The need for keeping food warm at the table throughout dinner has long been felt. In recent decades the need for cooking at the table has also been added. Running electric wires to the table and using electric heaters is one way to meet the need for heat at the table. However, such a practice is cumbersome and presents the danger that people could trip over the wires and cause a painful accident. Electric wires could in principle be avoided by using batteries placed on or underneath the table. The problem with batteries is that they are expensive, have a limited lifetime and present the danger of exploding when accidentally shorted.
Traditionally another way to keep food warm or to cook on a dining table has been to use fires fed by some liquid or solid chemical. These present the well-known danger of accidentally burning people, sometimes seriously. In addition they burden the atmosphere with pollutants.
An ancient technique for cooking or keeping food warm has been to use a thermal storage system, often in the form of hot stones. The coupling of thermal energy has been done through simple proximity conductive or convective thermal coupling. The disadvantage of these systems is that one has no control over the temperature at which thermal energy is delivered and almost no control over its temporal and spatial distribution.
USPTO Backgrounds
USPTO Backgrounds