ALEXANDRIA, Va., March 3 -- United States Patent no. 12,565,997, issued on March 3, was assigned to Rinnai Corp. (Aichi, Japan).
"Premixing apparatus" was invented by Katsuya Noritake (Aichi, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A premixing apparatus that mixes a fuel gas with air and supplies an air-fuel mixture in a burner through a fan includes a control device that is configured to carry out a third control that: calculates and memorizes a lower limit of a rotational speed of a fan, at which an increase of an opening degree of a variable throttle valve becomes necessary, as a first threshold; and when the rotational speed of the fan increases to the first threshold or faster next time, im...