EP2930431B1 - Method for carrying out a pyrolysis cleaning procedure - Google Patents

Description

The present invention relates to a method for carrying out a pyrolysis cleaning process according to the preamble of claim 1.

In modern cooking appliances with a cooking chamber for preparing food, for example in ovens, a user is often provided for easy cleaning of the cooking chamber a pyrolytic cleaning available.

In such a pyrolysis process, the cooking chamber and the accessories located therein are heated to a very high temperature, usually above 400 ° C. Due to the high heat, the contaminants present in the cooking chamber are burnt to fine ash, which then simply has to be wiped out of the cooking chamber by a user.

The known pyrolysis usually work satisfactorily. However, some stubborn soiling is not or not completely burned by such a pyrolysis process, so that a complicated manual cleaning by the user may be necessary.

Such difficult soiling are z. B. Laking of oil, as they can occur at temperatures between about 250 ° C and 350 ° C. By the oil oiling creates a firmly adhering layer of dirt, which may be only partially eliminated by a conventional pyrolysis. Due to the firm adhesion of the laking on the cooking space walls, the final cleaning by hand is particularly difficult.

From the US 6,417,493 is a self-cleaning system for a convection cooking appliance is known in which then take place after heating to a maximum temperature and a holding phase, a cooling phase and a reheating phase. The temperature difference between the maximum temperature and the temperature of the cooling phase at 60 ° F, which corresponds to 33.3 ° C. At such low temperature differences, a different thermal expansion compared to any remaining dirt or laking is not given, inasmuch as the dissolution of such contamination is not improved.

From the US 5,571,433 a temperature control system for a self-cleaning oven is known in which after reaching the maximum temperature, a cycle takes place with a change between a maximum and a minimum temperature. The temperature difference is 200 ° F (111.11 ° C), the minimum temperature is 675 ° F (353.9 ° C).

The DE 21 66 227 A1 discloses an oven with a pyrolysis-cleaning function, in which a two-stage heating takes place.

In a Pyrolysereinigungsvorgang according to DE 10 2006 041767 B3 an oxygen sensor is used for fire detection.

It is the object of the present invention to provide a method for carrying out a pyrolysis-cleaning process, which ensures a better cleaning effect and in particular causes a complete cleaning.

This object is achieved by a method having the features of claim 1. Preferred developments of the invention are the subject of the dependent claims. Further advantages and features of the invention will become apparent from the embodiments.

The inventive method is suitable for performing a Pyrolysereinigungsvorgangs in a cooking appliance. In this case, the cooking appliance comprises at least one cooking chamber which can be heated by means of at least one heating device and at least one control device. The cooking chamber is limited by at least one Garraummuffel and at least one cooking chamber door, wherein the cooking chamber for cleaning the Garraummuffel and the cooking chamber facing side of the cooking chamber door is heated in at least one heating phase to a predetermined temperature. In at least one subsequent hold phase, this predetermined temperature is substantially maintained. Subsequently, the cooking chamber is cooled down again in a cooling phase. In this case, at least one further heating phase and at least one further cooling phase are then run through.

The heating phases, the holding phases and / or the cooling phases are set and run automatically by the control device. Such a program automatic allows a particularly thorough cleaning of the cooking chamber, without a user having to control the cooking appliance all the time in order to manually adjust any subsequent phases.

Between at least one cooling phase and the next heating phase, a waiting phase is passed. Such a waiting phase is used in particular for relaxation of the materials of the Garraummuffel and the cooking chamber door and the dirt or varnish. It can thereby be achieved that any laking which may be present during the renewed heating of the cooking chamber is more easily peeled off from the cooking space, from the side of the cooking chamber door facing the cooking space and / or from accessories introduced into the cooking space.

According to the invention, the temperature of the cooking chamber in the cooling phase at least at 200 ° C to room temperature, preferably at 100 ° C to room temperature, and particularly preferred cooled down to 50 ° C to room temperature. Such a cooling of the cooking chamber ensures that any remaining stubborn dirt such. B. a laking dissolves or flakes off due to the different thermal expansion compared to the Garraummuffel or the cooking chamber door. In this case, a temperature of about 20 ° C. is preferably to be understood as room temperature. In particular, room temperature is also understood to mean a normal temperature of a room which is normal at the installation site of the cooking appliance. Room temperature may, however, preferably also be understood to mean the temperature at which no appreciable cooling takes place more per period of time.

