Roller vacuum drying machine

The invention discloses a roller vacuum drying machine. The roller vacuum drying machine comprises a roller drying bin, a roller path, a gear ring, a three-way device, an elbow device, a discharging valve, a vacuum unit, riding wheels, a support and a driving device, wherein the roller drying bin comprises a heat preservation bin and a drying bin; the drying bin comprises a roller, a metal cover,a heating pipe, a heat conduction pipe and a spiral blade; to-be-dried materials out of the roller drying bin enter the interior of the drying bin through the discharging valve on the feeding port ofa three-way pipe of the three-way device on a bin inlet of the drying bin of the roller drying bin; the heat-conducting medium conducts heat conduction and heating in the metal cover and the heating pipe, the conduction speed of heat energy is increased, and the vacuum unit pumps and exhausts air in the drying bin and moisture generated during material drying; the collision contact rate with materials and the heat conducti