GB277379A - Improved process and apparatus for accelerating the cooling in electrically heated bright heating furnaces - Google Patents

Abstract

277,379. Akt.-Ges. Brown, Boveri, et Cie. Sept. 10, 1926, [Convention date]. Casings and walls; cooling; charges, cooling; covers; gases, supplying. - In an electricallyheated bright annealing furnace in which the charge is cooled within the furnace, a depending bell g of heat-conducting material is secured to the counterweighted cover d, which, as shown in Fig. 2, is raised during the cooling period to expose, without breaking the furnace seal, more or less of the surface g according to the cooling time required. The bell g extends into a liquid seal f, formed between the sheet-iron furnace casing c and an outer shell e and carries an annular float h which, when liquid is supplied to the space f, raises the cover d while still maintaining the seal. Inert gas is supplied and withdrawn through pipes o, q respectively, a pressureregulator p being arranged in the pipe o to prevent the sealing-liquid from being sucked into the furnace when the cover d is raised. The liquid enters the seal at i and escapes through either k or m, the latter outlet being preferably utilized to produce a circulation of the liquid during both the heating and cooling periods, the cover d being in the former case secured in its closed position. The seal f may be dispensed with and the bell g arranged as a sheath slidable on the casing c. In a modification, the outer shell e is formed of non-conducting material, thus permitting the use of a thinner furnace wall b. Fig. 4 shows a further construction in which the bell extends downwardly into a seal f below the furnace, the upper half t being formed of non-conducting and the lower half g of material.