GB2302940A

GB2302940A - Gas burner rings

Info

Publication number: GB2302940A
Application number: GB9613291A
Authority: GB
Inventors: Garry Owen Thompson
Original assignee: Ausmark International Pty Ltd
Current assignee: Ausmark International Pty Ltd
Priority date: 1995-06-29
Filing date: 1996-06-25
Publication date: 1997-02-05
Anticipated expiration: 2016-06-25
Also published as: GB9613291D0; GB2302940B; AUPN387895A0

Abstract

A castellated gas burner ring (3) for a gas burner assembly has an annular ring portion (30) and a multiplicity of projections (40, 45) which extend radially inwardly from the inner cylindrical surface (31) of the ring portion (30). The projections (40, 45) have upper parts (47, 47') which extend above the upper surface (34) of the ring portion (30). Recesses (49) between the upper parts (47, 47') form gas outlet ports in a gas burner assembly when the ring (3) is mounted on a burner base (1) and a burner cap (21) is mounted on the ring (3). The burner ring (3) may be formed from a cylindrical extension (70) (Fig. 7) having longitudinally extending ridges (74, 75) which project radially inwardly from the inner surface of the extrusion, the extrusion being subsequently machined to form outer arcuate surfaces (42, 42'; 61) and flat upper and lower surfaces (43, 43', 53; 44, 44', 54) of the projections.

Description

IMPROVEMENTS IN OR RELATING TO GAS BURNER RINGS This invention relates to gas burner assemblies and is particularly, but not exclusively, concerned with a burner ring for a gas burner assembly which has a multiplicity of gas outlet ports.

Gas burner assemblies are known which have a burner ring on a burner body or base, the burner ring having a plurality of grooves in its upper surface which form gas outlet ports when a burner cap is mounted on the burner ring. Such burner rings are conventionally formed by casting the ring from iron, steel, aluminium or other metal, but the cost of casting burner rings from dies to provide a multiplicity of grooves can be expensive, and if the grooves in the cast burner ring have rough edges the quality of flame produced by the burner can be adversely affected. It is therefore desirable to provide a gas burner assembly incorporating a gas burner ring in which at least some of the disadvantages of prior art burners are alleviated.

It is also desirable to provide a gas burner assembly of a relatively simple construction which is easy to assemble.

It is desirable to provide a burner ring for a gas burner assembly which is relatively inexpensive to manufacture and which can provide a multiplicity of gas outlet ports.

It is further desirable to provide an improved method of forming a gas burner ring for a gas burner assembly.

According to a first aspect of the invention, there is provided a burner ring for a gas burner assembly, wherein said burner ring comprises a ring portion and a multiplicity of projections provided on an inner or outer surface of said ring portion, said projections having recesses therebetween for forming a multiplicity of gas outlet ports.

The ring portion is preferably of annular form having inner and outer cylindrical surfaces and, preferably, the projections are provided on, and extend inwardly from the inner cylindrical surface of the ring portion and extend above or below the annular ring portion to provide a castellated burner ring.

In a preferred construction, the projections provided on the inner surface extend above an upper surface of the ring portion and at least some of the projections may include cap mounting means for mounting a burner cap on the ring.

The cap mounting means on a projection may conveniently comprise a location portion on the projection which extends inwardly towards the centre of the burner ring and upwardly from the upper surface of the main part of the projection. The location portion preferably has an upper surface for engagement with the burner cap and an outer arcuate surface for engagement with an inner surface of a flange or rim of the burner cap.

The ring portion preferably has a lower seating surface for engagement with a burner base. At least some of the projections on the ring portion may include means for mounting or locating the burner ring on the burner base. Conveniently, the mounting or locating means may comprise an engagement portion extending below the ring portion and engageable with the burner base for mounting or locating the burner ring in position on the base.

In a particularly preferred embodiment, the cap mounting means and the mounting or locating means for mounting or locating the burner ring on the burner base are provided on common projections on the inner cylindrical surface of the annular ring portion.

