摘要 |
A passive insulating system can provide highly effective protection in the presence of transient high temperatures. The system comprises, for example, a porous body forming a multiplicity of fine cells with a material having low thermal conductivity, a thermally absorptive liquid, providing an endothermic reaction in the presence of a catalyst, and a finely divided catalyst for the reaction uniformly distributed in the porous body. In preferred systems, the thermally absorptive liquid is para-hydrogen, the catalyst is granulated ferric oxide, and the liquid para-hydrogen changes to gaseous para-hydrogen, and from para-hydrogen to ortho-hydrogen in the presence of the ferric oxide catalyst, absorbing heat by its heat of vaporization and endothermic catalytic reaction and reducing heat transfer through the porous body.
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