Working Principle of Drying Equipment

The need to remove moisture from an object is often encountered in human production and life. Such objects may be solid, liquid or gaseous. In most cases, the moisture contained in the object is water, but sometimes it is other components, such as inorganic acids, organic solvents, and so on. This process of removing moisture from an object is called ‘dehumidification’. The methods of moisture removal are divided into several categories according to the different principles of operation, and drying is one of them.



Generally, the process of removing moisture by thermophysical methods is called ‘drying’. Its characteristic is the use of heating, cooling, depressurisation or other means of energy transfer so that the moisture in the material to produce volatility, condensation, sublimation and other phase change processes and objects separated to achieve the purpose of dehumidification. Do not have this feature of the dehumidification method is usually not included in the category of drying technology.



Drying equipment is a kind of use of thermal energy to reduce the moisture of the material machinery and equipment, used for drying the object operation. Drying equipment through the heating of the material in the moisture (generally refers to water or other volatile liquid components) vaporisation escape, in order to obtain the specified moisture content of the solid material. The purpose of drying is for material use or further processing needs. Such as wood in the production of wood moulds, wood before the drying can prevent deformation of products, ceramic blanks in the calcination before the drying can prevent cracking of the finished product. In addition, after drying the material is also easy to transport and storage, such as the harvested grain dry to a certain moisture content below, in order to prevent mould. As natural drying far from meeting the needs of production development, a variety of mechanised drying equipment is more and more widely used.



Drying equipment for the drying process requires the consumption of a large amount of thermal energy, in order to save energy, some materials with high moisture content, containing solids suspension or solution is generally the first mechanical dehydration or heating evaporation, and then dry in the dryer to get dry solids.



Drying equipment in the drying process needs to be completed at the same time the transfer of heat and mass (moisture), to ensure that the partial pressure of moisture vapour on the surface of the material (concentration) is higher than the partial pressure of moisture vapour in the external space, and to ensure that the temperature of the heat source is higher than the temperature of the material. Heat is transferred from the high temperature heat source to the wet material in a variety of ways, so that the moisture on the surface of the material is vaporised and escapes into the external space, resulting in a difference in moisture content between the surface and the interior of the material. The internal moisture spreads to the surface and vaporises, so that the moisture content of the material is continuously reduced, and the drying of the material as a whole is completed gradually.