| 摘要 |
The invention relates to a fluid flow control valve of the type in which flow through the valve is controlled by movement of a chamber wall caused by fluid flowing into the chamber through a restricted inlet and a cleaning element is provided to clean the inlet. In this invention, the cleaning element is longer than the restricted inlet and is movable between a first position in which it does not extend through the restricted inlet and a second position in which it extends completely through the restricted inlet. The cleaning element is a rod-like element of self-supporting flexible synthetic plastics material and has a limited inherent rigidity enabling it to force dirt and scale from the restricted inlet.
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