There are many types of mechanical equipment used for drying operations, which can be divided into normal pressure and reduced pressure according to the operating pressure (reduced pressure dryers are also called vacuum dryers). According to the operation method, it can be divided into intermittent type and continuous type. According to the drying medium, it can be divided into air, flue gas or other drying medium. According to the mode of motion (material movement and drying medium flow), it can be divided into parallel flow, countercurrent flow and cross flow.

A mechanical equipment that uses heat energy to reduce the moisture of materials and is used for drying objects. The dryer vaporizes the moisture (usually water or other volatile liquid components) in the material by heating to obtain a solid material with a specified moisture content. The purpose of drying is for material use or further processing.

There are many types of mechanical equipment used for drying operations, which can be divided into normal pressure and reduced pressure according to the operating pressure (reduced pressure dryers are also called vacuum dryers). According to the operation method, it can be divided into intermittent type and continuous type. According to the drying medium, it can be divided into air, flue gas or other drying medium. According to the mode of motion (material movement and drying medium flow), it can be divided into parallel flow, countercurrent flow and cross flow.

According to the operating pressure, dryers are divided into two types: atmospheric dryers and vacuum dryers. Operating under vacuum can reduce the partial pressure of moisture vapor in the space and accelerate the drying process. It can also reduce the boiling point of moisture and the drying temperature of materials. Steam is not easy to escape. Therefore, vacuum dryers are suitable for drying heat-sensitive, easily oxidizable, explosive and toxic materials and occasions where moisture vapor needs to be recycled.

The vacuum rake dryer has simple structure, convenient operation, long service cycle, stable and reliable performance, small steam consumption, strong applicability, and good product quality. It is especially suitable for pasty materials that are not resistant to high temperatures, flammable, and easy to oxidize under temperature adjustment. Drying, this machine has been proved to be a good drying equipment through long-term use by users. Principle: The dried material is added from the top and middle of the shell. Under the stirring of the rake teeth that are constantly rotating forward and backward, the material moves back and forth axially. The surface in contact with the inner wall of the shell is constantly updated. It is indirectly heated by steam. The rake teeth are evenly stirred and crushed by the crushing rod, so that the moisture on the surface of the material can be discharged more favorably. The vaporized water passes through a dry dust remover, a wet dust remover, and a condenser, and is vented from the outlet of the vacuum pump.

The flash dryer uses hot air tangentially to enter the bottom of the dryer, and is driven by the agitator to form a powerful rotating wind field. The material enters the dryer from the screw feeder. Under the strong action of the high-speed rotating stirring paddle, the material is dispersed under the action of impact, friction and shear force. The block material is quickly crushed, fully contacted with hot air, heated, and dried. The dried materials are carried by the airflow into the dust collection system for collection and treatment. The exhaust gas with a dust content of "50mg/m3 is evacuated by an induced draft fan to complete the entire drying process.

A fluidized bed dryer is an enhanced special purpose drying device that is usually used for final drying of materials. Because mechanical vibration helps the material to be fluidized during the drying process, it not only facilitates boundary layer turbulence and enhances heat and mass transfer, but also ensures that the drying equipment works under relatively stable flow mechanics conditions. In addition to having a good drying function, this equipment can also be accompanied by processes such as material granulation, cooling, screening and transportation according to process needs. At present, it has been widely used in industrial sectors such as sugar production, medicine, chemical fertilizer, chemical industry, plastics, dairy industry, salt industry, and mining and metallurgy. This technology is basically mature and has been serialized.