Turbomachinery seal

• US 6,808,179 B1
• Filed: 07/31/1998
• Issued: 10/26/2004
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Concepts NREC, LLC
• Original Assignee: Concepts ETI Incorporated (Concepts NREC, LLC)
• Inventors: Bhattacharyya, Abhijit, Marscher, William D.
• Primary Examiner(s): JOHNSON, STEPHEN
• Application Number:
  US09/127,372
• Time in Patent Office: 2,279 Days
• Field of Search: 415/174.2, 415/174.3, 415/174.5, 415/230, 415/231, 277/348-349, 277/350, 277/351, 277/355
• US Class Current: 277/348
• CPC Class Codes: F01D 11/00 Preventing or minimising internal leakage of working-fluid, e.g. between stages sealings in general F16J ; sealing arrangements for transition ducts of combustor cans F01D9/023
• CPC Class Codes: F05D 2240/56 Brush seals
• CPC Class Codes: F16J 15/3288 Filamentary structures, e.g. brush seals

Abstract

A turbomachinery seal (20) attached to annular member (30) which surrounds and rotatably engages a shaft (34). The seal is capable of sealing pressure differentials between a high pressure region (24) and a low pressure region (26) well in excess of 300 psi at relatively low leakage rates. One embodiment (120) of the seal includes a plurality of confronting plates (128) arranged so as to form an annular structure. Another embodiment (220) includes a plurality of bristle packs (252), each positioned between annular plates (256) having an axial taper (278) adjacent radially inner ends (274). In another embodiment (320) bristles 334′ and 334″ extend in axial positive and negative directions so as to create an interleaved bristle structure. In yet another embodiment (720), a plurality of elongate members (450) are embedded within bristles (434). A turbomachine (550) includes seals 520′ and 520″ of the invention.

Claims

1. A seal assembly designed for rise with a first member between a high pressure region and a low pressure region, the assembly comprising:

a. a support with a central axis; and

b. a sealing means for engaging the first member and, when said sealing means is engaged with the first member, maintaining a pressure difference of greater than 300 psi between the high pressure region and the low pressure region while permitting relative rotational movement between the first member and said sealing means, said sealing means being attached to said support so that a portion of said sealing means extends radially beyond said support, said portion defining an annular space, said sealing means limiting leakage between the high pressure region and the low pressure region when said sealing means is engaged with the first member such that fluid flow from the high pressure region to the low pressure region through said sealing means does not exceed thirty percent of what said fluid flow would be through said annular space if said portion of said sealing means did not occupy said annular space, said sealing means having a plurality of bristles and at least one second member that includes a tapered portion having a taper confronting said plurality of bristles and located proximate the first member when the seal assembly is engaged with the first member.

2. A seal assembly according to claim 1, wherein said sealing means is designed such that said fluid flow from the high pressure region to the low pressure region through said annular space does not exceed twenty percent of what said fluid flow would be through said annular space if said portion of said sealing means did not occupy said annular space.

3. A seal assembly according to claim 1, wherein said sealing means is designed such that said fluid flow from the high pressure region to the low pressure region through said annular space does not exceed ten percent of what said fluid flow would be through said annular space if said portion of said sealing means did not occupy said annular space.

4. A seal assembly according to claim 1, wherein said second member comprises an annular ring.

5. A seal assembly according to claim 1, further comprising a plurality of second members, wherein each second member comprises an elongate structure.

6. A seal assembly according to claim 5, wherein said plurality of bristles forms a bristle bed and said plurality of second members extend into said bristle bed.

8. A brush seal according to claim 1, wherein, when said brush seal is used with the first member, said plurality of bristles is sized to engage the first member with an interference fit during relative rotational movement between the first member and said plurality of bristles.

9. A brush seal according to claim 8, wherein, when said brush seal is used with the first member, at least some of said plurality of bristles are sized so as to have an interference with the first member of about 0.002″

to 0.007″

.

10. A brush seal according to claim 9, wherein said interference is about 0.0035″

.

11. A brush seal according to claim 8, wherein at least some of said plurality of bristles have a thickness ranging from 0.0015″

to 0.0035″

.

12. A brush seal according to claim 11, wherein said thickness is about 0.0025″

.

7. A brush seal intended for use with a first member, the seal comprising:

a. a support having a central axis;

b. a plurality of annular plates attached to said support so that each of said plates is spaced a first axial distance from adjacent plates, as measured along said central axis, so as to form a cavity between pairs of adjacent plates, wherein each of said plates has an axial thickness, a radially inner end and a radially outer end, with at least one of said plurality of plates having a taper adjacent said radially inner end in which said axial thickness decreases from (i) a first amount proximate, but spaced from, said radially inner end to (ii) a second, lesser, amount at said radially inner end; and

c. a plurality of bristles positioned in said cavity;

d. wherein said taper confronts said plurality of bristles.

13. A brush seal according to claim 7, wherein said plurality of bristles are positioned relative to said support so that said bristles form an angle θ

with respect to radii of said central axis, wherein θ

ranges from 30°

to 55°

.

14. A brush seal according to claim 13, wherein θ

is about 45°

.

