| 摘要 |
A fluid handling machine having a shaft, a radially disposed housing, and a backup seal. During normal operation, the backup seal is concentric with and radially spaced from the shaft. The backup seal includes a first annular portion located adjacent the backup seal chamber and a second annular portion preferably made of carbon graphite. The backup seal is configured to engage the housing such that when the fluid pressure in the backup seal chamber exceeds a predetermined level, a sufficient axial force is applied to the first annular portion and transmitted therethrough to the second annular portion to cause the second annular portion to close radially into sealing engagement with the shaft.
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