Deep fryer

Abstract

The present invention provides a deep fryer, which utilizes a heater (3) to heat frying oil stored in an oil tank (1) and performs frying and cooking of food materials put into the oil tank (1). The oil tank (1) comprises: an upper oil tank (1a) equipped with the heater (3) and performs frying and cooking of food materials; and a lower oil tank (1b) which is arranged at the lower part of the upper oil tank and is continuously arranged with the upper oil tank and allows water and oil residues emitted from the food materials to settle and be collected in the upper oil tank. The heater (3) comprises: a side heater (3b) which divides the upper oil tank (1a) into one or more cooking areas (5) and surrounds each cooking area (5); and a lower heater (3a) which is arranged at the bottom of each cooking area (5).

Description

Technical Field

[0001] The present invention relates to a fryer for cooking fried food, and more particularly to a fryer having a heater for heating frying oil provided in the middle of an oil tank in a depth direction. Background Art

[0002] Conventionally, this type of fryer is known to be constructed in the following manner: a heater is disposed in the middle of an oil tank storing frying oil in a depth direction, an upper oil tank above the heater is used as a high-temperature portion, and fried food is cooked in the upper oil tank, while a lower oil tank below the heater is used as a low-temperature portion, and water and oil residues produced in the oil during frying are allowed to settle in the lower oil tank.

[0003] As a specific means for keeping the lower oil tank at a low temperature, in the fryer disclosed in Patent Document 1, a heater is provided in the middle of the depth direction of the oil tank, and a porous plate is provided in a manner covering the heater from the top. A plurality of small holes are formed in the porous plate, and the flow of frying oil between the upper oil tank and the lower oil tank is subdivided through these small holes. That is, when food is first put into the upper oil tank, even if the frying oil in the upper oil tank boils due to the vaporization of water released from the food, the frying oil in the upper oil tank and the lower oil tank will not be agitated sharply due to the presence of the porous plate, and it is expected that the lower oil tank will be kept at a low temperature.

[0004] On the other hand, Patent Document 2 proposes to provide a water tank that covers the entire lower oil tank from the outside to forcibly cool the frying oil in the lower oil tank, thereby controlling the oil temperature in the upper oil tank to be suitable for cooking fried food, and suppressing the oil temperature in the lower oil tank to about 80° C. As an effect of maintaining the oil temperature in the lower oil tank at about 80° C., Patent Document 2 shows that the vaporization of water settled in the lower oil tank is prevented, the degradation of the frying oil caused by oxidation and the splashing of the oil in the upper oil tank are suppressed, and the oil residue settled in the lower oil tank is suppressed from rising into the upper oil tank due to convection and adhering to the fried food.

[0005] Prior art literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-294

[0007] Patent Document 2: Japanese Patent No. 5901624 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the fryers of Patent Documents 1 and 2, since the frying oil is heated only by the heater provided in the middle of the depth direction of the oil tank, the heater needs to generate a certain amount of heat. Therefore, the water released from the food into the frying oil in the upper oil tank has to pass near the heater with a large heat generation in the process of settling to the lower oil tank with a low temperature. That is, the water in the frying oil is vaporized in the process of settling from the upper oil tank with a high temperature to the lower oil tank with a low temperature, thereby causing oil splashing at the oil surface of the upper oil tank and deterioration of the frying oil accompanied by oxidation.

[0010] Solutions to Solve Problems

[0011] The present invention has been made in view of the above problems, and its object is to provide a fryer that can promote the sedimentation of water and oil residue released from food into frying oil relative to the lower oil tank, thereby suppressing oil splashing at the oil surface and deterioration of the frying oil.

[0012] That is, the present invention is a deep fryer, which uses a heater to heat frying oil stored in an oil tank and fry and cook food put into the oil tank, and the oil tank includes: an upper oil tank, which is equipped with the heater and performs frying and cooking of food; and a lower oil tank, which is arranged at the lower part of the upper oil tank and is continuous with the upper oil tank, and allows water and oil residues emitted from the food to settle and collect in the upper oil tank. In addition, the heater includes: a side heater, which divides the upper oil tank into one or more cooking areas and surrounds each cooking area; and a lower heater, which is arranged at the bottom of each cooking area.

