Today in 1897, US Patent 581700 A was issued, an invention of Alvin James Donally, for his “Bottling Apparatus.” There’s no Abstract, but in the description it states that he’s “invented certain new and useful Improvements in Bottling Apparatus.” While he never summarizes what those are in a short, concise sentence, he does offer this.

It is highly desirable in the bottling of various liquids, and more especially in the bottling of ale and beer, to maintain gas or air pressure on the liquid both for the purpose of retaining the gas of the liquid in solution and for the purpose of effecting the delivery of the liquid into the bottles under a steady pressure, so that there may not be any material variation in the rate of flow, and it is also desirable to keep the liquid as far as possible from exposure to the air of the place where the bottling is carried on. It is of course desirable also to prevent the waste of the liquid which frequently occurs through the filling of the bottles to overflowing. Some of these objects have been attained in part hitherto; but so far as I am aware no apparatus has been devised as yet which will enable all of these objects to be attained in a satisfactory manner. Thus it has been sought to maintain the pressure on the liquid and to prevent the waste of liquid by providing in addition to the filling-tube a second tube, which returns or conducts to the barrel or other supply vessel the air displaced from the bottle, but this alone is not altogether satisfactory. It has also been proposed to maintain the required pressure of carbonic acid gas in the keg or barrel in which the liquid is delivered to the bottler. This is possible sometimes; but in some cases it happens that the keg or barrel is not capable of standing the gas-pressure which is necessary to force the liquid into the bottles. I have sought to provide in the first place for the separation in large part of the air displaced in the bottles from whatever overflow of liquid there may be, and for the escape of the air from the apparatus, and the return of the liquid to the supply vessel. I have sought also to provide for the admission of gas to the supply vessel without interference with the escape of the air and the return of the overflow. Furthermore, I have sought to provide for the handling of the liquid under gas pressure, in the manner already referred to, in cases where the original keg or barrel is not calculated to withstand gas pressure and the liquid can be drawn therefrom only by gravity.