US20100278645A1 - Seal Structure and Control Method Therefor - Google Patents

Seal Structure and Control Method Therefor Download PDF

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Publication number
US20100278645A1
US20100278645A1 US12/769,249 US76924910A US2010278645A1 US 20100278645 A1 US20100278645 A1 US 20100278645A1 US 76924910 A US76924910 A US 76924910A US 2010278645 A1 US2010278645 A1 US 2010278645A1
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US
United States
Prior art keywords
rotor
seal
steam
rotating portion
seal fin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/769,249
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English (en)
Inventor
Kenjiro Narita
Haruyuki Yamazaki
Hiroyuki Doi
Kei Kobayashi
Hajime Toriya
Takeshi Kudo
Yoshitaka Kojima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Power Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Assigned to HITACHI, LTD. reassignment HITACHI, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TORIYA, HAJIME, DOI, HIROYUKI, KOBAYASHI, KEI, KOJIMA, YOSHITAKA, KUDO, TAKESHI, NARITA, KENJIRO, YAMAZAKI, HARUYUKI
Publication of US20100278645A1 publication Critical patent/US20100278645A1/en
Assigned to MITSUBISHI HITACHI POWER SYSTEMS, LTD. reassignment MITSUBISHI HITACHI POWER SYSTEMS, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HITACHI, LTD.
Abandoned legal-status Critical Current

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Classifications

    • 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
    • F01D1/00—Non-positive-displacement machines or engines, e.g. steam turbines
    • F01D1/02—Non-positive-displacement machines or engines, e.g. steam turbines with stationary working-fluid guiding means and bladed or like rotor, e.g. multi-bladed impulse steam turbines
    • 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
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • 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
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/55—Seals

Definitions

  • the present invention relates to a seal structure provided for a steam turbine and a control method therefor.
  • the steam turbine For power-generating plants in which a turbine (steam turbine) is rotated for electric generation by steam generated by a steam generator such as a boiler or the like, the steam turbine includes a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine installed in that order from the upstream side of steam flow.
  • the steam having rotated the low-pressure turbine is introduced via an exhaust hood into a condenser, in which the steam is condensed as feed-water, which is returned to the steam generator.
  • stator blade secured to the inside of a casing is disposed between rotor blades rotated integrally with a rotor. In this way, the stator blade and the rotor blade constitute a stage.
  • the steam introduced into the inside of the casing flows inside the casing of the steam turbine and expands to rotate the rotor while alternately passing through between the stator blades and the corresponding rotor blades secured to the rotor rotatably supported by the casing.
  • the steam passing a rotor blade installed on the most downstream portion of the rotor, i.e., a final-stage rotor blade is discharged to the outside of the casing.
  • a labyrinth seal device having fins is disposed between the rotating portion such as a rotor and the fixed portion such as a stator blade.
  • a member (abradable metal) superior in the easiness of the abrasion is used at a position facing the fin.
  • the fin and the abradable metal are disposed to reduce the clearance between the rotating portion and the fixed portion as much as possible.
  • the fin and the abradable metal often come into contact with each other to increase resistance (rotational resistance) against the rotation of the rotating portion. Therefore, when steam has relatively low pressure, for example, such as during the initial period of starting up the steam turbine, the rotor becomes hard to be rotated. This poses a problem in that it becomes difficult to smoothly start up the steam turbine.
  • the fins provided on the rotating portion and the abradable metal provided on the fixed portion come into contact with each other to generate frictional heat.
  • This frictional heat is transmitted to the rotating portion, which has high-temperature.
  • this heat transmission causes thermal deformation of the rotating portion such as thermal expansion or thermal bending, which affects the rotation of the rotating portion. This poses a problem of lowering the turbine efficiency of the steam turbine.
  • JP-2007-16704-A has a thermal insulation layer between fins provided on the rotating portion and the rotating portion, for example. This prevents frictional heat generated by the contact between the rotating portion and the fixed portion from being transmitted to the rotating portion.
  • the clearance between the fins and the abradable metal is increased in order to prevent the contact between the fins and the abradable metal, the clearance between the rotating portion and the fixed portion is increased to increase the leakage of steam. Thus, it is not probable that the turbine efficiency of the steam turbine can be improved.
  • a seal structure and a control method therefor in which a fin provided on a rotating portion and a spacer provided on a fixed portion are opposed to each other, a fin provided on the fixed portion and a spacer provided on the rotating portion are opposed to each other, the spacers are made of breathable metal and the fin and the spacer provided on the fixed portion are shiftable in a direction coming close to or moving away from the rotating portion.
  • the aspect of the present invention can provide the seal structure and the control method therefor that can improve sealing performance between the rotating portion and the fixed portion, smoothly start up a steam turbine, and suppress the temperature rise of the rotating portion even if the rotating portion is continuously rotated for a long period of time.
  • FIG. 1 is a schematic system diagram of a power-generating plant provided with a steam turbine according to an embodiment of the present invention.
  • FIG. 2 is a partially enlarged view of the steam turbine of FIG. 1 .
  • FIG. 3 is an enlarged view of an A1-portion of FIG. 2 .
  • FIG. 4 is an enlarged view of an A2-portion of FIG. 3 .
  • FIG. 5A is a cross-sectional view taken along the line X 1 -X 1 in FIG. 2 .
  • FIG. 5B is an enlarged view of an A3-portion of FIG. 5A .
  • FIG. 6 is a schematic view illustrating one configurational example of a high-low labyrinth seal device, in which a seal base-plate is provided with seal fins.
  • FIG. 7 is a schematic view illustrating one configurational example of a high-low labyrinth seal device, in which a rotor is provided with seal fins.
  • FIG. 8A is a cross-sectional view taken along the line X 2 -X 2 in FIG. 2 .
  • FIG. 8B is an enlarged view of an A4-portion of FIG. 8A .
  • FIG. 9 is a schematic view illustrating a distal end of a rotor blade.
  • FIG. 10 is a schematic view illustrating one configurational example of a labyrinth seal device equipped with compression springs connecting together piston bodies in a circumferential direction.
  • FIG. 11 is a schematic diagram illustrating one configurational example of a labyrinth seal device in which driving steam is allowed to flow into a pressurizing chamber from a high-pressure steam supply source to thereby move a piston head.
  • a power-generating plant 1 is configured to include a boiler 10 , a steam turbine 2 (a high-pressure turbine 12 , a medium-pressure turbine 14 , and a low-pressure turbine 16 ), a generator 18 , and a condenser 20 .
