Adjustable steam seal device for steam turbine
By designing an adjustable steam seal device, the gap between the steam seal arc block and the rotor is adjusted using steam pressure, solving the problem of rubbing during gap adjustment in traditional steam seal devices, and achieving efficient operation and safety of the steam turbine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU LEE & MAN PAPER MFG
- Filing Date
- 2025-08-29
- Publication Date
- 2026-07-24
AI Technical Summary
Leakage loss in existing steam turbines is the main factor restricting efficiency improvement. Traditional rigid steam seal devices pose a risk of rubbing during clearance adjustment, affecting unit safety and efficiency.
Design an adjustable steam seal device that uses steam pressure to adjust the radial clearance between the steam seal arc block and the rotor. The automatic adjustment of the steam seal clearance is achieved through the cooperation of springs and guide rods, avoiding rubbing during start-up and shutdown.
It effectively reduces turbine leakage losses, improves thermal efficiency and unit economic performance, and ensures the safety and reliability of the unit during start-up and shutdown.
Smart Images
Figure CN224550190U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of steam turbine technology, specifically to an adjustable steam seal device for steam turbines. Background Technology
[0002] Currently, steam turbine seals can be mainly divided into three categories: shaft end seals, stationary blade diaphragm seals, and moving blade tip seals. Steam seals serve three main functions: first, to prevent or reduce steam leakage to the outside; second, to prevent or reduce high-energy steam from leaking directly into the low-energy steam chamber without doing work; and third, to prevent or reduce air leakage into the low-pressure cylinder.
[0003] In the current technology, leakage loss is the most important factor restricting the improvement of steam turbine efficiency. Leakage loss is mainly affected by the adjustment of steam seal gap. If the gap is too large, it will reduce the thermal efficiency of the steam turbine by 1.0%-1.5%. However, the traditional comb-tooth steam seal is a rigid structure. If the gap is too small, the rotor and the steam seal teeth are prone to collision and rubbing when the unit starts and stops, which will cause vibration or even equipment damage.
[0004] Therefore, there is an urgent need to propose an adjustable steam sealing device to reduce the leakage of steam turbine shaft end and flow passage while ensuring the safety performance of the unit, thereby improving the thermal efficiency of the steam turbine and the economic performance of the unit. Utility Model Content
[0005] The purpose of this utility model is to overcome the shortcomings of the prior art and provide an adjustable steam seal device for steam turbines. Steam in the steam turbine can enter the steam seal channel along the air inlet groove. With the cooperation of the steam seal and the spring, the steam seal arc block can move radially closer to or further away from the rotor, thereby achieving the purpose of adjusting the steam seal gap.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0007] An adjustable steam seal device for a steam turbine includes a steam seal body. An arc block capable of radially approaching or moving away from the rotor is provided on the inner side of the steam seal body. A steam seal channel is formed on the inner wall of the steam seal body. The rear end of the arc block is slidably installed within the steam seal channel. A spring is provided within the steam seal channel, with one end connected to the inner wall of the steam seal channel and the other end connected to the rear end of the arc block. An air inlet groove communicating with the steam seal channel is formed on the side of the arc block.
[0008] Optionally, an axial and radial clearance is provided between the steam seal arc block and the steam seal channel.
[0009] Optionally, the axial clearance between the steam seal arc block and the steam seal channel is 0.15-0.25 mm, and the radial clearance is 0.08-0.12 mm.
[0010] Optionally, the front end of the steam sealing arc block is provided with a plurality of steam sealing teeth, which are equidistantly distributed on the side of the steam sealing arc block near the rotor.
[0011] Optionally, the height of the steam seal teeth is 8-12 mm.
[0012] Optionally, the cross-section of the air inlet groove adopts a U-shaped structure, and the depth of the air inlet groove is 1 / 3 to 2 / 5 of the thickness of the steam seal block.
[0013] Optionally, a guide rod is installed in the steam seal channel, and a guide groove corresponding to the guide rod is opened at the rear end of the steam seal arc block, and one end of the guide rod is slidably embedded in the guide groove.
[0014] Optionally, the spring is slidably sleeved on the outside of the guide rod.
[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0016] (1) In this utility model, steam can enter the steam seal channel along the air inlet groove. The steam provides the closing force of the steam seal device. That is, the steam pushes the steam seal arc block from the back to move radially closer to the rotor to reduce the steam seal gap. At this time, the spring is stretched and elongated. When the machine stops, the steam pressure decreases and the spring provides the opening force for the device. The steam seal arc block moves radially away from the rotor, increasing the steam seal gap and avoiding collision.
