Séchage sous vide

What is drying?

Drying is a mass transfer process. All mass transfer processes involve moving mass from one location or phase to another. In the case of industrial powder drying, the liquid solvent to be removed is almost always water. This is typically done by applying heat, thus causing the water to evaporate.

Some of the most common types of industrial dryers include:

    • Convection drying – Also known as direct drying. Hot air is directly applied to the materials to be dried.
    • Contact drying – Also known as indirect drying. The walls of the vessel in which the ingredients are contained are heated. This is the basic mechanism according to which amixon® vacuum dryers operate.
    • Freeze drying – Also known as lyophilization. The solvent is first frozen, then sublimed. This means it goes from its solid frozen state to its gaseous state without ever passing through its liquid phase.
    • Supercritical drying – Also known as critical point drying. The water is boiled off in a superheated steam drying system.
    • Vacuum drying - The atmospheric pressure within the dryer is lowered so that fluids evaporate at a lower temperature.

What is vacuum drying?

Vacuum drying is a batch operation performed in an air-tight vessel. Using vacuum pumps, the pressure and humidity within the chamber are reduced. By lowering the atmospheric pressure within the chamber, the materials inside dry more quickly and at lower temperatures than in other types of industrial dryers. Because the temperatures are lower, vacuum drying is especially well-suited for drying heat-sensitive materials.

amixon® vacuum dryer models AMT and VMT dry their contents through contact with the indirectly heated walls. In this sense, vacuum drying is essentially contact drying in a vacuum.

Learn more about the vacuum drying process, its applications, and its advantages over other industrial drying techniques.