EP3086044A1 - Cooking apparatus performing a pyrolytic cleaning cycle - Google Patents

Abstract

A cooking apparatus comprises a cavity (2) and means for implementing a pyrolysis cleaning cycle in which the temperature of the cavity increases from an initial temperature (T i) to a pyrolysis temperature, temperature rise in time being implemented according to a first temperature curve (temp1). The means for implementing a pyrolysis cycle implement the rise in temperature over time according to a second temperature curve (temp2) when a firing cycle has been previously implemented and the initial temperature (T i) is greater than or substantially equal to a predetermined temperature.

Description

The present invention relates to a cooking apparatus comprising a cavity, such as a baking oven, implementing a pyrolysis cleaning cycle.

The invention also relates to a method of cleaning by pyrolysis.

When carrying out a pyrolysis cleaning cycle, the temperature in the cavity increases gradually from an initial temperature, generally the ambient temperature, to a temperature, called the pyrolysis temperature. Once the cavity reaches the pyrolysis temperature, the temperature is maintained for a predetermined period of time to destroy grease and dirt deposited on walls forming the cavity.

Thus, the pyrolysis cycle comprises a first phase in which the temperature of the cavity increases from the initial temperature to the pyrolysis temperature (generally a temperature between 480 ° C. and 500 ° C.) according to a temperature curve representative of the evolution of the temperature over time and a second phase in which the cavity is maintained at the pyrolysis temperature.

The same cooking apparatus may implement pyrolysis cleaning cycles having different durations, depending for example on a selection made by a user.

The time required for carrying out a pyrolysis cleaning cycle is prefixed.

As an illustration, a pyrolysis cleaning cycle has a duration of approximately 90 to 150 minutes.

In these pyrolysis cleaning cycles of different duration, the duration of the first phase is equal for all the cycles and the second phase varies according to the cleaning cycle by pyrolysis implemented, usually depending on the degree of soiling of the cavity.

The document EP 0 632 232 discloses an oven employing a pyrolysis cleaning cycle.

In this document, the pyrolysis cleaning cycle is carried out following a firing cycle in order to benefit from the thermal inertia of the cavity at a high temperature relative to the ambient temperature.

Naturally, when the pyrolysis cleaning cycle is carried out following a firing cycle, the time required for the cavity to reach the pyrolysis temperature is shorter than when the pyrolysis cleaning cycle starts with the cavity. at room temperature.

The present invention aims to further optimize the duration of a pyrolysis cleaning cycle while obtaining a good cleaning result.

For this purpose, the invention aims, in a first aspect, a cooking apparatus having a cavity and means for implementing a pyrolysis cleaning cycle in which the temperature of the cavity increases from an initial temperature up to at a pyrolysis temperature, the rise in temperature over time being carried out according to a first temperature curve.

According to the invention, the means for implementing a pyrolysis cycle implement the rise in temperature over time according to said first temperature curve when the initial temperature is below a predetermined temperature and according to a second temperature curve. when a firing cycle has been previously implemented and the initial temperature is greater than or substantially equal to the predetermined temperature, the second temperature curve comprising at least a substantially linear portion corresponding to a temperature range, the portion having a slope of greater value than the value of the slope of a portion of the first temperature curve corresponding to the temperature range.

Thus, when the pyrolysis cleaning cycle is implemented after the implementation of a firing cycle and the temperature of the cavity is greater than the predetermined temperature, the rise in temperature is faster. The pyrolysis cleaning cycle is therefore shorter than when the cycle starts with a cavity less than the predetermined temperature, for example the ambient temperature.

Therefore, when a user controls a pyrolysis cleaning cycle after a firing cycle is finished and the cavity is at a temperature above the predetermined temperature, the duration of the pyrolysis cycle is shortened.

Thus, in such a case, the rise in temperature over time of the cavity being faster, the power consumption is lower and the cooking appliance is made available more quickly to be used.

Furthermore, the heat is homogeneous throughout the cavity, particularly in the walls surrounding the cavity.

In addition, thanks to the thermal inertia of the cavity, the energy consumption is further reduced.

According to one characteristic, the cooking apparatus comprising a catalyst for neutralizing the fumes produced in the cavity during the pyrolysis cleaning cycle, the pyrolysis cleaning cycle comprises a first part in which the temperature of the cavity increases from the initial temperature. up to an activation temperature of the catalyst, and a second portion in which the temperature increases from the activation temperature of the catalyst to the pyrolysis temperature, said temperature range substantially corresponding to the second portion of the cleaning cycle by pyrolysis.

Thus, the rapid rise in temperature of the cavity is carried out once the catalyst is activated, the odors and fumes produced in the oven cavity being neutralized.

In addition, the enamel covering the walls forming the cavity being already hot, it is possible to raise the temperature in the cavity quickly without risk of breaking the enamel.

According to another characteristic, the cooking apparatus comprises an extraction fan for extracting the fumes produced in the cavity during the pyrolysis cleaning cycle, and extraction fan control means configured to control the fan in operation. extraction at a speed of rotation, the speed of rotation of the exhaust fan being a function of the temperature of the cavity.

Advantageously, the control means of the exhaust fan are configured to operate the exhaust fan at a minimum speed of rotation when the cavity is at the initial temperature and to increase the speed of rotation of the exhaust fan when the temperature of the cavity increases.

