Fischer & Porter Company

Werner Marchewka

Klaus Schafer

Albert Seebode

Jorg Herwig

Karl-Heinz Rackebrandt

Joachim Hagemann

Michael Tzfeld

Hans J Dettmer

Apparatus for measuring the flow of a fluid medium which flows upward through a substantially vertically mounted tube section having a suspended body in the tube section. The vertical position of the suspended body depends on the intensity of the flow. Movement of a magnet, movable with the suspended body, is sensed by a unit which includes a Hall sensor and an electronic evaluation circuit, responsive to the Hall sensor output, develops an output signal corresponding to the flow of the medium.

Apparatus for measuring the flow of a fluid medium

An electromagnetic flowmeter whose primary includes a flow tube through which the fluid to be metered is conducted to intersect a magnetic field and thereby induce a voltage therein that is transferred to electrodes to produce an electrode signal as a function of flow rate, which signal includes a noise voltage. The electrode signal is applied to the input amplifier of a secondary whose output is fed to one input of a summing stage, the output of which is fed to a range amplifier that yields a test voltage, the input and range amplifiers producing offset voltages. To compensate for the noise and offset voltages, a compensation voltage is derived from the test voltage and applied to the other input of the summing stage. This compensation voltage is produced only when the test voltage exceeds a predetermined threshold value.

Noise and offset voltage-compensated electromagnetic flowmeter

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Neu-Eichenberg, Germany

Werner Marchewka