Turbine blade maintenance method

Patent metadata

Field	Value
Publication number	US-11504750-B2
Application number	US-201615747530-A
Country	US
Kind code	B2
Filing date	Dec 13, 2016
Priority date	Dec 28, 2015
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

A cleaning process (blasted-particles cleaning process) includes performing, a plural number of consecutive cycles, an ultrasonic cleaning treatment including immersing a turbine rotor blade in a water basin and conducting an ultrasonic wave into the water basin to clean the turbine rotor blade, and a pressurized-water cleaning treatment including spraying pressurized water into an internal cooling flow channel after the ultrasonic cleaning treatment is performed. The cleaning process is performed after a bonding coat layer removing process of removing a bonding coat layer (first coating layer) by chemical treatment, and a cleaning process of cleaning the turbine blade by blast treatment. Heat tinging process is then performed.

First claim

The invention claimed is:

1. A turbine blade maintenance method, the turbine blade including a first coating layer as a protective layer applied to an external surface and internal cooling flow channels for circulating a refrigerant, the internal cooling flow channels being open at a blade tip and at a blade root of the turbine blade, the turbine blade maintenance method comprising:
performing a first coating layer removing process including removing the first coating layer by chemical treatment;
performing a cleaning process including a blast treatment for cleaning the turbine blade, the blast treatment being performed after the first coating layer removing process;
after performing the cleaning process, performing a blasted-particles cleaning process including performing the following treatments a plural number of consecutive cycles:
(i) an ultrasonic cleaning treatment including immersing the turbine blade in a water basin and conducting ultrasonic sound waves into the water basin to clean the turbine blade, and
(ii) pressurized-water cleaning treatment including spraying pressurized water into the internal cooling flow channels after performing the ultrasonic cleaning treatment; and

after performing the blasted-particles cleaning process, performing a heat tinting process including heat treatment testing to determine whether the first coating layer remains on the turbine blade
wherein the pressurized-water cleaning treatment comprises spraying pressurized water into the internal cooling flow channels through one of (A) openings of the internal cooling flow channels in the blade tip and (B) openings of the internal cooling flow channels in the blade root in a state in which the turbine blade is oriented so that a longitudinal axis of the turbine blade extends in the vertical direction with the one of the openings of the internal cooling flow channels being located on an upper end of the turbine blade with respect to the vertical direction, and
wherein, after completion of each cycle of the pressurized-water cleaning treatment while performing the blasted-particles cleaning process, an orientation of the turbine blade is switched to invert the upper end and a lower end of the turbine blade with respect to the vertical direction before conducting a subsequent cycle of the pressurized-water cleaning treatment.

2. The turbine blade maintenance method according to claim 1 , wherein, while performing the blasted-particles cleaning process, a first cycle of the pressurized-water cleaning treatment is performed in a state in which the turbine blade is oriented so that the blade tip is on the upper end in the vertical direction.

3. The turbine blade maintenance method according to claim 1 , further comprising:
performing a residual-stress removing process including performing heat treatment so as to remove residual stress in the turbine blade before performing the first coating layer removing process; and
before performing the residual stress removing process, performing a scale cleaning process including a scale-removal ultrasonic cleaning treatment and a scale-removal pressurized-water cleaning treatment performed after the scale-removal ultrasonic cleaning treatment.

4. The turbine blade maintenance method according to claim 3 , wherein
the turbine blade includes a second coating layer applied to an exterior of the first coating layer, and
the turbine blade maintenance method further comprises a second coating layer removing process for removing the second coating layer by blast treatment before the residual-stress removing process.

Assignees

• Mitsubishi Hitachi Power Sys Ltd
• Mitsubishi Heavy Ind Ltd

Inventors

• Takeuchi Yasushi
• Kawachi Yosuke
• Inoue Yoshiyuki

Classifications

• B24C3/327

  by an axially-moving flow of abrasive particles without passing a blast gun, impeller or the like along the internal surface (polishing or abrading surfaces using plastically deformable grinding compound, moved relatively to the workpiece under the influence of pressure B24B31/116) · CPC title

• B08B9/0321

  using pressurised, pulsating or purging fluid (E04F17/126 takes precedence) · CPC title

• B08B3/08 Primary

  the liquid having chemical or dissolving effect · CPC title

• F01D25/00

  Component parts, details, or accessories, not provided for in, or of interest apart from, other groups · CPC title

• F02C7/18

  the medium being gaseous, e.g. air {(F02C7/125 takes precedence)} · CPC title