There is provided a fryer, which can restrain an acceleration of oxidation of an oil layer, prevent deterioration of the oil layer caused by fry sediment and carbide and generation of oil smoke, and which is used easily and safely by even a person who is not conversant with timing when drainage should be carried out in accordance with an amount of fried food. The fryer according to this invention comprises a fry vessel 10 containing water and oil therein, and having an oil layer formed on a water layer by a difference therebetween in specific gravity, heating pipes 14, formed in the fry vessel, for heating the oil layer, cooling pipes 16, formed at the lower portion of the heating pipes in the fry vessel, for cooling a portion of the oil layer formed at the lower portion of each heating pipe, water level detecting means 40 for detecting the arrival of a boundary surface between the oil layer and the water oil to a predetermined position of the lower portion of each heating pipe, and oil layer heating control means, connected to the water level detecting means, for stopping the heating of the oil layer due to the heating pipes by the detection of the boundary surface.

This invention relates to a watering means for a fryer to supply suitable moisture required during frying operation. A fryer including a watering means for a fryer according to the invention comprises a heating device such as a heating pipe or a heater for heating oil in frying vessel to a temperature suitable for frying food, a net positioned above said heating means and a bottleneck-shaped accumulating portion positioned at lower portion of the fryer vessel to collect bits of fried batter. An injector having a plurality of perforation is provided in the frying vessel to supply water or vapor to frying oil.

The fryer has a frying vessel provided with an oil tank therein for storing hot oil during the cleaning operation. Cooling the oil and water boundary is accomplished by providing recessed portions in the walls of the frying vessel and by placing cooling pipes in the top of the tank. During frying, the tank itself is used as a cooling source for the water in the fryer.

A fat recirculating system with an external, gas-heated heat exchanger for a deep fat fryer is disclosed. The use of such a system necessitates recirculation also of cleaning solution and rinse water through inaccessible plumbing of the recirculation system whenever fat is to be replaced. To remove residual water droplets from the plumbing after rinsing, a "dry cycle" is utilized. The dry cycle includes intermittent application of heating and cooling of the empty heat exchanger, resulting in a substantial reduction in start-up time when the fryer is refilled and operation again commenced.

An Improved Deep Fat Frying System is disclosed which utilities heating elements controlled by triacs operated in the zero voltage switching mode by a programmed digital processor which can be used in a deep fat fryer and operated in a manner to minimize the maximum surface temperatures of the heating element surfaces during all phases of operation. The triacs together with the programmed digital processor allows the fryer to be controlled in all modes of operation to advantageously reduce peak power demand at various times during the daily operating cycle, to minimize maximum temperature required for efficient heat transference to the oil, and to reduce temperature overshoot. A method of operation has also been disclosed by which the maximum power consumption of a battery of two or more of the units can be minimized by maintaining a low power heat up during melt cycle or initial warm up all the way to a set point temperature.