WO2014195985A1

WO2014195985A1 - Fryer with perforated lid

Info

Publication number: WO2014195985A1
Application number: PCT/IT2014/000152
Authority: WO
Inventors: Luciano Ferrari
Original assignee: By Me S.R.L.
Priority date: 2013-06-03
Filing date: 2014-06-03
Publication date: 2014-12-11
Also published as: ITRM20130321A1

Abstract

The present invention concerns a fryer (10) equipped with a containment structure (11) inside which there is at least one frying vat (11') and with a perforated lid (20) comprising in sequence upon each other: a lower plate (21) with concave upward shape and provided with holes (25) in the vicinity of its center; a first intermediate plate (22) with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27) in the vicinity of the central portion and with means for opening/closing (28) of said holes (27), maintained at a predetermined distance from said lower plate (21) by means of a spacer element (26) and a top plate (23) with a concave downward shape, characterised in that it further comprises a second intermediate plate (22') with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27') in the vicinity of the central portion and with means for opening/closing (28') of said holes (27'), maintained at a predetermined distance from said first intermediate plate (22') by means of a spacer element (26').

Description

Fryer with perforated lid

The present invention concerns a fryer with perforated lid, in particular provided with means of control of the condensation degree of the vapor flow coming out from the holes of the lid.

More in detail said invention concerns to said fryer type, designed and realized in order to retrieve the nutritional properties of the food undergoing frying, and to allow to get a more crispy frying.

As is well known, generally fryers are constituted by a tank in which the cooking oil is entered. The food to be subjected to frying are then introduced in oil, preferably after accommodation in a special collection basket. The fryers are also usually equipped with a lid, which allows to reduce the smells of frying, in particular if provided with odor filter, located under the lid; a thermostat, which allows to control the temperature of cooking oil; a tap to drain the used oil.

The international application WO2010/086892, in the name of the same applicant, describes a perforated lid for containers for cooking foods, comprising holes for the passage of vapor and gas, generated from the food during cooking, which rise to the top and for the condensated vapor which falls downwards and means of cooling and condensation of the vapor that passes through said holes, and support means of said cooling means of vapor, wherein the cooling means of vapor consist in succession, starting from the cooking container and proceeding upwards, of a lower perforated plate, at least one intermediate perforated plate and a non-perforated top plate, and said support means of said cooling means are constituted by a lower spacer element, interposed between said lower plate and said intermediate plate and an upper spacer element, interposed between said intermediate plate and said top plate, as well as the fryer for use with said perforated lid.

The stated purpose of the lid and of the fryer forming object of this previous application is to prevent that food can be cooked at a too high temperature, preventing it from deteriorating and losing its organoleptic properties, while overcoming the limitations of similar solutions previously known that, providing for vent holes of saturated vapor favored the cooking of foods at low temperature, with a uniform distribution of the heat inside the pot, allowing the recovery of the vapor phase transformed into liquid phase, thus avoiding that the food under cooking could exceed 100 °C, and avoiding the phenomenon of degradation of vitaminic, proteinaceous and lipidic components, with containment of the energy requirements, but had the drawback that, since the vapor from the cooking by said lids came out of the cooking container with a certain pressure, they could not avoid a certain dispersion of the nutritional properties of foods. This drawback occurred despite the fact that, over the years, this type of lids were improved by arranging, above the vent holes of the saturated vapor and at a certain distance from them, a basket for collection and condensation of vapor, which at the same time does not prevent instead the passage of the gas towards the outside.

This type of perfected lids also presented the problem of a gradual heating of the basket of collection and condensation of the vapor, with the result that the amount of vapor that was condensed and returned to the cooking container was progressively reduced compared to the amount necessary to obtain the set cooking characteristics.

According to patent application WO2010/086892 was then proposed a lid that allowed to obtain a cooking of foods that did not degrade the quality of the foods itself and that allowed cooking at not excessively high temperatures, creating also a thermal insulation of the food compared to the surrounding environment, which allowed to increase the amount of condensed vapors that fell within the cooking container and at the same time kept unchanged the amount of both vapor and the exit gas.