[0013] Effects of the Invention

[0014] According to the present invention, since the frying oil in the upper oil tank for frying food is heated by both the side heater and the lower heater, the side heater divides the upper oil tank into one or more cooking areas and surrounds each cooking area, and the lower heater is arranged at the bottom of each cooking area, through the use of these heaters, it is possible to promote the sedimentation of moisture and oil residues released from the food into the frying oil relative to the lower oil tank, thereby suppressing the splashing of oil on the oil surface and the deterioration of the frying oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional view showing a first embodiment of a fryer to which the present invention is applied.

[0016] Figure 2 This is a plan view showing an example of a lower heater used in the fryer of the first embodiment.

[0017] Figure 3This is a plan view showing an example of a side heater used in the fryer of the first embodiment.

[0018] Figure 4 This is a cross-sectional view showing an example in which the upper oil tank is divided into two cooking areas by the side heaters.

[0019] Figure 5 This is a perspective view showing an example of a frying basket that can be applied to the fryer of the first embodiment.

[0020] Figure 6 This is a schematic diagram comparing the arrangement intervals of the lower heater and the side heater.

[0021] Figure 7 This is a cross-sectional view showing a second embodiment of a fryer to which the present invention is applied.

[0022] Figure 8 This is a cross-sectional view showing a third embodiment of a fryer to which the present invention is applied.

[0023] Fig. 9 This is a block diagram showing an example of a heater control system for a fryer to which the present invention is applied.

[0024] Fig.10 This is a flowchart showing an example of energization control of the heater. DETAILED DESCRIPTION

[0025] The fryer of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] Figure 1 The first embodiment of a deep fryer to which the present invention is applicable is shown. The deep fryer is a deep fryer of the type that is set on a table and used, and deep-frying oil 2 stored in an oil tank 1 is heated by a heater 3, and food is deep-fried and cooked in the deep frying oil 2. The housing 4 of the deep fryer is formed in a substantially rectangular shape, and a plurality of legs 40 are provided at the bottom, and an operating unit 41 having a main power switch is provided at the upper portion of the housing 4. In addition, a liquid crystal display that displays the current temperature of the deep frying oil and the like is provided on the operating unit 41. The oil tank 1 storing the deep frying oil 2 is provided in the center of the housing 4, and the heater 3 extending from the operating unit 41 is inserted into the oil tank 1.

[0027] The oil tank 1 is roughly divided into an upper oil tank 1a equipped with the heater 3, and a lower oil tank 1b continuously provided at the lower side of the upper oil tank 1a. The heater 3 heats the frying oil in the upper oil tank 1a, and the frying cooking of the food is carried out in the upper oil tank 1a. On the other hand, the water and oil residue released from the food into the frying oil during frying settles to the lower oil tank 1b and is collected by the lower oil tank 1b. Therefore, the bottom of the lower oil tank 1b, i.e., the bottom of the oil tank 1, is inclined, so that the settled oil residue is naturally accumulated at the bottom.

[0028] A gap 43 for air cooling the oil tank 1 is provided between the housing 4 and the oil tank 1. In addition, an air intake port 44 is provided at the bottom of the housing 4, and an air exhaust port 45 is provided near the upper end of the housing 4. When the frying oil 2 in the oil tank 1 is at a high temperature, the gas in the gap 43 is heated by the oil tank 1 and rises in the gap 43, and is discharged to the outside of the housing 4 from the air exhaust port 45. On the other hand, the gas outside the housing 4 is introduced into the gap 43 from the air intake port 44, thereby continuously air cooling the oil tank 1. However, the upper oil tank 1a is surrounded by the heat insulating material 42, so that only the lower oil tank 1b is cooled by the gas in the gap 43. That is, when the frying oil 2 in the upper oil tank 1a is heated by the heater 3, only the frying oil 2 in the upper oil tank 1a is kept at a high temperature, and the frying oil 2 in the lower oil tank 1b is actively cooled and kept at a lower temperature than the upper oil tank 1a.

