Abstract: The object of the invention is to provide a tubular fitting for connection to an overflow pipe on a sanitary silo in order to introduce sanitary air into any siphonal discharge therefrom and thereby reduce vacuum in the silo to prevent its collapse by implosion. The fitting (5) is generally tubularly Y-shaped with branch passageways (13) and (14) connecting an upper portion of an overflow pipe (3) with a sanitary air intake pipe (12), said branch passageways extending downwardly into an enlarged confluence region (15) which terminates in a single downwardly tapered passageway (16) for connection to a lower portion of said overflow pipe (3). The other object is to provide a sanitary air intake pipe (12) extending upwardly from an enclosed sanitary structure (4) into the fitting (5) thereby preventing unclean matter from entering the silo (1) during normal operation or when the silo is overfilled.