| 摘要 |
The present invention relates to a butterfly valve. In order to ensure sealed closure when the butterfly 6 of the valve is subjected to an over-pressure in the opposite direction to a preferred direction of flow 4 of the fluid, there is provided, in compensation, an external peripheral face 10 of the butterfly 6, which converges in the downstream direction, a ring 19 with sealing lip 29 mounted slidably in the body 1 of the valve, parallel to the predetermined direction 4 and having a surface 42 exposed in the downstream direction so that it then comes to press in a sealed fashion on the external peripheral face 10 of the butterfly 6; means 35 elastically force the ring 19 towards a limiting downstream position which constitutes its normal operating position. <IMAGE>
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