Abstract: For shortening the overturning time of medium draining sieve bend,an automatic overturning version is designed with its drive mechanism made up by a rotary air cylinder and a lift-up air cylinder The selection of the 2 cylinders is made based on related calculation. The sieve bend is now in operation at Yongning Coal Preparation Plant,Shanxi Province. The sieve bend is capable of overturning automatically with a cycle time of approximately 2 minutes.