Surface hardening phenomenon and characteristics of double cone vacuum dryer

- Oct 15, 2018-

In the process of vacuum drying, the double cone vacuum dryer is mainly effective in placing the dried and bitter-free in a sealed cylinder, mainly by vacuuming the vacuum system and effectively heating the material to be dried. It is possible to diffuse the moisture inside the material to the surface through the pressure difference and the concentration difference. The water molecules can obtain sufficient kinetic energy on the surface of the material, diffuse into the low pressure space of the vacuum chamber after overcoming the mutual attraction between the molecules, and are pumped away by the vacuum pump. The separation from the solid is completed.


In the process of vacuum drying, the pressure in the cylinder of the double cone vacuum dryer will always be lower than atmospheric pressure to a certain extent. The product has few gas molecules, low density and low oxygen content, so it can dry and easily oxidize the medicine. To reduce the chance of material contamination.


The double cone vacuum dryer will be proportional to the steam pressure during the vaporization process. Therefore, when vacuum drying, the moisture content of the material can be vaporized at low temperature to achieve low temperature drying. It is especially suitable for the production of pharmaceuticals with heat sensitive materials.


The double cone vacuum dryer can effectively eliminate the surface hardening phenomenon caused by atmospheric hot air drying and to some extent, mainly because the pressure difference between the vacuum dried material and the surface is large, and the pressure gradient is generally used. Underneath, the moisture quickly moves to the surface without surface hardening.


Due to the small temperature gradient between the inside and the outside of the double-cone vacuum dryer during the vacuum drying process, the moisture can be moved and collected by the reverse osmosis to a certain extent, effectively overcoming the hot air drying. Loss. The viscosity of the material changes with its moisture content. The viscosity allows the material to agglomerate into pieces and adhere to the wall of the cylinder. After drying, it tends to adhere to the dust collector and the pipe wall. Pneumatic vibration and crushing devices can be used.


The allowable temperature of the material in a double cone vacuum dryer. The allowable temperature is the highest temperature that the material can withstand. Exceeding this temperature will result in a change in material potency, decomposition or discoloration.