Abstract: A dehumidifier for flexible envelopes having a process side for dehumidifying air from the flexible envelope and a regeneration side for regenerating the dessicant used for dehumidification. A regeneration wheel containing a dessicant is rotatably mounted in a slot between the process and the regeneration compartments so that a first section of the wheel extends into the process compartment and a second section of the wheel extends into the regeneration compartment. The process and regeneration compartments are further divided by a plurality of partitions transverse to the wall forming the regeneration and process compartments. A stream of air is generated in the process compartment by means of a blower wheel which is driven by a motor in the lower regeneration compartment. The static pressure in the lower process compartment is slightly lower than the pressure in the lower regeneration compartment, thereby preventing migration of flammable gases to electrical parts in the lower regeneration compartment.