Thus, the extraction of the fumes from the fats burned during the pyrolysis is reduced at the beginning of the cleaning cycle by pyrolysis. At the beginning of the pyrolysis cleaning cycle, the catalyst is not activated and the fumes are not neutralized. Therefore, with this feature, the exhaust fan starts operating at a reduced rotational speed to reduce smoke extraction until the catalyst is active to neutralize odors and fumes.

In addition, in a case of an implementation of a pyrolysis cleaning cycle following a firing cycle, the extraction of unpleasant fumes generated by the vaporization of fats that have already been heated during the cycle cooking are avoided.

According to one characteristic, the means for implementing a pyrolysis cleaning cycle comprise heating means configured in such a way that the temperature of the cavity increases according to the first temperature curve or the second temperature curve.

According to one characteristic, the means for implementing the pyrolysis cleaning cycle comprise means for verifying the prior implementation of a firing cycle and comparison means for comparing the initial temperature with the predetermined temperature.

In one embodiment, the predetermined temperature is substantially equal to 100 ° C.

When the initial temperature has a value substantially greater than 100 ° C or equal to 100 ° C, and a preliminary cooking cycle has imparted a thermal inertia to the walls of the cavity, the risk of breaking enamel covering the walls of the cavity during a rapid rise in the temperature of the cavity is minimized.

According to another characteristic, the means for verifying the prior implementation of a cooking cycle comprise comparison means for comparing a cooking temperature to a predetermined cooking temperature.

In one embodiment, the means for implementing a pyrolysis cleaning cycle implement the rise in temperature according to the second temperature curve when the cooking temperature is greater than or substantially equal to the predetermined cooking temperature.

According to one characteristic, the means for verifying the prior implementation of a cooking cycle comprise means for comparing a cooking time of said cooking cycle with a predetermined cooking time.

In one embodiment, the means for implementing a pyrolysis cleaning cycle implement the rise in temperature over time according to the second curve when a cooking time is greater than or equal to a predetermined cooking time. .

According to another characteristic, the means for implementing the pyrolysis cleaning cycle comprise means for determining the period of time elapsed between the end of said at least one firing cycle and the beginning of the pyrolysis cleaning cycle and means comparing the determined period of time with a predetermined period of time.

The cooking apparatus thus comprises means configured to check whether the temperature of the cavity, as well as the walls surrounding it, are at a homogeneous temperature and sufficiently high so that the rise in temperature can be implemented according to the second Temperature curve without risk of breaking the email of the walls surrounding the cavity.

In one embodiment, the means for implementing a pyrolysis cleaning cycle implement the rise in temperature according to the second temperature curve when the period of time elapsed between the end of said at least one cooking cycle and the beginning of the pyrolysis cleaning cycle is less than or substantially equal to a predetermined period.

In one embodiment, the cooking appliance is a cooking oven.

According to a second aspect, the present invention relates to a pyrolysis cleaning method for a cooking appliance comprising a cavity and implementing a pyrolysis cleaning cycle in which the temperature of the cavity increases from an initial temperature to a temperature pyrolysis, the rise in temperature over time being implemented according to a first temperature curve.

According to the invention, the rise in temperature over time is carried out according to said first temperature curve when the initial temperature is below a predetermined temperature and according to a second temperature curve when a cooking cycle has been previously set. and the initial temperature is greater than or substantially equal to the predetermined temperature, the second temperature curve comprising at least a substantially linear portion corresponding to a temperature range, the portion having a slope greater than the value of the slope of the a portion of the first temperature curve corresponding to the temperature range.

According to one characteristic, the pyrolysis cleaning cycle comprises a first part in which the temperature of the cavity increases from the initial temperature to an activation temperature of a catalyst that neutralizes the fumes produced in the cavity during the cleaning cycle. by pyrolysis, and a second portion in which the temperature increases from the activation temperature of the catalyst to the pyrolysis temperature, the temperature range corresponding substantially to the second portion of the pyrolysis cleaning cycle.

According to another characteristic, the pyrolysis cleaning method comprises the control of a fan for extracting fumes produced in the cavity during the pyrolysis cleaning cycle, at a speed of rotation depending on the temperature of the cavity.

In practice, the control of the exhaust fan includes the operation of the exhaust fan at a minimum speed of rotation when the cavity is at the initial temperature, the speed of rotation of the exhaust fan increasing when the temperature of the exhaust fan increases. the cavity increases.

According to one characteristic, the pyrolysis cleaning method comprises the control in operation of the heating means for a predetermined period of time and at a predetermined power so that the temperature of the cavity increases according to the first temperature curve or the second temperature curve.

According to one characteristic, the pyrolysis cleaning method comprises checking the prior implementation of a firing cycle and comparing the initial temperature to the predetermined temperature.

According to another characteristic, the pyrolysis cleaning method comprises determining a period of time elapsed between the end of said one firing cycle and the beginning of said pyrolysis cleaning cycle, the rise in temperature over time being implemented. according to the second temperature curve when said determined period of time is less than a predetermined period.

According to another characteristic, the verification of the prior implementation of a cooking cycle comprises the comparison of a cooking temperature during the pre-cooking cycle with a predetermined cooking temperature.

In one embodiment, the rise in temperature over time is carried out according to the second temperature curve when the cooking temperature is greater than or substantially equal to the predetermined cooking temperature.

According to one characteristic, the verification of the prior implementation of a cooking cycle comprises the determination of the cooking time of the cooking cycle, and the comparison of the determined cooking time with a predetermined cooking time.

