WO2008086564A1

WO2008086564A1 - A burner assembly

Info

Publication number: WO2008086564A1
Application number: PCT/AU2008/000033
Authority: WO
Inventors: Peter Woodland
Original assignee: Woodland Home Products Pty Ltd
Priority date: 2007-01-15
Filing date: 2008-01-14
Publication date: 2008-07-24
Also published as: AU2008207331A1

Abstract

A burner assembly for a grill, comprising a perforated ceramic plate, which has a plurality of first apertures therein. The ceramic plate is fitted to a burner body, and a vaporiser for evaporating greases, which has a plurality of second apertures therein. The average size of the first apertures in the ceramic plate is substantially greater than the average size of the second apertures in the vaporiser.

Description

A BURNER ASSEMBLY

TECHNICAL FIELD

The present invention relates to a burner assembly for a grill, and in particular a grill comprising a ceramic burning plate.

BACKGROUND ART

Gas grills for cooking food are well known. Cooking on grills such as barbeque grills generally is done by heating ceramic briquettes or various types of metal surfaces. Typically the heat source is propane, natural gas or charcoal.

Conventional grills include ceramic briquettes or "lava rocks" designed to be heated by burning the gas or fuel to radiate heat. One such conventional grill is described in United States Patent No. US 4,321,857 (Best). Such ceramic briquettes used in conventional grills tend to generate little infrared energy and possess poor thermal inertia. As a result of the poor thermal inertia of the briquettes, as liquids impinge and evaporate on the surface of the briquettes, the briquettes are cooled below the ignition temperature of the oils that drip from the food onto the briquettes. As oils and/or liquids drip from the food, they tend to be absorbed into the ceramic briquettes and build up on the briquettes, which overtime buildup and can ignite and cause flame flare ups. Accordingly, such ceramic briquettes generally have to be changed at periodic intervals.

Some conventional grills utilize metal plates that are impinged and heated by the flames and products of combustion. Such metal plates, however, are also poor emitters of infrared radiation, and generally are used, as with the ceramic briquettes, for the purpose of evaporating juices and incinerating fats that fall upon them from the cooking meats to create vapors that are then directed over the surfaces of the food to impart an "outdoor" or smoked flavor.

Attempts have been made in the past to overcome the problems identified above.

Gas grills have been developed which utilize under-fired burner assemblies designed specifically to generate infrared radiant energy for cooking food. For example, United States Patent No's US 4,321,857 (Best) and US 4,886,044 (Best) disclose infrared gas grills,, which cook food using infrared radiant energy. However, one problem with conventional under-fired infrared grills is that generally these devices can have a low level of thermal inertia or have a heating element that is positioned out of contact with the juices and fats that drip from the meat or other food being cooked. This can result in the juices and fats that are released from the food during cooking not being vaporized or burned to create vapors that pass over the food to impart flavor. Additionally, in conventional under-fired infrared grills, the juices and fats that may drip from the meat or other food being cooked can clog the

^• openings of the burner in which the gas escapes.

One such example that attempted to overcome the identified problems of conventional under-fired infrared grills is United States Patent No. US 6,114,666 (Best), which describes a gas grill that utilises an under-fired burner assembly designed specifically to generate infrared radiant energy for cooking food. The burner described in US 6,114,666 comprises a heating assembly mounted to a burner wherein the heating assembly includes an infrared radiant energy emitter positioned above the burner. The infrared emitter is composed of glass/ceramic material. The infrared emitter absorbs heat energy generated within the burner in the form of convective heat energy, conducted heat energy, infrared radiant energy or a combination thereof. This causes the infrared emitter to be heated to high temperatures, in the range of between 150⁰C to 730⁰C, and over a full range of operating temperatures in between. Approximately 85% of the heat energy absorbed by the infrared emitter is re-radiated due to its own temperature and emissivity at longer wavelengths than that of the absorbed energy. The remaining radiant energy that is absorbed by the infrared emitter is transmitted directly through the glass material of the infrared emitter.

It is therefore an object of the present invention to provide a fertiliser which goes at least some way towards overcoming or at least minimising the prior art problems or limitations outlined above or at the very least providing a suitable alternative to presently known grills comprising a ceramic burning plate.

