The device has a hot air circulation passages and stir fans, so hot air furnace in the role of spoiler directed cycle, the furnace is equipped with activity on both sides of the door, it wall to form an air circulation channel, top of the furnace is set to have a wind capacity of axial fan and diversion structures, constitute hot air circulation system. Car-circulating hot air drying furnace is mainly used for a variety of workpieces average temperature drying furnace structure consists of furnace, car, heating equipment, control systems and other components. Furnace shell frame using steel is welded inside and outside walls are made of high-quality cold-rolled steel production, low coefficient of thermal deformation, lined with cotton for acupuncture aluminosilicate refractory fiber insulation and insulation materials, reducing furnace wall temperature. Door furnace shell also make use of steel welded framework, also produced by the outer wall of cold-rolled steel, aluminosilicate refractory lining is also used for acupuncture cotton fiber insulation and insulation materials. There welded steel trolley, go round the bottom with walking flexible whole car can be pushed into the furnace. Mouth around embedded rubber asbestos packing, after the door closed and mouth snapping rubber asbestos packing, ensure that no heat dissipation. Heating elements ribbon heating elements, are arranged on both sides of the chamber, made of 0Cr25AL5 alloy, long service life. To ensure uniformity of furnace stable, furnace has a fan unit and ventilation system, device placed in the top of the furnace fan, fan with heat-resistant steel made 1Cr18Ni9Ti centrifugal fan. Wind systems and wind by the wind deflector panels, wind deflector mounted on the top chamber, there are guide duct. After turning on the fan, the wind from the fan thrown, blown by the wind on a uniform groove furnace heating elements on both sides of the lower guide plate through the windshield blown air furnace, and then from the lower part of the fan outlet guide sucked into the fan, ?????? again thrown, and so forth cycle, the heat generated by the heater into the furnace, the workpiece is heated evenly. PID temperature control system uses zero trigger SCR, intelligent temperature control table. Another use of multi-point Factory Shanghai Dahua loggers record temperature and over-temperature alarm dual controls to ensure that the workpiece does not over-temperature. Each part of the furnace uses mechanical transmission chain of control, automatically cut off the power supply fan unit and heating element after that the door is open. After the door closed in place, in order to power the fan unit and a heating element to prevent misuse and failure and accidents