CN112923060B - Multi-end-face self-regulation and starting steam turbine shaft end sealing method - Google Patents

Multi-end-face self-regulation and starting steam turbine shaft end sealing method Download PDF

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Publication number
CN112923060B
CN112923060B CN202110155736.6A CN202110155736A CN112923060B CN 112923060 B CN112923060 B CN 112923060B CN 202110155736 A CN202110155736 A CN 202110155736A CN 112923060 B CN112923060 B CN 112923060B
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cavity
pressure
ring
static ring
flexible static
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CN112923060A (en
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柏燕
林朝晖
连加俤
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Hebei Huatong Heavy Machinery Manufacturing Co ltd
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Hebei Huatong Heavy Machinery Manufacturing Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3268—Mounting of sealing rings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3284—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings characterised by their structure; Selection of materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/3464—Mounting of the seal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • F16J15/447—Labyrinth packings

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)

Abstract

The invention provides a multi-end self-regulating and starting turbine shaft end sealing method, wherein high-pressure medium fluid in a first-stage cavity passes through a first pressure regulating cavity, the first pressure regulating cavity releases fluid pressure to enter a pressure cavity of a first flexible static ring, and the pressure cavity of the first flexible static ring expands to enable the first flexible static ring and the first movable ring to be compressed to form a first-stage friction pair for sealing; the second-stage sealing of the flexible static ring II and the movable ring II is not started at first, and only when the second-stage cavity is pressurized by fluid leakage, the leaked fluid passes through the pressure regulating cavity II, the pressure regulating cavity II releases the fluid pressure to enter the pressure cavity of the flexible static ring II, and the flexible static ring II is tightly pressed with the movable ring II to form a second-stage friction pair for sealing; the third-stage sealing of the flexible static ring III and the movable ring III is not started at first, and the leaked fluid passes through the pressure regulating cavity III when the third-stage cavity is pressurized by fluid leakage, the pressure of the fluid is released by the pressure regulating cavity III and enters the pressure cavity of the flexible static ring III, and the flexible static ring III is tightly pressed with the movable ring III to form a third-stage friction pair for sealing.

Description

Multi-end-face self-regulation and starting steam turbine shaft end sealing method
Technical Field
The invention belongs to the technical field of mechanical sealing, and particularly relates to a multi-end surface self-regulating and starting steam turbine shaft end sealing method.
Background
Relatively rotating sealed fluid devices such as steam turbines, centrifugal compressors include a rotor and a stator, typically a housing, with the rotor and housing rotating and stationary, with the housing containing a dielectric fluid, the rotating and stationary components requiring sealing to ensure fluid pressure within the cavity, and the shaft ends typically being sealed mechanically (mechanical end seals). The mechanical seal device comprises a moving ring and a stationary ring. The movable ring is fixedly arranged on the shaft sleeve or the shaft and rotates along with the shaft, the static ring is arranged on the static ring seat, the static ring seat is arranged on the equipment shell, and the static ring and the movable ring are tightly pressed by the spring so as to realize the sealing between the rotating part and the static part. Leakage of the rotating equipment media fluid often occurs at the end gap between the stationary and moving rings; in addition, seal failure will result from wear of the moving and stationary rings. In order to reduce the leakage of medium fluid at the shaft end of the rotating equipment, the shaft end sealing method of the steam turbine needs to be optimally designed.
