| 摘要 |
<p>A mass flow measurement and control device (100) includes an enclosure (101) with a Coriolis mass flowmeter (50, 112) situated therein. The Coriolis mass flowmeter (50, 112) has a flow-tube made of a high-purity plastic material, a driver (D) 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 (52). A pinch valve (110, 120) includes an elastomeric tube (126) made of a high-purity plastic material in fluid communication with the flow tube. An actuator (122) with a ram (124) operatively connected thereto is situated adjacent to the elastomeric tube (126), and a reference surface (128) is positioned generally opposite the ram such that the elastomeric tube is squeezable between the ram and the reference surface. A controller (114) may also be provided, which receives an output signal from the Coriolis flowmeter (50, 112) and provides a control output signal to the pinch valve actuator (112) in response to the flowmeter output signal and a setpoint signal.</p> |
