EP3264900A1

EP3264900A1 - A cooking device wherein the heater is controlled

Info

Publication number: EP3264900A1
Application number: EP16707740.3A
Authority: EP
Inventors: Asli Saime Kayihan; Aziz CELIK
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2015-03-04
Filing date: 2016-03-02
Publication date: 2018-01-10
Also published as: WO2016139246A1

Abstract

The present invention relates to a cooking device (1 ) comprising a cooking chamber (2); a heater (3) that heats the cooking chamber (2); a user interface (4) whereby the user sets the cooking temperature (Tset), and a control unit (5) that enables the realization of a preheating phase at the beginning of the cooking process by continuously heating the heater (3) until the cooking chamber (2) reaches the cooking temperature (Tset) set by the user and that periodically turns on/off the heater (3) for an on time (ton) and for an off time (toff) during the cooking process.

Description

A COOKING DEVICE WHEREIN THE HEATER IS CONTROLLED

The present invention relates to a cooking device wherein the heater is controlled during the cooking process.
In cooking devices, for example in household ovens, different food types are cooked at a temperature set by the user. In order to cook certain foods, for example pastries, a preheating phase is required. In a cooking process comprising a preheating phase, the user sets the temperature inside the oven to a desired degree and places the foodstuff into the oven when the temperature inside the oven reaches this degree. After the preheating phase, the heater is controlled by different methods in order to keep the inner temperature of the oven at the cooking temperature set by the user. In the state of the art embodiments, the heater is controlled according to the difference between the instantaneous inner temperature of the oven and the cooking temperature. In this case the heater is turned on/off many times, thus the electronic circuit components may be damaged. Moreover, with the heater being controlled by complex algorithms, an excessive load is imposed on the control card and a need for using high-capacity memory cards arises.
In the state of the art International Patent Application No. WO2005008136, a cooking device is explained wherein the heater is controlled according to the difference between the instantaneous inner temperature of the oven and the cooking temperature.
The aim of the present invention is the realization of a cooking device wherein the heater is operated in an optimum manner and the temperature of the cooking chamber is kept at the cooking temperature.
The cooking device realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a user interface whereby the user sets the cooking temperature and a control unit that enables the cooking chamber to be heated to the cooking temperature by operating the heater continuously during the preheating period and that turns on/off the heater periodically, and the control unit enables the cooking chamber to be kept at the cooking temperature by successively turning on/off the heater during the cooking process after the preheating process for the on and off times determined according to a ratio, for each cooking time, of an on time, which increases in linearly proportional to the cooking temperature prerecorded in its memory, to an off time. In the cooking device of the present invention, only the on time or the off time or both on and on times of the heater is/are determined according the ratio of on time to the off time which is in direct proportion to the cooking temperature set by the user via the user interface. For example, the heater is kept on at high cooking temperatures and thus by preventing heat losses the cooking chamber is enabled to be kept at the cooking temperature.
In an embodiment of the present invention, the control unit keeps the heater off for an off time constant at each cooking temperature and operates the same for an on time that increases in linearly proportional to the cooking temperature. In this embodiment, the heater is periodically turned on/off for the on times determined by the user in direct proportion to the cooking temperature and for an off time constant for each cooking temperature, thus the cooking chamber is kept at the cooking temperature. For example, the heater is respectively turned on/off for the 20 second on time and 10 second off time for the cooking temperature of 250 degree centigrade, thus the temperature of the cooking chamber is kept at around 250 degrees. By means of this embodiment, excessive load is not posed on the control unit since the on time varying for the control of the heater is depended only on the cooking temperature. Thus, the user satisfaction is significantly increased by enabling the cooking device to operate without any problem for a long time.
In another embodiment of the present invention, the control unit operates the heater for an on time constant at each cooking time and keeps the same off for an off time that decreases in linearly proportional to the cooking temperature. In this embodiment, as an alternative to the above-disclosed embodiment, the variable in the control of the heater is the off time. In this embodiment, differently from the above-disclosed embodiment, the heater is kept off for a shorter off time at high temperatures and thus the temperature of the cooking chamber is prevented from decreasing, away from the cooking temperature.
In another embodiment of the present invention, the cooking device comprises a fan that enables the heat provided by the heater to be homogeneously distributed in the cooking chamber and the control unit turns on/off the fan together with the heater. In other works, when the heater is turned on the control unit turns on the fan as well, and turns off the fan as well when the heater is turned off. By means of this embodiment, while the noise level of the cooking device is decreased, the fan is not continuously operated, thus providing energy saving.
In the cooking device of the present invention, the cooking chamber is kept at the cooking temperature by turning on/off the heater for the on or the off times determined according to a ratio of an on time, which changes in linearly proportional to the cooking temperature to the off time. By means of the present invention, the control of the heater is simplified and by optimizing the periodical activation/deactivation of the heater, the load imposed on the control card and the electronic components is decreased.
The cooking device realized in order to attain the aim of the present invention is illustrated in the attached figures, where:
Figure 1 – is the front view of a cooking device.
Figure 2 – is the graphic showing the change, with respect to time (t), in the temperature (T) of the cooking chamber during the cooking process and showing the operation of the heater. In the graphic, the durations wherein the heater is on are shown with “1” and the durations wherein the lamp is off are shown with “0”.
Figure 3 - is the graphic showing the change, with respect to the cooking temperature (Tset), in the on (ton) and off (toff) times of the heater during the cooking process in an embodiment of the present invention.
Figure 4 - is the graphic showing the change, with respect to the cooking temperature (Tset), in the on (ton) and off (toff) times of the heater during the cooking process in another embodiment of the present invention.
The elements illustrated in the figures are numbered as follows:

Cooking device
Cooking chamber
Heater
User interface
Control unit
Fan

The following symbols are used for explicating the cooking device (1) of the present invention:
Tset : Cooking temperature
ton : On time of the heater
toff : Off time of the heater
The cooking device (1), for example the oven, comprises a cooking chamber (2); a heater (3) that heats the cooking chamber (2); a user interface (4) whereby the user sets the cooking temperature (Tset), and a control unit (5) that enables the realization of a preheating phase at the beginning of the cooking process by continuously heating the heater (3) until the cooking chamber (2) reaches the cooking temperature (Tset) set by the user and that periodically turns on/off the heater (3) for an on time (ton) and for an off time (toff) during the cooking process (Figure 1).
At the beginning of the cooking process, the user sets the cooking temperature (Tset) using the user interface (4) by means of the buttons/knobs and starts the cooking process. By continuously operating the heater (3), the control unit (5) enables the temperature of the cooking chamber (2) to reach the cooking temperature (Tset). The temperature of the cooking chamber (2) can be measured by means of the state of the art thermometers. As the preheating process is completed, the control unit (5) periodically turns on/off the heater (3)for the on time (ton) and the off time (toff).
The cooking device (1) of the present invention comprises the control unit (5) that enables the temperature of the cooking chamber (2) at around the cooking temperature (Tset) after the preheating phase by turning on/off the heater (3) during the cooking process, according to the ratio, predetermined by the producer, of the on time (ton), that is in linearly proportional to the cooking temperature (Tset), to the off time (toff).
By periodically turning on/off the heater (3), the control unit (5) enables the temperature of the cooking chamber (2) to be kept at around the cooking temperature (Tset) by benefiting from the heat emanating from the walls of the cooking chamber (2). The ratio of the on time (ton) to the off time (toff) of the heater (3) is determined according to the data obtained as a result of the experiments conducted by the manufacturer so as to be in direct proportion to the cooking temperature (Tset). The control unit (5) calculates the on time (ton) and the off time (toff), that will be used in periodically turning on/off the heater (3) at a cooking temperature (Tset) set by the user, by using the cooking temperature (Tset) recorded in its memory and the function of the ratio (ton/toff) of the on time (ton) to the off time (toff), thus the control unit (3) calculates different on time (ton) and/or off time (toff) for each cooking temperature (Tset). Since there will be a more rapid heat transfer to the environment when the cooking temperature (Tset) is set to a high temperature by the user, at higher cooking temperatures (Tset) the heater (3) is operated by the control unit (5) so that the ratio of the on time (ton) to the off time (toff) is a high value, for example by being kept on for longer on times (ton) and kept off for shorter off times (toff). Thus, the cooking chamber (2) is kept at the cooking temperature (Tset). Similarly, at low cooking temperatures (Tset) the heater (3) is operated by the control unit (5) so that the ratio of the on time (ton) to the off time (toff) is a low value, for example by being kept on for shorter on times (ton) and kept off for longer off times (toff). Thus, while energy saving is provided, by determining the control of the heater (3) by only a single parameter such as the cooking temperature (3), no excessive load is imposed on the control card of the cooking device (1) and moreover, the heater (3) is turned on/off at intervals so as not to damage the electronic components (Figure 3).
In an embodiment of the present invention, the control unit (5) enables the heater (3) to be operated by being turned on/off for an off time (toff) constant at different cooking temperatures (Tset) and for an on time (ton) that increases in linearly proportional to the cooking temperature (Tset). In this embodiment, the heater (3) is kept at the same off time (toff) for each cooking temperature (Tset) and thus the control of the heater (3) is simplified. The cooking chamber (2) is kept at the cooking temperature (Tset) by operating the heater (3) for the on times (ton) that increases in direct proportion to the cooking temperature (Tset) (Figure 3).
In another embodiment of the present invention, the control unit (5) enables the heater (3) to be operated by being turned on/off for an on time (ton) constant at different cooking temperatures (Tset) and for an off time (toff) that decreases in linearly proportional to the cooking temperature (Tset). In this embodiment as an alternative to the above-disclosed embodiment, the heater (3) is operated for an on time (ton) constant at each cooking temperature (Tset) and kept off for an off time (toff) that decreases in direct proportion to the cooking temperature (Tset). Since the cooking chamber (2) more rapidly cools down at high cooking temperatures (Tset), at these temperatures the heater (3) is kept off for shorter times (Figure 4).
In another embodiment of the present invention, the control unit (5) increases/decreases the on time (ton) and the off time (toff) of the heater (3) depending on the heaters (3) with different powers. In this embodiment, the on time (ton) and the off time (toff) of the heater (3) are controlled depending on the power of the heater (3). In other words, the on (ton) and off (toff) times of the heater (3) depending on the cooking temperature (Tset) are adjusted according to the power of the heater (3). For example, the on time (ton) of the heater (3) depending on the cooking temperature (Tset) is two functions parallel to teach other for two different heaters (3) at low power and high power.
In another embodiment of the present invention, the cooking device (1) comprises a fan (6) that enables the heat in the cooking chamber (2) to be homogeneously distributed and the control unit (5) turns on the fan (6) for the on time (ton) of the heater (3) and turns off the same for the off time (toff) of the heater (3). By operating the fan (6) only when the heater (3) is turned on, the heat provided by the heater (3) is enabled to be distributed homogeneously in the cooking chamber (2) and energy saving is provided by operating the fan (6) intermittently.
In the cooking device (1) of the present invention, by controlling the heater (3) depending on a single parameter such as the cooking temperature (Tset), the user satisfaction is improved by operating the cooking device (1) without problems for long periods. In addition, by periodically turning on/off the heater (3) in an optimum manner for the on (ton) and off (toff) times depending on the ratio of the on time (ton), which is determined to be in direct proportion to the cooking temperature (Tset), to the off time (toff), the temperature of the cooking chamber (2) is kept at the cooking temperature (Tset) and the energy consumption of the heater (3) is improved.