  • a rotor 2 a of the low-pressure turbine 16 is coupled to a drive shaft 22 of the generator 18 . Rotation of the low-pressure turbine 16 drives the generator 18 for electric generation.
  • the boiler 10 is a steam generator, which is provided with a reheater 24 .
  • the boiler 10 is connected to an inlet side of the high-pressure turbine 12 via a pipe 26 .
  • An outlet side of the high-pressure turbine 12 is connected to the reheater 24 of the boiler 10 via a pipe 28 .
  • the reheater 24 is connected to an inlet side of the medium-pressure turbine 14 via a pipe 30 .
  • An outlet side of the medium-pressure turbine 14 is connected to an inlet side of the low-pressure turbine 16 via a pipe 32 .
  • the pipes 26 and 30 are provided with respective adjusting valves B, each of which functions as a control valve to control an amount of steam St flowing into a corresponding one of the high-pressure turbine 12 and the medium-pressure turbine 14 .
  • the adjusting valves B are controlled by a controller 54 to control the amount of steam St flowing into the high-pressure turbine 12 and the medium-pressure turbine 14 .
  • the steam St generated in the boiler 10 flows into the low-pressure turbine 16 via the high-pressure turbine 12 and the medium-pressure turbine 14 to rotate the rotor 2 a provided in the low-pressure turbine 16 .
  • the steam St discharged from the low-pressure turbine 16 by the rotation of the rotor 2 a passes through an exhaust hood 3 and is condensed and turned into water (feed-water) in the condenser 20 . Thereafter, the feed-water is fed to and heated in the feed-water heater 21 and introduced into the boiler 10 or the steam generator via another feed-water heater (not illustrated), a high-pressure feed-water pump (not illustrated) and the like.
  • the steam turbine 2 (e.g. the high-pressure turbine 12 illustrated in FIG. 1 ) includes a plurality of rotor blades 2 b externally-circumferentially secured to the rotor 2 a and axially arranged in a plurality of rows.
  • the steam turbine 2 includes a casing 2 d embracing the rotor 2 a and the rotor blades 2 b , and a plurality of stator blades 2 c secured to the casing 2 d via corresponding nozzle diaphragm outer-rings 80 .
  • the plurality of rotor blades 2 b and the plurality of stator blades 2 c are alternately arranged in the axial direction of the rotor 2 a to form stages.
  • the externally circumferential direction of the rotor 2 a is hereinafter referred to as a circumferential direction. That is to say, the rotor 2 a is rotated in the circumferential direction.
  • the steam St passing a rotor blade 2 b installed on the most downstream portion of the rotor 2 a , i.e., a final-stage rotor blade 2 b is discharged to the outside of the casing 2 d.
  • a clearance may be provided between a nozzle diaphragm inner-ring 70 installed on distal ends of the stator blades 2 c and the rotor 2 a in some cases.
  • This clearance causes leakage of steam St flowing to the stator blades 2 c .
  • the steam St becoming the leakage steam does not contribute to the rotation of the rotor 2 a . Therefore, the increased amount of leakage steam lowers the turbine efficiency of the steam turbine 2 .
  • a configuration is generally employed in which a seal device such as a labyrinth seal device 60 is assembled between the nozzle diaphragm inner-ring 70 and the rotor 2 a to reduce the clearance between the rotor 2 a and the stator blades 2 c .
  • This configuration can improve the sealing performance between the rotor 2 a and the stator blades 2 c to thereby reduce the amount of leakage steam.
  • the nozzle diaphragm inner-ring 70 is provided on the rotor 2 a side with a seal base-plate 61 equipped with a plurality of seal fins 62 .
  • the seal base-plate 61 is provided at given intervals with a plurality of grooves 63 circumferentially formed in line in the axial direction of the rotor 2 a .
  • the seal fins 62 are secured to the respective grooves 63 by caulking.
  • the rotor 2 a is provided at given intervals with a plurality of grooves 2 a 2 circumferentially formed in line in the axial direction of the rotor 2 a . Seal fins 2 a 1 are secured to the respective grooves 2 a 2 by caulking.
  • seal fins 62 on the seal base-plate 61 side and the corresponding seal fins 2 a 1 on the rotor 2 a side are arranged to alternately overlap each other in the axial direction of the rotor 2 a.
  • the labyrinth seal device 60 is configured to include the seal base-plate 61 provided with the plurality of seal fins 62 .
  • the seal fins 62 on the seal base-plate 61 side and the rotor 2 a have been configured so as not to be in contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the seal base-plate 61 have been configured so as not to be in contact with each other.
  • a minute clearance is defined between each of the seal fins 62 and the rotor 2 a and between each of the seal fins 2 a 1 and the seal base-plate 61 , whereby rotational resistance against the rotation of the rotor 2 a is reduced.
  • a breathable spacer 4 (spacer) made of breathable metal is attached between each of the seal fins 62 on the seal base-plate 61 side and the rotor 2 a and between each of the seal fins 2 a 1 on the rotor 2 a side and the seal base-plate 61 .
  • seal base-plate 61 provided with the seal fins 62 and with the breathable spacers 4 is installed shiftably in a direction coming close to or moving away from the rotor 2 a , i.e., in the rotational-radial direction of the rotor 2 a.
  • the breathable spacer 4 on the seal base-plate 61 side is denoted with reference numeral 4 a and the breathable spacer 4 on the rotor 2 a side is denoted with reference numeral 4 b.
  • the breathable spacers 4 b are attached to the rotor 2 a at respective positions opposed to the corresponding seal fins 62 on the seal base-plate 61 side.
  • the breathable spacers 4 a are attached to the seal base-plate 61 at respective positions opposed to the corresponding seal fins 2 a 1 on the rotor 2 a side.
  • This configuration provides a seal structure in which the breathable spacers 4 made of breathable metal are attached to both the rotor 2 a (the rotating portion) and the seal base-plate 61 (the fixed portion).
  • a method of attaching the breathable spacer 4 to the rotor 2 a and the seal base-plate 61 is not restrictive.
  • the breathable spacer 4 may be secured to the rotor 2 a and the seal base-plate 61 by e.g. brazing.
  • the breathable spacers 4 b on the rotor 2 a side are each circumferentially attached to the outer circumference of the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side are configured to be constantly opposed to each other even during the rotation of the rotor 2 a .
  • the seal fins 2 a 1 on the rotor 2 a side are provided in the circumferential direction.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side are configured to be opposed to each other even during the rotation of the rotor 2 a.
  • Breathable metal used to form the breathable spacer 4 is a metal material structured such that space portions (pores) of porous metal are connected together and gas (steam St) can pass through the inside thereof.
