Repair method for a gas turbine

• US 6,546,627 B1
• Filed: 04/04/2001
• Issued: 04/15/2003
• Est. Priority Date: 09/14/2000
• Status: Expired due to Term

• Current Assignee: mitsubishi hitachi power systems, ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Sakurai, Shigeo, Sekihara, Masaru
• Primary Examiner(s): KOCZO JR, MICHAEL
• Application Number:
  US09/824,641
• Time in Patent Office: 741 Days
• Field of Search: 294/020.3, 294/020.8, 298/88, 298/891, 298/892.2, 607/52, 607/54, 415/117, 415/208.1
• US Class Current: 29/889.1
• CPC Class Codes: B23P 6/005 using only replacement pieces of a particular form
• CPC Class Codes: F01D 9/023 Transition ducts between combustor cans and first stage of the turbine in gas-turbine engines; their cooling or sealings
• CPC Class Codes: F05D 2250/231 cylindrical
• CPC Class Codes: F23R 3/00 Continuous combustion chambers using liquid or gaseous fuel
• CPC Class Codes: F23R 3/06 Arrangement of apertures along the flame tube
• CPC Class Codes: Y10T 29/49318 Repairing or disassembling
• CPC Class Codes: Y10T 29/49323 Assembling fluid flow directing devices, e.g., stators, diaphragms, nozzles
• CPC Class Codes: Y10T 29/4973 Replacing of defective part

Abstract

A gas turbine has a compressor for compressing air as a working fluid, a combustor for producing combustion gas by mixing fuel with the compressed air, and a turbine for generating a rotating force at the time of expansion of combustion gas. The gas turbine further includes a cylindrical liner; a transition piece for transferring the working fluid from the liner to the turbine; an outlet portion of the transition piece, which has a region parallel with a direction of a rotating shaft of the turbine; cooling holes formed in the region so that longitudinal intervals thereof are lengthened; and a picture frame portion provided to secure stiffness at an outlet of the outlet portion.

Claims

1. A repair method for a gas turbine having a compressor for compressing air as a working fluid, a combustor for producing combustion gas by mixing fuel with the compressed air, and a turbine for generating rotational power at the time of expansion of the combustion gas, said method comprising:

providing, on an outlet portion of a transition piece for transferring said working fluid to said turbine, a region parallel with the direction of rotating shaft of said turbine, cooling holes in said region so that the longitudinal intervals thereof are lengthened, and a picture frame portion to secure stiffness of an outlet of said outlet portion, and

cutting said outlet portion at a portion where the longitudinal intervals of said cooling holes are lengthened to separate said picture frame portion from said transition piece, and

welding another picture frame portion prepared in advance to the cut portion for replacement.

2. The repair method for a gas turbine according to claim 1, wherein said picture frame portion prepared in advance is another picture frame portion that has been cut from another transition piece and has been repaired for reuse.

3. The repair method for a gas turbine according to claim 1, wherein by grinding an end face of said cut-off picture frame portion, length of the whole of said transition piece is adjusted.

4. The repair method for a gas turbine according to claim 1, wherein said picture frame portion is welded to the cut portion via a connecting member.