ALEXANDRIA, Va., June 17 -- United States Patent no. 12,313,294, issued on May 27, was assigned to BESTWAY INFLATABLES & MATERIAL CORP. (Shanghai).

"PTC heater" was invented by Feng Liu (Shanghai), Xianglin Zeng (Shanghai), Qingshui Song (Shanghai) and Jiang Xu (Shanghai).

According to the abstract* released by the U.S. Patent & Trademark Office: "A heating apparatus is disclosed. The heating apparatus comprises a PTC heating element, a first electrode, a second electrode, a first protection layer, a second protection layer, a first interlayer, and a second interlayer. A hardness of the first protection layer is greater than that of the first interlayer. A hardness of the second protection layer is greater than that of the second interlay...