OPERATING METHOD OF DRY DISTILLER

PURPOSE:To make improvement in treating capacity and to save fuel by judging the end point of dry distillation by detection of the current value of a motor driven fan at the time of putting a material to be dry distilled into a dry distillation still and dry distillating this material by heating. CONSTITUTION:The material which is to be dry distilled and contains grinding oil is put into a dry distillate housing vessel 30 in the dry distillation still 10 and the distillation still is hermetically closed by a cap 26. Gaseous nitrogen is introduced from a tank 54 via a valve 53 into the distillation still to maintain a nonoxidative atmosphere in the dry distillator 10. A motor 27 is then drive to turn the motor driven fan 28 in the dry distillation still 10 and an oil burner 18 is burned to heat the inside of the dry distillation still 10 by which the material to be dry distillation is dry distillated. The cutting oil contained in the material to be dry distillated evaporates and the load of the motor driven fan 28 increases when the temp. of this material rises. The gas of the high molecular weight is no longer generated and the load of the motor driven fan 28 decreases upon ending of the dry distillation. The time when the current value of the motor driven fan 28 decreases to the initial value of the dry distillation is judged to be the end point of the dry distillation.