# US 2014/0191476 A1 · Labyrinth seal

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- Number: US 2014/0191476 A1
- Document ID: US20140191476A1
- Status: Published application
- Kind: A1
- Application number: 14/202,571
- Filed: 2014-03-10
- Published: 2014-07-10
- Earliest claimed: 2011-09-12
- Assignees: Ansaldo Energia IP UK Limited
- Applicants: ALSTOM Technology Ltd.
- Inventors: Cyrille Bricaud; Ulrich Robert Steiger; Axel Heidecke; Carlos Simon-Delgado
- Web page: https://patentgrep.com/patent/US20140191476A1

## CPC

- F01D 11/02: by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08)
- F01D 11/025: {Seal clearance control; Floating assembly; Adaptation means to differential thermal dilatations}
- F16J 15/445: {with means for adjusting the clearance}
- F16J 15/4472: {with axial path}
- F05D 2300/50212: dissimilar
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A labyrinth seal is provided for sealing the annular interspace between the rotor and the stator of a steam turbine or gas turbine. The labyrinth seal includes a multiplicity of sealing strips which are arranged in series in the axial direction and fastened on the stator and project into the interspace. The sealing strips interact, with sealing effect, with rotor-side sealing elements which are arranged in a staggered manner. An improved sealing effect is achieved by the sealing strips in the cold installed state being offset in relation to a symmetrical position, wherein the offset has the reverse direction and the same amount as the distance by which the sealing strip is displaced relative to adjacent rotor-side sealing elements as a result of thermal expansions of the stationary and rotating components and support structure when being heated from the cold installed state to a hot steady-state operating condition.

## Claims

### Claim 1

A labyrinth seal for sealing the annular interspace between a stationary part and a rotating part of a steam turbine or gas turbine, comprising a multiplicity of sealing strips which are arranged in series in the axial direction, are fastened on the stationary part and project into the interspace, which sealing strips interact, with sealing effect, with rotor-side sealing elements which are arranged in a staggered manner, wherein the sealing strips in the cold installed state are offset in relation to a symmetrical position, wherein the offset has the reverse direction and the same amount as the distance by which the sealing strip is displaced relative to adjacent rotor-side sealing elements as a result of thermal expansions of the stationary support structure and rotating components when being heated from a cold installed state to a hot steady-state operating condition.

### Claim 2 (depends on 1)

The labyrinth seal of claim 1, wherein the cold installed state the distance (b) from the rotor-side sealing elements to the nearest sealing strip of the stationary part is between 0.2 and 0.8 times the distance (a) to the farther sealing strip.

### Claim 3 (depends on 1)

The labyrinth seal of claim 1, wherein the rotor-side sealing elements are formed as annular formed projections of the rotating part.

### Claim 4 (depends on 1)

The labyrinth seal of claim 1, wherein the formed projections, between two adjacent rotor-side sealing elements in each case, have an essentially rectangular cross section and extend in the radial direction into the interspace.

### Claim 5 (depends on 1)

The labyrinth seal of claim 1, wherein the formed projections, between two adjacent rotor-side sealing elements in each case, have an intermediate contour with varying diameter in the axial direction, and in that the variation of the outside diameter in the intermediate contour is designed in such a way that during interaction with the respective sealing strip of the stationary part a compensation of thermally induced displacements between rotating part and stationary part is provided.

### Claim 6 (depends on 5)

The labyrinth seal of claim 5, wherein the intermediate contour of the formed projections has a maximum height in the middle between two adjacent rotor-side sealing elements in each case so that during steady-state operation the sealing strips lie in each case opposite this region with maximum height and the free gap between sealing strips and intermediate contour becomes minimal.