Gas Research Institute

John S Barnhart

Paul E George, Ii

Donald E Fritzsche

J Douglas Dickson

A gas-fired apparatus for high-volume commercial cooking comprises double-sided griddles, each having a lower platen with a horizontal top cooking surface and an upper platen with a bottom cooking surface. The upper platen of each griddle is moved into a horizontal position in contact with the food, presses downward on the food until it reaches a predetermined level above the lower platen, and stops there. It is lifted away when the food is cooked. Heated oil (maintained at substantially constant pressure by a weight controlled valve) is circulated through a first heat exchanger, which contacts, and transfers heat to, the lower platen, and through a second heat exchanger, which contacts, and transfers heat to, the upper platen. Each heat exchanger comprises three contiguous flat metal layers. The inner layer has a spiral-like passage for the oil to flow through, to heat an outer layer and maintain a substantially uniform temperature over its outer surface. Shape and dimensions for the passage may be determined in part by a finite element thermal conduction computer program. To minimize stresses in the inner plate and differences in thermal expansion among the layers, the passage may be cut out by a laser.

Heat exchanger

A gas-fired, double-sided griddle apparatus for high-volume commercial cooking comprises double-sided griddles, each having a lower platen having a horizontal lower cooking surface and an upper platen having an upper cooking surface; a positioning mechanism for moving the upper platen of each griddle into a horizontal position in contact with the food, permitting the upper platen to press downward against the food until the cooking surface reaches a predetermined level above the cooking surface of the lower platen, stopping the downward movement at that level, and lifting the upper platen away from the food after a predetermined cooking time; a counterflow heater for heating a supply of oil to desired temperatures; and apparatus for circulating the heated oil through a serpentine path wherein the oil contacts, and transfers heat to, a first region of the lower platen and a similar path wherein the oil transfers heat to a second region of the upper platen that is positioned directly above, and parallel to, the first region while cooking food located between the two regions of the platens. A weight controlled valve in the oil circulating apparatus maintains substantially constant pressure in the oil.

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Champaign, IL, United States of America

John S Barnhart