Disclosure of Invention
The invention aims to solve the technical problems and provides a steam turbine shaft end sealing method for multi-end self-regulation starting.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a multi-end surface self-regulation starting turbine shaft end sealing method is used for sealing a gap between a turbine shell and a rotating shaft, a high-pressure medium fluid cavity is arranged in the turbine shell, a low-pressure atmosphere side is arranged outside the turbine shell, a static ring seat is fixedly arranged on the turbine shell, a flexible static ring I, a flexible static ring II and a flexible static ring III are fixedly arranged on the static ring seat, and the diameters of the flexible static ring I, the flexible static ring II and the flexible static ring III are sequentially reduced; the rotating shaft is fixedly provided with a moving ring seat, and the moving ring seat is fixedly provided with a moving ring I, a moving ring II and a moving ring III which correspond to the flexible static ring I, the flexible static ring II and the flexible static ring in a three-phase manner; the outer ends of the flexible static rings are provided with friction parts, the pressure cavities of the flexible static rings are arranged in the flexible static rings, the flexible static rings are in contact sealing with corresponding movable rings through the friction parts by expansion of the pressure cavities of the flexible static rings, when three flexible static rings are in contact sealing with the corresponding movable rings, the high-pressure medium fluid cavity in the turbine shell is divided into a first-stage cavity at the periphery of the first flexible static ring, a second-stage cavity between the second flexible static ring and the first flexible static ring, and a third-stage cavity between the third flexible static ring and the second flexible static ring; the pressure regulator is provided with a first pressure regulating cavity, a second pressure regulating cavity and a third pressure regulating cavity, the pressure cavity of the flexible static ring I is connected with the first-stage cavity through the first pressure regulating cavity, the pressure cavity of the flexible static ring II is connected with the second-stage cavity through the second pressure regulating cavity, and the pressure cavity of the flexible static ring III is connected with the third-stage cavity through the third pressure regulating cavity; the high-pressure medium fluid in the first-stage cavity passes through the first pressure regulating cavity, the first pressure regulating cavity releases fluid pressure to enter the pressure cavity of the first flexible static ring, and the pressure cavity of the first flexible static ring expands, so that the first flexible static ring and the first movable ring are tightly pressed to form a first-stage friction pair for sealing; the second-stage sealing of the flexible static ring II and the movable ring II is not started at first, and only when the second-stage cavity is pressurized by fluid leakage, the leaked fluid passes through the pressure regulating cavity II, the pressure regulating cavity II releases the fluid pressure to enter the pressure cavity of the flexible static ring II, and the flexible static ring II is tightly pressed with the movable ring II to form a second-stage friction pair for sealing; the third-stage sealing of the flexible static ring III and the movable ring III is not started at first, and the leaked fluid passes through the pressure regulating cavity III when the third-stage cavity is pressurized by fluid leakage, the pressure of the fluid is released by the pressure regulating cavity III and enters the pressure cavity of the flexible static ring III, and the flexible static ring III is tightly pressed with the movable ring III to form a third-stage friction pair for sealing.
Preferably, the pressure regulator comprises the following pressure regulating methods: a first spring and a first plunger are arranged in the first pressure regulating cavity, the first spring is abutted against one end of the first plunger, so that the first plunger seals a communication port between the first pressure regulating cavity and the first-stage cavity, when the pressure reaches a certain degree, the first plunger is pushed away, the communication port releases fluid pressure to enter a pressure cavity of the first flexible static ring, the first flexible static ring expands, and the first flexible static ring is compressed with the first movable ring; a second spring and a second plunger are arranged in the pressure regulating cavity II, the second spring is abutted against one end of the second plunger, so that the second plunger seals a communication port between the pressure regulating cavity II and the second-stage cavity, when the pressure reaches a certain degree, the second plunger is pushed away, the communication port releases the fluid pressure to enter a pressure cavity of the second flexible stationary ring, the second flexible stationary ring expands, and the second flexible stationary ring is tightly pressed with the second movable ring; the pressure regulating cavity III is internally provided with a spring III and a plunger III, the spring III is abutted to one end of the plunger III, so that the plunger III seals a communication port between the pressure regulating cavity III and a third-stage cavity, when the pressure reaches a certain degree, the plunger III is pushed away, the communication port releases fluid pressure to enter a pressure cavity of the flexible static ring III, the flexible static ring III expands, and the flexible static ring III is tightly pressed with the movable ring III.
Preferably, the sealing method further comprises: the shell of the steam turbine comprises an end cover, the end cover is matched with a rotating shaft of the steam turbine to form fourth-stage seal, and a plurality of annular seal teeth which are sequentially arranged are arranged on the inner surface of the end cover matched with the rotating shaft.
After the technical scheme is adopted, the invention has the following advantages:
the high pressure fluid passes through the medium fluid chamber at the periphery of the flexible static ring one to reach the first-stage seal of the flexible static ring one and the movable ring one. The first flexible static ring is a structure capable of injecting air and pressure into the internal pressure cavity, and the first flexible static ring and the first movable ring are pressed by injecting air and pressure into the pressure cavity of the first flexible static ring. The pressure of the first injection to the flexible stationary ring is the fluid medium pressure using the medium fluid chamber, i.e. in the present invention, regulated by the steam pressure in the turbine. Because the pressure of the fluid medium in the medium fluid chamber is relatively high, and the flexible static ring I does not need such high pressure, the pressure regulator is designed to regulate the pressure of the fluid entering the flexible static ring I pressure chamber. The principle of the pressure regulator is that a first plunger is used for sealing a communication port between a first pressure regulating cavity and a medium fluid cavity, when the pressure reaches a certain degree, the first plunger is pushed away, and the communication port releases the fluid pressure to enter the pressure cavity of a first flexible static ring, so that the first flexible static ring expands, and the first flexible static ring is compressed with a first movable ring.
