Patent ID: 7040181

Claim:
A coriolis mass flow measuring device, especially a Coriolis mass flow rate/density measuring device, or a Coriolis mass flow rate/viscosity measuring device, for measuring the mass flow rate of a medium flowing in a pipeline, especially a medium of two or more phases, which Coriolis mass flow measuring device comprises: a vibratory transducer and measuring device electronics electrically coupled to said vibratory transducer, wherein said vibratory transducer has: at least one measuring tube to be interposed in the pipeline, especially an essentially straight measuring tube, for guiding the medium to be measured, in communication with the connected pipeline, an exciter arrangement acting on said at least one measuring tube for causing said at least one measuring tube to vibrate with lateral oscillations, especially bending oscillations, at least at times, and/or at least in part, during operation, and a sensor arrangement for registering vibrations of said at least one measuring tube, which delivers at least one, first oscillation measurement signal (s 1 ) representing oscillations of said at least one measuring tube at the inlet end and at least one, second oscillation measurement signal (s 2 ) representing oscillations of said at least one measuring tube at the outlet end, and said measuring device electronics delivers, at least at times, an exciter current (i exc ) driving the exciter arrangement and, at least at times, a mass flow rate measurement value (X m ) representing a mass flow rate to be measured, produces a first intermediate value (X′ m ) derived from the oscillation measurement signals (s 1 , s 2 ) and corresponding to the mass flow rate to be measured and/or to a phase difference between the two oscillation measurement signals (s 1 , s 2 ), as well as a second intermediate value (X 2 ) derived from the exciter current (i exc ), and/or from a component of the exciter current (i exc ), and corresponding to a damping of the oscillations of said measuring tube, especially a damping dependent on an apparent viscosity, and/or a viscosity-density product, of the medium guided in said at least one measuring tube, and uses the second intermediate value (X 2 ) and a viscosity measurement value (X η ) predetermined, or determined during operation, especially by use of the transducer and/or the measuring device electronics, and corresponding to a viscosity of the medium guided in said at least one measuring tube and/or to a previously supplied, reference viscosity, to produce a correction value (X K ) for the first intermediate value (X′ m ), and, on the basis of the first intermediate value (X′ m ) and the correction value (X K ), to produce the mass flow rate measurement value (X m ).