DISCLOSURE OF THE INVENTION

According to a first aspect the present invention consists of a burner assembly for a grill comprising a perforated ceramic plate having a plurality of first apertures therein. The ceramic plate is fitted to a burner body. A vaporiser for evaporating greases, which has a plurality of second apertures therein is also part of the grill. The average size of the first apertures in the ceramic plate is substantially greater than the average size of the second apertures in the vaporiser. Preferably, the second apertures in the vaporiser are less than half the size of the first apertures in the ceramic plate.

The density of second apertures in the vaporiser is preferably 110 apertures/cm² and the combined total surface area of each of the second apertures in the vaporiser is 22% of the total surface area of the vaporiser.

Preferably, each of the second apertures in the vaporiser are substantially circular and the average diameters of each of the second apertures in the vaporiser is 0.5mm.

The vaporiser preferably has a profile of constant cross-section, and is an inverted V-shaped member including an apex and two free ends. Preferably, the two free ends of the vaporiser extend from the apex at an angle of 45°. Given the slope of the vaporiser at an angle of 45°, the effective size of each of the second apertures in the vaporiser in a vertical direction is less than 0.5mm.

Preferably, the density of first apertures in the ceramic plate is 35.75 apertures/cm² and each of the first apertures in the ceramic plate are substantially circular. The average diameter of each of the first apertures in the ceramic plate is 1.35mm. The first apertures in the ceramic plate are set in staggered rows spaced 1.6mm apart and adjacent first apertures in each of the staggered rows in the ceramic plate are set 1.9mm apart.

The vaporiser is one piece and is substantially composed of a heat conductive material, which is preferably metal and most preferably stainless steel.

BRIEF DESCRIPTION OF DRAWINGS

A preferred embodiment of the invention will now be described by way of example only, with reference to the accompanying figures in which:

FIG 1 is a perspective view of the burner assembly for a grill according to a first aspect of the present invention.

FIG 2 is an end cross-sectional view of the burner assembly for a grill as depicted in FIG 1.

FIG 3 is a perspective view of the vaporizer component of the burner assembly for a grill as depicted in FIG 1.

FIG 4 is an enlarged perspective view of the ceramic plate component of the burner assembly for a grill depicted in FIG 1. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention generally consists of a burner assembly for a grill, and in particular a grill comprising a ceramic burning plate. Referring to FIGS 1 and 2, there is shown a burner assembly 1 having a burner body 2, a ceramic plate 3 and a vaporiser 4. The ceramic plate 3 is located between the burner body 2 and the vaporiser 4. Gas, such as LPG or natural gas, is fed through the burner body 2 and then escapes through each of the apertures 5 of the ceramic plate 3, where the gas is ignited and burnt. The gas is initially ignited by a spark and once the gas begins to burn, the steady supply of gas fuels the flame. In this way, the ceramic plate 3 is heated and serves to cook food on the grill using infrared radiant energy.

As best shown in FIGS 1 and 3, the vaporiser 4 is an inverted V-shaped member that has an apex 7 and two free ends 8. The angle between the two free ends 8 of the vaporiser 4 is approximately 90°. The vaporiser 4 is composed of a metallic heat conductive material such as stainless steel. The vaporiser 4 is composed of a single piece and has a plurality of apertures 6 therein.

FIG 4 shows the ceramic plate 3 having a plurality of apertures 5 therein. The apertures 6 in the vaporiser 4 are substantially smaller than the apertures 5 in the ceramic plate 3. This ensures that even if particles, such as, juices, fats and the like drop from the food being cooked on the grill are able to fall through the apertures 6 in the vaporiser 4, these particles will not be of a sufficient size to clog or block the apertures 5 in the ceramic plate 3.

Both the apertures 6 in the vaporiser 4 and the apertures 5 in the ceramic plate 3 are substantially circular. The density of apertures 6 in the vaporiser 4 is 110 apertures/cm², which equates to a combined total surface area of approximately 22% of the total surface area of the vaporiser. Each one of the apertures 6 in the vaporiser 4 has a diameter of approximately 0.5mm. Due to the 90° angle between the free ends 8 of the vaporiser 4, the effective diameter in the vertical direction of each of the apertures 6 in the vaporiser is reduced to be less than their actual width of 0.5mm. The inverted V-shape of the vaporiser 4 helps to reduce the possibility of the apertures 5 in the ceramic plate 3 being clogged or blocked. This is because the inverted V- shape directs particles of food and the like away from the ceramic plate 3 and the burner body 2.

