DD215189A1 - METHOD AND DEVICE FOR REGULATING THE BAKING PROCESS IN HOUSEHOLD BAKING MACHINES - Google Patents

Abstract

The invention relates to a device for controlling the baking process in Haushaltsbackgeraeten. The aim is to maintain the optimum baking time and baking temperature in accordance with the baking product while at the same time using the heating and remaining heat. The boundary layer temperature between the baking piece and the baking dish is dependent on the specific heat capacity and the mass of the baking item, provided the supplied heat quantity is known. If this measured temperature is fed to a programmed information processing unit, then the optimum baking time and baking temperature can be regulated, taking into account the residual heat. Minor disturbances (for example opening the baking chamber door) are compensated independently. By suitable mechanical means, the baking chamber temperature can be reduced so far after the end of the baking process that a removal of the baking piece from the baking chamber is not absolutely necessary. Since all subjective influences are eliminated, optimal quality of food is achieved with the least amount of energy. The invention can be applied to all Haushaltsbackgeraete.

Description

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Method and device for controlling the baking process in home baking appliances Field of application of the invention

The invention relates to a method and a device for automatic regulation of the baking regime for different doughs and masses, hereinafter referred to as baking, in Haushaitsbackgeräten by detecting the dependent on the particular recipe thermal conductivity and temperature of Teigbackstückes and the resulting optimization of the baking time and heating power.

Characteristic of the known technical solutions

In domestic bakery, the quantity of heat Q supplied is currently measured by the empirically selected baking time and oven temperature.

An optimal amount of heat Q is dependent on the mass m of the baking piece, the specific heat capacity c of the baking piece and the difference between the initial and final temperature ΔΤ _{ΑΕ of} the baking piece. In this case, the specific heat capacity c depends on the recipe of the baking piece. An optimal amount of heat Q is therefore different even for the detection of the parameters temperature T and baking mass m for each recipe. It must be determined as a function of the mentioned parameters m, c and ΔΤ _Α £. Since the determination of the specific heat capacity c in the household is objectively not possible, the housewife uses subjective methods, which are not an optimal baking regime. allow the constant control of the baking process and in which the heating phase and the existing residual heat of the baking device are used inadequate. ·. ·.

To solve the problem, methods for home baking appliances are known in which the parameters baking time and oven temperature run according to fixed programs. These programs apply to certain selected pastries. The disadvantage lies primarily in the fact that for the individual pastry a standard recipe is adopted, which in practice only exceptionally fully applies and which is affected even in the proposed shares of the basic components by their physical and chemical deviations. A sufficiently differentiated control of the baking regime therefore requires a variety of fixed programs, in practice to over 100. Since the household bakery is individually shaped, on the one hand a large part of these programs are not used, but used too little.different. Each reduction and globalization of the number of programs, however, in turn leads to inaccurate recording of the recipe-specific parameters of the baking process in a specific case.

In recognition of these shortcomings, home baking appliances with programmable bakery were developed. Here, the baking chamber temperature and baking time is selected on the basis of empirical values or according to the suggestions from the operating instructions. In addition, it is possible to specify the surface temperature or the temperature at an arbitrarily and randomly placed in the crumb location of the temperature sensor. Here, too, individual formulation differences as well as physical and chemical deviations of the individual components can only be considered insufficiently, since the operating instructions are also based on average values. If a powerful heat source is used (eg microwaves), it is possible to divide the baking time into intervals of heating phases, with the aim of avoiding overheating of the baking piece. Such programming already requires certain previous knowledge and skills that can not be assumed without appropriate practice and experience (DE-OS 2,938,980). In order to eliminate the programming effort, a method is known by which the reflected radiation from the material surface is detected and used to control the heat supply. In this case, a light beam is brought to the surface of the baking piece by a constant radiation source, reflected by this in dependence on the degree of browning and detected by a measuring device. The thus detected reflection value is used to control the further heat supply in the form of heating power or baking time. The disadvantage is that the measured surface tanning under the influence of various baking temperatures is not an expression of the heat kinetics inside the bag piece, so that even with strong browning the baking process need not be completed, especially with different geometric shape of the bakery pieces. In addition, the measured reflectance value can be falsified by the color of the individual bakery pieces due to lighter or darker components. Thus, the application area is narrowed from the outset or additionally requires the consideration of the geometric shape and color of the baking piece. In Ausführungsbeispiei beyond a high metrological and maintenance costs is recognizable (DE-OS 2,021,247). On a similar principle, a known device is based, is detected by sensors, the change in the electrical conductivity of the pastry surface as a function of their degree of browning. In addition to the deficient statement of the browning for baking the baking piece, the electrical conductivity is also affected by certain ingredients, such as salts, sugars and fats. Therefore, this method is only suitable when toasting special, intended baking (DE-OS 2,648,865).

From the USA, finally, a device is known which analyzes the baking chamber atmosphere and draws conclusions on the loss of baking and thus on the degree of frying from the absolute moisture content. The analysis value obtained is used to control baking time and baking temperature. But this could not enforce because of the high metrological cost, the required exactly defined conditions and also because of the very different moisture content of the individual baked goods as a function of raw material fractions used (US Patent No. 3,839,616).

Object of the invention

The aim of the invention is to automatically lead in the household bakery of bakery pieces of any recipe and geometric shape, the baking regime so that with minimal energy consumption baked in optimum quality pastry, while a high ease of use without care and maintenance-intensive measuring devices is achieved. This is to be used in contrast to previous devices and devices, the heating and the residual heat of the baking unit.

Explanation of the essence of the invention

The invention is based on the object to supply the baking piece required for optimum baking amount of heat. Here, the amount of heat applied during the baking process by changing the baking chamber temperature T _B is to differentiate so that an optimum feeding of the amount of heat T _opt is carried out during the heating phase to achieve optimum baking room temperature in the baking phase, these T _opt is kept constant at a

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certain Äusbackzustand the heat supply is terminated and in the final phase, the residual heat in the oven is used for the final baking.

