BAKING OVEN AND GAS BURNER DEVICE, PARTICULARLY FOR A BAKING OVEN

Abstract

A gas burner device for heating an interior chamber of a household appliance includes at least one burner tube including a profiled support section and a gas outlet plate connected to the profiled support section. The gas outlet plate includes holes configured for gas discharge therethrough. The gas burner device may be implemented in a baking oven or a range.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No. EP 09 401 049.3, filed on Dec. 14, 2009, which is hereby incorporated by reference herein in its entirety.

FIELD

The present invention relates to a gas burner device for heating an interior chamber of a household appliance, and to a household appliance equipped with such gas burner device.

BACKGROUND

Gas burners are used to heat the interior chamber of a baking oven by the energy released during the combustion of gas. Typically, gas burners have pipe-shaped gas burner tubes, which are provided with flame ports through which the gas to be burned is emitted.

European Patent EP 0 860 658 B1 describes a gas-fired baking oven, in which the gas burner tube has laterally arranged flame ports. Various methods are commonly used are for producing the gas burner tubes and forming the flame ports therein.

One problem involved in the production of burner tubes is that holes of approximately elliptical cross-section are formed at the radial bends of the burner tube. This results in an uneven flame distribution around the periphery of the burner tube, which in turn results in an uneven heat distribution in the baking oven.

Elliptical cross-sections occur when tubes having circular holes are bent. The originally circular holes become distorted in the region of the bend and assume an elliptical cross-section.

In order to obtain perfectly round holes as flame ports, the holes may be formed by burning with a laser. However, this method is complex and expensive. In addition, the laser continues to drill, i.e., to emit, after a desired hole is completed and, therefore, may damage the material located therebehind. Preventing this is difficult and requires considerable technical effort and time. Mechanical drilling of the holes is also complex and very time-consuming and, therefore, does not lead to better results from an economic point of view.

SUMMARY

In an embodiment, the present invention provides a gas burner device for heating an interior chamber of a household appliance. The gas burner device includes at least one burner tube including a profiled support section and a gas outlet plate connected to the profiled support section. The gas outlet plate includes holes configured for gas discharge therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention is described below with reference to the drawings, in which:

FIG. 1 shows a range with the cooking chamber open;

FIG. 2 shows the open cooking chamber with a gas burner device inserted therein;

FIG. 3 is a top view of an installed gas burner device; and

FIG. 4 is a side view of an installed gas burner device.

DETAILED DESCRIPTION

In an embodiment, the present invention provides a gas burner device for heating an interior chamber of a household appliance, and a household appliance equipped therewith, which are less expensive to manufacture than conventional alternatives, making it possible to achieve a uniform burning behavior.

The gas burner device according to the present invention may be used to heat an interior chamber of a household appliance, such as a baking oven. In an embodiment, the gas burner device includes at least one burner tube including at least one profiled support section and at least one gas outlet plate connected thereto, the gas outlet plate having holes formed therein to allow gas to be discharged therethrough.

This design makes it possible to produce and store the profiled support section and gas outlet plate separately. The profiled support section may be manufactured to have a greater sheet thickness than the gas outlet plate, which allows for cost savings. Separate manufacture is also possible. This can provide further savings in material and costs.

The holes in the gas outlet plate may be formed by punching. This allows even gas outlet plates having a multiplicity of holes to be produced in a cost-effective manner with high accuracy and at high production rates. Moreover, the holes formed in a plate may differ in size and geometry.

The profiled support section can be connected in a gas-tight manner to the at least one gas outlet plate. Gas-tight connections ensure a uniform supply. This connection can be made by welding or edge crimping. A screwed connection between the profiled support section and the at least one gas outlet plate is also possible, but may require the use of seals. The connection should be permanently gas tight, even at the temperatures occurring during operation.

