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:
Jul. 06, 2004
Filed:
Nov. 03, 2003
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
A liquid filter ( ) housing an annular filter element ( ) has an annular space or inlet chamber ( ) between the filter element and the housing and viewable through the housing 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 level of liquid in the inlet chamber the greater the pressure drop across the filter element. A change interval plugging indicator ( ), preferably part of the filter element, is provided by a gas trap and pressure responsive release mechanism ( ) trapping gas in the upper section ( ) of the inlet chamber until a designated release pressure is reached, corresponding to a desired terminal pressure, to prevent premature plugging indication otherwise indicated by rising liquid level in the inlet chamber. Accurate and reliable calibration is enabled by separating the filtration function and the plugging indication function.