| 摘要 |
In accordance with the present invention, there is provided a bi-directional shut-off trim for a valve which possesses the functional attributes of a pilot operated trim and a balanced trim through the integration of a spring loaded check valve into a pilot trim. In forward flow isolation, the bi-directional shut-off trim of the present invention acts as a normal pilot operated trim. In reverse flow, the check valve of the shut-off trim opens to balance the pressure on either side of the plug thereof.
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