Spiral groove gas lubricated seal

• US 5,039,113 A
• Filed: 01/17/1990
• Issued: 08/13/1991
• Est. Priority Date: 01/17/1990
• Status: Expired due to Fees

• Current Assignee: EG&G Sealol Incorporated
• Original Assignee: EG&G Sealol Incorporated
• Inventors: Gardner, James F.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Cummings, Scott
• Application Number:
  US07/466,656
• Time in Patent Office: 573 Days
• Field of Search: 277/71, 277/81 R, 277/81 S, 277/81 P, 277/84, 277/85, 277/93, 277/93 SD, 277/96, 277/96.1
• US Class Current: 277/379
• CPC Class Codes: F16J 15/3412 with cavities F16J15/3424 takes precedence

Abstract

A dry running gas seal includes a stationary seal ring carrier attached to the machine body wherein the stationary seal ring carrier has an annular pocket, a stationary seal ring held in the pocket, a rotary seal ring carrier fixedly attached to the shaft wherein the rotary ring carrier has an annular pocket, a rotary seal ring held in the pocket wherein the rotary seal ring has a sealing face held adjacent to the stationary seal ring and grooves formed on the sealing face of the rotary seal ring wherein the grooves have an average angle of 5 to 15 degrees. The seal further comprises: an annular notch formed in a portion of the stationary seal ring axially away from the rotary seal ring, a "T" shaped insert extending into the notch, and an "O" ring disposed between the insert and the inner walls of the pocket in the stationary seal ring carrier. The seal further includes an annular groove formed in the radially inner wall of the rotary seal ring carrier, and a finger spring disposed in the groove.

Claims

1. A dry-running seal, for seal for sealing a gas in a machine body, the seal having a stationary seal ring assembly and a rotary seal ring assembly attachable to a rotatable shaft, wherein

said rotary seal ring assembly comprises:

A. a rotary seal ring including;

a sealing face at one end axial end of said rotary seal ring;

a back face at the other axial end;

at least one radially inner surface; and

a radially outer surface having at least one axial groove formed therein;

B. spiral grooves formed in said sealing face of said rotary seal ring said grooves extending from the outside diameter of said sealing face of said rotary seal ring radially inward across 50 to 65% of said sealing face, said grooves having an average angle ranging from 5 to 15 degrees;

C. a rotary seal ring carrier including;

i. an annular pocket formed in said rotary seal ring carrier for accepting said rotary seal ring, said pocket having a bottom, a radially inner, axially extending wall and a radially outer, axially extending wall;

ii. an annular "L" shaped spring clip including an axially parallel portion having at least one radially inward protruding dent formed therein, and an axially orthogonal portion, said axially parallel portion adapted for press fitting against said radially outer wall of said pocket in said rotary seal ring carrier, said axially orthogonal portion extending over an annular notch in the outside diameter of said sealing face, and said dent fitting into said groove formed in said rotary seal ring;

iii. an annular groove formed in said inner wall of said pocket formed in said rotary seal ring carrier; and

iv. a finger spring located in said annular groove; and

D. a shaft attachment comprising;

i. an extended annular portion of said rotary seal ring carrier, said extended annular surface adapted for fitting over said shaft, said extended annular portion having a radially inner surface adjacent to but spaced from said shaft for isolating said rotary seal ring carrier from heat in said shaft; and

ii. means for maintaining the fit of said rotary seal ring carrier to said shaft regardless of relative thermal and centrifugal expansion therebetween.

2. The seal as claimed in claim 1 further comprising:

means for cooling the rotary seal ring including at least one pathway passing through said bottom of said rotary ring carrier for providing a fluid communication of the gas to said pocket of said seal ring carrier, said pathway being slanted toward the direction of rotation, whereby gas is drawn into said pocket when the rotary seal ring is rotating; and

means for venting said gas from said pocket.

3. The seal as claimed in claim 2 further comprising sealing means positioned inwardly of said at least one pathway and between the back face of said rotary seal ring and the bottom of said pocket for preventing the flow of drawn gas beyond said sealing means.

4. The seal as claimed in claim 3 wherein said means for venting includes at least one hole formed in said seal ring carrier.

5. A rotary seal ring assembly for a dry-running gas seal, the assembly comprising:

I. a rotary seal ring; and

II. a rotary seal ring carrier including;

A. an annular pocket formed in said rotary seal ring carrier for accepting said rotary seal ring, said pocket having a bottom, a radially inner, axially extending wall and a radially outer, axially extending wall; and

B. an annular "L" shaped spring clip including an axially parallel portion having radially inward protruding dents formed therein, and an axially orthogonal portion, said axially parallel portion adapted for press fitting against said radially outer wall of said pocket in said rotary seal ring carrier, and said axially orthogonal portion adapted for extending over the outside diameter of said sealing face;

whereby said pocket and said "L" shaped spring clip combine to contain said rotary seal ring in the event of a catastrophic failure.

6. The rotary seal assembly of claim 5 further comprising an "O" ring located in the bottom of said pocket between said rotary seal ring and said rotary seal ring carrier and wherein said axially orthogonal portion of said "L" shaped spring clip serves to press said rotary seal ring against said "O" ring.

7. A rotary seal ring carrier for holding a rotary seal ring in a dry-running gas seal, the carrier comprising:

an annular body;

an annular pocket formed in said annular body for holding the rotary seal ring, said pocket having a bottom, a radially inner wall and a radially outer wall;

an annular groove formed in said radially inner wall of said pocket; and

a finger spring located in said annular groove, said finger spring having an annular center section and including axially projecting fingers extending therefrom;

whereby said finger spring serves to center the rotary seal ring regardless of relative thermal expansion between the rotary seal ring and said rotary seal ring carrier.

8. A shaft attachment system for attaching a rotary seal ring carrier to a shaft, the attachment system comprising:

an extended annular portion of the ring carrier, said portion extending along the shaft and adapted for fitting over the shaft, said extended annular portion having a radially inner surface adjacent to but spaced from the shaft;

means for maintaining the fit of said rotary seal ring carrier to said shaft regardless of the relative thermal and centrifugal expansion therebetween,

wherein said extended portion has a first axial end and a second axial end axially opposite said first end, said means for maintaining fit comprising a first annular finger spring pocket formed in said radially inner surface adjacent to said first end and a second annular finger spring formed in said radially inner surface adjacent to said second end, and annular finger springs located in said finger spring pockets for pressing against the shaft and the radially inner surface of said extended annular portion and holding them in place.

9. A gas seal for sealing a gas, the seal having a rotary seal ring and a rotary seal ring carrier, said seal ring and carrier rotatable in a plane of rotation about a shaft, said seal comprising:

an annular pocket formed in said rotary seal ring carrier for holding said rotary seal ring, said pocket having a bottom, a radially inner, axially extending wall and a radially outer, axially extending wall;

means for cooling the seal ring including at least one pathway passing through said bottom of said seal ring carrier and providing a fluid communication of the gas to the pocket of said seal ring carrier, said pathway being slanted toward the direction of rotation, whereby gas is drawn into said pocket when the rotary seal ring is rotating; and

means for venting the gas from said pocket.

10. The seal as claimed in claim 9 further comprising sealing means position inwardly of said at least one pathway and between the back face of said rotary seal ring and the bottom of said pocket for preventing the flow of drawn gas beyond said sealing means.

11. The seal as claimed in claim 10 wherein said means for venting includes at least one hole formed in said seal ring carrier.

12. The seal as claimed in claim 9 wherein said pathway is slanted at 30 to 45 degrees from the plane of rotation.