According to the invention, the object is achieved in that in the baking pan or in the baking sheet (hereinafter referred to as baking mold), a temperature sensor is incorporated so that it continuously measures the temperature in the boundary layer between baking mold and baking piece and supplies the detected value to a computer. This computer is already programmed by the manufacturer so that all typical boundary layer temperature profiles are stored. From the comparison of the measured temperature profile with the stored values, the optimum oven temperature and baking time can be determined. ,

In the heating phase, heating of the baking chamber and baking mold takes place with maximum heat input.

As a result, the boundary layer temperature T _G measured by the temperature sensor changes depending on the specific heat capacity c of the baking piece. Within a defined time difference Δt ₁ after the onset of heating power from the thus measured temperature difference _AT · _G , the specific heat capacity c _{s is} closed by the computer and since this is recipe-dependent, the recipe can be determined therewith. This information will

saved. , , ,

In the course of the heating phase, the baking piece is increasingly heated. Since, given a defined amount of heat, this temperature change depends on the mass of the component, the temperature sensor measures the temperature difference AT _G2 as an expression of the mass of the component in time At ₂ . By the computer is closed from this temperature difference on the mass of the baking piece and this also stored. :

From the information thus obtained AT _G1 and AT _G2 is determined by the computer, the optimal baking temperature and realized by controlling the heating. At the same time, the computer of the said information determined by specific heat and mass of the back piece, the optimal baking time At _ges.

When the optimum baking temperature is reached, the baking phase begins, in which the baking temperature T _{opt is} kept constant until the calculated end time. The heat supply is then terminated, taking into account the residual heat for baking.

Within the baking phase, the temperature sensor assumes the function of process control and continuously measures the boundary layer temperature, which must be kept within certain tolerances, on the one hand to allow the baking process and on the other hand to prevent deterioration of the pastry quality. If the tolerance values are exceeded or fallen below as a result of disturbances in the baking process, the heat supply or the baking time is corrected by the computer.

After completion of the heat supply begins the final phase in which using the residual heat, a final baking takes place. The temperature sensor continuously measures the temperature drop in this phase, compensates for disturbances and gives an optical or acoustic signal when reaching the Ausbackzustandes, which allows removal of the finished baking piece. Optionally, such ventilation and lowering the temperature in the oven can be achieved by additional mechanical means that removal of the finished baking piece from the oven at a later date

can be done. :

Ausführungsbeispiei

In the following, the invention will be described by the description of an example of practical implementation with reference.

explained to the accompanying drawings.

Fig.1 Device for controlling the baking process in home baking appliances, schematic diagram Fig.2 Device for controlling the baking process in home baking appliances, block diagram Fig.3 Device for controlling the baking process in home baking appliances, temperature history in the oven and on the baking tray

Temperature sensor \

In a baking chamber 1, a baking mold 3 is introduced. In the baking mold of the temperature sensor 4 is integrated, which is connected via a connection 6 with a computer 7 (information processing unit). On the basis of the information obtained in the time At ₁ , the power of the heating elements 2 are regulated via a regulator 8. By the value of AT _G2 obtained in the time unit t ₂ , an optimal baking chamber temperature T _{opt is} predetermined. In the time At ₃ , the heat supply to .Backstück is controlled and compensated for deviations from the predetermined baking regime via the controller 8 and the heating elements 2. Via a temperature sensor 9, the baking temperature in conjunction with the controller 8 and the heating elements 2 at a constant. Kept level. On the basis of the information b at ₂ , the computer determines the time t ₃ . After reaching t ₃ , the heating elements 2 are switched off. By further measuring the baking chamber temperature by the sensor 9, the temperature reduction is controlled and maintained at deviations through the controller 8 and the heating elements 2 in the predetermined limits (^ a). By the temperature sensor 4, the mechanical device for the cooling of the baking chamber 10 is confirmed after reaching t _E via the computer 7 and / or triggered acoustic and / or visual displays. '. ,

Claims (4)

-3- 249908 2 Invention claim: 1. A method for controlling the baking process in home baking appliances, wherein the baking process is divided into several heating phases, characterized in that continuously during the baking process, the temperature in the boundary layer between baking mold (3) and baking piece (5) and in the oven chamber (1) measured both measured results fed to a known information processing unit (7), the information processing unit (T) in the heating phase from the measured temperature difference or from the rise of the curve (Figure 3) determines an optimal oven temperature and baking time, taking into account specific heat capacity and mass and so that the heating power controls; in the baking phase, the baking chamber temperature determined by the information processing unit (7) is kept constant and, after completion of the baking time calculated by the information processing unit as optimally calculated taking into account the residual heat, is switched off; in the final phase, the residual heat is used for final baking and is displayed at a predetermined cooling temperature of the completion of the baking process by signal. 2. The method according to item 1, characterized in that for error compensation, the boundary layer temperature between the baking piece (5) and baking mold (3) continuously measured during the baking phase and final phase and when exceeding or falling below tolerance values, the specific heat and / or the baking time is corrected. 3. Apparatus for carrying out the method according to item 1 and 2, consisting of heating or baking chamber with heating elements, baking mold, temperature control device, mechanical device for cooling the oven and regulator for controlling the heating power, characterized in that in the baking chamber (1 ) located in the baking chamber (1) a further temperature sensor (9) is arranged, both directly to a known information processing unit (7) are connected and the information processing unit (7) with the controller (8) and the mechanical means for cooling the baking chamber (10) are in communication. / 4. The device according to item 3, characterized in that in the baking mold (3) heating elements are arranged.