The trolley type hot air circulation drying furnace is mainly used for uniform temperature drying of various processed parts. The electric furnace structure consists of a furnace body, a trolley, a heating device, a control system, and other parts. The frame of the furnace shell is made of welded steel sections, and both the inner and outer walls are made of cold-rolled steel plates with a low coefficient of thermal deformation. The inner lining is made of aluminum silicate refractory fiber needle punched cotton as insulation and thermal insulation material to reduce the temperature rise of the furnace wall. The furnace door and shell are also made of welded steel frame, the outer wall is also made of cold-rolled steel plate, and the inner lining is made of aluminum silicate refractory fiber needle punched cotton as insulation and thermal insulation material. The small car is welded with steel sections and equipped with wheels at the bottom for flexible movement. The entire car can be pushed into the furnace body. Rubber asbestos packing is embedded around the furnace mouth, and after the furnace door is closed, it is tightly attached to the rubber asbestos packing at the furnace mouth to ensure no heat dissipation. The heating element adopts strip electric heating elements, which are arranged on both sides of the furnace and made of 0Cr2L5 alloy, with a long service life. To ensure the stability and uniformity of the furnace, the electric furnace is equipped with a ventilation fan device and an air guide system. The ventilation fan device is placed on the top of the furnace body, and the fan is made of 1Cr18Ni9Ti heat-resistant steel and has centrifugal blades. The air guide system consists of an air guide plate and a wind deflector. The air guide plate is installed at the top of the furnace and has an air guide groove on it. When the fan is turned on, the wind is thrown out of the fan, evenly blown onto the heating elements on both sides of the furnace through the air duct, blown into the furnace through the air duct at the bottom of the wind deflector, and then sucked into the fan through the air duct at the bottom of the fan before being thrown out. This cycle repeats, bringing the heat generated by the heater into the furnace and evenly heating the workpiece. The temperature control system adopts PID zero crossing trigger thyristor and intelligent meter temperature control. Additionally, Shanghai Dahua Instrument Factory adopts a multi-point automatic recorder to record temperature and dual control of over temperature alarm, ensuring that the workpiece does not exceed the temperature limit. The mechanical transmission parts of the electric furnace adopt chain control, which automatically cuts off the power supply of the ventilation fan device and heating elements after the furnace door is opened. After the furnace door is closed in place, the power supply of the ventilation fan device and heating element can be connected to prevent malfunctions and accidents caused by misoperation.
