Today in 1938, US Patent 2109489 A was issued, an invention of John Daniel Le Frank, assigned to the American Can Co., for his “Liquid Filling Machine.” There’s no Abstract, but the description states that the “present invention relates to a machine for filling cans with liquids that have a tendency to foam and has particular reference to devices which minimize foaming of the liquid passing into a can, passages in the devices being automatically purged of any foam which may have accumulated during the filling of a preceding can.”