Abstract: There are some problems commonly existed in the dry ice expanded tobacco(DIET) system,such as unable to control the opening/closing speed of impregnator lid and associated strong mechanical shock,and unable to accurately control the amount of liquid CO₂ applied into the impregnator.Therefore,a speed control system and a loading(weight,5000 kg) control system were added to the Jinan Model C 800 kg/h DIET system.The speed control system accurately controlled the opening/closing speed of the impregnator lid to reduce the dynamic impact.Weighing cells were installed at the base of the impregnator to accurately monitor the input volume of liquid CO₂ along with the liquid level control.The comparative test results of practical application showed that the average time of lid opening/closing reduced by 10 seconds,the variation of CO₂ volume was about ±10 kg.The improvement raised the stability of tobacco dipping,eliminated the negative influence caused by temperature error,shortened circulation time,and reduced mechanical shock.