Dry air and dry nitrogen purges draw moisture from the test space to create a lower Humidity Chamber environment.
Dry air cleaning units have a desiccant dehumidifier that uses an active desiccant material and a hygroscopic substance that causes drying in its vicinity to absorb moisture from the air. As ultra-dry nitrogen gas with a dew point of -70°C is introduced into the enclosed cavity, it expands and places the test item under pressure, removing any residual moisture from the test product and the internal Test Chamber environment.
Desiccant dehumidifiers work on a more complex principle, but perform exceptionally well in cooler climates or when there is a lot of moisture in the air.
Temperature and humidity environmental Test Chambers are often paired with a dry air purge system that lowers the humidity index inside the chamber at a rate much faster than natural.
Temperature-only rooms can also benefit from a dry air purification system if the user wishes to control residual moisture as the room temperature changes.
Dry nitrogen can also be used as a dry gas purge method.
