Today in 1880, US Patent 229374 A was issued, an invention of Friedrich A. Bruns, for his “Apparatus for Purifying Air.” There’s no Abstract, although in the description it includes this summary:

The object of this invention is to furnish means for cooling and purifying the atmospheric air which is required for handling beer, ale, wine, and other fermented liquors during fermentation. These liquids are at present transferred by means of air compressing pumps from one cask to another, the air employed for forcing the liquids carrying microscopic organisms and inorganic impurities which impregnate the beer or other liquid and exert an injurious influence thereon. To prevent these organisms from entering the liquids I employ a cooling and purifying apparatus, through which the air is drawn by the air-pump, so that all inorganic and organic impurities are retained and destroyed, and thereby a perfectly pure air supplied for handling the liquids. Fermented liquors treated with air purified in such a manner keep better, become perfectly clear, and are not liable to deterioration.

My invention consists more especially of a cooling-chamber filled with ice and provided with a top screen covered with a layer of cotton or similar material, and of an acid-chamber, into which the air is drawn from the cooling chamber and minutely divided therein by a perforated distributer and screen, to be then conducted off for use. Referring to the drawings, A represents a cooling-chamber, which is filled with ice and provided at the bottom with a discharge pipe for the ice water and with a suitable water-seal.