Vacuum Drying

Vacuum drying is the process of removing bulk moisture from a wet solid by exposing the mixture to vacuum. Drying is an essential operation in many different processes and is found in the food processing, pharmaceuticals, agriculture, powders and textiles industries.

A vacuum system lowers the pressure inside a large drying vessel. As the pressure within the vessel lowers to the vapor pressure of the liquid, the moisture will vaporize. Heaters installed on the vacuum dryer increase the temperature of the vessel. This increase in temperature coupled with the decrease in pressure allows for very high evaporation rates to occur. Once in vapor form, the vacuum system removes the moisture from the dryer. A heat exchanger then condenses the water for storage or transportation, if desired.

Wintek has extensive experience in the vacuum drying industry and works closely with many of the dryer manufacturers. Generally, Wintek recommends liquid ring vacuum systems for dryer applications because they are more rugged and can handle liquid and solid process carryover better than other types of vacuum pumps. While most dryers use filtration to prevent their solid product from leaving the vessel, the filter does not capture everything. Wintek’s process vacuum systems are ideal in these scenarios. Liquid ring vacuum pumps still operate if small amount of process carryover are present. However, in the case the dryer does not use filtration, Wintek provides systems with knockout pot filtration vessels in the system package to protect the system from process carryover.

vacuum drying, condenser liquid ring vacuum system with a transfer pump

Wintek SN 18016: Vacuum Drying, Vapors Removed: 2,000 kg wet cake, 70% moisture (water). Operating Vacuum Level: ~250 Torr Peak, ~75 Torr Final