EP3058281A2

EP3058281A2 - Method for operating a cooking device, and such a cooking device for performing the method

Info

Publication number: EP3058281A2
Application number: EP14784445.0A
Authority: EP
Inventors: Peter Helm; Henrik PULS; Ralph DEPKE
Original assignee: MKN Maschinenfabrik Kurt Neubauer GmbH and Co KG
Current assignee: MKN Maschinenfabrik Kurt Neubauer GmbH and Co KG
Priority date: 2013-10-14
Filing date: 2014-10-14
Publication date: 2016-08-24
Also published as: WO2015055676A3; US20160258634A1; US10253989B2; WO2015055676A2

Abstract

The invention relates to a method for operating a cooking device (1) in the form of a hot convection oven, a hot-air steamer, or a combi steamer, which has a cooking chamber (6), which can be closed by means of a cooking-chamber door (7), a heating apparatus (31), at least one steaming apparatus (33), at least one flow-generating apparatus, such as a fan (29), at least one temperature sensor (35), which detects the temperature in the cooking chamber (6), and an electronic device controller having a memory unit, in which memory unit cooking programs are stored, which cooking programs comprise cooking processes for specific products to be cooked. The invention is characterized in that, on the basis of a cooking time stored in the memory unit for a certain type of product to be cooked for minimal loading of the cooking chamber from a starting temperature value to a target temperature value, it is determined, by using the detected temperature progression in the cooking chamber, whether and, if applicable, by what amount a time delay until the attainment of the target temperature value results, and in that, on the basis of the detected time delay, the cooking-device controller calculates a cooking-time extension, by which the running cooking-program step is then extended. The invention further relates to a cooking device for performing the method.

Description

Method for operating a cooking appliance and such a cooking appliance for

Implementation of the procedure

The present invention relates to a method of operating a cooking device in the form of a hot-air circulating oven, a combi steamer or a combi steamer, which is able to perform an automatic cooking time adjustment.

Modern cooking appliances in the form of convection ovens, in particular of combi steamer, which can control corresponding cooking steps by means of stored in the control cooking programs include cooking steps, the cooking time is aligned with the loading of a single sheet or insert in the oven. However, the cooking appliances are charged with different amounts of food to be cooked. Thus, half load the half of the sheets or trays with food, whereas when all sheets are occupied or all bays are loaded, there is the full load of the cooking appliance.

The heating power provided by the cooking appliance must be divided according to the number of loaded sheets. This division is relevant in the heating phase at the beginning of the cooking process. The initially cold food lowers the cooking space in optionally preheated to desired temperature cooking chamber. By means of the temperature control, the cooking chamber is brought back to the desired temperature by means of the heating device. Due to the finite heating capacity of the heater, this process is dependent on the load. That is, at higher loadings it takes longer than at low load levels to reach the setpoint temperature. It can be seen that depending on the distribution of the introduced heating energy in the heating phase according to the load, this heating phase takes longer, the greater the load. To compensate for load differences, a core temperature sensor is often used, which measures the temperature in the food itself with one or more temperature sensors. The cooking process is then stopped not after a fixed time, but depending on the achieved core temperature. Core temperature sensor ben, however, have the disadvantage that they must be present on the one hand, on the other hand, they must be inserted correctly and that they are not or can not be readily used in many products, such as frozen food, small food, such as peas, etc.

The present invention is therefore based on the object of specifying a method for operating a cooking appliance in the form of hot-circulating oven, a combi steamer or a combi steamer, with the automatic adjustment of the cooking time depending on the load in the oven, without the use of a core temperature is realized ,

This object is solved by the features of claim 1.

The method according to the invention is characterized in that, starting from a cooking time stored in the storage unit for a specific type of food with a minimum loading of the cooking space from an initial temperature value (T_Start) to a target temperature value (T_Soll) Temperature course is determined in the oven, and if so to what extent results in a time delay until reaching the target temperature value, and that based on the detected time delay, the cooking appliance control calculates a cooking time extension by which the current cooking program step is then extended. In other words, the extension of the cooking time is determined from the temperature profile in the oven. The approach of the method is to initially attach due to the loading of the cooking appliance because of the necessary heating for the cooking process missing energy at the end of the cooking process, ie to extend it so far that is cooked with this energy in addition. This lack of energy for cooking is determined from the temperature profile by the difference between the target temperature or cooking space set temperature (T_Soll) at which takes place after heating the cooking process, and the current oven temperature, which prevails over the surface of the products between the Time of closing the door and reaching the setpoint temperature in the oven at is integrated. Since the temperature difference is proportional to the heat flow into the product, the time integral over this temperature difference is proportional to the introduced energy. For the linear increase of the oven temperature, this integral is proportional to the initial triangular area in the cooking temperature curve.