[0029] As the heater 3, two types of heaters are provided: a lower heater 3a and a side heater 3b. The side heater 3b surrounds a cooking area 5 ( Figure 1 On the other hand, the lower heater 3a is arranged at the bottom of the cooking area 5.

[0030] Figure 2 : is a top view showing the lower heater 3a. The lower heater 3a is a so-called jacket heater in which an electrical insulating material and a nickel-chromium wire are built into a stainless steel support pipe, and is repeatedly bent at a predetermined interval and extended in the horizontal direction in the oil tank 2. Figure 3 3a is a top view showing the side heater 3b. The side heater 3b is a jacket heater similar to the lower heater 3a, and is bent into a rectangular shape so as to surround a predetermined partition in the upper oil tank 1a. Figure 1As shown, the bottom heaters 3a and the side heaters 3b are overlapped in multiple stages in the depth direction of the oil tank 1. The bottom heaters 3a and the side heaters 3b are arranged to be able to be popped up or detached relative to the oil tank 1, so that when the frying oil 2 in the oil tank 1 is replaced or the oil tank 1 is cleaned, the heaters 3 can be withdrawn from the wall of the oil tank 1.

[0031] In the upper oil tank 1a, the area surrounded by the lower heater 3a and the side heater 3b forms a cooking area 5 for food. That is, when frying food using the fryer, food is put into the bag-shaped cooking area 5 surrounded by these heaters 3. The cooking area 5 is provided with the side heater 3b around it, and the lower heater 3a is provided below the cooking area 5, so that the frying oil 2 in the cooking area 5 can be heated from the surrounding. Figure 1 In the example shown, only one cooking area 5 is provided in the upper oil tank 1a, but for example Figure 4 As shown, the interior of the upper oil tank 1a is divided into a plurality of cooking areas 5a and 5b, and the side heaters 3b are arranged so as to surround each cooking area.

[0032] Alternatively, switches for independently controlling the power supply to the lower heater 3a and the side heater 3b may be provided on the operation unit 41, and the user of the fryer may perform the on-off operation of each switch. However, from the viewpoint of frying at a constant temperature, it is preferred that the temperature of the frying oil 2 in the upper oil tank 1a is detected by a temperature sensor (not shown) at predetermined intervals, and the outputs of the lower heater 3a and the side heater 3b are controlled using the detection result. In addition, as shown in the embodiment described later, the outputs of the lower heater 3a and the side heater 3b may be controlled by also considering whether or not food is put into the oil tank 1.

[0033] It should be noted that although Figure 1 In the fryer shown, jacket heaters with circular cross sections are used as the lower heater 3a and the side heater 3b, but the jacket heaters applicable to the fryer of the present invention are not limited to these. For example, a jacket heater having a flat belt-shaped shelf pipe can be used for the side heater 3b. In addition, as for the side heater 3b, a coil for induction heating can be arranged outside the peripheral wall of the upper oil tank 1a, so that the peripheral wall of the upper oil tank 1a itself generates heat to heat the frying oil.

[0034] In the fryer of the first embodiment, food is put into the cooking area 5 surrounded by the lower heater 3a and the side heater 3b, and the food is fried and cooked. When food is first put in, a large amount of water is released from the food into the frying oil. In particular, when food such as frozen food or drained vegetables is put in, a very large amount of water is released into the frying oil. When the water is heated and vaporized by the frying oil, a large amount of bubbles is generated in the frying oil, and these bubbles burst on the oil surface to generate a large amount of oil splashing. In addition, the frying oil is deteriorated by oxidation.

[0035] On the other hand, the inventors of the present application have confirmed through experiments that, when frying food near the oil surface of frying oil, compared with frying food deep in frying oil, even if the same food is put in, the latter can suppress the generation of bubbles in frying oil and less oil splashing at the oil surface. In this regard, in the fryer to which the first embodiment of the present invention is applied, the side heater 3b surrounding the cooking area 5 is provided in the upper oil tank 1a and the cooking area 5 is formed into a bag shape, so that the food can be fried and cooked not near the oil surface but deep in the cooking area 5. Therefore, when the fryer is used, the generation of bubbles in the frying oil when the food is first put in can be suppressed, thereby suppressing the oil splashing at the oil surface and the progress of the deterioration of the frying oil 2.

