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:
Nov. 04, 2003
Filed:
Apr. 04, 2002
Ted Franklin Prater, Sparta, TN (US);
Zemin Jiang, Cookeville, TN (US);
John Scheuren, Brentwood, TN (US);
John W. Clevenger, Jr., Antioch, TN (US);
Barry M. Verdegan, Stoughton, WI (US);
Fleetguard, Inc., Nashville, TN (US);
Abstract
An annular space or inlet chamber between the filter element and housing of a liquid filter is viewable such that an operator can see the level of liquid in the inlet chamber as an indication of when to replace the filter element: the higher the liquid level, the greater the pressure drop across the filter element. A change interval plugging indicator includes a porous outer wrap that traps gas in an upper section of the inlet chamber below a designated release pressure and releases trapped gas upon attainment of the release pressure causing a rapid rise in liquid level within the housing and corresponding to a desired terminal pressure. The indicator prevents premature plugging indication otherwise indicated by a slowly rising liquid in the chamber. Accurate and reliable calibration is enabled by separating the filtering and indicating functions.