# US 2013/0156587 A1 · Retrofitting methods and devices for large steam turbines

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- Number: US 2013/0156587 A1
- Document ID: US20130156587A1
- Status: Published application
- Kind: A1
- Application number: 13/631,882
- Filed: 2012-09-29
- Published: 2013-06-20
- Earliest claimed: 2011-09-30
- Assignees: ALSTOM Technology Ltd
- Inventors: Sigurd Kubel; Rolf Hunziker
- Web page: https://patentgrep.com/patent/US20130156587A1

## CPC

- F01D 5/005: {Repairing methods or devices}
- B23P 6/005: {using only replacement pieces of a particular form}
- F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments}
- F01D 5/3007: {of axial insertion type}
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- Y10T 29/49318: Repairing or disassembling
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of replacing rotating metal blades of a steam turbine inserted into a rotor having one or more existing grooves for inserting root sections of the metal blades is described, the method including the steps of providing replacement blades having radially inwards directed root sections of fiber-reinforced composite material, changing the shape of the one or more grooves in the rotor to form a cavity for the insertion of the root sections of fiber-reinforced composite material and inserting the replacement blades into the rotor.

## Claims

### Claim 1

A method of replacing rotating metal blades of a steam turbine inserted into a rotor having at least one existing groove configured to receive root sections of the metal blades, the method comprising:
providing replacement blades having radially inwards directed root sections of fiber-reinforced composite material;
changing a shape of the at least one groove in the rotor to provide cavities for the insertion of the root sections of fiber-reinforced composite material; and
inserting the replacement blades into the rotor.

### Claim 2 (depends on 1)

The method of claim 1 wherein the shape of the at least one existing groove is changed by machining an altered groove profile into the rotor and/or by inserting adapters into the existing grooves.

### Claim 3 (depends on 2)

The method of claim 2 wherein the at least one existing groove have several teeth or hooks and the shape of the at least one existing groove is changed by machining an altered groove profile into the rotor such that at least the top and the bottom teeth remain without significant alterations and the adapter is hooked onto the remaining at least the top and the bottom teeth.

### Claim 4 (depends on 1)

The method of claim 1 wherein the root sections of fiber-reinforced composite material extend into the altered groove profile in the rotor and/or the adapters such that the end sections are separated from steam in the turbine by at least one layer of metal.

### Claim 5 (depends on 2)

The method of claim 2 wherein a transition between fiber-reinforced composite material of the root section of the blades and the metal occurs within a body of the adapter.

### Claim 6 (depends on 2)

The method of claim 2 wherein the root sections of fiber-reinforced composite material either extend into the grooves or the adapters include a cavity extending radially outward beyond an outer diameter of the rotor into which cavity the end sections of fiber-reinforced composite material are inserted.

### Claim 7

An adapter for replacing rotating metal blades of a steam turbine inserted into a rotor having at least one existing groove configured to receive root sections of the metal blades with replacement blades having radially inwards directed root sections of fiber-reinforced composite material, the adapter comprising at least one section matching at least part of the at least one existing groove for fixing the adapter to the rotor and at least one cavity portion to accommodate the radially inwards directed root sections of fiber-reinforced composite material.

### Claim 8 (depends on 7)

An adapter of claim 7, wherein the at least one section matching at least part of the existing grooves for fixing the adapter matches bottom and top hooks or teeth as applied to fix the root sections of the metal blades to the rotor.