The second-stage sealing of the second flexible static ring and the first flexible static ring is not started at first, and the second flexible static ring and the first flexible static ring are pressed tightly to form a friction pair for sealing only when the cavity between the second flexible static ring and the first flexible static ring is pressurized by fluid leakage. When the first-stage seal fails, fluid leaks into a cavity between the second flexible static ring and the first flexible static ring, the second plunger is pushed away, and the communication port releases fluid pressure to enter a pressure cavity of the second flexible static ring, so that the second flexible static ring expands, and the second flexible static ring is compressed with the second movable ring. On the one hand, the structure reduces friction torque generated by sealing so as to reduce power consumption, and on the other hand, when the first-stage sealing is damaged, the second-stage sealing automatically expands and seals, so that the overall reliability of the steam turbine is improved, and the service life of the sealing device is prolonged.
The third-stage sealing of the flexible static ring III and the movable ring III is not started at first, and the flexible static ring III and the movable ring III are pressed tightly to form a friction pair for sealing only when the cavity between the flexible static ring III and the flexible static ring II is pressurized by fluid leakage. When the second-stage seal fails, fluid leaks into a cavity between the third flexible static ring and the second flexible static ring, the third plunger is pushed away, and the communication port releases fluid pressure to enter a pressure cavity of the third flexible static ring, so that the third flexible static ring expands, and the third flexible static ring is tightly pressed with the third movable ring. On the one hand, the structure reduces friction torque generated by sealing so as to reduce power consumption, and on the other hand, when the second-stage sealing is damaged, the third-stage sealing automatically expands and seals, so that the overall reliability of the steam turbine is improved, and the service life of the sealing device is prolonged.
And a labyrinth sealing structure is further arranged between the end cover and the rotating shaft and used for preventing the medium fluid from directly flushing to the atmosphere after the first-stage sealing is failed. The labyrinth sealing structure is characterized in that a plurality of annular sealing teeth which are sequentially arranged are arranged on the inner surface of the end cover matched with the rotating shaft, a series of interception gaps and expansion cavities are formed among the teeth, and a sealed medium generates a throttling effect when passing through the gaps of the labyrinth to achieve the purpose of leakage resistance.
In conclusion, the shaft end sealing method of the steam turbine has the advantages of high reliability, self-regulating sealing, low torque, low power loss and good sealing performance.
Drawings
FIG. 1 is a schematic structural view of a multi-terminal self-regulating enabled turbine shaft end seal;
FIG. 2 is a schematic structural view of the flexible stationary ring, with the flexible stationary ring in an unexpanded state;
FIG. 3 is a schematic view of the structure of the flexible stationary ring as it expands and contacts the moving ring;
FIG. 4 is a schematic structural view of a flexible static ring, when the flexible static ring is fully inflated without blocking;
FIG. 5 is an enlarged view of a portion of FIG. 1 at A;
in the figure:
1-a rotating shaft; 2-a casing; 201-a first seal ring mounting groove; 202-a first sealing ring; 3-stationary ring seat; 301-a stationary ring-mounting groove; 302-a second stationary ring mounting groove; 303-a stationary ring three mounting groove; 4-end caps; 401-annular seal teeth; 5-a movable ring seat; 7-flexible static ring I; 8-a flexible static ring II; 9-a flexible static ring III; 11-a first ring; 12-a second moving ring; 13-a third moving ring; 15-an anti-rotation pin; 16-friction part; 17-a pressure chamber; 18-a pressure regulator; 1801-pressure regulating cavity I; 1802-pressure regulating cavity II; 1803-pressure regulating cavity III; 19-spring one; 20-plunger one; 21-spring two; 22-a second plunger; 23-an outer tire layer; 2301—a clamping portion; 24-an inner tire layer; 2401-a through hole; 25-mounting seats; 26-spring three; 27-plunger three.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1-5, a multi-end self-regulating turbine shaft end sealing device comprises a shell, a rotating shaft 1, a movable ring seat 5 and a pressure regulator 18. A medium fluid cavity is arranged between the shell and the rotating shaft 1, and for a steam turbine, the medium fluid in the medium fluid cavity is steam.
