RDVD consists of two concentric drums with inner drum rotating inside stationery outer drum. The inner drum which rotates at 1 to 2 rpm has a hollow shaft which serves as inlet for material and vacuum. Outer drum remains stationery and has steam inlet and condensate outlet.
The doors are handled using chain pulley block system.
RDVDs find application mostly in herbal industries wherein material to be dried is temperature sensitive and sticky in nature.