Food and food or cooking products can be divided into different categories, such as baked goods, meat, fish, vegetables, etc. If the different products differ in their cooking behavior, this can be taken into account in the calculation of the cooking time. This can be done in particular by using correction factors or scaling factors, which leads to a more accurate calculation and thus optimization of the cooking time of the respective cooking product. It is correspondingly advantageous that, according to the present invention, the stored cooking programs are assigned to product categories and the product categories are assigned specific scaling parameters which are included in the calculation of the cooking time extension. This allows a finer adaptation to the particular cooking product, as can be easily understood in the different products: baked meat, fish or vegetables.

The present invention thus also comprises an optimization of the cooking time adjustment depending on the category of the items to be cooked, the items to be cooked and / or the cooking programs, which can lead to different calculations of the respective cooking times. In particular, in addition to the product category (meat, fish vegetables) and the Garart (heating, roasting, roasting, browning, etc.) can be included in the calculations of cooking time extension, because the efficiency of the heat transfer depends, inter alia, on the Garart used. For example, when heated with steam, the heat transfer through the transition of heat of condensation on the food is more efficient than with pure hot air or give different values for the cooking steaming over the cooking grilling. For more precise control of the corresponding cooking process depending on the amount of feed of the cooking chamber, the thermal starting situation in the cooking chamber is taken into account or determined at the start of the cooking process when calculating the cooking time extension. There are differences for the length of the cooking time, whether the cooking space is already heated at the beginning of the cooking process or Not. In a preferred embodiment of the invention, the method is based on a preheated cooking space, wherein it is assumed with minimum feed that the actual temperature in the cooking space does not substantially change after the minimum feed, ie essentially no cooling is detected. If cooling is detected, it is assumed that a larger amount of feed, which requires a corresponding cooking time extension.

A cooking process can consist of several steps or phases. A problem to be solved is repeated at each phase of the cooking program in which the target temperature increases compared to the previous phase. That is, the extension must be done in multi-step cooking programs per step. It should be noted, however, that in contrast to the first cooking step in which a preheated cooking chamber is present, now also the cooking chamber itself including its built-in parts must be heated with. This means that even with a minimum amount of loading, it takes a certain amount of time until the new, higher cooking step temperature is reached. In such a case, however, there is no cooking time extension, which is taken into account by the cooking appliance control.

Advantageously, the temperature profile is monitored in the cooking chamber after introduction of the food over a longer period of time and the temperature rise is averaged. This ensures that minor temperature variations will not lead to incorrect temperature gradients that can cause a wrong extrapolation of the required cooking time extension. These influences can be, for example, the reversing of the circulating air blower in the cooking chamber.

Thus, it is also advantageous that the rising temperature gradient or the slope of the temperature rise only after at least 50%, preferably reached about 80% of the target temperature value or at least 50%, preferably about 80% of the set cooking time has elapsed, is determined and from this the expected cooking time extension is calculated.

The present invention also includes a cooking device in the form of a hot-air circulating oven, a combi steamer or a combi steamer which is suitable and capable of carrying out the method according to the invention. After investigation the cooking time extension time t_b sets the control or regulating device present in the cooking appliance, the cooking time to this value.

Further details, features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. It shows:

Fig. 1 is a perspective view of a cooking appliance, which is suitable for carrying out the method according to the invention;

FIG. 2 shows a further perspective view of the cooking appliance of FIG. 1 with the cooking chamber door removed; FIG.

3 is a graphic representation of an idealized cooking process; and

4 shows an example of an actual cooking process detected by means of sensors.

In the drawings, like elements are designated by the same reference numerals.

1 and 2, a cooking appliance 1 in the form of a combi steamer is shown in perspective view, which is suitable to carry out the inventive method. The cooking appliance 1 has a housing 3, with a front cover wall 5, a cooking chamber 6, which is closed by a cooking chamber door 7 and is accessible by this after the opening. The cooking appliance 1 furthermore has a left side wall 9, a right side wall 1 1 (FIG. 2) and a top wall 13. To open and close the cooking chamber door 7, a door handle 15 is provided.

