Desiccants are used to absorb the water found in humid conditions to reduce or eliminate condensation. It can also be added directly to liquids to absorb the water content from the fluid. We are used to seeing the small white bags of desiccant found in packaging for everything from shoes to electronic equipment. Most of this desiccant is silica – typically in gel form. Other common substances used as desiccants are activated charcoal and calcium chloride.
The desiccant used in vapor degreasers is 3 Angstrom Molecular Sieve, small pellets of zeolite clay. Like all desiccants, the zeolite clay adsorbs water from the solvent, and may be reused by baking it dry. Desiccants are most often used in a vapor degreaser if the solvent contains an alcohol. This is often the case with solvents used for defluxing processes on soldered boards and leads. Water found in the separator extracts the alcohol from the solvent and in turn the water and alcohol is absorbed by the zeolite clay. If a degreaser is operated in a very humid environment a desiccant may be need to effectively remove the water from the solvent.