Flat Bottom Damper Pin For Turbine Blades

• US 20140079529A1
• Filed: 09/14/2012
• Published: 03/20/2014
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Kareff, Spencer Aaron, Piersall, Matthew Robert
• Granted Patent: US 9,309,782 B2
• Time in Patent Office: Days
• US Class Current: 415/1
• CPC Class Codes: F01D 25/06 for preventing blade vibration means on blade-carrying members or blades F01D5/00
• CPC Class Codes: F01D 5/22 Blade-to-blade connections, e.g. for damping vibrations
• CPC Class Codes: F01D 5/24 using wire or the like

Abstract

A damper system for the buckets of a gas turbine engine. The damper system may include damper pins having a generally rounded top portion and a generally flat bottom portion along substantially the entire length thereof. The generally flat bottom portion may allow addition or removal of material to or from the pin in order to achieve an optimal dynamic weight ratio.

Claims

1. A damper pin for a bucket damper slot in at least one of two adjoining buckets installed in a rotor in a turbine, the damper pin comprising:

a. a generally rounded top portion, the rounded top portion configured to contact said adjoining buckets prior to full-speed rotation of said rotor; and

b. a generally flat bottom portion.

2. The damper pin of claim 1, wherein the damper pin is substantially symmetrical in cross section.

3. The damper pin of claim 1, wherein the damper pin includes bossed ends.

4. The damper pin of claim 1, wherein the generally flat bottom portion extends across substantially the entire length of the damper pin.

5. The damper pin of claim 1, wherein the generally rounded top portion comprises a fully round portion.

6. The damper pin of claim 1, wherein the damper pin includes a Murphy proofing tab on the bottom thereof

7. The damper pin of claim 1, wherein said generally rounded top portion and said generally flat bottom portion are joined at a pair of rounded or beveled edges.

8. A turbine engine comprising:

a. a rotor having a generally circular periphery;

b. a plurality of buckets mounted about the periphery of the rotor, each of said buckets including an airfoil extending outward from a platform; and

c. a damper for damping vibrations of said plurality of buckets, the damper including an elongate body, the elongate body being sized and shaped for receipt within a bucket damper slot formed in undercuts of said plurality of buckets so that the elongate body frictionally engages said undercuts to dampen vibrations of said buckets, said damper being generally symmetrical in cross section and comprising a generally rounded top portion, said generally rounded top portion configured to contact adjoining buckets prior to full-speed rotation of said rotor, said damper further comprising a generally flat bottom portion.

9. The turbine engine of claim 8, wherein the damper pin includes bossed ends.

10. The turbine engine of claim 8, wherein the generally flat bottom portion extends across substantially the entire length of the damper pin.

11. The turbine engine of claim 8, wherein the generally rounded top portion comprises a fully round portion.

12. The turbine engine of claim 8, wherein the damper pin includes a Murphy proofing tab on the generally flat bottom thereof

13. The turbine engine of claim 8, wherein said generally rounded top portion and said generally flat bottom portion are joined at a pair of rounded or beveled edges.

14. A method of fabricating a damper pin for a bucket of a gas turbine, comprising the steps of:

a. providing a pin having a generally rounded top portion;

b. determining an optimal dynamic weight ratio for said pin in said bucket;

c. adding material to, or removing a portion of material from, said pin to create a generally flat bottom portion along substantially the entire length of said pin, the weight of said damping pin following addition or removal of said material corresponding to said dynamic weight ratio for said bucket.

15. The method of claim 14 further comprising the steps of

a. installing said damper pin in a bucket damper slot of a gas turbine,

b. performing an engine test on said gas turbine;

c. determining from said engine test if said damper pin is performing at said optimal dynamic weight ratio; and

d. if said damper pin is not performing at said optimal dynamic weight ratio, adding or removing material to or from said flat bottom portion along substantially the entire length thereof, maintaining a substantially flat surface along substantially the entire length of said pin.

16. The method of claim 14 further comprising providing a Murphy proofing tab on said generally flat bottom portion.

17. The method of claim 14 further comprising providing bosses on said pin.

18. The method of claim 14 further comprising changing land lengths of said damper pin if said damper pin is not performing at said optimal dynamic weight ratio.