A device for maxillary jawbone and dentition expansion andor retraction is configured for mounting within the mouth and connects the right and left halves of the skull. The spray drying equipment includes a primary drying chamber and a secondary drying apparatus which includes tubing having a length sufficient to increase the contact time between the drying gas and the dropletsparticles to dry the particles to the extent desired, at a drying rate and temperature which would be too low to provide adequate drying without the secondary drying apparatus. At least one oblique crease is produced in each corner of the crate, with one end located at the intersection between two horizontal creases and the other end located on an upper ridge of one side wall. Upon removal of such the snap-fittable cover, laundry may easily be inserted or removed. The cover member is configured and arranged to provide a lower pressure section and another section in the air passage when the dust collection fan rotates. The introduction of this second feed material stream may be performed at any location on the adsorbent chamber between a transfer point located immediately upstream of the point of the raffinate material stream withdrawal from the adsorbent chamber to a transfer point located immediately downstream of the point of extract material stream withdrawal from the adsorbent chamber.