Shaft end seal device for a steam turbine

Abstract

The utility model relates to turbine equipment technical field, concretely relates to a turbine for turbine shaft end sealing device, including turbine body, the middle part of turbine body is provided with rotor shaft, both ends of rotor shaft all are provided with bearing box, two bearing boxes and turbine body all are provided with sealing assembly between, sealing assembly includes sealing shell, the middle part of sealing shell is connected with high temperature steam air inlet pipe, sealing shell is close to bearing box one end and is provided with low pressure nitrogen air inlet pipe, through the double sealing effect of nitrogen and original steam, steam leakage is greatly reduced, turbine thermal efficiency and operation safety are improved, and simple structure, the transformation cost is low, and the lubricating oil oil water stratification problem that solved after the transformation of steam external leakage leads to, the bearing bush temperature and vibration value all obviously reduce.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine equipment technology, specifically to a shaft end sealing device for a turbine steam turbine. Background Technology

[0002] like Figure 1 As shown, medium-pressure steam from the thermal power boiler enters the turbine through the turbine inlet electric boundary valve, quick-closing valve, and speed regulating valve to complete the conversion process from thermal energy to kinetic energy. After doing work, it is discharged into the main condenser.

[0003] The turbine shaft end uses a labyrinth seal, and the sealing steam pressure is controlled by a pressure regulating valve. There is a gap between the turbine shaft and the turbine body. High-temperature, high-pressure steam inside the shaft end easily leaks through this gap, causing energy loss and reducing turbine thermal efficiency. Currently, superheated steam is introduced through a shaft seal regulating valve to the high-pressure and low-pressure shaft end seals for sealing. Most of the sealing steam enters the turbine along the shaft end seal comb teeth, while a small amount leaks outwards after pressure reduction along the shaft seal and shaft end. However, after long-term operation, the sealing gap increases due to wear, and the sealing effect gradually decreases. Steam leaks outwards along the shaft end gap, leading to overheating and wear of the shaft end seals. During turbine operation, the lubricating oil has repeatedly experienced oil-water separation. Investigation revealed that steam leakage from the turbine shaft seal leaked along the shaft side into the bearing housing, indicating poor lubricating oil quality. The unit's bearing temperature and vibration values ​​fluctuated, requiring regular filtration and water removal of the lubricating oil. Water in lubricating oil not only affects equipment lubrication and control systems, but also causes steam leakage, which can lead to high-temperature heating of the lubricating oil in the bearing housing and carbon buildup at the journal. Over time, this can cause increased vibration and unnecessary equipment shutdowns. Utility Model Content

[0004] To address the aforementioned issues, this utility model provides a shaft end sealing device for turbines. Through the dual sealing effect of nitrogen and the original steam, it significantly reduces steam leakage, improves turbine thermal efficiency and operational safety, and features a simple structure and low modification cost. Furthermore, the modification solves the problem of lubricating oil-water separation caused by steam leakage, and significantly reduces bearing temperature and vibration.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a shaft end sealing device for a turbine, comprising a turbine body, a rotor shaft disposed in the middle of the turbine body, bearing housings disposed at both ends of the rotor shaft, a sealing assembly disposed between the two bearing housings and the turbine body, the sealing assembly comprising a sealing housing, a high-temperature steam inlet pipe connected to the middle of the sealing housing, and a low-pressure nitrogen inlet pipe disposed at the end of the sealing housing near the bearing housing.

[0006] As a further improvement to the above technical solution:

[0007] The sealing housing includes an outer shell and an inner shell, and there are also staggered sealing comb teeth between the outer shell and the inner shell.

[0008] One end of the high-temperature steam inlet pipe is equipped with a high-temperature steam delivery pipe, and the other end extends to the inside of the sealed housing.

[0009] The high-temperature steam conveying pipe is equipped with a regulating valve, and the inlet pressure of the high-temperature steam inlet pipe is greater than 3MPa and the inlet temperature is greater than 350℃.

[0010] One end of the low-pressure nitrogen inlet pipe is equipped with a low-pressure nitrogen delivery pipe, and the other end extends to the middle of the sealed housing.

[0011] The diameter of the low-pressure nitrogen inlet pipe is 5-8 mm, and the inlet pressure is less than 50 kPa.

[0012] The two sealing components are mirror-image distributed.