According to a second aspect of the invention there is provided a gas burner assembly comprising a burner body or base having an inlet for connection to a source of gas, a burner ring adapted to be mounted to said burner body or base, and a burner cap, wherein said burner ring has a ring portion having a lower seating surface adapted to engage with a seating surface of said body or base, and a multiplicity of projections provided on an inner or outer surface of said ring portion, said projections extending above said ring portion and having recesses therebetween to form, with said cap, a multiplicity of gas outlet ports.

In a preferred construction, the burner body or base has an inner base part surrounding a central inlet opening and an outer skirt part. Preferably, the annular ring portion of the burner ring has a downwardly and inwardly inclined seating surface for engagement with a complementary seating surface on the inner base part.

The ring portion is preferably of annular form with said projections extending inwardly from a substantially cylindrical inner surface of said annular ring portion.

At least some of the inwardly extending projections on the inner cylindrical surface of the ring portion preferably extend downwardly below the annular ring portion and have outer arcuate surfaces for engagement with an inwardly facing cylindrical wall of the inner base part to assist in locating the burner ring in position on the burner base.

The burner cap is preferably in the form of a cap disc for engagement with cap mounting means of the burner ring. The cap disc preferably has a downwardly depending rim or flange and at least some of the projections of the burner ring have location portions which extend upwardly from main parts of the projections above the burner ring and which have outer surfaces engage able with the rim or flange of the cap disc to locate the cap disc in position. In a particular preferred construction, the disc cap is generally circular and has a downwardly depending annular rim or flange for engagement with arcuate outer surfaces of the projections. The cap is preferably formed of sintered iron, but may be formed from any other suitable metal or ceramics material.

The burner ring of the invention may conveniently be formed from a generally cylindrical extrusion or pressing having a multiplicity of longitudinally extending inwardly projecting ridges on its internal surface, the cylindrical extrusion or pressing being subsequently machined to form the annular ring portion so that the inwardly projecting ridges form the projections which extend above or below the annular ring portion to form the gas outlet ports.

The burner ring may be formed from brass or any other extrudable metal or ceramic material which is able to be extruded or pressed into a generally cylindrical form having the multiplicity of inwardly projecting ridges on its internal cylindrical surface.

According to a further aspect of the present invention, there is provided a method of forming a burner ring for a gas burner assembly, wherein said method comprises the steps of: extruding or pressing a metal or ceramic material to form an extrusion or pressing having a substantially cylindrical inner surface and a multiplicity of longitudinally extending ridges projecting inwardly from said cylindrical inner surface; and machining the external surface of the extrusion or pressing to form an annular ring portion having a substantially cylindrical outer surface and upper and lower inwardly extending surfaces which extend inwardly from the substantially cylindrical outer surface to the substantially cylindrical inner surface of the extrusion or pressing, whereby the inwardly projecting ridges are arranged to extend upwardly above the upper surface of the annular ring portion to form projections which have recesses therebetween for forming gas outlet ports.

Preferably, the extrusion or pressing is machined so that the lower surface of the annular portion forms a seating surface for engagement with a complimentary seating surface of a burner base.

In a preferred method in accordance with this aspect of the invention, at least some of the longitudinally extending ridges are formed with location and/or engagement surfaces for locating or engaging a burner base and/or a burner cap.

Preferably, said location and/or engagement surfaces are formed on some of the longitudinally extending ridges which extend inwardly for a greater distance than other longitudinally extending ridges provided on the cylindrical inner surface of the extrusion or pressing.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a gas burner assembly in accordance with the invention; Figure 2 is an exploded perspective view showing the components of the gas burner assembly of Figure 1; Figure 3 is a sectional view through the gas burner assembly of Figure 1; Figure 4 is a perspective view of a burner ring member of the gas burner assembly; Figure 5 is a plan view of the burner ring member of Figure 4; Figure 6 is a side view of the burner ring member; and Figure 7 is a perspective view of an extrusion used to form the burner ring member of Figure 4.

Referring to Figures 1 to 3, there is shown a gas burner assembly which comprises a burner base 1, a burner cap 2 and a castellated burner ring member 3 disposed between the base 1 and the cap 2.

