CN111828100A - Serial dry gas sealing device for industrial steam turbine - Google Patents
Serial dry gas sealing device for industrial steam turbine Download PDFInfo
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- CN111828100A CN111828100A CN202010810301.6A CN202010810301A CN111828100A CN 111828100 A CN111828100 A CN 111828100A CN 202010810301 A CN202010810301 A CN 202010810301A CN 111828100 A CN111828100 A CN 111828100A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/02—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type
- F01D11/04—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type using sealing fluid, e.g. steam
Abstract
A series dry gas sealing device for an industrial steam turbine comprises two groups of rotary sealing components and two groups of static sealing components which are arranged in series. Each rotary seal assembly includes a rotating ring and a rotating ring seat disposed on a journal. Each group of static sealing components comprises a sealing sleeve fixed in the casing, and also comprises a static ring and a corrugated pipe which are coaxially arranged with the shaft sleeve. Under the action of self elasticity, the inner end face of the corrugated pipe is pressed against the outer end face of the static ring to form a contact sealing structure. The static ring is arranged between the corrugated pipe and the dynamic ring and is connected with the sealing sleeve in a floating mode through the stop pin. When the movable ring rotates along with the shaft of the steam turbine, the outer side end face of the movable ring and the inner side end face of the static ring form a non-contact air film lubrication state. Because the dynamic ring and the static ring have self-adjusting capacity, stable air film lubrication non-contact sealing is formed between the dynamic ring and the static ring, so that high-pressure steam is sealed in the turbine, zero-leakage sealing of the steam in the turbine is realized, and the energy conversion efficiency of the steam turbine is greatly improved.
Description
Technical Field
The invention relates to the technical field of mechanical sealing, in particular to a series dry gas sealing device for an industrial steam turbine.
Background
A steam turbine is one of the main equipments of a steam power plant, and is a rotary power machine that converts the energy of steam into mechanical work. The working principle of the steam turbine is that steam with certain pressure and temperature enters the steam turbine, the steam rapidly expands in a nozzle to obtain high flow speed, and then the steam flowing at high speed drives a rotor blade of the steam turbine to rotate and do work, so that the process of obtaining mechanical energy is achieved. The steam turbine mainly comprises a rotating part, a fixed part and a control part.
The industrial steam turbine is a motive power device using steam as impulse, and is mainly used in industrial enterprises of chemical industry, petroleum, mining, metallurgy, paper making, textile, sugar making and the like. Industrial turbines drive various pumps, fans, compressors, presses or drive generators, thereby producing low cost power and electricity. In advanced industrial countries, primary energy has been fully utilized since steam turbines have been used industrially. The small-sized heat (electricity) power cogeneration (small back press) can fully utilize waste materials, waste gases and waste heat to produce steam, or utilize rich steam and steam pressure difference, and then convert the rich steam into mechanical energy to directly drive mechanical equipment to do work through a power turbine, and can realize variable-speed operation of the mechanical equipment through regulating the rotating speed of the turbine. Because the energy conversion link is reduced, the energy conversion efficiency is increased, and the expensive industrial electricity is saved, the purpose of saving energy and improving efficiency can be achieved by using an industrial steam turbine as a motive power device in production. In addition, the steam extraction and exhaust of the industrial steam turbine can also be used for industrial production processes or external supply of enterprises and public institutions, so that the gradient utilization of energy is realized, the method is one of effective measures for energy conservation and consumption reduction of the enterprises and public institutions, and has the advantages of low investment, quick response and remarkable comprehensive economic benefit.
The current industrial steam turbine usually adopts a comb type labyrinth seal or a carbon ring seal form at the shaft end because of high pressure and high temperature of working medium. Because labyrinth seal and carbon ring seal all belong to radial non-contact seal, in order to ensure to avoid appearing main shaft or axle sleeve and sealed position collision and rub in whole working process, its radial seal clearance is all bigger (static or dynamic), leads to the leakage volume of axial steam to be great. In particular, the back pressure turbine has higher sealing cavity pressure and larger shaft end sealing leakage amount. The leakage of steam causes energy loss, and the leaked steam needs to be cooled by circulating cooling water, so that the consumption of the cooling water is large. According to statistics, for a medium-sized steam turbine set, the annual leakage amount of steam, the consumption amount of cooling water and subsequent operation and maintenance costs thereof are reduced to the operation cost of more than one million yuan.
Different from the dynamic and static sealing of general machinery, the sealing of the shaft end of the industrial steam turbine is influenced by a plurality of factors and the situation is complex. Under the influence of high temperature and high pressure of steam in the steam turbine and factors such as thermal expansion, jumping, flexible deformation and the like when a shaft of the steam turbine rotates at high speed, the problem of shaft end leakage of the industrial steam turbine is a technical problem which is wanted to be solved and cannot be solved in the industry for a long time. From the perspective of energy conservation and efficiency improvement, a novel sealing device which is high in reliability and can obviously reduce the leakage amount of shaft end sealing is urgently needed.
