| 摘要 |
<p>A combination shut-off pressure surge relief and reverse flow prevention valve is disclosed comprising manually rotatable valve stem with a movable valve member at its lower end that is biased towards its closed position by a spring so that flow in a normal direction will open the valve but reverse flow is prevented. The pressure surge relief valve is completely enclosed within the rotatable valve stem and comprises a spring loaded slidable piston that is movable by abnormal pressure surges to expose relief ports for allowing controlled leakage under surge conditions. The leakage from the ports is deflected by a surrounding shroud on the handle of the valve stem.</p> |