In order to conveniently express the structural relation of all the components, the invention distinguishes the left and right of the shaft end sealing device.
The shell comprises a shell 2, a stationary ring seat 3 and an end cover 4 which are connected in sequence. The left end face of the stationary ring seat 3 is fixedly connected with the casing 2, and the right end face of the stationary ring seat 3 is fixedly connected with the end cover 4. The contact surface of the machine shell 2 and the stationary ring seat 3 is provided with a first sealing ring installation groove 201, and a first sealing ring 202 is arranged in the first sealing ring installation groove 201. The left side of the shaft end sealing device is the air sealing side, namely the high-pressure medium side, and the right side is the atmosphere side, namely the low-pressure side.
The left end face of the static ring seat 3 is provided with a static ring one mounting groove 301, a static ring two mounting groove 302 and a static ring three mounting groove 303, a flexible static ring one 7 is arranged in the static ring one mounting groove 301, a flexible static ring two 8 is arranged in the static ring two mounting groove 302, and a flexible static ring three 9 is arranged in the static ring three mounting groove 303. The diameters of the first flexible static ring 7, the second flexible static ring 8 and the third flexible static ring 9 are sequentially reduced, and the first flexible static ring 7, the second flexible static ring 8 and the third flexible static ring 9 are coaxially arranged with the rotating shaft 1.
The movable ring seat 5 is fixedly arranged on the rotating shaft 1 through a set screw, and the movable ring seat 5 is fixedly provided with a movable ring I11, a movable ring II 12 and a movable ring III 13 which correspond to the flexible static ring I7, the flexible static ring II 8 and the flexible static ring III 9.
Each flexible stationary ring comprises a friction portion 16 in contact with and sealed against the corresponding movable ring and a pressure chamber 17. The flexible static ring I7, the flexible static ring II 8 and the flexible static ring III 9 respectively comprise an outer tire layer 23 and an inner tire layer 24, the friction part 16 is fixedly arranged on the end face of the outer tire layer 23, the inner tire layer 24 is arranged in the outer tire layer 23, and the inner cavity of the inner tire layer 24 is the pressure cavity 17.
The pressure regulator 18 is internally provided with a first pressure regulating cavity 1801, a second pressure regulating cavity 1802 and a third pressure regulating cavity 1803, the first pressure regulating cavity 1801 is communicated with a medium fluid cavity at the periphery of the first flexible static ring 7, the first pressure regulating cavity 1801 is communicated with a pressure cavity 17 of the first flexible static ring 7, the first pressure regulating cavity 1801 is internally provided with a first spring 19 and a first plunger 20, the first spring 19 is abutted against one end of the first plunger 20, so that the first plunger 20 seals a communication port between the first pressure regulating cavity 1801 and the medium fluid cavity at the periphery of the first flexible static ring 7; the second pressure regulating cavity 1802 is communicated with a cavity between the second flexible static ring 8 and the first flexible static ring 7, the second pressure regulating cavity 1802 is communicated with a pressure cavity 17 of the second flexible static ring 8, a second spring 21 and a second plunger 22 are arranged in the second pressure regulating cavity 1802, and the second spring 21 is abutted against one end of the second plunger 22, so that the second plunger 22 seals a communication port of the cavity between the second pressure regulating cavity 1802 and the second flexible static ring 8 and the first flexible static ring 7; the pressure regulating cavity III 1803 is communicated with a cavity between the flexible static ring III 9 and the flexible static ring II 8, the pressure regulating cavity III 1803 is communicated with a pressure cavity of the flexible static ring III 9, a spring III 26 and a plunger III 27 are arranged in the pressure regulating cavity III 1803, and the spring III 26 is abutted to one end of the plunger III 27, so that the plunger III 27 seals a communication port of the cavity between the pressure regulating cavity III 1803 and the flexible static ring III 9 and the flexible static ring II 8.