  • the breathable metal is material (abradable metal) superior in the easiness of the abrasion. For example, if the rotor 2 a is rotated in the state where the distal ends of the seal fins 62 on the seal base-plate 61 side are in contact with the corresponding breathable spacers 4 b on the rotor 2 a side (in the contact state), the breathable spacers 4 ( 4 b ) are abraded as shown in FIG. 4 but the seal fins 62 are not damaged.
  • the configuration in which the distal ends of the seal fins 62 come into contact with the respective breathable spacers 4 b on the rotor 2 a side can improve the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a.
  • the configuration in which the distal ends of the seal fins 2 a 1 on the rotor 2 a side come into contact with the respective breathable spacers 4 a (see FIG. 3 ) on the seal base-plate 61 side can improve the sealing performance between the stator blades 2 c and the rotor 2 a.
  • the clearance between the seal fins 62 and the rotor 2 a and between the seal fins 2 a 1 and the seal base-plate 61 is eliminated or made small to improve the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a as shown in FIG. 3 .
  • the spacers made of a raw material superior in the easiness of the abrasion, such as e.g. abradable metal are provided on the rotor 2 a at respective positions opposed to the corresponding seal fins 62 , and on the seal base-plate 61 at respective positions opposed to the corresponding seal fins 2 a 1 .
  • a heat-insulating layer made of a heat-insulating member not illustrated is provided between the spacers on the rotor 2 a side and the rotor 2 a .
  • the rotor 2 a may continuously be rotated for a long period of time so that the spacers rotated integrally with the rotor 2 a are in contact with the seal fins 62 for a long period of time.
  • the frictional heat between the seal fins 62 and the spacers is gradually accumulated so that the heat-insulating layer has high-temperature.
  • the heat of the heat-insulating layer is transmitted to the rotor 2 a , which has high-temperature.
  • the rotor 2 a causes thermal deformation such as thermal bending due to nonuniform temperature distributions.
  • the steam St passing through the inside of the breathable spacer 4 uniformly keeps the breathable spacer 4 at a temperature equal to that of the steam St. In other words, the breathable spacer 4 will not have temperature higher than the steam St.
  • a steam-breathable amount of the breathable spacer 4 has only to be such an amount as not to affect sealing performance and to be an amount that uniformly keeps the breathable spacer 4 at a temperature equal to that of the steam St.
  • the steam-breathable amount of breathable metal used to form the breathable spacer 4 is slight and is a characteristic value of the breathable metal depending on the arrangement density and size of pores. Therefore, it is only necessary to form the breathable spacer 4 by using breathable metal that does not affect sealing performance and can ensure a steam-breathable amount in which an effect is expected of uniformly keeping the breathable spacer 4 at a temperature equal to that of the steam St.
  • the temperature of the breathable spacer 4 is uniformly kept equally to that of the steam St.
  • the rotor 2 a may be rotated for a long period of time so that, for example, the seal fins 62 and the breathable spacers 4 b rotated integrally with the rotor 2 a are in contact with each other for a long period of time. Even in such a case, the temperature of the breathable spacers 4 b will not become higher than that of the steam St. Thus, an effect is produced in which the temperature of the rotor 2 a can be prevented from becoming higher than that of steam St.
  • the rotor 2 a is designed to have heat resistance against the temperature of steam St. If the temperature of the rotor 2 a is kept at the temperature of the steam St, since e.g. excessive thermal stress and thermal deformation such as thermal bending do not occur, the operation of the steam turbine 2 (see FIG. 1 ) is not affected.
  • the labyrinth seal device 60 illustrated in FIG. 3 may be configured such that the breathable spacers 4 are provided on only one of the rotor 2 a side and the seal base-plate 61 side.
  • the amount of steam St passing through the breathable spacer 4 as illustrated in FIG. 4 is slighter than that leaking from the clearance between the seal fin 62 and the rotor 2 a . Therefore, the amount of steam St passing through the breathable spacer 4 does not have an influence on the turbine efficiency of the steam turbine 2 (see FIG. 1 ).
  • seal base-plate 61 is installed shiftably in a direction coming close to or moving away from the rotor 2 a.
  • the nozzle diaphragm inner-ring 70 is provided on the distal ends of the stator blades 2 c on the inner circumferential side thereof so as to extend in the circumferential direction.
  • e.g. six seal base-plates 61 equally divided in the circumferential direction are provided on the end of the nozzle diaphragm inner-ring 70 on the inner circumferential side thereof so as to surround the rotor 2 a.
  • the seal fins 62 are secured to one seal base-plate 61 on the rotor 2 a side by caulking or the like so as to extend upright therefrom along the circumferential direction of the rotor 2 a .
  • the breathable spacers 4 b made of breathable metal are attached to the outer circumference of the rotor 2 a at respective positions opposed to the corresponding seal fins 62 .
  • the breathable spacers 4 a made of breathable metal are attached to one seal base-plate 61 at respective positions opposed to the corresponding seal fins 2 a 1 on the rotor 2 a side so as to be shaped along the circumferential direction.
  • all the seal base-plates 61 are installed on the nozzle diaphragm inner-ring 70 shiftably in a direction coming close to or moving away from the rotor 2 a , i.e., in the rotational-radial direction of the rotor 2 a.
  • the nozzle diaphragm inner-ring 70 is formed with a hollow pressurizing chamber 71 .
  • the hollow pressurizing chamber 71 is internally provided with a piston head 64 reciprocating in a direction coming close to or moving away from the rotor 2 a .
  • the piston head 64 is elastically supported by a plurality of return springs 66 (biasing means) circumferentially arranged, e.g., in two lines.
  • the piston head 64 is biased at an appropriated biasing force by the return springs 66 in a direction moving away from the rotor 2 a.
  • the number of the return springs 66 may be determined appropriately.
  • the pressurizing chamber 71 is configured to communicate with the outside of the nozzle diaphragm inner-ring 70 through a steam passage 72 .
  • steam St flowing through the outside of the nozzle diaphragm inner-ring 70 flows into the pressurizing chamber 71 .
  • the piston head 64 is shifted in a direction coming close to the rotor 2 a.
  • the piston head 64 is provided with a piston body 65 .
  • the piston body 65 extends from the pressurizing chamber 71 toward the rotor 2 a and has an end portion terminating at the outside of the nozzle diaphragm inner-ring 70 .
  • the seal base-plate 61 is attached to the end portion.
  • the piston body 65 may be formed integrally with the piston head 64 , for example.
  • a method of attaching the seal base-plate 61 to the piston body 65 is not restrictive.
  • the seal base-plate 61 may be secured to the piston body 65 by means of screws not illustrated.
