US Patent 7793689 Multilayer heat tracing insulation device and method

A heat tracing device has one or more heating elements positioned adjacent to a heatable surface, an aerogel high temperature insulation layer adjacent to the one or more heating elements, a low temperature insulation layer adjacent to the aerogel high temperature insulation layer and a locking mechanism effective to fix the position of the low temperature insulation layer to the aerogel high temperature insulation layer.