CORIOLIS MASS FLOWMETER

摘要

The invention relates to a Coriolis mass flowmeter comprising a vibration-type measuring sensor (1) comprising at least one measuring tube (10) through which a medium can flow during operation. During operation, the measuring tube moves by mechanical vibrations, especially bending vibrations, by means of an exciter arrangement (40). The Coriolis mass flowmeter also comprises a sensor arrangement (50) for generating vibration measuring signals (sl, s2) representing inlet-side and outlet-side vibrations of the measuring tube (10). Flowmeter electronics (2) controlling the exciter arrangement generate an intermediate value (X'm) which is derived from the vibration measuring signals (s1, s2) and represents an uncorrected mass flow, and an exciter current (iexc) driving the exciter arrangement. An intermediate value (X2) is derived from the exciter current and/or from part of the exciter current (iexc), said value corresponding to a dampening of the vibrations of the measuring tube (11), dependent on an apparent viscosity and/or a viscosity-density product of the medium guided in the measuring tube (11). Furthermore, a correction value (XK) for the intermediate value (X'm) is generated using the intermediate value (X2) and a viscosity measuring value (Xeta) that is determined previously or during operation and corresponds to a viscosity of the medium guided in the measuring tube and/or a pre-determined reference viscosity. On the basis of the intermediate value (X'm) and the correction value (XK), the flowmeter electronics can then generate an accurate mass flow measuring value (Xm).