The density of apertures 5 in the ceramic plate 3 is 35.75 apertures/cm². Each one of the apertures 5 in the ceramic plate 3 has a diameter of approximately 1.35mm. The apertures 5 in the ceramic plate 3 are arranged in rows on the ceramic plate 3. Each one of the apertures 5 is located approximately 1.9mm from adjacent apertures in the same row and there is a distance of approximately 1.6mm between each row of apertures on the ceramic plate 3.

Whilst in the preferred embodiment the vaporiser 4 is composed of stainless steel, it should be understood that in other embodiments the vaporiser could be composed of any other suitable type of heat conductive material.

It should also be understood that in other embodiments not shown in the drawings, the apertures 5 in the ceramic plate 3 and the apertures 6 in the vaporiser 4 can be of different shapes and sizes than those described above.

A person skilled in the art would understand that the measurements and dimensions of the apertures 5 and 6 as described above are only preferred measurements and any suitably sized apertures can be used within the scope of this invention.

In other embodiments, not shown in the drawings, the apertures 5 in the ceramic plate 3, as well as the apertures 6 in the vaporizer 4, can be arranged in configurations other than in straight rows. The apertures can be randomly arranged or can be arranged in concentric circular patterns or any other suitable configurations.

It will be apparent that obvious variations or modifications may be made which are in accordance with the spirit of the invention and which are intended to be part of the invention, and any such obvious variations or modifications are therefore within the scope of the invention.

In this specification, unless the context clearly indicates otherwise, the term "comprising" has the non-exclusive meaning of the word, in the sense of "including at least" rather than the exclusive meaning in the sense of "consisting only of". The same applies with corresponding grammatical changes to other forms of the word such as "comprise", "comprises" and so on.

Claims

1. A burner assembly for a grill comprising a perforated ceramic plate having a plurality of first apertures therein, said ceramic plate being fitted to a burner body, and a vaporiser for evaporating greases having a plurality of second apertures therein, wherein the average size of the first apertures in said ceramic plate is substantially greater than the average size of the second apertures in said vaporiser.

2. The burner assembly for a grill of claim 1 wherein the second apertures in the vaporiser are less than half the size of the first apertures in the ceramic plate.

3. The burner assembly for a grill of claim 1 wherein the density of second apertures in the vaporiser is 110 apertures/cm².

4. The burner assembly for a grill of claim 3 wherein the combined total surface area of each of the second apertures in the vaporiser is 22% of the total surface area of the vaporiser.

5. The burner assembly for a grill of claim 1 wherein each of the second apertures in the vaporiser are substantially circular.

6. The burner assembly for a grill of claim 5 wherein the average diameters of each of the second apertures in the vaporiser is 0.5mm.

7. The burner assembly for a grill of claim 1 wherein the vaporiser has a profile of constant cross-section.

8. The burner assembly for a grill of claim 7 wherein the vaporiser is an inverted V-shaped member including an apex and two free ends.

9. The burner assembly for a grill of claim 8 wherein the two free ends of the vaporiser extend from the apex at an angle of 45°.

10. The burner assembly for a grill of claim 8 wherein because of the slope of the vaporiser at an angle of 45°, the effective size of each of the second apertures in the vaporiser in a vertical direction is less than 0.5mm.

11. The burner assembly for a grill of claim 1 wherein the density of first apertures in the ceramic plate is 35.75 apertures/cm².

12. The burner assembly for a grill of claim 1 wherein each of the first apertures in the ceramic plate are substantially circular.

13. The burner assembly for a grill of claim 12 wherein the average diameters of each of the first apertures in the ceramic plate is 1.35mm.

14. The burner assembly for a grill of claim 1 wherein the first apertures in the ceramic plate are set in staggered rows spaced 1.6mm apart.

15. The burner assembly for a grill of claim 14 wherein adjacent first apertures in each of the staggered rows in the ceramic plate are set 1.9mm apart.

16. The burner assembly for a grill of claim 1 wherein said vaporiser is substantially composed of a heat conductive material.

17. The burner assembly for a grill of claim 16 wherein said conductive material is metal.

18. The burner assembly for a grill of claim 17 wherein said conductive material is stainless steel.

19. The burner assembly for a grill of claim 1 wherein said vaporiser is composed of one piece.