| 摘要 |
A butterfly valve is disposed in a valve body for sealing engagement with a resilient seat ring disposed in a tapered groove defined by the valve body and a retaining ring. A metallic back-up ring is disposed between two legs of the seat ring to support a sealing portion thereof when the valve is closed. Flanges on the legs retain the seat ring together with the backup ring in the groove. Parallel walls at the bottom of the groove insure seat ring and back-up ring retention. An "O" ring is disposed between the back-up ring, the flanges and the groove bottom and pressurized fluid passageways are provided to produce a two-way pressure assist for sealing.
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