The friction portion 16 has a convex ring shape. The friction portion 16 is made of silicon carbide or graphite, and the outer tire layer 23 and the inner tire layer 24 are made of rubber. The inner tire layer 24 is provided with a plurality of through holes 2401 which are communicated with the cavity between the pressure cavity 17 and the outer tire layer 23 and the inner tire layer 24, and when the pressure cavity 17 is injected, gas enters the cavity between the outer tire layer 23 and the inner tire layer 24 through the through holes 2401. The two-layer structure of the outer tire layer 23 and the inner tire layer 24 plays a certain role in buffering, and the friction part 16 is prevented from being broken.
The flexible static ring I7, the flexible static ring II 8 and the flexible static ring III 9 further comprise mounting seats 25, the outer tire layer 23 and the inner tire layer 24 are mounted in the mounting seats 25, the outer tire layer 23 comprises clamping portions 2301, and the outer tire layer 23 is clamped in the mounting seats 25 through the clamping portions 2301, so that the outer tire layer 23 and the inner tire layer 24 are prevented from falling off due to recoil force of gas injection of the pressure cavity 17. The right end face of the inner tire layer 24 is fixedly connected to the right side face of the inner surface of the outer tire layer 23.
The friction surface of the friction part 16 is provided with a plurality of coaxially arranged friction rings 1601. The friction ring 1601 has a semicircular cross section. Contact wear swarf can enter the grooves between friction rings 1601, avoiding swarf from accelerating wear of the moving ring end face or flexible static ring friction portion 16. In addition, the friction rings 1601 form a multi-point seal with a large end face specific pressure and a good sealing effect.
The friction ring 1601 may be made to be highly non-uniform, i.e. peaks are not equally high. After the highest friction ring 1601 peak wears, the next highest friction ring 1601 peak is in contact with the moving ring. The service life of the flexible static ring is prolonged. The friction ring 1601 has a peak height difference of 0-100 microns. Further, the height of the friction ring 1601 may be configured to gradually decrease from the outside to the inside.
The end cover 4 is matched with the rotating shaft 1, and a plurality of annular sealing teeth 401 which are sequentially arranged are arranged on the inner surface of the end cover 4 matched with the rotating shaft 1.
Working principle: the left side of the sealing device is a gas sealing side and a high-pressure medium side, the right side is an atmosphere side and a low-pressure side, and high-pressure fluid reaches the first-stage sealing of the flexible static ring I7 and the movable ring I11 through a medium fluid cavity at the periphery of the flexible static ring I7.
The flexible static ring 7 is a structure capable of injecting air and pressure into the internal pressure cavity 17, and the air and pressure are injected into the pressure cavity 17 of the flexible static ring 7 so that the flexible static ring 7 and the movable ring 11 are compressed. The pressure injected into the flexible stator ring 7 is the fluid medium pressure using the medium fluid chamber, i.e. in the present invention, regulated by the steam pressure in the turbine. Since the pressure of the fluid medium in the medium fluid chamber is relatively high, and such a high pressure is not required in the flexible stationary ring 7, the pressure regulator 18 is designed to regulate the pressure of the fluid entering the pressure chamber 17 of the flexible stationary ring 7. The principle of the pressure regulator 18 is that a communication port between the pressure regulating cavity one 1801 and the medium fluid cavity is blocked by the plunger one 20, when the pressure reaches a certain degree, the plunger one 20 is pushed away, and the communication port releases the fluid pressure to enter the pressure cavity 17 of the flexible static ring one 7, so that the flexible static ring one 7 expands, and the flexible static ring one 7 is compressed with the movable ring one 11.
The second-stage sealing of the flexible static ring II 8 and the movable ring II 12 is not started at first, and the flexible static ring II 8 and the movable ring II 12 are pressed tightly to form a friction pair for sealing only when the cavity between the flexible static ring II 8 and the flexible static ring I7 is pressurized by fluid leakage. When the first-stage seal fails, fluid leaks into a cavity between the flexible static ring II 8 and the flexible static ring I7, the plunger II 22 is pushed away, and the communication port releases fluid pressure to enter the pressure cavity 17 of the flexible static ring II 8, so that the flexible static ring II 8 expands, and the flexible static ring II 8 is compressed with the movable ring II 12. On the one hand, the structure reduces friction torque generated by sealing so as to reduce power consumption, and on the other hand, when the first-stage sealing is damaged, the second-stage sealing automatically expands and seals, so that the overall reliability of the steam turbine is improved, and the service life of the sealing device is prolonged.
