FIRE RESISTANT SEALING RING COMBINATION

• US 3,869,132 A
• Filed: 07/18/1973
• Issued: 03/04/1975
• Est. Priority Date: 07/18/1973
• Status: Expired due to Term

• Current Assignee: EG&G Pressure Science, Inc.
• Original Assignee: Bernard J. Sadoff Jr, Dudley D. Taylor, Horace P. Halling
• Inventors: Taylor, Dudley D., Sadoff, Bernard J. Jr., Halling, Horace P.
• Primary Examiner(s): Rothberg, Samuel B.
• Application Number:
  US05/380,200
• Time in Patent Office: 594 Days
• Field of Search: 277/26,180,205,206
• US Class Current: 277/608
• CPC Class Codes: F16J 15/002 comprising at least two sealings in succession F16J15/162, F16J15/40 take precedence
• CPC Class Codes: F16J 15/065 fire resistant
• CPC Class Codes: F16J 15/12 with metal reinforcement or covering
• CPC Class Codes: F16L 23/18 the sealing means being rings
• CPC Class Codes: Y10S 277/931 Seal including temperature responsive feature
• CPC Class Codes: Y10S 277/933 Chemical reaction or physical change of state
• CPC Class Codes: Y10S 277/944 Elastomer or plastic

Abstract

There is disclosed a fail-safe fire resistant sealing ring combination which provides a tight seal in a joint, such as in a fuel line. The primary sealing means for providing a tight seal under normal conditions is achieved by the use of an elastomeric sealing ring. A backup metallic sealing ring having radial leg portions which at least partially surround the elastomeric sealing ring is also provided. Another metallic confining means, e.g., a metallic ring which may be separate from or integral with one of the flanges forming the cavity in which the sealing rings are located, is situated contiguous to the sealing portion of the elastomeric sealing ring on the side opposite of the metallic sealing ring, i.e., in contact with the fluid which is being confined. Under conditions of extremely high temperatures such as generated by fire, the elastomeric seal will initially expand providing a driving force for the metallic sealing ring causing it to be driven with greater force into zero leakage sealing engagement with the sides of the line which is being sealed. When the elastomeric seal subsequently disintegrates due to the high temperature, the metallic seal provides a no-leak fuel seal. In the event of a fire, when fuel is flowing through the pipe, the inner metallic confining means prevents the disintegrating elastomeric compound from entering the fuel stream. It also prevents erosion of the elastomeric seal by the fuel flow during normal operation of the system.

Claims

1. The combination of a pair of relatively movable flange members which define between them a cavity in which high pressures and temperatures may be encountered, a primary elastomeric sealing ring positioned in said cavity which provides a tight seal under normal operating conditions, a secondary deflectable metallic sealing ring situated in said cavity at a point remote from contact with the confined fluid which is under pressure, said metallic sealing ring having curved leg portions which at least partially surround a portion of said elastomeric sealing ring, and a metallic ring situated in said cavity contiguous to said elastomeric ring on the side opposite of said metallic sealing ring defining means for confining the fluid and the elastomeric ring, whereby said last mentioned metallic ring prevents substantial expansion of said elastomeric ring in the direction of the fluid being confined so that when said elastomeric sealing ring expands under conditions of high temperature, it expands in the direction of said metallic sealing ring and forces said metallic sealing ring into a tighter sealing engagement with said cavity.

2. The combination as defined in claim 1 wherein said last mentioned metal ring prevents the fluid which is being confined from coming into substantial contact with said elastomeric sealing ring.

3. The combination of claim 1 wherein said elastomeric sealing ring comprises a sealing portion having a thickness which before being compRessed is slightly greater than the width of said cavity in which it is situated and a narrower portion positioned between the leg portions of said metallic sealing ring.

4. The combination as defined in claim 3 wherein said last mentioned metallic ring is bonded to the wider portion of said elastomeric sealing ring.

5. The combination as defined in claim 3 wherein said metallic sealing ring has a C-shaped radial cross-section.

6. The combination as defined in claim 3 wherein said metallic sealing ring has an approximately E-shaped radial cross-section, the outer arms of the E having a sinuous configuration and terminating in convex portions.

7. The combination as defined in claim 3 wherein said cavity is formed by the opposing flat faces of two flanges, said flanges being separated by a plate having a V-shaped recess on the inner surface thereof, into which said metallic sealing ring is compressed.

8. The combination as defined in claim 3 wherein said last mentioned metallic ring is an integral part of one of said flanges.

9. The combination as defined in claim 3 wherein said last mentioned metallic ring is separate from both of said flanges.