In one embodiment, the rise in temperature is carried out according to the second temperature curve when the cooking time is greater than or substantially equal to a predetermined cooking time.

According to one characteristic, the predetermined cooking temperature is substantially equal to 140 °.

According to another characteristic, several cooking cycles have been previously implemented, each cooking cycle having an associated partial cooking time, said cooking times corresponding to the sum of said several partial cooking times when the temperature of the cavity is higher. at the predetermined temperature between the implementation of the baking cycles.

The pyrolysis cleaning process has characteristics and advantages similar to those previously described in connection with the cooking apparatus.

Other features and advantages of the invention will become apparent in the description below.

• la figure 1 est un schéma représentant un four de cuisson selon un mode de réalisation de l'invention ;
• la figure 2 illustre des courbes de température mises en oeuvre dans un appareil de cuisson conforme à l'invention ; et
• la figure 3 illustre le procédé de nettoyage par pyrolyse selon un mode de réalisation.

In the accompanying drawings, given as non-limiting examples:

• the figure 1 is a diagram showing a baking oven according to one embodiment of the invention;
• the figure 2 illustrates temperature curves used in a cooking appliance according to the invention; and
• the figure 3 illustrates the pyrolysis cleaning method according to one embodiment.

The present invention finds application in a cooking appliance having a cavity, such as a cooking oven or a stove.

The figure 1 illustrates a profile diagram of a baking oven 1 having a pyrolysis cleaning feature.

The baking oven 1 has a cavity 2 formed by a set of walls 2a, 2b, 2c, and by the door 3 of the baking oven.

The set of walls 2a, 2b, 2c and the door 3 of the baking oven 1 forming the cavity 2 constitute the muffle of the baking oven 1.

On the figure 1 only an upper wall 2a, a rear wall 2b opposite the door 3 and a bottom wall 2c are visible.

The baking oven 1 further comprises a catalyst 4 having the function of neutralizing fumes and odors produced in the cavity 2 during the pyrolysis cleaning cycle. The catalyst 4 is located in this embodiment on the upper wall 2a.

An exhaust fan 6 is placed in a discharge duct 5. The exhaust fan 6 makes it possible to extract the fumes produced in the cavity 2 during the pyrolysis cleaning cycle. The exhaust duct 5 connects the interior of the baking oven 1, in particular the cavity 2, with the outside.

In the exemplary embodiment illustrated by the figure 1 , the exhaust fan 6 furthermore makes it possible to cool certain parts of the cooking oven 1, notably ensuring the cooling of the door 3, as well as of the electronic card (not shown) notably comprising electrical circuits configured to manage the operation of the baking oven 1.

The extraction of the fumes generated during the cleaning cycle by pyrolysis is carried out by venturi effect. Thus, during the passage of the cooling air of the door 3 in the duct 5a, the movement of air sucks the fumes from the catalyst 4.

When a pyrolysis cleaning cycle is carried out in the baking oven 1, the grease and dirt deposited on the walls 2a, 2b, 2c and the door 3 burn producing smoke and odors.

The fumes and odors pass through the catalyst 4 opening on the discharge pipe 5a, and are then brewed and directed by the exhaust fan 6 to the exhaust pipe 5 which leads them to the outside of the cooking oven 1 .

In the exemplary embodiment illustrated on the figure 1 the cooking oven 1 comprises heating means arranged on the upper part of the cavity 2 and on the lower part of the cavity 2.

These heating means comprise in an exemplary embodiment a high resistance 7a and a low resistance 7b.

In this embodiment, the high resistance 7a is located inside the cavity 2 and the low resistance 7b is located outside the cavity 2. This low resistance 7b heats the bottom wall 2c.

The high resistance 7a and the low resistance 7b are used to heat the cavity 2 during the cooking modes and during the pyrolysis cleaning cycle.

In this embodiment, the high resistance 7a has a maximum power of 2100 watts and the low resistance 7b has a maximum power of 1200 watts.

The baking oven 1 also comprises a stirring fan 8 placed in the cavity 2. This stirring fan 8 can be used during cooking modes, known as "rotating heat" or for certain phases of the pyrolysis cleaning cycle.

The stirring fan 8 is here considered as forming part of the heating means.

As will be described later, the heating means 7a, 7b, 8 are configured so that the temperature of the cavity 2 changes over time according to the first temp1 temperature curve or the second temp2 temperature curve.

The baking oven 1 further comprises at least one temperature sensor (not shown in the figure) for measuring the temperature inside the baking oven 1.

In general, the baking oven 1 comprises a temperature probe located in the upper part of the baking oven 1.

From the temperature measured by the temperature probe, it is possible to know the temperature in the center of the cavity 2 of the oven of cooking 1, the temperature of the enamel on the walls 2a, 2b, 2c or the temperature of the catalyst 4.

In the embodiment described, the temperature of the cavity 2 refers to the temperature in the center of the cavity 2.

The cooking apparatus 1 further comprises control and control means (not shown in the figure) managing the operation of the cooking apparatus 1, and in particular the operation of the means used during the implementation of a cleaning cycle by pyrolysis.

The figure 2 represents a first temp1 temperature curve and a second temp2 temperature curve. A temperature curve represents the evolution of the temperature T of the cavity 2 in the time t during the implementation of a cleaning cycle by pyrolysis.

The first temp1 temperature curve shows a rise in temperature T over time t. This temperature curve temp1 is followed when the cavity 2 is at a temperature below a predetermined temperature. In the illustrated example, the temperature of the cavity 2 is an ambient temperature.

