Patent ID: 8191468

Claim:
A cooking utensil which comprises: an inner vessel portion; an outer shell portion having an inside diameter larger than of the inner vessel portion and a height as same as or longer than that of the inner vessel portion, said outer shell portion having a cylindrical shape, wherein said inner vessel portion is inserted into said outer shell portion to form a first layer space; a second layer which is formed between outer members of bottom of said first layer space and inner member of bottom of said second layer; a third layer which is formed between outer member of bottom of said second layer and inner member of bottom of said third layer; a fourth layer which is formed between outer member of bottom of said third layer and inner member of said fourth layer; a fifth layer which is formed between outer member of bottom of said fourth layer and inner member of bottom of said outer member; a first diaphragm member and a second diaphragm member; at least one thermostat wherein said at least one thermostat is situated within said first layer; at least one heat sensor, wherein said at least one heat sensor comprises of a liquid which is sensitive to heat; a thermal induction actuator, which selectively closes said first diaphragm member and said second diaphragm member according to temperature of the outer member of bottom of said inner vessel portion; a plurality of hot air passages, wherein said plurality of hot air passages are formed vertically in a part of the circumference of said outer shell portion; and a plurality of cool air passages, wherein said pluralities of cool air passages are formed vertically in a part of the circumference of said outer shell portion.