Food or edible material: processes – compositions – and products – Measuring – testing – or controlling by inanimate means – Preparing solid product in final form by heating
Reexamination Certificate
2000-05-02
2001-04-17
Yeung, George C. (Department: 1761)
Food or edible material: processes, compositions, and products
Measuring, testing, or controlling by inanimate means
Preparing solid product in final form by heating
C426S438000, C426S523000
Reexamination Certificate
active
06217923
ABSTRACT:
BACKGROUND ART
1. Field of the Invention
The present invention relates to a fryer, and more specifically to a fryer comprising a fry vessel containing water and oil therein and having an oil layer formed on a water layer due to a difference therebetween in specific gravity, and heating pipes, provided in the fryer vessel, for heating the oil layer, and cooling pipes, provided at a lower portion the fryer vessel than the heating pipes, for cooling the oil layer at the lower portion of the fryer vessel.
2. Description of Related Art
Fryers having an oil layer and a water layer are widely known from, for example, Publication of Examined Japanese Patent Application No. 55-40249. In the conventional fryer of the above-mentioned kind, water and oil are contained in a fry vessel, thereby forming a water layer and an oil layer, and a boundary surface therebetween is positioned at a slightly lower portion of the cooling pipes. Then, heating air heated by combustion gas and the combustion gas are passed through the heating pipes as heating fluid so that the oil layer of the fry vessel is heated. Then, air is passed through the cooling pipes as cooling fluid so that the lower portion of the oil layer is cooled. This restrains an acceleration of oxidation of the oil layer caused by an increase in temperature of the entire oil layer. At the same time, this prevents the temperature of the water layer of the fry vessel from being increased. Also, fry sediment and carbide deposited out of the heated oil layer are precipitated in the water layer so that they are prohibited from floating into the oil layer. This prevents deterioration of the oil layer caused by the fry sediment and carbide and generation of oil smoke caused by the carbide. For this reason, the necessity of an oil filtering process is eliminated, and an oil exchange cycle exists so that an amount of waste oil is lessened.
In the conventional fryer of the above-mentioned kind, however, the amount of the fry sediment and that of carbide, which are generated from fried food and precipitated in the water layer, are increased with an increase in the amount of the fried food. As a result, the boundary surface between the water layer and the oil layer rises. When the boundary surface comes close to the heating pipes, temperature of the water layer rises. As a result, there is an increased danger that steam explosion may occur on the boundary surface and heated oil may be scattered. In order to avoid such a danger, the user must carry out drainage to discharge the fry sediment and carbide from the water layer through a drain valve provided at the lower end of the fry vessel. For this reason, the user has to be conversant with the timing of when drainage should be carried out.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above-mentioned problem, and an object of the present invention is to provide 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 order to attain the above-mentioned object of the present invention, there is provided a fryer comprising a fry vessel containing water and oil therein, and having an oil layer formed on a water layer by a difference therebetween in specific gravity; heating pipes, formed in the fry vessel, for heating the oil layer; cooling pipes, disposed in the fry vessel at a lower portion of the oil layer than the heating pipes, for cooling a lower portion of the oil layer; water level detecting means for detecting the arrival of a boundary surface between the oil layer and the water layer to a first predetermined position located at the lower portion of the heating pipes; and oil layer heating control means, connected to the water level detecting means, for stopping the heating of the oil layer with the heating pipes by the detection of the arrival of the boundary surface at the first predetermined position.
In the fryer according to the present invention, the lower portion of the oil layer is cooled so as to restrain the acceleration of oxidation of the oil layer caused by an increase in temperature of the entire oil layer. At the same time, this prevents the temperature of the water layer of the fry vessel from being increased. Also, fry sediment and carbide deposited out of the heated oil layer portion are precipitated in the water layer so as to be prohibited from floating into the oil layer. And, this prevents deterioration of the oil layer caused by the fry sediment and carbide and generation of oil smoke caused by carbide. Moreover, in the fryer according to the present invention, the boundary surface between the water layer and the oil layer rises by the increase in the amount of fry sediment and that of carbide generated from fried food and precipitated in the water layer as the result of the increase in the amount of fried food cooked. At this time, a water level detecting means detects that the boundary surface has reached the first predetermined position of the lower portion of the heating pipes in the fry vessel. Then, an oil layer heating control means, connected to the water level detecting means, stops the heating of the oil layer with the heating pipes. For this reason, even a person, who is not conversant with the timing of when drainage should be carried out can avoid a danger that a steam explosion may occur on the boundary surface, thereby preventing heated oil from being scattered.
In the fryer according to the present invention, the water level detecting means preferably detects the arrival of the boundary surface to a second predetermined position in the lower portion of the fry vessel, whereby the oil layer heating control means restarts the heating of the oil layer through heating pipes with the detection of the arrival of the boundary surface to the second predetermined position after the detection of the arrival of the boundary surface to the second predetermined position by the water level detecting means.
In the fryer according to the present invention, in order to avoid the danger that steam explosion may occur on the boundary surface thereby scattering heated oil, the water level detecting means detects that the boundary surface has reached the first predetermined position of the lower portion of the oil layer in the fry vessel. Then, the oil layer heating control means stops the heating of the oil layer with the heating pipes. Thereafter, the user carries out drainage through the a drain valve provided at the lower end of the fry vessel to discharge the fry sediment and carbide, so that the boundary surface is moved downward away from the first predetermined position of the lower portion of the oil layer. As a result, when the danger is avoided, the water level detecting means detects the arrival of the boundary surface to the second predetermined position, and the oil layer heating control means restarts the heating of the oil layer with the heating pipes. For this reason, even if the user is not familiar with the fryer, intermittent detection time, and the time required for re-heating the oil layer can be reduced, thereby resulting in increased overall efficiency of the fryer and increased thermal efficiency of the fryer.
In the fryer according to the present invention, the oil layer heating control means preferably comprises alarming means for generating an alarm when the water level detecting means detects the arrival of the boundary surface to the first predetermined position. The alarming means may be an audio alarm such as a buzzer or a bell, or a visual alarm such as a lamp or a flashing light, or an alarm using a combination of both.
In the fryer according to the present invention, to avoid the danger that steam explosion may occur on the boundary surface and that heated oil may be scattered, a control system and control panel allow the user to immediately know that the
Bracewell & Patterson LLP
Bradley James E.
Yeung George C.
LandOfFree
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