FURNACE FOR THERMAL AND CHEMICAL TREATMENT OF METALWARE IN CONTROLLED ATMOSPHERE AND METHOD OF ITS HEATING Russian patent published in 2001 - IPC

FIELD: metallurgy, mechanical engineering. SUBSTANCE: furnace for thermal and chemical treatment of metal-ware in controlled atmosphere and method of its heating can be utilized in production of various metal-ware, for instance, bolts, nuts, expansion anchors. Proposed furnace has zones of heating, precise heating and soaking. Each two adjacent radiation tubes in zone of precise heating are connected in pairs and in series by heat insulated goose-neck pipes brought outside limits of furnace to form common multibranch heater whose first branch is fitted on side of loading of metalware with gas burning unit and whose last branch is equipped with fume branch pipe linked to united outside recuperator. All radiation tubes in zones of heating and precise heating are mounted in horizontal planes parallel to transportation conveyer and in vertical plane in zone of soaking across exit from conveyer. Air collectors of upper and lower rows of radiation tubes are coaxially built in fume conduits and form outer recuperators united in rows and linked by flanges to fume branch pipe of radiation tubes with adjustable clearances. Method of heating of furnace lies in following: combustion products of each pair of adjacent radiation tubes of zone of precise heating are fed in sequence from first heaters into second heaters which are outside of limits of working space of furnace and its insulation and are removed from second heaters into united outside recuperators to ensure that pressure in points of their connection to fume branch pipes of radiation tubes is equal to atmospheric values of environment. EFFECT: improved quality of thermal and chemical treatment of metalware, raised efficiency of furnace and prolonged service life of radiation tubes. 4 cl, 3 dwg _