Display device showing bubbling liquid - having an enclosure contg. low boiling point liquid

An advertising display device especially for drinks consists of a sealed enclosure with transparent walls contg. a liquid of low boiling point, a bubble forming device, a vapour space above the liquid and a heating device inside or outside the enclosure when the heat is applied bubbles are formed by the boiling of the liquid and rise to the vapour space. A state of equilibrium is reached at which the heat input is balanced by the heat losses at the pressure of the vapour in the vapour space. The system is sealed and does not require make-up fluid, introduction of gas by pumps, cleaning. It has a low energy requirement and no moving parts. It gives a realistic simulation of e.g. champagne.