A shaft seal structure for steam turbines
By incorporating staggered tooth structures and air passages in the labyrinth seal structure of the steam turbine, and utilizing the principle of gas counteraction, the problem of gas leakage in the steam turbine is solved, achieving a higher sealing effect and equipment reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HWASU
- Filing Date
- 2025-09-18
- Publication Date
- 2026-07-03
AI Technical Summary
When using labyrinth seals in existing steam turbines, there is a problem of large media leakage and difficulty in effectively suppressing gas leakage.
A novel labyrinth sealing structure is adopted, which forms air passages and through holes by setting staggered tooth structures on rotating and fixed parts. Gas is blown into the air passages under the guidance of the arc surface, so that the gas counteracts each other, thereby suppressing leakage.
This effectively reduces gas leakage and improves the airtightness of the steam turbine and the reliability of equipment operation.
Smart Images
Figure CN224452862U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of steam turbine sealing technology, and in particular to a shaft seal structure for steam turbines. Background Technology
[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam power unit. High-temperature, high-pressure steam passes through a fixed nozzle, becomes an accelerated airflow, and is then injected onto the blades, causing the rotor equipped with a row of blades to rotate and perform work.
[0003] A certain clearance (typically 0.35-0.80 mm) must be maintained between the turbine rotor and the cylinder to allow for thermal expansion and vibration during high-speed rotation, preventing direct contact between moving and stationary parts that could lead to frictional damage. If contact seals (such as mechanical seals) are used, high-speed friction will generate a large amount of heat, potentially causing shaft bending or sealing surface erosion. Therefore, turbines require labyrinth seals for sealing. The core principle of labyrinth seals is to reduce media leakage through the throttling effect of multi-stage tortuous gaps and expansion cavities. This invention provides a novel labyrinth seal structure. Utility Model Content
[0004] This utility model discloses a shaft seal structure for a steam turbine, including a rotating component fixed on a rotating shaft and a fixed component fixed on the steam turbine casing. Several sets of sealing structures are provided on the rotating component and the fixed component. The rotating component and the fixed component work together to perform shaft sealing.
[0005] The sealing structure includes a first tooth and a third tooth fixed to a rotating component, and a second tooth and a fourth tooth fixed to a fixed component. The first, second, third, and fourth teeth are arranged sequentially. A first conical surface is provided on one side of the end of the second tooth, and a second conical surface is provided on the upper end of the third tooth. An air passage is formed between the first and second conical surfaces. An inclined through-hole is provided through the upper part of the second tooth, and an arc surface is provided on one side of the upper part of the fourth tooth, with the lower tangent of the arc surface facing the air passage. Gas passing through the through-hole is guided by the arc surface and blown into the air passage. The gaps formed by the staggered arrangement of the first, second, third, and fourth teeth meet the requirements of turbine operation. Gas passes through the gaps and through-holes. When gas passes through the air passage, the gas passing through the through-hole is guided by the arc surface and is refluxed back into the air passage. The gas in the air passage and the refluxed gas collide, thereby suppressing gas leakage and improving the airtightness of the turbine equipment.
[0006] Preferably, a collar is fixedly connected to the upper side of the first tooth, and the collar is located below the fourth tooth in the left-side sealing structure. This arrangement increases the complexity of the labyrinth, thereby improving airtightness.
[0007] Preferably, the rotating component includes a mounting sleeve, and both the first tooth and the third tooth are fixedly connected to the mounting sleeve. That is, the rotating component is sleeved on the rotating shaft. Furthermore, the first tooth and the third tooth can be machined directly on the rotating shaft.
[0008] Preferably, one end of the mounting sleeve is fixedly connected to a flange, and the flange has several countersunk holes. It is then fixedly connected to the rotating shaft using bolts or other connecting components.
[0009] Preferably, a sealing groove is provided on the inner side of one end of the flange to achieve a seal between the rotating component and the rotating shaft.
[0010] Preferably, the fastener includes a connecting sleeve, with the second and fourth teeth fixedly connected to the inner wall of the connecting sleeve, and a T-shaped connecting portion provided on the outer wall of the connecting sleeve. The T-shaped connecting portion is used to fit into the outer casing of the steam turbine.
[0011] The beneficial effects of this utility model are as follows: It is provided with an air passage and a through hole. The gas passing through the through hole is guided by the arc surface and blown into the air passage. The gas passing through the air passage and the guided gas collide, thereby suppressing the leakage of gas and thus achieving a seal. Attached Figure Description
[0012] Figure 1 This is a partial three-dimensional structural schematic diagram of the present invention;
[0013] Figure 2 This is a three-dimensional schematic diagram of the rotating component of this utility model;
[0014] Figure 3 This is a three-dimensional schematic diagram of the fastener of this utility model;
[0015] Figure 4 This is a schematic diagram of the sealing joint of this utility model.
[0016] List of reference numerals in the attached diagram:
[0017] 1. Rotating component; 2. Fixed component;
[0018] 11. Flange; 12. Countersunk hole; 13. Sealing groove; 14. Mounting sleeve; 15. Collar; 16. First tooth; 17. Third tooth; 18. First conical surface; 21. T-shaped connection; 22. Connecting sleeve; 23. Second tooth; 24. Second conical surface; 25. Fourth tooth; 26. Arc surface; 27. Through hole. Detailed Implementation
[0019] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to the directions in the accompanying drawings, and the terms "inner" and "outer" refer to the directions toward or away from the geometric center of a specific component, respectively.
