Patent ID: 7219442
Filing Date: 2007-05-22
Classification: F26B

Abstract:
1. A method of contact drying in a device having a heated cylinder in which a rotatable agitator has a blade which is disposed adjacent to a cylindrical inner side surface of the heated cylinder, said method comprising the steps of introducing a moist material which is to be dried into the heated cylinder, rotating the agitator relative to the heated cylinder to promote comminution and homogenization of the moist material, heating the moist material in the heated cylinder during rotation of the agitator, measuring the temperature of the moist material in the heated cylinder during rotation of the agitator and heating of the moist material, reducing the pressure in the heated cylinder to a pressure below atmospheric pressure during rotation of the agitator and heating of the moist material in the heated cylinder, said step of reducing the pressure in the heated cylinder includes reducing the pressure to a pressure below a vapor pressure of a solvent in the moist material during heating of the moist material in the heated cylinder, and preventing recondensation of solvent in the moist material by not allowing the temperature of the moist material to decrease by more than 5° C. during the heating of the moist material in the heated cylinder.