| 摘要 |
<p>A valve seat especially adapted for a butterfly valve is provided which is formed both of metal and <<soft>> material so as to furnisch a <<bubble tight>> seal in normal operating conditions and a metal-to-metal seal in fire situations. The seat is uniquely constructed and is permanently deformed by the disc or closure member of the valve to form a precise size and configuration corresponding to the size and configuration of the disc.</p> |