[0013] The beneficial effects of this utility model embodiment are as follows: The turbine shaft end sealing device includes a turbine body, a rotor shaft is provided in the middle of the turbine body, bearing housings are provided at both ends of the rotor shaft, and a sealing assembly is provided between the two bearing housings and the turbine body. The sealing assembly includes a sealing shell, a high-temperature steam inlet pipe is connected to the middle of the sealing shell, and a low-pressure nitrogen inlet pipe is provided at the end of the sealing shell near the bearing housing. Through the double sealing effect of nitrogen and the original steam, the steam leakage is greatly reduced, the turbine thermal efficiency and operational safety are improved, and the structure is simple, the modification cost is low, and the problem of lubricating oil-water separation caused by steam leakage is solved after the modification. The bearing temperature and vibration value are significantly reduced. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a steam turbine body in the background art;

[0015] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 3 This is a schematic diagram of the structure of the sealing shell in this utility model.

[0017] In the diagram: 1. Steam turbine body; 2. Rotor shaft; 3. Bearing housing; 4. Sealing shell; 5. High-temperature steam inlet pipe; 6. Low-pressure nitrogen inlet pipe; 7. Outer shell; 8. Inner shell; 9. Sealing comb; 10. High-temperature steam delivery pipe; 11. Regulating valve; 12. Low-pressure nitrogen delivery pipe. Detailed Implementation

[0018] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] like Figure 1 As shown, the turbine shaft end sealing device of this embodiment mainly includes a turbine body 1, a rotor shaft 2, a bearing housing 3, and a sealing assembly. The rotor shaft 2 extends laterally through the middle of the turbine body 1. There are two bearing housings 3, which are respectively installed at both ends of the rotor shaft 2 to support the rotor shaft 2. The sealing assembly is also in two sets and is distributed in a mirror image. It is used for sealing the high-pressure end and the low-pressure end, respectively. Each set is installed between a bearing housing 3 and the turbine body 1 to perform the shaft end sealing function.

[0020] Each sealing assembly includes a sealing housing 4, equipped with two main systems: a high-temperature steam inlet and a low-pressure nitrogen inlet. The sealing housing 4 consists of a double-layer structure with an outer shell 7 and an inner shell 8, and staggered sealing comb teeth 9 are provided between the outer shell 7 and the inner shell 8 to enhance the sealing effect. The core component of the high-temperature steam inlet system is the high-temperature steam inlet pipe 5, one end of which extends to the inside of the sealing housing 4, and the other end connects to the high-temperature steam delivery pipe 10. A regulating valve 11 is installed on the high-temperature steam delivery pipe 10 to control the steam delivery volume. The core component of the low-pressure nitrogen inlet system is the low-pressure nitrogen inlet pipe 6, one end of which extends to the middle of the sealing housing 4, and the other end connects to the low-pressure nitrogen delivery pipe 12. Regarding key inlet parameters, the high-temperature steam inlet pressure is 3.92 MPa, and the inlet temperature is 400℃; the low-pressure nitrogen inlet pipe 6 has a diameter of 8 mm and an inlet pressure of 30 kPa.

[0021] It should be noted that in the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0024] The technical solution of this utility model has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

Claims

1. A shaft end seal device for a turbine, comprising a turbine body (1), characterized in that: A rotor shaft (2) is provided in the middle of the turbine body (1), and bearing housings (3) are provided at both ends of the rotor shaft (2). A sealing assembly is provided between the two bearing housings (3) and the turbine body (1). The sealing assembly includes a sealing housing (4), a high-temperature steam inlet pipe (5) is connected to the middle of the sealing housing (4), and a low-pressure nitrogen inlet pipe (6) is provided at one end of the sealing housing (4) near the bearing housing (3).

2. The shaft end sealing device for turbines according to claim 1, characterized in that: The sealing housing (4) includes an outer shell (7) and an inner shell (8), and there are also staggered sealing comb teeth (9) between the outer shell (7) and the inner shell (8).

3. The shaft end seal for a turbine as set forth in claim 1, wherein: One end of the high-temperature steam inlet pipe (5) is provided with a high-temperature steam delivery pipe (10), and the other end extends to the inside of the sealed housing (4).

4. The shaft end seal arrangement for a turbine as set forth in claim 3, wherein: The high-temperature steam conveying pipe (10) is equipped with a regulating valve (11), and the inlet pressure of the high-temperature steam inlet pipe (5) is greater than 3MPa and the inlet temperature is greater than 350℃.

5. The shaft end seal for a turbine as set forth in claim 1, wherein: One end of the low-pressure nitrogen inlet pipe (6) is provided with a low-pressure nitrogen delivery pipe (12), and the other end extends to the middle of the sealing shell (4).

6. The shaft end seal arrangement for a turbine as claimed in claim 5, characterized in that: The diameter of the low-pressure nitrogen inlet pipe (6) is 5-8 mm, and the inlet pressure is less than 50 kPa.

7. The shaft end seal arrangement for a turbine as recited in claim 1, characterized by: The two sealing components are mirror-image distributed.

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