ALEXANDRIA, Va., Aug. 20 -- United States Patent no. 12,390,672, issued on Aug. 19.
"Respirator" was invented by Xiaojin Han (Charlotte, N.C.), Hongbing Xiang (Charlotte, N.C.), Licong Duan (Charlotte, N.C.), Wei Shi (Charlotte, N.C.) and Hang Tian (Charlotte, N.C.).
According to the abstract* released by the U.S. Patent & Trademark Office: "The present invention provides a respirator. The respirator (100) has an outer housing (103), a filter, and an end cover (104). The filter is arranged on the outer housing (103). Position-limiting devices matching each other are respectively provided on the end cover (104) and the outer housing (103), and are used for fixing the filter at the outer housing (103)."
The patent was filed on Feb. 4, 2022...