Patent ID: 6722630
Filing Date: 2004-04-20
Classification: F16K

Abstract:
A shut-off device comprising a single-part housing insertable in a pipeline, and a butterfly valve swivellable by an eccentrically pivoted drive shaft wherein said butterfly valve in its closed position is sealed off from the housing and from the pipe connection, by a distensible entropy-elastic annular seal of U-shaped cross section to which fluid can be applied, with said annular seal being held by a backup ring on a face of the housing by several screws, characterised in that by means of two annular projections (11, 12) which face each other, the annular seal (7) engages one annular groove (13, 14) each in each face (15, 16) of the backup ring (6) so as to provide a seal; in that each of the lateral external areas (17, 18) of said annular seal (7) comprises an integrated projecting sealing ring (19, 20), in that an annular groove is formed around the internal circumferential area of the backup ring (6), said annular groove providing for the formation of a fluid pressure chamber (22) when said backup ring (6) and said annular seal (7) are assembled, in that a fluid connection pipe (24) penetrates said backup ring (6), and directly leads to said annular groove, said fluid connection pipe (24) sealed off from the external atmosphere, thereby allowing said fluid pressure chamber (22) to be pressurized to exert pressure on said annular seal (7), and in that said several screws are conventional socket screws.