The profiled support section can be designed as a top-hat rail, with the gas outlet plate being in the form of a flat sheet metal plate. In an embodiment, the top-hat rail takes the form of a U-shaped section having two flat contact surfaces. The contact surfaces allow the gas outlet plate to lie or rest thereagainst. Because of this construction, the gas outlet plate can be easily positioned on the profiled support section, which is advantageous for the production process. Additional production steps can thus be carried out much more easily. Providing the gas outlet plate in the form of a flat sheet metal plate makes it inexpensive to purchase and facilitates the punching of the holes considerably.

The gas outlet plate and the profiled support section can be of different sheet thicknesses. Different sheet thicknesses are possible because of the different thermal and mechanical loads, and allow for cost optimization. The profiled support section can have a slightly greater wall thickness and also serves to provide stability, while the gas outlet plate may be very thin.

In particular, the gas outlet plate can have a thickness of about 0.2 mm to about 1.0 mm Preferably, the thickness is between 0.3 mm and 0.7 mm In a particular, the gas outlet plate can have a thickness of 0.4 mm to 0.6 mm

An advantage of the small sheet thickness of the gas outlet plate is its positive effect on the flame pattern.

The gas outlet plate can be, in some sections, adapted to the outer contour of the profiled support section by bending.

Even in the case of a thin gas outlet plate, the originally circular holes can become distorted in the bent regions. The previously circular shape of the holes changes slightly to a somewhat noncircular shape. However, the degree of distortion is dependent on the sheet or wall thickness. If the thickness of the gas outlet plate is small, this effect is very small and hardly noticeable.

In contrast to conventional gas tubes, where large wall thicknesses lead to strongly elliptical holes, the flame ports of a burner tube according to embodiments of the present invention can be much more uniform in shape, so that a uniform flame pattern can be achieved.

The gas discharge from strongly elliptical holes differs from that of circular holes. In the case of elliptical holes, an uneven flame may be produced, and an irregular flame pattern may be produced around a periphery of the gas outlet plate. In embodiments of the present invention, this effect can be virtually completely avoided. In contrast, when bending a finished tube, significantly greater distortions will occur as a result of the wall thickness.

In baking ovens, a defined and reproducible flame pattern is important because a non-defined flame pattern may give rise to incomplete combustion, during which even toxic carbon monoxide may be formed.

The gas burner tube of an embodiment of the present invention can be designed as a closed ring, which may be substantially rectangular. This configuration is advantageous because most baking ovens are square or rectangular in cross-section. Alternatively, it is possible to design gas burner tubes as a ring of substantially circular or elliptical shape.

The gas burner device has holes formed in the gas outlet plate. These holes can be arranged in rows on the gas outlet plate. In an embodiment, two rows are arranged parallel to each other.

The holes in the gas outlet plate have predefined dimensions. The dimensions of the holes can be approximately equal within the limits of manufacturing accuracy. The holes of a lower row can have a smaller diameter than the holes of an upper row. During ignition, the holes of the smaller diameter contribute to ensure that the flames propagate along a circular path. Moreover, in the event that an upper flame is extinguished, the holes of the smaller diameter ensure rapid re-ignition of this upper flame.

The holes of the lower row can be vertically offset from the holes of the upper row. This arrangement allows the gas discharged from the upper holes to be ignited into flames by means of the smaller holes.

The gas burner device can have a central gas supply through which gas is supplied to the gas burner tube. In addition to an ignition device, the gas burner device may also have a device for monitoring the flame temperature as well as a gas outflow sensor. The gas outflow sensor can issue a visual and an audible alarm when outflowing gas is not burned. The combined alarm is advantageous for use in kitchens which are used by people with sensory impairments, such as poor eyesight or poor hearing Optionally, this sensor may be provided with a wireless monitoring feature for alarm signaling. This can be helpful if the user cannot stay in the kitchen during the entire cooking time.

In an embodiment, the household appliance of the present invention is used, in particular, as a baking oven and has at least one heatable interior chamber. At least one gas burner device is provided for heating the at least one interior chamber. The gas burner device includes at least one burner tube, said burner tube including at least one profiled support section and at least one gas outlet plate connected thereto. The gas outlet plate has holes formed therein to allow gas to be discharged therethrough.

