CN115234317A - Three-layer shell steam turbine steam inlet structure and steam turbine - Google Patents

Three-layer shell steam turbine steam inlet structure and steam turbine Download PDF

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Publication number
CN115234317A
CN115234317A CN202210861274.4A CN202210861274A CN115234317A CN 115234317 A CN115234317 A CN 115234317A CN 202210861274 A CN202210861274 A CN 202210861274A CN 115234317 A CN115234317 A CN 115234317A
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China
Prior art keywords
ring
sealing
threaded
shell
valve
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CN202210861274.4A
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Chinese (zh)
Inventor
康明
郝震震
孙维杰
于晶晶
王福光
王海涛
朱斌
叶兴柱
黄庆华
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Shanghai Electric Power Generation Equipment Co Ltd
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Shanghai Electric Power Generation Equipment Co Ltd
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Application filed by Shanghai Electric Power Generation Equipment Co Ltd filed Critical Shanghai Electric Power Generation Equipment Co Ltd
Priority to CN202210861274.4A priority Critical patent/CN115234317A/en
Publication of CN115234317A publication Critical patent/CN115234317A/en
Pending legal-status Critical Current

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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
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
    • 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
    • F01D11/003—Preventing or minimising internal leakage of working-fluid, e.g. between stages by packing rings; Mechanical seals
    • 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
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/10—Final actuators

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gasket Seals (AREA)

Abstract

The application provides a three shells steam turbine admission structure and steam turbine, the admission structure includes admission valve, three shells and intubate. The admission valve includes valve housing and valve diffuser. The three-layer shell comprises an outer shell, an outer inner shell and an inner shell. The housing is connected with the valve housing flange in a sealing way. The insertion tube includes an inner ring portion, an outer ring portion, and a through-hole. The first end of the outer ring part is tightly connected with the valve shell through a sealing ring, and the second end is tightly connected with the flange of the outer inner shell. The first end of the inner ring part is closely connected with the valve diffuser through a sealing ring, and the second end is closely connected with the inner shell through the sealing ring. The intubation tube, the valve shell and the valve diffuser enclose a first interlayer cavity, and the intubation tube, the outer inner shell and the inner shell enclose a second interlayer cavity. The through hole communicates the first and second interlayer cavities. The first interlayer cavity, the second interlayer cavity and the through hole form a first sealing cavity. The valve shell, the outer shell, the insertion pipe and the outer inner shell enclose a second sealing cavity. This application can improve valve diffuser, inner shell and outer inner shell working condition of being in service, improves the pressure and bears the upper limit, reduces the risk that produces the inefficacy.

Description

Three-layer shell steam turbine steam inlet structure and steam turbine
Technical Field
The application relates to the technical field of power station steam turbines, in particular to a three-layer shell steam turbine steam inlet structure and a steam turbine.
Background
The steam turbine refers to a turbine using steam as a medium, and the main purpose of the turbine is to convert heat energy into mechanical energy. The working medium of the steam turbine is high-temperature high-pressure steam, so that the steam turbine is always in a high-temperature high-pressure working condition when working, and the high-temperature high-pressure environment can bring a large failure risk to the structure. Therefore, in order to reduce such a risk, steam turbines of the prior art generally employ double shell turbines and triple shell turbines.
In a double shell steam turbine, the inner shell is arranged around the rotor and the outer shell is arranged around the inner shell, which results in a movement of the inner shell relative to the valve due to temperature variations. The valve includes a valve housing and a valve diffuser disposed within the valve, and high stresses during operation may cause the valve diffuser to deform to affect turbine operating performance, and therefore an angular sealing ring is disposed between the valve diffuser and the inner casing to balance thermal displacement between the valve diffuser and the inner casing.
However, as the operating parameters of the steam turbine, such as pressure, temperature, and the like, are higher and are limited by strength and materials, the double-shell steam turbine cannot meet the working requirements, and the temperature gradient in the thickness direction of the cylinder and the consumption of expensive high-temperature materials must be reduced by adopting a three-shell structure.
A typical three-shell steam turbine includes an inner shell, an outer shell, and an outer inner shell between the inner and outer shells, the outer inner shell also being thermally displaced due to thermal changes, which may interfere with a valve diffuser, and in addition, the space between the inner and outer shells, the space between the outer and inner shells should be sealed and should avoid excessive mechanical stress due to thermal displacement.
In the prior art, patent document CN104033190A discloses a steam inlet structure of a three-layer casing steam turbine, in which a seal cavity formed between an outer casing and an inner casing extends between a valve casing and a valve diffuser, so as to reduce a pressure difference and a temperature difference experienced by the valve diffuser, and thus reduce high stress caused by a high pressure difference and a high temperature difference. However, in CN104033190A, the inner casing is connected to the valve diffuser through only one angular sealing ring, and the steam pressure and temperature range which can be endured are limited. When the pressure difference and the temperature difference between the inner wall and the outer wall of the valve diffuser and between the inner wall and the outer wall of the inner shell are too large, the sealing line established at the connection part of the inner shell and the valve diffuser has the risk of failure.
