Appliance for cooking food, in particular fryer, comprising a catalyst and means for regulating said catalyst

FOOD COOKING APPARATUS, IN PARTICULAR FRYER, INCLUDING A CATALYST AND MEANS OF REGULATING THE SAID CATALYST

The present invention relates to the general technical field of food cooking appliances, of the fryer type, equipped with a means for treating cooking odors comprising a catalyst sub-assembly through which the flow or cooking vapors pass. before their release to the outside of the device.

The present invention relates to an appliance for cooking food in a closed atmosphere, of the fryer type for example, comprising a tank and a cover, means for heating the appliance, whether internal or external to the appliance, for carry out the actual cooking, and a catalyst to ensure the treatment of the odors of the flow or of the cooking vapors before the discharge of the said cooking flow to the outside of the appliance.

When cooking food, whether it is steaming in rice cookers for example, or cooking in oil in the case of fryers, the emission of vapors is observed. or more or less pronounced cooking flow depending on the cooking method and the cooking fluid used, this vapor emission exhibiting a characteristic odor generally little appreciated by the user and which it is precisely desired to avoid or treat.

One of the first known processing means obviously consists of cooking food in a closed atmosphere by making a sufficiently tight junction between the tank and the cover of the appliance.

Nevertheless, for obvious reasons of safety, in particular in pressure cookers or in fryers, it is always necessary to produce a leak in the cooking flow, and this is the reason why such devices are fitted with means for treating the cooking flows. cooking odors to rid the cooking flow of all or part of the volatile molecules responsible for the cooking odor.

Various devices have been envisaged, and the use of activated carbon filters making it possible to retain all or part of the fat, such as is for example described in patent FR-1,568,985 or in patent EP-150, is known in particular. 516 for example.

However, to be effective, the activated carbon filters must be frequently changed in the cooking appliance, which constitutes an additional constraint in the design of the appliance, insofar as it is imperative to provide for the design of a mounting system and for removing the activated carbon filter. Furthermore, it is observed that the user frequently forgets to change the activated carbon filter, such an operation being moreover perceived as a constraint. All these elements combine to make the use of activated carbon filters inefficient for the treatment of cooking odors. In addition, they are not absolutely and universally effective while leaving visible the flow treated then rejected and out of the device.

A system for treating the odors of fryers is also known which consists in condensing the cooking vapors in a condensing system mounted in the apparatus. Such a system does not have the drawbacks of changing all or part of the system as required by activated carbon filters, but requires on the part of the user relatively tedious handling at each cooking operation. Indeed, the condensing system must be kept at very low temperature, for example in a freezer, during all periods of non-use in order to be mounted in the cooking appliance itself before any cooking operation, especially since this system requires emptying the tank after cooking. Cold recharging does not allow a second cooking before 24 hours with the same system. This systematic assembly can be perceived as an additional constraint by the user. Furthermore, it turns out that condensing systems are generally of a large volume, which constitutes an additional design constraint, insofar as this system must be integrated into the cooking appliance, which should generally be limited. size.

Finally, it is already known to have recourse to catalysts, mounted in particular in fryers, to ensure the treatment of cooking odors. The use of catalysts avoids any specific handling compared to systems including activated carbon filters or condensation systems, since the catalyst is permanently installed in the device and therefore forms a permanent odor treatment unit.

On the other hand, it turns out that the use of a catalyst in food cooking appliances, and in particular in fryers, is difficult to implement insofar as the temperatures reached can be high and present a danger. for the integrity of the device and the user. Furthermore, it is necessary to reach sufficiently high temperatures in order to obtain a good yield and a good treatment of cooking odors, and to make the cooking vapors treated and rejected invisible. At the same time, it is not possible, for safety reasons, to favor too low operating temperatures of the catalyst, because the catalyst yield is then too low and the appearance of residual cooking odors is then observed.

It is therefore understood that the integration of catalysts in food cooking appliances, and in particular in fryers, is a delicate operation to perform, and that we are looking specifically to design food cooking appliances provided with catalysts but being able to operate under optimal conditions.

The object assigned to the invention therefore aims to remedy the various drawbacks of the prior art mentioned above, and to propose a new appliance for cooking food in a closed atmosphere equipped with a catalyst for the treatment of odors from cooking, which is able to function optimally using simple, safe and efficient means.

Another object of the invention aims to provide a novel cooking appliance, the catalyst of which is regulated in operation using simple and reliable means.