In the front cover wall 5 is a display and control panel 17, which is designed in the form of a touch screen. By directly touching certain fields, an input signal can be transmitted to the device control. The subdivision of the display and control panel 17 is shown in more detail in FIG. The display and control panel 17 has various partial display and control panels. In this case, a touch screen 61 is provided in a rectangular shape, with which an input can be made by touching, by responding to the device control corresponding additional touch screens are displayed to allow the subsequent inputs and display the associated Gargerätezustand. As a result, the control of the cooking appliance 1 can be performed by the user in a simple manner. Above the touch screen 61 is a row field 62, in the left of a speaker 64 is provided, which is not visible on the customer device, because it is covered with a design film. On the right side there is an on / off button 66 for the cooking device 1, which is preferably also formed touch-sensitive. Below the touch screen 61 is another design surface 68, which may optionally be formed as a further display and control surface.

In Fig. 2, the cooking chamber door is removed for clarity and gives the view in the cooking chamber 6 even better. Fittings such as air baffles and Gargutträgerhalterungen are also hidden. The cooking chamber 6 is bounded by a rear wall 12 at the rear and further has a cooking chamber bottom 25. In the cooking chamber bottom, a drain opening 27 is provided, through which any liquid and also extinguished vapors can be removed. They are led to a liquid reservoir (not shown) below the cooking chamber bottom 25. On the rear wall 12 is a temperature sensor 35 which detects the temperature in the cooking chamber 6.

As can be seen from FIG. 2, the cooking appliance 1 has a fan wheel 29, which is surrounded by a heating device 31. The embodiment of the cooking appliance according to FIGS. 1 and 2 shows a "direct" steaming in which water is fed into the interior of the fan 29 by means of a pipe 33, distributed by the fan 29 and thrown onto the heater 31 where the water evaporates , Of course, cooking appliances for carrying out the method according to the invention are also suitable in which a separate steam generation takes place outside the cooking chamber 6 and steam is introduced into the cooking chamber 6 for steaming.

FIG. 3 graphically illustrates in a diagram an idealized cooking process from an initial temperature value T_Start to a target temperature value T_Soll over the time t. Horizontal is the time axis t and vertically the temperature axis T shown.

The graph of FIG. 3 shows an idealized cooking course of a cooking step during loading. In the cooking steps, the target temperature T_Soll and the cooking time t_1 are predetermined for the loading of a sheet. The extended cooking time t_b with existing loading is determined from the cooking temperature profile.

Idealizing, the heating starts at time 0 at a cooking chamber temperature T_Start and reaches the temperature T_Soll after a time t setpoint. The slope of the temperature rise depends strongly on the degree of loading of the combi steamer. The triangular area A_aufheizen with the vertices (0, t_Soll) (0, T_Start) and (t_Soll, T_Soll) is thus different in size depending on the load. The surface area A- heat up is a measure of the energy which must initially be entered into the cooking chamber so that all the cooking pieces outside are heated up to set temperature T_Soll. The surface area of A_heating is: 0.5 x t setpoint x (T_set - T_start).

The energy input into the food for the single-sheet loading is given by the surface area of the rectangle with the vertices (0, T_Soll), (0, T_Start), (t_1, T_Start) and (t_1, T_Soll). The area of A_Energieeintrag is: t_1 x (T_Soll - T_Start).

The approach of the method is to introduce the increased amount of energy compared to the one-sheet loading following the achievement of the single-sheet target cooking time t_1. Accordingly, the extended cooking time is as follows: t_b = t_1 x (A_Energieeintrag + S x A_aufheizen) / A_Energieeintrag. Here, S is a device-specific scaling factor. This consists of two factors, namely Garart and product category together according to, for example, the following table:

As can be seen from FIG. 3, the area value of the triangle A_aufheizen is connected to the rectangular area A_Energieeintrag as a rectangular area A_Garzeitergänzung, resulting in the value for t_b for the cooking time extension. In the illustrated example, the factor S = 1, 0.

The detection of frozen goods (TK-Ware) in the cooking steaming, which is usually carried out at 100 ° C, thereby, that in this case the cooking space temperature after completion of the preheating and introduction of the food falls below 55 ° C.

With reference to FIG. 4, the detection of the slope of the cooking chamber temperature after introduction of the cooking product will now be described. The values on the time axis (horizontal) are given in seconds and the temperature values (vertical) in ° C. There are three curves: a curve A representing the measured temperature values, a curve B representing the averaged temperature values and a curve C representing the calculated slope of the temperature or the ascending temperature gradient. With the help of the calculated slope, the time can be determined when the desired target temperature or the target temperature value is reached. From this, as explained with reference to FIG. 3, the cooking time extension is then calculated.

