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. 08, 2002
Filed:
Feb. 12, 2002
Maninder S. Sehmbey, Hoffman Estates, IL (US);
James P. Chen, Schaumburg, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A heat pipe and method that utilizes a multi-layered shape memory alloy (SMA) as the wick structure. Each layer has a different transformation temperature. The inner layer of the SMA begins contracting first when heat is applied along the surface of the heat pipe. The contraction reduces the effective capillary radius r of the wick, thereby maintaining or increasing the capillary pumping pressure and thus the ability to remove heat. As the temperature of the heat pipe continues to rise, the outer layer begins contracting to reduce the capillary radius further. As a result, the local pumping pressure is maintained or even increased to accommodate higher local heat flux and remove the heat to prevent “dry-out.”