Disclosure of Invention
In order to overcome the defects in the background art, the invention discloses a serial dry gas sealing device for an industrial steam turbine, which adopts the following technical scheme:
a serial dry gas sealing device for an industrial steam turbine is axially arranged between a casing and a bearing box and radially arranged between the casing and a journal of a steam turbine shaft, and comprises two groups of rotary sealing components and two groups of static sealing components which are arranged in series;
each group of rotary sealing components comprises a movable ring arranged on the shaft neck, and a movable ring seat which is used for sealing and supporting the end surface of the inner side of the movable ring and driving the movable ring to rotate along with the shaft of the steam turbine; a plurality of pneumatic pressure grooves distributed circumferentially are arranged on the outer side end surface of the movable ring;
each group of static sealing components comprises a sealing sleeve which is fixed in the casing and is in sealing connection with the casing, and also comprises a static ring and a corrugated pipe which are coaxially arranged with the shaft sleeve; the outer side end face of the corrugated pipe is in sealing connection with the sealing sleeve; the static ring is arranged between the corrugated pipe and the dynamic ring and is in floating connection with the sealing sleeve through a stop pin; under the action of self elasticity, the end surface of the inner side of the corrugated pipe is pressed on the end surface of the outer side of the static ring to form a contact sealing structure; the end face of the inner side of the static ring is opposite to the end face of the outer side of the dynamic ring, and when the dynamic ring rotates along with a shaft of the steam turbine, the end face of the outer side of the dynamic ring and the end face of the inner side of the static ring form a non-contact dry gas sealing structure;
the group of rotary sealing assemblies and the static sealing assemblies close to the inner side of the machine form a primary sealing structure, and the group of rotary sealing assemblies and the static sealing assemblies close to the outer side of the machine form a secondary sealing structure; the secondary sealing structure is used for carrying out secondary sealing on the steam in the machine leaked by the primary sealing structure.
As a preferred technical scheme, the static sealing assembly further comprises a damping sleeve for radially limiting the static ring and the corrugated pipe, an outer sleeve surface of the damping sleeve is in contact connection with an inner sleeve surface of the sealing sleeve through a centering ring spring, and the inner sleeve surface is in contact connection with outer surfaces of the static ring and the corrugated pipe respectively.
As a preferred technical solution, a first shaft sleeve and a second shaft sleeve are arranged on the shaft neck; the movable ring seat close to the inner side of the machine is connected to the inner side end of the first shaft sleeve and abuts against the shaft shoulder part of the inner side of the shaft neck; a compression sleeve is connected to the outer side end of the first shaft sleeve, and a flexible graphite ring is arranged between the compression sleeve and the first shaft sleeve; the second shaft sleeve is pressed against the outer side end of the pressing sleeve, and the outer side end of the second shaft sleeve is backed up by a main shaft nut screwed on the shaft neck; one part of the inner side end of the second shaft sleeve is sleeved on the first shaft sleeve and extends to the outer side end face of the movable ring in the secondary sealing structure for axially limiting the movable ring; the movable ring seat close to the outer side of the machine is connected to the first shaft sleeve through a key, and one part of the inner side end of the movable ring seat extends to the outer side end face of the movable ring in the primary sealing structure and is used for axially limiting the movable ring.
As a preferred technical scheme, a centering ring spring is sleeved on the first shaft sleeve; the centering coil spring is contacted with the inner ring surface of the moving ring, and the moving ring has a certain floating amount; the movable ring seat is provided with a supporting surface corresponding to the end surface of the inner side of the movable ring, the supporting surface is provided with a flexible graphite ring for sealing the end surface of the inner side of the movable ring, and the movable ring seat is also provided with a transmission pin in the axial direction; the rotating ring is provided with a pin shaft hole corresponding to the transmission pin, the diameter of the pin shaft hole is larger than that of the transmission pin, and the rotating ring seat drives the rotating ring to rotate along with the shaft of the steam turbine through the transmission pin.
As a preferred technical scheme, an external comb labyrinth seal structure is arranged between a main shaft nut and a seal sleeve; the sealing sleeve is provided with a vent cavity between the comb-shaped labyrinth sealing structure and the secondary sealing structure outside the machine, and the vent cavity is communicated with the atmosphere through a vent hole.
As a preferred technical scheme, an air isolating cavity is arranged between the labyrinth sleeve and the spindle nut, the air isolating cavity is arranged in the middle of the comb-shaped labyrinth sealing structure outside the machine, and the air isolating cavity is communicated with the outside through a pipeline.
As a preferred technical scheme, the inner and outer sleeve surfaces of the sealing sleeve are all multi-step surfaces; the outer sleeve surface of the sealing sleeve is in sealing connection with the casing through a plurality of sealing rings, and the inner sleeve surface of the sealing sleeve is in sealing connection with the outer sleeve surface of the labyrinth sleeve through the sealing rings and is in sealing connection with the outer side end surface of the corrugated pipe through a flexible graphite ring.
