Turbine wheel cover-plate mounted gas turbine interstage seal

Patent metadata

Field	Value
Publication number	US-2016153302-A1
Application number	US-201414556305-A
Country	US
Kind code	A1
Filing date	Dec 1, 2014
Priority date	Dec 1, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

A sealing system for a multi-stage turbine includes multiple first interstage seal subsystems disposed circumferentially about a rotor wheel shaft of the multi-stage turbine and extending axially between a first turbine stage and a second turbine stage of the multi-stage turbine. Each of the first interstage seal subsystems includes multiple near flow path seal segments. The first interstage seal subsystem also includes a forward coverplate disposed axially between a first turbine wheel of the first turbine stage and the near flow path seal segment and an aft coverplate disposed axially between the near flow path seal segment and a second turbine wheel of the second turbine stag. Further, each of the forward coverplate and the aft coverplate extends radially to a first stage bucket and a second stage bucket respectively.

First claim

1 . A sealing system for a multi-stage turbine, the sealing system comprising:
a plurality of first interstage seal subsystems disposed circumferentially about a rotor wheel shaft of the multi-stage turbine and extending axially between a first turbine stage and a second turbine stage of the multi-stage turbine, wherein each of the plurality of first interstage seal subsystems comprises:
a plurality of near flow path seal segments;
a forward coverplate disposed axially between a first turbine wheel of the first turbine stage and the near flow path seal segment; and
an aft coverplate disposed axially between the near flow path seal segment and a second turbine wheel of the second turbine stage, wherein each of the forward coverplate and the aft coverplate extends radially to a first stage bucket and a second stage bucket respectively.

2 . The sealing system of claim 1 , wherein each of the first turbine wheel and the second turbine wheel comprises a plurality of dovetail slots configured for mounting a plurality of buckets or blades.

3 . The sealing system of claim 2 , wherein a side of the first turbine wheel facing the forward coverplate comprises a wheel rim with a plurality of tab protrusions on an inner diameter of the wheel rim in a radially inward direction.

4 . The sealing system of claim 3 , wherein the forward coverplate comprises a plurality of scalloped L-shaped seats at inner end for enabling radial and circumferential retention when mounted on the side of the first turbine wheel having the plurality of tab protrusions on inner diameter of the wheel rim.

5 . The sealing system of claim 3 , further comprising a first seal wire disposed in a seal wire groove of the forward coverplate and located axially between the forward coverplate and the first stage bucket for isolating the wheel rim of the first turbine wheel from a flow of hot gas path.

6 . The sealing system of claim 3 , further comprising a forward axial retention ring disposed between the plurality of tab protrusions on the inner diameter of the wheel rim of the first turbine wheel and the forward coverplate for locking the forward coverplate with the first turbine wheel.

7 . The sealing system of claim 1 , wherein a side of the second turbine wheel facing the aft coverplate comprises a wheel rim with a plurality of tab protrusions on an inner diameter of the wheel rim in a raidally inward direction.

8 . The sealing system of claim 7 , wherein the aft coverplate comprises a plurality of scalloped L-shaped seats at inner end for enabling radial and circumferential retention when mounted on the side of the second turbine wheel having the plurality of tab protrusions on inner diameter of the wheel rim.

9 . The sealing system of claim 8 , further comprising a second seal wire disposed in a seal wire groove of the aft coverplate and located axially between the aft coverplate and the second stage bucket for isolating the wheel rim of the second turbine wheel from a flow of hot gas path.

10 . The sealing system of claim 8 , further comprising an aft axial retention ring disposed between the plurality of tab protrusions on the inner diameter of the wheel rim the second turbine wheel and the aft coverplate for locking the aft coverplate with the second turbine wheel.

11 . The sealing system of claim 1 , wherein the aft coverplate comprises an angel wing structure at an outward end of the aft coverplate.

12 . The sealing system of claim 1 , wherein the aft coverplate comprises a retention hook portion located on a side facing the second turbine wheel for axial retention with each of a bucket retention hook of the second stage buckets.

13 . The sealing system of claim 1 , wherein the near flow path seal segment comprises an angel wing structure at an outward end towards a forward side of the near flow path seal segment.

14 . The sealing system of claim 1 , wherein a portion of the forward coverplate mounted on the first turbine wheel, extends part way along a bucket shank of the first stage bucket, forms a hook and wherein the near flow path seal segment is mounted on the hook of the forward coverplate towards a forward side.

15 . The sealing system of claim 1 , wherein aft coverplate comprises a receiving structure between a plurality of angel wing lands for constraining the near flow path seal segment at the aft side.

16 . The sealing system of claim 15 , wherein the receiving structure comprises a plurality of recessed roundcuts that allows locking with a plurality of protruding tabs located underside of the near flow path seal segment at the aft side for circumferentially constraining the near flow path seal segment.

17 . The sealing system of claim 1 , further comprising a plurality of intersegment spline seals located at both sides of each of the plurality of near flow path seal segment for preventing intersegment gap leakages.

18 . The sealing system of claim 1 , wherein the aft coverplate extends to a plurality of flange bolts disposed on a plurality of buckets for allowing bucket cooling flow supply conduits.

19 . A method of assembling a sealing system of a multi-stage turbine having a plurality of first stage buckets and a plurality of second stage buckets on a first turbine wheel and a second turbine wheel respectively, the method comprising:
installing each of the plurality of second stage buckets onto each of a plurality of dovetail slots of the second turbine wheel; disposing an aft seal wire in a seal wire groove of each of the plurality of aft coverplates; mounting a mating portion of each of the plurality of aft coverplates on the extended plurality of second stage buckets by moving the each of the plurality of aft coverplates axially and then radially outward such that a plurality of bucket retention hooks are fully engaged with the mating portion of the aft coverplate, wherein the mating portion comprises a retention hook structure; sliding the plurality of second stage buckets along with the aft coverplate on the plurality of dovetail slots; disposing an aft axial retention ring between a plurality of tab protrusions on an inner diameter of the wheel rim of the second turbine wheel and the aft coverplate for locking the aft coverplate with the second turbine wheel; mounting a plurality of scalloped L-shaped seats at inner end of each of the plurality of forward coverplates with a plurality of tab protrusions on inner diameter of a wheel rim of the first turbine wheel such that the plurality of scalloped L-shaped seats are completely engaged with the plurality of tab protrusions; disposing a forward axial retention ring between a plurality of tab protrusions on an inner diameter of the wheel rim of the first turbine wheel and the forward coverplate for locking the forward coverplate with the first turbine wheel; mounting a forward end and an aft end of each of a plurality of near flow path seal segments on a hook portion of the forward coverplate and a receiving structure of the aft coverplate; and installing each of the plurality of first stage buckets onto each of a plurality of dovetail slots of the first turbine wheel.

20 . A gas turbine system comprising:
a plurality of first stage buckets attached to a first turbine wheel; a plurality of second stage buckets attached to a second turbine wheel; a plurality of first interstage seal subsystems disposed circumferentially about a rotor wheel shaft of the gas turbine and extending axially between a first turbine stage and a second turbine stage of the gas turbi

Assignees

• Gen Electric

Inventors

• Samudrala Omprakash
• Sevincer Edip
• Webster Jonathan Michael
• Casanova Fernando Jorge

Classifications

• F01D11/001 Primary

  for sealing space between stator blade and rotor · CPC title

• F02C7/28

  Arrangement of seals · CPC title

• F01D5/3007

  of axial insertion type · CPC title

• F01D11/003 Primary

  by packing rings; Mechanical seals · CPC title

• F05D2230/60

  Assembly methods · CPC title