Today in 1939, US Patent 2147862 A was issued, an invention of Hans Sollinger, for his “Beer Dispensing Apparatus.” There’s no Abstract, but the description states that the “invention relates to a beer dispensing apparatus by means of which beer can be dispensed without pressure from barrels situated at a lower level than the faucet,” before going into more detail:

The apparatus is also suitable for dispensing wine and cider and has, in known manner, a packing ange against which the Vessel to be filled is pressed and hermetically closed by the suction action of the air pump. According to the invention the dispensing faucet of the apparatus is connected by a gearing with the air pump by which, when the apparatus is in use, the air is drawn out of the beer glass pressed against the packing surface and then, when the dispensing faucet is subsequently opened and during the filling of the glass, the excess carbon dioxide flowing into the glass passes into the pump whereupon, during the return movement of the gearing, the dispensing faucet is closed, and the air and excess carbon dioxide in the pump is returned by the pump to` the barrel through a filter.