[0036] Furthermore, in order to make the food sink deeper into the cooking area 5 for cooking, for example, Figure 5 The frying basket 50 with a lid is shown. The frying basket 50 is formed to a size that does not interfere with the side heater 3b and can be stored in the cooking area 5, and a lid 51 that can be opened and closed is provided on the upper part. In addition, the height H of the frying basket 50 is set to be smaller than the depth from the oil surface in the oil tank to the lower heater 3a. Therefore, if food is put into the frying basket 50 and the frying basket 50 is sunk into the frying oil 2 in the cooking area 5 to cook the food, the lid 51 prevents the food from floating up, so that the food can be forced to sink into the cooking area for cooking. Therefore, if the fryer and the frying basket 50 are used at the same time, the splashing of oil at the oil surface and the progress of the deterioration of the frying oil 2 can be further suppressed.

[0037] Furthermore, the water released from the food into the frying oil 2 in the cooking area 5 settles in the oil tank 1 due to the density difference with the frying oil 2. If the water quickly settles from the high-temperature upper oil tank 1a to the low-temperature lower oil tank 1b, the vaporization of the water can be suppressed, thereby suppressing the oil splashing at the oil surface. However, if the lower heater 3a is provided below the cooking area 5, the water needs to pass through the periphery of the lower heater 3a in the process of settling from the upper oil tank 1a to the lower oil tank 1b, and the water is easily vaporized by the heat of the lower heater 3a.

[0038] In this regard, in the fryer of the first embodiment to which the present invention is applied, the frying oil 2 in the cooking area 5 is heated by both the lower heater 3a and the side heater 3b, so that the power supplied to the lower heater 3a can be set smaller than when the frying oil 2 in the upper oil tank 1a is heated by only the lower heater 3a. Therefore, the water that escapes from the food into the frying oil 2 in the cooking area 5 is difficult to be vaporized when passing through the lower heater 3a and precipitates, and is easy to settle in the lower oil tank 1b. Thus, it is also possible to suppress oil splashing at the oil surface.

[0039] Furthermore, convection is generated in the frying oil 2 in the upper oil tank 1a due to the heating of the side heater 3b, so that the frying oil 2 near the side heater 3b becomes high temperature and rises to the oil surface, while the frying oil 2 near the oil surface falls in the upper oil tank 1a at the center of the cooking area 5. This phenomenon is particularly significant when the power supplied to the side heater is set to be larger than the power supplied to the lower heater. Therefore, the water and oil residue released from the food into the frying oil 2 in the cooking area 5 tend to settle to the lower oil tank 1b, and the water can be made to settle to the lower oil tank 1b as quickly as possible to prevent it from being vaporized, thereby suppressing the occurrence of oil splashing at the oil surface.

[0040] From the viewpoint of suppressing the vaporization of water released from the food into the frying oil 2 in the cooking area 5, Figure 6 As shown, it is preferred that the distance D between the sleeves of the lower heater 3a is larger than the distance d between the sleeves of the side heater 3b. By setting the distance D between the sleeves of the lower heater 3a to be larger, it is possible to reduce the possibility that the water in the frying oil 2 is heated by the lower heater 3a and vaporized when the water settles from the upper oil tank 1a to the lower oil tank 1b through the gap of the lower heater 3a, thereby suppressing the occurrence of oil splashing and oxidation of the frying oil.

[0041] Figure 7 A second embodiment of a fryer to which the present invention is applied is shown.

[0042] In the fryer of the second embodiment, a fall prevention plate 8 is provided inside the upper oil tank 1a to cover the lower heater 3a and the side heater 3b from above, thereby preventing the food being fried from sinking from the cooking area 5 to the lower oil tank 1b. The other structures such as the housing, the oil tank, and the heater are the same as those of the first embodiment. Figure 7 The same reference numerals as those in the first embodiment are used and detailed description thereof will be omitted here.