As a preferred technical scheme, a main sealing cavity for preventing steam in the machine from entering is arranged on the inner side of a sealing sleeve of the machine shell, and main sealing gas is introduced into the main sealing cavity; the main seal gas is an internal medium meeting a certain quality standard or external steam after filtration treatment, and the pressure of the main seal gas is greater than that of the internal steam.
As a preferred technical scheme, a leakage gas recovery cavity is arranged between the primary sealing structure and the primary sealing structure of the machine shell, and the leakage gas recovery cavity is communicated with an external leakage gas recovery device through a pipeline.
As a preferred technical scheme, the pneumatic pressure groove is a one-way groove or a two-way groove; the depth of the one-way groove is 3-20 μm, and the width of the dam area of the pneumatic groove pressing is 0.25-0.75 times of the width of the sealing surface; the movable ring is made of silicon carbide, silicon nitride or hard alloy; the static ring is made of graphite or silicon carbide with a diamond-like film plated on the surface.
Due to the adoption of the technical scheme, compared with the background technology, the invention has the following beneficial effects:
the invention realizes the static seal between the casing and the sealing sleeve, and between the sealing sleeve and the corrugated pipe, and realizes the contact seal between the corrugated pipe and the static ring, and the air film lubrication non-contact seal between the dynamic ring and the static ring. The two-stage series connection sealing structure seals high-pressure steam in the turbine, so that energy consumption is reduced, and the energy conversion efficiency of the industrial steam turbine is improved.
The movable ring and the static ring have self-adjusting capacity, and when the shaft of the steam turbine has the phenomena of thermal expansion, jumping, flexible deformation and the like, a stable air film can be formed between the movable ring and the static ring all the time, so that the dry gas sealing structure can work reliably for a long time.
The invention adopts double dry gas sealing structures, under the same working condition, the steam leakage amount of each dry gas sealing structure is only one tenth to one hundredth of the existing sealing structure, and the double dry gas sealing structure basically realizes zero leakage sealing. Because steam no longer leaks, therefore also need not to set up extra leakage steam cooling device for the subsequent operation maintenance cost of industrial steam turbine reduces by a wide margin, can save nearly million yuan of operation cost annually.
The dry gas seal is originally developed to solve the problem of shaft end sealing of a high-speed centrifugal compressor, but cannot be applied in the industry of steam turbines due to various factors, wherein one important reason is that the industrial steam turbines cannot ensure that a stable dry gas seal is formed between a moving ring and a static ring under complex working conditions. The invention stably realizes dry gas sealing between the dynamic ring and the static ring through long-term practice verification, solves the technical problem which is always solved but can not be solved in the industry, and has great significance! In addition, the invention has obvious effect of energy saving and efficiency improvement and great economic value.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a schematic structural view of a pneumatic indent.
In the figure: 1. a journal; 2. a housing; 3. a first bushing; 4. a second shaft sleeve; 5. a moving ring; 51. pneumatic groove pressing; 6. a movable ring seat; 7. a spindle nut; 8. a bellows; 9. a stationary ring; 10. sealing sleeves; 11. a damping sleeve; 12. a centering coil spring; 13. a labyrinth sleeve; 14. a drive pin; 15. a retaining pin; 16. a flexible graphite ring; 17. the comb-shaped labyrinth sealing structure in the machine; 18. an external comb labyrinth seal structure; 19. a primary seal cavity; 20. an air insulation cavity; 21. a leakage gas recovery chamber; 22. placing the cavity; 23. and (4) a compression sleeve.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
It should be noted that in the description of the present invention, the terms "inside", "outside", etc. indicating directions or positional relationships are based on relative indicating directions or positional relationships centering on the main body of the industrial steam turbine, which are merely for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
A series dry gas sealing device for an industrial steam turbine is axially arranged between a casing 2 and a bearing box (not shown in the figure) and radially arranged between the casing 2 and a shaft neck 1 of a steam turbine shaft as shown in figure 1, and comprises two groups of rotary sealing assemblies and two groups of static sealing assemblies which are arranged in series, wherein one group of rotary sealing assemblies and the static sealing assemblies close to the inner side of the steam turbine form a primary sealing structure, and one group of rotary sealing assemblies and the static sealing assemblies close to the outer side of the steam turbine form a secondary sealing structure. The primary sealing structure and the secondary sealing structure are combined in series to form the main sealing structure.
