Today in 1915, US Patent 1128825 A was issued, an invention of Rudolph Troehler, for his “Keg-Soaking Apparatus.” There’s no Abstract, although in the description it includes this summary:

This invention concerns an apparatus used in connection with means and devices provided for cleaning barrels and kegs and more particularly in the manner in which this work is carried on in breweries. Washing and rinsing machines have been provided for this purpose which operate upon the kegs after they have been subjected first to a preliminary soaking whereby water is also admitted to them to clean and rinse them interiorly.

This invention relates more particularly to the apparatus which serves to administer this preliminary soaking to the kegs outside and inside, to introduce water into them and to deliver’ them thereafter to the washing and rinsing devices to be subjected to further treatment by them.