A tobacco material expansion method includes the steps of wetting and swelling a tobacco material by bringing the tobacco material into contact with a water vapor stream at 100 to 160 C., and drying the tobacco material by bringing the wetted swelled tobacco material into contact with a superheated water vapor stream at a temperature higher than that of the water vapor.

Certain embodiments include a screen assembly of a vessel, where the screen assembly includes a plurality of fixed elements and a retainer, and the retainer includes a ring, a plurality of wedges disposed about the ring, and a plurality of keyholes at spaced locations about the ring. Each keyhole includes a bore and a slot extending from the bore into an adjacent wedge of the plurality of wedges, the slots have a width less than the bores, and the retainer may receive the fixed elements through the bores and may be rotated in a relation with the plurality of fixed elements to bring the plurality of fixed elements into simultaneous engagement with the wedges.

Certain embodiments include a screen assembly of a vessel, where the screen assembly includes a plurality of fixed elements and a retainer, and the retainer includes a ring, a plurality of wedges disposed about the ring, and a plurality of keyholes at spaced locations about the ring. Each keyhole includes a bore and a slot extending from the bore into an adjacent wedge of the plurality of wedges, the slots have a width less than the bores, and the retainer may receive the fixed elements through the bores and may be rotated in a relation with the plurality of fixed elements to bring the plurality of fixed elements into simultaneous engagement with the wedges.

The present disclosure relates to a smoking material including expanded tobacco leaves, wherein the expanded tobacco leaves are included in an amount of 50% by weight (wt %) or greater in the smoking material and prepared by a low temperature expansion process, relates to a method of preparing the smoking material, and relates to a smoking article including the smoking material, wherein the smoking material, including the expanded tobacco leaves prepared by the low temperature expansion process, has an excellent tobacco smoke taste.