AU2002314564B2 - Gas Burner Assembly - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): COINTECH AUSTRALIA PTY LTD Invention Title: GAS BURNER ASSEMBLY The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 GAS BURNER ASSEMBLY Field of the Invention This invention relates to a gas burner assembly and, in particular, to such a burner assembly for outdoor cooking appliances.

However, the burner can be used indoors or in other environments in which gas fuel is combusted to produce a flame.

Background Art Conventional gas burner assemblies, in particular those used for indoor and outdoor cooking appliances which are intended to heat the contents of a pot or the like, generally comprise a gas burner having a burner head from which gas can exit. The gas is burnt with combustion air in order to produce a flame for heating the pot and therefore, the contents within the pot. Generally the gas burner is exposed to the outside environment and a spider is arranged slightly above the gas burner on which the pot is supported.

This type of gas burner has been used in indoor cooking appliances for many years. This type of gas burner has also more recently found use in outdoor cooking appliances in which the burner is used on its own or beside a gas barbecue plate to provide an additional choice in the manner in which food is cooked in an outdoor environment.

Gas fuelled barbecue plates which are conventionally used outdoors generally operate satisfactorily because barbecue plates are usually large and therefore the flame produced by the gas burner does not spread to the periphery of the plate. Thus, the flame is not, to any great extent, exposed to the outside environment. However, gas burners which are intended to heat the contents of a pot are \\melb_files\home$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 3 completely exposed to the outside environment and this results in a number of significant problems.

The first problem associated with conventional gas burners which are intended to heat the contents of a pot is that the gas flame is easily extinguished by wind. This therefore requires the gas burner to be reignited or, if the fact that the gas burner has been extinguished is not noticed, results in the contents of the pot not being cooked. Furthermore, if the gas burner is used in windy conditions, even if the gas flame does not extinguish, the wind can tend to push the flame sideways so that it does not impinge on the bottom of the pot, thereby resulting in the contents of the pot not being cooked or considerably extending the cooking time, because most of the heat is directed away from the pot rather than to the bottom of the pot.

A second problem associated with outdoor gas burners is that in sunlight, the gas flame produced by the gas burner is virtually invisible. This can result in a severe hazard because, if a person reaches over the gas burner without realising the gas burner is ignited, severe burns can result.

Furtherstill, the fact that the flame produced by the gas burner is exposed to the outside atmosphere represents a fire hazard because paper or other combustible material in the vicinity of the gas burner can be blown across the exposed flame, which can ignite the paper, and then to the surrounding environment of the cooking appliance, which may cause a fire.

In view of the safety problems which are associated with conventional gas burners and also the reliability of such burners, conventional gas burners have found only limited use in outdoor cooking appliances and, in particular, in \\melbfiles\home$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 4 public grounds which are administered by local councils and the like, because of the possibility of injury to users and the possibility of fires.

Summary of the Invention The object of the present invention is to provide a gas burner assembly which overcomes these problems and therefore provides a gas burner assembly which is reliable in use and does not present a significant safety hazard from the point of view of burning users or creating fires.

The invention may be said to reside in a gas burner assembly including: a combustion tube for receiving a gas burner which has a burner head at which a flame is to be established, the combustion tube having a top end arranged above the burner head of the gas burner when the gas burner is located in the tube; an air inlet for allowing air to enter the tube, the air inlet being located below the burner head of the gas burner when the gas burner is located in the tube; a top cap having an upper surface arranged over the top end of the tube; a peripheral chamber extending about the top end of the tube; an air and combustion gas outlet located above the burner head of the gas burner when the gas burner is located in the combustion tube, for communicating the combustion tube with the chamber; an air inlet in the peripheral chamber adjacent the combustion tube; and an outlet opening in the peripheral chamber remote from the combustion tube.

According to the present invention, when a flame is established at the burner head, the combustion tube confines the flame generally to the region of the \\melb.files\homeS\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 5 combustion tube. Air to support combustion is allowed to enter the tube through the air inlet into the combustion tube so that combustion at the combustion end tends to draw air upwardly through the inlet to the combustion head. The combustion gases and any unburnt air is able to exit the tube through the air and combustion gas outlet.

