The distributor plate, 1 mm thick, had
3 mm diameter holes on 6.2 mm triangular pitch. The distributor
was tightly fixed to the bottom of the column. Circular
holes 10 mm in diameter were cut at the base and top of the
microwave oven chamber to place the cylindrical chamber.
Metallic covers wereused at the inlet and outlet of the drying
air stream, to prevent microwaves from leaking out of the
oven. Since the ratio of cylinder diameter to height is much
greater than 10, the wall effect was negligible.