Each group of rotary sealing components comprises a movable ring 5 arranged on the shaft neck 1 and a movable ring seat 6 which is used for sealing and supporting the end surface of the inner side of the movable ring 5 and driving the movable ring 5 to rotate along with the shaft of the steam turbine. Specifically, a first sleeve 3 and a second sleeve 4 are provided on the journal 1. The movable ring seat 6 close to the inner side of the machine is connected to the inner side end of the first shaft sleeve 3 and abuts against the inner shaft shoulder part of the shaft neck 1. A pressing sleeve 23 is connected to the outer end of the first sleeve 3. The second sleeve 4 is pressed against the outer end of the pressing sleeve 23 and its outer end is backed up by a spindle nut 7 screwed onto the journal 1, so that the first and second sleeves 3, 4 are fixed on the journal 1 and rotate together with the turbine shaft. In order to limit the outward axial movement of the movable ring 5, a part of the inner end of the second shaft sleeve 4 is sleeved on the first shaft sleeve 3 and extends to the outer end face of the movable ring 5 in the secondary sealing structure, so as to limit the movable ring 5 in the axial direction, but not limit the floating of the movable ring 5. Similarly, the movable ring seat 6 near the outer side of the machine is connected to the first shaft sleeve 3 through a key, and a part of the inner side end of the movable ring seat extends to the outer side end face of the movable ring 5 in the primary sealing structure, so as to limit the movable ring 5 in the axial direction, but not limit the floating of the movable ring 5. In order to prevent leakage of the internal steam from the gap between the shaft journal 1 and the first shaft sleeve 3, a flexible graphite ring 16 is arranged between the pressure sleeve 23 and the first shaft sleeve 3. The flexible graphite ring 16 not only has good sealing performance, but also has high temperature resistance. The movable ring seat 6 is provided with a supporting surface corresponding to the end surface of the inner side of the movable ring 5, the supporting surface is provided with two flexible graphite rings 16 for sealing the end surface of the inner side of the movable ring 5, and the supporting surface is also provided with a transmission pin 14 in the axial direction. The rotating ring 5 is provided with a pin shaft hole corresponding to the driving pin 14, and the driving pin 14 is connected with the pin shaft hole of the rotating ring 5 in a floating manner. When the rotating ring seat 6 rotates along with the steam turbine shaft, the rotating ring seat 6 transmits a rotating torque to the rotating ring 5 through the transmission pin 14, so that the rotating ring 5 rotates along with the steam turbine shaft.
Each group of static sealing components comprises a sealing sleeve 10 which is fixed in the inner cavity of the machine shell 2 and is connected with the inner cavity of the machine shell 2 in a sealing way. The gland 10 has a longer axial dimension due to the primary seal structure extending through the gland 10. In order to reduce the processing difficulty and facilitate the assembly and maintenance, the sealing sleeve 10 is formed by connecting three parts. The inner and outer sleeve surfaces of the sealing sleeve 10 are both of a multi-step surface structure, and the outer sleeve surface of the sealing sleeve 10 is in sealing connection with the casing 2 through a plurality of sealing rings, so that sealing between the sealing sleeve 10 and the casing 2 is realized.
Each set of stationary seal assemblies further comprises a stationary ring 9 and a bellows 8 arranged coaxially with the first bushing 3. The corrugated pipe 8 is a high-temperature resistant stainless steel corrugated pipe 8, is resistant to high-temperature corrosion and has good elasticity. The outer end face of the corrugated pipe 8 is fixed on the sealing sleeve 10 through a bolt, and is in sealing connection with the inner sleeve face of the sealing sleeve 10 through a flexible graphite ring 16. The static ring 9 is arranged between the corrugated pipe 8 and the dynamic ring 5 and is in floating connection with the sealing sleeve 10 through a stop pin 15. Since the bellows 8 is elastic, it has a certain axial elasticity when compressed. Under the action of self axial elasticity, the inner end face of the corrugated pipe 8 is pressed against the outer end face of the static ring 9, and a contact sealing structure between the corrugated pipe 8 and the static ring 9 is formed. The inner side end face of the static ring 9 is opposite to the outer side end face of the movable ring 5, and under the action of the axial elasticity of the corrugated pipe 8, a certain contact pressure is kept between the static ring 9 and the movable ring 5.
