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. 31, 1995
Filed:
Dec. 14, 1993
Kuldip Raj, Merrimac, NH (US);
Ronald Moskowitz, Hollis, NH (US);
Ferrofluidics Corporation, Nashua, NH (US);
Abstract
A convection-cooled electromagnetic device, such as a transformer, and methods of cooling that utilize a ferrofluid as a cooling medium. The device's leakage magnetic field, which can be augmented by auxiliary magnets, draws the ferrofluid toward the device. As the fluid approaches the device its temperature rises, resulting in loss of magnetic properties and a decrease in density. The ferrofluid rises as its temperature approaches the Curie point, since the gravitational effect of density reduction begins to overcome the weakening magnetic attraction. Movement of hot ferrofluid is strongly assisted by the attraction exerted by the device on cooler, more intensely magnetic ferrofluid, which displaces the hot ferrofluid. The displaced ferrofluid cools as a result of movement from the heat source and through contact with the walls of the housing. Preferably, the Curie temperature of the ferrofluid is close to or slightly higher than the operating temperature of the device.