Disclosure of Invention
An object of the embodiment of this application is to provide a three shells steam turbine admission structure, its operational environment that can effectively improve valve diffuser, inner shell and outer inner shell reduces the risk that produces structural failure and sealing line and become invalid, improves the pressure and the temperature of valve diffuser, inner shell, outer inner shell simultaneously and bears the upper limit.
It is a second object of an embodiment of the present application to provide a steam turbine using the above steam intake structure.
In a first aspect, a three-layer casing steam turbine steam inlet structure is provided, which comprises a steam inlet valve, a three-layer casing and a cannula.
Wherein, the admission valve includes valve casing and lies in the valve diffuser of valve casing inboard. The three-layer shell comprises an outer shell, an outer inner shell and an inner shell which are sequentially arranged, and the outer shell is hermetically connected with the outer side of the valve shell through a flange structure. The cannula includes an inner collar portion, an outer collar portion, and a through-hole. The outer ring part comprises a first end and a second end, the first end of the outer ring part is connected with the valve shell in a sealing mode through a first sealing ring, and the second end of the outer ring part is connected with the inner outer shell in a sealing mode through a flange structure. The inner ring part comprises a first end and a second end, the first end of the inner ring part is in sealing connection with the valve diffuser through a second sealing ring, and the second end of the inner ring part is in sealing connection with the inner shell through a third sealing ring. The intubation tube, the valve shell and the valve diffuser enclose a first interlayer cavity together, and the intubation tube, the outer inner shell and the inner shell enclose a second interlayer cavity together. The through hole is communicated with the first interlayer cavity and the second interlayer cavity. The first interlayer cavity, the through hole and the second interlayer cavity form a first sealing cavity. The valve shell, the outer shell, the insertion pipe and the outer inner shell enclose a second sealing cavity together.
In one embodiment, the pressure of the steam passing through the passage formed by the valve diffuser, the insertion tube and the inner side of the inner casing is P 0 The first sealed cavity and the second sealed cavity are filled with steam, and the steam pressure in the first sealed cavity is P 1 The steam pressure in the second sealed cavity is P 2 ，P 0 、P 1 And P 2 Satisfy P 0 ＞P 1 ＞P 2 。
In an embodiment, the plurality of through-holes is distributed uniformly or non-uniformly along the circumference between the inner ring portion and the outer ring portion of the cannula.
In one embodiment, the first seal ring, the second seal ring and the third seal ring each include a movable end and a fixed end; the end face of the first end of the outer ring part of the insertion pipe is provided with a first annular groove, the end face of the first end of the inner ring part of the insertion pipe is provided with a second annular groove, and the end face of the inner shell, which is used for being connected with the insertion pipe, is provided with a third annular groove; the fixed end of the first sealing ring is hermetically connected with the valve shell, the movable end of the first sealing ring is inserted into the first annular groove, and the movable end of the first sealing ring is in sliding seal with the first annular groove; the fixed end of the second sealing ring is hermetically connected with the valve diffuser, the movable end of the second sealing ring is inserted into the second annular groove, and the movable end of the second sealing ring is in sliding seal with the second annular groove; the fixed end of the third sealing ring is connected with the second end of the inner ring part of the insertion pipe in a sealing mode, the movable end of the third sealing ring is inserted into the third ring groove, and the movable end of the third sealing ring is in sliding sealing with the third ring groove.
In an implementation scheme, the first end of the outer ring part of the insertion pipe is in threaded fastening and sealing fit with the first threaded ring; the first threaded ring is provided with a first annular groove matched with the movable end of the first sealing ring.
In an implementation scheme, the insertion tube further comprises a second threaded ring, and the first end of the inner ring part of the insertion tube is in threaded fastening and sealing fit with the second threaded ring; the second thread ring is provided with a second ring groove matched with the movable end of the second sealing ring.
In an implementation scheme, the device further comprises a third threaded ring, one end of the inner shell, which is used for being connected with the cannula, is in threaded fastening and sealing fit with the third threaded ring; the third threaded ring is provided with a third annular groove matched with the movable end of the third sealing ring.
In an implementable version, further comprising at least two of the first threaded ring, the second threaded ring, and the third threaded ring; the first end of the inner ring part of the insertion pipe is in threaded fastening and sealing fit with the second threaded ring; the second threaded ring is provided with a second annular groove matched with the movable end of the second sealing ring; the first end of the inner ring part of the insertion pipe is in threaded fastening and sealing fit with the second threaded ring; the second threaded ring is provided with a second annular groove matched with the movable end of the second sealing ring; one end of the inner shell, which is used for being connected with the cannula, is in threaded fastening and sealing fit with the third threaded ring; the third threaded ring is provided with a third ring groove matched with the movable end of the third sealing ring.
