The invention discloses a quality guarantee unit. The quality guarantee unit is characterized in that the quality guarantee unit comprises a barrel body. A material inlet and a material outlet are arranged on the barrel body. A rotor is matched inside the barrel body. The rotor is characterized in that the rotor comprises a front rotor shaft, a rear rotor shaft, ribbon advancing blades and bulk discharging end blades, wherein the ribbon advancing blades are sequentially arranged on the front rotor shaft along the axial direction, and the bulk discharging end blades are sequentially arranged on the rear rotor shaft along the axial direction. The front rotor shaft and the rear rotor shaft are respectively connected with a generator set I and a generator II. Speed difference is formed between the generator set I and the generator II. The rotate speed of the front rotor shaft is much less than the rotate speed of the rear rotor shaft. The quality guarantee unit is simple in structure, stable in operation and convenient in field installation and can guarantee the delivered material to be even in size.