This type of lid allows to achieve particularly valuable results in the case of fries. Indeed, thanks to the second perfected lid of WO2010/086892 it is possible to obtain a frying at only 97 °C, well below the 180 °C to which the oil is transformed into acrolein, which has been recognized as a carcinogen, but also below 140 °C at which the oil reaches the smoke point and produces the first toxic substances. In addition, the recirculation of condensed vapor, enables to turn the cooking vessel on which the lid was placed in a convection oven and cooled vapor, with the resulting benefits. Moreover, it does not reach the degradation temperature during cooking, the oil retains its organoleptic properties and can be used for further subsequent cooking, up to more than 50 consecutive hours of frying. Not only that, since it does not decompose during frying, the oil can be disposed of more easily.

The international application WO2012/020442, in the name of the same applicant, describes in particolar a fryer provided with a perforated lid, provided with means that allow to adjust the amount of vapor that is condensed and recirculated within the fryer.

Stated purpose of the lid of the fryer and the object of this earlier application is to ensure better cooking of food, being able to adjust the amount of vapor that is condensed and recirculated within the fryer and, with it, the cooking temperatures.

To this end, the lid described in WO2012/020442 is a perforated lid comprising holes for the passage of the vapor and the gases that rise upward and to the vapor condensate which falls downwards and means of cooling and condensation of the vapor that passes through said holes, and supporting means of said means of cooling vapor, which further comprises means for adjusting the flow of vapor.

In particular, according to WO2012/020442, the saturated vapors produced inside the tank of the fryer through the holes in the lower plate, undergoing an acceleration towards the outside of the cooking container and subsequently encountering the lower surface of an intermediate plate, in contact with which, being at a lower temperature, they undergo a partial condensation and fall by gravity downward, through the same holes and returning inside the cooking container. The intermediate plate consists in turn of the holes, above which is arranged a flow regulator element.

Finally, the lid is equipped with a top plate, above which a handle is mounted.

For almost the entire duration of the frying, the holes of the intermediate plate are kept closed and the top plate is not in contact with the hot vapor coming out of the fryer. After cooking, the flow regulator element is rotated, allowing the passage of the vapor, so that the latter comes into contact with the lower surface of the top plate, which, being more cold favors a greater condensation of the vapor. Condensation builds up and then falls in greater amounts on the surface of the intermediate and upper plate and flows downward through the holes.

The fundamental characteristic of the perforated lid of the fryer described in WO2012/020442 consists in the presence of a second plate of condensation, superior to the first plate of condensation, in which the vapor can reach, according to the position of the adjusting element, and which is located at a temperature lower than that of the first plate. On the lower surface of said top plate is then establishes a vapor liquid equilibrium that allows the condensation and the consequent recovery of a greater quantity of vapors.

The fryer lid according WO2012/020442 allows a considerable increase of the quality of frying, through the possibility of adjusting the amount of vapors which are condensed and the resulting control of cooking conditions, always keeping the cooking temperatures below the smoke point of the oil. However, after a first period following the opening of the holes of the intermediate plate, the top plate also increases its temperature, decreasing its ability of condensation of the vapors. Optimum utilization of the lid instead would require a greater ability of condensation.

In the light of what was said, it is evident the need for a solution that enables a more efficient adjustment of the amount of vapor that is condensed and sent back in the fryer, in particular counteracting the decreased ability of condensation with time of cooking, or with the increase of temperature of the upper plate.

Purpose of the present invention is therefore to provide a fryer and a lid that allow to overcome the limitations of the solutions of the prior art and to obtain the technical results previously described, through a process of progressive adjustment of the amount of condensed vapor.

A further aim of the invention is that said fryer and said lid can be manufactured with substantially limited costs, both as concerns production costs and as regards management costs.

Another object of the invention is to provide a fryer and a lid that are usable for the above said purposes of through a process of cooking substantially simple, safe and reliable.

It is therefore a first object of the present invention a fryer equipped with a containment structure inside which there is at least one frying vat and with a perforated lid comprising in sequence upon each other: a lower plate with concave upward shape and provided with holes in the vicinity of its center; a first intermediate plate with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes in the vicinity of the central portion and with means for opening/closing of said holes, maintained at a predetermined distance from said lower plate by means of a spacer element and a top plate with a concave downward shape, additionally comprising a second intermediate plate with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes in the vicinity of the central portion and with means for opening/closing of said holes, maintained at a predetermined distance from said first intermediate plate by means of a spacer element.