  • a movable portion is configured to include the piston head 64 , the piston body 65 , and the seal base-plate 61 .
  • the seal base-plate 61 When the piston head 64 is supported by the biasing force of the return springs 66 at a position away from the rotor 2 a , the seal base-plate 61 is in a state shifted to a position away from the rotor 2 a . In this state, the seal fins 62 on the seal base-plate 61 side are not in contact with the corresponding breathable spacers 4 b , opposed thereto, on the rotor 2 a side (the non-contact state). Thus, a clearance is defined between the seal fins 62 and the corresponding breathable spacers 4 b.
  • the seal fins 2 a 1 on the rotor 2 a side are not in contact with the corresponding breathable spacers 4 a , opposed thereto, on the seal base-plate 61 side. In this state, a clearance is defined between the seal fins 2 a 1 and the corresponding breathable spacers 4 a.
  • the labyrinth seal device 60 in the present embodiment is configured to include the pressurizing chamber 71 , the steam passage 72 , the piston head 64 , the piston body 65 , and the return springs 66 in addition to the seal base-plate 61 .
  • the seal structure including the labyrinth seal device 60 and the seal fins 2 a 1 and breathable spacers 4 b on the rotor 2 a side is assembled into the steam turbine 2 (see FIG. 1 ).
  • the seal fins 62 on the seal base-plate 61 side are in contact with the corresponding breathable spacers 4 b on the rotor 2 a side and the seal fins 2 a 1 on the rotor 2 a side are in contact with the corresponding breathable spacers 4 a on the seal base-plate 61 side.
  • rotational resistance against the rotation of the rotor 2 a is increased; however, if the pressure of the steam St is high, the rotor 2 a can be rotated against the rotational resistance increased by the contact between the seal fins 62 and the corresponding breathable spacers 4 b and between the seal fins 2 a 1 and the corresponding breathable spacers 4 a .
  • the rotor 2 a can be rotated without the influence of the rotational resistance increased by the contact between the seal fins 62 and the corresponding breathable spacers 4 and between the seal fins 2 a 1 and the corresponding breathable spacers 4 .
  • the biasing force of the plurality of return springs 66 it is only necessary for the biasing force of the plurality of return springs 66 to be set so that the piston head 64 can be shifted in the direction coming close to the rotor 2 a by the pressure of the steam St that can rotate the rotor 2 a without undergoing an influence of the rotational resistance increased by the contact between the seal fins 62 and the corresponding breathable spacers 4 b and between the seal fins 2 a 1 and the corresponding breathable spacers 4 a.
  • the steam St flowing through the inside of the steam turbine 2 expands and reduces in pressure from the upstream toward the downstream. Therefore, the return springs 66 installed in the labyrinth seal device 60 of the stator blade 2 c may be configured to have respective biasing forces that are gradually decreased as the flow of the steam St goes toward the downstream side.
  • the labyrinth seal device 60 may be such that the number of the seal base-plates 61 is not limited to six but seven or more seal base-plates 61 are provided along the circumferential direction. Alternatively, the labyrinth seal device 60 may be provided with five or less seal base-plates 61 along the circumferential direction.
  • the seal fins 62 on the seal base-plate 61 side are not in contact with the corresponding breathable spacers 4 b on the rotor 2 a side.
  • the seal fins 2 a 1 on the rotor 2 a side are not in contact with the corresponding breathable spacers 4 a on the seal base-plate 61 side.
  • the seal fins 62 are in contact with the corresponding breathable spacers 4 b and the seal fins 2 a 1 are in contact with the corresponding breathable spacers 4 a .
  • the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a is improved.
  • the turbine efficiency of the steam turbine 2 is improved.
  • the steam St with high pressure can efficiently rotate the rotor 2 a without undergoing an influence of the rotational resistance increased by the contact between the seal fins 62 and the corresponding breathable spacers 4 b and between the seal fins 2 a 1 and the corresponding breathable spacers 4 a.
  • the plurality of breathable spacers 4 are attached to the rotor 2 a and the labyrinth seal device 60 .
  • the seal base-plate 61 constituting part of the labyrinth seal device 60 is provided on the nozzle diaphragm inner-ring 70 so as to be shiftable in the direction coming close to or moving away from the rotor 2 a .
  • the configuration of the invention is not limited to these.
  • Examples of the labyrinth seal device 60 include a high-low labyrinth seal device in addition to the device shaped as illustrated in FIG. 3 .
  • the present invention can be applied to also the high-low labyrinth seal device.
  • a high-low labyrinth seal device 60 a is provided with a seal base-plate 61 on a nozzle diaphragm inner-ring 70 .
  • the seal base-plate 61 is provided with seal fins 62 projecting upright along the circumferential direction and shiftably in a direction coming close to or moving away from a rotor 2 a .
  • the rotor 2 a is formed with projecting portions 2 a 3 along the circumferential direction on the outer circumference thereof.
  • the seal fins 62 on the seal base-plate 61 side are each arranged to face a corresponding one of the projecting portions 2 a 3 and recessed portions 2 a 4 of the rotor 2 a , each of the recessed portions 2 a 4 being formed between the projecting portions 2 a 3 .
  • the labyrinth seal device 60 a is configured to include a pressurizing chamber 71 , a steam passage 72 , a piston head 64 , a piston body 65 , and a plurality of return springs 66 circumferentially arranged in two lines.
  • breathable spacers 4 b are attached to the corresponding projecting portions 2 a 3 and recessed portions 2 a 4 formed on the rotor 2 a so as to face the corresponding seal fins 62 on the seal base-plate 61 side.
  • the attachment of the breathable spacers 4 b as described above can improve the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a.
  • a seal structure including the labyrinth seal device 60 a and the breathable spacers 4 b on the rotor 2 a side are assembled into the steam turbine 2 (see FIG. 1 ).
  • the high-low labyrinth seal device 60 a illustrated in FIG. 6 may be configured such that the breathable spacers 4 b are attached to either one of the projecting portions 2 a 3 and recessed portions 2 a 4 of the rotor 2 a.
  • the seal base-plate 61 can be installed on the nozzle diaphragm inner-ring 70 shiftably in a direction coming close to or moving away from the rotor 2 a.
  • the seal fins 62 provided on the stator blade 2 c (see FIG. 2 ) which is a fixed portion can be shiftable in a direction coming close to or moving away from the rotor 2 a which is a rotating portion.
  • steam St passes through the steam passage 72 and flows into the pressurizing chamber 71 .
  • the pressure of the steam St may be high and a pressing force adapted to shift the piston head 64 in a direction coming close to the rotor 2 a may be equal to or greater than the biasing force of the plurality of return springs 66 .