According to the invention, the method can be used in particular in cooking appliances, which have a cooking chamber, which is heated with a thermal heat source, for. B. in ovens or combi appliances with an oven.

The heating device preferably comprises one or more heating sources, which can heat the cooking chamber, for example in a circulating air operation, by means of top and bottom heat, in a hot air operation, in a microwave operation and / or in a gas operation

The control device is preferably suitable and designed so that the temperature and / or the operating mode for heating the cooking chamber can be adjusted. It may be provided in particular that the temperature and / or the operating mode manually entered by a user or that an automatic specification of the temperature and / or the mode is possible.

The method according to the invention offers many advantages. A considerable advantage is that a particularly thorough and preferably substantially complete cleaning of the Garraummuffel and the cooking chamber facing side of the cooking chamber door is achieved in particular by the multiple passing through heating phases and cooling phases.

By well-known pyrolysis processes with only one heating phase, a holding phase and a cooling phase of the oven and in the oven befindliches accessories is often already satisfactorily cleaned, however, it may in normal operation and also during the pyrolysis to a so-called laking of burned food residues and especially of oil come. However, such laking may not be completely burned to ashes during the purging process in a single pyrolysis operation, so that subsequent manual cleaning of the areas of the cooking chamber and the cooking chamber door with laking may be necessary. The removal of such laking residue by hand, however, may be quite expensive and may also affect the ease of use for the user.

By carrying out the pyrolysis-cleaning process according to the invention, the cooking chamber is first heated to a predetermined temperature as in conventional pyrolysis operations, on which the cooking chamber is held for a predetermined time. As a result, a mostly already predominant cleaning of the cooking chamber is achieved. Subsequently, the cooking chamber is cooled again.

The commonly used within a cooking chamber materials such. As metal, enamel or glass have a different thermal expansion compared to any remaining dirt or laking. Due to the different material expansions it then comes through the alternating heating and cooling to a detachment or even spalling of the laking from the Garraummuffel, the cooking chamber facing side of the cooking chamber or introduced into the oven accessories.

Subsequently, the cooking chamber is heated in at least one further heating phase to or a predetermined pyrolysis temperature, whereby the remaining contaminants, especially in the areas of laking can be completely burned to ashes. Depending on the degree of soiling of the cooking chamber further heating phases and cooling phases may be necessary to achieve a complete and thus satisfactory cleaning of the cooking chamber.

Overall, a pyrolysis cleaning process is provided by the method according to the invention, which allows a substantially complete cleaning of the cooking chamber, without a subsequent cleaning by hand is required.

Depending on the degree of contamination of the cooking chamber is preferably at least pass through another holding phase. In this case, this holding phase is provided in particular between a further heating phase and a further cooling phase. By passing through another holding phase in the cleaning process, even heavy soiling, which has easily or completely dissolved in the cooling phase of the previous cleaning cycle, can be effectively burned to fine ash.

In preferred developments, the individual heating phases and / or the individual holding phases and / or the individual cooling phases have different lengths. If one or more waiting phases are provided in a pyrolysis cleaning process, these waiting phases in individual cleaning cycles may also have different time periods.

In this case, the individual heating phases and / or the individual holding phases and / or the individual cooling phases are particularly preferably shorter with increasing number of passes or cleaning cycles. Thus it can be achieved inter alia that the inventive Pyrolysereinigungsvorgang is kept as short as possible and also not unnecessarily much energy is consumed. By a first longer cleaning process with z. B. a longer holding phase at the predetermined temperature can usually be achieved already a vast cleaning of the cooking chamber, creating only stubborn dirt such. B. a laking in the further cleaning cycles must be removed or burned. As a result of the cooling of the cooking chamber between the individual cleaning passes, however, the laking is usually already dissolved, so that the next or the next cleaning passages no longer have to be provided as long as the preceding or preceding cleaning passes.

In order to achieve a particularly satisfactory cleaning of the cooking chamber and in particular a substantially complete burning of contaminants in the oven, the predetermined temperature of at least one heating phase is between 350 ° C and 550 ° C, preferably between 400 ° C and 500 ° C and more preferably between 430 ° C and 470 ° C. By heating the cooking chamber to such a predetermined temperature in the heating phase and in particular by keeping the oven temperature at such a predetermined temperature in the holding phase, a satisfactory cleaning or the burning of contaminants can be ensured.

