| 摘要 |
A single tube Coriolis flowmeter having a flow tube (901) and balance bar (902) vibrated in-phase opposition. Material flow through the vibrating flow tube induces Coriolis deflections in the flow tube which, via brace bars (913), induces in-phase Coriolis like deflection in the balance bar. A balance bar resonator (908) coupled to the balance bar is excited to vibrate in a rotational mode out of phase with respect to the balance bar. The vibration of the balance bar resonator increases the accuracy of the flowmeter output data by 1) increasing meter flow sensitivity by applying torque to the balance bar to reduce its in-phase Coriolis like deflections; 2) by applying torque to the flow tube via the balance bar to reduce shaking of the flowmeter; and 3) causing the flowmeter to have a flat calibration factor with respect to changed in material density by the provision of: apparatus (913) that changes the vibrational amplitude ratio of the flow tube and the balance bar in response to said detection of a change in material density; apparatus (909, 913) that changes the material flow sensitivity of the Coriolis flowmeter in a first direction in response to a change in vibrational amplitude ratio: apparatus (909) that alters the vibrational amplitude of the balance bar resonator to change the material flow sensitivity in a second direction in response to a change in resonant frequency; the changes in flow sensitivity in the first direction and in the second direction are effective to achieve a flow calibration factor of the Coriolis flow meter.
|