Preferably, according to the invention, said means for opening/closing of said holes comprise two discs rotatably mounted above the central portion of a corresponding intermediate plate and equipped at the bottom with protrusions, in number, position and size corresponding to those of the holes of the respective intermediate plate so that, in a first position of use, they close said holes and in a second position of use they move away the respective disc from the corresponding intermediate plate.

Additionally, it is a second specific object of the present invention a process of frying in a fryer provided with a lid comprising in sequence upon each other: a lower plate with concave upward shape and provided with holes in the vicinity of its center; a first intermediate plate with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes in the vicinity of the central portion and with means for opening/closing of said holes; a second intermediate plate with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes in the vicinity of the central portion and with means for opening/closing of said holes; and a top plate with a concave downward shape, said process comprising the following steps:

- bringing the cooking oil to the cooking temperature, maintaining in the closed position said means for opening/closing of said holes;

- immersing the food to be fried in the cooking oil, maintaining in the closed position said means for opening/closing of said holes;

- after 3/4 minutes adjusting said means for opening/closing of said holes of the first intermediate plate, so as to open the passage through its holes;

- after about two more minutes, adjusting said means for opening/closing of said holes of the second intermediate plate, so as to open the passage through its holes;

- after about two more minutes, removing frying foods from cooking oil.

The present invention will be now described, for illustrative but non limitative purposes, according to its preferred embodiments, with particular reference to the enclosed drawings, in which:

- figure 1 shows a perspective view of a lid of a fryer according to the present invention,

- figure 2 shows a perspective view of the lid of figure 1 , and of part of an underlying fryer according to the present invention,

- figure 3 shows a bottom perspective view of the lid and of the fryer of figure 2, and

- figure 4 shows an exploded perspective view of the condensation elements of the lid of figure 1.

Making reference to figures 1 and 2, part of a fryer 10 and of a lid 20 according to the present invention are shown. The fryer is composed of a containment structure 11 , inside which a frying vat (11', figura 3) is present, covered by the lid 20. The vat is made with a depth such as to allow to contain the same amount of oil of a traditional vat, while maintaining a larger area above the oil level. According to the purposes of the present invention, in fact, it is essential that the space included above the oil level and below the lid of the fryer is such as to allow the accumulation of a quantity of vapor greater than in the case of the fryers according to the prior art. For example, compared to a distance of 7cm generally existing between the maximum oil level and the lid, according to the present invention it is preferable that this distance is between 8 and 23cm.

The fryer 10 is provided with a discharge conduit (not shown).

The lid 20 is constituted by a lower plate 21 , which constitutes the element which is arranged above the cooking vat, on which are arranged in succession a first intermediate plate 22, a second intermediate plate 22, a top plate 23 and a handle 24.

With reference to Figure 3, the lower plate 21 has a circular shape and a convex downwards bottom surface, ie convex towards the cooking vat 11'. Near the center of the lower plate 21 a group of holes 25 is made, whose shape fitting creates channels for the passage of the vapor and gas coming out from the container for cooking and condensed vapor that returns in the vat of cooking. Said holes 25 have an appropriate diameter, and their position on the lower plate 21 defines, in the present embodiment, a circle, with the center arranged at the center of the lower plate 21.

With reference to Figure 4, the remaining elements of the lid 20 are shown in exploded view, mounted above the lower plate 21. The first of these elements is the first intermediate plate 22 mounted on the lower plate 21 by means of a lower spacer element 26 made of insulating material. According to the invention, the saturated vapors produced inside the vat of the fryer pass through the holes 25 of the lower plate 21 , undergoing an acceleration towards the outside of the cooking container. Said saturated vapors coming out from the holes 25 then encounter the bottom surface of the first intermediate plate 22, in contact with which, being at a lower temperature, undergo a partial condensation and fall by gravity downward, passing through the same holes 25 and returning inside the cooking vat.

The lower surface of the first intermediate plate 22 has a suitable concave shape so that the condensate created by said vapor accumulates on the lower surface and falls in greater quantities on the upper surface of the lower plate 21. The concave upward shape of the lower plate 21 facilitates the collection of the condensate and the flow of liquid substances inside the underlying cooking vat, by means of said holes 25.

The bottom surface of the first intermediate plate 22 can also have a corrugated profile, in such a way to increase the surface met by the saturated vapor, increasing the condensation effect of the first intermediate plate 22.

Additionally, the first intermediate plate 22 includes holes 27, in the vicinity of the center, the shaped form creating channels for the passage of vapor and gas coming from the lower plate 21 and the condensate vapor, which falls on the lower plate 21.

