Today in 1876, US Patent 172085 A was issued, an invention of Thomas J. Byrne, for his “Improvement in Devices for Drawing Beer.” There’s no Abstract, although in the description it includes this summary:

My invention relates to improvements in that class of devices employed for forcing air into barrels, kegs,vand other similar vessels in order to produce sufficient pressure within the same to cause liquid contained therein to flow readily therefrom when the spigot or tap is open, the nature of which will be hereinafter fully explained by reference to the drawings, in which Figure 1 represents a horizontal section of an ice-box, with a barrel or keg contained therein, with my invention applied thereto. Fig. 2 represents a sectional view of the air pump. Fig. 3 shows a vertical section of the plug, and parts connected therewith. shows a detached view of parts.