The third-stage sealing of the flexible static ring III 9 and the movable ring III 13 is not started at first, and the flexible static ring III 9 and the movable ring III 13 are pressed tightly to form a friction pair for sealing only when the cavity between the flexible static ring III 9 and the flexible static ring II 8 is pressurized by fluid leakage. When the second-stage seal fails, fluid leaks into a cavity between the flexible static ring III 9 and the flexible static ring II 8, the plunger III 27 is pushed away, and the communication port releases fluid pressure to enter the pressure cavity 17 of the flexible static ring III 9, so that the flexible static ring III 9 expands, and the flexible static ring III 9 is compressed with the movable ring III 13. On the one hand, the structure reduces friction torque generated by sealing so as to reduce power consumption, and on the other hand, when the second-stage sealing is damaged, the third-stage sealing automatically expands and seals, so that the overall reliability of the steam turbine is improved, and the service life of the sealing device is prolonged.
And a labyrinth sealing structure is further arranged between the end cover 4 and the rotating shaft 1 and is used for preventing the medium fluid from directly flushing to the atmosphere after the first-stage sealing is failed. The labyrinth sealing structure is characterized in that a plurality of annular sealing teeth 401 which are sequentially arranged are arranged on the inner surface of the end cover 4 matched with the rotating shaft 1, a series of interception gaps and expansion cavities are formed between the teeth, and a sealed medium generates a throttling effect when passing through the gaps of the labyrinth to achieve the purpose of leakage prevention.
Based on the sealing device, the invention provides a multi-end self-regulation and starting turbine shaft end sealing method which is used for sealing a gap between a turbine shell and a rotating shaft 1, wherein a high-pressure medium fluid cavity is arranged in the turbine shell, and a low-pressure atmosphere side is arranged outside the turbine shell.
The shaft end sealing method of the steam turbine comprises the following steps: a static ring seat 3 is fixedly arranged on a shell of the steam turbine, a flexible static ring I7, a flexible static ring II 8 and a flexible static ring III 9 are fixedly arranged on the static ring seat 3, and the diameters of the flexible static ring I7, the flexible static ring II 8 and the flexible static ring III 9 are sequentially reduced. The rotating shaft 1 is fixedly provided with a moving ring seat 5, and the moving ring seat 5 is fixedly provided with a moving ring I11, a moving ring II 12 and a moving ring III 13 which correspond to the flexible static ring I7, the flexible static ring II 8 and the flexible static ring III 9. Each flexible static ring is provided with a friction part 16 at the outer end, each flexible static ring is internally provided with a pressure cavity 17, the pressure cavity 17 of the flexible static ring expands to enable the flexible static ring to be in contact sealing with a corresponding movable ring through the friction part 16, when three flexible static rings are in contact sealing with the corresponding movable ring, a high-pressure medium fluid cavity in a turbine shell is divided into a first-stage cavity at the periphery of a flexible static ring I7, a second-stage cavity between a flexible static ring II 8 and the flexible static ring I7, and a third-stage cavity between a flexible static ring III 9 and the flexible static ring II 8. A pressure regulator with a first pressure regulating cavity 1801, a second pressure regulating cavity 1802 and a third pressure regulating cavity 1803 is arranged, the pressure cavity 17 of the first flexible static ring 7 is connected with the first-stage cavity through the first pressure regulating cavity 1801, the pressure cavity 17 of the second flexible static ring 8 is connected with the second-stage cavity through the second pressure regulating cavity 1802, and the pressure cavity 17 of the third flexible static ring 9 is connected with the third-stage cavity through the third pressure regulating cavity 1803.
The high-pressure medium fluid in the first-stage cavity passes through the first pressure regulating cavity 1801, the first pressure regulating cavity 1801 releases fluid pressure to enter the pressure cavity of the first flexible static ring 7, and the pressure cavity 17 of the first flexible static ring 7 expands, so that the first flexible static ring 7 and the first movable ring 11 are compressed to form a first-stage friction pair for sealing. The second-stage sealing of the flexible static ring II 8 and the movable ring II 12 is not started at first, and only when the second-stage cavity is pressurized by fluid leakage, the leaked fluid passes through the pressure regulating cavity II 1802, the pressure regulating cavity II 1802 releases the fluid pressure to enter the pressure cavity 17 of the flexible static ring II 8, and the flexible static ring II 8 is tightly pressed with the movable ring II 12 to form a second-stage friction pair for sealing. The third-stage sealing of the flexible static ring III 9 and the movable ring III 13 is not started at first, and the leaked fluid passes through the pressure regulating cavity III 1803 when the third-stage cavity is leaked with fluid to generate pressure, the pressure regulating cavity III 1803 releases the fluid pressure to enter the pressure cavity 17 of the flexible static ring III 9, and the flexible static ring III 9 is tightly pressed with the movable ring III 13 to form a third-stage friction pair for sealing.