FIG. 1 shows a household appliance, here in the form of a range 1, with a cooking chamber 2 in an open state. Bottom surface 3 of the oven chamber is approximately rectangular in cross section. A gas burner device according to the present invention is located below bottom surface 3. A convection fan 5 is disposed in the rear 4 of the cooking chamber. Four separate gas-powered cooking zones 16 are provided on top of this appliance. Other embodiments may have radiant cooking zones or induction cooking zones. Control knobs 17 arranged on a control panel are used for selectively controlling cooking zones 16 and setting the temperature in cooking chamber 2.

FIG. 2 shows, in a schematic exploded view, range 1 and gas burner device 6 installed therein. At front 7, bottom surface 3 of cooking chamber 2 is shown in cross section. Clearly discernible is a line 8 for central gas supply, as well as burner tube 9. Burner tube 9 includes a profiled support section 10 (i.e., a profiled base section) and a gas outlet plate 11. A convection fan 5 is installed in rear wall 12 of cooking chamber 2, said convection fan conveying the heated air as convection air from the area of the gas burner tube 11 into the area of cooking chamber 2.

Gas outlet plate 11 has holes 13, which are also referred to as flame ports. Holes 13 are formed by punching. Profiled support section 10 is connected at least to gas outlet plate 11, here in particular by welding. This design allows even burner tubes 9 of complex geometry to be manufactured in a simple manner.

In an embodiment, profiled support section 10 is designed as a top-hat rail, and gas outlet plate 11 is in the form of a flat sheet metal plate. The combination of the top-hat rail and the flat sheet metal plate is also advantageous for the manufacture of burner tube 9, because it significantly facilitates the fixing of gas outlet plate 11 to profiled support section 10. Gas outlet plate 11 and profiled support section 10 are connected in a gas-tight manner, for example by welding or edge crimping.

FIG. 3 shows, in a cross-sectional top view, a gas burner device 6 installed in a baking oven 2. Burner tube 9 is substantially rectangular in shape with rounded corners, and is designed as a closed ring. Gas is supplied centrally through line 8. The illustration shows that an additional burner tube 9 could be placed, for example, in inner region 14 surrounded by burner tube 9. This option may be of interest for use in commercial kitchens, where speed is also of primary concern.

FIG. 4 shows a cross-sectional side view through burner tube 9 in the left portion, and a front view of gas outlet plate 11 in the right portion. Profiled support section 10 takes the form of a top-hat section. The top-hat section has contact surfaces 15 on the upper and lower flanges. Contact surfaces 15 allow gas outlet plate 11 to be quickly and easily secured to profiled support section 10 for the welding operation, for example, by means of a C-clamp. In the side view, profiled support section 10 and gas outlet plate 11 are shown separated from each other. This representation was chosen to allow the shapes of profiled support section 10 and gas outlet plate 11 to be shown with more definition.

Gas outlet plate 11 and profiled support section 10 are made in different sheet thicknesses. Gas outlet plate 11 has a thickness of 0.2 mm to 1.0 mm In a preferred embodiment, gas outlet plate 11 has a thickness between about 0.3 mm and about 0.7 mm

This allows the profiled support section 10 to be made sturdier for load-bearing purposes, while gas outlet plate 11 may be optimized for a homogeneous gas discharge and a homogeneous flame pattern. Profiled support section 10 is subjected to a combined, predominantly thermomechanical stress, while gas outlet plate 11 is predominantly subjected to the thermal component.

Holes 13 are arranged on gas outlet plate 11. Preferably, holes 13 are arranged in two rows on gas outlet plate 11. In an embodiment, the rows are arranged parallel to each other. Holes 13 have predefined, equal dimensions. In an embodiment, the holes 13 are circular in shape and of a defined diameter, holes 13 of a lower row having a smaller radius than holes 13 of an upper row.

Alternatively to the representation in FIG. 4, the gas outlet plates could also be configured to have three or more rows of holes. In such constructions, analogously to FIG. 2, the holes 13 having the smallest diameter are arranged in the lowermost row.

