Steam seal structure of steam turbine

Abstract

The invention relates to the technical field of steam seals, in particular to a steam seal structure of a steam turbine, which is used between a stator and a rotor of the steam turbine and comprises a steam seal main body, an annular groove is formed in the inner side of the steam seal main body, and a steam seal sub body is arranged between the steam seal main body and the rotor. The side, facing the center of the steam turbine, of the steam seal sub-body is provided with a baffle arranged on the rotor in a sleeving mode, the steam seal sub-body comprises a sub-body outer side and a sub-body inner side which are oppositely arranged, the sub-body inner side is matched with the rotor, the sub-body outer side is provided with a protruding shoulder matched with the annular groove, the protruding shoulder is provided with a sliding groove, and a sliding rod is arranged in the sliding groove in a sliding mode. An elastic piece connected with one end of the sliding rod is arranged at the bottom in the sliding groove, a matching groove matched with the other end of the sliding rod is formed in the bottom of the annular groove, a first position is arranged in the matching groove and is the deepest position of the bottom of the matching groove, and the groove depth from the side, away from the baffle, of the matching groove to the first position is gradually increased; air leakage is effectively reduced, and good sealing is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of gland seals, and particularly to a gland seal structure for a steam turbine. Background Art

[0002] A steam turbine is an external combustion rotary machine that is driven by steam as a medium and converts the thermal energy of steam. The working part of the steam turbine is divided into two parts: a rotor and a stator. A certain gap must be maintained between the rotor and the stator to prevent accidents caused by mutual friction. Due to the existence of the gap, a part of the steam flows through the gap and leaks without doing work, reducing the efficiency of the steam turbine. Therefore, it is necessary to select an appropriate gland seal installation gap.

[0003] For example, on March 1, 2019, a patent with the publication number CN109404058A and the name of a gland seal for a steam turbine was announced. It is used between the rotor and the stator of a steam turbine, including a gland seal body, and a connecting body formed on the top of the gland seal body and connected to the stator; it also includes a first gland seal tooth provided on the rotor and a second gland seal tooth provided at the root of the gland seal body. The second gland seal tooth includes a city wall-type tooth opened on the side surface of the root of the gland seal body. The gland seal for the steam turbine of this invention can effectively reduce the air leakage volume and improve the efficiency of the steam turbine; however, the applicant found that there is a deformation gap between the shoulder and the groove due to component deformation, which is likely to cause steam leakage in the steam turbine chamber. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a gland seal structure for a steam turbine to solve the problem of steam leakage.

[0005] Based on the above purpose, the present invention provides a gland seal structure for a steam turbine, which is used between the stator and the rotor of the steam turbine. It includes a gland seal matrix, and the gland seal matrix includes an outer side and an inner side of the matrix that are oppositely arranged. The outer side of the matrix is cooperatively connected with the stator, and an annular groove is opened on the inner side of the matrix. A gland seal sub-body is arranged between the gland seal matrix and the rotor. A baffle sleeved on the rotor is arranged on one side of the gland seal sub-body facing the center of the steam turbine. The gland seal sub-body includes an outer side and an inner side of the sub-body that are oppositely arranged. The inner side of the sub-body is cooperatively arranged with the rotor, and a shoulder cooperatively arranged with the annular groove is arranged on the outer side of the sub-body. A sliding groove is opened on the shoulder, and a sliding rod is slidably arranged in the sliding groove. An elastic member connected to one end of the sliding rod is arranged at the bottom of the sliding groove. A mating groove cooperatively arranged with the other end of the sliding rod is opened at the bottom of the annular groove. A first position is arranged in the mating groove, and the first position is the deepest part at the bottom of the mating groove. The groove depth of the side of the mating groove away from the baffle gradually increases from the groove depth to the first position.

[0006] Optionally, the groove wall on the side of the mating groove close to the baffle is a vertical side wall, and the vertical side wall is vertically arranged.

[0007] Optionally, the mating groove is any one of a triangular groove, a conical groove, a frustum-shaped groove, a semi-frustum-shaped groove, a semi-conical groove, a hemispherical groove, and a quarter-spherical groove.

