The double cone rotary vacuum dryer is a drying equipment that integrates mixing and vacuum drying. The process of vacuum drying is to place the dried material in a sealed cylinder, and use a vacuum system to continuously heat the dried material while vacuuming, so that the moisture inside the material diffuses to the surface through pressure or concentration differences. Water molecules (or other non condensable gases) gain sufficient kinetic energy on the surface of the material, overcome the mutual attraction between molecules, and diffuse into the low-pressure space of the vacuum chamber. They are then pumped away by a vacuum pump to complete the separation from the solid.

The double cone rotary vacuum dryer exhibits the following characteristics:

(1) During the vacuum drying process, the pressure inside the cylinder is always lower than atmospheric pressure, resulting in fewer gas molecules, lower density, and lower oxygen content. Therefore, it can dry easily oxidized drugs and reduce the chance of material contamination.

(2) Due to the direct proportionality between temperature and vapor pressure during the vaporization process, the moisture content in the material can vaporize at low temperatures during vacuum drying, achieving low-temperature drying, which is particularly suitable for the production of drugs with heat sensitive materials.

(3) Vacuum drying can eliminate the surface hardening phenomenon that is prone to occur during atmospheric hot air drying. This is because there is a large pressure difference between the inside and surface of the vacuum dried material, and under the pressure gradient, moisture quickly moves towards the surface, without surface hardening.

(4) Due to the small temperature gradient between the inside and outside of the material during vacuum drying, the moisture can move and collect independently due to the reverse osmosis effect, effectively overcoming the phenomenon of separation caused by hot air drying.