Double cone rotary vacuum dryer is a drying equipment which integrates mixing and vacuum drying. The process of vacuum drying is to place the material to be dried inside the sealed cylinder, and heat the material continuously while vacuum-pumping with the vacuum system, so that the water inside the material diffuses to the surface through the pressure difference or concentration difference, and the water molecules (or other non-condensing gases) obtain enough kinetic energy on the surface of the material and diffuse to the low-pressure space of the vacuum chamber after overcoming the mutual attraction between molecules. It is removed by the vacuum pump to complete the separation from the solid. Therefore, the double-cone rotary vacuum dryer has the following characteristics:

(1) In the process of vacuum drying, the pressure in the cylinder is always lower than the atmospheric pressure, the number of gas molecules is small, the density is low, and the oxygen content is low, so that the drugs that are easy to oxidize can be dried and the chance of bacteria contamination of the materials can be reduced.

(2) Because the temperature of the wet component in the vaporization process is proportional to the steam pressure, when vacuum drying, the wet component of the material can be vaporized at low temperatures to achieve low temperature drying, especially suitable for the production of drugs with heat-sensitive materials.