# US 11,306,603 B2 · Steam turbine

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- Number: US 11,306,603 B2
- Document ID: US11306603B2
- Status: Granted
- Kind: B2
- Application number: 17/097,187
- Filed: 2020-11-13
- Published: 2021-05-20
- Granted: 2022-04-19
- Earliest claimed: 2019-11-19
- Assignees: Mitsubishi Heavy Industries, Ltd.
- Applicants: Mitsubishi Heavy Industries, Ltd.
- Inventors: Makoto Iwasaki; Rimpei Kawashita; Katsuya Yamashita
- Web page: https://patentgrep.com/patent/US11306603B2

## CPC

- F01D 11/00: Preventing or minimising internal leakage of working-fluid, e.g. between stages (sealings in general F16J {; sealing arrangements for transition ducts of combustor cans F01D9/023})
- F01D 11/02: by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08)
- F01D 5/12: Blades ({specially adapted for radial flow machines or engines F01D5/04}; blade roots F01D5/30; rotors with blades adjustable in operation F01D7/00; stator blades F01D9/02)
- F01D 11/005: {Sealing means between non relatively rotating elements}
- F01D 25/00: Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D 25/24: Casings (modified for heating or cooling F01D25/14); Casing parts, e.g. diaphragms, casing fastenings (casings for rotary machines or engines in general F16M {; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045})
- F05D 2220/31: in steam turbines
- F05D 2240/55: Seals
- F05D 2240/60: Shafts
- 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

A steam turbine includes a rotary shaft configured to rotate about an axis, a rotor blade including a rotor blade body extending radially outward from the rotary shaft, and a shroud on an end outside in a radial direction, a casing enclosing the rotor blade from outside in the radial direction and including a cavity accommodating the shroud on an inner circumference of the casing, a plurality of seal fins protruding radially inward from an opposing surface that faces the shroud in the cavity such that a clearance is between an outer circumferential surface of the shroud and the plurality of seal fins, and a plurality of swirl breaks upstream of the plurality of seal fins located furthest upstream in a direction of the axis in the cavity, the plurality of swirl breaks being arranged at intervals in a circumferential direction.

## Claims

### Claim 1

A steam turbine comprising:
a rotary shaft configured to rotate about an axis;
a rotor blade including a rotor blade body extending radially outward from the rotary shaft, and a shroud on an end outside in a radial direction;
a casing enclosing the rotor blade from outside in the radial direction and including a cavity accommodating the shroud on an inner circumference of the casing;
a plurality of seal fins protruding radially inward from an opposing surface that faces the shroud in the cavity such that a clearance is between an outer circumferential surface of the shroud and the plurality of plurality of seal fins;
a plurality of swirl breaks upstream of the plurality of seal fins located furthest upstream in a direction of the axis in the cavity, the plurality of swirl breaks being arranged at intervals in a circumferential direction; and
a protrusion on an edge of each of the plurality of swirl breaks, the protrusion protruding outward from each of the plurality of swirl breaks and having a triangular shape.

### Claim 2 (depends on 1)

The steam turbine according to claim 1, wherein the protrusion is one of a plurality of protrusions on the edge of each of the plurality of swirl breaks extending in a direction of the axis and on the edge of each of the plurality of swirl breaks extending in the radial direction with respect to the axis.