EP2921780A1

EP2921780A1 - Cooking appliance having thermal decomposition function

Info

Publication number: EP2921780A1
Application number: EP13855099.1A
Authority: EP
Inventors: Younghee Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-15
Filing date: 2013-10-01
Publication date: 2015-09-23
Also published as: CN103930006B; BR112015010869A2; EP2921780A4; AU2013345700A1; JP2016502637A; RU2015122094A; WO2014077505A1; KR101306428B1; US20150090247A1; CN103930006A; CA2889658A1

Abstract

The cooking device with pyrolysis function includes a cooking cavity, a heating means located within the cooking cavity for emitting heat, a combustion tube having a hollow portion formed to surround the heating means, the combustion tube being heated by the heating means and radiates its heat to the center of the cooking cavity, a combustion space formed between the heating means and the combustion tube in which cooking fumes are decomposed by the heat from the heating means, a fan adapted to withdraw air from the cooking cavity and to discharge a part or all of the air through the connection tube into the combustion space, a connection tube for connecting fluid communication between the combustion tube and the fan, and a gas outlet for venting the steam and air in the combustion space to the outside of the cooking device.

Description

[Field of the invention]

The present invention relates to a combustion device that can remove odor-producing materials in the cooking cavity. Specifically, the present invention relates to a heating means in the cooking cavity that can cause thermal decomposition of odor-producing materials, in addition to cooking the food by radiation of its heat.

[Description of related arts]

When food is heated in a cooking device, steam and volatile fumes are generated from the food. These volatile fumes may contain carcinogenic formaldehyde and a variety of toxic materials which may be harmful to human health. To minimize the adverse effects of using the cooking device, these toxic contaminants should be prevented from spreading into the living area of the user. Although range hoods are installed in many homes to vent cooking fumes, only a portion of the cooking fumes are discharged outside and the rest may diffuse into the kitchen and other living areas.
A number of different ways for disposing cooking fumes such as adsorption method using activated carbon filters, a combustion method, a catalytic converter method, an ionic precipitation method, and a plasma discharging method are well known. Among these, the combustion method is highly effective in removing cooking fumes, which are oxidized at high temperature to yield harmless carbon dioxide and water. Also, the combustion method is proven to be economical and reliable enough to be used for the incineration of toxic chemical and biological wastes.
Some of the cooking ovens have self-cleaning functions to cause pyrolysis at temperatures of about 400 - 500°C in order to remove food contaminants accumulated on the wall of the cooking cavity. However, the above case adopts a method of re-heating the cooking cavity after taking out the food and cannot solve the problem of diffusing fumes during cooking. Therefore, a device for effectively removing contaminants generated during cooking is desired.
To solve the above problems, the present invention provides cooking device for effectively removing cooking fumes in the cooking cavity. An object of the present invention is to provide an energy efficient combustion device which includes a heating means adapted to heat up food in the cooking cavity and to provide a cleaning effect. Another object of the present invention is to keep the user safe from the harmful cooking fumes by removing the fumes immediately as soon as they are generated in the cooking cavity.
The following patents are known in the art and are incorporated by reference herein: Korean Pat. Nos. 10-0518444 ; 10-0555420 , 10-1203444 ; and U.S. Pat. Nos. 6,316,749 ; 6,318,245 ; 7,878,185 ; 8,101,894 .

