Double toric sealing ring

Abstract

A flexible double toric sealing ring comprising two toric sealing ring sttures 2, 3 which ensure, respectively, a static seal and a dynamic seal. A counter ring is mounted radially on the second sealing ring structure and floats with it to allow self centering of the arrangement with respect to the valve seat. A sealing membrane 8 presents an elastically deformable structure 12 interconnecting the two sealing ring structures 2 and 3 while partially covering them. The two sealing ring structures 2, 3 are mounted on opposite sides of the middle section 11 of membrane 8. This double toric sealing ring can be advantageously applied to a butterfly valve.

What is claimed is: 
     
       1. A flexible double toric sealing ring comprising first and second sealing ring structures 2, 3, positioned about a common concentric axis, which ensure respectively a static seal and a dynamic seal, a counter ring which absorbs the compressive forces at the valve seat and also distributes contact pressure along the circumference, said counter ring movably mounted around the second sealing ring structure to allow self-centering of the sealing ring structure on the valve seat, and a sealing membrane, having an elastically deformable part, which interconnects the two sealing ring structures while partially covering them, said double toric sealing ring being characterized by said sealing membrane having one lateral side facing in a first direction along said common concentric axis and having an opposite lateral side facing in a second direction, opposite said first direction, along said common concentric axis, and by the placement of the two sealing ring structures on opposite lateral sides of the middle section of the membrane. 
     
     
       2. A flexible double toric sealing ring comprising first and second sealing ring structures 2, 3, which ensure respectively a static seal and a dynamic seal, a counter ring which absorbs the compressive forces at the valve seat and also distributes contact pressure along the circumference, said counter ring movably mounted around the second sealing ring structure to allow self-centering of the sealing ring structure on the valve seat, and a sealing membrane, having an elastically deformable part, which interconnects the two sealing ring structures while partially covering them, said double toric sealing ring being characterized in that said membrane 8 has a general S shape with a middle section, said middle section having a semi-circular form 12 which partially promotes the elastically deformable quality of the membrane 8, and further characterized by the placement of the two sealing ring structures on opposite sides of the middle section of the membrane. 
     
     
       3. A flexible double toric sealing ring according to claim 2, characterized in that the membrane 8 envelops sealing structure 3 and forms a partial double layer at the middle section of said membrane 8. 
     
     
       4. A flexible double toric sealing ring according to claim 1, constructed at least partially of metal. 
     
     
       5. A flexible double toric sealing ring according to claim 1, mounted in a butterfly valve. 
     
     
       6. A simplified mounting of a double toric sealing ring according to claim 2, in a butterfly valve comprising, first, a body 16 having a central passage 17 having one or more protuberances 18, one side having a steep face 20 which is preferably perpendicular to the axis of the aforesaid passage 17, and secondly, a butterfly closure member 21 pivotally mounted in said body which closes against the sealing ring structure 3 at the end of the closure movement, after a movement tangential to or parallel to the main axis of symmetry of the valve seat, characterized in that it comprises: first and second annular grooves in the said steep face 20, a first groove 25 having oblique inner side walls for receiving the first sealing ring structure 2, and a second groove 26 for receiving the semi-circular form 12 at the sealing membrane 8, and   an annular part 27 with an exterior diameter substantially equal to the diameter of the passage 17 of body 16, the side of said annular part associated with the steep face 20 functioning to restrain the first sealing ring structure 2, and forming with said steep face 20 an annular cavity 31 in which the counter ring 14 is mounted along with the second sealing ring structure 3, and   a retaining member for exerting on said annular part an axial force in the direction of the said steep face 20, and for retaining it in position in the passage 17 of body 16.   
     
     
       7. A flexible double toric sealing ring according to claim 1, characterized in that the membrane 8 envelops sealing ring structure 3 and forms a partial double layer at the middle section of said membrane 8. 
     
     
       8. A simplified mounting of a double toric sealing ring according to claim 1, in a butterfly valve comprising, first, a body 16 having a central passage 17 having one or more protuberances 18, one side having a steep face 20 which is preferably perpendicular to the axis of the aforesaid passage 17, and secondly, a butterfly closure member 21 pivotally mounted in said body which closes against the sealing ring structure 3 at the end of the closure movement, after a movement tangential to or parallel to the main axis of symmetry of the valve seat, characterized in that it comprises: first and second annular grooves in the said steep face 20, a first groove 25 having oblique inner side walls for receiving the first sealing ring structure 2, and a second groove 26 for receiving the semi-circular form 12 at the sealing membrane 8, and   an annular part 27 with an exterior diameter substantially equal to the diameter of the passage 17 of body 16, the side of said annular part associated with the steep face 20 functioning to restrain the first sealing ring structure 2, and forming with said steep face 20 an annular cavity 31 in which the counter ring 14 is mounted along with the second sealing ring structure 3, and   a retaining member for exerting on said annular part an axial force in the direction of the said steep face 20, and for retaining it in position in the passage 17 of body 16. .Iadd.   
     
     
       9.  A butterfly valve comprising, body means 16, flow passage means 17 through the body means, protuberance means 18 on said body means projecting inwardly into said flow passage means, seal ring means 2, 3 in said flow passage means 17 and engaging said protuberance means 18, butterfly closure means 21 engageable with said seal means 2,3 to control flow through said body means 16, annular part means 27 in said flow passage means 17 engaging said sealing ring means 2, 3, annular fastening means 28 in said flow passage means 17 adjacent said annular part means 27, retainer ring means 36 releasably secured to said body in said passageway means, expander means 34 extending between said annular part means 27 and said fastening means 28 and when expanded forcing said fastening means 28 against said retainer ring means 36 and said annular part means 27 against said seal ring 2, 3 to hold said seal ring means 2, 3 in engagement with said protuberance means. .Iaddend. .Iadd.10. The valve of claim 9 wherein said expander means 34 is provided by screws threaded in said fastening means 28 and bearing against said annular part means 27. .Iaddend.