To improve the quality of a dried product and the operation efficiency of a sludge drying apparatus by stabilizing the water content of sludge after being dried.
Sludge is supplied into a drum 1 through a screw feeder 3, agitated by a screw 2, and dried by being contacted with an inner wall 1b surface. A volatile gas, mainly containing water vapor, generated from the sludge is sucked by a blower 5 through a dust removing filter 11 and introduced into a flue 8 in the neighbourhood of a burner 7. The volatile gas, after being burned in the flame of the burner 7 and deodorized, is discharged into the air through the flue 8 and a stack 9. The humidity of exhaust gas to be discharged is measured by a humidity sensor 10 set in the stack 9. The amount of water vapor generated from the sludge is reduced gradually with the progress of drying. By obtaining the relationship between the water content of the sludge and the humidity of the exhaust gas in advance, the progress of sludge drying can be known from the measured value of the humidity.
KUSANAGI HIROAKI
ISHIKAWA TAKETOSHI
Next Patent: METHOD AND APPARATUS FOR DRYING SLUDGE