Sealing apparatus having sequentially engageble seals

• US 20040007821A1
• Filed: 12/20/2002
• Published: 01/15/2004
• Est. Priority Date: 04/13/2000
• Status: Active Grant

• Current Assignee: Ashbridge & Roseburgh, Inc.
• Original Assignee: Ashbridge & Roseburgh, Inc.
• Inventors: Ramsay, Thomas W.
• Granted Patent: US 6,979,002 B2
• Time in Patent Office: Days
• US Class Current: 277/353
• CPC Class Codes: F16J 15/008 with provision to put out of action at least one sealing; One sealing sealing only on standstill; Emergency or servicing sealings F16J15/164 takes precedence
• CPC Class Codes: Y10S 277/914 Backup seal for failure of primary seal

Abstract

Advantageous seal systems (1500) are provided that include a barrier member movable relative (1504) to a shaft (1550) to allow sequential engagement of resilent seal members (1506), e.g., lip seals, with the shaft. Movement of the barrier member (1504) may be effected manually or through introduction of pressurized fluid to effect piston-like movement. The disclosed seal assemblies may include an automatic leak detector and may utilize such leak detection to effectuate automatic movement of the barrier member. The barrier member may be moved relative to the shaft while the shalt is in movement, e.g., rotating or reciprocating, thereby permitting seal maintenance without interruption in operation. As seal members are sequentially brought into sealing engagement with the shaft, the previously engaged seal members contribute to the sealing performance of the seal assembly, although no longer effective to establish a stand-alone seal with the shaft.

Claims

1. A seal assembly for sealing a shaft within a housing, comprising:

a) a plurality of resilient seal members radially biased towards said shaft and mounted with respect to said housing, at least one of said resilient seal members disposed to assume a preloaded condition out of contact with said shaft and a loaded condition in sealing contact with said shaft;

b) a barrier member in axial alignment with said shaft and defining a clearance space interposed between said shaft and said at least one resilient seal member in its preloaded condition, said barrier member mounted for movement relative to said shaft;

wherein said at least one resilient seal member deploys from said preloaded condition to said loaded condition in response to movement of said barrier member relative to said shaft, and wherein said movement effects sealing engagement between said at least one resilient seal member and said shaft.

2. A seal assembly according to claim 1, wherein said shaft includes a concentric sleeve fixedly secured thereto.

3. A seal assembly according to claim 1, wherein said barrier member comprises a barrier sleeve concentrically mounted around said shaft.

4. A seal assembly according to claim 1, wherein said plurality of resilient seal members are lip seals.

5. A seal assembly according to claim 1, wherein said shaft is rotating.

6. A seal assembly according to claim 1, wherein said barrier member is mounted for axial movement relative to said shaft.

7. A seal assembly according to claim 6, wherein said plurality of resilient seal members includes first and second resilient seal members configured to assume preloaded and loaded conditions, and wherein said first and second resilient seal members are sequentially deployed from said preloaded condition to said loaded condition in response to axial movement of said barrier member relative to said shaft.

8. A seal assembly according to claim 7, wherein said sequential deployment of said first and second resilient seal members effects sequential sealing engagement between said first and second resilient seal members and said shaft.

9. A seal assembly according to claim 7, wherein said second resilient seal member is deployed into sealing engagement with said shaft in response to a failure of said first resilient sealing element to maintain sealing engagement with said shaft, and wherein said first resilient sealing element effects a partial seal relative to said shaft notwithstanding said failure to maintain sealing engagement with said shaft.

10. A seal assembly according to claim 7, further comprising a leak detector and leak control mechanism, said leak control mechanism adapted to automatically effect said sequential deployment in response to said leak detector sensing a leak relative to said plurality of resilient seal members.

11. A seal assembly according to claim 7, further comprising a fluid conduit position d at least in part between said first and second resilient seal members.

12. A seal assembly according to claim 11, wherein said fluid conduit is configured and dimensioned to supply a fluid selected from the group consisting of a flushing fluid, a cooling fluid, a lubricating fluid, a barrier fluid, and combinations thereof.

13. A seal assembly according to claim 7, further comprising a control mechanism for limiting the axial movement of said barrier member relative to said shaft.

14. A seal assembly according to claim 13, wherein said control mechanism defines at least one predetermined increment for axial movement of said barrier member.

15. A seal assembly according to claim 14, wherein said at least one predetermined increment corresponds to deployment of said at least one resilient member from said preloaded condition to said loaded condition.

