Steam sealing device capable of reducing air leakage

Abstract

The invention relates to the technical field of steam seal of steam turbines, and discloses a steam seal device capable of reducing air leakage, which comprises a static steam seal ring and a movable steam seal ring, the movable steam seal ring comprises two steam seal rings arranged in a mirror image manner, a plurality of balancing weights are arranged between the two steam seal rings, and a plurality of connecting plates are rotatably mounted on two sides of each balancing weight. The end, away from the balancing weight, of the connecting plate is rotationally connected with the two steam sealing rings, and the static steam sealing ring is fixedly connected with a static component of the steam turbine. According to the steam sealing device, the movable steam sealing ring synchronously rotating along with the rotating shaft is arranged, the gap between the movable steam sealing ring and the static steam sealing ring can be adjusted along with the change of the rotating speed of the rotating shaft, in the starting and stopping process of a steam turbine unit, the gap between the movable steam sealing ring and the static steam sealing ring is increased, collision and abrasion are avoided, and when the steam turbine unit operates according to the rated rotating speed, the rotating speed of the steam turbine unit is increased. The gap between the movable steam seal ring and the static steam seal ring is reduced, air leakage is reduced, and the energy conversion efficiency of a unit is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine steam seals, and in particular to a steam seal device capable of reducing air leakage. Background Art

[0002] The steam turbine consists of two parts: the stator and the rotor. When working, the rotor rotates at high speed and the stator is fixed. Therefore, a certain gap must be maintained between the rotor and the stator to prevent mutual friction. When the steam flows through each stage of the steam turbine, the pressure and temperature drop step by step. There is a pressure difference on both sides of the partition. When the moving blades have a reaction degree, there is also a pressure difference before and after the moving blades. In addition to the vast majority of steam flowing through the channels of the guide vanes and moving blades to do work, a small part will flow through various gaps without doing work, which becomes a loss and reduces the efficiency of the unit.

[0003] In order to reduce the air leakage in the above-mentioned gaps, in the prior art, a patent document with a publication number of CN117027966B discloses a U-shaped turbulent flow steam seal device for reducing the air leakage of the shaft end steam seal. The first device includes a steam seal body, U-shaped steam seal teeth and steam seal high teeth. Steam seal high teeth are arranged between the steam seal body and the main shaft. The steam seal high teeth are evenly distributed along the axial direction of the steam seal body. U-shaped steam seal teeth are evenly arranged between two adjacent steam seal high teeth. The U-shaped steam seal teeth change structural parameters according to different working conditions. When the rotor expands due to heat and produces axial displacement, the invention can still maintain the cooperation of multiple U-shaped steam seal teeth and bosses to form multiple throttling processes and reduce the overall air leakage. The second device includes a steam seal body, steam seal teeth and a steam seal opening. Steam seal teeth are arranged between the steam seal body and the main shaft. The steam seal teeth are evenly distributed along the axial direction of the steam seal body. The steam seal opening is located behind the first steam seal tooth at the main leakage air inlet. This invention introduces opening resistance air intake into the steam seal opening, increases the degree of vortex chaos at the main leakage air inlet, and thus hinders the main leakage air from flowing through the steam seal.

[0004] The design of steam seals should consider the size of the radial gap between the moving and static parts. The size should not be too small to prevent the moving and static parts from rubbing against each other due to temperature changes. The size should not be too large to reduce air leakage. However, in the existing steam seal structure, the gap between the comb belt and the rotating shaft is fixed, and a larger radial gap size (usually 0.5mm~0.8mm) is preferred, which leads to large air leakage and large steam work loss, which needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to solve the problem in the prior art that a larger radial gap size is preferred between the moving and static parts, resulting in large air leakage and large steam work loss, and to propose a steam seal device that reduces air leakage.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solution: a steam sealing device for reducing air leakage, including a static steam sealing ring and a dynamic steam sealing ring, wherein the inner hole wall of the static steam sealing ring is provided with an annular expansion chamber for accommodating the dynamic steam sealing ring.