Another object of the invention aims to provide a new cooking appliance, the manufacturing cost of which is particularly under control.

Another object of the invention aims to provide a new cooking appliance, the catalyst yield of which is particularly high and obtained using simple and inexpensive means.

Another object of the invention aims to provide a novel appliance for cooking food in which the yield of the catalyst is particularly high and in which the release of steam is invisible.

A complementary object of the invention aims to provide a new cooking appliance whose safety of use is enhanced.

The objects assigned to the invention are achieved with the aid of an appliance for cooking food in a closed atmosphere comprising a tank and a cover, internal or external heating means of the appliance for carrying out the cooking and a catalyst. to ensure the treatment of odors from the cooking flow before the discharge of the cooking flow to the outside, characterized in that:

- the catalyst has at least one heating element,

- The apparatus comprises means for regulating the temperature of said heating elements, said means being arranged to sense the temperature of the cooking zone.

Other objects and advantages of the invention will emerge in more detail on reading the description which follows, with reference to the appended drawings given by way of illustrative and non-limiting examples in which:

- Figure 1 illustrates, in a general perspective view, a food cooking appliance according to the invention, in this case a fryer.

- Figure 2 illustrates, in a partial perspective view, an embodiment of the internal part of a fryer according to the invention.

- Figure 3 illustrates, in a partial cross-sectional view, a detail of embodiment and mounting of a catalyst according to the invention in the removable cover of a fryer.

In the embodiments illustrated in Figures 1 to 3, the food cooking apparatus according to the invention and described is constituted by a fryer intended for and designed for the realization of frying of food of all kinds in food. fatty matter, such as an oil bath for example.

For the purposes of the invention, it should nevertheless be understood that the term food cooking appliance covers all domestic food cooking appliances capable of cooking food, application to appliances. frying of the fryer type being only a preferred application, the invention obviously also being able to be applied to other applications such as rice cookers or multipurpose cookers, as soon as these cooking appliances carry out cooking in a cooking fluid contained in a substantially sealed closed chamber.

The food cooking appliance illustrated in FIGS. 1 to 3, in this case an electric fryer, comprises a base 1 intended to form the base of the appliance and intended to rest on a plane or a support. The base 1 is generally integral with an outer skirt 2 or attached to the latter, which is made, for example, of metallic material or of heat-resistant plastic material and forming the outer casing of the fryer. The outer skirt 2 is nevertheless conventionally made of an inexpensive plastic material with low heat resistance such as polypropylene, not resistant to the thermal energy continuously dissipated by the high temperature heating element (s) conventionally used in electric fryers, and generally placed at the bottom near the base 1.

The heating means of the device (not shown in the figures) can be internal to the device and conventionally composed of shielded elements or equivalent elements, also connected in a conventional manner to an electrical connection block (not shown) and to an electrical wiring allowing the device to be connected to the network. In a manner also known to those skilled in the art, the cooking appliance in accordance with the invention will be provided with all the electrical and electronic safety means such as temperature sensors, fuses, etc., required for the design of the appliance. these devices. These elements being well known to those skilled in the art, they will therefore not be described in more detail in the remainder of the description. The heating means can also be external to the device and separate or separable from the latter.

The outer skirt 2 may have any suitable and aesthetic geometric shape, for example circular, oval or rectangular, so as to define for example side faces 3 and front and rear faces 4.

The upper part of the outer skirt 2 will advantageously be provided with an annular ring providing the mechanical connection between the upper part of the outer skirt 2 and a cooking vessel 6, generally metallic, intended to receive the frying oil and the foodstuffs. to fry. Advantageously, and as is well known to those skilled in the art and for example from patent FR-87 06728, the annular ring will advantageously be made of a thermally insulating material and continuously resistant to the operating temperatures of the fryer, and for example made of polyamide, polyester, PBTP or the like, and will at least partially support the cooking vessel 6.

Within the meaning of the invention, the base 1, the outer skirt 2 as well as the annular ring will generally form the main body of the food cooking appliance according to the invention.

According to the invention, the fryer will include a cover 7 removably mounted, articulated relative to the main body of the fryer and intended to close, in a substantially sealed manner, for example by means of gaskets (not shown in the figures ), said main body during cooking.

Advantageously, and as shown in Figures 1 and 2 in particular, the cover 7 may be provided on its upper face 8 with a window 9 making it possible to monitor the progress of cooking or frying during the cooking cycle, and when the cover is closed on the main body.

