The annealing of glass jars is to reduce the residual stress of the glass to the allowable value. Annealing is usually carried out in a mesh belt type continuous annealing furnace, and the annealing temperature is limited to about 550-600 °C. The mesh belt annealing furnace adopts forced air circulation heating, which makes the temperature distribution of the cross section of the furnace uniform and forms an air curtain, which restricts the longitudinal airflow movement and ensures the uniform and stable temperature of each belt in the furnace.