[0007] The dynamic steam seal ring includes two steam seal rings arranged in a mirror image, and a plurality of counterweight blocks are arranged between the two steam seal rings. A plurality of connecting plates are rotatably installed on both sides of each counterweight block, and the ends of the connecting plates away from the counterweight blocks are rotatably connected to the two steam seal rings respectively.

[0008] The static steam seal ring is fixedly connected to the static parts of the steam turbine, the dynamic steam seal ring is slidably connected to the dynamic parts of the steam turbine, and the dynamic steam seal ring and the dynamic parts of the steam turbine rotate synchronously. The expansion chamber cover of the static steam seal ring is arranged on the outside of the static steam seal ring, and the width of the dynamic steam seal ring changes with the change of the rotation speed, so that the gap between the dynamic steam seal ring and the static steam seal ring can be adjusted, thereby reducing the gap and improving the steam seal effect.

[0009] Preferably, the moving part of the steam turbine is a rotating shaft, and a first ring groove and a second ring groove are provided on the surface of the rotating shaft, a separating ring is provided between the first ring groove and the second ring groove, guide protrusions are fixedly installed in the first ring groove and the second ring groove, a guide groove matching the guide protrusion is provided on the inner hole wall of the steam seal ring, and two steam seal rings are slidably installed in the first ring groove and the second ring groove respectively.

[0010] Magnetic rings are fixedly installed in the first ring groove and the second ring groove, a plurality of first magnetic columns are embedded on both sides of the separation ring, and a plurality of second magnetic columns are embedded on both sides of the steam seal ring. The second magnetic columns on both sides of the steam seal ring magnetically repel the magnetic ring and the first magnetic columns respectively. Under normal circumstances, the magnetic repulsion forces on both sides of the steam seal ring are equal. When the dynamic steam seal ring rotates, the centrifugal force of the counterweight block applies a lateral thrust to the steam seal ring, thereby achieving the effect of changing the gap between the steam seal ring and the inner wall of the expansion chamber.

[0011] Preferably, the cross section of the expansion chamber is an isosceles trapezoid, and the side of the steam seal ring away from the counterweight block is a conical surface, and the conical surface is parallel to the conical inner hole wall of the expansion chamber.

[0012] Preferably, the steam sealing ring is made of brass, and the thermal expansion coefficients of the materials of the rotating shaft and the static steam sealing ring are smaller than that of brass. When the steam sealing ring expands due to heat, its outer diameter increases, thereby reducing the radial gap between the dynamic steam sealing ring and the static steam sealing ring.

[0013] Preferably, the steam sealing ring is an annular structure assembled from two semicircular rings, a positioning block is fixedly provided at one end of the semicircular ring of the steam sealing ring, and the other end of the semicircular ring of the steam sealing ring is a groove. When the two semicircular steam sealing rings are assembled together, the positioning block can be inserted into the groove, and bolt holes are provided on the surface of the steam sealing ring. Bolts are inserted into the bolt holes to fix the two semicircular steam sealing rings together, thereby facilitating the sliding installation of the steam sealing ring on the surface of the rotating shaft.

[0014] Preferably, the static component of the steam turbine is a partition of the steam turbine, and the static steam sealing ring is an annular structure assembled from two semicircular rings. A mounting hole is provided in the partition, and a T-shaped groove is provided on the inner wall of the mounting hole. The static steam sealing ring is slidably installed in the telescopic T-shaped groove, and a plurality of elastic metal sheets are fixedly installed on the outer surface of the static steam sealing ring. The elastic metal sheets can be deformed to press against the inner wall of the T-shaped groove, thereby facilitating the installation of the static steam sealing ring in the partition.

[0015] Preferably, a comb ring is installed on the surface of the rotating shaft, a separation groove is opened on the inner hole wall of the static steam seal ring, and the comb ring is arranged in the telescopic separation groove to achieve the effect of changing the path of the steam maze channel.

