Used Drum Dryers generally consist of one or more hollow metal cylindrical rolls or drums that are mounted to rotate on horizontal axes at a variable speed. Often the drum is heated via steam or hot water. The product is spread onto the surface of the used drum dryer and is dried by the heat transfered throught the metal thickness from the heat inside the drum. A knife is often fitted to the drum to scrape of the the thin layer of dired material from the drum surface. Manufacturers of used Drum Dryers include Simon Dyers, Buflovak and Gouda.