Damper and seal pin arrangement for a turbine blade

1. A bucket pair in a turbomachine comprising:

a first bucket having a first airfoil portion and a first shank portion, wherein the first shank portion has an outer planar surface;

an adjacent bucket having a second airfoil portion and a second shank portion adjacent said first shank portion, wherein the second shank portion has an outer planar surface;

a substantially axially-oriented groove in said outer planar surface of the first shank portion;

at least one substantially radially-oriented groove in said outer planar surface of the second shank portion and the substantially radially-oriented groove having a radially outer end overlapping the substantially axially-oriented groove of the first shank portion;

an elongated damper pin seated in said substantially axially-oriented groove in said first shank portion, wherein said elongated damper pin abuts the outer planar surface of the second shank portion; and

an elongated radial seal pin seated in said at least one substantially radially-oriented groove in said second shank portion, wherein the at least one elongated radial seal pin abuts the outer planar surface of the first shank portion, wherein said elongated radial seal pin abuts the outer planar surface of the first shank portion.

2. The bucket pair of claim 1 wherein said elongated damper pin includes at least a section round in cross-section.

3. The bucket pair of claim 2 wherein said at least one radial seal pin is includes a section round in cross-section.

4. The bucket pair of claim 3 wherein said at least one radial seal pin is located at a forward end of said second shank portion.

5. The bucket pair of claim 3 wherein said at least one radial seal pin overlaps a portion of the substantially axially-oriented groove.

6. The bucket pair of claim 5 wherein said elongated damper pin is engageable, in use, with angled wedge surfaces on each of said first and second shank portions.

7. The bucket pair of claim 1 wherein said elongated damper pin includes a middle portion which is uniformly round in cross-section and end portions each having cross-sections smaller in area than the cross-section of the middle portion.

8. The bucket pair of claim 7 wherein said cross-sections of the opposite ends are substantially semi-circular.

9. The bucket pair of claim 1 wherein said elongated damper pin is engageable, in use, with angled wedge surfaces on each of said first and second shank portions.

10. The bucket pair of claim 2 wherein said elongated damper pin is engageable, in use, with an angled wedge surface on said first shank portion and said section of the damper pin is engageable the planar outer surface on said second shank portion.

11. A bucket for a turbomachine rotor wheel comprising:

an airfoil portion, a shank portion and a dovetail mounting portion,

said shank portion including opposite sides each having an outer planar surface, the outer planar surface of one of said sides including a substantially axially-oriented groove extending between forward and aft ends of said shank portion, and the outer planar surface of the other of said sides including a least one substantially radially-oriented groove,

said substantially axially-oriented groove is adapted to receive an elongated damper pin, wherein said axially-oriented groove faces an outer planar surface of a shank portion of an adjacent bucket, and

said at least one substantially radially-oriented groove is adapted to receive an elongated radial seal pin, to face an outer planar surface of a shank portion of an adjacent bucket, and overlap a substantially axially-oriented groove in the shank portion of the adjacent bucket, wherein said at least one substantially radially-oriented groove faces the outer planar surface of the one of said sides of said shank portion.

12. The bucket of claim 11 wherein said substantially axially-oriented groove includes raised supporting surfaces at opposite ends of said substantially axially-oriented groove.

13. The bucket of claim 11 wherein said at least one substantially radially-oriented groove comprises first and second substantially radially-oriented grooves at forward and aft ends of said shank portion, adapted to receive first and second radial seal pins.

14. The bucket of claim 11 wherein said substantially radially-oriented groove is located at said forward end of said shank portion.

15. The bucket of claim 11 wherein said substantially axially-oriented groove includes a flat support surface and an angled wedge surface.

16. A bucket and pin assembly for a turbine machine rotor wheel comprising:

a bucket formed with an airfoil portion, a shank portion and a dovetail mounting portion, said shank portion including a first outer planar surface adapted to face a shank portion of an adjacent bucket and a second outer planar surface adapted to face a respective shank portion of another adjacent bucket, wherein the second and first outer planar surfaces are on opposite sides of the shank portion;

the first outer planar surface includes a substantially axially-oriented groove extending between forward and aft ends of said shank portion, and the second outer planar surface includes at least one substantially radially-oriented groove at a forward end of the bucket, wherein the first outer planar surface remains planar at locations aligned in a radial direction with the substantially radially-oriented groove and wherein the substantially radially-oriented groove extends radially to a location aligned in the radial direction with the substantially axially-oriented groove;

an elongated damper pin, wherein said elongated damper pin abuts an outer planar surface of a shank portion of the adjacent bucket, seated in said substantially axially-oriented groove, and

a radial seal pin, wherein said radial seal pin abuts an outer planar surface of a shank portion of another adjacent bucket, located in said at least one substantially radially-oriented groove.

17. The bucket and pin assembly of claim 16 wherein said substantially axially-oriented groove includes raised supporting surfaces at opposite ends of said substantially axially-oriented groove.

18. The bucket and pin assembly of claim 16 wherein said shank portion is formed with a substantially flat surface radially inward of said substantially axially-oriented groove.

19. The bucket and pin assembly of claim 16 wherein said substantially axially-oriented groove includes a flat support surface and an angled wedge surface.