[0043] The drop prevention plate 8 is formed in a shape to be accommodated inside the oil tank 1, and is supported by the lower heater and the side heater and locked at a predetermined position in the oil tank, thereby vertically partitioning the oil tank 1. The drop prevention plate 8 is formed by bending a metal plate having a plurality of fine holes, and the frying oil 2 flows above and below the drop prevention plate 8 through the plurality of fine holes.

[0044] In addition, the drop prevention plate 8 has a recessed portion 80 at the center. The recessed portion 80 corresponds to the cooking area 5 of the upper oil tank 1a. When the drop prevention plate 8 is arranged in the oil tank 1, the recessed portion 80 is embedded in the inner side of the side heater 3b and covers the lower heater 3a from above, so that the drop prevention plate 8 isolates each heater 3a, 3b from the cooking area 5.

[0045] As described in the first embodiment, the food material put into the oil tank 1 sinks into the cooking area 5 surrounded by the side heater 3b and is fried in the cooking area 5. When the food material is first put in, a large amount of water released from the food material vaporizes in the frying oil 2 to generate a large amount of bubbles, and the frying oil in the upper oil tank 1a is likely to be rapidly stirred. However, even if it is rapidly stirred, the replacement of the frying oil 2 between the upper oil tank 1a and the lower oil tank 1b is slowly performed by the plurality of fine holes provided in the drop prevention plate 8. That is, by providing the drop prevention plate 8, it is possible to prevent the high-temperature frying oil in the upper oil tank 1a and the low-temperature frying oil in the lower oil tank 1b from being rapidly stirred, thereby preventing the water material that has settled in the lower oil tank 1b from floating up again and vaporizing, thereby preventing the oil splashing at the oil surface of the oil tank 1 from being reduced. Therefore, when frying and cooking food with a high moisture content, such as frozen food with frost or drained vegetables, the fryer of the second embodiment can more actively suppress oil splashing and deterioration of the frying oil than the fryer of the first embodiment.

[0046] Figure 8 A third embodiment of a fryer to which the present invention is applied is shown.

[0047] In the fryer of the third embodiment, a water tank 9 as a cooling jacket is provided in the housing 4, and water is poured into the water tank 9 to cool the oil tank 1 from the periphery. However, a heat insulating material 42 is provided between the upper oil tank 1a and the water tank 9 to prevent the high-temperature frying oil in the upper oil tank 1a from being cooled by the water in the water tank 9, so that only the frying oil in the lower oil tank 1b is cooled by the water in the water tank 9. It should be noted that since the other structures such as the housing, the oil tank, and the heater are the same as those of the first embodiment, Figure 8 The same reference numerals as those in the first embodiment are used and detailed description thereof will be omitted here.

[0048] A water injection pipe 90 for injecting water into the water tank 9 is connected to the water tank near the bottom of the housing 4, and a drain pipe 91 for discharging water from the water tank 9 is connected to the water tank 9 near the upper end of the housing 4. The water in the water tank 9 cools the frying oil 2 in the oil tank 1, so the water in the water tank 9 has the highest temperature near the upper end of the housing 4 and the lowest temperature near the bottom of the housing 4. Therefore, low-temperature water is injected from the outside into the bottom of the housing 4, and high-temperature water in the water tank 9 is discharged from the upper end of the housing 4, so that the frying oil 2 in the lower water tank 1b can be cooled while suppressing the amount of water injected into the water tank 9.

[0049] According to the fryer of the third embodiment, the frying oil 2 in the lower oil tank 1b can be actively cooled from the outside by the water in the water tank 9. For example, even if the oil temperature in the upper oil tank 1a is heated to about 180° C. by energizing the lower heater 3a and the side heater 3b, the oil temperature in the lower oil tank 1b can be maintained at about 80° C. As a result, the possibility of water released from the food in the upper oil tank 1a being vaporized by heating is significantly reduced as long as it passes through the lower heater 3a and reaches the lower oil tank 1b.

