Steam turbine shaft end steam seal structure
By setting up a steam supply guide cavity and a steam exhaust guide cavity in the steam seal body, combined with positive and negative pressure difference and end handle ring structure, the steam leakage problem of the turbine shaft end sealing structure is solved, and effective steam recovery and safe operation are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGFANG TURBINE CO LTD
- Filing Date
- 2025-08-08
- Publication Date
- 2026-05-19
AI Technical Summary
Existing turbine shaft end sealing structures are prone to steam leakage during operation due to thermal stress or cylinder misalignment, which affects the quality of lubricating oil and the safety of the unit.
A through-flow steam supply and exhaust chambers are set inside the steam seal body. By utilizing the difference between positive and negative pressure, the steam flow is controlled by the steam seal teeth to achieve steam recovery and isolation. Combined with the end handle ring and positioning pin structure, deformation is absorbed to ensure sealing.
It effectively reduces steam leakage, improves operational safety, prevents outside air from entering, ensures the isolation of steam inside the cylinder from the outside atmosphere, and reduces the impact of steam pressure.
Smart Images
Figure CN224260403U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of steam turbine sealing technology, specifically to a steam turbine shaft end sealing structure. Background Technology
[0002] A sealing structure is required where the turbine rotor exits at the end to prevent steam from communicating with the outside environment, leaking steam into the atmosphere, or leaking air into the internal vacuum. The industry standard for this sealing structure is a combination of end-stick seals and internal seals, such as... Figure 1 As shown, the end-hand steam seal structure is fastened to the side of the cylinder with bolts, and the side of the end-hand steam seal structure facing the rotor has steam seal teeth; the internal steam seal structure is installed inside the cylinder, and the side of the internal steam seal structure facing the rotor has steam seal teeth; a steam supply pipe is provided inside the cylinder, and the steam supply pipe is connected to the shaft seal system header; a steam supply guide cavity is formed between the two opposite surfaces of the end-hand steam seal structure and the internal steam seal structure, which is connected to the steam supply pipe; an exhaust pipe and an exhaust guide cavity connected to the exhaust pipe are provided inside the end-hand steam seal structure, and the exhaust chamber is connected to the shaft seal heater.
[0003] However, during the operation of the steam turbine, thermal stress or misalignment of the upper and lower cylinders can easily cause deformation of the end-steam seal structure, leading to steam leakage in the steam supply guide cavity. On the one hand, this causes water to be mixed into the turbine lubricating oil, resulting in excessive oil quality and affecting the lubrication of the unit's bearings; on the other hand, the high temperature of the leaked steam will heat the bearing housing, affecting the expansion of the unit and even affecting the safe operation of the unit. Utility Model Content
[0004] The technical objective of this utility model is to provide a steam turbine shaft end steam seal structure that is beneficial to reducing steam leakage and improving operational safety, in order to address the shortcomings of the prior art.
[0005] The technical solution adopted in this utility model is as follows:
[0006] A turbine shaft end steam seal structure includes an end-handle steam seal structure installed on the side of the cylinder and an internal steam seal structure installed inside the cylinder. The end-handle steam seal structure has an end-handle steam seal body and steam seal teeth connected to the bottom of the end-handle steam seal body facing the rotor end. The internal steam seal structure has an internal steam seal body and steam seal teeth connected to the bottom of the internal steam seal body facing the rotor end. Each steam seal tooth is clearance-fitted with the rotor. A steam supply pipe is provided inside the cylinder, and the steam supply pipe is under positive pressure and is connected to the shaft seal system header. An exhaust pipe is provided inside the end-handle steam seal structure, and the exhaust pipe is under negative pressure and is connected to the shaft seal heater.
[0007] The internal steam seal body is provided with a steam supply guide cavity that runs through the internal steam seal body and is connected to the steam supply pipeline. The steam pressure flowing into the steam supply guide cavity is within a preset range.
[0008] An exhaust steam guide cavity, which communicates with the exhaust pipe, is formed between the two opposing surfaces of the internal steam seal and the end handle steam seal.
[0009] The above-mentioned technical measures involve setting a steam supply guide cavity that runs through the internal steam seal body and is connected to the steam supply pipeline. An exhaust guide cavity is formed between the two opposite surfaces of the internal steam seal body and the end-hand steam seal body, which is connected to the exhaust pipeline. The steam inside the cylinder flows through the steam seal teeth. The steam seal teeth can reduce the steam pressure, so that the steam pressure flowing into the steam supply pipeline is within a preset range. Since the steam supply pipeline is under positive pressure, only a portion of the steam will flow into the steam supply guide cavity and flow into the shaft seal system header through the steam supply pipeline for recovery. The other portion of the steam flows into the exhaust guide cavity. Since the exhaust pipeline is under negative pressure, the steam can be drawn into the shaft seal heater, which helps to prevent steam leakage and improve operational safety.