Air entering the air inlet into the chamber adjacent the tube has the effect of cooling the combustion gases which exit the combustion gas outlet and also provides an air barrier to any flame which tends to spread from the tube to the peripheral chamber through the outlet so that the hot region of the burner assembly is confined to the vicinity of the tube and the air and combustion gas outlet. The air and combustion gases are able to exit the chamber through the outlet opening in the chamber which is remote from the tube. The confining of the flame to the vicinity of the tube also heats the upper surface of the top cap, thereby providing a hot plate on which a pot can be located to heat the contents of the pot.

Thus, according to the invention, the flame is confined within the tube and the peripheral chamber without being exposed to the outside environment. The gases which exit the peripheral chamber through the outlet opening are cooled and the introduction of air into the chamber facilitates both the cooling of the gases in the chamber before exit through the outlet opening and also tends to prevent the flame from spreading from the tube through the combustion gas outlet to the periphery of the chamber.

Thus, the likelihood of someone coming into contact with the flame is therefore prevented because the flame is completely enclosed and furthermore, since the flame is enclosed, it is unlikely to create a fire hazard should paper or other combustible material be blown across the gas burner.

In the preferred embodiment of the invention the top cap \\melbfiles\home$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 6 and peripheral chamber are formed as an integral chamber having the upper surface, a peripheral wall and a lower surface, the lower surface having a combustion tube opening into which the combustion tube projects so that the top end of the combustion tube terminates intermediate the upper surface and bottom surface, the air and combustion gas outlet being defined by the space between the top end of the combustion tube and the upper surface of the top cap, and the air inlet to the peripheral chamber being defined by a space between the periphery of the combustion tube opening in the bottom surface and the periphery of the combustion tube.

Preferably the combustion tube is coupled to the top cap by a plurality of brackets.

Preferably the burner assembly includes a bottom plate, the bottom plate being spaced from a bottom end of the combustion tube and the combustion tube being connected to the bottom plate by a plurality of brackets.

Preferably the bottom plate has an opening through which the gas burner extends to locate the gas burner and the burner head in the combustion tube.

In the preferred embodiment of the invention, the gas burner assembly includes the gas burner located within the combustion tube.

The burner assembly may also include an igniter for igniting the gas fuel to create a gas flame and flame sensing means for determining if a flame is present at the burner head.

Preferably the outlet opening in the peripheral chamber comprises a plurality of holes in the peripheral wall of the chamber.

\\melbfiles\homeS\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 7 Brief Description of the Drawings A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a view of a gas burner assembly according to the invention; and Figure 2 is a view showing the burner in use, with some components removed for ease of illustration.

Detailed Description of the Preferred Embodiment With reference to Figure 1, a gas burner assembly 10 is shown which is intended to sit in a hole 12 of a bench top, or cook top 14 of a cooking appliance. However, it should be understood that the gas burner assembly could be used in environments other than cooking appliances and, in particular, any environment in which it is desired to prevent the flame produced by the gas burner assembly from being exposed to the outside environment.

The assembly 10 includes a combustion tube 16 which is of generally cylindrical configuration, having an open top end 18 and an open bottom end 20. A bottom plate 22 supports the tube 16 by being connected to the tube 16 by a plurality of brackets 24 (such as four in number, with only two being shown in Figure 1) which have an elongate arm 25 which is attached to and extends along the inner periphery of the tube 16. The lower end of the arm 25 is provided with a finger 26 which extends at right angle to the arm 24 and the finger 26 is connected to the plate 22 by screws or other fasteners 27.

A top cap 30 is provided at the top end of the tube 16 and is supported above the tube 16 by the brackets 24. The end of the brackets 24 remote from the end 26 also have fingers 29 which extend at right angles to the arm 25 but which project in the direction opposite to the fingers 26.

\\melb~fies\home$\Luisa\Xeep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 8 The fingers 29 are secured to an upper surface 32 of the top cap 30 by screws or other fasteners 31.

The top cap 30 also includes a bottom surface 34 which is connected to the upper surface 32 by a peripheral wall 38.