The pressure regulating method of the pressure regulator comprises the following steps: a first spring 19 and a first plunger 20 are arranged in the first pressure regulating cavity 1801, the first spring 19 is abutted against one end of the first plunger 20, so that the first plunger 20 seals a communication port between the first pressure regulating cavity 1801 and the first-stage cavity, when the pressure reaches a certain degree, the first plunger 20 is pushed away, the communication port releases the fluid pressure to enter a pressure cavity 17 of the first flexible static ring 7, the first flexible static ring 7 expands, and the first flexible static ring 7 is compressed with the first movable ring 11; a second spring 21 and a second plunger 22 are arranged in the second pressure regulating cavity 1802, the second spring 21 is abutted against one end of the second plunger 22, so that the second plunger 22 seals a communication port between the second pressure regulating cavity 1802 and the second-stage cavity, when the pressure reaches a certain degree, the second plunger 22 is pushed away, the communication port releases the fluid pressure to enter a pressure cavity 17 of the second flexible static ring 8, the second flexible static ring 8 expands, and the second flexible static ring 8 is compressed with the second movable ring 12; and a spring III 26 and a plunger III 27 are arranged in the pressure regulating cavity III 1803, the spring III 26 is abutted against one end of the plunger III 27, so that the plunger III 27 seals a communication port between the pressure regulating cavity III 1803 and a third-stage cavity, when the pressure reaches a certain degree, the plunger III 27 is pushed away, the communication port releases the fluid pressure to enter the pressure cavity 17 of the flexible static ring III 9, the flexible static ring III 9 expands, and the flexible static ring III 9 is tightly pressed with the movable ring III 13.
The turbine shaft end sealing method further comprises the following steps: the shell of the steam turbine comprises an end cover 4, the end cover 4 is matched with a rotating shaft 1 of the steam turbine to form fourth-stage sealing, and a plurality of annular sealing teeth 401 which are sequentially arranged are arranged on the inner surface of the end cover 4 matched with the rotating shaft 1.
In addition to the above preferred embodiments, the present invention has other embodiments, and various changes and modifications may be made by those skilled in the art without departing from the spirit of the invention, which is defined in the appended claims.

Claims (3)

1. A multi-end self-regulating and starting turbine shaft end sealing method is used for sealing a gap between a turbine shell and a rotating shaft, a high-pressure medium fluid cavity is arranged in the turbine shell, a low-pressure atmosphere side is arranged outside the turbine shell,
a static ring seat is fixedly arranged on a shell of the steam turbine, a flexible static ring I, a flexible static ring II and a flexible static ring III are fixedly arranged on the static ring seat, and the diameters of the flexible static ring I, the flexible static ring II and the flexible static ring III are sequentially reduced; the rotating shaft is fixedly provided with a moving ring seat, and the moving ring seat is fixedly provided with a moving ring I, a moving ring II and a moving ring III which correspond to the flexible static ring I, the flexible static ring II and the flexible static ring in a three-phase manner; each flexible stationary ring is provided with a friction part at the outer end, each flexible stationary ring is internally provided with a pressure cavity, the pressure cavity of the flexible stationary ring expands to enable the flexible stationary ring to be in contact seal with a corresponding movable ring through the friction parts, and when three flexible stationary rings are in contact seal with the corresponding movable rings, a high-pressure medium fluid cavity in a steam turbine shell is divided into: the first-stage cavity is arranged on the periphery of the first flexible static ring, the second-stage cavity is arranged between the second flexible static ring and the first flexible static ring, and the third-stage cavity is arranged between the third flexible static ring and the second flexible static ring; the pressure regulator is provided with a first pressure regulating cavity, a second pressure regulating cavity and a third pressure regulating cavity, the pressure cavity of the flexible static ring I is connected with the first-stage cavity through the first pressure regulating cavity, the pressure cavity of the flexible static ring II is connected with the second-stage cavity through the second pressure regulating cavity, and the pressure cavity of the flexible static ring III is connected with the third-stage cavity through the third pressure regulating cavity;
the high-pressure medium fluid in the first-stage cavity passes through the first pressure regulating cavity, the first pressure regulating cavity releases fluid pressure to enter the pressure cavity of the first flexible static ring, and the pressure cavity of the first flexible static ring expands, so that the first flexible static ring and the first movable ring are tightly pressed to form a first-stage friction pair for sealing; the second-stage sealing of the flexible static ring II and the movable ring II is not started at first, and only when the second-stage cavity is pressurized by fluid leakage, the leaked fluid passes through the pressure regulating cavity II, the pressure regulating cavity II releases the fluid pressure to enter the pressure cavity of the flexible static ring II, and the flexible static ring II is tightly pressed with the movable ring II to form a second-stage friction pair for sealing; the third-stage sealing of the flexible static ring III and the movable ring III is not started at first, and the leaked fluid passes through the pressure regulating cavity III when the third-stage cavity is pressurized by fluid leakage, the pressure of the fluid is released by the pressure regulating cavity III and enters the pressure cavity of the flexible static ring III, and the flexible static ring III is tightly pressed with the movable ring III to form a third-stage friction pair for sealing.
