US Patent 8453393 Encapsulated and vented particulate thermal insulation

An article includes a piece of encapsulated insulation including an envelope having at least two vents therethrough, a particulate insulation within the envelope, and a porous filter overlying each vent of the envelope. The porous filter has a mesh size no larger that the minimum size of the particles. The article may further include a structure having a structure surface, and the piece of encapsulated insulation overlies and covers at least a portion of the structure surface.