| 摘要 |
A mass flow measurement and control device includes an enclosure with a Coriolis mass flowmeter situated therein. The Coriolis mass flowmeter has a flow-tube made of a high-purity plastic material, a driver coupled to the flow tube for vibrating the flow tube, and a pickoff coupled to the flow tube for sensing Coriolis deflections of the vibrating flow tube. A pinch valve includes an elastomeric tube made of a high-purity plastic material in fluid communication with the flow tube. An actuator with a ram operatively connected thereto is situated adjacent the elastomeric tube, and a reference surface is positioned generally opposite the ram such that the elastomeric tube is squeezable between the ram and the reference surface. A controller may also be provided, which receives an output signal from the Coriolis flowmeter and provides a control output signal to the pinch valve actuator in response to the flowmeter output signal and a setpoint signal. |