[0017] (2) In this utility model, the preset axial and radial movable clearances are matched with the steam inlet groove to ensure that the steam seal arc block moves smoothly and improves the reliability of the device;
[0018] (3) In this utility model, the cooperation between the guide rod and the guide groove can ensure that the steam seal arc block can move radially in the specified direction, thus avoiding shaking and jamming during the movement. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the adjustable steam seal device for a steam turbine in an embodiment of this utility model;
[0020] Figure 2 This is a schematic diagram of the positional structure of the steam seal channel and the air intake channel in an embodiment of this utility model;
[0021] Figure 3 This is a schematic diagram of the structure of the steam seal arc block in an embodiment of this utility model;
[0022] Figure 4 This is a schematic diagram showing the positional structure of the guide groove and the steam seal arc block in an embodiment of this utility model;
[0023] Among them, 1. steam seal body; 2. steam seal arc block; 3. steam seal channel; 4. air inlet groove; 5. spring; 6. guide rod; 7. guide groove; 8. steam seal tooth. Detailed Implementation
[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.
[0025] Example 1, as Figures 1-4 As shown, an adjustable steam seal device for a steam turbine includes a steam seal body 1 and a steam seal arc block 2. The steam seal arc block 2 is disposed inside the steam seal body 1 and can move radially closer to or further away from the rotor, thereby realizing the adjustment of the steam seal gap during unit start-up and shutdown and avoiding rubbing.
[0026] As described above, a steam seal channel 3 is provided on the inner wall of the steam seal body 1. The rear end of the steam seal arc block 2 is slidably installed in the steam seal channel 3 and can move inward or outward in the radial direction. A spring 5 is provided in the steam seal channel 3 and is distributed radially along the steam seal body 1. One end of the spring 5 is fixedly connected to the inner wall of the steam seal channel 3, and the other end is fixedly connected to the rear end of the steam seal arc block 2. An air inlet groove 4 is provided on the side of the steam seal arc block 2, and the air inlet groove 4 is connected to the steam seal channel 3.
[0027] The rotor is installed inside the steam seal body 1 of the steam turbine. The steam seal arc block 2 is located between the rotor and the steam seal body 1. In the initial state, the spring 5 does not deform, and a large steam seal gap is maintained between the steam seal arc block 2 and the rotor. When the steam pressure is greater than the static elastic force of the spring 5, the steam seal arc block 2 is pushed towards the rotor, the spring 5 stretches and stores elastic potential energy, and the steam seal gap shrinks. When the steam pressure that pushes the steam seal arc block 2 to move inward is less than the elastic force of the spring 5 after stretching, the steam seal arc block 2 is pulled outward by the spring 5, and the steam seal gap increases.
[0028] Specifically, before the unit starts, the steam pressure inside the turbine is less than the static tension of spring 5, and the steam seal block 2 maintains the maximum gap with the rotor under the pull of spring 5. When the turbine is working normally, the steam inside enters the steam seal channel 3 through the air inlet slot 4, generating steam pressure that can overcome the static elasticity of spring 5, thereby pushing the steam seal block to move radially inward, reducing the gap between the steam seal block 2 and the rotor to reduce leakage loss. At this time, spring 5 is stretched. When the unit stops, the steam pressure is less than the elasticity of spring 5, and spring 5 contracts to pull the steam seal block 2 to move radially outward, increasing the gap between the steam seal block 2 and the rotor to avoid rubbing.
[0029] The inlet groove 4 has a U-shaped cross-section, and its depth is 1 / 3 to 2 / 5 of the thickness of the steam seal arc block 2. The U-shaped cross-section facilitates machining on the steam seal arc block 2 and ensures that steam inside the turbine smoothly enters the steam seal channel 3 along the inlet groove 4. The depth of the inlet groove 4, designed to be 1 / 3 to 2 / 5 of the thickness of the steam seal arc block 2, increases the speed at which steam enters the back of the steam seal arc block 2, giving the device a faster response time, and also ensures that the steam seal arc block 2 itself has sufficient strength to guarantee its stable operation inside the turbine.
[0030] Furthermore, axial and radial clearances are provided between the steam seal arc block 2 and the steam seal channel 3, with the axial clearance being 0.15-0.25 mm and the radial clearance being 0.08-0.12 mm. By pre-setting the axial and radial clearances between the steam seal arc block 2 and the steam seal channel 3 to ensure proper fit with the air inlet slot 4, the steam seal arc block 2 can be evenly stressed, ensuring smooth movement and thus improving the reliability of the device.
[0031] In addition, the front end of the steam sealing arc block 2 is provided with multiple steam sealing teeth 8. The multiple steam sealing teeth 8 are equally spaced on the side of the steam sealing arc block 2 near the rotor, and the height of the steam sealing teeth 8 is designed to be 8-12mm. The function of the steam sealing teeth 8 here is to minimize steam leakage based on the multi-stage throttling and eddy current effect. This structural design is existing technology, so it will not be described in detail.