In the preferred embodiment of the invention, the top cap which is comprised of the upper wall 32, the bottom wall 34 and the peripheral wall 38, is formed as an integral single unit which is mounted over the tube 16 by connecting the upper surface 32 to the brackets 25 as previously described.

In a preferred embodiment of the invention the tube 16 is of cylindrical configuration or, in other words, circular in cross-section, and the top cap 30 is in the form of a squat cylinder which is of larger diameter than the tube 16. As is also apparent from Figure 1, the bottom surface 34 is provided with a combustion tube opening 40 into which the combustion tube 16 can project to locate the top end 18 of the tube 16 between the upper surface 32 and the bottom surface 34.

As is also apparent from Figure 1, a burner 50 having a burner head 52 is located in the combustion tube 16 with the burner head 52 being below the top end 18 of the combustion tube 16 and above bottom end 49 of the combustion tube 16.

The top cap 30 defines a peripheral chamber 60 which extends about the combustion tube 16. The space between upper end 18 of the tube 16 and upper surface 32 of the top cap 30 provides a air and combustion gas outlet 62 which communicates the combustion tube 16 with the chamber Peripheral wall 38 of the top cap 30 is provided with a plurality of holes 64 which form a combustion gas outlet from the chamber \\melb-files\homeS\Luisa\Keep\SpecCointech Prov-Gas Burner Assembly.doc 4/12/02 9 The space between bottom end 20 of the tube 16 and the plate 22 forms an air inlet 66 for allowing combustion air to enter the tube 16 and rise up to the burner head 52 for combustion with gas fuel leaving the burner head 52.

An igniter 67 and a flame sensor 69 may be provided in the gas tube 16 for igniting the flame and sensing the presence of the flame, and which operate in a conventional manner, and therefore will not be described in any further detail herein.

The plate 22 is also provided with an opening 71 through which the burner 50 extends so as to locate the burner head 52 and the tube 16 as is shown in Figure 1.

Figure 2 illustrates operation of the burner assembly according to Figure 1, and in Figure 2, some of the parts have been removed for ease of illustration.

As is also apparent from Figure 1, the burner assembly can be supported in the top surface 14 by the bottom surface 34 of the cover 30 resting on the top surface 14 to locate the burner assembly in place within the cooking appliance or other device with which the burner assembly is used.

Combustion air to support combustion of gas within the tube 16 is able to enter through air inlet 66 as shown by arrows A in Figure 2. The combustion air rises up through the tube 16 to the burner head 52 where the air mixes with gas from the burner head 52 and which is ignited to create flame F. The combustion tube 16 generally confines the flame to the combustion tube 16, with the flame extending upwardly and impinging on the inner side of the upper surface 32. Combustion gas and unburnt air, as well as part of the flame F spreads out and exits the combustion tube 16 through the combustion gas outlet 62, which is in \\melb_files\home$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 10 the form of an annular opening between the top end 18 of the tube 16 and the surface 32, with the annular opening only being partly closed by the brackets 25 which extend between the tube 16 and the surface 22. The creation of the flame in the tube 16 tends to suck air in the direction of arrow A through the air inlet 66 to facilitate proper combustion of gas in the tube 16.

The air which enters the air inlet 40 into the chamber as shown by arrows B, cools the combustion products which enter the chamber 60 through the combustion outlet 62, and also act as a sheering air flow which tends to confine the flame to the region of the opening 62 without allowing the flame from the burner 52 to spread through the opening 62 into the chamber 60 to any great extent. Thus, the flame is confined to the region of the tube 16 and will not tend to spread outwardly and flash out of the burner assembly through the openings 38 which would otherwise expose flame to the outside environment.

Because of the introduction of the air in the direction of arrow B, the combustion gases within the chamber 60 are cooled and exit the outlet holes 64 in a relatively cooler state.

The flame F which is established by the gas burner 52 therefore generally has a hottest region as shown by the darker shading in Figure 2, with the lighter shading representing cooler regions of the flame and combustion gas produced by the burner head 52. As is apparent, the region of the chamber 60 adjacent to the peripheral wall 38 is cooler than the region adjacent the tube 16 to which the flame is confined. The impingement of the flame on the inner side of the upper surface 32 heats the surface 32 to provide a hot plate effect so that a pot can be located on the surface 32 to cook the contents of the pot.

