The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 02, 1999
Filed:
Dec. 17, 1996
Stuart R Ball, Yukon, OK (US);
Akzo Nobel N.V., Arnhem, NL;
Abstract
A sensor detects when a probe contacts liquid in a container due to a change in frequency of a probe oscillator. The sensor can have its output compared to a reference level to determine the presence or absence of liquid wherein the reference level is changed to follow the output of the detector. In one embodiment, it can be determined that liquid has been contacted when a count has been reached several times in a row (the count being a function of the probe output and changeable). In another embodiment of the invention, it can be determined that liquid has been contacted when a count has been reached within a certain threshold several times in a row, while still having the reference count change to follow the probe output (regardless of the threshold). A digital counter can be provided to determine the frequency of the probe oscillator. A reference counter can also be provided to tune the count (frequency) from the probe oscillator counter to thereby compensate for drift. And, the adjustable detection threshold permits control of the sensitivity by changing the parameters of the circuit.