[0016] The present invention has the following beneficial effects: 1. The steam seal device proposed in the present invention is provided with a dynamic steam seal ring that rotates synchronously with the rotating shaft. The gap between the dynamic steam seal ring and the static steam seal ring is adjustable as the rotation speed of the rotating shaft changes. During the start-up and shutdown process of the steam turbine unit, the gap between the dynamic steam seal ring and the static steam seal ring increases to avoid collision and friction. When the steam turbine unit operates at the rated speed, the gap between the dynamic steam seal ring and the static steam seal ring decreases, reducing the leakage and improving the energy conversion efficiency of the unit.

[0017] 2. In the steam seal device proposed in the present invention, a counterweight is arranged in the dynamic steam seal ring. During the operation of the dynamic steam seal ring, the centrifugal force of the counterweight is converted into a lateral thrust acting on the steam seal ring, and the steam seal ring approaches the inner wall of the expansion chamber, thereby reducing the axial gap between the dynamic steam seal ring and the static steam seal ring. At the same time, the steam seal ring expands due to heat, and its outer diameter increases, thereby reducing the radial gap between the dynamic steam seal ring and the static steam seal ring, increasing the steam sealing resistance, and exhausting the steam energy after the steam flows through the steam tortuous channel and the expansion chamber, thereby achieving a better steam sealing effect by increasing the steam sealing resistance.

[0018] 3. The steam seal device proposed by the present invention has a slow rotation speed of the rotating shaft when the steam turbine is stopped or in the initial startup stage, and the centrifugal force of the counterweight is small, that is, the lateral thrust on the steam seal ring is small, so that the gap between the dynamic steam seal ring and the static steam seal ring is large, which is conducive to the hot steam passing through the steam maze channel, preheating the dynamic steam seal ring and the expansion chamber, and shortening the preheating and startup time; When the steam turbine is started normally, preheated to the preset temperature, and the rotating shaft reaches the preset speed, the gap between the dynamic steam seal ring and the static steam seal ring will automatically decrease, increasing the steam seal resistance to meet the requirements of the steam seal. The whole process is automatically adjusted and controlled, so that the steam seal device can meet the requirements of the flow part steam seal, partition steam seal and shaft end steam seal of the steam turbine, and has a wider range of applications.

[0019] 4. In the steam seal device proposed in the present invention, the gap between the dynamic steam seal ring and the static steam seal ring is adjusted by the rotation speed of the rotating shaft. The high-pressure steam turbine has a high rotation speed and a large pressure difference, and has more stringent requirements on the steam seal. This design of regulating the gap size by rotation speed can better meet the operating requirements of low-pressure, medium-pressure or high-pressure steam turbines, and is more convenient to use. Moreover, during the assembly, debugging and later maintenance process, increasing or decreasing the weight of the counterweight block can change the centrifugal force of the counterweight block, that is, change the lateral thrust on the steam seal ring, and finally change the gap between the dynamic steam seal ring and the static steam seal ring. In the existing steam seal structure, the adjustment of the steam seal gap is completed by changing the diameter of the steam seal inner hole. This processing is difficult and irreversible. The dynamic steam seal ring proposed in the present invention has the effect of convenient assembly, debugging and later maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the three-dimensional structure of the steam seal device proposed by the present invention; Figure 2 A schematic diagram of the explosion structure of the steam seal device proposed by the present invention; Figure 3 This is a schematic diagram of the explosion structure of the dynamic steam seal ring proposed by the present invention; Figure 4 It is a partial cross-sectional structural diagram of the static steam seal ring and the dynamic steam seal ring; Figure 5 for Figure 4 A schematic diagram of a local enlarged structure; Figure 6 It is a schematic diagram of the three-dimensional structure of the static steam seal ring; Figure 7 The schematic diagram of the three-dimensional structure of the steam seal ring (I); Figure 8 The schematic diagram of the three-dimensional structure of the steam seal ring (II); Fig. 9 Schematic diagram of the steam seal ring stress analysis.