In an implementable aspect, the device further comprises a first threaded bushing, a second threaded bushing and a third threaded bushing; the first threaded bushing is in threaded fastening and sealing fit with the downstream end part of the valve housing in the steam circulation direction, and an annular groove for fixing the first sealing ring is formed by the body of the first threaded bushing and the end surface of the downstream end part of the valve housing in the steam circulation direction; the second threaded bushing is in threaded fastening and sealing fit with the downstream end part of the valve diffuser in the steam circulation direction, and an annular groove for fixing a second sealing ring is formed between the body of the second threaded bushing and the end surface of the downstream end part of the valve diffuser in the steam circulation direction; the third threaded bushing is in threaded fastening and sealing fit with the second end of the inner ring portion of the insertion pipe, and an annular groove for fixing the third sealing ring is formed by the body of the third threaded bushing and the end face of the second end of the inner ring portion.
According to the second aspect of the application, the steam turbine is further provided, and the steam turbine comprises the three-layer-shell steam turbine steam inlet structure.
Compared with the prior art, the beneficial effect of this application is:
among the technical scheme of this application, through second seal chamber and first seal chamber, realize accepting the function of pressure differential and difference in temperature step by step, avoid basically appearing the abominable operating mode of high-pressure differential and high-temperature difference, reduce mechanical stress and thermal stress to effectively improve the operational environment of valve diffuser, inner shell and outer inner shell, reduce the risk that produces the structural failure.
Meanwhile, structural coupling is formed between the inner shell and the valve diffuser through the inner ring part of the insertion pipe, and the original sealing ring is changed into two sealing rings, so that the thermal displacement of the inner shell and the valve diffuser can be better accepted through two connections, and the failure risk of a sealing line at the sealing ring is effectively reduced.
Compare all to be independent existence's structure between original sealing ring, this application links up three sealing ring with the help of an intubate to the thermal displacement of each part is accepted better to the mode of synergism, can reduce the volume of the thermal displacement that every sealing ring bore relatively, reduces the pressure of single sealing ring, reduces the inefficacy risk of the sealing line of sealing ring from this.
The first interlayer cavity and the second interlayer cavity of the first sealing cavity are communicated through the through holes to form pressure self-regulation inside the first sealing cavity, so that the thermal displacement of the inner shell and the valve diffuser is self-regulated and self-buffered inside the first sealing cavity and then transmitted to the valve shell and the outer shell, and the regulation of the whole pressure difference and the temperature difference is smoother. And the first sealing cavity is in a self-adjusting and self-buffering structural form, so that the first sealing cavity can bear higher steam pressure and temperature, the upper pressure and temperature bearing limits of the valve diffuser, the inner shell and the outer inner shell are improved, and the applicable steam parameter range is further expanded.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
FIG. 1 is a schematic illustration of an inlet structure for a three-shell steam turbine according to an exemplary embodiment of the present application;
FIG. 2 is a schematic illustration of a three-shelled steam turbine steam inlet configuration using three threaded rings in accordance with an embodiment of the present application;
FIG. 3 is a schematic illustration of a three-shelled steam turbine steam inlet configuration using a threaded ring according to an embodiment of the present application;
FIG. 4 is a schematic illustration of a three casing steam turbine inlet configuration utilizing two threaded rings in accordance with an exemplary embodiment of the present application;
FIG. 5 is a schematic illustration of a steam admission configuration for a three-shelled steam turbine according to an exemplary embodiment of the present application;
fig. 6 is a schematic structural diagram illustrating a seal ring of a steam inlet structure of a three-shell steam turbine according to an embodiment of the present application.
In the figure: 11. a valve housing; 12. a valve diffuser; 21. a housing; 22. an outer and inner shell; 23. an inner shell; 231. a third ring groove; 30. inserting a tube; 31. an inner race portion; 311. a second ring groove; 32. an outer ring portion; 321. a first ring groove; 33. a through hole; 41. a first seal ring; 42. a second seal ring; 43. a third seal ring; 401. a movable end; 402. a fixed end; 51. a first sealed chamber; 511. a first interlayer cavity; 512. a second interlayer cavity; 52. a second sealed chamber; 61. a first threaded ring; 62. a second threaded ring; 63. a third threaded ring; 71. a first threaded bushing; 72. a second threaded bushing; 73. a third threaded bushing; 100. a steam inlet central line; 200. the steam inlet direction.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that fig. 1 to 4 are only upper half schematic views of sectional views of the steam inlet structure, the steam inlet central line 100 is a central axis of the steam inlet valve, and the steam inlet direction 200 indicates a flow direction of the high-temperature high-pressure steam.
