NOVELTY - The machine has distribution element (41) for distributing the hot air in inside of dryer portion (10). The input cut off level switch (16c) is used to block the input of sludge in dryer portion, when the sludge amount is large. A controlling element (50) is used to control the emission quantity of dried sludge. A removing unit (70) is connected to rear end of dryer portion, so as to remove the foreign substance included in hot air. A discharge unit (74) is used to collect the foreign substance separated from waste hot air and to eject the collected substance to transport unit (60).    USE - Integrated packed-bed sludge drying machine for drying organic sludge used as fertilizer, heat power plant fuel and cement kiln auxiliary fuel.    ADVANTAGE - Since the foreign substance removing unit is installed in the rear end of dryer portion, the foreign substance included in the hot air can be removed easily. Hence the contamination of the waste hot air ejected to the outside can be prevented effectively. The sludge can be recycled easily and effectively. The level switch is installed at the upper portion of dryer portion, to control the sludge input amount, so that the sludge amount dried in the dryer portion is regularly maintained. The oscillating element is provided in the lower portion of the dryer unit, so that the mobility of sludge in the inside of dryer portion is improved, while improving the drying efficiency of sludge. The optimal temperature of the hot air can be maintained. The consumption of the fossil energy including coal or petroleum is reduced. The warm water and waste heat can be utilized to dry the sludge. The sludge can be dried at low temperature. The drying cost of sludge can be reduced. The hot air is injected in the upper side and lower side of the dryer portion and the hot air of the same temperature is provided to dry the sludge, so that the loss of dry heat source is minimized. High conversion power and higher calorific power of the dry sludge are maintained. The time for passing the sludge into the inside of drying machine can be reduced. The thermal efficiency of the drying machine can be improved, by changing the inflow position of hot air. The emission quantity of the dry sludge can be controlled easily by using the rotary valve. The quality of the dry sludge can be improved. The separation of the foreign substance from waste hot air can be facilitated.    DETAILED DESCRIPTION - The hot air implantation portion (20) is provided in one of the sides of dryer portion, so as to inject the hot air into the dryer portion. The exhaustion initiation level switch (16a) is operated, so as to exhaust the sludge. The hot air exhausting unit (30) is used to eject the hot air to the outside. The slide gate (14) is united with the exhaustion initiation level switch.    DESCRIPTION OF DRAWING(S) - The drawing shows a front view of the sludge drying machine.    Dryer portion (10)    Slide gate (14)    Exhaustion initiation level switch (16a)    Input cut off level switch (16c)    Hot air implantation portion (20)    Hot air exhausting unit (30)    Distribution element (41)    Controlling element (50)    Transport unit (60)    Foreign substance removing unit (70)    Debris discharge unit (74)