15. A brush seal according to claim 7, wherein adjacent ones of said plurality of bristles have a gap there between of no more than about 0.0005″

.

16. A brush seal according to claim 7, wherein said plurality of bristles have a radial length, further wherein said annular plates have a radial length selected so that said annular plates block axial movement parallel to said central axis of a first portion of said radial length of said plurality of bristles and do not block axial movement of a second portion of said radial length of said plurality of bristles.

17. A brush seal according to claim 16, wherein the length ratio of said first portion to said radial length is at least 0.8.

18. A brush seal according to claim 7, wherein said taper is inclined with respect to radii of said central axis at an angle ranging from 2°

to 15°

.

19. A brush seal intended for use with a first member, the seal comprising:

a. a support having a central axis;

b. a plurality of bristles attached to said support so as to form an annular bristle bed surrounding said central axis; and

c. a plurality of elongate structures, each having a longitudinal axis, attached to said support so as to be positioned within said bristle bed such that each of said plurality of elongate structures is immediately laterally surrounded 360°

by said bristle bed, wherein said plurality of elongate structures are less flexible than said plurality of bristles.

20. A brush seal according to claim 19, wherein at least some of said plurality of elongate structures each have a circular cross-sectional configuration in a plane perpendicular to the corresponding said longitudinal axis.

21. A brush seal according to claim 20, wherein at least some of said plurality of elongate structures have a proximal end attached to said support and a distal end, further wherein said distal end has a tapered configuration.

22. A brush seal according to claim 19, wherein at least some of said elongate structures each have a non-circular cross-sectional configuration in a plane perpendicular to the corresponding said longitudinal axis.

23. A brush seal according to claim 19, wherein, when said brush seal is used with the first member, said plurality of bristles are sized to engage the first member with an interference fit ranging from 0.002″

to 0.007″

.

24. A brush seal according to claim 19, wherein said brush seal, when used with the first member and positioned between a high pressure region and a low pressure region, maintains a pressure differential between said regions of at least 300 psi during relative rotational movement between said bristles and the first member.

25. A brush seal according to claim 19, wherein said support has an inner circumference and said plurality of elongate structures are arranged so that ones of said plurality of elongate structures are spaced from one another along said inner circumference.

26. A brush seal according to claim 25, wherein said plurality of elongate structures are arranged in a plurality of groups such that at least some of said plurality of groups are spaced from one another along said inner circumference.

27. A turbomachine comprising:

a. a first region;

b. a first member supported for rotation about a central axis;

c. a housing having a second region in which said first member is received, said second region being sized and configured so that said first member can rotate relative to said housing within said second region; and

d. a sealing means for maintaining a pressure difference of greater than 300 psi between said first region and said second region while permitting relative rotational movement between said first member and said housing, said sealing means engaging said first member and said housing so that a portion of said sealing means extends radially beyond said housing, said portion defining an annular space, said sealing means limiting leakage between said first region and said second region such that fluid flow between said first region to said second region through said sealing means does not exceed thirty percent of what said fluid flow would be through said annular space if said portion of said sealing means did not occupy said annular space, said sealing means having a plurality of bristles and at least one second member that includes a tapered portion having a taper confronting said plurality of bristles and located proximate the first member when the seal assembly is used with the first member.

28. A turbomachine comprising:

a. a first region;

b. a first member supported for rotation about a central axis;

c. a housing having a second region in which said first member is received, said second region being sized and configured so that said first member can rotate relative to said housing within said second region; and

d. a seal, comprising;

i. a support attached to said housing;

ii. a plurality of annular plates attached to said support so that each of said plates is spaced a first axial distance from adjacent plates, as measured along said central axis, so as to form a cavity between adjacent plates, wherein each of said plates has an axial thickness, a radially inner end and a radially outer end, with at least one of said plurality of plates having a taper adjacent said radially inner end in which said axial thickness decreases from (i) a first amount proximate, but spaced from, said radially inner end to (ii) a second, lesser, amount at said radially inner end; and

iii. a plurality of bristles positioned in at least some of said cavities;

iv. wherein said taper confronts said plurality of bristles.

29. A turbomachine comprising:

a. a first region;

b. a first member supported for rotation about a central axis;

c. a housing having a second region in which said first member is received, said second region being sized and configured so that said first member can rotate relative to said housing within said second region; and

d. a seal, comprising;

i. a support attached to said housing;

ii. a plurality of bristles attached to said support so as to form an annular bristle bed surrounding said central axis; and

iii. a plurality of elongate structures attached to said support so as to be positioned within said bristle bed such that each of said plurality of elongate structures is immediately laterally surrounded 360°

by said bristle bed, wherein said plurality of elongate structures are less flexible than said plurality of bristles.

30. A turbomachine according to claim 29, wherein said support of said seal has an inner circumference and said plurality of elongate structures are arranged so that ones of said plurality of elongate structures are spaced from one another along said inner circumference.

31. A turbomachine according to claim 30, wherein said plurality of elongate structures are arranged in a plurality of groups such that at least some of said plurality of groups are spaced from one another along said inner circumference.