Ifm Electronic Gmbh

Schaeffler Technologies Ag & Co .Kg

Markus Körber

Jürgen Weber

Walter Reichart

Christian Kreisel

Ralf Kriesen

Werner Hoch

Sebastian Liehr

A thermal flowmeter comprises a heating element thermally coupled to a flowing medium, a first temperature sensor and second temperature sensor. The first temperature sensor detects a flowing medium temperature in a region not affected by the heating element. The second temperature sensor detects a temperature of the heating element and also serves as a heating element. A control unit controls heating power of the heating element based on the difference between the detected temperatures at a predetermined time. The control unit provides a square wave signal to the second temperature sensor so that in a high phase it acts as heating element and in a low phase as a temperature sensor.

Thermal flowmeter and method having a self-heated element controlled to operate differently under high and low phases of square wave signal

A magnetoinductive flowmeter for measuring the flow rate of a flowing, conductive medium with a capacitive measuring apparatus for detecting empty pipes is provided. In order to improve the detection of empty pipes and, in particular, the capacitive coupling to the medium, the invention provides for the measuring apparatus for detecting empty pipes to comprise a sheet-like electrode in each case and a counterelectrode which form a measurement capacitance Cwhich is dependent on the medium and on the degree of filling of the measuring tube; for the measuring tube to have a wall thickness which is reduced in order to maximize the measurement capacitance Cat least in the region of the electrode and the counterelectrode; and for the measuring tube to be surrounded by a metal supporting housing, wherein, in order to maintain the pressure resistance of the measuring tube, a hollow-walled supporting body for minimizing the influence of parasitic capacitances on the measurement capacitance Cis arranged in each case in the region of the reduced wall thickness between the electrode and the inner wall of the supporting housing and between the counterelectrode and the inner wall of the supporting housing and supports the measuring tube against the supporting housing in each case.

Magnetic inductive flow meter having capacitive measuring device for empty pipe detection

A magnetic-inductive flowmeter with a nonconductive measuring tube, a magnetic field generating apparatus, two measuring electrodes conductively coupled to the medium for tapping a measuring-circuit voltage induced in the flowing medium, and with a measuring device for detecting an empty tube. Detection of an empty tube is obtained by the measuring device being an admittance measuring device having a detector, a counter-electrode, an ac signal source and an evaluation unit, the detector having an electrode connected to the ac signal source so that the electrode is exposed to an ac signal in the range of roughly 50 MHz-200 MHz and then an electrical field extends from the electrode into the medium. The electrode of the detector and the counter-electrode planiform shaped and are located essentially opposite one another on the outer surface of the measuring tube above and underneath the longitudinal axis of the measuring tube, respectively.

Magnetic-inductive flowmeter with an empty tube detecting device of an admittance measuring type

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Immenstaad, Germany

Markus Körber