Fluid interface detector
AssigneeEmhart Industries, Inc.
InventorsGeorge R. French, John S. Oliver
Life of this patent
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Abstract
A fluid interface detector includes a circuit for detecting the presence of one of two fluids to establish an interface level between the two fluids. The detection circuit produces an output signal having a variable pulse width determined by which of the two fluids is present. A reference signal of a predetermined pulse width is compared to the pulse width of the output signal of the detection circuit by a comparator which produces an output signal indicating which of the two fluids is present. The detection circuit includes at least one capacitive sensing device and in accordance with the present invention may include a plurality of capacitive sensing devices to detect a fluid interface at various levels.
Claims20
A fluid interface detector, comprising a circuit for detecting the presence of at least two fluids to establish an interface level between the fluids, the circuit producing an output signal of varying duration determined by which fluid is present, at least one circuit for producing at least one reference signal of a predetermined duration, and means for comparing the duration of the output signal of the detection circuit to the predetermined duration of the reference signal and producing a signal indicative of which fluid is present.
Dependencies are inferred from the claim text.