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.

Date of Patent:
Jul. 25, 1995

Filed:

Dec. 30, 1993
Applicant:
Inventors:

Paul J Voelker, Fremont, CA (US);

Joe D Hedges, Portola Valley, CA (US);

Assignee:

Other;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ; G01N / ;
U.S. Cl.
CPC ...
73 5305 ; 2041531 ; 204409 ; 324663 ; 324698 ; 324449 ; 422 8201 ; 422 8202 ;
Abstract

A method and apparatus for determining the quality of a lubricant by its solvating effect on an insoluble (resin) matrix to which charged groups have been covalently bound. The solvating effects are measured electronically as a variation in conductivity or capacitance of the resin matrix with respect to temperature. The apparatus includes a metal mesh housing containing e.g. milligram amounts of charged resin beads. A metal probe is fitted in the containing mesh and makes contact only with the resin beads. The entire device is immersed in the lubricant and the electrical conductivity or capacitance is measured from the probe to the mesh through the resin beads. Lubricant degradation is measured as e.g. a decrease in electrical conductivity through the resin beads with respect to an increase in the lubricant's solvent polarity.


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