Today in 2009, US Patent EP 2025640 A1 was issued, an invention of Jan Nørager Rasmussen and Steen Vesborg, assigned to Carlsberg Breweries, for their “Cooling Device for a Beverage Keg.” Here’s the Abstract:

The present invention relates to a cooling device (10) for containing a collapsible beverage keg (12) to be cooled to a temperature of e.g. 5°-7° C. The cooling device comprises a thermally insulating container (14) comprising a housing having a base portion (18) from which an outer wall (20) extends upwardly defining an upper open end (20) and a movable lid (22) which provides access to the interior of the container when the lid is open and a waterproof sealing off of the container when the lid is closed. The container further defines a specific inner volume when the lid is closed. The keg is supported by the base portion and defines in a filled and non-collapsed state a specific beverage volume. A connector (24) is mounted to the container for connection to an external water hose (25) for receiving and introducing tap water into the interior of the container. A residual volume for receiving ice as a cooling medium is defined as the difference between the specific inner volume and the specific beverage volume, the residual volume constituting preferably 17,6% of the specific inner volume. The beverage container communicates with an external tapping cock (26) for supply of a beverage from the collapsible beverage keg, the tap water being provided through the external water hose.