SUMMARY OF THE INVENTION

The cooking device with pyrolysis function includes a cooking cavity surrounded by cavity walls and an oven door, a heating means located within the cooking cavity for emitting heat therefrom, a combustion tube having a hollow portion formed to surround the heating means, the combustion tube being heated by the heating means and radiating its heat to the center of the cooking cavity, a combustion space formed between the heating means and the combustion tube in which cooking fumes are decomposed by the heat from the heating means, a fan adapted to withdraw air in the cooking cavity and to transfer a part or all of the air through the connection tube into the combustion space, a connection tube for connecting fluid communication between the combustion tube and the fan, and a gas outlet for venting out the steam and air in the combustion space to the outside of the cooking device.
The heating means located on the upper portion of the cooking cavity comprises any source selected from flame generated by the oxidation of fuel or a heater connected to power source.
The combustion tube has a hollow tube-type structure with a gas outlet formed at one end of the combustion tube and a combustion tube inlet formed at the opposite end where the heating means is connected. The heating means is enclosed by the combustion tube. A combustion space is formed between the heating means and the combustion tube. The combustion space and the combustion tube are heated by the heating means. When heated, the combustion tube radiates its heat to the center of the cooking cavity. The fumes generated during cooking are introduced to the combustion tube to be thermally decomposed. Therefore, high energy efficiency is achieved by the heating means which has the dual function of warming food via the combustion tube, which radiates its heat to the cooking cavity, as well as causing thermal decomposition of cooking fumes.
The fan receives power generated from a motor and forcibly convects the air within the cooking cavity. The fan is connected to the combustion tube through the connection tube and introduces the air and cooking fumes into the combustion space. The fan prevents the cooking fumes from spreading out of the cooking cavity by maintaining a lower-than-the-atmospheric pressure within the cooking cavity.
The connection tube is installed between the combustion tube and the fan and functions as a passage for a part or all of the air inhaled by the fan into the combustion space. It is desirable that the connection tube is connected to the combustion tube near the connection tube inlet, maximizing the contacting distance of cooking fumes with the heating means to improve the efficiency of the pyrolysis process.
The gas outlet is formed at one end of the combustion tube and functions as a passage for the steam and mixed gas in the combustion tube to the outside of the cooking device.
The cooking device further includes a temperature sensor for sensing the operating temperature of the cooking cavity, a bottom heating means adapted to warm the bottom portion of the cooking cavity, and an air supply adapted to accelerate the oxidation of cooking fumes by injecting air into the combustion space.
The combustion process of contaminants in the cooking cavity is as follows. When a heat source is supplied to the heating means to emit heat, the temperature of the combustion space and the combustion tube increases. As the food is warmed by the radiant heat from the combustion tube to the center of the cooking cavity, steam and fumes from the food are generated in the cooking cavity. The fan withdraws air and fumes in the cooking cavity, and transfer a part or all of the air and fumes through the connection tube into the combustion space. The cooking fumes undergo thermal decomposition (pyrolysis) in the combustion space maintained at 700°C or higher temperature, and become carbon dioxide and water. The mixed gas in the combustion space travels towards the gas outlet to be vented out of the cooking device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing a cooking device 10 according to the present invention.
FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1 .
FIG. 3 is a side sectional view taken along the line 3-3 of FIG. 2 .
FIG. 4 is a perspective view of some components showing a flow of air for thermal decomposition.

