In-line measuring devices and method for compensation measurement errors in In-line measuring devices

A method for measuring at least one parameter of a two-, or multi-phase mixture flowing in a pipeline, by means of an inline measuring device including a measurement transducer of the vibration-type, and measuring device electronics electrically coupled with said measurement transducer, said mixture consisting of at least one first mixture phase and at least one second mixture phase, said method comprising the steps of:

• conducting the mixture to be measured within at least one measuring tube of said measurement transducer, with the measuring tube being in communication with the pipeline;
• feeding an exciter arrangement with an excitation signal, said exciter arrangement being adapted to impart motion to said at least one measuring tube and vibrating said at least one measuring tube, said excitation signal including at least a first excitation signal component corresponding to a first one of a plurality of natural eigenmodes of said at least one measuring tube conducting said mixture;
• sensing vibrations of the measuring tube conducting said mixture and generating at least one oscillation measurement signal representing oscillations of the vibrating measuring tube, said at least one oscillation measurement signal including at least a first measurement signal component corresponding to said first one of said plurality of natural eigenmodes of the at least one measuring tube conducting said mixture,
• using at least said first measurement signal components and said excitation signal for generating at least one measured value representing said at least one parameter to be measured.

A method for determining a concentration of at least one phase of a mixture consisting of at least one first mixture phase and at least one second mixture phase, said mixture flowing in a pipeline, which is in communication with at least one measuring tube of an inline measuring device, said method comprising the steps of:

• conducting said mixture within said at least one measuring tube;
• causing at least one of said first and second mixture phases, currently within said at least one measuring tube, to move relative to said at least one measuring tube, said relative motions of said at least one of the first and second mixture phases stimulating said at last one measuring tube to vibrate within at least one of a plurality of instantaneous natural eigenmodes of said at least one measuring tube conducting said mixture;
• sensing vibrations of said at least one measuring tube and generating at least one oscillation measurement signal representing oscillations of the vibrating at least one measuring tube, said at least one oscillation measurement signal including at least one signal component corresponding to one of a plurality of natural eigenmodes of said at least one measuring tube conducting said mixture, said natural eigenmode being stimulated due to said relative motion of said at least one of the first and second mixture phases to said measuring tube;
• and
• using said at least one signal component of the oscillation measurement signal, for generating at least one concentration value representing a concentration of at least one of said first mixture and said second phases within the mixture.