[0010] Even if additional gaps appear in the exhaust steam guide cavity, the exhaust steam pipe is in a negative pressure operation state. Due to the pressure difference between the inside and outside, it is beneficial to prevent steam from flowing out of the gaps and to reduce the inflow of outside air, thus achieving the isolation of steam in the cylinder from the outside atmosphere.
[0011] Furthermore, the end handle steam seal structure also has an end handle ring, which is connected to the end handle steam seal body. The end handle ring is connected to the cylinder by bolts, and the inner ring and outer ring of the end handle ring are respectively connected to the cylinder by welding.
[0012] In the above-mentioned technical measures, the inner and outer rings of the end handle ring are connected to the cylinder by welding, which helps to avoid the problem of steam leakage caused by the gap formed by the deformation of the end handle ring, reduces the impact of the thrust generated when connected to the external pipeline on the end handle ring, and helps to ensure the gap between the steam seal teeth and the rotor.
[0013] Furthermore, the end handle ring has an annular groove, and a plurality of positioning pins are provided in the annular groove;
[0014] The end-cap steam seal body is provided with a pin hole corresponding to the positioning pin;
[0015] The end handle ring and the end handle steam seal are connected in place. The end handle steam seal is inserted into the annular groove, and the positioning pins in the annular groove are inserted one-to-one into the pin holes on the end handle steam seal.
[0016] The above-mentioned technical measures involve creating an annular groove in the end handle ring and setting a positioning pin within the annular groove. The end handle steam seal body has a corresponding pin hole on the positioning pin, so that the end handle steam seal body is positioned in the annular groove by the cooperation of the positioning pin and the pin hole. When the upper and lower cylinder bodies are misaligned due to long-term operation of the cylinder, the end handle ring will shift accordingly. Since the end handle steam seal body is positioned in the annular groove by the cooperation of the positioning pin and the pin hole, it can absorb part of the deformation, which helps to reduce the impact on the end handle steam seal body and thus helps to prevent steam leakage.
[0017] Furthermore, the internal steam seal has a fixed part and a movable part for connection with the cylinder;
[0018] The cylinder has multiple annular grooves, including a first annular groove for connecting the fixed part and a second annular groove for connecting the movable part.
[0019] The first annular groove is provided with a plurality of positioning pins, and the fixing part is provided with pin holes corresponding to the positioning pins;
[0020] The second annular groove is provided with a connecting ring, the connecting ring having a protrusion, and the movable part having a groove corresponding to the protrusion;
[0021] The cylinder and the internal steam seal are connected in place. The fixing part is inserted into the annular groove, and the positioning pins in the annular groove are inserted into the pin holes on the fixing part one by one. The protrusion of the connecting ring is embedded in the groove of the movable part to form a stop fit.
[0022] The above-mentioned technical measures, by setting a fixed part and a movable part on the internal steam seal body for connection with the cylinder, allow the internal steam seal body to expand due to the high operating temperature of the steam turbine during operation. The movable part and the connecting ring form a stop fit, which can provide a certain expansion space for the internal steam seal body and help improve stability.
[0023] Furthermore, the steam supply guide cavity is under positive pressure.
[0024] Furthermore, the exhaust steam guide cavity is under negative pressure.
[0025] Furthermore, a positive pressure gauge is provided inside the steam supply guide cavity, which is used to detect the pressure inside the steam supply guide cavity in real time.
[0026] The above-mentioned technical measures, by installing a positive pressure gauge in the steam supply guide cavity, can detect the pressure in the steam supply guide cavity in real time, which is beneficial to understand the operation of the shaft seal in real time and deal with the risk of steam leakage in advance.
[0027] Furthermore, a negative pressure gauge is provided inside the exhaust steam guide cavity, which is used to detect the pressure inside the exhaust steam guide cavity in real time.
[0028] The above-mentioned technical measures, by installing a negative pressure gauge in the exhaust steam guide cavity, can detect the pressure in the exhaust steam guide cavity in real time, which is beneficial to understand the shaft seal operation in real time and deal with the risk of steam leakage in advance.
[0029] Furthermore, the end-handle steam seal structure has multiple steam seal teeth, which are spaced apart at the bottom of the end-handle steam seal body.