The outer side end face of the movable ring 5 is provided with a plurality of circumferentially distributed pneumatic pressure grooves 51, and the pneumatic pressure grooves 51 are opened at one side of high-pressure steam in the machine. The pneumatic groove 51 may be a groove type rotating in one direction or a groove type rotating in two directions. Can be a unidirectional arc groove, a spiral groove, a triangular groove, or a bidirectional groove, such as a hammer-shaped bidirectional groove. In this embodiment, the high-pressure steam in the steam generator is located on the outer annular surface side of the rotating ring 5, and the pneumatic pressure groove 51 is a one-way spiral groove. As shown in fig. 2, the unidirectional spiral groove has the same rotational direction as the turbine shaft, and extends spirally from the inside of the outer end surface of the rotor ring 5 in the outer radial direction and opens into the outer annular surface of the rotor ring 5. The cross-sectional area of the unidirectional helical groove increases gradually along the direction of helical extension. The depth of the one-way spiral groove is 15 μm, and the width of the dam area of the pneumatic pressure groove 51 is 0.7 times of the width of the outer side end face of the movable ring 5. When the moving ring 5 rotates along with the shaft of the steam turbine, high-pressure steam enters the one-way spiral groove and generates a fluid dynamic pressure effect, and the high-pressure steam at the outer ring surface is pumped inwards, so that a layer of micron-order air film is formed between the outer side end surface of the moving ring 5 and the inner side end surface of the static ring 9, and the sealing surface between the moving ring 5 and the static ring 9 is lubricated and isolated. Because the rotating speed of the shaft of the steam turbine is very high, the rigidity of the air film is very high, the opening force formed by the air film and the axial elastic force of the corrugated pipe 8 reach balance, and therefore non-contact operation is achieved, and sealing of steam in the steam turbine is achieved. The steam quantity leaked through the dry gas sealing structure is only one tenth to one hundredth of that of a comb-tooth type labyrinth seal or a carbon ring seal under the same working condition. The device is provided with two dry gas sealing structures which are connected in series in the main sealing structure, and the secondary sealing structure positioned at the outer side seals the steam leaked by the primary sealing structure positioned at the inner side again, so that zero-leakage sealing of the steam in the device is basically realized. Because the steam is not leaked any more, an additional leakage steam cooling device is not needed, and the subsequent operation and maintenance cost of the industrial steam turbine is greatly reduced.
When the shaft of the steam turbine rotates at high speed, the phenomena of thermal expansion, jumping, flexible deformation and the like inevitably occur at the journal 1 part. And the dry gas sealing structure requires that the sealing surface between the dynamic ring 5 and the static ring 9 has strict parallel relation. Thus, at least one of the movable ring 5 and the stationary ring 9 is ensured to have a self-adjusting capability. For this purpose, a centering coil spring 12 is sleeved on the first shaft sleeve 3, and the centering coil spring 12 is contacted with the inner ring surface of the movable ring 5; the diameter of the pin shaft hole is larger than that of the driving pin 14, so that the driving pin 14 is prevented from limiting the floating of the movable ring 5; a certain gap is reserved between the movable ring seat 6 and the outer ring surface of the movable ring 5. These measures provide a certain floating amount for the movable ring 5, and realize the self-adjustment of the movable ring 5.
In order to provide the static ring 9 with the freedom of self-adjustment following the movable ring 5, a long groove with a radial opening is arranged on the outer ring surface of the static ring 9, the static ring 9 is in clearance connection with a stop pin 15 through the long groove, the rotation of the static ring 9 is prevented, but the floating of the static ring 9 is not limited. Bellows 8 applys certain axial force to quiet ring 9, guarantees that the sealed face of quiet ring 9 does not deviate from the sealed face of rotating ring 5, and bellows 8 self has certain universal flexibility moreover, guarantees that bellows 8 carries out the sealed face of perpendicular to rotating ring 5 all the time to the axial force that quiet ring 9 was applyed, makes quiet ring 9 have the degree of freedom that follows rotating ring 5 and carry out the self-regulation all the time. Thus, when the phenomena of thermal expansion, jumping, flexible deformation and the like occur at the position of the shaft neck 1, a layer of parallel air film is always formed between the movable ring 5 and the static ring 9, and the normal work of the dry air sealing structure can be ensured.
When the steam turbine works, the movable ring 5 rotates at a high speed along with the shaft of the steam turbine, so that the material has high requirements on the strength; the high-temperature high-pressure steam generator works in a high-temperature high-pressure steam environment for a long time, so that the high-temperature high-pressure steam generator has high requirements on the physical properties of the materials of the moving environment 5 and the static environment 9; furthermore, the sealing surfaces between the rotating ring 5 and the stationary ring 9 are subject to slight contact wear during starting and stopping, so that the surface tribological properties of the materials of the rotating ring 5 and the stationary ring 9 are also highly required. Therefore, the moving ring 5 can be made of high-hardness and high-wear-resistance materials such as silicon carbide, silicon nitride or hard alloy materials with high strength, good tribological characteristics and relatively high hardness, and can also be made of stainless steel materials as a substrate, and a high-hardness wear-resistance coating is sprayed or surfacing-welded on the surface of the substrate. The stationary ring 9 may be made of graphite having a good self-lubricating property, or silicon carbide with a diamond-like carbon film (DLC) plated on the surface thereof. With the DLC coating technique, the surface tribological properties of the hard-to-hard friction pair pairing can be improved. The service life of the dynamic ring 5 and the static ring 9 is prolonged, and the maintenance cost of the steam turbine can be greatly reduced.
