| 摘要 |
Several Radial Mode Coriolis mass flow rate meter geometries and electronic circuits are described that may be made to be sensitive to pressure or density changes. In one embodiment, the meter comprises: (1) a flow conduit for containing a fluid having a physical characteristic, the fluid adapted to flow in the conduit at an unknown rate, (2) a drive circuit for creating a vibration in the flow conduit, the fluid altering the vibration as a function of the physical characteristic and the flow rate, (3) a detector circuit for measuring the altered vibration at a working point and producing a signal representing an uncompensated mass flow rate of the fluid and (4) a computation circuit for calculating a compensated mass flow rate of the fluid proportional to the uncompensated rate by 1/ OMEGA 1n, where OMEGA 1 is a driven natural frequency of the flow conduit and n is a number chosen as a function of the working point, the compensated rate thereby reduced of effects of the physical characteristic. A unique mathematical algorithm is also described that allows for a much wider variety of design geometry while maintaining insensitivity to pressure or density without having to measure or compensate for either. In addition, a method is described that allows for the accurate measurement and compensation of both pressure and density.
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