Abstract: A pit cover for retaining heat in an open top, ring-shaped, carbon anode baking furnace comprises an insulating cement cast into the form of the cover, at least one metal beam embedded in the insulating cement, and a plurality of stainless steel needles interspersed substantially throughout the insulating cement for reinforcement purposes. The insulating cement has a K factor of approximately 2 to 4, a density of approximately 80 to 100 lb./ft..sup.3, a cold crushing strength in the range of 1,000 to 5,000 psi, and a low iron content, preferably, less than 2%.

Abstract: This invention relates to a device for cleaning opposed walls of a furnace pit. The device comprises a plurality of rotating screw-type cutters for removing built-up deposits upon the opposed walls of the furnace pit, a plurality of linkage arms for carrying the plurality of rotating screw-type cutters, a plurality of air motors for independently adjusting the speed of each half of the plurality of rotating screw-type cutters along each opposed wall of the furnace pit, and universal joints for allowing floating adjustment of each of the plurality of rotating screw-type cutters against each opposed wall of the furnace pit.