Cooking food in a closed environment in a cooking fluid, whether steaming or frying, generates the production of characteristic and often unpleasant odors resulting from the chemical reactions associated with the cooking itself, and in particular to the emission of volatile organic substances.

The appliance for cooking food in a closed atmosphere therefore comprises a tank 6, a cover 8 and internal or external appliance heating means for cooking. It further comprises a system for heat treatment of cooking odors, namely a catalyst 10, to ensure the treatment of odors from the cooking flow before their discharge to the outside of the appliance.

According to the invention, and as illustrated for example in FIG. 3, the catalyst 10 comprises at least one heating element 11, the apparatus further comprising means for regulating the temperature 12 of said heating elements 11, said means 12 being arranged to sense the temperature of the cooking zone.

Thanks to this assembly, it is therefore possible to regulate the temperature of the heating elements 12 of the catalyst 10 by a thermal image which is not located in the catalyst itself but which corresponds to an image representative of that prevailing in the fluid. Cooking.

According to the invention, the temperature regulating means 12 comprise a temperature sensor 12A mounted so as to sense the temperature of the cooking vessel 6 as an image of the cooking temperature.

Advantageously, as illustrated in Figure 2, the temperature sensor 12A is mounted against or on the outer wall of the tank 6. The temperature sensor 12A can also be mounted against or on the inner wall of the tank 6 and be then in the same cooking bath. It is therefore against or on the side wall of the tank 6.

The temperature sensor 12A can be, in a manner well known to those skilled in the art, a thermostat (FIG. 2), a bimetallic strip or any other equivalent means such as a bulb or a shape memory alloy (SMA) for example. .

Advantageously, as illustrated in FIG. 2, the temperature sensor 12A will be mounted on the tank 6 at a height corresponding to the height of the oil bath, and for example halfway up the maximum height authorized for the bath. of oil. As a variant, the temperature sensor 12A could also be mounted against or on the bottom of the tank 6.

As is well known to those skilled in the art, the apparatus according to the invention also comprises a thermal regulation system (not shown) of the heating means, including for example a thermostat, said system being intended to ensure the thermal regulation of the device and of the oil bath according to the setpoint temperature displayed by the user.

According to a particularly advantageous version of the invention, the thermal regulation system of the heating means of the apparatus is associated with the thermal regulation means 12 of the temperature of the catalyst 10, said regulation system comprising a common temperature sensor with the thermal regulation means 12. According to this variant, the temperature sensor 12A serving to ensure the thermal regulation of the heating elements 11 of the catalyst, therefore also serves to ensure the thermal regulation of the heating means of the fryer. The thermal regulation of the catalyst 10 is therefore carried out by a single element, namely the thermostat (or an equivalent member) of the fryer. The corresponding electrical assembly therefore implies a parallel assembly of the resistances of the fryer and of the heating elements 11.

As a variant, it is obviously possible to carry out an assembly according to which the thermal regulation system of the heating means of the fryer is separated from the thermal regulation means 12 of the temperature of the catalyst 10, said system and said means each comprising a separate temperature sensor. According to the latter variant, the setpoint temperatures being different for each of the two thermostats, the efficiency of the catalyst can be increased.

According to a particularly interesting version of the invention, the catalyst is formed by a housing 15 which is mounted and integrated in the cover 8 of the apparatus.

The housing 15 contains a catalytic cell 16 forming the upper part of the housing 15 and extending in the vicinity of the outer face of the cover 8. The housing 15 also contains the heating elements 11 which extend in the vicinity and under the catalytic cell. 16 to heat it by radiation, without the appearance of hot spots. The housing 15 is provided with inlet orifices 17 for the cooking flow to be treated, said orifices 17 being for example formed through a lower stainless steel plate 18 of said housing 15 located substantially to the right of the cooking vessel, the elements of heater being interposed between the orifices 17 and the catalytic cell 16, and arranged substantially in line with said orifices 17.

Thanks to this arrangement, homogeneous and efficient heating of the curing flow to be treated is obtained, which ensures good operation and good efficiency of the catalyst.

Advantageously, the heating elements 11 are formed by an electrical resistance in the form of a coil or a helix, for example. In addition, it is particularly advantageous that the coil or helical resistor extends substantially over the entire surface of the catalytic cell 16 so as to obtain, thanks to the coil, a higher concentration of the electrical resistance 11 at the periphery of the catalytic cell 16. This arrangement greatly reduces the appearance of hot spots at the level of the catalytic cell, in particular towards its central part devoid of zones of change of direction corresponding to the branches of the coils.

