Today in 2013, US Patent 20130126009 A1 was issued, an invention of Tracey M. Killarney and Lawrence A. Kent, for their “System for Cleaning Beer Lines and Recovering Draft Beer.” Here’s the Abstract:
A beer recovery system which uses CO2 to blow unused beer backwards through the beer lines and back into a beer keg is disclosed.
Good in theory, but impractical in practice, as tap contamination occurs way more often at the nozzle than in the line – not to mention the economics of the process (especially for craft beer bars w/rotating taps that serve more from 5-gal kegs than 15’s).
Further, places like Williams (brewing supply house in SF Bay Area) sell tap plugs for about $3/each (3/4″ metal bottle brush attached to a plastic handle that’s easy to insert & extract & easily rinsed in hot water), so beer bars can insert them after closing, the remove & clean the next day. They’re a cheap preventative for those who have minibugs infiltrating their taps.