The second temp2 temperature curve represents a temperature rise T in the time t when a firing cycle has been previously implemented and when the pyrolysis cleaning cycle starts, the cavity 2 is at an initial temperature T _i greater than the predetermined temperature. Here, this initial temperature T _i is about 160 ° C.

For example, the cleaning is carried out by pyrolysis after a firing cycle and the predetermined temperature has a value substantially equal to 100 ° C.

The value of 100 ° C has been empirically defined so that the temperature rise of the muffle has a good thermal inertia by minimizing the risk of breakage of the enamel.

Of course, the predetermined temperature could have other values.

A pyrolysis cleaning cycle comprises a first phase A1, A2 in which the temperature T of the cavity 2 increases gradually from an initial temperature T _i to the pyrolysis temperature T _p and a second phase B1, B2 in which the pyrolysis temperature T _p is maintained.

When no baking cycle has been implemented and a pyrolysis cleaning cycle is initiated, the initial temperature T _i is substantially equal to the ambient temperature or external temperature of the baking oven 1.

This ambient temperature can thus vary within a range of values of between 15 ° C. and 35 ° C. and has a typical value of 20 ° C.

When a firing cycle has been implemented, the initial temperature T _i is of course greater than the ambient temperature.

In general, the pyrolysis temperature T _p has a value between 480 ° and 500 °.

It will be noted that the first phase A1, A2 of the pyrolysis cycle comprises a first portion A1 ic, A2i-c in which the temperature of the cavity 2 increases from the initial temperature T _i to the activation temperature T _c of the catalyst 4, and a second portion A1c-p, A2c-p in which the temperature of the cavity 2 increases from the activation temperature T _c of the catalyst 4 to the pyrolysis temperature T _p .

Activation temperature T _c of catalyst 4 is understood to mean the temperature from which catalyst 4 is sufficiently hot to catalyze the fumes produced during a pyrolysis cleaning cycle.

The activation temperature T _c of the catalyst 4 is between 250 ° C and 350 ° C.

The pyrolysis temperature T _{p is} the temperature at which the cavity 2 must be maintained in order to efficiently perform the decomposition of the organic compounds.

The pyrolysis temperature T _p is arbitrarily defined and is greater than the theoretical temperature from which the decomposition reaction of the organic compounds begins.

When the initial temperature T _i has a value lower than the predetermined temperature, for example a substantially equal temperature at room temperature, the temperature of the cavity 2 increases over time according to the first temp1 temperature curve .

Indeed, as will be described later, the heating means (resistors 7a, 7b and system fan 8) are configured such that the temperature of the cavity 2 increases according to the first temp1 temperature curve.

When the initial temperature T _i is greater than or substantially equal to a predetermined temperature, after a firing cycle has been implemented, the temperature of the cavity 2 increases from the initial temperature T _i to the pyrolysis temperature T. _p according to the second temp2 temperature curve.

Indeed, the heating means (resistors 7a, 7b and stirring fan 8) are configured so that the temperature of the cavity 2 increases according to the second temp2 temperature curve.

It will be noted that when a firing cycle has been previously implemented and the initial temperature T _i is lower than the predetermined temperature when a pyrolysis cleaning cycle is initiated, the temperature of the cavity 2 increases until pyrolysis temperature T _p according to the first temp1 temperature curve .

The second temp2 temperature curve comprises at least one substantially linear portion temp2 (1) corresponding to a temperature interval I _T.

In the embodiment shown, the temperature range I _T substantially corresponds to the temperatures at the beginning and at the end of the second portion A1c-p, A2c-p of the pyrolysis cleaning cycle, i.e. the temperature range I _T corresponds to the interval between the activation temperature T _c of the catalyst 4 and the pyrolysis temperature T _p .

The portion temp2 (1) of the second temperature curve temp2 has a slope α2 of value greater than the value of the slope α1 of a portion temp1 (1) of the first temperature curve temp1 corresponding to the same temperature interval I _T .

Thus, the pyrolysis temperature T _p is reached more rapidly when the rise in temperature is implemented according to the second temp2 temperature curve.

It will be noted that this rapid rise in temperature is carried out once the activation temperature T _c of the catalyst 4 has been reached, the odors and fumes produced in the cavity 2 of the cooking apparatus 1 being thus neutralized.

In addition, the enamel is preserved from a possible breakage.

Furthermore, in one embodiment of the present invention, the extraction fan 6 operates at a rotation speed which is a function of the temperature of the cavity 2.

The operation of the exhaust fan 6 is controlled by control means (not shown in the figures) of the exhaust fan 6.

The exhaust fan 6 is operated at a minimum speed of rotation when the cavity 2 is at the initial temperature T _i .

When the temperature of the cavity 2 increases, the control means operate the exhaust fan 6 at a higher rotational speed.

With this feature, the extraction of odors and fumes from the grease and dirt burned at the beginning of the pyrolysis cleaning cycle, when the catalyst 4 is not yet activated (corresponding to the first part A1i-c, A2i- c of the first phase A1, A2 of the pyrolysis cleaning cycle) are limited.

In addition, when the pyrolysis cleaning cycle is carried out following a cooking cycle, the extraction of the fumes produced by the heated greases during the firing cycle is also limited.