In accordance with a first aspect of the present application, as shown in FIGS. 1, 5 and 6, there is first provided a three-shell steam turbine steam admission structure including a steam admission valve, a three-shell, and a spigot 30.
The intake valve includes a valve housing 11 and a valve diffuser 12 located inside the valve housing 11. The three-layer shell comprises an outer shell 21, an outer inner shell 22 and an inner shell 23 which are sequentially arranged, and the outer shell 21 is hermetically connected with the outer side of the valve shell 11 through a flange structure.
Cannula 30 includes an inner collar portion 31, an outer collar portion 32, and a throughbore 33. The outer ring portion 32 includes a first end and a second end, the first end of the outer ring portion 32 is sealingly connected to the valve housing 11 by a first sealing ring 41, and the second end of the outer ring portion 32 is sealingly connected to the inner housing 22 by a flange structure. The inner ring portion 31 includes a first end and a second end, the first end of the inner ring portion 31 is sealingly connected to the valve diffuser 12 by a second sealing ring 42, and the second end of the inner ring portion 31 is sealingly connected to the inner casing 23 by a third sealing ring 43. The insertion tube 30, the valve housing 11 and the valve diffuser 12 together enclose a first interlayer cavity 511, and the insertion tube 30, the outer inner shell 22 and the inner shell 23 together enclose a second interlayer cavity 512. The through hole 33 communicates the first interlayer chamber 511 and the second interlayer chamber 512. The first interlayer chamber 511, the penetrating hole 33, and the second interlayer chamber 512 constitute a first seal chamber 51. The valve housing 11, the outer shell 21, the insert tube 30 and the inner shell 22 together enclose a second sealed cavity 52.
The first seal ring 41, the second seal ring 42, and the third seal ring 43 are all angular seal rings.
In the steam inlet structure of the steam turbine of the above embodiment, during operation, high-temperature and high-pressure steam passes through a passage formed by the valve diffuser 12, the insertion pipe 30 and the inner casing 23, so that a large pressure difference and a large temperature difference are brought to the inner wall and the outer wall of the valve diffuser 12 and the inner wall and the outer wall of the inner casing 23, in order to relieve the pressure difference and the temperature difference, the first sealing cavity 51 and the second sealing cavity 52 are sequentially arranged outside the valve diffuser 12, the pressure and the temperature in the first sealing cavity 51 are equivalent to or smaller than the internal steam pressure and temperature, the pressure difference and the temperature difference between the inner wall and the outer wall of the valve diffuser 12 are reduced, the pressure difference and the temperature difference between the inner wall and the outer wall of the inner casing 23 are also reduced, and further, high stress caused by the high temperature difference and the high pressure difference is reduced, thereby improving the service condition of the valve 12 and the inner casing 23, and reducing the risk of structural failure.
Meanwhile, the pressure and the temperature in the second sealed cavity 52 are equivalent to or lower than the steam pressure and the temperature in the first sealed cavity 51, so that the temperature difference and the pressure difference born by the outer inner shell 22 are reduced, the generated high stress is reduced, the service condition of the outer inner shell 22 is improved, and the failure risk is reduced.
It can be known from the above that, through second seal chamber 52 and first seal chamber 51, realize accepting the function of pressure differential and difference in temperature step by step, avoid appearing the abominable operating mode of high pressure differential and high temperature difference basically, reduce mechanical stress and thermal stress to effectively improve the operational environment of valve diffuser 12, inner shell 23 and outer inner shell 22, reduce the risk that produces the structural failure.
Meanwhile, structural coupling is formed between the inner shell 23 and the valve diffuser 12 through the inner ring part 31 of the insertion pipe 30, and an original sealing ring is changed into two sealing rings, so that thermal displacement generated by thermal deformation of the inner shell 23 and the valve diffuser 12 can be better borne, and the failure risk of the whole sealing line at the sealing rings is effectively reduced.
Compare all be independent structures that exist between original sealing ring, this application links up three sealing ring with the help of a intubate 30 to the thermal displacement of each part is accepted better to the mode of synergism, can reduce the volume of the thermal displacement that every sealing ring bore relatively, reduces the pressure of single sealing ring, reduces the inefficacy risk of the whole circle sealing line of sealing ring from this.