[0008] Optionally, a rotating cylinder is arranged on the side of the baffle away from the gland segment body, the rotating cylinder is sleeved on the rotor, and a plurality of fan blades are arranged on the rotating cylinder at equal angles.

[0009] Optionally, a plurality of arc-shaped guide grooves arranged at equal angles are formed on the side surface of the baffle away from the gland segment body, and the arc-shaped guide grooves are located on the outer oblique side of the rotating cylinder.

[0010] Optionally, a side opening groove is formed on the side surface of the gland parent body facing or away from the center of the steam turbine.

[0011] Optionally, a gland portion is arranged inside the segment body, and the gland portion includes a plurality of first gland teeth arranged at intervals in sequence, and a steam flow chamber is formed between two adjacent first gland teeth.

[0012] Optionally, a second gland tooth is arranged in the steam flow chamber, and a gland installation groove matched with the second gland tooth is formed on the rotor.

[0013] Advantages of the present invention: For the gland structure of a steam turbine provided by the present invention, during the cold start process of the steam turbine, the steam is relatively low, the elastic member is in a state of not being compressed, the sliding rod contacts the deepest part of the bottom of the mating groove, and the gap between the gland segment body and the rotor is in a relatively large state. Therefore, when passing through the critical speed of the rotor during startup, even if there is a large rotational vibration, it can avoid dynamic and static rubbing, ensure that the gland can play a good sealing role during the subsequent normal operation of the steam turbine, and at the same time avoid dynamic and static friction and wear of the rotor, increasing the safety during the startup of the steam turbine; when the steam turbine is operating under normal load, more steam will push the baffle to move away from the center of the steam turbine. After the axial movement of the gland segment body, the sliding rod cooperates with the mating groove, causing the sliding rod to move away from the first position in the mating groove, and the gap between the shoulder and the annular groove increases, and the gap between the gland segment body and the rotor decreases, thereby reducing steam leakage, effectively reducing the air leakage volume, achieving good sealing, improving the efficiency of the steam turbine, and affecting the efficiency of the conversion of thermal energy into mechanical energy. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 is the structural schematic diagram of the present invention; Figure 2 is Figure 1 the enlarged structural schematic diagram at position A in Figure 3 is the structural schematic diagram of the mating groove of the quarter-spherical groove of the present invention.

[0016] In the figure: 1, gland mother body; 2, gland son body; 3, annular groove; 4, shoulder; 5, chute; 6, slide bar; 7, mating groove; 8, vertical side wall; 9, baffle; 10, rotating cylinder; 11, fan blade; 12, first gland tooth; 13, steam flow chamber; 14, second gland tooth; 15, gland installation groove; 16, rotor; 17, side opening. Detailed implementation manners

[0017] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further details the present invention in conjunction with specific embodiments and with reference to the accompanying drawings.

[0018] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meaning understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0019] Such as Figures 1 to 3As shown in the figure, a gland seal structure of a steam turbine is used between the stator and the rotor 16 of the steam turbine. It includes a gland seal body 1. The gland seal body 1 includes an outer side and an inner side of the body that are oppositely arranged. The outer side of the body is cooperatively connected with the stator. An annular groove 3 is formed in the inner side of the body. A gland seal sub-body 2 is arranged between the gland seal body 1 and the rotor 16. A baffle 9 sleeved on the rotor 16 is arranged on one side of the gland seal sub-body 2 facing the center of the steam turbine. The gland seal sub-body 2 includes an outer side and an inner side of the sub-body that are oppositely arranged. The inner side of the sub-body is cooperatively arranged with the rotor 16. A shoulder 4 cooperatively arranged with the annular groove 3 is arranged on the outer side of the sub-body. A chute 5 is formed in the shoulder 4. A slide bar 6 is slidably arranged in the chute 5. An elastic member connected to one end of the slide bar 6 is arranged at the bottom of the chute 5. A mating groove 7 cooperatively arranged with the other end of the slide bar 6 is formed at the bottom of the annular groove 3. A first position is arranged in the mating groove 7. The first position is the deepest part at the bottom of the mating groove 7. The groove depth of the side of the mating groove 7 away from the baffle 9 to the groove depth of the first position gradually increases.

