If at extremely low differential, it has better stability and accuracy and can be adjusted accurately within the range of 1-35r/min. Once the machine needs to be cleaned because being blocked, the scroll stowing tool can be driven separately for discharging, which reduces the workload and the maintenance cost greatly. Other type of differential speed gears can not do this. In normal operational process, the scroll stowing tool rotates constantly. If the scroll stowing tool gets increasing load, the machine will makes it rotate quickly to speed up stowing and prevent from being blocked automatically.