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. 04, 1992
Filed:
Apr. 20, 1990
Robert L Leon, Maple Glen, PA (US);
Liberty Technology Center, Inc., Conshohocken, PA (US);
Abstract
A system to determine the position of an electrically conductive element movably positioned in a housing, like a metal disc in a check valve, includes an A.C. electromagnet positioned in close proximity to the valve casing and the disc. The magnet is excited with an A.C. voltage to generate a magnetic field which penetrates the casing and the disc. The magnetic field is detected by a sensor. A.C. current and voltage signals from the electromagnet and a magnetic field signal from the sensor are presented to a processor portion of the system. The processor portion digitizes, amplitude and phase modulates each of the three signals and generates four traces: A.C. current amplitude, magnetic field amplitude, A.C. current phase and magnetic field phase. The latter two traces are derived with respect to an A.C. voltage phase signal. Comparable baseline signals previously gathered for the valve are stored. One to four of the traces are displayed, with or without the corresponding baseline trace, for determination of disc position.