Tunnel kiln has been widely used in refractory industry because of continuous operation, maximum utilization of flue gas and waste heat, high thermal efficiency and good working conditions. It is suitable for firing various refractory bricks such as high alumina brick, clay brick, silicon brick, magnesia brick, slide board and aluminium-carbon brick. Modern tunnel kilns are developing towards large-scale, lightweight, flat and intelligent trend. [br] [br] 1. Large-scale [br] [br] national industrial policy requires increasing enterprise concentration, enterprise scale, high output of similar products and large market share. Therefore, large-scale kiln can increase the output of single kiln, thereby improving kiln comprehensive efficiency and reducing energy consumption standards. [br] [br] 2. Lightweight [br] [br] refractories are developing towards lightweight. Therefore, building kilns with new insulation refractories can reduce heat storage and heat dissipation, especially kiln trucks, and also reduce the weight of kilns. Alumina hollow spherical brick lining has been widely used in tunnel kilns. Energy-saving infrared reflective coatings are coated on the surface of sintered lining. [br] [br] 3. The creep of the lower part can be reduced by widening the flattening [br] [br] kiln and moderately reducing its height. This requires minimizing the upper and lower temperatures of the pretropical section, adopting a flat ceiling structure, reducing the buoyancy of the hot air flow, and using a high-speed temperature-adjusting burner. [br] [br] 4. Intelligent [br] [br] kiln firing temperature automatic control, double flowmeters + double actuators, precise control of air-air ratio, energy saving 8%~10% year on year, relatively more environmentally friendly. The firing temperature is flexible and optional, and one kiln is more convenient to use, which ensures the traceability of products, the consistency and stability of the same product and different batches. The automatic control of pressure system of [br] [br] kiln is the guarantee of temperature control, so the pressure curve can be automatically realized by frequency conversion adjustment of fan. The kiln car outside the kiln also needs intelligent transfer and central control system. Kiln truck in the kiln outside the transfer, electric trailer walking positioning, the main door lifting, jacking machine automatic entry and exit kiln all chain control, one key operation room to complete. Intelligent management of the whole process of [br] [br] firing products, as long as the product temperature curve, kiln pressure curve and atmosphere curve are input into the industrial computer, click start operation, the control system will automatically complete the whole process of heating, insulation and cooling without manual intervention.