There are many types of mechanical equipment used for drying operations. According to operating pressure, it can be divided into normal pressure and decompression (vacuum drier is also called vacuum drier). According to the operation method, it can be divided into intermittent type and continuous type. According to the dry medium can be divided into air, flue gas or other dry medium. According to the motion (material movement and dry medium flow) mode can be divided into parallel flow, countercurrent flow and wrong flow.
According to the operating pressure, drying machine is divided into two categories, atmospheric pressure drying machine and vacuum drying machine, operation can reduce the moisture of the space in the vacuum steam partial pressure and speed up drying process, and can reduce moisture boiling point and material drying temperature, steam is not easy to leak, so the vacuum drying machine is suitable for drying heat sensitive, easy oxidation, explosive and toxic materials, and moisture vapor recovery