The air dryer can be classified according to different […]
The air dryer can be classified according to different characteristics such as operation process, operating pressure, heating method, wet material movement mode or structure. According to the operation process, the air dryer is divided into batch type (batch operation) and continuous type.
According to the operating pressure, the air dryer is divided into two types: atmospheric air dryer and vacuum air dryer. Operating under vacuum can reduce the partial pressure of moisture in the space and accelerate the drying process, and can reduce the boiling point of the moisture and the drying temperature of the material. Steam is not easy to leak. Therefore, the vacuum air dryer is suitable for dry heat-sensitive, easily oxidized, explosive and toxic materials, as well as occasions where moisture vapor needs to be recovered.
According to the heating method, air dryers are classified into convection, conduction, radiation, and dielectric types. Convection air dryer, also known as direct air dryer, is the use of hot dry media and wet materials in direct contact, the heat transfer by convection, and the generated steam away; conduction air dryer, also known as indirect air dryer It uses conduction to transfer heat from the heat source to the wet material through the inter-metal walls. The generated moisture vapor can be removed by vacuum depressurization, passing a small amount of purge gas, or condensing on the surface of a separate low-temperature condenser. This type of air dryer does not use drying media and has high thermal efficiency. The product is not contaminated, but the drying capacity is limited by the heat transfer area of the metal wall. The structure is also relatively complex and often operates under vacuum. The radiant air dryer uses each The radiator emits electromagnetic waves of a certain wavelength range and is selectively absorbed by the surface of the wet material and then converted into heat to be dried. The dielectric air dryer uses the action of a high-frequency electric field to dry the inside of the wet material.