[0021] In the figure: 1. static steam seal ring; 2. dynamic steam seal ring; 3. expansion chamber; 4. steam seal ring; 5. counterweight; 6. connecting plate; 7. rotating shaft; 8. first ring groove; 9. second ring groove; 10. guide protrusion; 11. guide groove; 12. magnetic ring; 13. first magnetic column; 14. second magnetic column; 15. conical surface; 16. positioning block; 17. slot; 18. bolt hole; 19. partition; 20. elastic metal sheet; 21. comb ring; 22. separation groove; 23. separation ring. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] Reference Figure 1-9 A steam seal device for reducing air leakage comprises a static steam seal ring 1 and a dynamic steam seal ring 2. The inner hole wall of the static steam seal ring 1 is provided with an annular expansion chamber 3 for accommodating the dynamic steam seal ring 2. The dynamic steam seal ring 2 comprises two steam seal rings 4 arranged in a mirror image. A plurality of counterweight blocks 5 are arranged between the two steam seal rings 4. A plurality of connecting plates 6 are rotatably installed on both sides of each counterweight block 5. The ends of the connecting plates 6 away from the counterweight blocks 5 are rotatably connected to the two steam seal rings 4, such as Figure 3 , Figure 5 shown.

[0025] The static steam seal ring 1 is fixedly connected to the static parts of the steam turbine, the dynamic steam seal ring 2 is slidably connected to the dynamic parts of the steam turbine, and the dynamic steam seal ring 2 rotates synchronously with the dynamic parts of the steam turbine. The expansion chamber 3 of the static steam seal ring 1 is covered on the outside of the static steam seal ring 1, and the static steam seal ring 1 does not contact the inner wall of the expansion chamber 3.

[0026] In this embodiment, the moving part of the steam turbine is a rotating shaft 7, and a first annular groove 8 and a second annular groove 9 are provided on the surface of the rotating shaft 7. A separating ring 23 is provided between the first annular groove 8 and the second annular groove 9. Guide protrusions 10 are fixedly installed in the first annular groove 8 and the second annular groove 9. A guide groove 11 matching the guide protrusion 10 is provided on the inner hole wall of the steam seal ring 4. The two steam seal rings 4 are slidably installed in the first annular groove 8 and the second annular groove 9, respectively, that is, the steam seal ring 4 can slide back and forth along the length direction of the guide protrusion 10.

[0027] Among them, the first ring groove 8 and the second ring groove 9 are both fixedly installed with a magnetic ring 12, a plurality of first magnetic pillars 13 are embedded on both sides of the separation ring 23, and a plurality of second magnetic pillars 14 are embedded on both sides of the steam seal ring 4. The second magnetic pillars 14 on both sides of the steam seal ring 4 magnetically repel the magnetic ring 12 and the first magnetic pillars 13, respectively. Figure 5 As shown, under normal conditions, the magnetic repulsion forces on both sides of the steam seal ring 4 are equal.

[0028] The cross section of the expansion chamber 3 is an isosceles trapezoid. The side of the steam seal ring 4 away from the counterweight 5 is a conical surface 15 , and the conical surface 15 is parallel to the conical inner hole wall of the expansion chamber 3 .

[0029] The steam seal ring 4 is made of brass. The thermal expansion coefficients of the materials of the rotating shaft 7 and the static steam seal ring 1 are both smaller than that of brass. When the steam seal ring 4 is heated and expanded, its outer diameter increases, thereby reducing the radial clearance between the dynamic steam seal ring 2 and the static steam seal ring 1. When the steam seal ring 4 cools and contracts, its outer diameter decreases, thereby increasing the radial clearance between the dynamic steam seal ring 2 and the static steam seal ring 1. When the steam turbine is started cold, friction between the dynamic steam seal ring 2 and the static steam seal ring 1 can be effectively avoided.

