# US 11,028,927 B2 · Wide differential pressure range air riding carbon seal

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- Number: US 11,028,927 B2
- Document ID: US11028927B2
- Status: Granted
- Kind: B2
- Application number: 16/265,484
- Filed: 2019-02-01
- Published: 2019-05-30
- Granted: 2021-06-08
- Earliest claimed: 2015-01-12
- Assignees: ROLLS-ROYCE plc
- Applicants: Rolls-Royce Corporation
- Inventors: Nathan A. Lewis
- Web page: https://patentgrep.com/patent/US11028927B2

## CPC

- F16J 15/445: {with means for adjusting the clearance}
- F01D 11/003: {by packing rings; Mechanical seals}
- F01D 11/025: {Seal clearance control; Floating assembly; Adaptation means to differential thermal dilatations}
- F02C 7/36: Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H)
- F16J 15/3448: {the pressing force resulting from fluid pressure}
- F16J 15/3452: {the pressing force resulting from the action of a spring}
- F16J 15/36: connected by a diaphragm {or bellow} to the other member
- F05D 2220/32: in gas turbines
- F05D 2230/60: Assembly methods
- F05D 2240/55: Seals
- F05D 2260/38: by a spring, i.e. spring loaded or biased towards a certain position
- F05D 2300/224: Carbon, e.g. graphite
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An exemplary carbon seal assembly generally may include a stator fixable to a static component, such as a mechanical housing of a gas turbine engine, and a rotor fixable to a rotating component, such as a shaft of the gas turbine engine, where the rotating component is rotatable relative to the static component. The carbon seal assembly may also include a carbon ring and a spring attached thereto positioned between the stator and the rotor, where the spring may be configured to move the carbon ring fore and aft between the stator and the rotor. The carbon seal assembly may further include a diaphragm operatively attached to stator and to the carbon ring and spring combination.

## Claims

### Claim 1

A carbon seal assembly comprising:
a stator fixable to a static component;
a rotor fixable to a rotating component rotatable relative to the static component;
a carbon ring disposed between the stator and the rotor;
a spring configured to move the carbon ring fore and aft between the stator and the rotor;
a diaphragm operatively attached to the stator and to a combination of the spring and the carbon ring;
a casing in which at least one of the spring and the carbon ring is at least partially disposed, wherein the diaphragm is attached to the casing; and
a limit stop extending from the stator toward the rotor, the limit stop being configured to engage with the casing to limit movement of the carbon ring in a direction towards the stator and to allow high pressure air between the diaphragm and the stator;
wherein the limit stop is unidirectional extending in a single direction and is positioned axially between the stator and the casing; and
wherein the spring is disposed in the casing in a direction facing the rotor, and the limit stop is disposed on an opposite side of the casing facing the stator.

### Claim 2 (depends on 1)

The carbon seal assembly of claim 1, wherein the static component is a mechanical housing and the rotating component is a shaft of a gas turbine engine.

### Claim 3 (depends on 1)

The carbon seal assembly of claim 1, wherein the carbon seal assembly is an air riding carbon seal.

### Claim 4 (depends on 1)

The carbon seal assembly of claim 1, wherein the carbon seal assembly is a contacting carbon face seal.

### Claim 5 (depends on 1)

The carbon seal assembly of claim 1, wherein the limit stop extends from an intermediate portion of the stator.

### Claim 6 (depends on 1)

The carbon seal assembly of claim 1, wherein the limit stop extends from a distal end of the stator.

### Claim 7 (depends on 1)

The carbon seal assembly of claim 1, wherein the limit stop has at least one vent hole for equalizing air pressure.

### Claim 8

A gas turbine engine, comprising:
a mechanical housing;
a shaft rotatable relative to the mechanical housing; and
a carbon seal assembly having:
a stator fixed to the mechanical housing;
a rotor fixed to the shaft;
a carbon ring disposed between the stator and the rotor;
a spring configured to move the carbon ring fore and aft between the stator and the rotor;
a casing in which at least one of the spring and the carbon ring is at least partially disposed;
a diaphragm attached to the casing; and
a limit stop extending from the stator toward the rotor, the limit stop being configured to engage with the casing to limit movement of the carbon ring in a direction towards the stator and to allow high pressure air between the diaphragm and the stator;
wherein the limit stop is unidirectional and is positioned axially between the stator and an axial end wall of the casing; and
wherein the spring is disposed in the casing in a direction facing the rotor, and the limit stop is disposed on an opposite side of the casing facing the stator.

### Claim 9 (depends on 8)

The gas turbine engine of claim 8, wherein the mechanical housing and the shaft are embodied in a gearbox.

### Claim 10 (depends on 8)

The gas turbine engine of claim 8, wherein the carbon seal assembly is an air riding carbon seal.

### Claim 11 (depends on 8)

The gas turbine engine of claim 8, wherein the carbon seal assembly is a contacting carbon face seal.

### Claim 12 (depends on 8)

The gas turbine engine of claim 8, wherein the limit stop extends from an intermediate portion of the stator.

### Claim 13 (depends on 8)

The gas turbine engine of claim 8, wherein the limit stop extends from a distal end of the stator.

### Claim 14 (depends on 8)

The gas turbine engine of claim 8, wherein the limit stop is porous.

### Claim 15

A method comprising:
attaching a diaphragm to a stator and a combination of a carbon ring and a spring to form a static assembly;
fixing a rotor to a rotating component rotatable relative to a static component;
fixing the static assembly to the static component; and
positioning a unidirectional limit stop axially between the stator and an axial end wall of a casing in which the carbon ring and the spring are at least partially disposed such that the limit stop is configured to engage with the casing to limit movement of the carbon ring in a direction towards the stator and to allow high pressure air between the diaphragm and the stator, the limit stop extending in a single direction;
wherein the combination of the carbon ring and the spring is positioned between the stator and the rotor such that the carbon ring is movable toward and away from the rotor; and
wherein the spring is disposed in the casing in a direction facing the rotor, and the limit stop is disposed on an opposite side of the casing facing the stator.

### Claim 16 (depends on 15)

The method of claim 15, wherein the static component is a mechanical housing and the rotating component is a shaft of a gas turbine engine.

### Claim 17 (depends on 15)

The method of claim 15, wherein the limit stop extends from an intermediate portion of the stator.

### Claim 18 (depends on 15)

The method of claim 15, wherein the limit stop extends from a distal end of the stator.

### Claim 19 (depends on 1)

The carbon seal assembly of claim 1, wherein the diaphragm has a bellows configuration.

### Claim 20 (depends on 1)

The carbon seal assembly of claim 1, wherein the diaphragm extends in a radial direction.