Abstract: Disclosed is a high efficiency deep fat fryer from whose fry tank fat is continuously withdrawn for heating and filtration. A pump circulates part of this fat through a helical- or serpentine-shaped finned-tube heat exchanger positioned between a gas-fired burner and the bottom of the fry tank. The remaining portion of fat is directed through a filter located in the bottom zone of the fry tank. The fryer includes a control system with sensors such as pressure switches for preventing damage to the fat at low flow rates and devices for expelling moisture trapped in the pump. The filter has an element of material such as carbon-impregnated cloth which may be quickly replaced without draining fat from the tank.

Abstract: A broiler for cooking food products has an upper heating unit located in a spaced relationship from the food and a lower heating unit in a close heat transfer relationship with the food. The upper unit is preferably a U-shaped radiant fire tube with a gas-fired power burner mounted at one end as a heat source. Hot flue products exiting the radiant tube are directed to the lower heating unit which is preferably a heat pipe assembly with evaporator and condenser zones for a working fluid. In one form the condenser zone includes a generally flat wall portion with a cooking surface defining a set of upwardly facing grooves. In another form the condenser zone is a series of generally parallel pipes that extend under the food in a horizontal, mutually spaced relationship. A movable rack supports the food and moves it into and out of a cooking relationship with the condenser zone of the heat pipe assembly.

Abstract: A boiler for heating liquid which combines a source of hot gases directed first along the inner wall of an annular tank in a tortuous path formed by fins disposed upon the inner wall and then along the outer wall of the tank through a jet-impingement heat transfer system.

Abstract: A heat exchanger for directing discrete jets of fluid against a heat exchanging wall is configured to establish relatively close spacing between the openings through which the jets are formed and a portion of the heat exchanging wall while providing relatively large volumes of space adjacent other portions of the heat exchanging wall. The large volumes of space permit passage of the fluid from adjacent the heat exchanging wall without disturbing the jet flow.

Abstract: A food cooker is illustrated in the form of a deep-fat fryer, in which the fat is isothermally heated to an operating temperature below a temperature range in which an unacceptably high rate of undesirable decomposition products formation occurs in the cooking liquid. The heat transfer process used is vaporization and condensation of a confined liquid essentially isothermally and substantially at the working temperature. Condensation of the heat transfer vapor takes place at an outer surface of the container for the fat. Heat is applied to the heat transfer liquid remote from the container, which having no heating element or elements intruding into its interior is easy to clean. Heat is transferred to the cooking fat by condensation of the heat transfer vapor essentially only as it is used by the load being cooked. Hot spots are minimized, so that the formation of undesirable decomposition products of the cooking fat is retarded.

Abstract: A food cooker is illustrated in the form of a deep-fat fryer, in which the fat is isothermally heated to an operating temperature below a temperature range in which an unacceptably high rate of undesirable decomposition products formation occurs in the cooking liquid. The heat transfer process used in vaporization and condensation of a confined liquid essentially isothermally and substantially at the working temperature. Condensation of the heat transfer vapor takes place at an outer surface of the container for the fat. Heat is applied to the heat transfer liquid remote from the container, which having no heating element or elements intruding into its interior is easy to clean. Heat is transferred to the cooking fat by condensation of the heat transfer vapor essentially only as it is used by the load being cooked. Hot spots are minimized, so that the formation of undesirable decomposition products of the cooking fat is retarded.

Abstract: Food preparation apparatus involves a heat transmitting zone and a heat source located remotely from the transmitting zone. Heat energy is transferred from the heat source to the transmitting zone by a fluid vapor which travels from the heat source to the transmitting zone, condenses upon the transmitting zone and then returns in a liquid state to the heat source.In one described embodiment of this invention, an oven is provided wherein a fluid enclosure within the oven walls confines the vapor which transfers heat energy from a central heat source to heat transmitting surfaces.