Further, the first seal chamber 51 is further optimized as a first interlayer chamber 511 and a second interlayer chamber 512 which communicate through the penetrating hole 33. When the inner shell 23 slightly expands along its circumferential direction, the volume of the second interlayer cavity 512 slightly decreases, and in order to keep the balance of the internal pressure in the first seal cavity 51, a small amount of steam in the second interlayer cavity 512 enters the first interlayer cavity 511 through the through holes 33, but since the total pressure and temperature of the first seal cavity 51 are substantially constant, the pressure of the internal steam on the inner shell 23 is quickly absorbed by the pressure in the second interlayer cavity 512. When the first interlayer cavity 511 at the outer wall of the valve diffuser 12 is affected by the thermal displacement of the valve diffuser 12, the cavity volume of the first interlayer cavity 511 is slightly reduced, and in order to keep the balance of the internal pressure of the first seal cavity 51, a small amount of steam in the first interlayer cavity 511 enters the second interlayer cavity 512 through the through holes 33, but since the total pressure and the temperature of the first seal cavity 51 are basically constant, the pressure of the internal steam on the valve diffuser 12 is quickly absorbed by the pressure in the first interlayer cavity 511. Therefore, the two interlayer cavities, namely the first interlayer cavity 511 and the second interlayer cavity 512 of the first sealed cavity 51 are communicated with each other through the through hole 33 to form pressure self-regulation inside the first sealed cavity 51, so that the thermal displacement of the inner shell 23 and the valve diffuser 12 is self-regulated and self-buffered inside the first sealed cavity 51 and then transmitted to the valve shell 11 and the outer shell 21, the regulation on the whole pressure difference and the temperature difference is smoother, the self-regulation and self-buffering functions of the first sealed cavity 51 can bear higher steam pressure and temperature, and the upper pressure bearing limit of the valve diffuser 12, the inner shell 23 and the like is improved.
It should be noted that the flange structure of the valve housing 11 and the flange structure of the outer housing 21, and the flange structure of the insertion tube 30 and the outer housing 22 are commonly used, and the positions of the flange structures are illustrated by a central line.
It should be noted that the heights of the inner wall of the valve diffuser 12, the inner wall of the insertion tube 30 and the inner wall of the inner casing 23 are consistent, the profile is smooth, and there are substantially no protrusions and corners blocking the steam flow, so as to reduce the generation of turbulence as much as possible.
In one embodiment, as shown in fig. 1, the pressure of the steam passing through the passage formed by the valve diffuser 12, the insertion pipe 30 and the inner side of the inner casing 23 is P 0 The first sealed cavity 51 and the second sealed cavity 52 are filled with steam, and the steam pressure in the first sealed cavity 51 is P 1 The pressure of the steam in the second sealed cavity 52 is P 2 ，P 0 、P 1 And P 2 Satisfy P 0 ＞P 1 ＞P 2 This stepwise decreasing pressure optimizes the mechanical and thermal stress loading of the valve diffuser 12, inner casing 23 and outer inner casing 22, reducing the risk of structural failure or fatigue failure of the valve diffuser 12 due to excessive stress during start-up, shut-down and variable load operation. At the same time, P 0 ＞P 1 ＞P 2 The pressure characteristics of the valve diffuser 12, the inner casing 23 and the outer inner casing 22 are all subjected to pressure difference within a certain controllable range, so that the components have a certain tendency of expanding outwards, the connection part of the sealing ring is tighter, and the established whole circle of sealing line keeps good sealing effect.
In one embodiment, when P is 0 28MPa, 600 ℃, and the steam pressure in the first sealed cavity 51 is P 1 15MPa, 480 ℃, and the steam pressure in the second sealed cavity 52 is P 2 5.5MPaa, at 400 ℃, the structure of this embodiment can still maintain good stability, and it does not generate excessive mechanical and thermal stress, and can reduce the possibility of generating structure and sealing failure. In the solution of the patent document mentioned in the background, the internal steam pressure, i.e. P 0 The operating pressure is lower, the usable range is limited, and the P is increased 0 In the process, the structure has larger increase of each direction expansion and thermal displacement, and the risk of failure of the structure and the whole sealing line is increased.
In one embodiment, the plurality of through-going holes 33 are evenly or uniformly distributed along the circumference between the inner 31 and outer 32 ring portions of the cannula 30, preferably evenly distributed circumferentially to make the vapor communication between the first 511 and second 512 sandwich cavities as gradual as possible.
In one embodiment, as shown in fig. 1 and 6, the first seal ring 41, the second seal ring 42, and the third seal ring 43 each include a movable end 401 and a fixed end 402; the end face of the first end of the outer ring part 32 of the insertion tube 30 is provided with a first annular groove 321, the end face of the first end of the inner ring part 31 of the insertion tube 30 is provided with a second annular groove 311, and the end face of the inner shell 23 used for being connected with the insertion tube 30 is provided with a third annular groove 231; the fixed end 402 of the first sealing ring 41 is connected with the valve housing 11 in a sealing manner, the movable end 401 of the first sealing ring 41 is inserted into the first annular groove 321, and the movable end 401 of the first sealing ring 41 is in sliding seal with the first annular groove 321; the fixed end 402 of the second sealing ring 42 is connected with the valve diffuser 12 in a sealing manner, the movable end 401 of the second sealing ring 42 is inserted into the second annular groove 311, and the movable end 401 of the second sealing ring 42 is in sliding sealing with the second annular groove 311; the fixed end 402 of the third sealing ring 43 is sealingly connected to the second end of the inner ring portion 31 of the insertion tube 30, the movable end 401 of the third sealing ring 43 is inserted into the third ring groove 231, and the movable end 401 of the third sealing ring 43 is slidably sealed with the third ring groove 231.