2. The multi-end self-regulating and starting steam turbine shaft end sealing method according to claim 1, wherein the pressure regulator comprises the following steps: a first spring and a first plunger are arranged in the first pressure regulating cavity, the first spring is abutted against one end of the first plunger, so that the first plunger seals a communication port between the first pressure regulating cavity and the first-stage cavity, when the pressure reaches a certain degree, the first plunger is pushed away, the communication port releases fluid pressure to enter a pressure cavity of the first flexible static ring, the first flexible static ring expands, and the first flexible static ring is compressed with the first movable ring; a second spring and a second plunger are arranged in the pressure regulating cavity II, the second spring is abutted against one end of the second plunger, so that the second plunger seals a communication port between the pressure regulating cavity II and the second-stage cavity, when the pressure reaches a certain degree, the second plunger is pushed away, the communication port releases the fluid pressure to enter a pressure cavity of the second flexible stationary ring, the second flexible stationary ring expands, and the second flexible stationary ring is tightly pressed with the second movable ring; the pressure regulating cavity III is internally provided with a spring III and a plunger III, the spring III is abutted to one end of the plunger III, so that the plunger III seals a communication port between the pressure regulating cavity III and a third-stage cavity, when the pressure reaches a certain degree, the plunger III is pushed away, the communication port releases fluid pressure to enter a pressure cavity of the flexible static ring III, the flexible static ring III expands, and the flexible static ring III is tightly pressed with the movable ring III.
3. The multi-port self-regulating enabled turbine shaft end sealing method of claim 1 further comprising: the shell of the steam turbine comprises an end cover, the end cover is matched with a rotating shaft of the steam turbine to form fourth-stage seal, and a plurality of annular seal teeth which are sequentially arranged are arranged on the inner surface of the end cover matched with the rotating shaft.
CN202110155736.6A 2021-02-04 2021-02-04 Multi-end-face self-regulation and starting steam turbine shaft end sealing method Active CN112923060B (en)

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DE2925244C2 (en) * 1979-06-22 1982-09-30 Howaldtswerke-Deutsche Werft Ag Hamburg Und Kiel, 2300 Kiel Sealing arrangement for stern tube systems
CN102869907B (en) * 2010-04-30 2016-05-04 西门子公司 There is the device of shaft seal
CN203784293U (en) * 2014-01-26 2014-08-20 清华大学 Mechanical sealing device
US10415707B2 (en) * 2016-06-30 2019-09-17 General Electric Company Face seal assembly and an associated method thereof
EP3660324A4 (en) * 2017-07-26 2021-04-14 Ebara Corporation Pump and sealing system
CN107504189B (en) * 2017-08-28 2018-11-13 浙江工业大学 A kind of liquid machine sealing device suitable for transformation environment
CN110440005B (en) * 2019-08-29 2024-05-03 浙江工业大学 Mechanical sealing device with adjustable and controllable local film thickness between sealing end surfaces
CN112303239B (en) * 2020-10-28 2022-10-04 中国计量大学 Active dynamic pressure type air film end face sealing device and intelligent control method thereof

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