| 摘要 |
A self-cleaning valve has its closure member rotated against a valve seat during closing, by an externally threaded spindle rotated by an actuator. The spindle has a threaded portion screwed through an internally threaded collar which is pressed by a spring towards the valve seat. When the member engages the valve seat further rotation of the spindle causes the collar to ride up the spindle against the spring bias which maintains the closing force on the member while allowing it to rotate to clean the closing surfaces.
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