In the above solution, the sliding seals of the movable ends 401 of the first, second and third sealing rings in the annular grooves are used for receiving the thermal displacement of the components such as the valve diffuser 12, the inner casing 23, the outer inner casing 22, and the like along the steam flowing direction, so as to provide a buffer for the displacement change caused by the thermal displacement and ensure a good sealing effect.
For the position of the ring groove matched with the movable end 401 of the sealing ring, sliding friction is born, the wear resistance of the sealing position is increased, and sliding sealing is ensured, so that the area where the ring groove is located needs to be subjected to special process treatment, such as surfacing welding or spraying, subsequent heat treatment and the like, but the treatment generally needs to carry out relevant process operation on the whole part, and the treatment time is greatly increased. Meanwhile, if the overlay welding has a defect of a large area, the whole part can be scrapped. Therefore, in order to solve this problem, the inventors further propose the following.
In one embodiment, as shown in FIG. 2, further comprising a first threaded ring 61, the first end of the outer collar portion 32 of the cannula 30 is in threaded sealing engagement with the first threaded ring 61; the first threaded ring 61 is provided with a first annular groove 321 which cooperates with the movable end 401 of the first sealing ring 41.
In one embodiment, as shown in fig. 2, further comprising a second threaded ring 62, the first end of the inner ring portion 31 of the cannula 30 is in threaded sealing engagement with the second threaded ring 62; the second threaded ring 62 is provided with a second ring groove 311 which cooperates with the free end 401 of the second sealing ring 42.
In one embodiment, as shown in FIG. 2, further comprising a third threaded ring 63, the end of the inner housing 23 for connection to the cannula 30 is in threaded sealing engagement with the third threaded ring 63; the third threaded ring 63 is provided with a third ring groove 231 which cooperates with the movable end 401 of the third sealing ring 43.
The above-mentioned structural designs of the first threaded ring 61, the second threaded ring 62 and the third threaded ring 63 may be any one of them, for example, as shown in fig. 3; three may be used, such as shown in FIG. 2; any combination of two of these may also be used, such as shown in FIG. 4. Fig. 2, 3 and 4 are only schematic diagrams of the arrangement positions of the threaded rings, and are not limited to the embodiments illustrated in fig. 2 to 4 of the present embodiment.
For parts not using a threaded ring, the ring groove for engaging with the free end 401 of the sealing ring may be cut directly on the corresponding part.
For the processes of surfacing, spraying, post-heat treatment and the like of the ring groove, the processes can be performed only on the first threaded ring 61, the second threaded ring 62 and the third threaded ring 63, the original damage risk to the component is transferred to the threaded rings, the structural volume of the threaded rings is far smaller than that of the structures such as the inner shell 23, and the related surfacing, spraying and the like are more convenient to perform. In addition, the first, second and third threaded rings 61, 62, 63 are relatively inexpensive to replace if damaged.
In one embodiment, due to the high steam pressure and temperature inside the valve diffuser 12, the insert tube 30, and the inner casing 23, the operation is worse, the magnitude of the thermal displacement is large, the sliding friction between the movable end 401 of the sealing ring and the ring groove is relatively frequent, and the possibility of the sealing failure at the ring groove position is increased. In order to facilitate later maintenance, the solution in fig. 4 is preferably adopted, i.e. the second threaded ring 62 and the third threaded ring 63 are used, so that when the second annular groove 311 and the third annular groove 231 are damaged, the second threaded ring 62 and the third threaded ring 63 can be directly replaced.
If the insert tube 30 is convenient due to the build-up welding, spraying and heat treatment, as shown in fig. 3, the third threaded ring 63 may be used only at the mating portion of the inner shell 23 and the third seal ring 43, in order to further reduce the assembly complexity of the structure.
In one embodiment, if assembly complexity is not a concern, a first threaded ring 61, a second threaded ring 62, and a third threaded ring 63 may be used simultaneously, as shown in FIG. 2.