In particular, in order to minimize the energy consumption of the pyrolysis cleaning process according to the invention, the predetermined temperature of at least one heating phase in advantageous embodiments may be different from the predetermined temperature of at least one further heating phase. It is particularly preferred that the predetermined temperature decreases with increasing number of passes of the individual phases.

In expedient refinements, at least one cooling phase can be accelerated from the time when an uncritical temperature is reached by aeration of the cooking chamber. In this case, an uncritical temperature is to be understood as meaning, in particular, a temperature at which, as a rule, no risk of injury to a user is to be expected. So z. B. a temperature of less than 100 ° C and in particular of less than 80 ° C are chosen meaningful. By supporting or accelerating the cooling process, at least two positive affects can be achieved. On the one hand, the duration of the pyrolysis cleaning process is shortened. On the other hand may be achieved by the faster cooling even more effective peeling or flaking off of laking, since the different thermal expansions of the laking and the materials in and on the cooking chamber with faster temperature fluctuations affect even more significant.

In order to accelerate the cooling process, preferably the cooking chamber door can be opened in the cooling phase from an uncritical temperature. The opening of the oven door can be z. B. done manually. Then the possibility of accelerating the cooling process is expediently a user z. B. displayed on a display or it can also be issued a warning sound. However, it is also possible that the door is automatically opened when it reaches a non-critical temperature. This can then z. B. sensor-controlled in conjunction with an automatically opening or motorized door. Under the opening of the cooking chamber is understood in particular according to the invention that the door is opened at least one gap wide, so that hot air can escape from the cooking chamber. But it can also be provided on the Garraummuffel or the cooking chamber door other ventilation openings, which are used for accelerated cooling of the cooking chamber.

In an automatic program, the number of heating phases to be passed and / or holding phases and / or cooling phases can then be specified as a function of the contamination of the cooking chamber. In advantageous developments, the individual lengths and / or the predetermined temperatures can then also be predetermined and / or set by a user before starting the program. So z. B. be preprogrammed in the device several programs that can be selected depending on the degree of contamination of a user. Then, for example, a light pollution program, a normal pollution program, and a heavy pollution program may be set. These different programs then advantageously differ in the number of individual phases, in the length of the phases and / or in the predetermined predetermined temperatures. In addition, a manually programmable or adjustable program can also be provided.

The cooking appliance according to the invention comprises at least one cooking space which can be heated by means of at least one heating device and at least one control device. The cooking chamber is limited by at least one Garraummuffel and at least one cooking chamber door. The control device is suitable and designed to carry out the method described above for carrying out a pyrolysis cleaning process.

The cooking appliance according to the invention also offers the advantages already outlined above. In particular, a user can be made available a cooking appliance by carrying out the pyrolysis cleaning process according to the invention, in which a substantially completely automated cleaning of the cooking chamber takes place without the need for a laborious post-cleaning by hand.

Further advantages and features of the present invention will become apparent from the embodiments, which are explained below with reference to the accompanying figures.

Figur 1

eine rein schematische Darstellung eines erfindungsgemäßen Gargerätes in einer perspektivischen Ansicht;

Figur 2

ein rein schematisches Ablaufschema eines erfindungsgemäßen Verfahrens zum Durchführen eines Pyrolyse-Reinigungsvorgangs;

Figur 3

ein weiteres rein schematisches Ablaufschema eines erfindungsgemäßen Verfahrens zum Durchführen eines Pyrolyse-Reinigungsvorgangs; und

Figur 4

ein anderes rein schematisches Ablaufschema eines erfindungsgemäßen Verfahrens zum Durchführen eines Pyrolyse-Reinigungsvorgangs.

In the figures show:

FIG. 1

a purely schematic representation of a cooking appliance according to the invention in a perspective view;

FIG. 2

a purely schematic flow diagram of a method according to the invention for performing a pyrolysis cleaning process;

FIG. 3

a further purely schematic flow diagram of a method according to the invention for performing a pyrolysis cleaning operation; and

FIG. 4

another purely schematic flow diagram of a method according to the invention for performing a pyrolysis-cleaning operation.