[0020] When the steam turbine is in the cold start process, the steam is relatively low, and the elastic member is in a state of not being compressed. The slide bar 6 contacts the deepest part at the bottom of the mating groove 7. The gap between the gland seal sub-body 2 and the rotor 16 is in a relatively large state. Thus, when the rotor 16 passes through the critical speed during startup, even if there is a large rotational vibration, it can avoid the occurrence of static-dynamic rubbing, ensure that the gland seal can play a better sealing role during the subsequent normal operation of the steam turbine, and at the same time avoid static-dynamic friction and wear of the rotor 16, increasing the safety during the startup of the steam turbine; when the steam turbine is in normal load operation, more steam will push the baffle 9 to move away from the center of the steam turbine. After the gland seal sub-body 2 axially moves, and the slide bar 6 cooperates with the mating groove 7, the slide bar 6 moves away from the first position in the mating groove 7. The gap between the shoulder 4 and the annular groove 3 increases, and the gap between the gland seal sub-body 2 and the rotor 16 decreases, thereby reducing steam leakage, effectively reducing the air leakage volume, achieving good sealing, improving the efficiency of the steam turbine, and affecting the efficiency of the conversion of thermal energy into mechanical energy.

[0021] The groove wall of the side of the mating groove 7 close to the baffle 9 is a vertical side wall 8, and the vertical side wall 8 is vertically arranged.

[0022] The shape of the mating groove 7 can be a triangular groove, a conical groove, a frustum-shaped groove, a semi-frustrum-shaped groove, a semi-conical groove, a hemispherical groove, a quarter-spherical groove, etc.

[0023] On the side of the baffle 9 away from the gland body 2, a rotating cylinder 10 is provided. The rotating cylinder 10 is sleeved on the rotor 16. A plurality of fan blades 11 are arranged at equal angles on the rotating cylinder 10. When the steam turbine is operating under normal load, more steam will push the baffle 9 to move away from the center of the steam turbine. In addition, the steam flow blows towards the fan blades 11 to drive the fan blades 11 to rotate, thereby driving the gland body 2 to deflect slightly. After the axial and radial movement of the gland body 2, the slide bar 6 cooperates with the mating groove 7, causing the slide bar 6 to move away from the first position in the mating groove 7, increasing the gap between the shoulder 4 and the annular groove 3, and reducing the gap between the gland body 2 and the rotor 16, thereby reducing steam leakage, effectively reducing the air leakage volume, achieving good sealing, improving the efficiency of the steam turbine, and affecting the efficiency of the conversion of thermal energy into mechanical energy.

[0024] On the side of the baffle 9 away from the gland body 2, a plurality of arc-shaped guide grooves are provided at equal angles. The arc-shaped guide grooves are located on the outer oblique side of the rotating cylinder 10, facilitating the diversion treatment of the steam flow blowing onto the baffle 9.

[0025] On the side of the gland matrix 1 facing or away from the center of the steam turbine, a side slot 17 is provided, facilitating the steam flow to enter the side slot 17, thereby reducing the impact of the steam flow on the connection between the gland matrix 1 and the stator.

[0026] A gland part is arranged inside the gland body. The gland part includes a plurality of first gland teeth 12 arranged at intervals in sequence. A steam flow-through chamber 13 is formed between two adjacent first gland teeth 12.

[0027] A second gland tooth 14 is arranged in the steam flow-through chamber 13. A gland installation groove 15 is provided on the rotor 16 and is arranged in cooperation with the second gland tooth 14.

[0028] Through the arrangement of the first gland teeth 12 and the second gland teeth 14, when the steam flow passes through the gland clearance, it is continuously throttled, the pressure is reduced, the kinetic energy increases, and a large number of eddies are formed in each steam flow-through chamber 13, converting the kinetic energy into thermal energy, increasing the leakage flow length, and increasing the resistance of the leakage flow. Thus, at the end outlet, the flow rate is greatly reduced, thereby reducing the leakage flow rate and improving the sealing effect.

