Vacuum Drum Dryer (Flaker) is a kind of rotating continuous drying equipment with internal heating conducting-style under vacuum state. Certain thickness of materials film attach to the drum from material liquid vessel under the drum. Heat is transferred to the internal wall of the cylinder through pipes and then to the external wall and to materials film, to evaporate the moisture in materials film so as to dry materials. Dried products are then scraped off by the blade fitted on the surface of the cylinder, fall down to the spiral conveyor under the blade, and are conveyed, collected and packed.
1.High heat efficiency. The principle of heat transfer of the cylinder dryer is heat conduction and the conducting direction keeps identical in the whole operation circle. Except heat loss of end cover and radiation loss, all heat can be used for evaporation of wet materials on the wall the cylinder. The efficiency can reach 70-80%.
2.Large operation elasticity and wide application. Various drying factors of the dryer can be adjusted, such as concentration of feeding liquid/thickness of material film, temperature of heating medium, rotating speed of the drum etc. which can change drying speed of the under dryer. As these factors have no interrelations each other, it brings great convenience to dry operation and makes it applicable to dry various materials and to meet different requirements of production.
3.Short drying period. The drying period of materials is normally 10 to 300 seconds, so it is suitable for heat-sensitive materials. It also can be pressure reducing operated if it is put in vacuum vessel.
4.Fast drying rate. As film of materials coated on the wall of the cylinder is very thin. Normal, thickness is 0.3 to 1.5mm, plus directions of heat and mass transmitting are identical, the evaporation strength on the surface of the film can be 20-70 kg.H2O/m2.h.
5.For the structures of the vacuum drum dryer(flaker) , it has two types : one is single roller , the other is two rollers.
It is suitable for drying liquidrawmaterials or thick liquid in chemical, dyestuff, pharmaceutical, foodstuff, metallurgy and so on industries.