Backup seals in rotary pumps

• US 8,690,534 B1
• Filed: 06/08/2009
• Issued: 04/08/2014
• Est. Priority Date: 06/08/2009
• Status: Active Grant

• Current Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Original Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Inventors: Janocko, David Jeffrey, Bice, Charles David
• Primary Examiner(s): Wiehe, Nathaniel
• Assistant Examiner(s): HTAY, AYE SU MON
• Application Number:
  US12/480,554
• Time in Patent Office: 1,765 Days
• Field of Search: 415/231, 415/230, 277/508, 277/589, 277/531, 277/532, 277/467, 277/470, 277496-499
• US Class Current: 415/231
• CPC Class Codes: F04D 29/122 especially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/146 especially adapted for liquid pumps
• CPC Class Codes: F16J 15/164 the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid
• CPC Class Codes: F16J 15/18 with stuffing-boxes for elastic or plastic packings
• CPC Class Codes: F16J 15/445 with means for adjusting the clearance
• CPC Class Codes: F16J 15/46 with packing ring expanded or pressed into place by fluid pressure, e.g. inflatable packings connection of valves to inflatable elastic bodies B60C29/00; for sealing arrangements in vehicles B60J10/244; for sealing arrangements of openings in buildings E06B7/2318; for tube connections F16L

Abstract

Arrangements for promoting the restriction of fluid flow along a shaft via providing a deformable ring member in an annulus between the shaft and housing. In an initial general condition, the deformable ring member permits free fluid flow in a general direction along the shaft while in a second, constricted condition, the deformable ring closes or blocks a gap or clearance normally conducive to free fluid flow to thereby restrict fluid flow. An actuation medium, which can take any of a very wide variety of forms, preferably promotes constriction of the deformable ring member directly or indirectly.

Claims

1. In a structure comprising a shaft member and a support structure through which the shaft member extends, an arrangement for restricting fluid flow along the shaft member relative to the support structure in at least one annular space defined between the shaft member and the support structure, said arrangement for restricting fluid flow comprising:

a continuous ring member disposed about the shaft member, wherein said continuous ring member unbrokenly circumscribes the shaft member;

said continuous ring member being deformable in at least a radial direction towards and away from the shaft member, with respect to a central longitudinal axis of the shaft member;

an actuation medium for deforming said continuous ring member in the radial direction;

said actuation medium acting to deform said continuous ring member between a first general condition and a second general condition, wherein said actuation medium comprises a discontinuous ring element which is discontinuous with respect to a circumferential dimension of said discontinuous ring element, wherein said discontinuous ring element is disposed upstream of said continuous ring member;

wherein, in said first general condition, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the support structure, than in said second general condition, wherein in said second condition said continuous ring member constricts about the shaft member;

wherein the discontinuous ring element has two ends, and wherein in a first position, the ends are spaced apart, and wherein in a second position the ends are closer together;

wherein said discontinuous ring element effects an initial seal, the initial seal restricting fluid flow along the shaft member relative to the support structure at a location upstream from said continuous ring member;

wherein said discontinuous ring element actuates the deforming of the continuous ring member by promoting a pressure differential subsequent to effect an initial seal, the pressure differential acting to deform said continuous ring member between said first condition and said second condition;

wherein the fluid flow restricting arrangement further comprises a spacer element adapted to hold the ends of the discontinuous ring element apart in the first position and to permit the ends of the discontinuous ring element to close in the second position.

2. The fluid flow restricting arrangement according to claim 1, wherein said continuous ring member comprises a material with a lower modulus of elasticity than moduli of elasticity of the support structure and the shaft member.

3. The fluid flow restricting arrangement according to claim 2, wherein said material with a lower modulus of elasticity comprises a polymeric material.

4. The fluid flow restricting arrangement according to claim 3, wherein said polymeric material comprises PEEK.

5. The fluid flow restricting arrangement according to claim 1, further comprising:

an annular chamber which houses said continuous ring member; and

a retaining member forming at least a portion of a wall of the annular chamber.

