Vacuum dryer is the equipment with the help of which vacuum drying is carried out. In the pharmaceutical industry vacuum dryer is known by a common name called vacuum oven. Vacuum dryers are sometimes made up of cast iron, but most now are made of stainless steel , so that they can bear the high vacuum pressure without any kind of deformation. The oven is divided into hollow trays which increases the surface area for heat conduction. http://www.gj-dryingequipment.com/vacuum-dryer/