In a first embodiment, during the first portion A1i-c, A2i-c of the first phase A1, A2 of the pyrolysis cleaning cycle, the exhaust fan 6 operates at a first speed of rotation corresponding to the speed of rotation. minimum rotation, and in the second part A1c-p, A2c-p of the first phase A1, A2 of the pyrolysis cleaning cycle, the Exhaust fan 6 operates at a second rotation speed which is higher than the minimum rotational speed.

In a second embodiment, the rotation speed of the extraction fan 6 increases gradually and in proportion to the increase in the temperature of the cavity 2 from the initial temperature T _i to the pyrolysis temperature T _p .

For example, the speed of rotation of the exhaust fan 6 may increase stepwise or linearly.

In one embodiment, the speed of rotation of the exhaust fan 6 has a minimum value when the temperature is below a predefined temperature, for example of a value substantially equal to 200 ° C.

Note that the exhaust fan 6 must operate at a minimum speed to ensure its cooling function.

Then, the rotational speed can increase linearly as the temperature increases between the first preset temperature and the pyrolysis temperature T _p (about 500 ° C).

By way of non-limiting example, when the temperature of the cavity 2 is 200 ° C, the rotation speed of the exhaust fan is 45% of its maximum rotation speed and increases linearly until the cavity 2 has a temperature substantially lower than the pyrolysis temperature T _p , for example 494 ° C, the rotational speed is then 76% of its maximum rotational speed.

Then, when the temperature of the cavity is substantially equal to the pyrolysis temperature T _p , for example 495 ° C, the rotation speed of the exhaust fan 6 operates at its maximum rotational speed.

One embodiment of the pyrolysis cleaning process implemented in a baking oven 1 as described above, will be described with reference to the figure 3 .

For the implementation of the pyrolysis cleaning method, the baking oven 1 further comprises means for verifying the prior implementation of a cooking cycle and comparison means (not shown in the figures) to compare the initial temperature T _i of the cavity 2 to the predetermined temperature. In particular, the means for verifying the prior implementation of a cooking cycle comprise comparison means (not shown) for comparing a cooking temperature T _u of the pre-cooking cycle with a predetermined cooking temperature.

The firing temperature T _u predetermined has for example a value of 140 ° C.

This value of 140 ° C corresponds to a minimum temperature of the walls 2a, 2b, 2c of the muffle and could of course have other values.

The cooking oven 1 further comprises storage means in which the cooking temperature T _u in a cooking cycle is stored.

The storage temperature T _u stored can be the set temperature of the cooking cycle.

Alternatively, the cooking temperature stored _u T may be the temperature measured during the cooking cycle.

In addition, the means for verifying the prior implementation of a cooking cycle include means for determining the cooking time and means for determining the period of time elapsed between the end of a cooking cycle and the beginning of a pyrolysis cleaning cycle, as well as means for comparing the cooking time with a predetermined cooking time and means for comparing said determined period of time with a predetermined period of time.

The means for comparing temperatures, determining time periods, determining the cooking time and storing data such as temperatures or times, are known to those skilled in the art and do not need to be described here. in detail.

Returning to the heating means, they are configured so that the temperature of the cavity 2 follows in time t a temperature curve temp1, temp2. Thus, the temperature rise of the cavity 2 is implemented according to said temperature curve.

As indicated above, the heating means comprise in particular the high resistance 7a, the low resistance 7b and the stirring fan 8.

In one embodiment, when the initial temperature T _i is greater than or substantially equal to a predetermined temperature (in the example shown in FIG. figure 2 , the initial temperature T _i has a value of 160 °) and that the pyrolysis cleaning is carried out after a firing cycle, the heating means 7a, 7b, 8 are controlled in operation so that the temperature in the cavity 2 increases in time t according to the second temp2 temperature curve.

In an exemplary embodiment, during the first portion A2i-c of the first phase A2, only the high resistance 7a is fed at 83% of its maximum power (here 1750 watts). During the second portion A2c-p of the first phase A2, the high resistance 7a is powered at full power, that is to say at 100% of its power (2100 watts in this example), the low resistance 7b is fed at 80% of its power (here 960 watts) and the mixing fan 8 is activated.

During the second phase B2 of the pyrolysis cleaning cycle, the control means managing the operation of the furnace control the maintenance of the temperature of the cavity 2 at the pyrolysis temperature T _p (for example 492 °).

When a user controls a pyrolysis cleaning cycle and the initial temperature T _i of the cavity 2 is lower than the predetermined temperature, regardless of whether a cooking cycle has been previously implemented or not, the means of heating 7a, 7b, 8 are controlled in operation so that the temperature of the cavity 2 increases in time t according to the first temperature curve temp1. Thus, according to one embodiment, the heating means 7a, 7b, 8 are operated in the following manner.

During the first part at A1 ic of the first phase A1 of the pyrolysis cleaning cycle, that is to say between the ambient temperature and the activation temperature T _c of catalyst 4, the high resistance 7a is fed at 83% of its maximum power (here 1750 watts).

In an exemplary embodiment, the high resistance 7a is activated at 100% of its maximum power (for example 2100 watts) during a first predefined period and then deactivated for a second predefined period the first predefined period has a value of 50 seconds and the second predefined period has a value of 10 seconds. Thus, the high resistance 7a is activated periodically every 50 seconds over 60 seconds, which allows an average power supply at 83% of its maximum power.

The second portion A1c-p of the first phase A1 of the pyrolysis cleaning cycle is divided into three partial phases.

