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:
Apr. 26, 1988
Filed:
Apr. 02, 1986
William H Slavik, Palos Hills, IL (US);
Nuvatec, Inc., Downers Grove, IL (US);
Abstract
A monitoring unit for remotely monitoring liquid levels in a container includes a common probe, a reference probe, and four sensing probes, each mounted to the container in electrical contact with liquid within the container. A liquid level sensing unit measures resistance between the common probe and the reference probe and uses the measured resistance as a threshold to determine which of the sensing probes is in contact with liquid in the container. In this way, the sensing unit is made substantially independent of the resistivity of the liquid in the container. The sensing unit is connected to an evaluating unit by a single conductor, and the sensing unit draws a variable amount of current through the conductor in accordance with the number of sensing probes in contact with liquid in the container. The conductor thus supplies power to the sensing unit and also transmits information from the sensing unit to the evaluating unit. The evaluating unit includes a current-to-voltage converter which generates voltage proportional to the current drawn by the sensing unit. A display circuit displays an indication of the resulting voltage.