Above the first intermediate plate 22 it is mounted, with an interposed first flow regulator element 28 and a spacer intermediate element 26 Of insulating material, the second intermediate plate 22', which has the same characteristics of the first intermediate plate 22, but with a number of holes 27' which is greater than the holes 27 of the first intermediate plate 22.

According to the invention, as will be explained later, after a first period in which the flow regulator element 28 maintains closed the holes 27 of the first intermediate plate 22, to counteract the decreased ability of condensation of the first intermediate plate 22 due its increased temperature due to contact with the vapor from the cooking vat 11 through the holes 25 of the lower plate 21 , the flow regulator is actuated so as to open said holes, allowing the passage of saturated vapors, directed upwards. Said saturated vapors coming out from holes 27 of the first intermediate plate 22 then meet the lower surface of the second intermediate plate 22', in contact with which, this being at a lower temperature, undergo a partial condensation and fall by gravity downwards, through the same holes 27 and then falling to the lower plate 21 through the holes 25 of the latter returning inside the cooking vat 11'.

Also the lower surface of the second intermediate plate 22' has a concave shape so that the condensate created from said vapors accumulates on the lower surface and falls in greater quantities on the upper surface of the first intermediate plate 22. The concave shape towards the top of the upper surface of the first intermediate plate 22 facilitates the collection of the condensate and the flow of liquid towards the underlying lower plate 21 , by means of the holes 27 of the first intermediate plate 22.

Even the lower surface of the second intermediate plate 22' may have a corrugated profile, in such a way to increase the surface met by the saturated vapor, increasing the condensation effect of the second intermediate plate 22'.

The holes 27' of the second intermediate plate 22' are also practiced in the vicinity of the center, and have a contoured shape that creates channels for the passage of vapor and the gas coming from the first intermediate plate 22 and the condensate vapor that falls on the first intermediate plate 22.

Above the second intermediate plate 22' it is mounted, with interposed second flow regulator element 28', the top plate 23, above which is mounted to the handle 24.

The first flow regulator element 28 and the second flow regulator element 28' are both constituted by a disc 29, 29' fitted at the bottom with protrusions 30, 30', the position of which, the number of which and the dimensions of which are such as to coincide respectively with the holes 27 of the first intermediate plate 22 and with the holes 27' of the second intermediate plate 22', so that, suitably rotating the flow regulator elements 28, 28', each hole 27, 27' respectively of the first intermediate plate 22 and of the second intermediate plate 22' is closed by a corresponding protrusion of the respective flow regulator element 28, 28'. Each flow regulator element 28, 28' is also equipped with a respective handle 31 , 31', shaped as a lever which extends in radial direction with respect to the corresponding disc 29, 29'. On the upper surface of each disc 29, 29' is present a housing 32, 32' for a corresponding spring 33, 33', born superiorly by a respective ring 34, 34'. The function of said springs 33, 33' and of said ring 34, 34' is to push the respective underlying flow regulator element 28, 28' downward, allowing a certain degree of freedom of rotation with respect to the first or second intermediate plate 22, 22', at the same time ensuring the tightness of the coupling between the flow regulator element 28, 28' and the corresponding intermediate plate 22, 22'.

According to the invention, as will be explained later, even when the second intermediate plate 22 already began to heat up due to the contact with the vapors coming from the underlying first intermediate plate 22 after the opening of the corresponding holes 27 of the drive element to effect flow regulator 28, to counteract the decreased ability of condensation also of the second intermediate plate 22 ', due to its increased temperature, the corresponding element of the flow regulator 28' is actuated so as to open the passage through the holes 27' of the second intermediate plate 22', allowing the passage of saturated vapor, directed towards the top plate 23, with the effects which will be described later.