The burner base 1 preferably comprises a unitary body which may conveniently be formed from any metallic material, such as aluminium. The burner base 1 has an inner base part 10, and an outer inclined skirt part 11 on either side of an intermediate ridge part having an annular upper surface 12. The inner part 10 of the base 1 has an annular disc portion 13 having a central circular opening 4 which forms an inlet port for connection to a gas supply. A substantially cylindrical inner wall portion 14 extends upwardly from the outer edge of the annular disc portion 13. An inclined seating surface 15 extends upwardly and outwardly from the upper end of the inner cylindrical wall portion 14 to the inner edge of a short, generally horizontal annular surface 16.A short, substantially cylindrical intermediate wall 17 connects the inner edge of the upper surface 12 of the intermediate ridge part to the outer edge of the annular surface 16. A substantially cylindrical outer wall portion 18 extends downwardly from the outer edge of the upper surface 12 to the inclined skirt part 11 which extends downwardly and outwardly from the lower end of the outer cylindrical wall portion 18 to a downwardly extending generally cylindrical peripheral rim 19.

The burner ring member 3 comprises an outer ring portion 30 having inner and outer cylindrical surfaces 31 and 32 respectively and a multiplicity of projections 40, 45 which extend radially inwardly from the inner cylindrical surface 31 of the annular ring portion 30. The ring portion 30 has a generally flat upper surface 33 and an inclined lower seating surface 34 which extends downwardly and inwardly from the lower end of the outer cylindrical surface 32. The projections 40 each have inner and outer arcuate surfaces 41 and 42 respectively, generally flat upper and lower surfaces 43 and 44 and side surfaces 46.

In the preferred embodiment illustrated in the drawings, the burner ring 3 has a total of twenty-four projections 40, 45 provided on the inner surface 31 of the annular ring portion 30. Referring more specifically to Figures 4 and 5, there are four projections 45 at equally spaced, ninety degree intervals around the ring 3, with a row of five projections 40 on each side of each projection 45. In another preferred embodiment for a larger gas burner assembly, thirty-six projections may be provided, although it will be appreciated that the number of projections may vary for different sizes of burner rings and for different applications. As illustrated by Figures 4 and 5, although the surfaces 41 and 42 are arcuate, since there are a large number of projections around the burner ring, each projection 40 is approximately trapezoidal in plan view.

As shown in Figures 4 and 6, the height of each projection 40, 45 is greater than that of the annular ring portion 30 so that an upper part 47, 47' of each projection 40 extends above the upper surface 34 of the outer ring portion 30 to provide a multiplicity of recesses 49 between the side walls 46, 46' of the upper parts 47, 47' of the projections 40, 45.

The projections 45 also have inner and outer arcuate surfaces 41', 42' and side surfaces 46'. The projections 45 differ from the projections 40 in that they extend inwardly for a greater distance from the cylindrical inner surface 31 of the annular ring portion 30, and also in that their upper and lower surfaces are of stepped form.

The projections can thus be regarded as having main parts 40' with flat generally trapezoidal shaped upper and lower surfaces 43', 44' and location portions 50 which extend radially inwardly from the generally trapezoidal shaped main parts 40' of the projections 45. Each location portion 50 has generally flat upper and lower surfaces 53 and 54 respectively. The height of the location portions 50 is greater than that of the main parts 40' of the projections 45 so that each location portion 50 has upper and lower parts 51 and 52 which extend above and below the projections 40 and the main parts 40' of the projections 45. The upper surface 53 of each location portion is therefore above the upper surface 43 of each projection 40 and above a flat upper surface 43' of the main part 40' of each projection 45'.The lower surface 54 of each location portion 50 is below the lower surface 44 of each projection 40. The upper and lower parts 51 and 52 of each location portion 50 have outer arcuate engagement surfaces 61 and 62 respectively, the purpose of which will become apparent from the subsequent description.

The burner cap 2 comprises a slightly domed cap disc 21 which is substantially circular in plan view. A downwardly extending annular flange 22 is provided on the concave lower surface 23 of the cap disc 21 slightly inwardly of the peripheral edge 24 of the cap disc. The annular flange 22 has a lower surface 25 of the annular flange 22 for engagement with the upper surfaces 43 of the projections 40 and with upper surfaces 43' of the main parts 40' of the projections 45. The annular flange 22 also has an inner cylindrical surface 26 for engagement with the outer arcuate surfaces 61 of the location portions 50 on the projections 45.

