Today in 1904, US Patent 765112 A was issued, an invention of Robert Surry Valentine, for his “Beer-Cooler Tank.” There’s no Abstract, although in the description it includes this summary:

The object of the invention is to provide a construction of tank of the type referred to which will admit of the thorough cleansing thereof with facility; and to this end the invention includes the combination and arrangement of parts to be hereinafter described, and particularly pointed out in the claims.