ALEXANDRIA, Va., June 12 -- United States Patent no. 12,295,540, issued on May 13, was assigned to Hilti AG (Schaan, Liechtenstein).
"Efficient filter cleaning" was invented by Xaver Hanslmeier (Mauerstetten, Germany) and Svenja Muller (Friedberg, Germany).
According to the abstract* released by the U.S. Patent & Trademark Office: "A method for operating a vacuum cleaning appliance, having a filter element, a filter element cleaning device, a control device, a turbine, a first pressure sensor and a second pressure sensor. The method includes operating the vacuum cleaning appliance to suck in the air stream through the filter element; determining a first pressure reference value; measuring the pressure difference between the first and seco...