DETAILED DESCRIPTION OF THE INVENTION

The objects and features of the present invention will be now made in detail to the preferred embodiments of the present invention with reference to the attached drawings.
FIG. 1 is a front view showing a cooking device 10 according to the present invention. An oven door 25 having a door knob 28 is rotatably attached to an oven body 20 forming the outward appearance of the oven 10. The oven door 25 seals the front side of a cooking cavity 30 to prevent volatile compounds or smells from escaping from the cooking cavity 30, to make racks easily go in and out of the cooking cavity, and to allow a user to check the progress of cooking. A control panel 22 is disposed at one side of the front face of the oven body 20. The control panel 22 includes at least one controlling means for setting temperature and time so that the inside of the cooking cavity 30 can keep a preset temperature for an appropriate period of time.
FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1 showing the inside configuration of the cooking cavity 30 and the oven body 20, and FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2 . Referring to the drawings, the present invention will be described in detail as follows. The cooking cavity 30 is surrounded by a cavity wall 35 and has an open front face with an interior cooking space. The cooking cavity 30 further includes a heating means 50 mounted at the upper part of the cooking cavity 30 and a combustion tube 60 having a hollow portion formed to surround the heating means 50. The "upper part" indicates that the heating means 50 and the combustion tube 60 are located at the higher position than the center of the cooking cavity 30.
The combustion tube 60 has a hollow tube-type structure with a gas outlet 90 formed at one end of the combustion tube 60 and a combustion tube inlet 62 formed at the opposite end where the heating means 50 is connected. The heating means 50 comprises any heating source selected from a flame generated by the oxidation of fuel or a heater connected to a heat source 100. A combustion space 65 is formed between the heating means 50 and the combustion tube 60. The cooking fumes can undergo thermal decomposition (pyrolysis) in the combustion space 65 maintained at 700°C or higher by the heating means 50.
As the combustion tube 60 is heated by the heating means 50, the radiant heat of the combustion tube 60 is applied to the center of the cooking cavity 30 to warm the food. Therefore, it is preferable that the combustion tube 60 is configured to extensively circulate air in the upper portion of the cooking cavity 30 to effectively radiate its heat to the center of the cooking cavity 30.
The combustion tube 60 is selected from a group consisting of ceramics, heat-resisting metals, and a combination of both in order to withstand the heat generated by the heating means 50. It is preferable that the combustion tube 60 made of ceramics be enclosed by a heat resisting metallic cover (not shown) in order to protect it from external physical impacts.
The cooking cavity 30 further includes a fan 70 driven by a motor for forcibly convecting the air within the cooking cavity 30. The fan 70 is a centrifugal fan and is connected in fluid communication to the combustion tube 60. The fan 70 withdraws air from the cooking cavity and discharges a part or all of the air into the combustion space 65. When a part of the withdrawn air is discharged back into the cooking cavity 30, the air is forcibly convected around the hot combustion tube 60 resulting in a rapid increase of temperature in the cavity and cooking speed.
The fan 70 also prevents the cooking fumes from spreading out of the cooking cavity 30 by maintaining a lower than atmospheric pressure within the cooking cavity 30. It is possible that the amount of air introduced into the combustion space 65 to be controlled by the fan 70 to adjust the pressure of the cooking cavity 30. The amount of cooking fumes to be pyrolyzed can also be controlled.
The connection tube 80 is installed between the combustion tube 60 and the fan 70 and functions as a passage for a part or all of the air inhaled by the fan 70 into the combustion space 65. It is desirable that the connection tube 80 is connected to the combustion tube 60 near the connection tube inlet 62, maximizing the contacting distance of cooking fumes with the heating means 50 to improve the efficiency of the pyrolysis process.
The gas outlet 90 is formed at one end of the combustion tube 60 and functions as a passage for the steam and mixed gas in the combustion space 65 to the outside of the cooking device 10.
An air supply 68 and heat source 100 are installed at the connection tube inlet 62. The air supply 68 provides fresh air into the combustion space 65 to accelerate the oxidation of cooking fumes. The air supply 68 also provides fresh air required for the oxidation of fuel in the case the heating means 50 comprises a flame. The heat source 100 comprises any source selected from fossil fuel or a wire connected to a power source.
The cooking device 10 further includes a bottom heating means 55 adapted to warm the bottom portion of the cooking cavity 30 and expedite the cooking of the food. The bottom heating means 55 comprises any heating source selected from flame generated by the oxidation of fuel or a heater connected to power source. It is desirable that the bottom heaing means 55 be located outside of the cooking cavity 30 as illustrated in FIG. 3 if the bottom heating means 55 comprises a flame. In the case the bottom heating means 55 comprises a heater, it is preferred that the bottom heating means 55 be installed inside of the cooking cavity 30.
The cooking device 10 further includes a temperature sensor 40 for sensing the operating temperature of the cooking cavity 30. Located at the cavity wall 35, the temperature sensor 40 detects the changes of temperature in the cooking cavity 30 and may turn off the operation of the heating means 50 or the bottom heating means 55 in the case the cooking cavity 30 is significantly above the preset temperature.
FIG. 4 is a perspective view of some components showing a flow of air for thermal decomposition. Referring to the drawings, the combustion process of contaminants in the cooking cavity will be described in detail as follows.
When the heat source 100 is supplied to the heating means 50 to emit heat, the temperature of the combustion space 65 and the combustion tube 60 increases. As the food is warmed by the radiant heat from the combustion tube 60 to the center of the cooking cavity 30, steam and fumes from the food are generated in the cooking cavity 30. The fan 70 withdraws air and fumes from the cooking cavity 30 and discharges a part or all of the air and fumes through the connection tube 80 into the combustion space 65. The cooking fumes undergo thermal decomposition (pyrolysis) in the combustion space 65 maintained at 700°C or higher temperature and become carbon dioxide and water. The mixed gas in the combustion space 65 travels towards the gas outlet 90 to be vented out of the cooking device 10. During the preset cooking time, the heating means 50 and the fan 70 are turned on so as to thermally decompose the contaminants generated during cooking. The combustion cycle comes to an end when the heat source 100 to the heating means 50 and electricity to the fan 70 is terminated.
As described above for the pyrolysis process of the cooking fumes, the cooking device 10 according to the present invention is efficient in use of energy because the heating means 50 has the dual function of warming food via the combustion tube 60, which applies its radiant heat to the cooking cavity 30, as well as causing the thermal decomposition of the cooking fumes.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

