AN OVEN

[0001] The present invention relates to an oven the cooking quality of which is provided not to be adversely affected when the door thereof is opened and which is provided to operate in a safe manner.

[0002] In ovens, some users need to control if the food being cooked is cooked or not by opening the oven door during the cooking process. When the door is opened, the internal temperature of the oven decreases and this situation affects the cooking quality adversely. Moreover, when the door is opened, hot air or vapor diffusion takes place and this situation causes the user to be harmed.

[0003] In the state of the art Japanese Patent Application No. JP59231331 , a cooking device comprising a control unit which provides the cooking process not to be affected adversely from the door being opened is described.

[0004] The aim of the present invention is the realization of an oven the cooking quality of which is provided not to be adversely affected when the door thereof is opened and which is provided to operate in a safe manner.

[0005] The oven realized in order to attain the aim of the present invention,

explicated in the first claim and the respective claims thereof, comprises a sensor detecting instantaneous fan speed and a control unit calculating the amount of change in fan speed according to the data transmitted by the sensor. The control unit compares the amount of change in fan speed with the limit amount of change in fan speed predetermined by the producer and saved in the memory thereof and decides that the door is opened when the amount of change in fan speed is equal to or greater than the limit amount of change in fan speed. The control unit provides changes to be made in the cooking steps upon detecting that the door is opened. Thus, the cooking quality is prevented from being affected adversely as a result of the door being opened and also user safety is guaranteed.

[0006] In an embodiment of the present invention, the control unit stops the vapor spraying upon detecting that the door is opened. Thus, the user is prevented from being harmed.

[0007] In another embodiment of the present invention, the control unit provides the heaters to operate such as to compensate the temperature decrease in the cooking chamber occurring as a result of the door being opened when the door is closed again upon detecting that the door is opened.

Thus, the cooking quality is prevented from being affected adversely as a result of the door being opened.

[0008] By means of the present invention, the opening of the door is detected by monitoring the amount of change in fan speed, and unwanted situations such as the cooking quality being deteriorated, the user being in danger as a result of the door being opened are prevented.

[0009] The model embodiments relating to an oven realized in order to attain the aim of the present invention are illustrated in the attached figures, where:

[0010] Figure 1 - is the sideways schematic view of an oven.

[001 1] Figure 2 - is the graphic showing the change in fan speed by time in an oven.

[0012] The elements illustrated in the figures are numbered as follows:

1. Oven

2. Body

3. Cooking chamber

4. Door

5. Heater

6. Fan

7. Motor

8. Shaft

9. Sensor

10. Control unit

[0013] The oven (1 ) comprises a body (2), a cooking chamber (3) located in the body (2), wherein foods to be cooked are placed, a door (4) providing access to the cooking chamber (3), at least one heater (5) providing the air in the cooking chamber (3) to be heated, a fan (6) moving the air heated by the heater (5), a motor (7) providing the fan (6) to be driven, at least one shaft (8) providing the drive provided by the motor (7) to be transferred to the fan (6) and a sensor (9) placed onto the motor (7) such as to face the shaft (8), detecting the instantaneous fan speed (N) (Figure

1 ).

[0014] The oven (1 ) of the present invention, furthermore comprises a control unit (10) which determines the amount of change in fan speed (DN) by calculating the difference between two consecutive instantaneous fan speed (N) measurements detected by the sensor (9) in the time period (ti) predetermined by the producer, which detects that the door (4) is opened when the amount of change in fan speed (DN) is at least as much as the limit amount of change in fan speed (DNIimit) predetermined by the producer and which accordingly provides changes to be made in cooking steps.

[0015] The instantaneous fan speed (N) is directly affected by the cooking

chamber (3) temperature. The instantaneous fan speed (N) increases as the cooking chamber (3) temperature increases during the cooking process. Similarly, the instantaneous fan speed (N) decreases as the cooking chamber (3) temperature decreases during the cooking process. When the door (4) is opened, a sudden decrease in the cooking chamber (3) temperature occurs. Therefore, in this case the fan speed (N) also decreases (Figure 2).

[0016] The instantaneous fan speed (N) is measured by the sensor (9) and

transmitted to the control unit (10). The control unit (10) calculates the amount of change in fan speed (DN) by comparing the consecutive instantaneous fan speeds (N) with each other. For example, when the instantaneous fan speed (N 1) at t1 and the instantaneous fan speed (N2) at t2 are transmitted to the control unit (10), the control unit (10) calculates the amount of change in fan speed (DN) as N2-N1. The amount of change occurring in fan speed (DN) when the door (4) is opened predetermined as the result of experimental studies undertaken is saved as the limit amount of change in fan speed (DNIimit) to the control unit (10) memory by the producer. The control unit (10) detects that the door (4) is opened when the amount of change in fan speed (DN) calculated by the control unit (10) is equal to or greater than the limit amount of change in fan speed (DNIimit) (Figure 2). In this situation, the control unit (10) takes precautions to provide the cooking quality not to be deteriorated and to provide user safety. Thus, adverse effects that an external factor such as the opening of the door (4) creates on the cooking quality are eliminated. Moreover, safe conditions of use are provided by eliminating effects which can occur by the door (4) being opened and which can risk user safety.

[0017] In an embodiment of the present invention, the control unit (10) stops the vapor spraying upon as it detects that the door (4) is opened. Thus, the user safety is provided by stopping vapor diffusion from the cooking chamber (3) upon the opening of the door (4).

[0018] In an embodiment of the present invention, the control unit (10) provides the heaters (5) to operate such as to compensate the temperature loss occurring in the cooking chamber (3), when the door (4) is closed again after detecting that the door (4) is opened. Thus, adverse effect on the cooking quality that the opening of the door (4) causes is decreased.

[0019] In an embodiment of the present inventions, the sensor (9) detecting the instantaneous fan speed (N) is "Hall effect" type. Thus, the instantaneous fan speed (N) is detected more precisely.

[0020] By means of the present invention, the door (4) is detected as being open by monitoring the amount of change in fan speed (DN) calculated by the control unit (10) according to the instantaneous fan speed (N) and the cooking quality and the user safety are provided not to be adversely affected by the door (4) being opened.

[0021] It is to be understood that the present invention is not limited to the

embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.