# US 8,784,052 B2 · Ceramic gas turbine shroud

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- Number: US 8,784,052 B2
- Document ID: US8784052B2
- Status: Granted
- Kind: B2
- Application number: 12/776,673
- Filed: 2010-05-10
- Published: 2011-11-10
- Granted: 2014-07-22
- Earliest claimed: 2010-05-10
- Assignees: Hamilton Sundstrand Corporation
- Applicants: Jun Shi; Kevin E. Green
- Inventors: Jun Shi; Kevin E. Green
- Web page: https://patentgrep.com/patent/US8784052B2

## CPC

- F01D 11/08: for sealing space between rotor blade tips and stator (specially-shaped blade tips therefor F01D5/20)
- F01D 25/26: Double casings; Measures against temperature strain in casings
- F01D 25/28: Supporting or mounting arrangements, e.g. for turbine casing
- F05D 2240/11: Shroud seal segments
- F05D 2260/94: Functionality given by mechanical stress related aspects such as low cycle fatigue [LCF] of high cycle fatigue [HCF]
- F05D 2260/941: particularly aimed at mechanical or thermal stress reduction
- F05D 2300/21: Oxide ceramics
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An example gas turbine engine shroud includes a first annular ceramic wall having an inner side for resisting high temperature turbine engine gasses and an outer side with a plurality of radial slots. A second annular metallic wall is positioned radially outwardly of and enclosing the first annular ceramic wall and has a plurality of tabs in communication with the slot of the first annular ceramic wall. The tabs of the second annular metallic wall and slots of the first annular ceramic wall are in communication such that the first annular ceramic wall and second annular metallic wall are affixed.

## Claims

### Claim 1

A gas turbine engine shroud comprising:
a first annular ceramic wall including an inner side for resisting high temperature turbine engine gases and an outer side with a plurality of radial slots; and
a second annular metallic wall positioned radially outward of and enclosing the first annular ceramic wall and including a plurality of radial tabs in communication with the slot of the first annular ceramic wall such that the first annular ceramic wall and second annular metallic wall are affixed, wherein at least one of the tabs includes an opening through the at least one of the tabs to increase ductility of the at least one of the tabs, wherein the first annular ceramic wall encloses rotatable turbine blades and the first annular ceramic wall surrounds stator vanes, wherein the opening extends into the second annular metallic wall.

### Claim 2 (depends on 1)

The gas turbine engine shroud of claim 1, wherein the at least one of the tabs are distinct from and attached to the second annular metallic wall.

### Claim 3 (depends on 1)

The gas turbine engine shroud of claim 1, wherein at least one slot is in communication with a spring strap attached to the second annular metallic wall.

### Claim 4 (depends on 3)

The gas turbine engine shroud of claim 3, wherein the spring strap is attached to the second annular metallic wall in a first location by welding and in a second location by one of riveting or bolting.

### Claim 5 (depends on 3)

The gas turbine engine shroud of claim 3, wherein the spring strap is also in communication with at least one tab of the second annular metallic wall.

### Claim 6 (depends on 1)

The gas turbine engine shroud of claim 1, wherein the opening is a circular hole.

### Claim 7 (depends on 1)

The gas turbine engine shroud of claim 1, wherein the opening is a rectangular hole.

### Claim 8

A gas turbine engine shroud comprising:
a first annular ceramic wall including an inner side for resisting high temperature turbine engine gases and an outer side with a plurality of radial slots; and
a second annular metallic wall positioned radially outward of and enclosing the first annular ceramic wall and including a plurality of radial tabs in communication with the slot of the first annular ceramic wall such that the first annular ceramic wall and second annular metallic wall are affixed, wherein at least one of the tabs includes an opening through the at least one of the tabs to increase ductility of the at least one of the tabs, wherein the first annular ceramic wall encloses rotatable turbine blades and the first annular ceramic wall surrounds stator vanes,
wherein at least one slot is in communication with a spring strap attached to the second annular metallic wall, wherein the spring strap has the same profile as the shape of the slot.