In FIG. 1 one sees the purely schematic representation of a cooking device 1 according to the invention in a perspective view, which is formed in the embodiment shown here as a baking oven 100. The cooking appliance 1 comprises a cooking chamber 3, which has a cooking chamber opening 10 for loading the cooking chamber 3, which can be closed by means of a cooking chamber door 6.

Above the cooking chamber, a control panel 11 is arranged, behind which the control device 4 is provided, which in FIG. 1 is shown schematically by a dashed box. The control panel 11 includes a display device 12 and a plurality of controls 13 for operating the cooking appliance 1. This display device 12 in the control panel 11 is executed as a display 14, on which the user various information on the status of the cooking appliance 1 and set parameters are provided.

The cooking chamber 3 is limited by a Garraummuffel 5 and the cooking chamber 6. When the cooking chamber door 6 open accessories such. B. a baking sheet or a rust in the cooking chamber 3 are introduced and it can be adjusted food in the cooking chamber 3, which are cooked by means of the heater 2.

The heater 2 is provided above the cooking chamber 3 and covered in the embodiment shown here by a housing panel 15. The heater comprises a plurality of heat sources 16, which heat the cooking chamber 3 in a recirculation mode and by means of top and bottom heat. Other heating sources 16, the cooking chamber in a hot air operation, in can heat a microwave operation and / or in a gas operation, can be used meaningfully in other embodiments.

The cooking appliance 1 according to the invention is particularly suitable for carrying out a pyrolysis cleaning process, as will be described below. When preparing food in the cooking chamber 3, it may, for example, by spilling food and / or alone by the greasy fumes to more or less severe soiling of Garraummuffel 5 and the cooking chamber 3 facing side 7 of the cooking chamber 6 come.

In order to eliminate such contamination substantially automatically, a pyrolysis cleaning process can be carried out in the cooking appliance 1, the baked dirt residues on the Garraummuffel 5 or on the cooking chamber 3 facing side 7 of the cooking chamber door 6 burns substantially completely to fine ash. In order to ensure a particularly thorough cleaning of the cooking chamber, the control device 4 of the cooking appliance 1 according to the invention is suitable and designed to carry out a method for carrying out a pyrolysis cleaning process according to the invention.

In FIG. 2 a flow chart of a method according to the invention for carrying out a pyrolysis-cleaning process according to the invention is shown purely schematically. The temperature profile of the pyrolysis process is plotted over time. As in FIG. 2 can be seen, the cooking chamber 3 is heated in a heating phase a1 to a predetermined temperature 8, which is 450 ° C in the embodiment shown here. In this case, the pyrolysis process is started in the example shown here by a cooking chamber 3 cooled to room temperature. However, it is also possible that the pyrolysis is started directly after a cooking process, so that the heating not from room temperature, but from the previously pre-use oven temperature, eg. B. 200 ° C, is started.

After reaching the predetermined temperature 8, the cooking chamber 3 is held in a first holding phase b1 at the predetermined temperature. In the first heating phase a, a1 and the first holding phase b, b1 a large part of the dirt and possibly even the complete contamination of the cooking chamber 3 is already burned to fine ash. Then, the pyrolysis process after the first cooling c, c1 could possibly be terminated, since the cooking chamber 3 is completely cleaned.

The soils burnt to fine ashes can then simply be swept by the user from the cooking chamber 3 or wiped with a damp cloth.

However, the cooking chamber 3 is heavily soiled and in particular when baked oil on the Garraummuffel 5 or on the cooking chamber 3 facing side 7 of the cooking chamber door 6 is passing through a heating phase a and a holding phase b may not be sufficient to eliminate the contamination of the cooking chamber 3 completely. Oil lacks at about 250 ° C to 350 ° C, creating a particularly stubborn dirt layer that can often not or not completely eliminated by a simple pyrolysis. Then, a complex re-cleaning by hand by the user is often necessary, which, however, would like to avoid, in particular for reasons of comfort.

In order to achieve a complete cleaning of the cooking chamber and, in particular, to achieve a complete burning of soiling, at least one second heating phase a2 and at least one second cooling phase c2 are carried out in the method according to the invention. In the in FIG. 2 In the example shown, the first pyrolysis operation carried out is followed by a second heating phase a2, a second holding phase b2, a second cooling phase c2, a third heating phase a3, a third holding phase b3 and a third cooling phase c3.