During a first partial phase between the activation temperature T _c of the catalyst 4 and an intermediate temperature, being for example here 420 ° C, the high resistance 7a functions, as for the first part A1ic of the first phase A1, to 83% of its maximum power and the low resistance 7b operates at 33% of its maximum power, for example by operating at full power periodically for 20 seconds over 60 seconds.

During a second partial phase starting at the intermediate temperature, being here 420 ° C and up to a second intermediate temperature, here being 475 ° C, the high resistance 7a is activated at 80%, for example by feeding it at full power periodically for 48 seconds on 60 seconds and the low resistance 7b is activated at full power (here 1200 watts)

During a third partial phase ranging from the second intermediate temperature, here being 475 ° C., at the pyrolysis temperature T _p , being here 492 ° C., the high resistance 7a is put into operation at full power, the low resistance 7b is operated at full power periodically for 48 seconds for 60 seconds (80% of its maximum power), and the stirring fan 8 is activated.

Finally, as in the case where the rise in temperature follows the second temp2 temperature curve, once the temperature of the cavity 2 has reached the pyrolysis temperature T _p , the control means managing the operation of the cooking oven 1 control the maintenance of the temperature of the cavity 2 at the pyrolysis temperature T _p , for example at 492 ° C.

Of course, the predefined periods of activation of the heating means 7a, 7b, 8, as well as the heating powers may be different in order to be able to reproduce the temperature curves temp1, temp2.

The figure 3 represents an embodiment of a pyrolysis cleaning method according to the invention.

Indeed, in order to benefit from the thermal inertia of the muffle after a firing cycle, it is necessary that the pre-firing cycle has been performed.

It should be noted that the steps and the order of implementation of the steps represented on the figure 3 can vary. In addition, some of the steps are optional, the pyrolysis cleaning process being implemented according to several embodiments.

The pyrolysis cleaning process carried out in a cooking appliance 1, such as a cooking oven such as that shown in FIG. figure 1 , comprises a step of verifying the prior implementation of a cooking cycle E1.

The pyrolysis cleaning process further comprises a comparison step E2 of the initial temperature T _i of the cavity 2 with a predetermined temperature.

In one embodiment, the predetermined temperature has a value of 100 ° C.

This value of 100 ° C has been determined empirically for the temperature rise to benefit from the thermal inertia of the muffle, and may, of course, have other different values.

When the initial temperature T _i is lower than the predetermined temperature, the rise in temperature is carried out according to the first temp1 temperature curve .

For example, when the initial temperature T _i is substantially equal to the ambient temperature, the rise in temperature over time is implemented according to the first temp1 temperature curve .

When the initial temperature T _i is greater than or substantially equal to a predetermined temperature and a preliminary cooking cycle has been implemented (E1), the rise in temperature over time is implemented according to the second temp2 temperature curve. .

In the embodiment described, the verification E1 of the prior implementation of a cooking cycle comprises a comparison step E3 of a cooking temperature T _u with a predetermined cooking temperature. This cooking temperature T _u corresponds to the baking cycle cooking temperature prior to the pyrolysis cleaning cycle.

The cooking temperature T _u may, for example, be set by a user of the baking oven 1 by means of a man-machine interface comprising control members and displays or may be automatically defined by a calculator in a specific cooking mode. .

The predetermined cooking temperature has, for example, a value of 140 ° C.

This value of 140 ° C corresponds to a minimum temperature of the walls 2a, 2b, 2c of the muffle and could of course have other values.

When the cooking temperature T _u is lower than the predetermined cooking temperature, the rise in temperature over time is implemented according to the first temperature curve temp1.

It should be noted that in this case, the temperature of the cavity 2 does not have a value sufficient for the temperature rise during the pyrolysis cleaning cycle to benefit from a thermal inertia.

On the contrary, when the cooking temperature T _u is greater than or substantially equal to the predetermined cooking temperature and the initial temperature is greater than or equal to the predetermined temperature, the rise in temperature over time is implemented according to the second temp2 temperature curve.

In the embodiment described, the verification E1 of the prior implementation of a cooking cycle comprises a step of determining the cooking time of the cooking cycle implemented prior to the pyrolysis cleaning cycle, as well as a comparison step E4 of the determined cooking time with a predetermined cooking time t _c .

When the cooking time is greater than or substantially equal to the predetermined cooking time t _c , the rise in temperature is implemented according to the second temp2 temperature curve.

When a cooking cycle is implemented prior to the pyrolysis cleaning cycle, the cooking temperature T _u is at least 140 ° C.

Thus, in another embodiment, the determination of the cooking time is equivalent to determining the time during which the cooking temperature T _u is greater than or substantially equal to the predetermined cooking temperature (in this case 140 ° C.).

On the contrary, when the cooking time is less than the predetermined cooking time t _c , the temperature is implemented according to the first temp1 temperature curve .

For example, the predetermined cooking time t _c is 25 min. The cooking time was determined empirically so that the cavity 2 of the baking oven 1 operated at a baking temperature T _u of at least 140 ° C has thermal inertia when the rise in temperature follows the second curve. temp2 temperature .

In an advantageous embodiment of the invention, the predetermined cooking time t _c may be composed of several partial cooking times associated with different cooking cycles carried out for a duration less than the predetermined cooking time t _c .

In order for the partial cooking times to form a cooking time, the temperature of the cavity 2 between cooking cycles must not fall below the predetermined temperature (here of 100 ° C.).