[0050] Furthermore, as described in the first and second embodiments above, in the fryer of the present invention, measures are taken to ensure that the water released into the frying oil 2 in the upper oil tank 1a reaches the lower oil tank 1b without being vaporized, thereby increasing the probability that the water reaches the lower oil tank 1b intact.

[0051] Therefore, in the fryer of the third embodiment, the water and oil residue released from the food into the frying oil 2 in the cooking area 5 are settled to the lower oil tank 1b as quickly as possible, and can be maintained in the lower oil tank 1b in the original state, thereby effectively suppressing the splashing of oil on the oil surface caused by the vaporization of the water and the deterioration of the frying oil caused by oxidation.

[0052] Next, a fourth embodiment of the fryer to which the present invention is applied will be described.

[0053] In the fourth embodiment, a control example of the lower heater and the side heater will be described. Fig. 9 1 is a block diagram showing a control system of the lower heater 3a and the side heater 3b. The lower heater 3a and the side heater 3b are connected to a power supply unit 6 that supplies power from an AC power supply, and generate heat by power supplied from the power supply unit 6. The power supply unit 6 is controlled by a control unit 7 having a built-in microprocessor. A temperature sensor 71 for measuring the temperature of the frying oil 2 is provided in the oil tank 1. The control unit 7 refers to an output signal of the temperature sensor 71 at predetermined intervals, and instructs the power supply unit 6 to supply power to the lower heater 3a and the side heater 3b according to a pre-stored program, so as to maintain the frying oil in the upper oil tank 1a at a predetermined temperature (e.g., 180°C).

[0054] The program stored in the control unit 7 may be arbitrary. For example, the opening and closing of the power supply to the lower heater 3a and the side heater 3b may be proportionally controlled based on the output signal of the temperature sensor 71, or the power supply to the lower heater 3a and the side heater 3b may be controlled by PID control. Furthermore, a difference may be set between the power supplied to the lower heater 3a and the power supplied to the side heater 3b according to the temperature change of the frying oil 2.

[0055] Furthermore, since a large amount of water is released from the food into the frying oil 2 when the food is first put into the high-temperature frying oil 2, it is effective to suppress the output of the lower heater 3a within a predetermined time after the food is put in, compared with before the food is put in, from the viewpoint of preventing the water from being vaporized and settling in the lower oil tank 1b. That is, even if the oil temperature of the upper oil tank 1a decreases due to the putting of the food, if it is estimated that a large amount of water exists in the frying oil in the upper oil tank 1a, control is performed such that the power supplied to the lower heater 3a is not increased, and only the power supplied to the side heater 3b is increased.

[0056] The control unit 7 checks the output signal of the food detection mechanism 72 to determine whether the food has been put into the oil tank. As the food detection mechanism 72, for example, a liquid level sensor for detecting the oil level in the oil tank 1 can be provided to determine whether food has been put in based on the change in the output signal of the liquid level sensor, or a light sensor can be provided at the opening of the oil tank 1 to directly detect the passage of food based on the change in the output signal of the light sensor. Furthermore, if food is put into the oil tank 1, the temperature of the frying oil 2 drops rapidly, so it is also possible to determine whether food has been put in based on the change in the output signal of the temperature sensor 71. With such a structure, the temperature sensor 71 can also be used as the food detection mechanism 72.

[0057] Fig.10 1 is a flowchart showing an example of a power-on control program for the lower heater 3a and the side heater 3b. When the main power switch provided in the housing 4 is turned on, the control unit 7 starts the power-on control program for the lower heater 3a and the side heater 3b. The control unit 7 reads the output signal of the temperature sensor 71, for example, every 1 second, and implements PID control according to a predetermined parameter, and sends a signal for controlling the power supply to the lower heater 3a and the side heater 3b to the power supply unit 6 (ST1). The power supply unit 6 receives the control signal and powers on the lower heater 3a and the side heater 3b. As a result, the temperature of the frying oil 2 in the upper oil tank 1a is controlled to the set temperature selected by the user.