Advantageously, and to obtain excellent efficiency in the treatment of odors, the heating elements 11 will have a maximum thermal load at most equal to 3 w / cm², and preferably less than or equal to 2.5 w / cm². This makes it possible to obtain a maximum temperature of the order of 600 ° C. during treatment, which prevents overheating and makes it possible to maintain homogeneity in the treatment of the vapors.

As illustrated in particular in Figure 3, the housing 15 is advantageously mounted in the cover 8 of the device, the latter being mounted on a joint A so as to be able to pivot between a closed position (Figure 3) and a position opening (not shown) in which the cover 8 is substantially vertical.

According to an advantageous feature of the invention, the heating elements 11 are connected to an electrical circuit comprising a switch 20, such as a microswitch associated with the position of the cover 8, such that the switch 20 cuts off the switch. power supply of the heating elements 11 as soon as the cover is opened or removed.

As illustrated in FIG. 3, the switch 20 is actuated by a rod 21 mounted for free longitudinal elastic sliding in a sleeve 22, so as to be flush in the rest position on the outside of said sleeve 22 by its end 23. In this free rest position, corresponding to the open position of the cover 8, the switch 20 opens the electrical circuit of the heating elements 1. On the other hand, when the cover 8 is closed, the end 23 of the rod 21 is engaged by the cover when it reaches its substantially sealed closed position, so that the electrical circuit of the heating elements 11 is closed. This arrangement ensures good safety of use by allowing automatic shut-off of the catalyst as soon as the cover is opened. This arrangement also allows the catalyst not to operate if the user needs to cook with manipulation in oil. If the cover is removed, the springs bringing the catalyst assembly vertically, it does not work, avoiding any risk of burns.

The safety of use of the apparatus can be increased by fitting a safety thermostat 25 in the apparatus in the vicinity of the catalyst 10. Thus, the apparatus according to the invention may comprise a room and safety thermostat 25, connected to the electrical circuit for supplying the heating elements 11, said thermostat 25 being arranged in the vicinity of the catalyst 10, and for example in a chamber (open or closed) adjacent to the catalyst 10, to detect the ambient temperature around the catalyst 10 and cut off the power supply to the heating elements 11 in the event of the set temperature being exceeded.

The room thermostat 25 is particularly useful for avoiding problems of overheating of the plastic parts in the event of temporary insufficient ventilation, the thermostat 25 then automatically cutting off the heating elements 11. During this momentary shutdown, the cooking vapors can escape without be treated, the catalyst then resuming its normal operation as soon as the temperature detected by the safety thermostat 25 is lower than the set temperature.

Advantageously, a plywood 26 can be integrated under the housing 15 and at a distance from the latter to provide a thermal brake and protect the plastic structure of the cover 8 in the event of temporary overheating.

Conventionally, the catalytic cell 16 may be made of a material of the cordirite, ceramic or null zirconia type with standard calibrated holes of 100 or 400 CPSI or of the foam type in the PPI supports for example, such as those from the SICAT Company.

The surface area of ​​the catalytic cell 16 is calculated so as to avoid pressure drops and so as to have an acceptable vapor speed passing through. By way of example, the base surface of the catalytic cell 16 could be 4000 mm.² for a height of approximately 30 mm minimum with calibrated holes of 200 or 400 CPSI. According to another variant embodiment, the catalytic cell may have a base area of ​​the order of 8,000 mm.² with a reduced height of 12 mm for calibrated holes of 200 or 400 CPSI.

During the cooking operation, the cooking vapors are directed towards the inlet E of the catalyst 10 so as to enter the orifices 17 after being distributed in an inlet channel located under and along said orifices of admission 17.

The cooking flow is then preheated or heated by passing over the heating elements 11, then is treated by catalysis by passing through and into the catalytic cell 16 before escaping and being rejected outside the fryer, preferably towards the rear via exit S.

In addition to the treatment of odors during passage through the hot parts of the catalyst, a pyrolysis of the oil vapors contained in the vapors takes place which ensures complete treatment of the cooking flow at its outlet.

The regulation system according to the invention consequently makes it possible to ensure a particularly effective treatment of the vapors and cooking flows thanks to the use of a catalyst, while implementing particularly simple and effective means of temperature regulation, and this under optimal security conditions. The rejection of the processed stream is also invisible.