GB881984A - Furnace - Google Patents

Abstract

881,984. Metal heating furnaces; cooling furnace charges. BUKATA, S. May 6, 1960, No. 16167/60. Class 51 (2). [Also in Group XI] In an electrically heated brazing furnace including removable top and bottom sections 22, 24 and a pair of envelope sheets 32, 34 held apart by a channelled closure member 42 grooved at 64, 66 in its faces juxtaposed to the sheets, the grooves contain gaskets 68, 70 and channelled members 40, 42, 44 form an outer casing through which cooling fluid passes. The envelope sheets 32, 34 are corrugated to allow for thermal expansion and one of these (member 32, Fig. 6, not shown), may be of " concertina " form so that the heating space defined between the sheets and a perforated spacer of suitable size may accommodate articles, such as laminated structures, of varying size. The heating space is evacuated through tube 82 and may be provided with an inert gas atmosphere of, for example, helium or argon through pipe 86. Heat equalizing elements such as graphite blocks 90 may be provided. Various modifications are described in which one of the graphite blocks is disposed inside the heating space or between the lower envelope sheet and a third like corrugated sheet. In such arrangements the block additionally serves to support the charge and the furnace cover is removed hydraulically. A variety of casings for furnace assemblies mounted on wheels, rollers and the like are described (see Figs. 12, 14, not shown). In these larger arrangements provision is made for the introduction of cooling gas and liquid from tanks 324, 326, Fig. 11, into the heating element space 232, 234, so that heated structures may be rapidly cooled to room or subzero temperatures. Thus coolant gas is admitted into the housing from tank 326 by opening valves 329, 336 and 344. After the structure 212 has been cooled by gas entering spaces 232, 234 liquid coolant from tank 324 may be introduced by opening valve 328, and passing it through pipes 340, 342, 348 and 350. Expansion of the liquid as it emerges from nozzles in the ends of the said pipes causes it to supercool the structure. Thus it is possible to heat and cool the structure 212 several times if necessary without removing it from the furnace.