Heat insulating assembly

Claim 1

In combination with a shell-like casing having a plurality of rectangular planar walls joined together at the parallel corners thereof, a one-piece plaque of heat insulating material sized to provide an interior lining for at least three contiguous ones of said planar walls, said insulation comprising a continuous onepiece thick layer of randomly arranged glass fibers initially connected together at points of crossover by thermosetting binder material to form a planar mat of uniform thickness and density, said planar plaque being divided into a plurality of panels corresponding in size to a respective one of said planar walls and connected together by inwardly facing V-shaped channels positioned closely parallel to the parallel corners of said casing and extending from edge to edge of said one-piece plaque, and the glass fibers of said V-shaped channels being permanently held interlocked together in more densely compressed condition by said binder material being more completely polymerized than the binder material in the less densely compacted areas of said planar layer and effective resiliently to resist folding said panels toward one anothEr about hinge axes medially of said Vshaped channels, whereby said strip of insulation, upon being folded and installed against the interior walls of said casing, tends to expand to hold the panels thereof pressed flush against the interior surfaces of said casing walls.