By the multiple heating to a predetermined temperature, by holding at this temperature and by cooling the cooking chamber 3 between two pyrolysis passes a particularly effective cleaning of the cooking chamber 3 is possible. This results from the fact that any existing laking on the Garraummuffel 5 or the cooking chamber facing side 7 of the cooking chamber 6 solve by the alternating heating and cooling of the cooking chamber 3 or that they even peel off.

The laking or other heavily baked or encrusted soiling namely have a different thermal expansion, as the materials of Garraummuffel 5 and the cooking chamber facing side 7 of the cooking chamber door 6. For the Garraummuffel 5 z. B. often metal 17 or enamel 18 is used, wherein the cooking chamber facing side 7 of the cooking chamber door 6 is often provided by a glass 19. These materials behave differently to the laking or other soiling during heating and cooling, as a result of which these contaminants dissolve or even flake off due to a differential expansion and contraction during heating and during cooling. So can be burned by a first pyrolysis passage already a large part of the pollution. When cooling the Garraummuffel 5 and the cooking chamber door 6 then it comes to a relaxation, a detachment or even a spalling of the remaining dirt.

Then, in a first pass of heating, holding and cooling, a large part of the dirt can be burnt to ashes. Upon cooling, the remaining dirt then dissolves due to the different thermal expansions. In the next cycle of heating, holding and cooling or in another pass then the remaining contaminants can be completely burned, so that a total satisfactory and especially complete cleaning of the cooking chamber 3 is made possible.

In FIG. 3 another scheme of the method according to the invention for performing a pyrolysis-cleaning operation is shown purely schematically. In this case, a heating phase a1 is first started again, in which the cooking chamber 3 is heated to a predetermined temperature 8. In a holding phase b1 a large part of the existing contamination is burned by the high temperature to fine ash. Subsequently, the cooking chamber 3 is cooled down to room temperature RT in a cooling phase c1. Subsequently, in a second heating phase 2 of the cooking chamber 3 is heated to the predetermined temperature, then directly a cooling c2 is again provided, in which the cooking chamber 3 is not cooled to room temperature RT, but only to about 50 ° C. Subsequently, a heating phase a3 is performed again, wherein the predetermined temperature 8 in the heating phase a3 is below the predetermined temperature 8 of the heating phases a1 and a2. The heating phase a3 is followed by a further holding phase b3, after which the cooking chamber 3 is cooled down again to room temperature RT in a cooling phase c3.

Before a last heating phase 4 a waiting phase d3 is provided, which is intended to ensure that the Garraummuffel 5 and the cooking chamber door 6 and the remaining dirt completely relax that they dissolve and in the next heating phase a4 and b4 in the following holding phase completely burned. Subsequently, the cooking appliance is again cooled to room temperature in the cooling phase c4.

FIG. 4 shows a further scheme for a method according to the invention for carrying out a pyrolysis cleaning process. In this scheme, three runs of heating phase a, holding phase b and cooling phase c are provided. In this case, in each heating phase a1, a2, a3 of the cooking chamber 3 is heated to a predetermined temperature 8, which is 450 ° C in this embodiment, too.

The heating phases a are followed by a holding phase b1, b2, b3. Before the heating phases a2 and a3, a cooling phase c1 and c2 is provided, in which the cooking chamber 3 is cooled to about 50.degree.

In order to accelerate the cooling process, the cooling process is accelerated by opening the cooking chamber door 6 upon reaching an uncritical temperature 9, and thus supported. The uncritical temperature 9 is selected in the embodiment shown here at about 80 ° C, so that the risk of injury to a user is excluded in the normal case. To accelerate the cooling process but z. B. also other vents in the Garraummuffel and / or blower can be used. Advantageously, cool or cold air can be blown into the cooking chamber 3 in order to effect a particularly rapid temperature difference.

All exemplary embodiments of the method according to the invention for carrying out a pyrolysis cleaning process shown above can be carried out automatically by the control device 4. In particular, various preset pyrolysis programs can also be stored in the control device 4 by default, which can be activated by a user by pressing a button.