For example, when several cooking cycles are used, and each cooking cycle has a duration of 15 minutes, these cooking times of 15 minutes form a single cooking time when the temperature of the cavity 2 is greater than the predetermined temperature during and between the implementation of the three baking cycles.

It will be noted that during the verification step E1, it is verified that a cooking cycle has been carried out at a minimum cooking temperature and / or during a minimum cooking time in order to benefit from the thermal inertia of the oven. muffle.

It will be noted that the comparison steps E2, E3, E4 can be implemented in the aforementioned order, or in any other order.

Thus, the cleaning method can be implemented according to several embodiments.

According to one embodiment, the pyrolytic cleaning process comprises the step of comparing an initial temperature T _i with the predetermined temperature E2 and E3 the step of comparing the cooking temperature T _u with the cooking temperature predetermined.

According to yet another embodiment, it comprises the comparison step E2 of the initial temperature T _i with the predetermined temperature, the comparison step E3 of the cooking temperature T _u with the predetermined cooking temperature, and the comparison step E4 of the cooking time at the predetermined cooking time t _c .

According to yet another embodiment, it comprises the comparison step E2 of the initial temperature T _i with the predetermined temperature, and the comparison step E4 of the cooking time with the predetermined cooking time t _c .

The pyrolysis cleaning process may further comprise a step of determining (not shown) the period of time elapsed between the end of a firing cycle and the beginning of a pyrolysis cleaning cycle. and a step of comparing this determined elapsed time period with a predetermined period of time.

When the determined elapsed period of time is less than a predetermined period, the rise in temperature is carried out according to the second temp2 temperature curve.

On the contrary, when the elapsed period of time is greater than the predetermined period of time, the rise in temperature is implemented according to the first temp1 temperature curve .

Indeed, in order to benefit from the thermal inertia of the muffle, it is necessary that the pyrolysis cleaning cycle be performed shortly after the baking cycle.

In summary, when the initial temperature T _i of the cavity is lower than the predetermined temperature, the temperature rise in time is carried out by first temp1 temperature curve.

In particular, when a cooking cycle has been previously implemented, but the initial temperature T _i of the cavity is lower than the predetermined temperature, the temperature rise in time is carried out by first temp1 temperature curve .

When the pyrolysis cleaning process comprises the step of checking the cooking temperature T _u with the predetermined cooking temperature, when the cooking temperature T _u is lower than the predetermined cooking temperature, the rise in temperature over time is implemented according to the first temp1 temperature curve .

The pyrolysis cleaning process may further include a verification of the cooking time, as well as the period of time between the end of a cooking cycle and the beginning of a pyrolysis cleaning cycle.

It should be noted that the cooking temperature in a cooking cycle is at least 140 ° C. Thus, the cooking time is equivalent to the cooking time during which the cooking temperature T _u is greater than or substantially equal to the predetermined cooking temperature.

Thus, when the cooking time of a cooking cycle is less than a predetermined cooking time t _c , or the period of time elapsed between the end of the firing cycle and the beginning of the pyrolysis cleaning cycle is less than a predetermined period of time, the rise in temperature is implemented according to the first temp1 temperature curve .

When a firing cycle has been implemented and the initial temperature T _i of the cavity 2 is greater than or substantially equal to the predetermined temperature, the firing temperature T _u is greater than or substantially equal to the predetermined firing temperature. and / or that the cooking time is greater than or substantially equal to the predetermined cooking time t _c, and optionally the time period elapsed between the end of the cooking cycle and the beginning of the cleaning cycle is greater than or substantially equal to a predetermined period, the rise in temperature over time is implemented according to the second temp2 temperature curve.

In other words, when a firing cycle has been implemented with a temperature greater than the predetermined firing temperature and / or during a firing time greater than a firing time in effect according to the second temp2 temperature curve.

Of course, in some embodiments, some of the above steps are not implemented.

Claims (20)

