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:
Oct. 16, 2007
Filed:
Nov. 16, 2004
Bulent Abali, Tenafly, NJ (US);
D. Scott Guthridge, New York, NY (US);
Richard E. Harper, Chapel Hill, NC (US);
Peter A. Manson, Cary, NC (US);
Harry B. Marr, Jr., Atlanta, GA (US);
Bulent Abali, Tenafly, NJ (US);
D. Scott Guthridge, New York, NY (US);
Richard E. Harper, Chapel Hill, NC (US);
Peter A. Manson, Cary, NC (US);
Harry B. Marr, Jr., Atlanta, GA (US);
Lenovo (Singapore) Pte. Ltd., Singapore, SG;
Abstract
A multi-fan apparatus and method incorporates mutual active cancellation of fan noise and/or vibrations. The multi-fan apparatus includes two or more fans circuits, each comprising a fan, a fan speed controller and a separate tachometer, and a fan phase controller. The phase controller is connected to at least one fan speed controller and to each tachometer. Each fan's speed is independently and dynamically maintained at the same set speed by the fan speed controllers using an independent control loops. A noise and/or vibration cancellation phase difference between fans is determined in order to achieve destructive interference of pressure waves and, thus, noise and/or vibration reduction, in pre-determined region of a system incorporating the multi-fan apparatus. The phase controller establishes and maintains this cancellation phase difference between the fans based upon feedback from the tachometers.