Coupling devices

Claim 1

IN COUPLING DEVICES OF THE TYPE EMPLOYED FOR MAKING CONNECTION BETWEEN ALIGNED FLOW PASSAGES, A STRUCTURE HAVING A PORTION AFORMING AN ANNULAR PLANAR CLAMPING FACE AND A FLOW PASSAGE SURROUNDED BY SAID FACE, AN ANNULAR RECESS IN SAID PORTION AND OPENING THROUGH THE PLANE OF SAID FACE, SAID RECESS AN VIEWED IN SECTION BEING DEFINED BY OUTER AND INNER PERIPHERAL SURFACES THAT ARE CONVERGENT TOWARD SAID PLANE AND A BOTTOM SURFACE THAT IS GENERALLY PARALLEL TO SAID PLANE, AND A PAIR OF NESTED CONCENTRIC RESILIENT SEAL RINGS DISPOSED IN SAID RECESS AND IN DIRECT PHYSICAL CONTACT WITH EACH OTHER, EACH RING WHEN RELAXED HAVING A RADIUS IN SECTION THAT IS LESS AND A DIAMETERS GREATER THAN THE DEPTH OF THE RECESS, THE DIAMETERS OF THE TWO RINGS IN SECTION BEING GREATER THAN THE RADIAL DISTANCE BETWEEN SAID INNER AND OUTER PERIPHERAL SURFACES WHEREBY THE RINGS ARE COMPRESSED WHEN POSITIONED IN SAID RECESS, SAID RINGS FORMING MEANS FOR MAKING SEALING CONTACT WITH THE ANNULAR CLAMPING FACE OF A COMPLEMENTARY COUPLING PART, SAID STRUCTURE COMPRISING A FLANGE HAVING SAID FIRST NAMED ANNULAR CLAMPING FACE TOGETHER WITH A SEPARATE ANNULAR PORTION FITTED CONCENTRICALLY WITHIN THE FLANGE AND HAVING AN ANNULAR END SURFACE SUBSTANTIALLY COINCIDENT WITH THE PLANE OF SAID CLAMPING FACE, SAID RECESS BEING FORMED IN PART IN THE FLANGE AND IN PART IN SAID ANNULAR PORTION, THE CIRCULAR JUNCTION LINE BETWEEN THE FLANGE AND THE ANNULAR PORTION BEING LOCATED INTERMEDIATE THE AREAS OF CONTACT BETWEEN THE SEALING RINGS AND SAID BOTTOM SURFACE, SAID SEAL RINGS HAVING AREAS OF SEALING CONTACT WITH THE BOTTOM SURFACE FORMED ON THE FLANGE AND THE PORTION OF THE BOTTOM SURFACE FORMED ON SAID ANNULAR PORTION RESPECTIVELY.