Dryer classification

Air dryers can be classified according to different characteristics such as operating process, operating pressure, heating method, movement of wet materials, or structure. According to the operation process, air dryers are divided into two types: batch type (batch operation) and continuous type.
According to the operating pressure, air dryers are divided into two types: atmospheric air dryer and vacuum air dryer. Operating under vacuum can reduce the partial pressure of moisture vapor in the space and accelerate the drying process, and can reduce the boiling point of moisture and the drying temperature of materials , The steam is not easy to leak, so the vacuum air dryer is suitable for drying heat sensitive, easy to oxidize, explosive and toxic materials and occasions where moisture vapor needs to be recovered.
According to the heating method, air dryers are divided into convection, conduction, radiation, and dielectric types. Convection air dryer, also known as direct air dryer, uses hot drying medium to directly contact wet materials, transfers heat by convection, and takes away the generated steam; conductive air dryer is also known as indirect air dryer It uses conduction to transfer heat from the heat source to the wet material through the metal partition. The generated moisture vapor can be removed by vacuum suction, a small amount of purge gas or condensation on the surface of a separate low-temperature condenser. This type of air dryer does not use drying medium, has high thermal efficiency, and the product is not contaminated, but the drying capacity is limited by the heat transfer area of ​​the metal wall, and the structure is also more complicated. It is often operated under vacuum; the radiant air dryer uses various This kind of radiator emits electromagnetic waves in a certain wavelength range, which is selectively absorbed by the surface of the wet material and then converted into heat for drying; the dielectric air dryer uses the action of a high-frequency electric field to make the wet material generate thermal effects for drying.
According to the movement mode of wet materials, air dryers can be divided into fixed bed type, agitated type, spray type and combined type; according to the structure, air dryers can be divided into box type air dryer, conveyor type air dryer, and drum type Air dryers, vertical air dryers, mechanically stirred air dryers, rotary air dryers, fluidized bed air dryers, jet air dryers, vibrating air dryers, spray air dryers, and Combined air dryer and many other types.

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