System for heating and storing a liquid

A system for heating and storing a liquid, comprising a liquid storage tank;

• controlled heating means disposed at a predetermined level within said tank and immersed within the liquid accumulated therein, said heating means effecting controlled stratification of the tank interior into upper and lower liquid storage sections disposed, respectively, substantially above and below the level of said heating means, the liquid accumulated in said upper section being substantially at a first predetermined temperature and the liquid accumulated in said lower section being substantially at a lower second predetermined temperature;
• temperature sensitive first control means operatively connected to and controlling the operation of said heating means for substantially maintaining the liquid in said upper section at said first predetermined temperature;
• a liquid passage assembly interconnecting said upper and lower sections and including circulating means for controlled circulation of liquid from said upper section to said lower section;
• a first liquid outlet means communicating with said tank upper section;
• a second liquid outlet means communicating with said tank lower section;
• temperature sensitive second control means responsive to the liquid temperature in one of the tank sections whereby liquid substantially at said two predetermined temperatures is adapted to selectively flow through said outlet means from the tank interior;
• temperature sensitive third control means operatively connected to and controlling operation of said circulating means whereby a predetermined liquid temperature differential is substantially maintained between the liquid accumulated within the upper and lower sections;
• and inlet means communicating with at least one of the tank sections for introducing liquid into the tank interior at a temperature lower than either of said predetermined temperatures.