As shown in fig. 1 to 4, a first threaded bushing 71, a second threaded bushing 72, and a third threaded bushing 73 are further included. The first threaded bush 71 is threadedly and sealingly engaged with the downstream end portion in the steam flow direction of the valve housing 11, and the body of the first threaded bush 71 and the end face of the downstream end portion in the steam flow direction of the valve housing 11 form an annular groove for fixing the first seal ring 41. The second threaded bushing 72 is in threaded sealing engagement with the downstream end portion of the valve diffuser 12 in the steam flow direction, and an annular groove for fixing the second seal ring 42 is formed by the body of the second threaded bushing 72 and the end surface of the downstream end portion of the valve diffuser 12 in the steam flow direction. The third threaded bushing 73 is in threaded fastening and sealing engagement with the second end of the inner ring portion 31 of the insert tube 30, and the body of the third threaded bushing 73 and the end face of the second end of the inner ring portion 31 form an annular groove for fixing the third sealing ring 43. The annular grooves formed by the first, second and third threaded bushings 71, 72, 73 and the corresponding end faces facilitate fixing the fixed end of the sealing ring on the one hand and balance the relative thermal displacement between the outer inner casing 22, the valve diffuser 12, the inner casing 23 and the valve housing 11 perpendicular to the flow direction of the steam on the other hand.
The first to third sealing rings are adapted to the respective expansion and thermal displacement of the valve housing 11, the insertion tube 30, the valve diffuser 12, the outer inner shell 22 and the inner shell 23 under the combined action of the pressure difference and the thermal stress of the sealing chambers and by means of the deformability and repositionability of the structures thereof, so that the sealing surfaces of the entire ring can be maintained all the time during operation.
In one embodiment, sealing rings may be provided at the flange structure connection of the outer housing 21 and the valve housing 11 and at the flange structure connection of the inner housing 22 and the insertion tube 30 to ensure the sealing performance of the joint surface.
Furthermore, sealing rings may be provided at the connection of the first threaded bushing 71 and the valve housing 11, the connection of the second threaded bushing 72 and the valve diffuser 12, and the connection of the third threaded bushing 73 and the insert pipe 30, respectively, to ensure the sealing performance of the joint surface.
Further, sealing rings may be provided at the connection of the first threaded ring 61 and the insertion tube 30, the connection of the second threaded ring 62 and the insertion tube 30, and the connection of the third threaded ring 63 and the inner shell 23, to ensure the sealing performance of the joint surfaces.
According to the second aspect of the application, the steam turbine is further provided, and the steam turbine comprises the three-layer-shell steam turbine steam inlet structure.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. A three-layer shell steam turbine steam inlet structure is characterized by comprising:
an inlet valve comprising a valve housing (11) and a valve diffuser (12) located inside the valve housing (11);
the three-layer shell comprises an outer shell (21), an outer inner shell (22) and an inner shell (23) which are sequentially arranged, wherein the outer shell (21) is hermetically connected with the outer side of the valve shell (11) through a flange structure;
a cannula (30) comprising an inner collar portion (31), an outer collar portion (32) and a through-going bore (33);
the outer ring part (32) comprises a first end and a second end, the first end of the outer ring part (32) is connected with the valve shell (11) in a sealing mode through a first sealing ring (41), and the second end of the outer ring part (32) is connected with the outer inner shell (22) in a sealing mode through a flange structure;
the inner ring part (31) comprises a first end and a second end, the first end of the inner ring part (31) is connected with the valve diffuser (12) in a sealing mode through a second sealing ring (42), and the second end of the inner ring part (31) is connected with the inner shell (23) in a sealing mode through a third sealing ring (43);
the insertion pipe (30), the valve housing (11) and the valve diffuser (12) jointly enclose a first interlayer cavity (511), and the insertion pipe (30), the outer inner shell (22) and the inner shell (23) jointly enclose a second interlayer cavity (512);
the through hole (33) is communicated with the first interlayer cavity (511) and the second interlayer cavity (512);
the first interlayer cavity (511), the through hole (33) and the second interlayer cavity (512) form a first sealing cavity (51);
the valve housing (11), the outer shell (21), the cannula (30) and the inner outer shell (22) jointly enclose a second sealing cavity (52).
2. The steam admission structure of a three-casing steam turbine according to claim 1, wherein the steam pressure passing through the passage formed by the valve diffuser (12), the insertion pipe (30) and the inner side of the inner casing (23) is P 0 Steam is introduced into the first sealed cavity (51) and the second sealed cavity (52), and the steam pressure in the first sealed cavity (51) is P 1 The pressure of steam in the second sealed cavity (52) is P 2 ，P 0 、P 1 And P 2 Satisfies P 0 ＞P 1 ＞P 2 。
3. The steam turbine inlet structure of a triple-shelled steam turbine according to claim 1, characterized in that a plurality of the through-holes (33) are uniformly or non-uniformly distributed along the circumference between the inner ring portion (31) and the outer ring portion (32) of the insert tube (30).