Cooking apparatus having a cavity (2) and means for carrying out a pyrolysis cleaning cycle in which the temperature of the cavity increases from an initial temperature (T _i ) to a pyrolysis temperature (T _p ), the rise in temperature over time being carried out according to a first temperature curve ( temp1 ) , said cooking apparatus (1) being characterized in that said means for implementing a pyrolysis cycle implement said rise in temperature over time according to said first temperature curve ( temp1 ) when the initial temperature (T _i ) is lower than a predetermined temperature and according to a second temperature curve ( temp2 ) when a cooking cycle has been previously set and said initial temperature (T _i ) is greater than or substantially equal to said predetermined temperature, said second temperature curve (temp2) comprising at least minus a substantially linear portion ( temp2 (1) ) corresponding to a temperature interval (I _T ), said portion ( temp2 (1) ) having a slope (α2) greater than the value of the slope (α1) of a portion ( temp1 (1) ) of said first temperature curve ( temp1 ) corresponding to said temperature range (I _T ). Cooking apparatus according to claim 1, characterized in that it comprises a catalyst (4) for neutralizing the fumes produced in the cavity (2) during the pyrolysis cleaning cycle and in that said pyrolysis cleaning cycle comprises a first part (A1i-c, A2i-c) in which the temperature of the cavity (2) increases from the initial temperature (T _i ) to an activation temperature (T _c ) of said catalyst (4) and a second part (A1c-p, A2c-p) in which the temperature increases from said activation temperature (T _c ) of the catalyst (4) to said pyrolysis temperature (T _p ), said temperature range (I _T ) substantially corresponding to the second part (A1c-p, A2c-p) of the pyrolysis cleaning cycle. Cooking appliance according to one of claims 1 or 2, characterized in that it comprises an extraction fan (6) for extracting the fumes produced in the cavity (2) during the pyrolysis cleaning cycle, and control means of said exhaust fan (6) configured to operatively control said exhaust fan (6) at a rotational speed, said speed rotation of said exhaust fan (6) being a function of the temperature of said cavity (2). Cooking appliance according to one of Claims 1 to 3, characterized in that the means for carrying out a pyrolysis cleaning cycle comprise heating means (7a, 7b, 8) configured in such a way that the temperature of the cavity (2) increases as the first temperature curve (temp1) or according to the second temperature curve (time2). Cooking apparatus according to one of claims 1 to 4, characterized in that said predetermined temperature is substantially equal to 100 ° C. Cooking appliance according to one of claims 1 to 5, characterized in that it is a cooking oven. Pyrolysis cleaning method for a cooking apparatus (1) having a cavity (2) and implementing a pyrolysis cleaning cycle in which the temperature of the cavity increases from an initial temperature (T _i ) to a temperature pyrolysis (T _p ), said temperature rise in time being implemented according to a first temperature curve ( temp1 ) , said pyrolysis cleaning process being characterized in that said temperature rise in time is implemented according to said first temperature curve ( temp1 ) when said initial temperature (T _i ) is lower than a predetermined temperature and according to a second temperature curve ( temp2 ) when a cooking cycle has been previously implemented and said initial temperature ( T _i ) is greater than or substantially equal to said predetermined temperature, said second temperature curve (temp2) comprising a at least one portion ( temp2 (1) ) substantially linear corresponding to a temperature range (I _T ), said portion ( temp2 (1) ) having a slope (α2) greater than the value value of the slope (α1) of a portion ( temp1 (1) ) of said first temperature curve ( temp1 ) corresponding to said temperature range (I _T ). Pyrolysis cleaning method according to claim 7, characterized in that said pyrolysis cleaning cycle comprises a first part (A1i-c, A2i-c) in which the temperature of the cavity (2) increases from the initial temperature ( T _i ) up to an activation temperature (T _c ) of a catalyst (4) neutralizing the fumes produced in the cavity (2) during the pyrolysis cleaning cycle, and a second part (A1c-p, A2c -p) in which the temperature increases from said activation temperature (T _c ) of the catalyst (4) to said pyrolysis temperature (T _p ), said temperature interval substantially corresponding to the second portion (A1 cp, A2c -p) of the pyrolysis cleaning cycle. Pyrolysis cleaning method according to one of claims 7 or 8, characterized in that it comprises the control of an exhaust fan (6) of the fumes produced in the cavity (2) during the cleaning cycle by pyrolysis, at a rotational speed depending on the temperature of the cavity (2). Pyrolysis cleaning method according to claim 9, characterized in that the control of the exhaust fan (6) comprises the operation of said exhaust fan (6) at a minimum speed of rotation when said cavity (2) is at said initial temperature (T _i ), the rotational speed of said exhaust fan (6) increasing when the temperature of said cavity (2) increases. Pyrolysis cleaning method according to one of claims 7 to 10, characterized in that it comprises the control in operation of the heating means for a predetermined period of time and at a predetermined power so that the temperature of the the cavity (2) increases according to the first temperature curve ( temp1 ) or the second temperature curve ( temp2 ) . Pyrolysis cleaning method according to one of Claims 7 to 11, characterized in that it comprises the verification (E1) of the prior implementation of a firing cycle and comparison (E2) of said initial temperature (T _i ) to a predetermined temperature. Pyrolysis cleaning method according to one of claims 7 to 12, characterized in that said predetermined temperature is substantially equal to 100 ° C. Pyrolysis cleaning method according to one of claims 7 to 13, characterized in that it comprises the determination of a period of time elapsed between the end of said firing cycle and the beginning of said pyrolysis cleaning cycle, the temperature rise in time being implemented according to the second temperature curve ( temp2 ) when said determined period of time is less than a predetermined period. Pyrolysis cleaning method according to one of claims 12 to 14, characterized in that said verification of the prior implementation of a cooking cycle comprises the comparison (E3) of a cooking temperature (T _u ) during said pre-cooking cycle at a predetermined cooking temperature. Pyrolysis cleaning method according to claim 15, characterized in that the rise in temperature over time is carried out according to said second temperature curve ( temp2 ) , when the cooking temperature (T _u ) is greater or substantially equal to at the predetermined cooking temperature. Pyrolysis cleaning method according to one of claims 12 to 16, characterized in that said verification of the prior implementation of a cooking cycle comprises determining the cooking time (E4) of said cooking cycle, and comparing the determined cooking time with a predetermined cooking time. Pyrolysis cleaning method according to claim 17, characterized in that the rise in temperature over time is carried out according to said second temperature curve ( temp2 ) when said cooking time is greater than or substantially equal to the predetermined cooking time . Pyrolysis cleaning method according to one of claims 15 to 18, characterized in that said predetermined cooking temperature is substantially equal to 140 °. Pyrolysis cleaning method according to one of Claims 15 to 18, characterized in that several baking cycles have been implemented beforehand, each baking cycle having an associated partial baking time, said baking times corresponding to the sum of said plurality of partial cooking times when the temperature of the cavity (2) is greater than the predetermined temperature between the implementation of the baking cycles.

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