Normalizing preheating box

A normalizing preheating box comprises a preheating box body, a rail inlet and a rail outlet are distributed in the two sides of the preheating box body, a rail is fixed in the preheating box body, the two ends of the rail extend outwards and reach the outside after passing through the rail inlet and the rail outlet, the top of the preheating box body is communicated with a hot air pipeline, and an air outlet is formed in the top of the preheating box body. The upper end of the air outlet is hinged to the edge of the air door. Compared with the prior art, the air door has the technical effects that the opening degree of the air door is reduced through gravity, the opening degree is increased through pressure in the preheating box, and the opening degree of the air door can be automatically adjusted. 一种正火预热箱，包括预热箱，预热箱的两侧分布设有轨道进口、轨道出口，预热箱内固定轨道，轨道的两个端部均向外延延伸、通过轨道进口、轨道出口后到达外界，预热箱的顶部连通热风管道，预热箱的顶部设有出风口，出风口的上端部铰接风门的边缘部。相对于现有技术，本实用新型的技术效果为，本实用新型的风门通过重力实现开合度变小，通过预热箱内的压力实现开合度变大，能够实现风门的开合度可以自动调整。