Thermally insulating slabs made of refractory fibers for the insulation of furnaces and the like

Claim 1

In a process for thermally insulating a solid surface by lining said surface with a plurality of thermally insulating slabs capable of withstanding normal in use temperatures of at least 1000° C., said slabs each comprising entangled refractory fibers with a major portion of said fibers being substantially parallel to opposed surfaces of said slabs, comprising the steps of providing only one of said surfaces of each said slab with a plurality of open grooves in intersecting relationship, coating said one surface with a refractory cement so as to substantially fill said grooves, disposing said one surface toward the solid surface to be insulated, and maintaining each said slab against the solid surface until at least a partial setting of said cement, whereby the cement occupying said grooves effectively forms a rigid frame for each said slab, which after the setting of the cement prevents contraction of the fibers of each said slab upon crystallization beyond a minimum extent, said slabs thereby being capable of withstanding in use temperatures higher than said normal temperatures without fiber contraction beyond said minimum extent.