Today in 1956, US Patent 2731027 A was issued, an invention of Carl L. Daun, for his “Beer Dispensing Apparatus.” There’s no Abstract, but in the description, he describes as an “invention relat[ing] to [an] apparatus for dispensing carbonated beverages without there by changing the gas content of the beverage while eliminating the losses customarily encountered in dispensing such beverages. He continues:

This apparatus is particularly useful in dispensing beer from barrels but is, as will be apparent, suitable for all liquids. According to present practice barrel beer is dispensed from a faucet connected to a tap rod projecting to the bottom of the barrel through a tap which serves to provide a fluid tight seal at the tapping hole. Beer is forced up the tap rod to the faucet by the gas pressure in the barrel. A pressure regulated gas (air or carbon dioxide) source is connected to the interior of the barrel through a gas check valve in the tap. Theoretically such a system will maintain the carbon dioxide gas content of the beer constant and the drawing should be uniform. In practice, however, various losses attributable to variations in the gas content caused by temperature and pressure deviations from the ideal are encountered to a greater or lesser extent.

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