[0030] The above-mentioned technical measures, by setting multiple steam sealing teeth, enable the steam pressure to be reduced step by step, which facilitates the recovery and utilization of steam.
[0031] Furthermore, the steam supply guide cavity has an annular inclined surface structure.
[0032] The above-mentioned technical measures, by setting the steam supply guide cavity as an annular inclined surface structure, facilitate the arrangement of the steam supply guide cavity position, and at the same time help to reduce the impact on the structural strength of the internal steam seal.
[0033] One or more technical solutions provided by this utility model have at least the following technical effects or advantages:
[0034] This invention features a steam supply guide cavity that runs through the internal steam seal body and connects to the steam supply pipeline. An exhaust guide cavity, connected to the exhaust pipeline, is formed between two opposing surfaces of the internal steam seal body and the end-hand steam seal body. Steam inside the cylinder flows through the steam seal teeth, which reduce the steam pressure, ensuring the steam pressure flowing into the steam supply pipeline remains within a preset range. Because the steam supply pipeline is under positive pressure, only a portion of the steam flows into the steam supply guide cavity and is recovered by flowing into the shaft seal system header through the steam supply pipeline. The remaining steam flows into the exhaust guide cavity. Because the exhaust pipeline is under negative pressure, the steam can be drawn into the shaft seal heater, which helps prevent steam leakage and improves operational safety.
[0035] Even if there are additional gaps in the exhaust steam guide cavity in this invention, the exhaust steam pipe is in a negative pressure operation state. At the same time, due to the pressure difference between the inside and outside, it is beneficial to prevent steam from flowing out of the gaps and to reduce the inflow of outside air, thus achieving the isolation of steam in the cylinder from the outside atmosphere. Attached Figure Description
[0036] The accompanying drawings, which are provided to further illustrate the embodiments of the present invention and constitute a part of the present invention, do not constitute a limitation thereof.
[0037] Figure 1 This is a schematic diagram of the existing turbine shaft end steam seal structure;
[0038] Figure 2 This is a schematic diagram of the structure of this utility model;
[0039] Among them, 1-cylinder; 2-rotor; 3-end handle steam seal body; 4-steam seal tooth; 5-internal steam seal body; 6-steam supply pipe; 7-steam exhaust pipe; 8-steam supply guide cavity; 9-steam exhaust guide cavity; 10-end handle ring; 11-bolt; 12-connecting ring. Detailed Implementation
[0040] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of this utility model and the features within them can be combined with each other.
[0041] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.
[0042] Reference Figure 2 This embodiment provides a turbine shaft end steam seal structure, including an end handle steam seal structure installed on the side of cylinder 1 and an internal steam seal structure installed inside cylinder 1. The end handle steam seal structure has an end handle steam seal body 3 and steam seal teeth 4 connected to the bottom of the end handle steam seal body 3 facing the rotor 2. The internal steam seal structure has an internal steam seal body 5 and steam seal teeth 4 connected to the bottom of the internal steam seal body 5 facing the rotor 2. Each steam seal tooth 4 is clearance-fitted with the rotor 2. A steam supply pipe 6 is provided inside cylinder 1. The steam supply pipe 6 is under positive pressure and is connected to the shaft seal system header. An exhaust pipe 7 is provided inside the end handle steam seal structure. The exhaust pipe 7 is under negative pressure and is connected to the shaft seal heater. The end handle steam seal structure has multiple steam seal teeth 4, which are spaced apart at the bottom of the end handle steam seal body 3.
[0043] The number of steam seal teeth 4 in the end handle steam seal structure is determined according to actual needs. The specific structure of the steam seal teeth 4 and the connection method between the steam seal teeth 4 and the internal steam seal body 5 and the end handle steam seal body 3 are common technical means in this field. The steam seal teeth 4 can reduce the steam pressure step by step. This embodiment will not describe them in detail.
[0044] The internal steam seal 5 is provided with a steam supply guide cavity 8 that runs through the internal steam seal 5 and is connected to the steam supply pipeline 6. The steam pressure flowing into the steam supply guide cavity 8 is within a preset range.
[0045] Among them, the steam supply guide cavity 8 is an annular inclined surface structure.
[0046] An exhaust steam guide cavity 9, which is connected to the exhaust steam pipe 7, is formed between the two opposing surfaces of the internal steam seal 5 and the end handle steam seal 3.
[0047] The preset range is set to achieve the effect of steam sealing, and can be 25Kpa to 35Kpa. The steam pressure is controlled by adjusting the number of steam sealing teeth 4 at the bottom of the internal steam seal body 5.