16. A seal assembly according to claim 14, wherein said at least one predetermined increment is defined by a detent mechanism.

17. A seal assembly according to claim 7, further comprising at least one additional resilient seal member configured to be deployed from a preloaded condition to a loaded condition, and wherein said at least one additional seal member is deployed from said preloaded condition to said loaded condition in response to axial movement of said barrier member relative to said shaft in sequence with said first and second resilient seal members.

18. A seal assembly according to claim 1, further comprising a mechanism for effecting movement of said barrier member relative to said shaft.

19. A seal assembly according to claim 18, wherein said mechanism is selected from the group consisting of a motor, a fluid-driven piston, and combinations thereof.

20. A seal assembly according to claim 18, further comprising a control mechanism that defines at least one predetermined increment for axial movement of said barrier member relative to said shaft, and wherein said movement of said barrier member relative to said shaft by said mechanism is delimited by said control mechanism.

21. A seal assembly according to claim 1, wherein said barrier sleeve includes at least one score line along an axis thereof.

23. A combination according to claim 18, wherein said mechanical unit is selected from the group consisting of a pump, valve, regulator, motor, and compressor.

24. A combination according to claim 18, wherein said plurality of resilient seal members includes first and second resilient seal members disposed to assume preloaded and loaded conditions, and wherein said first and second resilient seal members sequentially deploy to seal said shaft by translating between said preloaded and loaded conditions in response to movement of said barrier member relative to said shaft.

25. A combination according to claim 18, wherein said barrier member is mounted for axial movement relative to said shaft.

22. In combination:

a) a mechanical unit including a movable shaft mounted at least in part within a stationary housing;

b) a seal assembly mounted within said stationary housing for sealing said shaft, said seal assembly comprising;

i) a plurality of resilient seal members mounted with respect to said stationary housing, at least one of said resilient seal members disposed to assume a preloaded condition out of contact with said shaft and a loaded condition in sealing contact with said shaft;

ii) a barrier member defining a barrier region in axial alignment with said shaft, said barrier region interposed between said shaft and said at least one resilient seal member, said barrier member mounted for movement relative to said shaft;

wherein said at least one resilient seal member translates deploys between said preloaded condition and said loaded condition in response to movement of said barrier member relative to said shaft, and wherein said movement effects sealing engagement between said at least one resilient seal member and said shaft.

26. In a seal assembly for sealing a shaft within a housing, said seal assembly including first and second resilient seal members mounted with respect to said housing, th improv ment comprising:

a barrier member defining a barrier region in axial alignment with said shaft and mounted for axial movement relative to said shaft, said barrier region interposed between said shaft and said first and second resilient seal members;

wherein said first and second resilient seal members sequentially sealingly engage said shaft in response to translation of said barrier memb r relative to said shaft.

27. A seal assembly according to claim 26, further comprising a motor for effecting the axial movement of said barrier member relative to said shaft.

28. A seal assembly according to claim 27, wherein said motor includes a control mechanism which defines at least one predetermined increment for axial movement of said barrier member.

29. A method for effecting a seal with a shaft mounted within a stationary housing, comprising:

a) providing a seal assembly that includes first and second resilient seal members mounted with respect to said stationary housing and a barrier member defining a barrier region in axial alignment with said shaft and mounted for axial movement relative to said shaft, said barrier region interposed between said shaft and at least said second resilient seal member; and

b) moving said barrier member axially relative to said shaft a distance sufficient to free said second resilient seal member from said interposition of said barrier member, said s cond resilient seal member resiliently moving into sealing engagement with said shaft in response to said barrier member movement.

30. A method according to claim 29, wherein said barrier member is interposed between said shaft and said first and second seal members, and further comprising:

c) moving said barrier member axially relative to said shaft a distance sufficient to sequentially free said first and second resilient seal members from said interposition of said barrier member, said first and second resilient seal members sequentially resiliently moving into sealing engagement with said shaft in response to said barrier member movement.

31. A method according to claim 29, wherein said barrier member is moved axially relative to said shaft by introducing a pressurized fluid to a chamber to effect piston-like movement of said barrier member.

32. A method according to claim 29, further comprising a leak detector and leak control mechanism, said leak control mechanism adapted to automatically effect said axial movement of said barrier member in response to said leak detector sensing a leak relative to said seal assembly.

33. A method according to claim 29, wherein said shaft is moving relative to said stationary housing, and wherein said movement of said barrier member relative to said shaft is effected without interrupting said shaft movement.