Method and apparatus for effecting convective heat transfer in a cylindrical, industrial heat treat furnace

摘要

A low cost, improved convective heat transfer furnace is disclosed which includes a cylindrical casing to which is attached blanket insulation and the casing is closed at its ends to define a closed end cylindrical furnace enclosure. An annular fan face plate is positioned within the enclosure to define a pressure zone on one side and a work zone on the other side. A paddle wheel fan in the work zone develops a large mass of circumferentially swirling wind which is initially formed as a stationary swirling mass without an axial force component but which under pressure travels axially in the form of a swirling annulus through the non-orificing annular space. The under pressure zone established by the central opening in the fan face plate causes the swirling wind annulus in the work zone to expand radially inwardly and uniformly impinge the complete surface of the work in an effective heat transfer manner before being recirculated back to the pressure zone.