  • the piston head 64 is shifted in the direction coming close to the rotor 2 a so that the seal base-plate 61 operating integrally with the piston head 64 via the piston body 65 is shifted in the direction coming close to the rotor 2 a.
  • a high-low labyrinth seal device 60 b may be acceptable in which a plurality of seal fins 2 a 5 are provided on the outer circumference of a rotor 2 a.
  • a seal base-plate 61 a is formed with a plurality of projecting portions 61 a 1 and a plurality of recessed portions 61 a 2 which are circumferentially formed to be lined in the axial direction of the rotor 2 a .
  • breathable spacers 4 a shaped along the circumferential direction are attached to the plurality of corresponding projecting portions 61 a 1 and recessed portions 61 a 2 .
  • the labyrinth seal device 60 b is configured to include the seal base-plate 61 a attached with the breathable spacers 4 a , a pressurizing chamber 71 , a steam passage 72 , a piston head 64 , a piston body 65 , and a plurality of return springs 66 arranged e.g. in the circumferential direction in two lines.
  • the rotor 2 a is provided on the outer circumference with the seal fins 2 a 5 which are provided upright along the circumferential direction at respective positions opposed to the corresponding projecting portions 61 a 1 and recessed portions 61 a 2 of the seal base-plate 61 a.
  • a seal structure including the labyrinth seal device 60 b and the seal fins 2 a 5 on the rotor 2 a side are assembled into the steam turbine 2 (see FIG. 1 ).
  • the seal base-plate 61 a can be installed on the nozzle diaphragm inner-ring 70 shiftably in a direction coming close to or moving away from the rotor 2 a.
  • the breathable spacers 4 a provided on the stator blade 2 c (see FIG. 2 ) which is a fixed portion can be shiftable in a direction coming close to or moving away from the rotor 2 a which is a rotating portion.
  • steam St passes through the steam passage 72 and flows into the pressurizing chamber 71 .
  • the pressure of the steam St may be high and a pressing force adapted to shift the piston head 64 in a direction coming close to the rotor 2 a may be equal to or greater than the biasing force of the plurality of return springs 66 .
  • the piston head 64 is shifted in the direction coming close to the rotor 2 a so that the seal base-plate 61 a operating integrally with the piston head 64 via the piston body 65 is shifted in the direction coming close to the rotor 2 a.
  • the labyrinth seal device 60 b can be configured such that the high-low seal base-plate 61 a is provided on the nozzle diaphragm inner-ring 70 shiftably in the direction coming close to or moving away from the rotor 2 a .
  • the labyrinth seal device 60 b can produce the same effect as that of the labyrinth seal device 60 illustrated in FIG. 3 .
  • the present embodiment can be applied to a labyrinth seal device installed between the nozzle diaphragm outer-ring 80 (see FIG. 2 ) and the rotor blades 2 b (see FIG. 2 ).
  • a cover 2 g is provided at the distal ends of the rotor blades 2 b to reduce the clearance between the rotor blades 2 b and the nozzle diaphragm outer-ring 80 (see FIG. 2 ).
  • the cover 2 g is provided with a plurality of seal fins 2 g 1 .
  • the cover 2 g is provided at the distal ends of the rotor blades 2 b so as to extend circumferentially annularly.
  • the seal fins 2 g 1 are provided on the cover 2 g so as to extend upright along the circumferential direction.
  • Seal base-plates 91 are installed on the nozzle diaphragm outer-ring 80 so as to face the cover 2 g provided on the rotor blades 2 b.
  • the nozzle diaphragm outer-ring 80 on the rotor blade 2 b side is formed to extend in the circumferential direction.
  • e.g. six seal base-plates 91 equally divided in the circumferential direction are installed between the nozzle diaphragm outer-ring 80 and the rotor blades 2 b so as to surround the rotor blades 2 b.
  • breathable spacers 4 a are circumferentially attached to one seal base-plate 91 on the rotor blade 2 b side.
  • the seal fins 2 g 1 are provided on the cover 2 g at respective positions opposed to the corresponding breathable spacers 4 a.
  • all the seal base-plates 91 are installed on the nozzle diaphragm outer-ring 80 shiftable in a direction coming close to or moving away from the rotor blades 2 b , i.e., in the rotational-radial direction of the rotor blades 2 b.
  • the seal base-plate 91 is of e.g. a high-low-type. Specifically, the seal base-plate 91 is formed with a plurality of projecting portions 91 a and a plurality of recessed portions 91 b .
  • the projecting portions 91 a and the recessed portions 91 b are shaped to extend along the rotational direction of the rotor blade 2 b , i.e., in the circumferential direction and are formed in line in the axial direction of the rotor 2 a (see FIG. 2 ).
  • the breathable spacers 4 a are attached to the corresponding projecting portions 91 a and recessed portions 91 b so as to be shaped in the circumferential direction.
  • the breathable spacers 4 a provided for the casing 2 d (see FIG. 2 ) which is a fixed portion can be shifted in a direction coming close to or moving away from the rotor blade 2 b which is a rotating portion.
  • the Seal fins 2 g 1 are circumferentially installed on the cover 2 g of the rotor blade 2 b to extend upright at respective positions opposed to the corresponding projecting portions 91 a and recessed portions 91 b of the seal base-plate 91 .
  • the nozzle diaphragm outer-ring 80 is provided with a hollow pressurizing chamber 81 .
  • the hollow pressurizing chamber 81 is internally provided with a piston head 92 reciprocating in a direction coming close to or moving away from the rotor blade 2 b .
  • the piston head 92 is elastically supported by a plurality of return springs 94 (biasing means) circumferentially arranged, e.g., in two lines. In this way, the piston head 92 is biased by the return springs 94 in a direction moving away from the rotor blade 2 b.
  • the number of the return springs 94 may be set appropriately.
  • the pressurizing chamber 81 is configured to communicate with the outside of the nozzle diaphragm outer-ring 80 through a steam passage 82 . Steam St flowing through the outside of the nozzle diaphragm outer-ring 80 flows into the pressurizing chamber 81 . When the pressure of the steam St is applied to the piston head 92 , the piston head 92 is shifted in a direction coming close to the rotor blade 2 b.
  • the piston head 92 is provided with a piston body 93 .
  • the piston body 93 extends from the pressurizing chamber 81 toward the rotor blade 2 b and has an end portion terminating at the outside of the nozzle diaphragm outer-ring 80 .
  • the seal base-plate 91 is attached to the end portion.
  • the piston body 93 may be formed integrally with the piston head 92 , for example.