\\melbfies\homeS\Luia\Kee\Seci\CointeCh Prov-Gas Burner Assembly.doc 4/12/02 11 The air flow through the opening 66 and the opening 40 and the escape of combustion gases through the outlet 62 enables the flame F to be established within the tube 16 and retained within the tube 16 without smothering and without the production of noxious combustion gases, which may be produced if incomplete combustion from the burner 52 is created. Thus, the air flow arrangement described above enables the complete combustion of the gas leaving the burner 52 in the same manner as if the burner 52 is exposed to the outside environment, thereby resulting in the burner 52 operating properly, notwithstanding the fact that the flame F is confined to the region of the combustion tube 16.

The confining of the flame F to the combustion tube 16 thereby ensures that the flame is not exposed to the outside environment, thereby eliminating the possibility that a user reaching across the burner assembly can be burnt by naked flame and also reducing the likelihood of any combustible material which is blown into the path of the burner assembly igniting because the combustible material will not come into contact with naked flame from the burner 52.

In other embodiments not shown, the peripheral wall 38 and the upper wall 32 of the top cap 30 may be formed as a single integral unit in a stamping operation. The bottom wall 34 may then be attached to the peripheral wall by mounting lugs and welding. The peripheral wall 38 may also extend downwardly beyond the bottom wall 34 rather than terminating flush with the wall 34 as shown in the drawings. The arms 25 may also be provided on the external surface of the tube 16 rather than the internal surface as shown in the drawings. Lugs may be provided no an inner peripheral part of the bottom wall 34 so as to space the wall 34 from the tube 16 to locate the tube 16 centrally in the opening \\melbfiles\home$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02 12 Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

\\melb_iles\hmefiehe$\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02

Claims (8)

1. A gas burner assembly including: a combustion tube for receiving a gas burner which has a burner head at which a flame is to be established, the combustion tube having a top end arranged above the burner head of the gas burner when the gas burner is located in the tube; an air inlet for allowing air to enter the tube, the air inlet being located below the burner head of the gas burner when the gas burner is located in the tube; a top cap having an upper surface arranged over the top end of the tube; a peripheral chamber extending about the top end of the tube; an air and combustion gas outlet located above the burner head of the gas burner when the gas burner is located in the combustion tube, for communicating the combustion tube with the chamber; an air inlet in the peripheral chamber adjacent the combustion tube; and an outlet opening in the peripheral chamber remote from the combustion tube.

2. The assembly of claim 1 wherein the top cap and peripheral chamber are formed as an integral unit comprised of at least the upper surface and the peripheral wall, the chamber also having a lower surface, the lower surface having a combustion tube opening into which the combustion tube projects so that the top end of the combustion tube terminates intermediate the upper surface and bottom surface, the air and combustion gas outlet being defined by the space between the top end of the combustion tube and the upper surface of the top cap, and the air inlet to the peripheral chamber being defined by a space between the periphery of the combustion tube opening in the bottom surface and the periphery of the combustion \\nelbbfiles\homeS\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assemblydoc 4/12/02 14 tube.

3. The assembly of claim 1 or 2 wherein the combustion tube is coupled to the top cap by a plurality of brackets.

4. The assembly of claim 1, 2 or 3 wherein the burner assembly includes a bottom plate, the bottom plate being spaced from a bottom end of the combustion tube and the combustion tube being connected to the bottom plate by a plurality of brackets.

The assembly of claim 4 wherein the bottom plate has an opening through which the gas burner extends to locate the gas burner and the burner head in the combustion tube.

6. The assembly of any one of claims 1 to 5 wherein the gas burner assembly includes the gas burner located within the combustion tube.

7. The assembly of any one of claims 1 to 6 wherein burner assembly includes an igniter for igniting the gas fuel to create a gas flame and flame sensing means for determining if a flame is present at the burner head.

8. The assembly of any one of claims 1 to 7 wherein the outlet opening in the peripheral chamber comprises a plurality of holes in the peripheral wall of the chamber. \\melb_files\homeS\Luisa\Keep\Speci\Cointech Prov-Gas Burner Assembly.doc 4/12/02