[0030] Specifically, Figure 7 , Figure 8 As shown, the steam seal ring 4 is an annular structure assembled from two semicircular rings, one end of the semicircular ring of the steam seal ring 4 is fixedly provided with a positioning block 16, and the other end of the semicircular ring of the steam seal ring 4 is a groove 17. When the two semicircular steam seal rings 4 are assembled together, the positioning block 16 can be inserted into the groove 17, and the surface of the steam seal ring 4 is provided with a bolt hole 18. The bolt is inserted into the bolt hole 18 to fix the two semicircular steam seal rings 4 together.

[0031] In this embodiment, the stationary component of the steam turbine is a partition 19 of the steam turbine. The stationary steam seal ring 1 is an annular structure assembled from two semicircular rings. A mounting hole is provided in the partition 19, and a T-shaped slide groove is provided on the inner wall of the mounting hole. The stationary steam seal ring 1 is slidably installed in the telescopic T-shaped slide groove. A plurality of elastic metal sheets 20 are fixedly installed on the outer surface of the stationary steam seal ring 1. The elastic metal sheets 20 can be deformed to press against the inner wall of the T-shaped slide groove. Figure 6 shown.

[0032] The surface of the rotating shaft 7 is provided with a comb ring 21, and the inner hole wall of the static steam seal ring 1 is provided with a separation groove 22, and the comb ring 21 is arranged in the telescopic separation groove 22. Figure 5 , achieving the effect of changing the path of the steam tortuous channel.

[0033] Working principle: High-temperature and high-pressure steam is accelerated into the turbine, and the airflow is sprayed onto the impeller surface fixed on the rotating shaft 7, driving the rotating shaft 7 to rotate. Fig. 9 When the dynamic steam seal ring 2 rotates synchronously with the rotating shaft 7, the counterweight block 5 generates a centrifugal force F 离 , through the transmission of the connecting plate 6, the counterweight block 5 applies a thrust F to the steam seal ring 4 推 The magnetic ring 12 generates a magnetic repulsion force F on the steam seal ring 4 (or the second magnetic column 14). 磁 , when F 推 =F 磁 When the dynamic steam seal ring 2 is in a dynamic balance state, when the rotation speed of the rotating shaft 7 increases, F 离 Increase, F 推 >F 磁 When the steam seal ring 4 moves along the axial direction of the rotating shaft 7, it approaches the inner wall of the expansion chamber 3, that is, the gap between the steam seal ring 4 and the inner wall of the expansion chamber 3 ( Fig. 9B in the middle) is reduced, and the gap between the steam seal ring 4 and the magnetic ring 12 ( Fig. 9 The steam sealing resistance of the steam maze channel increases. When the steam flows through the expansion chambers 3 of each level in the steam turbine, the pressure and temperature decrease step by step, achieving the steam sealing effect.

[0034] When the turbine is stopped or just started, the rotation speed of the rotating shaft 7 is slow, and the centrifugal force F of the counterweight 5 is 离 Small, that is, the side thrust F on the steam seal ring 4 推 The smaller the gap between the dynamic steam seal ring 2 and the static steam seal ring 1, the larger the gap is, which is conducive to the hot steam passing through the steam maze channel, preheating the dynamic steam seal ring 2 and the expansion chamber 3, and shortening the preheating and startup time; When the steam turbine is started normally, preheated to a predetermined temperature, and the rotating shaft 7 reaches a predetermined speed, F 离、 F 推 Increases, the gap between the dynamic steam seal ring 2 and the static steam seal ring 1 automatically becomes smaller, and the steam sealing resistance is increased (it should be noted that due to the large amount of steam entering the expansion chamber 3 during the preheating stage, a water film is formed on the inner wall of the expansion chamber 3, and the dynamic steam seal ring 2 rotates. Under the action of centrifugal force, the water droplets condensed on the surface of the dynamic steam seal ring 2 are continuously transported to the expansion chamber 3, further increasing the steam sealing resistance), meeting the requirements of the steam seal, and realizing automatic adjustment and control in the whole process, so that the steam seal device meets the requirements of the flow part steam seal, the partition 19 steam seal and the shaft end steam seal of the steam turbine, and has a wider range of applications.