  • a method of attaching the seal base-plate 91 to the piston body 93 is not restrictive.
  • the seal base-plate 91 may be secured to the piston body 93 by means of screws not illustrated.
  • a movable portion is configured to include the piston head 92 , the piston body 93 , and the seal base-plate 91 .
  • the labyrinth seal device 90 in the present embodiment is configured to include the seal base-plate 91 , the piston head 92 , the piston body 93 , the plurality of return springs 94 , the pressurizing chamber 81 , and the steam passage 82 .
  • a seal structure including the labyrinth seal device 90 and the seal fins 2 g 1 on the rotor blade 2 b side is assembled into the steam turbine 2 (see FIG. 1 ).
  • the seal base-plate 91 When the piston head 92 of the labyrinth seal device 90 is supported by the biasing force of the return springs 94 at a position away from the rotor blade 2 b , the seal base-plate 91 is shifted to a position away from the rotor blade 2 b . In this state, the breathable spacers 4 a on the seal base-plate 91 side are not in contact with the corresponding seal fins 2 g 1 , opposed thereto, on the cover 2 g side of the rotor blades 2 b . Thus, a clearance is defined between the breathable spacers 4 a and the corresponding seal fins 2 g 1 .
  • the pressure of the steam St flowing into the pressurizing chamber 81 causes a pressing force adapted to shift the piston head 92 in a direction coming close to the rotor blade 2 b . If this pressing force is smaller than the biasing force of the plurality of return springs 94 , the return springs 94 support the piston head 92 at a position away from the rotor blade 2 b.
  • the seal base-plate 91 When the piston head 92 is supported at a position away from the rotor blade 2 b by the biasing force of the return springs 94 , the seal base-plate 91 is shifted to a position away from the rotor blade 2 b . In this state, the breathable spacers 4 a on the seal base-plate 91 side are not in contact with the corresponding seal fins 2 g 1 , opposed thereto, on the cover 2 g side of the rotor blade 2 b . Thus, a clearance is defined between the breathable spacers 4 a and the corresponding seal fins 2 g 1 .
  • the pressure of the steam St flowing into the steam turbine 2 (see FIG. 1 ) is increased, also the pressure of the steam St flowing into the pressurizing chamber 81 is increased.
  • the pressure of the steam St causes a pressing force adapted to shift the piston head 92 in the direction coming close to the rotor blade 2 b . If this pressing force becomes equal to or greater than the biasing force of the return springs 94 , the piston head 92 is shifted in the direction coming close to the rotor blade 2 b by the pressure of the steam St.
  • the seal base-plate 91 connected to the piston head 92 via the piston body 93 is shifted in the direction coming close to the rotor blade 2 b.
  • the biasing force of the plurality of return springs 94 it is only necessary for the biasing force of the plurality of return springs 94 to be set so that the piston head 92 can be shifted in the direction coming close to the rotor blade 2 b by the pressure of the steam St that can rotate the rotor 2 a without undergoing an influence of the rotational resistance increased by the contact between the seal fins 2 g 1 and the breathable spacers 4 a.
  • the return springs 94 may be configured to have respective biasing forces that are gradually decreased as the flow of the steam St goes toward the downstream side.
  • the number of the seal base plates 91 is not limited to six.
  • the labyrinth seal device 90 circumferentially provided with seven or more seal base-plates 91 may be acceptable.
  • the labyrinth seal device 90 circumferentially provided with five or less seal base-plates 91 may be acceptable.
  • the breathable spacers 4 a on the seal base-plate 91 side are not in contact with the corresponding seal fins 2 g 1 on the cover 2 g side of the rotor blade 2 b .
  • a clearance is defined between the breathable spacers 4 a and the corresponding seal fins 2 g 1 so that the rotational resistance against the rotation of the rotor blade 2 b (the rotating portion) is reduced.
  • the rotor 2 a is efficiently rotated by the steam St with low pressure to smoothly start up the steam turbine 2 .
  • the labyrinth seal device 90 illustrated in FIG. 9 is configured such that the plurality of breathable spacers 4 a are attached to the seal base-plate 91 and the plurality of seal fins 2 g 1 are provided on the cover 2 g .
  • the labyrinth seal device 90 may be configured such that the seal fins are provided on the seal base-plate 91 and the breathable spacers are attached to the cover 2 g.
  • the labyrinth seal device 90 may be configured such that the plurality of seal fins are provided on both the seal base-plate 91 and the cover 2 g .
  • the breathable spacers are configured to be attached to the cover 2 g at respective positions opposed to the corresponding seal fins on the seal base-plate 91 side and to the seal base-plate 91 at respective positions opposed to the corresponding seal fins on the cover 2 g side.
  • the seal base-plate 61 is biased by the return springs 66 elastically supporting the piston head 64 in the pressurizing chamber 71 in the direction moving away from the rotor 2 a .
  • respective piston bodies 65 of adjacent seal base-plates 61 may circumferentially be connected to each other via compression springs 66 a (biasing means) as illustrated in FIG. 10 .
  • the compression springs 66 a are installed between the adjacent piston bodies 65 in a compressed state so as to bias the piston body 65 in a direction moving the adjacent piston bodies 65 away from each other.
  • One piston body 65 is elastically supported by the compression springs 66 a in a state shifted to a position away from the rotor 2 a .
  • the seal base-plate 61 is attached to the piston body 65 so that the seal base-plate 61 is supported at a position away from the rotor 2 a.
  • the labyrinth seal device 60 illustrated in FIG. 3 is configured such that the piston head 64 is driven by the pressure of the steam St flowing through the steam turbine 2 (see FIG. 1 ).
  • the following configuration illustrated in FIG. 11 may be acceptable.
  • the piston head 64 is shifted in a direction coming close to the rotor 2 a by the high pressure of steam (driving steam) for driving the piston head 64 , the steam flowing into the pressurizing chamber 71 from a high-pressure steam supply source 102 .
  • a labyrinth seal device 60 c illustrated in FIG. 11 is configured to include a valve control device 100 , an operating condition detecting device 101 , the high-pressure steam supply source 102 , and an electromagnetic valve 103 in addition to the labyrinth seal device 60 illustrated in FIG. 3 .
  • a seal structure including the labyrinth seal device 60 c and the plurality of seal fins 2 a 1 and plurality of breathable spacers 4 b on the rotor 2 a 1 side is assembled into the steam turbine 2 (see FIG. 1 ).
  • the high-pressure steam supply source 102 is connected to the pressurizing chamber 71 via the electromagnetic valve 103 . Further, the valve control device 100 for controlling the opening/closing of the electromagnetic valve 103 is provided.
