Balanced circumferential seal

1. A machine comprising:

an outer member;

an inner member mounted for rotation about an axis relative to the outer member; and

a seal system comprising:

a seal housing mounted to the outer member;

one or more seal rings held by the seal housing and having an inner diameter surface; and

a seal runner mounted to the inner member and having a first outer diameter surface portion contacting or facing the inner diameter surface of the one or more seal rings,

wherein:

the seal runner has;

a circumferential array of mounting features, each comprising one or more mounting holes;

a mounting section mounted to the inner member;

a sealing section including the first outer diameter surface portion radially outwardly spaced from the mounting section;

a first hub between the mounting section and the sealing section;

a balancing section including the one or more mounting holes of the mounting features of the circumferential array or mounting features; and

a second hub between the mounting section and the balancing section;

the first hub and the second hub are angled off-radial in the same direction from the mounting section to the sealing section and the balancing section, respectively; and

one or more weighs are mounted to one or more of the mounting features of the circumferential array of mounting features.

2. The machine of claim 1 wherein:

the one or more seal rings are two seal rings.

3. The machine of claim 1 wherein the sealing section axially overlaps the mounting section.

4. The machine of claim 1 wherein the mounting section has an inner diameter spline engaging a spline of the inner member.

5. The machine of claim 1 wherein the mounting section, the sealing section, the first hub, the balancing section, and the second hub are formed as a single metallic piece.

6. The machine of claim 5 wherein the single metallic piece is a Ti alloy.

7. The machine of claim 5 wherein the sealing section includes a chromium carbide coating.

8. The machine of claim 5 wherein the mounting section has an inner diameter spline engaging a spline of the inner member.

9. The machine of claim 8 wherein the spline of the inner member is a castellated rim.

10. The machine of claim 1 wherein the mounting section has an interference fit with the inner member.

11. The machine of claim 1 wherein:

each of the one or more weights is mounted via one or more fasteners extending through the one or more mounting holes.

12. The machine of claim 11 wherein:

the one or more seal rings are carbon seal rings.

13. The machine of claim 12 wherein:

the one or more seal rings are two seal rings.

14. The machine of claim 1 wherein:

the circumferential array of mounting features provides 12 to 60 discrete circumferential mounting locations.

15. The machine of claim 1 being a turbine engine wherein:

the inner member is a shaft and the outer member is a static structure.

16. The machine of claim 1 wherein:

the one or more mounting holes extend radially through the balancing section of the seal runner.

17. The machine of claim 1 wherein:

the one or more seal rings are carbon seal rings.

18. The machine of claim 1 wherein:

the balancing section extends axially to an end.

19. A method for manufacturing the machine of claim 1 , the method comprising:

mounting the seal runner to the inner member; and

after the mounting of the seal runner, mounting said one or more weights to said one or more of the mounting features, the mounting of the weights comprising inserting at least one fastener through each of the weights.

20. A method for manufacturing or using the machine of claim 1 , the method comprising:

rotating the inner member about the axis;

measuring vibrational parameters of the rotating inner member; and

mounting said one or more weights to improve the balance of the inner member, the mounting of the weights comprises inserting at least one fastener through each of the weights.