4. The triple-shell steam turbine inlet construction according to claim 1, characterized in that the first seal ring (41), the second seal ring (42) and the third seal ring (43) each comprise a movable end (401) and a fixed end (402);
a first annular groove (321) is formed in the end face of the first end of the outer ring part (32) of the insertion pipe (30), a second annular groove (311) is formed in the end face of the first end of the inner ring part (31) of the insertion pipe (30), and a third annular groove (231) is formed in the end face, used for being connected with the insertion pipe (30), of the inner shell (23);
the fixed end (402) of the first sealing ring (41) is connected with the valve housing (11) in a sealing manner, the movable end (401) of the first sealing ring (41) is inserted into the first annular groove (321), and the movable end (401) of the first sealing ring (41) is in sliding sealing with the first annular groove (321);
the fixed end (402) of the second sealing ring (42) is connected with the valve diffuser (12) in a sealing mode, the movable end (401) of the second sealing ring (42) is inserted into the second annular groove (311), and the movable end (401) of the second sealing ring (42) is in sliding sealing with the second annular groove (311);
third sealing ring (43) stiff end (402) with intubate (30) the second end sealing connection of inner circle part (31), third sealing ring (43) expansion end (401) inserts third ring groove (231), third sealing ring (43) expansion end (401) with third ring groove (231) sliding seal.
5. The steam inlet structure of a three-shell steam turbine according to claim 4, further comprising a first threaded ring (61), the first end of the outer race portion (32) of the insert tube (30) being in threaded fastening sealing engagement with the first threaded ring (61);
the first threaded ring (61) is provided with the first annular groove (321) cooperating with the mobile end (401) of the first sealing ring (41).
6. The triple-shell steam turbine inlet construction according to claim 4 further comprising a second threaded ring (62), the first end of the inner race portion (31) of the insert tube (30) being in threaded fastening sealing engagement with the second threaded ring (62);
the second threaded ring (62) is provided with the second annular groove (311) cooperating with the movable end (401) of the second sealing ring (42).
7. The steam inlet structure of the three-shell steam turbine according to claim 4, further comprising a third threaded ring (63), wherein one end of the inner shell (23) for connecting with the insert pipe (30) is in threaded fastening and sealing fit with the third threaded ring (63);
the third threaded ring (63) is provided with the third annular groove (231) cooperating with the free end (401) of the third sealing ring (43).
8. The steam inlet structure of a three-shell steam turbine according to claim 4, further comprising at least two of a first threaded ring (61), a second threaded ring (62), and a third threaded ring (63);
a first end of the outer collar portion (32) of the cannula (30) is in threaded fastening sealing engagement with the first threaded ring (61); the first threaded ring (61) is provided with the first annular groove (321) cooperating with the mobile end (401) of the first sealing ring (41);
a first end of the inner ring portion (31) of the cannula (30) is in threaded fastening sealing engagement with the second threaded ring (62); the second threaded ring (62) is provided with the second annular groove (311) cooperating with the active end (401) of the second sealing ring (42);
one end of the inner shell (23) used for being connected with the cannula (30) is in threaded fastening and sealing fit with the third threaded ring (63); the third threaded ring (63) is provided with the third annular groove (231) cooperating with the free end (401) of the third sealing ring (43).
9. The steam inlet structure of a three-shell steam turbine according to any one of claims 4 to 8, further comprising a first threaded bushing (71), a second threaded bushing (72), and a third threaded bushing (73);
the first threaded bushing (71) is in threaded fastening and sealing fit with the downstream end part of the valve housing (11) in the steam flowing direction, and an annular groove for fixing the first sealing ring (41) is formed by the body of the first threaded bushing (71) and the end surface of the downstream end part of the valve housing (11) in the steam flowing direction;
the second threaded bushing (72) is in threaded fastening and sealing fit with the downstream end part of the valve diffuser (12) in the steam flowing direction, and an annular groove for fixing the second sealing ring (42) is formed between the body of the second threaded bushing (72) and the end face of the downstream end part of the valve diffuser (12) in the steam flowing direction;
the third threaded bushing (73) is in threaded fastening and sealing fit with the second end of the inner ring part (31) of the insertion pipe (30), and an annular groove for fixing the third sealing ring (43) is formed by the body of the third threaded bushing (73) and the end face of the second end of the inner ring part (31).
10. A steam turbine comprising a three-shelled steam turbine steam admission structure according to any of claims 1 to 9.
CN202210861274.4A 2022-07-20 2022-07-20 Three-layer shell steam turbine steam inlet structure and steam turbine Pending CN115234317A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210861274.4A CN115234317A (en) 2022-07-20 2022-07-20 Three-layer shell steam turbine steam inlet structure and steam turbine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210861274.4A CN115234317A (en) 2022-07-20 2022-07-20 Three-layer shell steam turbine steam inlet structure and steam turbine

Publications (1)

Publication Number Publication Date
CN115234317A true CN115234317A (en) 2022-10-25

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210861274.4A Pending CN115234317A (en) 2022-07-20 2022-07-20 Three-layer shell steam turbine steam inlet structure and steam turbine

Country Status (1)

Country Link
CN (1) CN115234317A (en)

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