Thermal protection or dissipation screen

Claim 1

A thermal dissipation screen applied to the external surface of a substrate to protect said substrate from high temperatures, said screen comprising a bottom layer for directly covering the exterior surface of the substrate to be protected, said bottom layer comprising a polymeric material optionally reinforced with fibrous material; a supple hydrator-overheater layer overlaying said bottom layer, said hydrator-overheater layer comprising a refractory fibrous network, a pulverulent inorganic material capable of absorbing and retaining a liquid to produce a paste or a gel of a high thixotropic efficiency, and a liquid having a vaporization temperature at the pressure of the environment equal to that corresponding to the desired protection temperature of the substrate; and a flexible upper and exterior layer covering said hydrator-overheater layer, said flexible upper layer comprising a polymeric material which becomes porous at temperatures higher than said vaporization temperature, said upper and exterior layer constituting means permitting said liquid to vaporize at the pressure of the environment.