A method of insulating a heated surface comprising enveloping the surface by a first layer of a heat insulating material having a high thermal resistivity such as Mineral Wool, and enveloping the first layer by a second layer of a material having a lower thermal resistivity, such as Polyurethane....http://www.google.fr/patents/US5934338?utm_source=gb-gplus-shareBrevet US5934338 - Heat insulating covering and method