LIST OF NUMERALS

10: Cooking device	20: Oven body
22: Control means	25: Oven door
28: Door knob	30: Cooking cavity
35: Cavity wall	40: Temperature sensor
50: Heating means	55: Bottom heating means
60: Combustion tube	62: Combustion tube inlet
65: Combustion space	68: Air supply
70: Fan	80: Connection tube
90: Gas outlet	100: Heat source

Claims

A cooking device comprising:
a cooking cavity surrounded by cavity walls and an oven door;

a heating means located within the cooking cavity for emitting heat therefrom;

a combustion tube having a hollow portion formed to enclose the heating means, the combustion tube being heated by the heating means and radiates its heat to the center of the cooking cavity;

a combustion space formed between the heating means and the combustion tube in which cooking fumes are decomposed by the heat from the heating means;

a fan adapted to withdraw air from the cooking cavity and to discharge a part or all of the air through the connection tube into the combustion space;

a connection tube for connecting fluid communication between the combustion tube and the fan; and

a gas outlet for venting the steam and air in the combustion space to the outside of the cooking device.
The cooking device of claim 1, wherein the heating means has the dual function of warming food via the combustion tube, which applies radiant heat to the cooking cavity, as well as causing thermal decomposition of cooking fumes.
The cooking device of claim 1, wherein the fan prevents the cooking fumes from spreading out of the cooking cavity by maintaining a lower-than-the-atmospheric pressure within the cooking cavity.
The cooking device of claim 1, wherein the heating means comprises any heating source selected from a flame generated by the oxidation of fuel or a heater connected to the heat source.
The cooking device of claim 1, wherein the combustion tube is selected from a group consisting of ceramics, heat-resisting metals, and a combination of ceramics and heat-resisting metals.
The cooking device of claim 1, further comprising an air supply adapted to inject fresh air into the combustion space.
The cooking device of claim 1, wherein the connection tube is connected to the combustion tube near the connection tube inlet, maximizing the contacting distance of cooking fumes with the heating means to improve the efficiency of the pyrolysis process.
The cooking device of claim 1, wherein the fan is a centrifugal fan.
The cooking device of claim 1, further comprising a temperature sensor for sensing the operating temperature of the cooking cavity.
The cooking device of claim 1, wherein the amount of air introduced into the combustion space is controlled by the fan to adjust the pressure of the cooking cavity or the amount of cooking fumes to be pyrolyzed.
The cooking device of claim 1, wherein the combustion tube is located at the higher position than the center of the cooking cavity.
The cooking device of claim 1, further comprising a bottom heating means adapted to warm the bottom portion of the cooking cavity.
The cooking device of claim 12, wherein the bottom heating means comprises any heating source selected from flame generated by the oxidation of fuel or a heater connected to power source.