| 摘要 |
<p>A fire-safe valve structure has a metal seat with an annular groove therein in which a resilient sealing ring is positioned in face-to-face contact with a valve member movable between open and closed positions. The annular groove has an annular space behind the resilient sealing ring to permit displacement of the sealing ring. A fusible material which melts at a predetermined high temperature is associated with the annular space and holds the sealing ring in contact with the valve member. Upon melting of the fusible material and subsequent metering thrugh a metering opening, the sealing ring is displaced within the annular space and the valve member moves into a tight metal-to-metal contact with the metal seat.</p> |
