Today in 1934, US Patent 1962322 A was issued, an invention of Frederick Lewis Staite Murray and Thomas Staite Murray, for their “Cooling Apparatus For Beer or Other Beverage Contained in Casks.” There’s no Abstract, although in the description it includes this summary:

The object of the invention is the provision of improvements in such apparatus and the invention consists broadly of apparatus comprising a heat interchanger constituting a self contained unit adapted to be mounted in the bung hole or other single hole in the wall of the cask so as to project into the beverage, said heat interchanger being adapted to be connected to an outside refrigerating system whereby a refrigerant is continuously circulated through it from said system, for cooling the beverage.