Inflated seal for large annular openings

A seal for a large annular opening between two generally cylindrical surfaces. The seal being formed of a first portion having a base ring and a toroidal shaped arcuate portion extending from the central portion of the base ring, a lip portion extending radially inwardly and toward the high pressure portion from the end of the arcuate portion and a second portion having a base ring, both base rings being affixed to one of the cylindrical surfaces. The second base ring being disposed on the high pressure side of the first base ring and there being ribbons extending between the first portion and the second portion. The ribbons being made of a high strength material and being disposed on a predetermined pitch and attaching the free end of the first portion to the second portion to prevent the arcuate toroidal shaped portion from inverting, even though it is compliant and deforms substantially under pressure.

BACKGROUND OF THE INVENTION 
This invention relates to seals and more particularly to a seal for a large 
annular opening. 
When sealing large annular openings, one of the problems is preventing the 
seal from inverting or flipping through when high pressures are being 
sealed. Another problem is keeping the cylindrical surfaces between which 
the seal is disposed concentric. 
Elastomer seals for large annular openings are described in U.S. Pat. No. 
4,033,593, and the following applications filed by the common assignee, 
one entitled "Large Annular Segmented Seal with Lock Portions", Ser. No. 
451,585, filed Dec. 20, 1982, another Ser. No. 366,458, filed Apr. 8, 1982 
and entitled "Segmented Annular Seal". 
SUMMARY OF THE INVENTION 
A seal for a large annular opening between two generally cylindrical 
surfaces, when made in accordance with this invention, comprises a first 
base portion affixed to one of the cylindrical surfaces, an arcuate 
toroidal portion extending from the first base portion in such a manner 
that a concave side thereof is disposed on the high pressure side of the 
seal, a second base portion affixed to the one cylinder on the high 
pressure side of the first base portion and ribbons formed from a high 
strength material spaced on a predetermined circumferential pitch between 
the toroidal portion and second base portion and embedded therein to form 
a compliant seal which will not invert and which has substantial 
self-centering characteristics.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail and in particular to FIGS. 1, 2 and 
3, there is shown a seal for a large annular opening between two generally 
cylindrical surfaces 3 and 5. The seal 1 comprises a first base portion 7 
affixed to one of the cylindrical surfaces 3. Extending from the first 
base portion 7 is an arcuate portion 9 having a generally toroidal shape 
so disposed that a concave side thereof is on the high pressure side of 
the seal 1. Extending radially inwardly from the arcuate or toroidal 
shaped portion 9 and toward the high pressure side of the seal is a frusto 
conical portion 11 forming a lip which abuts the other cylindrical surface 
5. 
A second base portion 17 is also affixed to the cylindrical surface 3 
forming a circumferential ring. Extending between the second base portion 
17 and the arcuate toroidal shaped portion 9 are a plurality of ribbons 19 
spaced on a predetermined circumferential pitch. The ribbons 19 are 
embedded in the arcuate toroidal shaped portion 9 and the second base 
portion 17 and are made of a material with high tensile strength such as 
an aromatic polyamide which is available under the trade name of 
KEVLAR.RTM.. 
A circumferential hump 23 is disposed adjacent the juncture of the arcuate 
toroidal shaped and frusto conical portions 9 and 11 on the high pressure 
side thereof. The ribbons 19 extend from the arcuate toroidal shaped 
portion 9 adjacent the hump 23. 
As shown in FIG. 2, when the cylindrical surfaces 3 and 5 are eccentrically 
disposed, the pressure on the high pressure side of the seal exerts a 
force on a portion of the cylindrical surface 5, tending to move the 
cylindrical surface 5 to a concentric position within the cylindrical 
surface 3. 
The large annular seal hereinbefore described advantageously provides a 
seal which easily deforms under pressure to form a tight seal but one 
which will not invert due to the ribbons which also distribute the load 
between the two base portions 7 and 17 in such a manner that the 
attachment between the base portions 7 and 17 and the cylindrical surface 
3 are subjected to shear rather than bending moments; the latter would 
tend to peel the base portions from the cylindrical surfaces to which they 
are affixed and also provides a self-centering resulting force which tends 
to center the cylindrical surface 5 when it becomes eccentrically 
disposed.