The device by the human operator launches, such as through the cone-shaped gear reducer drive, direct drive valve stem up and down movement of the valve gate.
本装置由人力操作手轮，通过锥形齿轮等减速传动，直接驱动阀门阀杆上下移动，启闭阀门。
3
The features and application scope of different alternating and direct current motors used as the drive device of gear pump were compared.