In assembly of the gas burner, the burner ring 3 is mounted on the burner base 1 in such a manner that the inclined lower seating surface 34 of the annular ring portion 30 engages with the inclined seating surface 15 of the burner base. The burner ring 3 is located in position against lateral or substantially horizontal movement relative to the base 1 by the lower parts 52 of the location portions 50 of the projections 45, the outer arcuate surfaces 62 of the lower parts 52 being engageable with the substantially cylindrical inner wall portion 14 of the base to prevent or restrict such lateral movement.

After the burner ring 3 has been mounted on the burner base 1, the burner cap 2 is mounted on the burner ring 3 in such a manner that the lower surface 25 of its annular flange 22 engages with the upper surfaces 43 and 43' of the projections 40, 45, and the cap 2 is located in position by engagement of the inner cylindrical surface 26 of the annular flange 22 with the outer arcuate surfaces 61 of the location portions 50 of the projections 45. In the completed assembly illustrated in Figures 1 and 3 a gas chamber 5 is formed inside the burner ring 3 above the base 1 and below the concave lower surface 23 of the cap 2. A multiplicity of gas outlet ports 6 from the gas chamber 5 are formed by the recesses 49 between the side walls 46, 46' of the upper parts 47, 47' of the projections 40, 45; the open upper ends of the recesses 49 being closed by the lower surfaces 25 of the annular flange 22 of the cap 2.

A preferred method of forming the burner ring 3 will now be described with particular reference to Figures 4 to 7 of the drawings. First, a substantially cylindrical extrusion 70 as illustrated in Figure 7 is produced from brass or other extrudable material. The extrusion 70 has substantially cylindrical inner and outer surfaces 71 and 72 respectively and a plurality of longitudinally extending ridges 74, 75 which project inwardly from the inner cylindrical surface 71 towards the centre of the substantially cylindrical extrusion 70. The ridges 75 correspond to the inwardly extending projections 45 of the finished burner ring 3 and extend inwardly towards the centre of the extrusion for a greater distance than the ridges 74 which correspond to the projections 40 of the finished burner ring 3.

After the extrusion 70 has been formed, it is then placed on a lathe or other machining tool for machining the surfaces 32, 33 and 34 of the outer ring portion 30. When the upper and lower surfaces 33 and 34 of the ring portion 30 have been machined, the inwardly projecting ridges 74 and 75 are machined to form the outer arcuate surfaces 42, 42' and the flat upper surfaces 43, 43' of the projections 40, 45.

Then the inwardly projecting ridges 75 are machined to form the arcuate surfaces 61 and the upper surfaces 53 of the upper parts 51 of the location portions 50. The inwardly projecting ridges 74, 75 below the annular ring portion 30 are machined in a similar manner to form the flat lower surfaces 44, 44' of the projections 40 and the arcuate surfaces 61 and flat lower surfaces 54 of the lower parts 52 of the location portions 50 of the projections 45.

The method of forming the burner ring 2 in accordance with the invention is relatively easy and economical to perform requiring an extrusion step (or alternatively, a pressing step) to produce a generally cylindrical piece of metal or ceramics material with inwardly projecting longitudinally extending ridges as shown in Figure 7, and subsequent, relatively simple, machining operations to produce the castellated burner ring 2. It will be appreciated that to produce the burner ring 2 of Figure 4 by a casting method would involve the use of a die or dies of complicated form which would be relatively expensive to produce and which could have rough edges adversely affecting the quality of the burner flame or the seating of the burner ring on the burner base.

The burner assembly described above in accordance with the invention is primarily intended for use in a hot plate of a gas cooker although it may be used in other applications where a multiplicity of gas outlets are required in a burner.

It will be appreciated that various modifications and alterations may be made to the embodiment described above without departing from the scope or spirit of the present invention. For instance, the number of projections 45' which have location portions 50 for the cap 2 and/or the base 1 may vary, although it is desirable that at least three such projections should be provided at spaced intervals around the ring.