The top plate 23 has a concave downward bottom surface to promote the accumulation of the condensate created from the vapors in contact with the top plate 23, which is at a still lower temperature than the second intermediate plate 22'. In fact, due to the closure of the holes 27' of the second intermediate plate 22', obtained by the flow controller element 28', for almost the entire duration of the frying, and in particular for a time still longer than that of the closure of the holes 27 of the first intermediate plate 22, top plate 23 comes into contact with the hot vapor coming out of the fryer. When, in the last few minutes of cooking, as a result of heating also of the second intermediate plate 22', the flow regulator element 28' of the second intermediate plate 22' is rotated, allowing the passage of the vapors, the latter come into contact with the lower surface of the top plate 23, that, being colder, favors a greater condensation of the vapor. Condensation accumulates and then falls in greater amounts on the upper surface of the second intermediate plate 22' and through its holes 27', on the first intermediate plate 22 and later in the cooking vat 11'. The upper surface of the second intermediate plate 22' is concave upwards, to facilitate the collection of condensate and the flow of liquid down through the holes 27'. The bottom surface of the top plate 23 may have a corrugated profile, in such a way to increase the surface met by the saturated vapors going up, increasing the condensation effect of the top plate 23.

The diameter of the top plate 23 is smaller than the diameter of the intermediate plate 22, to allow the top plate 23 to deflect the vapor output respectively from the holes 27 of the intermediate plate 22 without halt the outflow.

All the described elements are equipped with a central pass through hole and are coupled together by means of a screw 35.

Based on the above description, it can be seen that the fundamental characteristic of the perforated lid of the fryer of the present invention consists in the presence of four superimposed plates, in which the lower plate 21 and the two intermediate plates 22, 22' are equipped with respective holes 25, 27, 27' for the passage of vapors and gases originating respectively from the frying vat 11' and the lower plate 21 and going up to the top, and the condensation that drops down and in which the two intermediate plates 22, 22' and the top plate 23 are equipped with a concave lower surface downwards for the condensate and the accumulation of vapor that comes in contact with said surface.

An advantage of the present invention over the prior art and in particular compared to WO20 2/020442 is therefore to provide a pair of intermediate plates for condensation, arranged between a perforated plate of condensation applied over the cooking vat 11' and a non perforated plate of condensation, to which vapor can reach according to the position of the regulator elements 28, 28', and that are at a progressively lower temperature than that of the first plate. The farther away from the cooking vat 11', the more on the lower surface of said plates of condensation a vapor liquid equilibrium is established more conducive to condensation and the subsequent recovery of a greater amount of vapor.

Additionally, the fryer 10 can be provided with a timer for the cooking time, as well as an hour-counter, which starts only at operating temperature, to keep track of the total hours of use of the fryer.

The operating conditions and the lid of the fryer according to the present invention, in comparison to those obtainable according to the prior art, are the following.

When the frying is done without affixing a closure lid of the pot used, usually a frying pan, the food that is being cooked and the cooking oil in particular can reach temperatures well above the smoke point of the oil, with consequent degradation of the organoleptic characteristics of the food.

When the cooking is carried out with a tightly closed lid on the pot, the internal temperature, both in the pot and in the fryer, reaches a maximum of 110 °C, due to the presence of water steam given off by the food during cooking. While this ensures healthy cooking, frying on the other hand may not crispy as would be desirable.

Through the lids described in WO2010/086892 and in WO2012/020442, it is possible to arrive at a maximum temperature of 120 °C, due to the partial condensation and recirculation of the vapor produced by food being cooked. The higher temperature allows to obtain a more crisp frying. When cooking frozen food, usually filled with ice, putting it into the cooking vat already at frying temperature, it produces a lot of vapor, which can compromise the crispness of the final product.

The according to the present invention can solve this problem by allowing a further increase in cooking temperature, without negatively affecting the condensation of the vapors and then on the recirculation of the condensate. So, according to the present invention, it is possible to make the most of the cooking at a lower level of temperature, with an increase of the same up to 120 °C in the final stages and even more up to 125 °C in the last moments before the end of the cooking. In this way, the food is cooked internally in optimum condition from a nutritional point of view and its outer surface is exposed to a higher temperature at the end of the cooking, taking a crunchy texture.

