| 摘要 |
A proportional flow control valve, for controlling fluid flow through a flexible tube, includes first and second jaws on opposing sides of the tube. An actuator drives one of such jaws for adjusting the separation distance therebetween. When the valve is open, the separation distance is small enough to partially deform the tube without significantly restricting fluid flow. When the valve is closed, the separation distance is just small enough to essentially block fluid flow. A control system controls the actuator to determine such separation distance. Such valve can be used within a level control system for controlling the thickness of a work material in a slurry form cast upon a moving belt. A fluid reservoir is disposed above the belt, and the control valve adds slurry to the reservoir. A lens disposed near the moving belt and above the reservoir is coupled by fiber optics to a remote sensor for detecting the height of the slurry. A control circuit responsive to the light sensor regulates the flow rate of the control valve.
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