Materials and apparatus for the detection of contraband

摘要

A detector requires a stream of dry air for transporting particles to the detector. The detector then operates to determine whether the dry air has transported any particles of interest. Continuous operation of the detector is permitted by providing first and second dryers that can be operated alternately for drying air that is to be directed to the detector. The dryer that is not being operated is recharged. Air is directed alternately between the first and second dryer to ensure that neither dryer is operated after reaching saturation.