Taking into account that the fried food is cooked in generally 7/8 minutes, depending on the type of food and the size of the food itself, according to the present invention cooking proceed according to the following process:

- bringing the cooking oil to the cooking temperatures, within a fryer provided with a lid of the type that includes a lower plate 21 provided with holes 25 for passage, above which are arranged in succession: a first intermediate plate 22 provided with holes 27 and a flow regulator element 28, maintained in closed position of the holes 27, a second intermediate plate 22' provided with holes 27' and a flow regulator element 28', maintained in closed position of the holes 27'; a top plate 23, not perforated; - immersing the food to be fried in the cooking oil, maintaining in the closed position of the respective holes 27, 27' both the flow regulator element 28 and the flow regulator element 28';

- after 3/4 minutes, adjusting the flow control element 28 of the first intermediate plate 22, so as to open the passage through its holes 27

(vapor escapes in abundance, passing through the holes 27 and goes to condense on the bottom surface of the second intermediate plate 22', with the flow regulator element 28' maintained in the closed position of the holes 27', while the temperature in the cooking vat 11 rises of about 10 °C and makes the frying become crisp and the right consistency without the oil entering the interior of the food itself; the oil maintaining and not exceeding temperatures of 120 °C does not reach the smoke point and therefore does not denature, but most of its molecules remain unchanged and the food remains intact, preventing the formation of acrolein that, being toxic, could cause damage to organs such as the stomach, liver, the intestine);

- after about two more minutes, adjusting the airflow controller element 28' of the second intermediate plate 22', so as to open the passage through its holes 27' (an even better cooking result can be obtained because the food already led to an almost definitive point of cooking, as a result of this further opening passes through the holes 27' of the second intermediate plate 22' and goes to condense on lower surface of the top plate 23, while the temperature in the cooking vat 11 rises approximately of another 5 °C, remaining always below the smoke point, further improving the cooking result.

The advantages of the fryer according to the present invention are evident, which allows to obtain all the results that were set, resulting in a frying through which the oil retains its organoleptic properties and can therefore be used for further subsequent cooking (up to more than 50 consecutive hours of frying) and can be disposed of more easily, whilst ensuring crisp frying in a simple, safe and reliable way. Furthermore, the fryer according to the invention allows a considerable saving of energy and allows to fry cooking different foods at the same time without that their organoleptic characteristics are modified as a consequence of those of others.

The present invention has been described for illustrative, but not limitative purposes, according to its preferred embodiments, but it is understood that variations and/or modifications can be made by those skilled in the art without departing from the scope of protection as defined by the appended claims.

Claims

1) Fryer (10) equipped with a containment structure (11 ) inside which there is at least one frying vat (11 ') and a perforated lid (20) comprising in sequence upon each other: a lower plate (21 ) with concave upward shape and provided with holes (25) in the vicinity of its center; a first intermediate plate (22) with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27) in the vicinity of the central portion and with means for opening/closing (28) of said holes (27), maintained at a predetermined distance from said lower plate (21) by means of a spacer element (26) and a top plate (23) with a concave downward shape, characterised in that it further comprises a second intermediate plate (22') with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27') in the vicinity of the central portion and with means for opening/closing (28') of said holes (27'), maintained at a predetermined distance from said first intermediate plate (22') by means of a spacer element (26').

2) Fryer according to claim 1 , characterised in that said means for opening/closing (28, 28') of said holes (27, 27') comprise two discs (29, 29') rotatably mounted above the central portion of a corresponding intermediate plate (22, 22') and equipped at the bottom with protrusions (30, 30'), in number, position and size corresponding to those of the holes (27, 27) of the respective intermediate plate (22, 22') so that, in a first position of use, they close said holes (27, 27') and in a second position of use they move away the respective disc (29, 29') from the corresponding intermediate plate (22, 22').

3) Process of frying in a fryer (10) provided with a lid comprising in sequence upon each other: a lower plate (21 ) with concave upward shape and provided with holes (25) in the vicinity of its center; a first intermediate plate (22) with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27) in the vicinity of the central portion and with means for opening/closing (28) of said holes (27); a second intermediate plate (22') with concave upward shape in its central portion and concave downward shape in its side portion and provided with holes (27') in the vicinity of the central portion and with means for opening/closing (28') of said holes (27'); and a top plate (23) with a concave downward shape, said process comprising the following steps:

- bringing the cooking oil to the cooking temperature, maintaining in the closed position said means for opening/closing (28, 28') of said holes (27, 27');

- immersing the food to be fried in the cooking oil, maintaining in the closed position said means for opening/closing (28, 28') of said holes (27, 27');

- after 3/4 minutes adjusting said means for opening/closing (28) of said holes (27) of the first intermediate plate (22), so as to open the passage through its holes (27);

- after about two more minutes, adjusting said means for opening/closing (28') of said holes (27') of the second intermediate plate (22'), so as to open the passage through its holes (27');

- after about two more minutes, removing frying foods from cooking oil.