After the introduction of the food in the oven, it cools down according to the amount and the temperature of the food. By introducing the heating power by means of the heater, the temperature rises again in the cooking chamber and on.

If the temperature in the cooking chamber is low, further effects can occur which can lead to a further decrease in the temperature.

When considering the above curve, in particular the real measured temperature profile, it is noticeable that the measured temperature before the lowest point partially rises briefly. In addition to unspecified effects, for example, a change in the flow could occur, for example. the direction of rotation reversal of the fan or fan speed change or even a change in the Beschwadung lead to the temperature fluctuations shown.

When determining the slope of the temperature profile, these effects must be taken into account and eliminated. For this, the temperature profile must be monitored over a longer period of time. In order to smooth the temperature profile, in order to eliminate smaller fluctuations in the temperature profile, the calculation is carried out on a moving average of the temperature over a course of at least 30 seconds.

As soon as the temperature rises, a first reference point for the measurement of the slope is detected. In this case, a 30 s average is formed. If a "minimum" is detected, a first reference point is set, and as soon as the slope becomes 0, a second reference point is taken, but if the slope subsequently increases again and then reaches 0 again, the first second reference point is abandoned and the now determined If, on the other hand, the incline then assumes a negative value again, both reference points are discarded and the recording of the reference points begins again. The evaluation of the slope of the temperature takes place as soon as both reference points have been determined and either the temperature has reached 80% of the target temperature or setpoint temperature or 80% of the set cooking time has elapsed. This ensures that the slope can be reliably determined and the correct reference points are determined.

If these are fixed, the pitch line is extended until it intersects both the 0-time axis and the T-desired line, resulting in the full trimmer A_aufheizen whose area is used for cooking time extension determination, as explained above.

If no slope can be determined, e.g. the termination conditions are already met at start, or there is a negative slope, the setpoint should not be used. For example, if the setpoint temperature is present at the start of the calculation. This can happen if the cooking chamber has been preheated to a higher temperature than the setpoint temperature and little or no food or food with low heat capacity is charged. Then the normal cooking time remains.

Other influencing factors should be taken into account. In particular at low temperatures, steaming by means of direct water injection can have a negative effect on the measurement result, as this generally additionally cools the cooking chamber.

The present invention follows a basic principle: it works on the pattern of a cooking program for a very small batch of how to make a sheet. Such cooking programs can be product-dependent and Garartabhängig also optimized by the user or other cooking programs are stored in the storage of the cooking appliance. The cooking chamber temperature after loading is substantially not reduced at this low feed. Advantageously, corresponding values of a minimum charge in the electronic cooking appliance control, if appropriate after optimization, can thus be stored as initial values for each cooking type and for each cooking product. If the device controller determines that the rising temperature gradient is different from the stored one, it determines that a larger charge has taken place and calculates accordingly the cooking time extension. Cooking appliances, such as professional combi steamer, can, at the start of the cooking time calculation, take account of settings such as the category, the food or the cooking program in addition to the cooking style. Depending on the respective category, the calculation of the cooking time extension for meat in this example results in a different value compared to the value for bakery products and thus becomes a different one Cooking time extension performed.

According to the invention, there is also the advantage that different calculation modes or scaling factors for, for example, different types of meat (roast pork, roast beef, veal shank, etc.) and even for different types of preparation (cooking programs) can be stored in the control of the cooking appliance.

The user of the cooking appliance preferably develops a cooking program which achieves an optimum cooking result for a minimum amount of cooking product. The user can choose the cooking mode, duration, humidity and fan speed (flow generating device). The cooking program created in this way is stored by the user in a product category, whereby this advantageously gives a name.

Ideally, the cooking appliance is preheated after the start of the corresponding cooking program and before loading. This can be done automatically or triggered manually. After the device control has indicated by indications on the display and operating device 17 and / or by signal output, for example acoustically, to the user that the target temperature or pre-heating temperature has been reached, the user feeds the cooking chamber 6 with an unknown quantity for device control to food intended for the selected cooking program. The device control stores in its memory the course of the oven temperature. Due to the introduction of the cold food to frozen food, the atmosphere in the cooking chamber 6 initially cools off, as can be seen from FIG. 4 according to curves A and B. The degree of cooling depends on the amount of food to be cooked, the duration of the charging process, during which the heating function is interrupted, and the temperature of the food. After some time, the temperature rises again (first turning point). The time required to reach the set temperature is stored, depending on the load of the food. With a very small amount, the setpoint temperature is reached again quickly or immediately after the start of the cooking program. At higher loadings, the additional time required and thus the cooking time extension can be up to 50% of the total cooking time, which represents a considerable value. If the cooking time extension is omitted or if it is not sufficient, which the user can not or hardly can estimate, the desired cooking result does not set.

