Blowing and drying section air system of belt type roasting machine

The utility model relates to a blast drying section air system of a belt type roasting machine and a control method, and the blast drying section air system comprises the belt type roasting machine and a blast drying fan, and is characterized by also comprising a cold section air return pipeline, a blast drying section waste gas pipeline, a blast drying section end part upper cover, a blast drying section end part air box, a blast drying section dust removal pipeline and an air mixing device, a first cold section air return pipeline of the belt type roasting machine is connected with a blowing-drying section waste gas pipeline through a regulating valve I, a blowing-drying section end upper cover is connected with a blowing-drying section dust removal pipeline through a regulating valve II, a blowing-drying section end air box is connected with the blowing-drying section dust removal pipeline through a regulating valve III, and the first cold section air return pipeline is connected with the blowing-drying se