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US 7,730,780 B2Granted
Level switch and method for detecting the fill level of a medium in a container
AssigneeKrohne AG
InventorsJef Neven, Vincent Pichot
Life of this patent
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AssigneeKrohne AG
InventorsJef Neven, Vincent Pichot
Estimating the term…
A level switch detects the fill level of a medium in a container and transmits a switch signal corresponding to the detected level. The level switch incorporates a signal generator for generating an electromagnetic signal, a measuring circuit, and a reference circuit into which the electromagnetic signal can be fed. The measuring circuit is so configured and positioned that the signal fed into the measuring circuit changes as a function of whether or not the measuring circuit is surrounded by the medium, while the reference circuit is so configured and positioned that the signal fed into the reference circuit remains unaffected by the fill level of the medium. A tap at a specific point on the measuring circuit collects the measuring voltage, a tap at a specific point on the reference circuit collects a reference voltage, and a voltage comparator compares the measuring voltage with the reference voltage and emits a comparison-derived switch signal. This permits the dependable detection of a specific level of the medium in the container while essentially eliminating errors due to changes in extraneous parameters such as temperature fluctuations. A method for detecting the fill level of a medium in a container employing the switch is also disclosed.
A level switch for detecting the fill level of a medium in a container and for transmitting a switch signal representative of that level, incorporating a signal generator for generating at least one electromagnetic signal, a measuring circuit as well as a reference circuit into each of which an electromagnetic signal generated by the signal generator can be fed, said measuring circuit being so configured and positioned that the electromagnetic signal fed into the measuring circuit undergoes a change that depends on whether or not the measuring circuit is surrounded by the medium, while the reference circuit is so configured and positioned that the electromagnetic signal fed into the reference circuit remains unaffected by the level of the medium, with a measuring-voltage tap at a specific point on the measuring circuit permitting the determination of the measuring voltage and a reference voltage tap at a specific point on the reference circuit permitting the determination of the reference voltage, and with a voltage comparator serving to compare the measuring voltage with the reference voltage and to emit a comparison-derived switch signal.
A method for detecting the fill level of a medium in a container and for emitting a switch signal that is representative of that level, for which an electromagnetic signal is fed into a measuring circuit and, respectively, into a reference circuit, said measuring circuit is so configured and positioned that the signal fed into the measuring circuit changes as a function of whether or not the measuring circuit is surrounded by the medium, said reference circuit is so configured and positioned that the signal fed into the reference circuit remains unaffected by the fill level of the medium, a measuring voltage is collected at a specific point on the measuring circuit, and a reference voltage is collected at a specific point on the reference circuit, the measuring voltage and the reference voltage are compared and a comparison-derived switch signal is emitted.
Dependencies are inferred from the claim text.