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:
Aug. 26, 2003
Filed:
Aug. 22, 2001
Zemin Jiang, Cookeville, TN (US);
Ted Franklin Prater, Sparta, TN (US);
John W. Clevenger, Jr., Antioch, TN (US);
John Scheuren, Brentwood, TN (US);
Fleetguard, Inc., Nashville, TN (US);
Abstract
A liquid filter ( ) housing an annular filter element ( ) has an annular space ( ) between the filter element and the housing and viewable through the housing such that an operator can see the level of liquid in the annular space as an indication of when to replace the filter element, the higher the level of liquid in the annular space the greater the pressure drop across the filter element. The rise in liquid level in the annular space is delayed for applications where the filter element is otherwise changed prematurely and has a longer life than otherwise indicated by the rising liquid level in the annular space. The delay is provided by a liquid and vapor impermeable sleeve ( ) trapping vapor. In a further aspect, the sleeve is provided with apertures ( ) filled by liquid-soluble buttons ( ) providing filter element change interval indication, including advance sequential indication.