an air heating means such as a burner or an air cooling means such as cooling coils and a blower not shown for delivering conditioned air having a relatively low humidity content to a header 24 outlet ducts 26 extend from the header 24 to the inlet duct 18 of the vibrating plenum chamber and are coupled thereto by the air seal 28 of the present invention it is to be understood that both the header 24 and the chamber 18 extend over a predetermined length to provide sufficient residency time of the material within the chamber for the material to become dry thus it is not uncommon to have on the order of from 8 to 20 such air inlet air outlet sealed connections 28 in a single system as previously stated the prior art air seal interconnection for the most part comprised a rubber or synthetic coated woven material providing a flexible sleeve to accommodate the relative motion between the chamber and the air delivery unit and yet provide a sealed air path therebetween however such fabric tended to be rapidly worn to the extent of developing air leaks such leaks generally initially developed at the corners of wrinkles.