# US 9,752,587 B2 · Variable bleed slot in centrifugal impeller

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- Number: US 9,752,587 B2
- Document ID: US9752587B2
- Status: Granted
- Kind: B2
- Application number: 14/301,893
- Filed: 2014-06-11
- Published: 2014-12-18
- Granted: 2017-09-05
- Earliest claimed: 2013-06-17
- Assignees: United Technologies Corporation
- Applicants: United Technologies Corporation
- Inventors: Benjamin E. Fishler
- Web page: https://patentgrep.com/patent/US9752587B2

## CPC

- F04D 27/0215: {Arrangements therefor, e.g. bleed or by-pass valves}
- F01D 9/045: {for radial flow machines or engines}
- F01D 17/143: {the shiftable member being a wall, or part thereof of a radial diffuser}
- F02C 6/08: the gas being bled from the gas-turbine compressor
- F04D 27/023: {Details or means for fluid extraction}
- F04D 29/4206: {especially adapted for elastic fluid pumps}
- F04D 29/682: {by fluid extraction}
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- 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)

## Abstract

The present disclosure relates to shroud bleed in centrifugal compressors. An air-limiting component 130 may be located adjacent to a shroud 120. The shroud 120 may have a primary bleed slot 210, and the air-limiting component 130 may have a secondary bleed slot 310. The primary bleed slot 210 and the secondary bleed slot 310 may overlap at an effective bleed slot location. The air-limiting component 130 may rotate relative to the shroud 120, which may change a streamwise location of the effective bleed slot.

## Claims

### Claim 1

A centrifugal compressor comprising:
a shroud located adjacent to an impeller, the shroud comprising a plurality of primary bleed slots;
an air-limiting component located adjacent to the shroud, the air-limiting component comprising a plurality of secondary bleed slots overlapping the plurality of primary bleed slots, wherein the plurality of secondary bleed slots are offset by an angle from the plurality of primary bleed slots;
a plurality of bearings located between the shroud and the air-limiting component; and
an actuator configured to rotate the air-limiting component, wherein, in response to the actuator rotating the air-limiting component, an overlapping position of the plurality of primary bleed slots and the plurality of secondary bleed slots varies.

### Claim 2 (depends on 1)

The centrifugal compressor of claim 1, wherein the plurality of primary bleed slots and the plurality of secondary bleed slots share a common streamwise position overlap.

### Claim 3 (depends on 1)

The centrifugal compressor of claim 1, wherein the air-limiting component is configured to rotate relative to the shroud.

### Claim 4 (depends on 1)

The centrifugal compressor of claim 1, wherein a portion of a secondary bleed slot is capable of overlapping an entire primary bleed slot.

### Claim 5

A method comprising:
determining a shroud bleed location in a centrifugal compressor, wherein the determining comprises iteratively measuring an efficiency of the centrifugal compressor; and
rotating an air-limiting component relative to a shroud, such that a bleed slot in the air-limiting component overlaps a bleed slot in the shroud at the shroud bleed location.

### Claim 6 (depends on 5)

The method of claim 5, wherein the rotating changes a streamwise distance of where the bleed slots overlap.

### Claim 7 (depends on 5)

The method of claim 5, further comprising detecting an instability, and in response to the detecting, rotating the air-limiting component.

### Claim 8

A centrifugal compressor comprising:
a shroud located adjacent to an impeller, the shroud comprising a plurality of primary bleed slots;
an air-limiting component located adjacent to the shroud, the air-limiting component comprising a plurality of secondary bleed slots overlapping the plurality of primary bleed slots, wherein at least one of the plurality of primary bleed slots and the plurality of secondary bleed slots vary in width;
a plurality of bearings located between the shroud and the air-limiting component; and
an actuator configured to rotate the air-limiting component, wherein, in response to the actuator rotating the air-limiting component, an overlapping position of the plurality of primary bleed slots and the plurality of secondary bleed slots varies.

### Claim 9

A method comprising:
determining a shroud bleed location in a centrifugal compressor; and
rotating an air-limiting component relative to a shroud, such that a bleed slot in the air-limiting component overlaps a bleed slot in the shroud at the shroud bleed location, wherein the rotating changes a streamwise location of where the bleed slots overlap.