(57) A system for coupling a liquid filled container 1 to a duct 43 is provided with a valve coupling 9 which co-operates with the duct 43 to enable connection of the container 1 to the duct 43, and subsequent disconnection, while the valve coupling 9 is lowermost and therefore below the liquid level, without spillage.
Preferably the valve coupling 9 or a separate gas passage 101 has means 23,103 permitting escape of excess pressure while the container 1 is stored, means 38,103 admitting air during liquid outflow into the duct 43 and means 39 co-operating with the valve coupling 9 to assist closing of the valve coupling on disconnection.