[0048] The end handle steam seal structure also has an end handle ring 10, which is connected to the end handle steam seal body 3. The end handle ring 10 is connected to the cylinder 1 by bolts 11. The inner ring and outer ring of the end handle ring 10 are respectively connected to the cylinder 1 by welding.
[0049] The end handle ring 10 has an annular groove, and multiple positioning pins are provided in the annular groove;
[0050] The end valve seal body 3 is provided with a pin hole corresponding to the positioning pin;
[0051] The end handle ring 10 and the end handle steam seal 3 are connected to the position. The end handle steam seal 3 is inserted into the annular groove, and the positioning pins in the annular groove are inserted into the pin holes on the end handle steam seal 3 one by one.
[0052] The internal steam seal 5 has a fixed part and a movable part for connecting with the cylinder 1;
[0053] The cylinder 1 has multiple annular grooves, including a first annular groove used as a connecting fixed part and a second annular groove used as a connecting movable part;
[0054] The first annular groove is provided with multiple positioning pins, and the fixing part is provided with pin holes corresponding to the positioning pins;
[0055] A connecting ring 12 is provided in the second annular groove. The connecting ring 12 has a protrusion, and the movable part has a groove corresponding to the protrusion.
[0056] The cylinder 1 and the internal steam seal 5 are connected to the cylinder in place. The fixed part is inserted into the annular groove, and the positioning pins in the annular groove are inserted into the pin holes on the fixed part one by one. The protrusion of the connecting ring 12 is embedded into the groove of the movable part to form a stop fit.
[0057] The steam supply guide cavity 8 is under positive pressure. A positive pressure gauge is installed inside the steam supply guide cavity 8 to monitor the pressure inside the steam supply guide cavity 8 in real time.
[0058] The exhaust steam guide chamber 9 is under negative pressure. A negative pressure gauge is installed inside the exhaust steam guide chamber 9 to monitor the pressure inside the exhaust steam guide chamber 9 in real time.
[0059] During the turbine startup phase, the cylinder 1 is in a vacuum state. The shaft sealing system supplies steam to the turbine shaft seal. The steam flows through the steam supply pipe 6 and the steam supply guide cavity 8 in sequence. Part of the steam flows into the cylinder 1 through the steam sealing teeth 4 at the bottom of the internal steam seal body 5, and the other part of the steam flows into the exhaust guide cavity 9 through the steam sealing teeth 4 at the bottom of the internal steam seal body 5. Since the exhaust guide cavity 9 and the exhaust pipe 7 are in a negative pressure operation state, the air outside the cylinder 1 will flow into the exhaust guide cavity 9 through the steam sealing teeth 4 at the bottom of the end steam seal body 3 and mix with the steam. Then, it flows into the shaft seal heater through the exhaust guide cavity 9 and the exhaust pipe 7 in sequence, realizing the vacuum inside the cylinder 1 and the isolation from the outside atmosphere.
[0060] During turbine operation, the internal pressure of cylinder 1 is relatively high. After the steam inside cylinder 1 is depressurized by the steam sealing teeth 4 at the bottom of the internal steam seal body 5, some steam flows into the steam supply guide cavity 8 and then into the shaft seal system header through the steam supply pipeline 6 due to the positive pressure operation of the steam supply guide cavity 8 and the steam supply pipeline 6. Some steam flows into the exhaust guide cavity 9 after being depressurized by the steam sealing teeth 4 at the bottom of the internal steam seal body 5. Due to the negative pressure operation of the exhaust guide cavity 9 and the exhaust pipeline 7, the air outside cylinder 1 flows into the exhaust guide cavity 9 through the steam sealing teeth 4 at the bottom of the end steam seal body 3, mixes with the steam, and then flows into the shaft seal heater through the exhaust pipeline 7, thus achieving the isolation of the high-pressure steam inside cylinder 1 from the outside atmosphere.
[0061] If the end handle ring 10 and / or the end handle steam seal body 3 malfunction and deform, resulting in a gap, the exhaust steam guide cavity 9 and the exhaust steam pipe 7 will be in a negative pressure state, allowing air from the outside atmosphere to flow into the exhaust steam guide cavity 9 or the exhaust steam pipe 7 through the gap. This situation will only increase the air content in the steam-air mixture flowing into the shaft seal heater. However, since the pressure difference between the exhaust steam guide cavity 9 and the exhaust steam pipe 7 and the atmosphere is small, the impact is minimal, and the high-pressure steam in the cylinder 1 can be isolated from the outside atmosphere.
