# US 2022/0034236 A1 · Internal turbomachine casing having improved thermal insulation

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- Number: US 2022/0034236 A1
- Document ID: US20220034236A1
- Status: Published application
- Kind: A1
- Application number: 17/278,700
- Filed: 2019-09-17
- Published: 2022-02-03
- Earliest claimed: 2018-09-24
- Assignees: Safran Aircraft Engines
- Applicants: Safran Aircraft Engines
- Inventors: Christophe SCHOLTES
- Web page: https://patentgrep.com/patent/US20220034236A1

## CPC

- F01D 25/145: {Thermally insulated casings}
- B33Y 80/00: Products made by additive manufacturing
- F01D 11/122: {with erodable or abradable material (blades having cutting or grinding tips F01D5/20)}
- F01D 11/18: using stator or rotor components with predetermined thermal response, e.g. selective insulation, thermal inertia, differential expansion
- F05D 2220/32: in gas turbines
- F05D 2230/31: Layer deposition
- F05D 2240/11: Shroud seal segments
- F05D 2250/282: cubic pattern
- F05D 2250/283: honeycomb
- F05D 2260/231: Preventing heat transfer
- F05D 2300/514: Porosity
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An internal casing ferrule for a turbomachine, centered on a longitudinal central axis, which includes: a main body centered on this axis, with two ends, delimited by surfaces that are radially inner and outer relative to this axis; a thermal porous-structure insulation envelope having a volumetric porosity ≥50%, which includes: a lateral portion entirely covering the two ends; when viewed in section transversely to this axis, exterior and interior portions entirely covering, respectively, the radially outer and inner surfaces of the main body; and a protective envelope which at least partially covers the envelope and which includes, when viewed in section transversely to this axis, radially outer and inner protective portions, respectively covering, at least in part, the exterior and interior portions.

## Claims

### Claim at position 1

1-13. (canceled)

### Claim 14

Internal casing ferrule for a turbomachine, the ferrule being centred on a longitudinal central axis, wherein the internal casing ferrule includes:
a main body, that is centred on the longitudinal central axis, that includes two longitudinal ends and that is delimited by a radially internal surface and a radially external surface relative to the longitudinal central axis;
a thermal insulation envelope, that includes:
a lateral covering portion entirely covering the longitudinal ends of the main body;
along a section transversal to the longitudinal central axis, an exterior covering portion entirely covering the radially external surface of the main body;
along a section transversal to the longitudinal central axis, an interior covering portion entirely covering the radially internal surface of the main body;
the lateral portion connecting the interior and exterior portions; and
a protective envelope, that at least partially covers the thermal insulation envelope and that includes, along a section transversal to the longitudinal central axis:
a radially external protective portion at least partially covering the exterior covering portion; and
a radially internal protective portion at least partially covering the interior covering portion;
and wherein the thermal insulation envelope has a porous structure with a volumetric porosity greater than or equal to 50%.

### Claim 15 (depends on 14)

Ferrule according to claim 14, wherein the main body and the exterior and interior covering portions each extend over 360° around the longitudinal central axis.

### Claim 16 (depends on 14)

Ferrule according to claim 14, wherein the main body and the exterior and interior covering portions each extend around the longitudinal central axis over an identical angular sector less than 360°.

### Claim 17 (depends on 16)

Ferrule according to claim 16, wherein the main body has two opposite circumferential ends and the thermal insulation envelope further includes an intermediate covering portion that connects the exterior and interior covering portions and that entirely covers each opposite circumferential end of the main body.

### Claim 18 (depends on 17)

Ferrule according to claim 17, wherein the protective envelope further comprises an intermediate protective portion that connects the radially external and internal protective portions and that entirely covers the intermediate covering portion.

### Claim 19 (depends on 14)

Ferrule according to claim 14, wherein the radially external and internal protective portions of the protective envelope entirely cover, respectively, the exterior covering portion and the interior covering portion of the thermal insulation envelope.

### Claim 20 (depends on 14)

Ferrule according to claim 14, wherein the protective envelope has a volumetric porosity of less than 5%.

### Claim 21 (depends on 14)

Ferrule according to claim 14, wherein the thermal insulation envelope has a cellular structure, preferably a honeycomb cellular structure, or a lattice structure.

### Claim 22 (depends on 14)

Ferrule according to claim 14, wherein the main body, the thermal insulation envelope and the protective envelope are made in a single piece by additive manufacturing to form a single-block and monolithic part.

### Claim 23 (depends on 14)

Ferrule according to claim 14, comprising a strip of abradable material that is integrated into the ferrule by being made directly in the protective envelope.

### Claim 24 (depends on 14)

Internal turbomachine casing, comprising at least two ferrules according to claim 14, arranged axially adjacent to one another.

### Claim 25 (depends on 24)

Turbomachine equipped with an internal casing according to claim 24.

### Claim 26 (depends on 25)

Turbomachine according to claim 25, comprising movable blades and wherein at least one ferrule comprises a strip of abradable material that is added onto said at least one ferrule in line with the movable blades.