GB570677A - Improvements in ovens and kilns - Google Patents

Abstract

570,677. Ovens and kilns. CAMPBELL, A. J. Sept. 9, 1943, No. 14779. [Class 51 (ii)] In an oven or kiln 'of the kind comprising a heat insulating structure usually of circular form confining an annular or circular chamber enclosing a base on which goods are supported and divided into zones in each of which the goods are progressively heated and cooled, relative rotation of the structure and base being effected so that each part of the insulating structure is alternately heated and allowed to cool, the heating elements and the rotation of the heat insulating structure or base are controlled so as to maintain a heating cycle which moves around the structure and which provides a hottest section, .one or more cooling sections, one or more preheating sections and one or more relatively cold sections, the heat insulating structure rotating at each step or in a given period of time in the same direction but through a greater distance than the heating cycle or the goods carrying base rotating in the opposite direction to that taken by the heating cycle. Figs. 1 and 2 show an annular tunnel oven or kiln consisting of a heat insulating structure 21, 22 rotated continuously or at intervals about the fixed goods supporting base 10 which is provided with vertical partitions 11 and supports 16 for the goods 17 with which may be associated electric resistance heaters. The walls are provided with removable sections 27, 28 for loading and unloading. Circulation of the atmosphere between the partitions 11 may be effected, as shown in Fig. 4, by a fan 40 associated with air circulation ducts 43 in the base 10.