Pretreatment device for graded collection of potatoes

The pretreatment device comprises a supporting rack and a cleaning tank which is fixedly installed on the supporting rack and provided with an upward opening, the cleaning tank comprises a horizontal tank body and an inclined tank body, and a feeding guide plate and a discharging guide plate are arranged at the two ends of the cleaning tank; a conveying mechanism is arranged in the cleaning tank and is driven by a driving mechanism to operate; the pretreatment device further comprises a spraying mechanism and an air injection mechanism, the spraying mechanism comprises a spraying main body, a circulating pump, a circulating water filter tank and a first connecting pipe assembly, a circulating opening is formed in one side of the bottom of the horizontal tank body, and the spraying main body is arranged at the top of the horizontal tank body; the air injection mechanism comprises an air injection main body, a second connecting pipe assembly and an air blower, and the air injection main body is arranged at the