ALEXANDRIA, Va., May 5 -- United States Patent no. 12,618,475, issued on May 5.
"Back flow valve" was invented by Pascual Hernandez Sanchez (Los Angeles).
According to the abstract* released by the U.S. Patent & Trademark Office: "A novel backflow valve for use in homes and apartments, which can serve to prevent back flow such as when there is downstream clogging, is described herein. The operational part of the valve includes a washer maintained with the valve housing and a floatable ball wherein in the non-engaged position allows for the free draining of water, and in the engaged position, when drain water is backflowing into the valve housing, the ball floats and engages with the washer to seal the opening and prevent further backflow....