SIMPLIFICATION OF ENGINE CORE REMOVAL FOR MAINTENANCE OF GAS TURBINE ENGINE

• US 20030051483A1
• Filed: 09/20/2001
• Published: 03/20/2003
• Est. Priority Date: 09/20/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Napier, Larry Wayne
• Granted Patent: US 6,606,863 B2
• Time in Patent Office: Days
• US Class Current: 60/792
• CPC Class Codes: F01D 25/243 Flange connections; Bolting arrangements F01D25/265 takes precedence
• CPC Class Codes: F01D 5/066 Connecting means for joining rotor-discs or rotor-elements together, e.g. by a central bolt, by clamps
• CPC Class Codes: F02C 7/06 Arrangements of bearings bearings F16C; Lubricating of turbo machines F01D25/18; of machines or engines in general F01M
• CPC Class Codes: F05D 2230/70 Disassembly methods

Abstract

Apparatus for simplifying maintenance of gas turbine engines. Ordinarily, to remove a high-pressure compressor in a twin-spool engine, many components of must be removed, such as parts of a booster, in order to gain access to a mounting nut which is threaded onto a shaft supporting the high-pressure compressor. The removal is necessary because the nut must be extracted from the engine after disengagement from the shaft. Under the invention, this removal-of-components is largely eliminated, by providing a stowage location for the nut within the engine. The nut is removed, and then threaded onto a set of threads specifically provided for storage of the nut, and for nothing else.

Claims

1. Apparatus, comprising:

a) a gas turbine engine containing a shaft which bears a shaft thread;

b) a nut having a mating thread to the shaft thread; and

c) a second thread on the nut.

2. Apparatus according to claim 1, wherein the nut, when mated to the shaft thread and torqued to a predetermined value, locks the shaft in place for normal operation of the engine.

3. Apparatus according to claim 2, wherein the shaft supports a high-pressure compressor and a high-pressure turbine.

4. Apparatus according to claim 1, and further comprising a thread mounted on a component of the engine, other than the shaft, of the same pitch, pitch diameter, and type as the second thread.

5. Apparatus according to claim 1, and further comprising a thread mounted on a component of the engine, other than the shaft, to which the nut is mountable using the second thread.

6. Apparatus according to claim 1, wherein the second thread is incapable of withstanding any design load for which the shaft thread is designed.

7. A method of removing a core from a gas turbine engine, the core including a casing within which lies a shaft bearing a high-pressure compressor and a high pressure turbine, the method comprising:

a) removing a nut from the shaft;

b) threading the nut onto a thread which is axially displaced from the core during normal engine operation; and

c) withdrawing the core from the engine.

8. Method according to claim 7, wherein the nut is not used to apply axial force to the core, to assist withdrawal of the core.

9. A method, comprising:

a) transporting a core to a partly disassembled gas turbine engine, which contains a nut in a stowed position;

b) inserting the core into the engine; and

c) removing the nut from the stowed position and threading the nut onto a shaft in the core.

10. Method according to claim 9, wherein the nut is not used to apply insertion force to the core.

11. Method according to claim 9, wherein removal of the nut from the stowed position comprises de-threading the nut from a thread.

12. Apparatus, comprising:

a) a gas turbine engine which includes a core, which includes a casing within in which lies a shaft bearing a high-pressure compressor and a high pressure turbine;

b) an annular seal axially displaced from the core;

c) an internal thread on an inner surface of the annular seal;

d) an external thread on the shaft; and

e) a nut having inner threads and outer threads, such that

i) when the nut is torqued to a predetermined level on the thread of the shaft, the core is held in an operative position; and

ii) when the nut is stowed on the internal thread of the seal, the core is removable from the engine.

13. Method, comprising:

a) removing a coupling nut from a shaft of a gas turbine engine;

b) stowing the coupling nut on an annulus within the engine, such that internal threads of the coupling nut are fully exposed; and

c) performing at least one of the following;

inspecting, cleaning, and lubricating the coupling nut, while mounted on the annulus.

14. Method according to claim 13, wherein the coupling nut comprises internal threads which engage the shaft and external threads which contact the annulus.

15. Method according to claim 13, wherein the annulus comprises internal threads which engage the internal threads of the coupling nut.