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:
Jan. 16, 2001
Filed:
Sep. 07, 1999
Jason Thomas Stoll, Rochester, MN (US);
Maurice Francis Holahan, Lake City, MN (US);
Dale Lidberg, Alexandria, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A fan check valve is formed from plastic film having an outer edge and a central region. The valve also has a number of slits that define flaps in the film. The flaps are symmetrically arrayed in a spiral-like pattern between the central region and the outer edge. The valve mounts to the outer surface of a tube axial fan. Under normal operating conditions, the fan moves a helical flow of air in a generally axial direction toward through the valve. The flaps are blown open and align with the oncoming flow at low angles of attack to minimize dynamic losses. The flaps are in the closed position and lie flush on the outer surface of the exhaust plate mounted on the fan at all other times to prevent airflow back through the fan in the opposite direction once the fan has failed.