[0058] On the other hand, when food is put into the cooking area 5 of the upper oil tank 1a with the start of frying cooking, the oil temperature of the upper oil tank 1a drops rapidly. The control unit 7 reads the output signal of the temperature sensor 71 and checks whether the rate of decrease of the oil temperature of the upper oil tank 1a (cooking area 5) reaches or exceeds a specified value (ST2). When the rate of decrease of the oil temperature is lower than the specified value, the PID control is continued based on the output signal of the temperature sensor 71 (ST1). Then, when the rate of decrease of the oil temperature is higher than the specified value, it can be determined that the food is put into the cooking area 5 and the oil temperature is decreased. In this case, regardless of the above-mentioned PID control, the power supply of the lower heater 3a is forcibly suppressed (ST3) for a specified time (for example, 60 seconds). That is, when the food is put in and the oil temperature of the cooking area 5 drops, the output of the side heater 3b is increased in order to obtain greater heat generation, but the output of the lower heater 3a is maintained at or lower than the output immediately before the food is put in, thereby suppressing the increase of the oil temperature around the lower heater 3a.

[0059] When food is first put into the cooking area of ​​the upper oil tank 1a, a large amount of water is released from the food into the frying oil. If the lower heater 3a is powered on before the large amount of water settles into the lower oil tank 1b, the water is heated by the lower heater 3a while settling from the upper oil tank 1a to the lower oil tank 1b and vaporized in the oil, and accordingly a large amount of oil splashes on the oil surface. In addition, the frying oil 2 in the oil tank 1 is also deteriorated. Furthermore, if a large amount of bubbles are generated near the boundary between the upper oil tank 1a and the lower oil tank 1b, the oil residue that is settling into the lower oil tank 1b also floats into the upper oil tank 1a.

[0060] Therefore, when it is determined that food is put into the cooking area 5, the lower heater 3a is forcibly turned off for a hesitation time, which is considered to be the time for a large amount of water released from the food into the oil to pass through the vicinity of the lower heater 3a and reach the lower oil tank 1b. As a result, the vaporization of water near the lower heater 3a is suppressed, so that splashing oil on the oil surface and deterioration of the frying oil 2 can be suppressed.

[0061] Then, after a predetermined time has passed since the forced suppression of the power supply to the lower heater 3a began, it is checked whether the main power switch is set to be closed (ST4), and the PID control is continued until the main power switch is turned off in the same manner as when the main power switch is turned on, thereby controlling the output of the lower heater 3a and the side heater 3b (ST1). In addition, after the main power switch is set to be closed, the power supply control program of the lower heater 3a and the side heater 3b ends.

[0062] By controlling the power supply of the lower heater 3a and the side heater 3b, the water and oil residue released from the food into the frying oil 2 can be promoted to settle into the lower oil tank 1b, thereby suppressing the splashing of oil on the oil surface and the deterioration of the frying oil 2.

Claims

1. A fryer, which uses a heater to heat frying oil stored in an oil tank, and fries and cooks food put into the oil tank. The fryer is characterized in that The oil tank has: an upper oil tank, which is equipped with the heater and is used for frying and cooking food; and The lower oil tank is disposed at the lower part of the upper oil tank and is continuously disposed with the upper oil tank, and allows the water and oil residue emitted from the food to settle and be collected in the upper oil tank. The heater comprises: a side heater, which divides the upper oil tank into one or more cooking areas and surrounds each cooking area; and The lower heater is arranged at the bottom of each cooking area. The power supplied to the side heater is set to be larger than the power supplied to the lower heater. The fryer also has: a control unit configured to control power supply to the side heater and the lower heater so as to maintain the frying oil in the upper oil tank at a predetermined temperature; and A food detection mechanism is used to determine whether the food has been put into the upper oil tank. When the food detecting means determines that the food has been put into the upper oil tank, the control unit suppresses the output of the lower heater relative to the output before the determination time within a predetermined time after the determination time.

2. The fryer according to claim 1, characterized in that When the rate of decrease in the temperature of the frying oil in the upper oil tank exceeds a predetermined value, the food detecting mechanism determines that the food has been put into the upper oil tank.

3. The fryer according to claim 1 or 2, characterized in that: The fryer is provided with a water cooling jacket which is arranged around the oil tank and forcibly cools the frying oil in the lower oil tank.

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