Description
Class F27B : FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
Subclass 3/04: Hearth-type furnaces, e.g. of reverberatory type (F27B 9/00-F27B 15/00, F27B 21/00 take precedence); Electric arc furnaces of multiple-hearth type; of multiple-chamber type; Combinations of hearth-type furnaces