Today in 1979, US Patent DE 2751778 A1 was issued, an invention of Heinz Stricker, for his “Beer Piping Cleaning System — with suction nozzle for disinfectant inserted in tap water circuit.” Here’s the Abstract:
A system for the cleaning out of piping between bar barrels and the taps in a bar consists of a hose which is coupled between a water tap and a beer tap and includes a suction nozzle. A beaker with a disinfectant is attached to the nozzle so that the flow of water entrains the disinfectant. The piping in the cellar is disconnected from the barrels and coupled together so that the fluid can rise to another beer tap and out into a sink. After a certain retention time the whole is flushed out with clean water. This provides a chemical cleaning in addition to the conventional sponge cleaning.