[0032] In Example 2, based on Example 1, in order to improve the accuracy of the movement of the steam seal arc block 2, a guide rod 6 is installed in the steam seal channel 3.
[0033] like Figure 1 and Figure 4 As shown, guide rods 6 are radially distributed within the steam seal channel 3. A guide groove 7 is provided at the rear end of the steam seal arc block 2. The position and number of guide grooves 7 correspond to the guide rods 6. One end of the guide rod 6 is fixedly connected to the inner wall of the steam seal channel 3, and the other end is slidably embedded in the guide groove 7. A clearance fit is used between the guide rods 6 and the guide grooves 7. When the steam seal arc block 2 slides radially, the guide rods 6 move synchronously along the axial direction of the guide grooves 7, thereby improving the guiding accuracy of the steam seal arc block 2's movement.
[0034] Furthermore, the spring 5 can be slidably sleeved on the outside of the guide rod 6. When the end of the guide rod 6 moves outward relative to the steam seal arc block 2 along the guide groove 7, the spring 5 will be stretched and elongated. When the guide rod 6 moves inward, the spring 5 tends to return to its original length, thereby pulling the steam seal arc block 2 outward. This structure can ensure that the deformation direction of the spring 5 is consistent with the movement direction of the steam seal arc block 2.
[0035] Working principle:
[0036] When the unit starts or stops, the steam pressure inside the turbine is relatively low, so the spring 5 does not deform or return to its original length. The steam seal block 2 maintains the maximum gap with the rotor under the pull of the spring 5 to avoid rubbing. When the turbine is working normally, the steam inside enters the steam seal channel 3 through the air inlet slot 4, generating steam pressure that can overcome the static elastic force of the spring 5. This pushes the steam seal block to move radially inward, reducing the gap between the steam seal block 2 and the rotor to reduce leakage loss. At this time, the spring 5 is stretched.
[0037] In summary, this utility model proposes an adjustable steam seal device for steam turbines. Multiple steam seal arc blocks 2 can be combined to form a complete circle, covering the outer side of the rotor's circumference. Steam inside the steam turbine can enter the steam seal channel 3 along the inlet groove 4. With the cooperation of the steam seal arc blocks 2 and the spring 5, the steam seal arc blocks 2 can move radially closer to or further away from the rotor, thereby achieving the purpose of adjusting the steam seal gap and ensuring that the rotor and the steam seal teeth 8 will not collide or rub against each other when the steam turbine starts or stops.
[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to 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.
[0039] In the description of this utility model, it should be noted that, 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 based on the specific circumstances.
[0040] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0041] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. An adjustable steam seal device for a steam turbine, characterized in that: The device includes a steam seal body, an inner side of which is provided with a steam seal arc block that can move radially closer to or further away from the rotor, a steam seal channel is formed on the inner wall of the steam seal body, the rear end of the steam seal arc block is slidably installed in the steam seal channel, a spring is provided in the steam seal channel, one end of the spring is connected to the inner wall of the steam seal channel, the other end is connected to the rear end of the steam seal arc block, and an air inlet groove communicating with the steam seal channel is formed on the side of the steam seal arc block.
2. The adjustable steam seal device for steam turbines according to claim 1, characterized in that: An axial and radial clearance is provided between the steam seal arc block and the steam seal channel.
3. The adjustable steam seal device for steam turbines according to claim 2, characterized in that: The axial clearance between the steam seal arc block and the steam seal channel is 0.15-0.25 mm, and the radial clearance is 0.08-0.12 mm.
4. The adjustable steam seal device for steam turbines according to claim 1, characterized in that: The front end of the steam sealing arc block is provided with multiple steam sealing teeth, which are equidistantly distributed on the side of the steam sealing arc block near the rotor.
5. The adjustable steam seal device for steam turbines according to claim 4, characterized in that: The height of the steam seal teeth is 8-12mm.
6. The adjustable steam seal device for steam turbines according to claim 1, characterized in that: The air intake groove has a U-shaped cross-section, and the depth of the air intake groove is 1 / 3 to 2 / 5 of the thickness of the steam seal block.
7. The adjustable steam seal device for steam turbines according to any one of claims 1-6, characterized in that: A guide rod is installed inside the steam seal channel, and a guide groove corresponding to the guide rod is opened at the rear end of the steam seal arc block, and one end of the guide rod is slidably embedded in the guide groove.
8. The adjustable steam seal device for steam turbines according to claim 7, characterized in that: The spring is slidably sleeved on the outside of the guide rod.