  • the valve control device 100 is configured to control the opening/closing of the electromagnetic valve 103 on the basis of the operating condition of the steam turbine 2 (see FIG. 1 ).
  • the valve control device 100 is provided with the operating condition detecting device 101 for detecting the operating condition of the steam turbine 2 .
  • valve control device 100 can shift a movable portion including the piston head 64 , the piston body 65 , and the seal base-plate 61 in a direction coming close to the rotor 2 a on the basis of the operating condition of the steam turbine 2 .
  • a drive device is configured to include the pressurizing chamber 71 , the valve control device 100 , the high-pressure steam supply source 102 , and the electromagnetic valve 103 .
  • the operating condition of the steam turbine 2 (see FIG. 2 ) is detected based on e.g. the rotation speed of the rotor 2 a .
  • the operating condition detecting device 101 is a rotation speed detecting device for detecting the rotation speed of the rotor 2 a.
  • the operating condition detecting device which is the rotation speed detecting device detects the rotation speed of the rotor 2 a and converts it to a detection signal, which is sent to the valve control device 100 .
  • the valve control device 100 calculates the rotation speed of the rotor 2 a on the basis of the detection signal supplied from the operating condition detecting device 101 (the rotation speed detecting device).
  • valve control device 100 sends a control signal to the electromagnetic valve 103 for closing.
  • the predetermined rotation speed in this case may appropriately set based on the performance or the like of the steam turbine 2 (see FIG. 1 ).
  • the electromagnetic valve 103 is closed based on a control signal sent from the valve control device 100 to cut off the inflow of driving steam to the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • the seal base-plate 61 is shifted in the direction moving away from the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side are not in contact with the corresponding breathable spacers 4 b on the rotor 2 a side.
  • the breathable spacers 4 a on the seal base-plate 61 side are not in contact with the corresponding seal fins 2 a 1 on the rotor 2 a side.
  • rotational resistance against the rotation of the rotor 2 a is reduced.
  • valve control device 100 sends a control signal to the electromagnetic valve 103 for opening.
  • the electromagnetic valve 103 is opened based on the control signal sent from the valve control device 100 , so that the driving steam flows into the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • the piston head 64 is shifted in a direction coming close to the rotor 2 a by the pressure of the driving steam flowing into the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • the seal base-plate 61 is shifted in the direction coming close to the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side come into contact with the corresponding breathable spacers 4 b on the rotor 2 a side.
  • the seal fins 2 a 1 on the rotor 2 a side come into contact with the corresponding breathable spacers 4 a on the seal base-plate 61 side.
  • the valve control device 100 closes the electromagnetic valve 103 to bring the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side into non-contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side are brought into non-contact with each other. In this way, the rotational resistance against the rotation of the rotor 2 a is reduced.
  • the rotor 2 a is efficiently rotated by the steam St and the steam turbine 2 is smoothly started up.
  • the valve control device 100 opens the electromagnetic valve 103 to bring the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side into contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side are brought into contact with each other.
  • the steam turbine 2 is improved in the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a , thereby improving turbine efficiency.
  • the pressure of the driving steam is pressure that can shift the piston head 64 in a direction coming close to the rotor 2 a against the biasing force of the return springs 66 .
  • a configuration may be acceptable in which the operating condition of the steam turbine 2 is detected by use of e.g. the pressure of the steam St.
  • the operating condition detecting device 101 is a pressure detecting device for detecting the pressure of the steam St.
  • the operating condition detecting device 101 which is the pressure detecting device detects the pressure of steam St flowing through the steam turbine 2 (see FIG. 1 ) and sends a detection signal to the valve control device 100 .
  • the valve control device 100 calculates the pressure of the steam St.
  • valve control device 100 sends a control signal to the electromagnetic valve 103 for closing.
  • the electromagnetic valve 103 is closed based on the control signal sent from the valve control device 100 to cut off the inflow of the driving steam to the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • predetermined pressure value it is only necessary for the predetermined pressure value to be appropriately set based on the performance or the like of the steam turbine 2 (see FIG. 1 ).
  • the piston head 64 is shifted in a direction moving away from the rotor 2 a by the biasing force of the return springs 66 .
  • the seal base-plate 61 is shifted in the direction moving away from the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side are not in contact with each other.
  • the breathable spacers 4 a on the seal base-plate 61 side, and the corresponding seal fins 2 a 1 on the rotor 2 a side are not in contact with each other.
  • the rotational resistance against the rotation of the rotor 2 a is reduced.
  • valve control device 100 sends a control signal to the electromagnetic valve 103 for opening.
  • the electromagnetic valve 103 is opened based on the control signal sent from the valve control device 100 , so that the driving steam flows into the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • the piston head 64 is shifted in a direction coming close to the rotor 2 a by the pressure of the driving steam flowing into the pressurizing chamber 71 from the high-pressure steam supply source 102 .
  • the seal base-plate 61 is shifted in the direction coming close to the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side come into contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side come into contact with each other.
  • the valve control device 100 closes the electromagnetic valve 103 .
  • the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side are brought into non-contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side are brought into non-contact with each other. This reduces the rotational resistance against the rotation of the rotor 2 a .
  • the rotor 2 a is efficiently rotated by the steam St with low-pressure and the steam turbine 2 is smoothly started up.
  • the steam turbine 2 (see FIG. 2 ) is started up and the pressure of the steam St becomes equal to or greater than the predetermined pressure value. Then, the valve control device 100 opens the electromagnetic valve 103 to bring the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side into contact with each other. In addition, this brings the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side into contact with each other.
  • the steam turbine 2 is improved in the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a , thereby improving turbine efficiency.
  • the steam turbine 2 when the pressure of the steam St is lower than the predetermined pressure value, such as during the initial period of start-up or the like, the steam turbine 2 (see FIG. 2 ) is such that the clearance is defined between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a . This reduces rotational resistance against the rotation of the rotor 2 a , so that the rotor 2 a is efficiently rotated by the steam St for smooth start-up.
  • the pressure of the steam St becomes equal to or greater than the predetermined pressure value, the steam turbine 2 is improved in the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a , thereby improving turbine efficiency.
  • the labyrinth seal device 60 c illustrated in FIG. 11 is configured such that the driving steam is allowed to flow into the pressurizing chamber 71 from the high-pressure steam supply source 102 to shift the piston head 64 in a direction coming close to the rotor 2 a .
  • a configuration may be acceptable in which the piston head 64 is shifted in a direction coming close to the rotor 2 a by a driving means such as an actuator or the like not illustrated.