[0029] During the cold start process of the steam turbine, the steam is at a low level, and the gap between the gland body 2 and the rotor 16 is in a large state. Even under large rotational vibrations, the occurrence of static-dynamic rubbing can be avoided. Not only is the wear of the first gland teeth 12 and the second gland teeth 14 avoided, ensuring that the gland can play a good sealing role during the subsequent normal operation of the steam turbine, but also the static-dynamic friction and the wear of the rotor 16 are avoided, increasing the safety during the start of the steam turbine.

[0030] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention is limited to these examples. The present invention is not limited to the above-described embodiments, that is, it does not mean that the present invention must rely on the above methods and structures to be implemented; within the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

[0031] Embodiments of the present invention are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A steam seal structure for a steam turbine, used between a stator and a mover (16) of a steam turbine, comprising a steam seal mother body (1), wherein the steam seal mother body (1) comprises a mother body outer side and a mother body inner side arranged opposite to each other, wherein the mother body outer side is cooperatively connected with the stator, and an annular groove (3) is formed on the mother body inner side, and a steam seal sub-body (2) is arranged between the steam seal mother body (1) and the mover (16), characterized in that: A baffle (9) sleeved on the mover (16) is arranged on the side of the steam seal sub-body (2) facing the center of the steam turbine. The steam seal sub-body (2) includes a sub-body outer side and a sub-body inner side which are arranged opposite to each other. The sub-body inner side is arranged to cooperate with the mover (16). The sub-body outer side is provided with a convex shoulder (4) which is arranged to cooperate with the annular groove (3). The convex shoulder (4) is provided with a slide groove (5). A slide rod (6) is slidably arranged in the slide groove (5). An elastic member connected to one end of the slide rod (6) is arranged at the bottom of the slide groove (5). A matching groove (7) which is arranged to cooperate with the other end of the slide rod (6) is arranged at the bottom of the annular groove (3). A first point is arranged in the matching groove (7). The first point is the deepest point at the bottom of the matching groove (7). The groove depth of the matching groove (7) on the side away from the baffle (9) gradually increases to the first point.

2. A steam seal structure for a steam turbine according to claim 1, characterized in that: The groove wall of the matching groove (7) on the side close to the baffle (9) is a vertical side wall (8), and the vertical side wall (8) is vertically arranged.

3. The steam seal structure of a steam turbine according to claim 1, characterized in that: The matching groove (7) is any one of a triangular groove, a conical groove, a truncated cone groove, a semi-truncated cone groove, a semi-conical groove, a hemispherical groove, and a quarter-spherical groove.

4. A steam seal structure for a steam turbine according to claim 3, characterized in that: A rotating drum (10) is arranged on the side of the baffle (9) away from the steam seal sub-body (2), the rotating drum (10) is sleeved on the mover (16), and a plurality of fan blades (11) are arranged at equal angles on the rotating drum (10).

5. A steam seal structure for a steam turbine according to claim 4, characterized in that: A side surface of the baffle (9) away from the steam seal sub-body (2) is provided with a plurality of arc-shaped guide grooves arranged at equal angles, and the arc-shaped guide grooves are located on the outer oblique side of the rotating drum (10).

6. The steam seal structure of a steam turbine according to claim 1, characterized in that: A side groove (17) is formed on a side of the steam seal matrix (1) facing toward or away from the center of the steam turbine.

7. The steam seal structure of a steam turbine according to claim 1, characterized in that: A steam sealing portion is arranged inside the sub-body, and the steam sealing portion comprises a plurality of first steam sealing teeth (12) arranged in sequence and spaced apart, and a steam flow chamber (13) is formed between two adjacent first steam sealing teeth (12).

8. The steam seal structure of a steam turbine according to claim 7, characterized in that: A second steam seal tooth (14) is arranged in the steam circulation chamber (13), and a steam seal installation groove (15) cooperating with the second steam seal tooth (14) is provided on the mover (16).

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