[0062] When the turbine is running for a long time, if the upper and lower halves of the cylinder 1 are misaligned, the upper and lower halves of the end handle ring 10 will move synchronously. Since the end handle steam seal body 3 and the end handle ring 10 are connected by annular grooves and positioning pins and pin holes, they can absorb part of the deformation. At the same time, since the exhaust steam guide cavity 9 and the exhaust steam pipe 7 are in a negative pressure operation state, steam leakage will not occur, thus achieving the isolation of high-pressure steam in cylinder 1 from the outside atmosphere.
[0063] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.
[0064] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.
Claims
1. A steam turbine shaft end seal structure, comprising an end handle seal structure installed on the side of a cylinder (1) and an internal seal structure installed inside the cylinder (1), wherein the end handle seal structure has an end handle seal body (3) and a seal tooth (4) connected to the bottom of the end handle seal body (3) facing the rotor (2), and the internal seal structure has an internal seal body (5) and a seal tooth (4) connected to the bottom of the internal seal body (5) facing the rotor (2), wherein each of the seal teeth (4) is clearance-fitted with the rotor (2); a steam supply pipe (6) is provided inside the cylinder (1), the steam supply pipe (6) is under positive pressure, and the steam supply pipe (6) is connected to the shaft seal system header; an exhaust pipe (7) is provided inside the end handle seal structure, the exhaust pipe (7) is under negative pressure, and the exhaust pipe (7) is connected to the shaft seal heater; Its features are: The internal steam seal (5) is provided with a steam supply guide cavity (8) that runs through the internal steam seal (5) and is connected to the steam supply pipeline (6). The steam pressure flowing into the steam supply guide cavity (8) is within a preset range. The two opposing surfaces of the internal steam seal (5) and the end handle steam seal (3) form a steam exhaust guide cavity (9) that communicates with the exhaust pipe (7).
2. The turbine shaft end steam seal structure according to claim 1, characterized in that: The end handle steam seal structure also has an end handle ring (10), which is connected to the end handle steam seal body (3). The end handle ring (10) is connected to the cylinder (1) by bolts (11), and the inner ring and outer ring of the end handle ring (10) are respectively connected to the cylinder (1) by welding.
3. The turbine shaft end steam seal structure according to claim 2, characterized in that: The end handle ring (10) has an annular groove, and a plurality of positioning pins are provided in the annular groove; The end-cap steam seal body (3) is provided with a pin hole corresponding to the positioning pin; The end handle ring (10) and the end handle steam seal (3) are connected in place. The end handle steam seal (3) is inserted into the annular groove, and the positioning pins in the annular groove are inserted into the pin holes on the end handle steam seal (3) one by one.
4. The turbine shaft end steam seal structure according to claim 1, characterized in that: The internal steam seal (5) has a fixed part and a movable part for connecting with the cylinder (1); The cylinder (1) is provided with a plurality of annular grooves, including a first annular groove for connecting the fixed part and a second annular groove for connecting the movable part; The first annular groove is provided with a plurality of positioning pins, and the fixing part is provided with pin holes corresponding to the positioning pins; The second annular groove is provided with a connecting ring (12), the connecting ring (12) has a protrusion, and the movable part has a groove corresponding to the protrusion; The cylinder (1) and the internal steam seal (5) are connected in place. The fixing part is inserted into the annular groove, and the positioning pins in the annular groove are inserted into the pin holes on the fixing part one by one. The protrusion of the connecting ring (12) is embedded in the groove of the movable part to form a stop fit.
5. The turbine shaft end steam seal structure according to claim 1, characterized in that: The steam supply guide cavity (8) is under positive pressure.
6. The turbine shaft end steam seal structure according to claim 1, characterized in that: The exhaust steam guide cavity (9) is under negative pressure.
7. The turbine shaft end steam seal structure according to claim 5, characterized in that: A positive pressure gauge is provided inside the steam supply guide cavity (8), which is used to detect the pressure inside the steam supply guide cavity (8) in real time.
8. The turbine shaft end steam seal structure according to claim 6, characterized in that: The exhaust steam guide cavity (9) is equipped with a negative pressure gauge, which is used to detect the pressure in the exhaust steam guide cavity (9) in real time.
9. The turbine shaft end steam seal structure according to claim 1, characterized in that: The steam seal teeth (4) of the end handle steam seal structure are multiple and are arranged at intervals at the bottom of the end handle steam seal body (3).
10. The turbine shaft end steam seal structure according to claim 1, characterized in that: The steam supply guide cavity (8) has an annular inclined surface structure.