Because the disturbance of built-in steam air current can cause the tremble to quiet ring 9, bellows 8, makes quiet ring 9, 8 eccentric unstability of bellows even, further improves technical scheme, quiet seal assembly still includes carries out radial spacing damping sleeve 11 to quiet ring 9, bellows 8, and damping sleeve 11 adopts high temperature resistant metal material to make, and in this embodiment, damping sleeve 13's material is the stainless steel. The outer ring surface of the damping ring sleeve is in contact connection with the inner ring surface of the sealing sleeve 10 through a two-stage centering ring spring 12, and the inner ring surface is in contact connection with the outer surfaces of the static ring 9 and the corrugated pipe 8 respectively. It should be noted here that the damping bushing is not fixed in the inner sleeve surface of the sealing sleeve 10, but is connected in contact with the inner sleeve surface of the sealing sleeve 10 by means of a two-stage centering coil spring 12. The two-stage centering coil spring 12 allows the damping sleeve 11 to have a certain axial oscillation amount, and therefore, the damping sleeve 11 does not prevent the stationary ring 9 from always having a degree of freedom to self-adjust following the moving ring 5, although it radially restricts the stationary ring 9 and the bellows 8.
In conclusion, the device realizes the sealing of the casing 2 and the sealing sleeve 10; the sealing of the sealing sleeve 10 and the corrugated pipes 8 at the inner side and the outer side is realized; the contact sealing between the corrugated pipes 8 at the two sides and the static ring 9 at the same side is realized; a steam lubrication non-contact sealing state is formed between the inner side moving ring 5 and the outer side moving ring 9. The two-stage series connection sealing structure seals high-pressure steam in the turbine, so that energy consumption is reduced, and the energy conversion efficiency of the industrial steam turbine is improved.
The cleanliness requirement of the dry gas seal on the gas at the high-pressure end is high, otherwise, the dirty gas at the high-pressure end can pollute the friction pair end face of the dry gas seal, and the bellows 8 loses elasticity and compensation capacity, so that the seal fails prematurely. For this purpose, the casing 2 is provided with a main seal chamber 19 for preventing the entry of the steam inside the casing 10, and a main seal gas is introduced into the main seal chamber 19. It should be noted that the main seal chamber 19 is located between the primary seal structure and the comb-like labyrinth seal structure 17 in the machine. The comb-shaped labyrinth seal structure 17 in the turbine is a seal structure of the existing turbine, and the seal structure has large steam leakage amount but is not influenced by thermal expansion. The device only utilizes the prior structure to carry out primary sealing on the steam in the machine.
The main seal gas can be high-pressure high-temperature steam led out from the inlet of the steam turbine or externally led steam with pressure and temperature meeting requirements, and enters the main seal cavity 19 through a pipeline after being properly cooled, decompressed and filtered. In this case, the pressure of the main seal gas is required to be higher than the steam pressure in the machine, and the main seal gas returns to the machine through the comb-shaped labyrinth seal structure 17 in the machine, so that the dirty steam in the machine, which is not filtered, is prevented from polluting the dry gas seal structure, and the heat generated by the dry gas seal structure is taken away. If the cleanliness of the steam medium in the steam turbine meets a certain quality standard, the steam medium can also be directly used as main seal gas to enter the main seal cavity 19 through the comb-shaped labyrinth seal structure 17 in the steam turbine, and at the moment, an external pipeline of the main seal cavity 19 is in a closed state.
In order to prevent the lubricating oil gas in the bearing box (outside the spindle nut 7, not shown in the figure) from polluting the dry gas sealing structure through diffusion, a labyrinth sleeve 13 is arranged between the spindle nut 7 and the sealing sleeve 10, and the outer sleeve surface of the labyrinth sleeve 13 is connected with the inner sleeve surface of the sealing sleeve 10 through a sealing ring. A plurality of comb-shaped inner ring teeth are arranged on the labyrinth sleeve 13, and an external comb-shaped labyrinth sealing structure 18 is formed by the labyrinth sleeve and the spindle nut 7. The sealing sleeve 10 is provided with a venting cavity 22 between the outer comb-shaped labyrinth sealing structure 18 and the secondary sealing structure, and the venting cavity 22 is communicated with the atmosphere through a vent. Therefore, the outer comb-shaped labyrinth seal structure 18 can seal most of the lubricating oil gas, and a small amount of lubricating oil gas leaked from the outer comb-shaped labyrinth seal structure 18 is discharged through the vent, so that the pollution of the lubricating oil gas to the dry gas seal structure is avoided. Similarly, a very small amount of vapor leaking from the secondary seal structure is vented through the vent after entering the low pressure chamber. Meanwhile, an air-isolating cavity 20 is arranged between the labyrinth sleeve 13 and the spindle nut 7, the air-isolating cavity 20 is arranged in the middle of the comb-shaped labyrinth seal structure 18 outside the machine, and the air-isolating cavity 20 is communicated with the outside through a pipeline. The isolation gas is nitrogen or instrument air, and after the nitrogen enters the isolation cavity 20, the nitrogen blocks the lubricating oil gas entering the comb-shaped labyrinth sealing structure 18 outside the machine. Excess nitrogen enters the low pressure chamber and is vented through a vent. In addition, the isolating gas can also cool the secondary sealing structure.