So z. B. different program automatically be provided, which can be selected depending on the severity of contamination of the cooking chamber 3. It is also possible for a user to set and save their own program schemes.

In addition, it can also be set by a user that the cooking chamber is only very slightly contaminated and that only a single pass of heating phase a, holding phase b and cooling phase c should be passed through.

Preferably, the accelerated cooling of the cooking chamber 3 can be implemented in an automatic program. This can z. B. the control device to detect the cooking chamber temperature via a sensor device and when it reaches a non-critical temperature then a preferably motorized cooking chamber door 6 open at least one gap wide.

If no motorized door is provided on the cooking appliance 1, in appropriate embodiments by the control device 4 upon reaching a non-critical temperature 9, a warning message, for example, be issued on the display 14 or it can also be issued a warning tone. On the basis of such a warning, a user can then easily recognize that he should open the cooking chamber door to shorten the pyrolysis process a gap.

LIST OF REFERENCE NUMBERS

1

Cooking appliance

2

heater

3

oven

4

control device

5

Garraummuffel

6

oven door

7

the cooking chamber side facing

8th

predetermined temperature

9

uncritical temperature

10

cooking compartment

11

control panel

12

display

13

operating element

14

display

15

housing panel

16

heating source

17

metal

18

enamel

19

pane

100

oven

a

heating phase

b

holding phase

c

cooling phase

d

waiting phase

a1-ax

heating phase

b1-bx

holding phase

c1-cx

cooling phase

d1-cx

waiting phase

RT

room temperature

Claims (9)

1. Method for carrying out a pyrolytic cleaning process for a cooking appliance (1) comprising at least one cooking chamber (3) that can be heated using at least one heating device (2) and comprising at least one control device (4), the cooking chamber (3) being delimited by at least one cooking chamber muffle (5) and at least one cooking chamber door (6), in which the cooking chamber (3), in order to clean the cooking chamber muffle (5) and the side (7) of the cooking chamber door (6) that faces the cooking chamber (3), being heated to a predetermined temperature (8) in at least one heating phase (a1), being substantially maintained at the predetermined temperature in at least one maintenance phase (b1), and being cooled down again in a cooling phase (c1), and subsequently at least one additional heating phase (a2) and at least one additional cooling phase (c2) being run through, the heating phases (a1-ax), the maintenance phases (b1-bx) and/or the cooling phases (c1-cx) being set and run through automatically by the control device (4),
   characterised in that
   at least one waiting phase (d) is run through between at least one cooling phase (c) and the next heating phase (a), and the temperature in the cooking chamber (3) cools down to at least between 200 °C and room temperature (RT), preferably between 100 °C and room temperature (RT) and particularly preferably between 50 °C and room temperature (RT) during the cooling phase (c1).
2. Method according to claim 1, characterised in that at least one additional maintenance phase (b2) is run through.
3. Method according to either of the preceding claims, characterised in that the individual heating phases (a1-ax) and/or the individual maintenance phases (b1-bx) and/or the individual cooling phases (c1-cx) are of different durations.
4. Method according to the preceding claim, characterised in that the individual heating phases (a1-ax) and/or the individual maintenance phases (b1-bx) and/or the individual cooling phases (c1-cx) become shorter as the number of run-throughs increases.
5. Method according to any of the preceding claims, characterised in that the predetermined temperature (8) of at least one heating phase (a1-ax) is between 350°C and 550°C, preferably between 400 °C and 500 °C and particularly preferably between 430 °C and 470 °C.
6. Method according to any of the preceding claims, characterised in that the predetermined temperature (8) of at least one heating phase (a1-ax) is different from the predetermined temperature of at least one additional heating phase (a1-ax).
7. Method according to any of the preceding claims, characterised in that the cooling phase (c) is accelerated by ventilation of the cooking chamber (3) once an uncritical temperature (9) has been reached.
8. Method according to any of the preceding claims, characterised in that, in order to accelerate the cooling phase (c), the cooking chamber door (6) is opened starting from an uncritical temperature.
9. Method according to the preceding claim, characterised in that the number and/or the duration of the heating phases (a1-ax) and/or maintenance phases (b1-bx) and/or cooling phases (c1-cx) to be run through and/or the predetermined temperature (8) are specified based on the soiling of the cooking chamber (3).

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