Here, holes 13 of the lower row are vertically offset from holes 13 of the upper row.

Holes 13 of smaller radii, which are located in the lower row, serve firstly as a safety row to ensure that the flames propagate along a circular path during ignition. Secondly, in the event that an upper flame is extinguished, the row serves to quickly re-ignite this flame.

The small sheet thickness of gas outlet plate 11 described earlier herein provides an advantage in the curved sections of burner tube 9. When bending thick plates, the holes in the curved regions assume an approximately elliptical cross-section because of the deformation process. The ellipticity of the shape depends on the sheet thickness and a radius of curvature. Due to the small sheet thicknesses of gas outlet plate 11, the above-described effect is hardly noticeable here.

The geometry of holes 13 of gas outlet plate 11 plays an important role for the local flame formation. When the originally circular holes 13 become elliptical in shape, this may result in the formation of an uneven flame and an irregular flame pattern. A defined flame pattern is important, inter alia, for uniform heating and complete combustion.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

LIST OF REFERENCE NUMERALS

1 range

2 baking oven

3 bottom surface

4 rear

5 convention fan

6 gas burner device

7 front

8 line

9 burner tube

10 profiled support section/profiled base section

11 gas outlet plate

12 rear wall

13 holes, flame ports

14 inner region

15 contact surface

16 heating zone

17 control knob

Claims

1. A gas burner device for heating an interior chamber of a household appliance, the gas burner device comprising:

at least one burner tube including a profiled support section and a gas outlet plate connected to the profiled support section, the gas outlet plate including holes configured for gas discharge therethrough.

2. The gas burner device recited in claim 1, wherein the holes are punched in the gas outlet plate.

3. The gas burner device recited in claim 1, wherein the profiled support section is connected to the gas outlet plate by a gas-tight connection.

4. The gas burner device recited in claim 1, wherein the profiled support section is a top-hat rail.

5. The gas burner device recited in claim 4, wherein the gas outlet plate is a flat sheet metal plate.

6. The gas burner device recited in claim 6, wherein the gas outlet plate and the profiled support section have different respective thicknesses.

7. The gas burner device recited in claim 1, wherein the gas outlet plate has a thickness in a range of 0.2 mm and 1.0 mm

8. The gas burner device recited in claim 7, the thickness is in a range of 0.3 mm and 0.7 mm

9. The gas burner device recited in claim 1, wherein the at least one gas burner tube forms a closed ring.

10. The gas burner device recited in claim 9, wherein the closed ring is substantially rectangular.

11. The gas burner device recited in claim 1, wherein the holes have predefined, equal dimensions.

12. The gas burner device recited in claim 1, wherein the holes are disposed in a lower row and an upper row, the holes of the lower row being smaller than the holes of the upper row.

13. The gas burner device recited in claim 12, wherein the holes are substantially circular, each having a defined diameter, and wherein the holes of the lower row have a smaller diameter than the rows of the upper row.

14. The gas burner device recited in claim 12, wherein the holes of the lower row are vertically offset from the holes of the upper row.

15. The gas burner device recited in claim 1, further comprising a central gas supply connected to the at least one burner tube.

16. The gas burner device recited in claim 1, wherein the household appliance is at least one of a baking oven and a range

17. A household appliance comprising:

a cooking chamber; and

a gas burner device configured to heat the cooking chamber, the gas burner device including at least one burner tube having a profiled support section and a gas outlet plate connected to the profiled support section, the gas outlet plate including holes configured for gas discharge therethrough.

18. The household appliance recited in claim 17, wherein the appliance is at least one of a baking oven and a range.

19. The household appliance recited in claim 17, wherein the profiled support section is a top-hat rail and the gas outlet is a flat sheet metal plate.

20. The household appliance recited in claim 17, wherein the at least one burner tube forms a closed ring.

21. The household appliance recited in claim 17, wherein the holes are disposed in a lower row and an upper row, the holes of the lower row being smaller than the holes of the upper row.