In order to recover the steam leaked from the primary sealing structure, a leaked gas recovery cavity 21 is arranged between the primary sealing structure and the primary sealing structure of the machine shell 2, the leaked gas recovery cavity 21 is communicated with an external leaked gas recovery device through a pipeline, and the leaked steam is returned to the machine for reuse.
The present invention is not described in detail in the prior art. Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. The utility model provides a serial-type dry gas sealing device for industrial steam turbine, axial setting is between casing and bearing box, radially between casing and the journal of steam turbine axle, characterized by: the sealing device comprises two groups of rotary sealing components and two groups of static sealing components which are arranged in series;
each group of rotary sealing components comprises a movable ring arranged on the shaft neck, and a movable ring seat which is used for sealing and supporting the end surface of the inner side of the movable ring and driving the movable ring to rotate along with the shaft of the steam turbine; a plurality of pneumatic pressure grooves distributed circumferentially are arranged on the outer side end surface of the movable ring;
each group of static sealing components comprises a sealing sleeve which is fixed in the casing and is in sealing connection with the casing, and also comprises a static ring and a corrugated pipe which are coaxially arranged with the shaft sleeve; the outer side end face of the corrugated pipe is in sealing connection with the sealing sleeve; the static ring is arranged between the corrugated pipe and the dynamic ring and is in floating connection with the sealing sleeve through a stop pin; under the action of self elasticity, the end surface of the inner side of the corrugated pipe is pressed on the end surface of the outer side of the static ring to form a contact sealing structure; the end face of the inner side of the static ring is opposite to the end face of the outer side of the dynamic ring, and when the dynamic ring rotates along with a shaft of the steam turbine, the end face of the outer side of the dynamic ring and the end face of the inner side of the static ring form a non-contact dry gas sealing structure;
the group of rotary sealing assemblies and the static sealing assemblies close to the inner side of the machine form a primary sealing structure, and the group of rotary sealing assemblies and the static sealing assemblies close to the outer side of the machine form a secondary sealing structure; the secondary sealing structure is used for carrying out secondary sealing on the steam in the machine leaked by the primary sealing structure.
2. The tandem dry gas seal device for an industrial steam turbine according to claim 1, wherein: the static sealing assembly further comprises a damping sleeve for radially limiting the static ring and the corrugated pipe, the outer sleeve surface of the damping sleeve is in contact connection with the inner sleeve surface of the sealing sleeve through a centering ring spring, and the inner sleeve surface is in contact connection with the outer surfaces of the static ring and the corrugated pipe respectively.
3. The tandem dry gas seal device for an industrial steam turbine according to claim 1 or 2, wherein: a first shaft sleeve and a second shaft sleeve are arranged on the shaft neck; the movable ring seat close to the inner side of the machine is connected to the inner side end of the first shaft sleeve and abuts against the shaft shoulder part of the inner side of the shaft neck; a compression sleeve is connected to the outer side end of the first shaft sleeve, and a flexible graphite ring is arranged between the compression sleeve and the first shaft sleeve; the second shaft sleeve is pressed against the outer side end of the pressing sleeve, and the outer side end of the second shaft sleeve is backed up by a main shaft nut screwed on the shaft neck; one part of the inner side end of the second shaft sleeve is sleeved on the first shaft sleeve and extends to the outer side end face of the movable ring in the secondary sealing structure for axially limiting the movable ring; the movable ring seat close to the outer side of the machine is connected to the first shaft sleeve through a key, and one part of the inner side end of the movable ring seat extends to the outer side end face of the movable ring in the primary sealing structure and is used for axially limiting the movable ring.
4. The tandem dry gas seal device for an industrial steam turbine according to claim 3, wherein: a centering ring spring is sleeved on the first shaft sleeve; the centering coil spring is contacted with the inner ring surface of the moving ring, and the moving ring has a certain floating amount; the movable ring seat is provided with a supporting surface corresponding to the end surface of the inner side of the movable ring, the supporting surface is provided with a flexible graphite ring for sealing the end surface of the inner side of the movable ring, and the movable ring seat is also provided with a transmission pin in the axial direction; the rotating ring is provided with a pin shaft hole corresponding to the transmission pin, the diameter of the pin shaft hole is larger than that of the transmission pin, and the rotating ring seat drives the rotating ring to rotate along with the shaft of the steam turbine through the transmission pin.
5. The tandem dry gas seal device for an industrial steam turbine according to claim 3, wherein: an external comb labyrinth seal structure is arranged between the main shaft nut and the seal sleeve; the sealing sleeve is provided with a vent cavity between the comb-shaped labyrinth sealing structure and the secondary sealing structure outside the machine, and the vent cavity is communicated with the atmosphere through a vent hole.
