Freeze drying is the dehydration by sublimation from the frozen
state. Under vacuum environment the ice inside the raw material will directly be converted into
steam evaporation.
Freeze drying is also known as Lyophilisation or cryodesiccation. It is a low temperature
dehydration process that involves Freezing the product, lowering pressure, then removing the ice by
sublimation. Frozen food items are good example of Vacuum freeze drying , it retains nutritional
value better than other drying methods.
Vacuum Coating
In vacuum coating process metals can be vaporized and the
vapours condense on any solid surface under high vacuum condition.
vacuum coating or vacuum deposition is a family of processes used to deposit layers of material on
a solid surface. These processes operate at pressures well below atmospheric pressure. Decorative
coating on plumbing items and other hardware are good examples
Metallization
Metalizing is the general name for the technique of coating metal on
the surface of objects. Techniques for metallization started as early as mirror making.
Vacuum metallization is a form of Physical vapor Deposition (PVD), it is a process of coating a metal
such aluminium or copper to a non-metallic substrate through evaporation under vacuum condition.
When plastic parts are vacuum metalized their aesthetic and mechanical properties are improved.
Vacuum Impregnation
This is a process that removes the air from the pores
of a specimen and fills them with resin or other material.
Vacuum impregnation is also a process of sealing porosity without altering any other physical or
functional properties of the part. Electrical transformers core and coil windings are impregnated
with resin / varnish . Casting moulds are impregnated to seal the porosity.
Distillation
Vacuum distillation is the method of distillation performed under
reduced pressure which lowers the boiling point of most liquids.
A vacuum distillation is used when the boiling point of the compound or the solvent is too high
i.e. more than 150 deg.C, it is useful in order to distil the compound or solvent without significant
decomposition. So vacuum distillation is the perfect solution for elements that decompose when
heated at atmospheric pressure or that have high boiling points
Thin Film Coating
Thin film coating is a process of making thin layer of materials which are used to
develop filters, increase insulation or conduction, protect them from lights or create
reflective surfaces.
Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD) are two
most common types of thin film coating methods. Good quality of thin film with
high degree of purity and adhesiveness can be achieved only when good vacuum
level is created and maintained in the chamber.
