Coriolis mass flowmeter

Abstract

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).

Description

technical field [0001] The invention relates to a Coriolis mass flow / density meter for in particular two-phase or multi-phase media flowing in pipelines and a method for generating measured values ​​representative of mass flow. Background technique [0002] In process measurement and automation technology, in order to measure the physical parameters of the medium flowing in the pipeline, such as mass flow, density and / or viscosity, such online measuring instruments, especially Coriolis mass flow measuring instruments, are often used. Vibration-type measuring transducers in a medium-conducting pipe through which the medium flows during operation and the measuring and operating circuits connected to it generate reaction forces in the medium, e.g. Coriolis force corresponding to mass flow, corresponding to density The inertial forces or frictional forces corresponding to the viscosity, etc., from which the measuring device obtains one or more measurement signals representing ...

AI Technical Summary

Problems solved by technology

However, this is a very special solution which can only be realized in very limited cases, especially in measurement technology in industrial processes

On the one hand, in this case the pipe into which the measuring transmitter is to be installed may have to be fixed to the transmitter and not vice versa, which means additional costs for the user in creating the measuring position

On the other hand, as already mentioned, the measuring tube may be bent, so that the problem cannot be solved by changing the orientation of the installation

In this regard, it has been found that the mentioned deterioration of the measurement signal is practically not significantly avoided by using vertically mounted straight measuring tubes

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