6. The tandem dry gas seal device for an industrial steam turbine according to claim 5, wherein: an air isolating cavity is arranged between the labyrinth sleeve and the spindle nut, the air isolating cavity is arranged in the middle of the comb-shaped labyrinth sealing structure outside the machine, and the air isolating cavity is communicated with external isolated air through a pipeline.
7. The tandem dry gas seal device for an industrial steam turbine according to claim 5 or 6, wherein: the inner and outer sleeve surfaces of the sealing sleeve are multi-step surfaces; the outer sleeve surface of the sealing sleeve is in sealing connection with the casing through a plurality of sealing rings, and the inner sleeve surface of the sealing sleeve is in sealing connection with the outer sleeve surface of the labyrinth sleeve through the sealing rings and is in sealing connection with the outer side end surface of the corrugated pipe through a flexible graphite ring.
8. The tandem dry gas seal device for an industrial steam turbine according to claim 1, 5 or 6, wherein: the inner side of the sealing sleeve of the shell is provided with a main sealing cavity for preventing steam in the shell from entering, and main sealing gas is introduced into the main sealing cavity; the main seal gas is an internal medium meeting a certain quality standard or external steam after filtration treatment, and the pressure of the main seal gas is greater than that of the internal steam.
9. The tandem dry gas seal device for an industrial steam turbine according to claim 8, wherein: the casing is provided with a leaked gas recovery cavity between the first-stage sealing structure and the second-stage sealing structure, and the leaked gas recovery cavity is communicated with an external leaked gas recovery device through a pipeline.
10. The tandem dry gas seal device for an industrial steam turbine according to claim 1 or 9, wherein: the pneumatic pressure groove is a one-way groove or a two-way groove; the depth of the one-way groove is 3-20 μm, and the width of the dam area of the pneumatic groove pressing is 0.25-0.75 times of the width of the sealing surface; the movable ring is made of silicon carbide, silicon nitride or hard alloy; the static ring is made of graphite or silicon carbide with a diamond-like film plated on the surface.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010810301.6A CN111828100A (en) | 2020-08-13 | 2020-08-13 | Serial dry gas sealing device for industrial steam turbine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010810301.6A CN111828100A (en) | 2020-08-13 | 2020-08-13 | Serial dry gas sealing device for industrial steam turbine |
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| CN111828100A true CN111828100A (en) | 2020-10-27 |
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| CN202010810301.6A Pending CN111828100A (en) | 2020-08-13 | 2020-08-13 | Serial dry gas sealing device for industrial steam turbine |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112880989A (en) * | 2021-01-08 | 2021-06-01 | 西华大学 | Testing device for characteristic parameters of fluid pressure membrane |
| CN114215853A (en) * | 2021-12-02 | 2022-03-22 | 北京航天石化技术装备工程有限公司 | Combined sealing device for rotating shaft of pyrolysis reactor |
| CN114278733A (en) * | 2021-12-23 | 2022-04-05 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Rotary sealing device controlled by wave spring |
| CN114961891A (en) * | 2022-06-16 | 2022-08-30 | 江西中发天信航空发动机科技有限公司 | Method and device for measuring leakage amount of aero-engine labyrinth seal structure |
| CN116733975A (en) * | 2023-08-14 | 2023-09-12 | 东营海森密封技术有限责任公司 | Dynamic and static pressure combined type air film sealing device |
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2020
- 2020-08-13 CN CN202010810301.6A patent/CN111828100A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112880989A (en) * | 2021-01-08 | 2021-06-01 | 西华大学 | Testing device for characteristic parameters of fluid pressure membrane |
| CN112880989B (en) * | 2021-01-08 | 2023-08-08 | 西华大学 | Testing device for characteristic parameters of fluid pressure membrane |
| CN114215853A (en) * | 2021-12-02 | 2022-03-22 | 北京航天石化技术装备工程有限公司 | Combined sealing device for rotating shaft of pyrolysis reactor |
| CN114215853B (en) * | 2021-12-02 | 2024-02-09 | 北京航天石化技术装备工程有限公司 | Combined sealing device for pyrolysis reactor rotating shaft |
| CN114278733A (en) * | 2021-12-23 | 2022-04-05 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Rotary sealing device controlled by wave spring |
| CN114278733B (en) * | 2021-12-23 | 2023-11-07 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Wave spring controlled rotary sealing device |
| CN114961891A (en) * | 2022-06-16 | 2022-08-30 | 江西中发天信航空发动机科技有限公司 | Method and device for measuring leakage amount of aero-engine labyrinth seal structure |
| CN114961891B (en) * | 2022-06-16 | 2023-05-09 | 江西中发天信航空发动机科技有限公司 | Method and device for measuring leakage quantity of aero-engine comb tooth sealing structure |
| CN116733975A (en) * | 2023-08-14 | 2023-09-12 | 东营海森密封技术有限责任公司 | Dynamic and static pressure combined type air film sealing device |
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