[0020] like Figures 1 to 4 As shown, a shaft sealing structure for a steam turbine includes a rotating component 1 fixed on a rotating shaft and a fixed component 2 fixed on a steam turbine casing. Several sets of sealing structures are provided on the rotating component 1 and the fixed component 2 to achieve the airtightness of the steam turbine.
[0021] The sealing structure includes a first tooth 16 and a third tooth 17 fixed on the rotating part 1, and a second tooth 23 and a fourth tooth 25 fixed on the fixing part 2. The first tooth 16, the second tooth 23, the third tooth 17 and the fourth tooth 25 are arranged in sequence, that is, the gas passes through the gap formed between the first tooth 16, the second tooth 23, the third tooth 17 and the fourth tooth 25. A first conical surface 24 is provided on one side of the end of the second tooth 23, and a second conical surface 18 is provided on the upper end of the third tooth 17. An air passage is formed between the first conical surface 24 and the second conical surface 18, and the gas passes through the air passage. An inclined through hole 27 is provided through the upper part of the second tooth 23, and an arc surface 26 is provided on one side of the upper part of the fourth tooth 25. The lower tangent direction of the arc surface 26 faces the air passage. The gas passing through the through hole 27 is blown into the air passage under the guidance of the arc surface 26, that is, the gas passing through the through hole 27 and the gas passing through the air passage are opposed to each other, thereby limiting the leakage of gas and achieving the sealing effect.
[0022] A collar 15 is fixedly connected to one side of the upper part of the first tooth 16. The collar 15 is located below the fourth tooth 25 in the left sealing structure. During the sealing process, gas passes between the fourth tooth 25 and the spring 15, and a cavity is formed inside the collar 15. This cavity increases the complexity of the labyrinth seal, thereby improving its sealing ability to a certain extent.
[0023] The rotating component 1 includes a mounting sleeve 14, which is fitted onto the turbine shaft, and the first tooth 16 and the third tooth 17 are both fixedly connected to the mounting sleeve 14. Furthermore, the first tooth 15 and the third tooth 17 can be directly machined onto the shaft.
[0024] One end of the mounting sleeve 14 is fixedly connected to a flange 11, which has several countersunk holes 12. The mounting sleeve 14 is fixedly connected to the rotating shaft by bolts or other connecting parts inserted into the countersunk holes 12.
[0025] A sealing groove 13 is provided on the inner side of one end of the flange 11. A sealing element is provided in the sealing groove 13 to achieve a seal between the rotating part 1 and the rotating shaft.
[0026] The fastener 2 includes a connecting sleeve 22, with a second tooth 23 and a fourth tooth 25 fixedly connected to the inner wall of the connecting sleeve 22. The outer wall of the connecting sleeve 22 is provided with a T-shaped connecting portion 21. It is fixedly connected to the outer casing of the steam turbine through the T-shaped connecting portion 21.
[0027] The technical means disclosed in this utility model are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.
Claims
1. A shaft seal structure for a steam turbine, characterized in that, It includes a rotating component (1) fixed on a rotating shaft and a fixed component (2) fixed on a turbine casing, wherein the rotating component (1) and the fixed component (2) are provided with several sets of sealing structures; The sealing structure includes a first tooth (16) and a third tooth (17) fixed on the rotating part (1), and a second tooth (23) and a fourth tooth (25) fixed on the fixing part (2). The first tooth (16), the second tooth (23), the third tooth (17) and the fourth tooth (25) are arranged in sequence. A first conical surface (24) is provided on one side of the end of the second tooth (23). A second conical surface (18) is provided on the upper end of the third tooth (17). An air passage is formed between the first conical surface (24) and the second conical surface (18). An inclined through hole (27) is provided through the upper part of the second tooth (23). An arc surface (26) is provided on one side of the upper part of the fourth tooth (25). The lower tangent of the arc surface (26) faces the air passage, so that the gas passing through the through hole (27) is blown into the air passage under the guidance of the arc surface (26).
2. A shaft seal structure for a steam turbine according to claim 1, characterized in that: A collar (15) is fixedly connected to the upper side of the first tooth (16), and the collar (15) is located below the fourth tooth (25) in the left sealing structure.
3. A shaft seal structure for a steam turbine according to claim 1, characterized in that: The rotating component (1) includes a mounting sleeve (14), and the first tooth (16) and the third tooth (17) are both fixedly connected to the mounting sleeve (14).
4. A shaft seal structure for a steam turbine according to claim 3, characterized in that: One end of the mounting sleeve (14) is fixedly connected to a flange (11), and the flange (11) is provided with several countersunk holes (12).
5. A shaft seal structure for a steam turbine according to claim 4, characterized in that: A sealing groove (13) is provided on the inner side of one end of the flange (11).
6. A shaft seal structure for a steam turbine according to claim 1, characterized by: The fastener (2) includes a connecting sleeve (22), the second tooth (23) and the fourth tooth (25) are fixedly connected to the inner wall of the connecting sleeve (22), and the outer wall of the connecting sleeve (22) is provided with a T-shaped connecting part (21).