ALEXANDRIA, Va., June 6 -- United States Patent no. 12,280,327, issued on April 22, was assigned to BULK TANK INC. (Park Hills, Mo.).

"Vacuum filter assembly for cleansing air for use in transfer of bulk, granular material as in conveying vehicles" was invented by David E. Sisk (Bonne Terre, Mo.), Peter Kemp (Crestwood, Mo.), Roger Breakfield (Farmington, Mo.), Andrew Boyer (Bonne Terre, Mo.) and Travis Kinneman (Fredericktown, Mo.).

According to the abstract* released by the U.S. Patent & Trademark Office: "A dust filtering and collection system for filtering dust and other debris particles from an incoming dust laden air stream, such air stream generally being used for conveying granular material into or from a bulk tank trailer, a rail...