[0035] The steam sealing device proposed by the present invention has a counterweight 5 arranged in the dynamic steam sealing ring 2. During the operation of the dynamic steam sealing ring 2, the centrifugal force of the counterweight 5 is converted into a lateral thrust acting on the steam sealing ring 4, and the steam sealing ring 4 approaches the inner wall of the expansion chamber 3, thereby reducing the axial gap between the dynamic steam sealing ring 2 and the static steam sealing ring 1. At the same time, the steam sealing ring 4 expands due to heat, and its outer diameter increases, thereby reducing the radial gap between the dynamic steam sealing ring 2 and the static steam sealing ring 1, increasing the steam sealing resistance, and exhausting the steam energy after the leaked steam flows through the steam maze channel and the expansion chamber 3, thereby achieving a better steam sealing effect by increasing the steam sealing resistance.

[0036] The size of the gap between the dynamic steam seal ring 2 and the static steam seal ring 1 is adjusted by the rotation speed of the rotating shaft 7. For example, a high-pressure steam turbine has a high rotation speed and a large pressure difference, and has more stringent requirements on the steam seal. This design of regulating the gap size by rotation speed can better meet the operating requirements of low-pressure, medium-pressure or high-pressure steam turbines, and is more convenient to use. Because the steam pressure of low-pressure, medium-pressure or high-pressure steam turbines is different, the rotation speed setting is different, and the requirements for steam seals are also different; moreover, during the assembly, debugging, and later maintenance process, increasing or decreasing the weight of the counterweight block 5 can change the centrifugal force of the counterweight block 5, that is, change the lateral thrust on the steam seal ring 4, and ultimately change the size of the gap between the dynamic steam seal ring 2 and the static steam seal ring 1. The existing steam seal structure and the adjustment of the steam seal gap It is completed by changing the diameter of the inner hole of the steam seal. This processing is difficult and irreversible. The dynamic steam seal ring 2 proposed by the present invention has the effect of convenient assembly, debugging and later maintenance. It should be noted that the above-mentioned "irreversible" means that the diameter of the inner hole of the existing steam seal is turned to expand its inner hole size to achieve the purpose of increasing the gap. If the gap is too large during the debugging process after the diameter of the inner hole of the steam seal is enlarged and cannot meet the requirements of a good steam seal, the inner hole size cannot be reduced, resulting in the scrapping of the steam seal. However, the debugging process of the steam seal device proposed by the present invention is achieved by drilling a hole on the counterweight block 5 to reduce its weight, or welding on the counterweight block 5 to increase its weight. The rotation speed of the rotating shaft 7 is constant, the total mass of the counterweight block 5 is constant, and F 离 Therefore, the gap between the dynamic steam seal ring 2 and the static steam seal ring 1 can be repeatedly debugged by changing the mass of the counterweight block 5.

[0037] The steam seal device proposed in the present invention is provided with a dynamic steam seal ring 2 that rotates synchronously with the rotating shaft 7. The gap between the dynamic steam seal ring 2 and the static steam seal ring 1 is adjustable as the rotation speed of the rotating shaft 7 changes. During the start-up and shutdown process of the steam turbine unit, the gap between the dynamic steam seal ring 2 and the static steam seal ring 1 increases to avoid collision and friction. When the steam turbine unit operates at the rated speed, the gap between the dynamic steam seal ring 2 and the static steam seal ring 1 decreases to reduce the leakage and improve the energy conversion efficiency of the unit.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A steam seal device for reducing air leakage, comprising a static steam seal ring (1) and a dynamic steam seal ring (2), characterized in that: The inner hole wall of the static steam seal ring (1) is provided with an annular expansion chamber (3) for accommodating the dynamic steam seal ring (2); the dynamic steam seal ring (2) comprises two steam seal rings (4) arranged in a mirror image, a plurality of counterweight blocks (5) are arranged between the two steam seal rings (4), a plurality of connecting plates (6) are rotatably mounted on both sides of each counterweight block (5), and the ends of the connecting plates (6) away from the counterweight blocks (5) are rotatably connected to the two steam seal rings (4) respectively; the static steam seal ring (1) is fixedly connected to the static parts of the steam turbine, the dynamic steam seal ring (2) is slidably connected to the dynamic parts of the steam turbine, and the dynamic steam seal ring (2) and the dynamic parts of the steam turbine rotate synchronously, and the expansion chamber (3) of the static steam seal ring (1) is hooded on the outside of the static steam seal ring (1).

