Abstract: Aluminum silicate or mixtures of aluminum silicate and silica are utilized as insulating materials with low thermal conductivities. The aluminum silicate or the mixtures are dried, compressed, placed in a gas-tight envelope, evacuated and sealed. The resultant rigid, board-like panel can be used directly as thermal insulation or it can be used in conjunction with other insulating materials, for example, polyurethane foam.

Abstract: A method for insulating thermal devices with a composite insulation system including an evacuated powder and a plastic foam. A formed plastic part divides the insulation space between the outer case and inner liner into sectors. Some sectors are filled with a finely divided powder, the remaining sectors are filled with foam, for example, polyurethane. A vacuum is applied to the powder filled sectors while the foam is expanding and curing.