GB457478A - Improvements in muffle furnaces - Google Patents

Abstract

457,478. Metal - heating furnaces. SOUTH METROPOLITAN GAS CO., CHANDLER, D., and SKINNER, A. J., 709, Old Kent Road, London. May 29, 1935, No. 15683. [Class 51 (ii)] In a bell-type metal-heating furnace of the kind comprising separable bell and hearth portions 26, 31, and an inner charge-containing muffle B which is externally heated by the gases from burners C, an intermediate bell 25, having an opening 27 at the top and extending downwardly into the sand seal 32 between the bell and hearth portions 26, 31, is provided to cause the gases to pass first up an inner chamber D and then down an outer chamber E. As shown, the gases may be given a third pass by the provision in the wall of the bell 26, of a flue 33 leading to the stack outlet 34. The heating chambers D, E are fitted with vertical baffle plates 28, 29 carried on the muffle B and the bell 25 respectively. In the form shown, the base 31 is stationary and the bell 26 is fitted with eyes 38 by which it may be raised and lowered ; to provide for the insertion and removal of the charge-box A, the muffle B is formed of a bell-like upper portion 21 and a base 22 connected by a sand seal 24. In a modified construction, having a fixed bell 26 and a vertically movable base portion 31, both sets of baffle plates 28, 29 are carried on the intermediate bell 25.