Claims

A cooking device (1) comprising a cooking chamber (2); a heater (3) that heats the cooking chamber (2); a user interface (4) whereby the user sets the cooking temperature (Tset), and a control unit (5) that enables the realization of a preheating phase at the beginning of the cooking process by continuously operating the heater (3) until the cooking chamber (2) reaches the cooking temperature (Tset) set by the user and that periodically turns on/off the heater (3) for an on time (ton) and for an off time (toff) during the cooking process, characterized by the control unit (5) that enables the temperature of the cooking chamber (2) at around the cooking temperature (Tset) after the preheating phase by turning on/off the heater (3) during the cooking process, according to the ratio, predetermined by the producer, of the on time (ton), that is in direct proportion to the cooking temperature (Tset), to the off time (toff).
A cooking device (1) as in Claim 1, characterized by the control unit (5) that enables the heater (3) to be operated by being turned on/off for an off time (toff) constant at different cooking temperatures (Tset) and for an on time (ton) that increases in linearly proportional to the cooking temperature (Tset).
A cooking device (1) as in Claim 1, characterized by the control unit (5) that enables the heater (3) to be operated by being turned on/off for an on time (ton) constant at different cooking temperatures (Tset) and for an off time (toff) that decreases in linearly proportional to the cooking temperature (Tset).
A cooking device (1) as in any one of the above claims, characterized by a fan (6) that enables the heat in the cooking chamber (2) to be homogeneously distributed and the control unit (5) turns on the fan (6) for the on time (ton) of the heater (3) and turns off the same for the off time (toff) of the heater (3).