detail through specific implementation methods.

[0025] like Figure 1 As shown, the present invention provides a mechanical seal structure for a high-pressure pump in a nuclear power plant, comprising a rotating part structure and a stationary part structure.

[0026] The rotating part structure includes a first key 1, a first set screw 2, a first spring 3, a primary push ring 4, a primary moving ring O-ring 5, a primary spring seat 6, a primary moving ring 7, and a first clamping ring 8.

[0027] A keyway is provided on the primary spring seat 6, through which the first key 1 is clamped on the shaft sleeve, and the first set screw 2 passes through the primary spring seat 6 to install the primary spring seat 6 on the shaft sleeve. The primary spring seat 6 rotates with the shaft sleeve under the transmission of the first key 1 and the first set screw 2.

[0028] The primary moving ring 7 is installed to the inner side of the primary spring seat 6. A shift fork slot is provided on the primary spring seat 6. The shift fork of the primary spring seat 6 is inserted into the outer circular groove of the primary moving ring 7. The primary spring seat 6 drives the primary moving ring 7 to rotate.

[0029] The primary push ring 4 is arranged on the left side of the primary dynamic ring 7, and plays the role of uniformly applying the spring force to the dynamic ring. The primary push ring 4 is arranged between the primary spring seat 6 and the primary dynamic ring 7.

[0030] A sealing groove is provided on the inner side of the primary moving ring 7, into which the primary moving ring O-ring 5 is installed. The primary moving ring O-ring 5 (moving ring sealing ring) is located between the inner hole of the primary moving ring 7 and the outer circle of the shaft sleeve to form a sealing point to prevent leakage.

[0031] The first clamping ring 8 is arranged on the outside of the primary movable ring 7 and abuts against the primary spring seat 6. The function of the first clamping ring 8 is to pre-assemble and pre-compress the primary spring seat 6, the first spring 3, the primary push ring 4, and the primary movable ring 7, so that the entire rotating assembly is easy to assemble and transport.

[0032] The first spring 3 is installed on the primary spring seat 6 , and its function is to provide elastic force for the primary dynamic ring 7 , overcome the influence of micro-motion on the primary dynamic ring 7 , and ensure the fit between the primary dynamic ring 7 and the primary static ring 9 .

[0033] In the rotating part structure, because the seal needs to withstand higher pressure, each part of the rotating part is considered to have sufficient strength to withstand the extrusion and torsional stress caused by high pressure. The first set screw 2 is provided on the first-level spring seat 6, and a keyway is also provided. The transmission design of the first-level spring seat 6 is a fork structure. The first-level dynamic ring 7 has a correspondingly increased wall thickness, and the fork slot corresponding to the first-level spring seat 6 is also provided.

[0034] The primary spring seat 6 is connected to the sleeve through the first set screw 2, and a key is also provided between the sleeve and the primary spring seat 6. The first set screw 2 and the flat key transmit torque at the same time to prevent the first set screw 2 from slipping due to excessive axial force. The primary spring seat 6 and the moving ring are driven by a shift fork, and the contact area between the shift fork and the moving ring is larger. At the same time, compared with other transmission methods (such as pins and lugs), the shift fork has higher strength, better force resistance, and is not easy to slip.

[0035] The static part structure includes a primary static ring 9, a primary static ring O-ring 10, and a first anti-rotation pin 11. The primary static ring 9 is kept relatively static with the gland through the first anti-rotation pin 11, and the primary static ring O-ring 10 prevents the sealing liquid from leaking between the static ring and the gland. The primary static ring 9 is installed on the right side of the primary dynamic ring 7, the primary static ring O-ring 10 is installed on the outside of the primary static ring 9, and the first anti-rotation pin 11 is inserted into the primary static ring 9.

[0036] The first-level static ring 9 adopts a flat ring structure, which can better ensure the wall thickness of the static ring, thereby ensuring the strength of the ring. At the same time, the first-level static ring 9 is subjected to the entire force on the gland, avoiding the force acting on the flexible auxiliary sealing ring, which is more suitable for high-pressure occasions.

[0037] The material used for the primary static ring 9 is nickel-based hard alloy. The material used for the primary dynamic ring 7 is impregnated graphite.

[0038] Because the seal needs to withstand higher pressure, the mechanical seal structure of the nuclear power plant's high-pressure pump is designed as a high-pressure series seal structure. The first-level and second-level seals use the same above-mentioned seal structure. The first-level and second-level seals only have different installation dimensions (such as radial dimensions) (to facilitate the overall installation of the seal), but the structures of each part are similar and the principles are the same.

[0039] The secondary sealing structure includes a rotating part structure and a stationary part structure, wherein the rotating part includes a second key 14, a second set screw 13, a second spring 15, a secondary push ring 16, a secondary dynamic ring O-ring 17, a secondary spring seat 12, a secondary dynamic ring 18, and a second clamping ring 19. The stationary part structure includes a secondary static ring 20, a secondary static ring O-ring 21, and a second anti-rotation pin 22. The connection relationship between the rotating part structure and the stationary part structure is the same as that of the above-mentioned primary sealing structure.

[0040] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A mechanical seal structure for a high-pressure pump in a nuclear power plant, characterized in that: The invention comprises a primary spring seat (6), wherein the primary spring seat (6) is fixedly mounted on a shaft sleeve, a primary dynamic ring (7) is arranged on the inner side of the primary spring seat (6), a primary push ring (4) is arranged on the left side of the primary dynamic ring (7), and a primary static ring (9) is arranged on the right side, and a first anti-rotation pin (11) is arranged on the primary static ring (9).

2. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: The primary spring seat (6) is provided with a keyway, and the first key (1) passes through the keyway so that the primary spring seat (6) is clamped on the shaft sleeve.

3. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: The first set screw (2) passes through the primary spring seat (6) to mount the primary spring seat (6) onto the shaft sleeve.

4. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: The first-stage spring seat (6) is provided with a shift fork slot, the shift fork of the first-stage spring seat (6) is inserted into the outer circular groove of the first-stage moving ring (7), and the first-stage spring seat (6) drives the first-stage moving ring (7) to rotate.

5. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: A primary push ring (4) is provided between the primary spring seat (6) and the primary moving ring (7).

6. The mechanical seal structure for a nuclear power plant high pressure pump according to claim 1, characterized in that: A sealing groove is provided on the inner side of the primary dynamic ring (7), and the primary dynamic ring O-ring (5) is installed in the sealing groove.

7. The mechanical seal structure for a nuclear power plant high pressure pump according to claim 1, characterized in that: The first clamping ring (8) is arranged outside the primary movable ring (7) and abuts against the primary spring seat (6).

8. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: The material used for the primary stationary ring (9) is nickel-based hard alloy.

9. The mechanical seal structure for a nuclear power plant high-pressure pump according to claim 1, characterized in that: The material used for the primary moving ring (7) is impregnated graphite.

10. The mechanical seal structure for a nuclear power plant high pressure pump according to claim 1, characterized in that: Two sealing structures are arranged on the shaft sleeve, and the two sealing structures form a high-pressure series sealing structure; the first sealing structure comprises the primary spring seat (6), the primary dynamic ring (7), the primary push ring (4), the primary static ring (9), and the first anti-rotation pin (11); the second sealing structure comprises the secondary spring seat (12), the secondary dynamic ring (18), the secondary push ring (16), the secondary static ring (20), and the second anti-rotation pin (22).

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