Vibration-type measuring sensor for conduction measurements in media flowing inside two medium lines, and in-line measuring device equipped with a measuring sensor of this type

Abstract

A measurement pickup includes at least four measuring tubes for conveying media to be measured. Each measuring tube has a first in-/outlet end and a second in-/outlet end. During operation, the measuring tubes vibrate, at least at times, especially simultaneously. The measurement pickup further includes an electromechanical exciter mechanism causing the measuring tube to vibrate, as well as a sensor arrangement reacting at least to local vibrations of the measuring tubes for producing at least one measurement signal influenced by vibrations of the measuring tubes. Of the at least four measuring tubes, two measuring tubes are, at least at times, inserted into the course of a first medium-line such that each of these two measuring tubes simultaneously conveys, in each case, a partial volume of a medium flowing through the first medium line, and two other measuring tubes of the at least four measuring tubes are, at least at times, inserted into the course of a second medium line such that each of these two measuring tubes simultaneous conveys, in each case, a partial volume of a second medium flowing through the second medium line. The measurement pickup can thus, on the one hand, have two media flowing through it, which differ measurably from one another in at least one physical property, for example mass flow rate, medium density and/or medium temperature, while having, on the other hand, despite the different media, a good zero-point stability.

Description

technical field [0001] The invention relates to a measuring transducer for measuring a medium flowing in two, in particular separate, pipes, and an in-line measuring instrument with such a measuring transducer. Background technique [0002] In order to measure or detect process variables of media flowing in pipelines, especially for detecting flow and / or rheological measurement variables, such in-line measuring instruments are often used, which utilize vibration-type measuring variables inserted into the pipe or housing line that guides the medium The transmitter and the measurement and operating circuits connected to it, to induce reaction forces in the medium flowing through the transmitter during operation, such as Coriolis force corresponding to mass flow, inertial force corresponding to density or viscosities frictional forces and from these forces a measurement signal representing the specific mass flow, viscosity and / or density of the medium is generated. In this cas...

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Problems solved by technology

[0008] However, this mainly calculation-based compensation basically only eliminates the measurement errors caused by the different oscillation amplitudes, which on the one hand result in the design of the excitation device and the sensor device as well as the design of the measuring instrument electronics and the hardware for processing the measurement signal and the increased technical complexity of the software, on the other hand, the unbalance inevitably associated with the non-uniform change in the oscillation characteristics of the measuring tube can lead to significant problems with the zero point stability of the measuring transducer, which can hardly be solved by mainly limiting Compensation measures for measurement signal processing are addressed by

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