For an accurate detection of the oven temperature during the heating phase, the position of the temperature sensor 35 within the cooking chamber 6 is of crucial importance. It makes a significant difference whether the temperature sensor is placed near the heater or in the vicinity of the food. According to the invention, the temperature sensor 35 is located in the vicinity of the food to be cooked or, alternatively, in the intake region of the fan wheel 29 of the flow-generating device. For example, with the present invention, it is possible to calculate the cooking time for a full load of fresh beef to be cooked "medium" based on empirically determined data and the stored calculation formulas or algorithms Calculation of incoming empirical values significantly different from the cooking time of a full load with baked goods, although the respective cooking program may require a comparable or similar cooking climate or the cooking appliance control or the operator sets a comparable cooking climate. With the present invention, a significantly improved cooking result when operating a combi steamer over the prior art is thus achieved without the use of a core temperature sensor.

LIST OF REFERENCES

1 - cooking appliance

3 - housing

5 - front cover wall

6 - cooking space

7 - Garraumtür

9 - left side wall

1 1 - right side wall

12 - rear wall

13 - ceiling wall

15 - door handle

17 - Display and control panel (touch screen)

19 - hose shower

21 - Supply air pipe

22 - cap

23 - exhaust pipe

25 - Garraumboden

27 - drain opening

29 - Fan wheel

31 - heating device

33 - Damping pipe

35 - Temperature sensor

61 - Display and control panel (touch screen)

62 - line field

64 - speakers

66 - On / Off button

68 - Design surface A - measured temperature B - averaged temperature C- calculated slope

Claims

Patent claims

Method for operating a cooking appliance (1) in the form of a hot-air oven, a combi steamer or a combination steamer, which has a cooking space (6) that can be closed with a cooking space door (7), a heating device (31), at least one steaming device (33 ), at least one flow generating device (29), such as a fan, at least one temperature sensor (35), which detects the temperature in the cooking chamber (6), and an electronic device control with a memory unit in which cooking programs are stored, which include cooking processes for specific cooking products , characterized in that, starting from a cooking time stored in the storage unit for a specific type of food to be cooked with a minimum loading quantity of the cooking chamber from an initial temperature value to a target temperature value, it is determined based on the recorded temperature profile in the cooking chamber (6) whether and if so by what extent there is a time delay until the target temperature value is reached, and that based on the detected time delay, the electronic cooking appliance control calculates a cooking time extension by which the current cooking program step is then extended.

Method according to claim 1, characterized in that the stored cooking programs are assigned to product categories, and that the product categories are assigned specific scaling parameters which are included in the calculation of the cooking time extension.

3. The method according to claim 1 or 2, characterized in that cooking-specific factors that are assigned to the cooking programs are included in the calculation of the cooking time extension.

Method according to one of claims 1 to 3, characterized in that when the cooking process starts, the initial thermal situation in the cooking space is taken into account or determined when calculating the cooking time extension.

Method according to one of claims 1 to 4, characterized in that in a subsequent cooking step, the thermal inertia of the cooking space and the non-cooked material within the cooking space necessary for the cooking operation is taken into account when calculating the cooking time extension of the subsequent step.

Method according to one of claims 1 to 5, characterized in that the temperature profile in the cooking space is monitored over a longer period of time after the food has been introduced and the temperature increase is often averaged.

Method according to one of claims 1 to 6, characterized in that the slope of the temperature increase is determined after at least 50%, preferably approximately 80% of the target temperature value has been reached or at least 50%, preferably approximately 80% of the set cooking time has elapsed and from this the expected cooking time extension is calculated.

Cooking appliance (1) in the form of a hot air oven, a combi steamer or a combination steamer, which has a cooking space (6), which can be closed with a cooking space door (7), a heating device (31), at least one steaming device (33), at least a flow generating device (29), such as a fan, at least one temperature sensor (35), which detects the temperature in the cooking chamber (6), and an electronic device control with a memory unit in which cooking programs are stored, which include cooking processes for specific cooking products, characterized in that it is suitable and capable of carrying out the method according to the invention according to one of claims 1 to 7, wherein after determining the cooking time extension time, the electronic device control sets the end of cooking time to this value.

9. Cooking appliance according to claim 8, characterized in that the temperature sensor (35) is arranged away from the heating device (31) and in the vicinity of the food to be cooked or in the suction area of the flow generating device (29).