2. A steam seal device for reducing air leakage according to claim 1, characterized in that: The moving part of the steam turbine is a rotating shaft (7), a first annular groove (8) and a second annular groove (9) are provided on the surface of the rotating shaft (7), a separator ring (23) is provided between the first annular groove (8) and the second annular groove (9), guide protrusions (10) are fixedly installed in the first annular groove (8) and the second annular groove (9), a guide groove (11) matching the guide protrusion (10) is provided on the inner hole wall of the steam seal ring (4), and the two steam seal rings (4) are slidably installed in the first annular groove (8) and the second annular groove (9), respectively.

3. A steam seal device for reducing air leakage according to claim 2, characterized in that: A magnetic ring (12) is fixedly mounted in each of the first annular groove (8) and the second annular groove (9); a plurality of first magnetic columns (13) are embedded on both sides of the separation ring (23); a plurality of second magnetic columns (14) are embedded on both sides of the steam seal ring (4); and the second magnetic columns (14) on both sides of the steam seal ring (4) magnetically repel the magnetic ring (12) and the first magnetic columns (13) respectively.

4. A steam seal device for reducing air leakage according to claim 3, characterized in that: The expansion chamber (3) has a cross-section of an isosceles trapezoid, and the side of the steam seal ring (4) away from the counterweight (5) is a conical surface (15), and the conical surface (15) is parallel to the conical inner hole wall of the expansion chamber (3).

5. A steam seal device for reducing air leakage according to claim 4, characterized in that: The steam seal ring (4) is made of brass, and the thermal expansion coefficients of the materials of the rotating shaft (7) and the static steam seal ring (1) are both smaller than the thermal expansion coefficient of brass.

6. A steam seal device for reducing air leakage according to claim 5, characterized in that: The steam seal ring (4) is an annular structure formed by assembling two semicircular rings. A positioning block (16) is fixedly provided at one end of the semicircular ring of the steam seal ring (4). The other end of the semicircular ring of the steam seal ring (4) is a clamping groove (17). When the two semicircular steam seal rings (4) are assembled together, the positioning block (16) can be inserted into the clamping groove (17). Bolt holes (18) are provided on the surface of the steam seal ring (4). Bolts are inserted into the bolt holes (18) to fix the two semicircular steam seal rings (4) together.

7. A steam seal device for reducing air leakage according to claim 6, characterized in that: The stationary component of the steam turbine is a baffle (19) of the steam turbine. The stationary steam seal ring (1) is a ring structure assembled from two semicircular rings. A mounting hole is provided in the baffle (19), and a T-shaped slide groove is provided on the inner wall of the mounting hole. The stationary steam seal ring (1) is slidably installed in the telescopic T-shaped slide groove.

8. A steam seal device for reducing air leakage according to claim 7, characterized in that: A plurality of elastic metal sheets (20) are fixedly mounted on the outer surface of the static steam seal ring (1); the elastic metal sheets (20) can be deformed to press against the inner wall of the T-shaped slide groove.

9. A steam seal device for reducing air leakage according to claim 8, characterized in that: A comb tooth ring (21) is installed on the surface of the rotating shaft (7), a separation groove (22) is opened on the inner hole wall of the static steam seal ring (1), and the comb tooth ring (21) is arranged in the telescopic separation groove (22).

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