  • the seal structure (see FIG. 9 ) assembled between the nozzle diaphragm outer-ring 80 and the rotor blades 2 b may be made to have the same configuration as that of the seal structure illustrated in FIG. 11 .
  • the steam turbine 2 (see FIG. 1 ) according to the present embodiment has the seal structure assembled between the stator blades 2 c (see FIG. 2 ) which are the fixed portion and the rotor 2 a which is the rotating portion, the seal structure including the labyrinth seal device 60 , the seal fins 2 a 1 on the rotor 2 a side, and the breathable spacers 4 b on the rotor 2 a side, as illustrated in FIG. 3 .
  • seal fins 62 on the seal base-plate 61 side of the labyrinth seal device 60 come into contact with the corresponding breathable spacers 4 b on the rotor 2 a side and the seal fins 2 a 1 on the rotor 2 a side come into contact with the corresponding breathable spacers 4 a on the seal base-plate 61 side.
  • This configuration improves the sealing performance between the stator blades 2 c and the rotor 2 a , thereby producing an excellent effect of suppressing the lowering of turbine efficiency due to leakage steam.
  • the breathable spacer 4 ( 4 a , 4 b ) is formed of breathable metal which is abradable material superior in the easiness of the abrasion.
  • the breathable spacer 4 made of breathable metal can aerate a slight amount of steam St. Therefore, frictional heat resulting from the contact between each of the seal fins 62 and 2 a 1 and the breathable spacer 4 can be cooled by the steam St passing through the breathable spacer 4 . Thus, the breathable spacer 4 can be prevented from having temperature higher than that of the steam St.
  • the breathable spacer 4 will not have temperature higher than that of the steam St.
  • the rotor 2 a and the seal base-plate 61 each of which is attached with the breathable spacer 4 do not have temperature higher than that of the steam St.
  • an excellent effect can be produced in which the rotor 2 a and the seal base-plate 61 are prevented from causing thermal deformation.
  • the spacer made of porous metal is abradable material superior in the easiness of the abrasion. If the seal fins 62 and 2 a 1 each come into contact with the spacer made of porous metal, since the spacer made of porous metal is abraded, the seal fins 62 and 2 a 1 can be prevented from being damaged.
  • pores of the porous metal may sometimes not communicate with each other.
  • the spacer made of porous metal cannot aerate steam St.
  • the frictional heat caused by the contact between each of the seal fins 62 and 2 a 1 and the spacer made of porous metal cannot be cooled by the steam St.
  • the frictional heat caused by the contact between each of the seal fins 62 and 2 a 1 and the breathable spacer 4 can be cooled by the steam St passing through the breathable spacer 4 .
  • the seal base-plate 61 provided with the seal fins 62 and the breathable spacers 4 a is installed on the nozzle diaphragm inner-ring 70 shiftably in a direction coming close to or moving away from the rotor 2 a .
  • the seal fins 62 on the seal base-plate 61 side and the corresponding breathable spacers 4 b on the rotor 2 a side are not in contact with each other.
  • the seal fins 2 a 1 on the rotor 2 a side and the corresponding breathable spacers 4 a on the seal base-plate 61 side are not in contact with each other.
  • the seal fins 62 and 2 a 1 are brought into contact with the corresponding breathable spacers 4 . This can improve the sealing performance between the stator blades 2 c (see FIG. 2 ) and the rotor 2 a . Thus, an excellent effect of preventing the lowering of the turbine efficiency of the steam turbine 2 can be produced.
  • the seal structure including the labyrinth seal device 60 , the plurality of seal fins 2 a 1 , and the plurality of breathable spacers 4 b illustrated in e.g. FIG. 3 can be assembled not only between the nozzle diaphragm inner-ring 70 and the rotor 2 a but also between another fixed portion and another rotating portion such as between the casing 2 d (see FIG. 2 ) and the rotor 2 a.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
US12/769,249 2009-05-01 2010-04-28 Seal Structure and Control Method Therefor Abandoned US20100278645A1 (en)

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JP2009112332A JP5411569B2 (ja) 2009-05-01 2009-05-01 シール構造とその制御方法
JP2009-112332 2009-05-01

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US20090142187A1 (en) * 2007-12-04 2009-06-04 Kenjiro Narita Seals in steam turbine
US20130216362A1 (en) * 2012-02-06 2013-08-22 Mitsubishi Heavy Industries, Ltd. Seal structure and rotating machine equipped therewith
DE102013017710A1 (de) * 2013-10-24 2015-04-30 Man Diesel & Turbo Se Dichtungssystem
US20150300190A1 (en) * 2012-10-18 2015-10-22 Mitsubishi Hitachi Power Systems, Ltd. Rotating machine
US20150369075A1 (en) * 2012-12-13 2015-12-24 Mitsubishi Hitachi Power Systems, Ltd. Rotating fluid machine
US10215044B2 (en) * 2014-08-08 2019-02-26 Siemens Energy, Inc. Interstage seal housing optimization system in a gas turbine engine
US11319825B2 (en) 2016-02-16 2022-05-03 Mitsubishi Power, Ltd. Sealing device and rotary machine
US20220195882A1 (en) * 2020-12-18 2022-06-23 General Electric Company Turbomachine clearance control using brush seals having magnetically responsive filaments

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JP5427798B2 (ja) * 2011-01-14 2014-02-26 株式会社日立製作所 蒸気タービンのシール構造
ITCO20110013A1 (it) * 2011-03-29 2012-09-30 Nuovo Pignone Spa Sistemi di chiusura per turboespansori da usare in cicli rankine organici
JP5717566B2 (ja) * 2011-07-13 2015-05-13 株式会社東芝 シール装置、および蒸気タービン
CN102619577B (zh) * 2012-04-06 2015-06-10 东南大学 一种抑制叶顶间隙泄漏和减小汽流激振力装置
JP5892880B2 (ja) * 2012-07-03 2016-03-23 三菱日立パワーシステムズ株式会社 回転機械のシール構造及び回転機械
CN103075204B (zh) * 2013-01-25 2015-11-18 潍坊雷诺特动力设备有限公司 汽轮机后汽封装置
CN104654786B (zh) * 2015-02-10 2016-08-31 烽火通信科技股份有限公司 一种预热炉的运动密封件
JP2018035717A (ja) * 2016-08-30 2018-03-08 三菱日立パワーシステムズ株式会社 シール装置用セグメント並びにそれを備えるタービンロータ及びタービン
FR3058495B1 (fr) * 2016-11-09 2019-06-28 Safran Aircraft Engines Dispositif d'etancheite a double etagement, joint labyrinthe et lechette mobile

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