Abstract: A refractory sheathing (1) of incombustible, compressed, flat insulating bodies (8) made of mineral or ceramic fiber for thermally insulating pipes (10) in preheating furnaces fired from below in the steel industry is described. The insulating bodies (8) have an inner and, if desired, also an outer arc-shaped profile, they enclose the pipes (10) to be insulated totally or almost totally in circumferential direction, and they are secured at the pipe in close mutual abutment by at least two retainers which engage the ends of a plurality of adjacent insulating bodies (8) forming a stack of insulating bodies. The risk of separating from the pipe during the constant vibrations of the same is reduced and the space requirement for installation at the building site as well as the cost of mounting involved are scaled down by the line-up of a plurality of insulating bodies (8) on a plurality of spaced apart rods (11) to form a highly compressed insulating body stack.

Abstract: A refractory sheathing made from insulating shapes for vertical support members, in particular riser pipes, in heat-treating furnaces, e.g., pusher furnaces, comprises an inner layer made from a refractory, fibrous, insulating material, or an appropriately shaped article, surrounding the support members and an outer layer of positively interengaging, refractory, shell-shaped shapes of, for instance, the same height throughout, surrounding said inner layer. To avoid a large number of different shapes having to be correspondingly expensively manufactured in different moulds to match support members of different dimensions and double pipes, it is proposed that only equal-leg angle pieces of different leg lengths, in particular two different angle pieces, and straight intermediate pieces of different widths, in particular only two or three widths, be provided as shapes. All shapes have grooves on two contiguous sides at right angles and matching tongues on both of the other contiguous sides at right angles.