US Patent 6968888 Thermal receptacle with phase change material

A liquid receptacle for rapidly lowering the temperature of a liquid contained therein to a warm range suitable for human contact and maintaining the liquid in the warm range for an extended period of time includes an inner vessel with an open upper end and a closed lower end and a wall connecting the upper and lower end. An insulated outer shell is spaced from the inner vessel to define an interstitial chamber between the inner vessel and the outer shell. A phase change material occupies the chamber and regeneratively absorbs thermal energy from the liquid to cool the liquid and then releases the thermal energy back to the liquid to maintain the temperature of the liquid.