ALEXANDRIA, Va., June 19 -- United States Patent no. 12,329,994, issued on June 17, was assigned to 3M Innovative Properties Co. (St. Paul, Minn.).

"Respirator flow control apparatus and method" was invented by Garry J. Walker (Norton, Great Britain), Andrew Murphy (Binchester Moor, Great Britain), Desmond T. Curran (Nevilles Cross, Great Britain), Derek A. Parkin (Newton Aycliffe, Great Britain), Thomas I. Insley (Lake Elmo, Minn.) and Mark A. J. Fernandes (Leamington Spa, Great Britain).

According to the abstract* released by the U.S. Patent & Trademark Office: "A respirator has a shell that defines a breathable air zone for a user wearing the respirator. An air flow control system for the respirator has an air delivery conduit within t...