6. The fluid flow restricting arrangement according to claim 1, further comprising:

an elastic member for providing downstream axial forces on said continuous ring member.

7. The fluid flow restricting arrangement according to claim 6,

wherein said elastic member is at least one spring.

8. The fluid flow restricting arrangement according to claim 1, wherein the spacer element is disposed between the ends of the discontinuous ring element in the first position and not disposed between the ends of the discontinuous ring element in the second position.

9. The fluid flow restricting arrangement according to claim 8, wherein the spacer element is a mechanical retractable plunger, and wherein retraction of the plunger permits the ends of the discontinuous ring element to close in the second position.

10. The fluid flow restricting arrangement according to claim 8, wherein the spacer element comprises a meltable or dissolvable material, and wherein melting or dissolving of the material permits the ends of the discontinuous ring element to close in the second position.

11. A rotary pump comprising:

a motor;

a shaft member extending from said motor;

an impeller attached to a free end of said shaft member;

a housing which encloses a major portion of said shaft member;

said housing comprising a seal housing which circumscribes at least a portion of said shaft member, said seal housing including at least one sealing element for restricting fluid flow along said shaft member;

said motor being configured for rotating said shaft member in a manner to drive said impeller; and

an arrangement for restricting fluid flow along the shaft member relative to the seal housing in at least one annular space defined between said shaft member and said seal housing;

said fluid flow restricting arrangement comprising a continuous ring member disposed about the shaft member, wherein said continuous ring member unbrokenly circumscribes the shaft member;

said continuous ring member being deformable in at least a radial direction towards and away from the shaft member, with respect to a central longitudinal axis of the shaft member;

an actuation medium for deforming said continuous ring member in the radial direction;

said actuation medium acting to deform said continuous ring member between a first condition and a second condition, wherein said actuation medium comprises a discontinuous ring element which is discontinuous with respect to a circumferential dimension of said discontinuous ring element, wherein said discontinuous ring element is disposed upstream of said continuous ring member;

wherein, in said first condition, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the seal housing, than in said second condition, wherein in said second condition said continuous ring member constricts about the shaft member;

wherein the discontinuous ring element has two ends, and wherein in a first position, the ends are spaced apart, and wherein in a second position the ends are closer together;

wherein said discontinuous ring element effects an initial seal, the initial seal restricting fluid flow along the shaft member relative to the housing at a location upstream from said continuous ring member;

wherein said discontinuous ring element actuates the deforming of the continuous ring member by promoting a pressure differential subsequent to effect an initial seal, the pressure differential acting to deform said continuous ring member between said first condition and said second condition

wherein the fluid flow restricting arrangement further comprises a spacer element adapted to hold the ends of the discontinuous ring element apart in the first position and to permit the ends of the discontinuous ring element to close in the second position.

12. The rotary pump according to claim 11, wherein said continuous ring member comprises a material with a lower modulus of elasticity than moduli of elasticity of the housing and the shaft member.

13. The rotary pump according to claim 11, wherein said rotary pump comprises a chemical processing pump.

14. The rotary pump according to claim 11, wherein said rotary pump comprises a reactor coolant pump.

15. In a structure comprising a shaft member and a support structure through which the shaft member extends, an arrangement for restricting fluid flow along the shaft member relative to the support structure in at least one annular space defined between the shaft member and the support structure, said arrangement for restricting fluid flow comprising:

a continuous ring member disposed about the shaft member, wherein said continuous ring member unbrokenly circumscribes the shaft member;

said continuous ring member being deformable in at least a radial direction towards and away from the shaft member, with respect to a central longitudinal axis of the shaft member;

an actuation medium for deforming said continuous ring member;

said actuation medium acting to deform said continuous ring member between a first condition and a second condition;

an anti-extrusion member recessed into a downstream face at an inner diameter portion of the continuous ring member for preventing any material from the continuous ring member from extruding in a downstream direction;

wherein, in said first condition, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the support structure, than in said second condition.