A Cornelius keg is a stainless steel cylinder which can hold a maximum of 130 PSI. There are three openings in the keg: a large central hole which, by its design, can only be opened when the keg is not pressurized, and two ports with valves which are only opened when a
hose with an appropriate fitting is attached to them. The central hole is used for filling and cleaning the keg, while the two ports are used to dispense the drink. Two metal tubes are attached to the ports on the inside of the keg. The "gas-in" port has a short tube, not reaching the fluid. The "liquid-out" port has a long tube which reaches to the bottom of the keg. When pressurized gas (usually Carbon Dioxide which carbonates beverages and Nitrogen for non carbonated) is forced into the "gas-in" port, it pushes the drink from the bottom of the keg, out of the "liquid-out" port, presumably to a tap.
Cornelius style (or Corny) kegs were used by the soda bottlers to deliver and dispense soda syrup. When the industry moved to BIB (Bag In Box) systems, the remaining kegs were used to deliver and dispense pre-mix soda - the type of soda sold from small trailers & at remote events. At one time, any soda kegs outside the system were likely stolen from one of the bottlers. But all used kegs sold today have been retired out of the system and were legally purchased from one of the bottlers.
Pin-lock kegs, also known as Coke kegs, were used by the Coca-Cola Company. These kegs use pin-lock type disconnects to connect & disconnect the gas and liquid lines. Pin-lock disconnects lock on with a twist of the collar.
Ball Lock kegs, also known as Pepsi kegs, were used by everyone else. These kegs use ball lock type disconnects to connect & disconnect the gas and liquid lines. Ball lock disconnects lock on by raising & then releasing a collar. They connect just like an air line fitting connects.
New Ball Lock kegs are being manufactured in Italy. Quality new kegs should last a lifetime of brewing and are an excellent long term investment.
