Definition by Wikipedia
A Exsiccator (also: Desiccator, lat. essiccare: drying out) is a chemical lab equipment, that is mainly in use for drying of solid chemical substances at the analytical and preparative chemistry.
A Exsiccator is usually a container made of thick glass or plastic, which is hermetically sealed by a flat flange lid. The lower part of the Exsiccator is separated by a perforated ceramic or plastic plate (sieve plate) and below it is filled with a desiccant. On the sieve plate is an open vessel (glass cup, bowl, tumbler or similar) that contains the material that needs to be dried.
In order to accelerate the drying process, suitable desiccators („vacuum dedicators“) may be evacuated. Such desiccators have a lockable shut-off cock connection for evacuation either in the middle of the lid or on the side wall.
The Exsiccator is not only used for drying of solvent-base substances. If connected to a vacuum pump it can also be used to remove air from a system or component (e.g. resin and silicone)
Another application is the storage of samples at constant humidity. For this purpose, the lower part of the Exsiccator is filled with a saturated salt solution. This sets a certain partial water vapor pressure depending on the salt and temperature used. With this method it is possible to put samples, which have a variable weight depending on humidity by water absorption, for weighing in a defined and comparable state. Also the storage of samples or workpieces under inert gas is possible and widespread.
R&G supplies only implosion-tested Exsicctors, resistant to a vacuum of up to -740 mmHg (absolute zero: -760 mm/Hg) with a loss of no more than 20 mmHg in 24 hours.
The upper transparent lid is made of polycarbonate and is connected to the lower part of polypropylene. The tightness is ensured by a ring of neoprene rubber, which is placed in a designated groove.
The lid is equipped with a polycarbonate sealing valve with a fine control (needle valve) made of polyethylene, by slight rotation, the air can be admitted.
The Exsiccators are provided with an inner liner which serves as a container for the calcium chloride or other desiccant (if required)
Directions of use:
• Remove the lid made of PC - add the sample
• open the sealing valve (needle valve) - connect the pump hose to the Exsiccator needle valve to establish a vacuum
• close the sealing valve