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:
May. 19, 1998
Filed:
Jan. 04, 1996
John H McAdoo, McClean, VA (US);
William Catoe, Woodbridge, VA (US);
Michael W Bollen, Clifton, VA (US);
Vince Folen, Alexandria, VA (US);
Fred Volkening, Boonsboro, MD (US);
Mission Research Corporation, Santa Barbara, CA (US);
Abstract
A lubricating/hydraulic fluid condition monitor in which a coaxial microwave resonator is placed in a fluid conduit to determine changes in the chemical properties and debris concentration is disclosed. Microwave radiation is applied to the resonator for measuring the resonant frequency and resonator Q. An externally powered electric or magnetic field is used to alternately align and misalign debris in the fluid while the resonator properties are being measured. A logic unit automatically generates tables of resonant frequency and Q versus resonator mode and external field strength. This set of tables constitutes a fingerprint of the fluid condition. By matching the fingerprint against a set of fingerprints taken under known conditions, the condition of the fluid is determined. Changes in the fluid's dielectric constant caused by oxidation or the presence of water, changes in the concentration and size of conducting particles from bearing wear, and changes in viscosity all affect the fingerprint; and thus, can be monitored in real time. In a variation of the invention, a lumped-circuit resonator printed on a microwave circuit board is used as the sensor. In a further variation, a transmission-line resonator printed on a microwave circuit board is used as a sensor. In yet another variation the resonator is a lumped circuit waveguide structure through which the fluid flows. In still another variation, time domain reflectometry is used in a transmission line having one end immersed in the fluid.