Self-contained cooling device for food containers

Abstract From the Canadian patent

A self-contained cooling device for use in a container such as a food container to cool the contents of the container at any desired time includes a reservoir containing pressurized fluid. The reservoir is secured to the inside of the container to form an expansion chamber between the reservoir and the container. A tube communicates with the reservoir and extends into the expansion chamber, the tube normally being closed to prevent escape of pressurized fluid from the reservoir. When it is desired to cool the contents of the container the tube is opened so that pressurized fluid from the reservoir expands into the expansion chamber thereby cooling the expansion chamber, reservoir, and …