Also, a burner ring having projections on an outer cylindrical surface of an annular ring portion may be provided with the projections extending above or below the annular ring portion and having recesses between the projections for forming, with a burner base or cap, gas outlet ports. Such a burner ring may be used in conjunction with a burner ring as described in the preferred embodiment of the invention to provide inner and outer burner rings for a twin burner or "wok burner".

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A burner ring for a gas burner assembly, wherein said burner ring comprises a ring portion and a multiplicity of projections provided on an inner or outer surface of said ring portion, said projections having recesses therebetween for forming a multiplicity of gas outlet ports.

2. A burner ring according to claim 1 wherein said ring portion is of annular form having inner and outer cylindrical surfaces.

3. A burner ring according to claim 1 or claim 2 wherein the projections are provided on and extend inwardly from the inner surface of the ring portion.

4. A burner ring according to any one of claims 1 to 3 wherein the projections extend above the ring portion.

5. A burner ring according to any one of claims 1 to 4 wherein the projections extend below the ring portion.

6. A burner ring according to claim 4 wherein at least some of the projections extending above the ring portion include cap mounting means for mounting a burner cap on the ring.

7. A burner ring according io claim 6 wherein the cap mounting means on a projection comprises a location portion which extends inwardly towards the centre of the burner ring and upwardly from an upper surface of a main part of the projection.

8. A burner ring according to claim 7 wherein the location portion of a projection has an upper surface for engagement with the burner cap and an outer arcuate surface for engagement with an inner cylindrical surface of a flange or rim of the burner cap.

9. A burner ring according to any one of the preceding claims wherein the ring portion has a lower seating surface for engagement with a burner base.

10. A burner ring according to any one of the preceding claims wherein at least some of the projections include mounting or locating means for mounting or locating the burner ring on a burner base.

11. A burner ring according to claim 10 wherein the mounting or locating means of a projection comprises an engagement portion extending below the ring portion and engageable with a burner base.

12. A burner ring according to claim 10 or claim 11 as appended to any one of claims 6 to 8 wherein the cap mounting means and the mounting or locating means are provided on common projections.

13 A burner ring according to any one of the preceding claims formed from a generally cylindrical extrusion or pressing having a multiplicity of longitudinally extending inwardly projecting ridges on its inner surface, the extrusion or pressing being machined to form an annular ring portion whereby the inwardly projecting ridges form projections which extend above or below the annular ring portion.

14. A gas burner assembly comprising a burner body or base having an inlet for connection to a source of gas, a burner ring in accordance with any one of the preceding claims mounted on said burner body or base, and a burner cap mounted on said burner ring.

15. A gas burner assembly comprising a burner base having an inlet for connection to a source of gas, a burner ring adapted to be mounted to said bumer base, and a burner cap, wherein said burner ring has a ring portion having a lower seating surface adapted to engage with a seating surface of said base, and a multiplicity of projections provided on an inner or outer surface of said ring portion, said projections extending above said ring portion and having recesses therebetween to form, with said cap, a multiplicity of gas outlet ports.

16. A gas burner assembly according to claim 15 wherein the ring portion is of annular form and said projections are provided on a substantially cylindrical inner surface of the annular ring portion.

17. A gas burner assembly according to claim 15 or claim 16 wherein the burner base has an inner base part surrounding a central inlet opening and an outer skirt part and the ring portion of the burner ring has a downwardly and inwardly inclined seating surface for engagement with a complementary seating surface on the inner base part.

18. A gas burner assembly according to claim 17 as appended to claim 16 wherein at least some of the inwardly extending projections on the inner cylindrical surface of the ring portion extend downwardly below the annular ring portion and have outer arcuate surfaces for engagement with an inwardly facing cylindrical wall of the inner base part to assist in locating the burner ring in position on the burner base.

19. A gas burner assembly according to any one of claims 15 to 18 wherein the burner cap comprises a cap disc for engagement with cap mounting means of the burner ring.

20. A gas burner assembly according to claim 19 wherein the cap disc has a downwardly depending rim or flange and at least some of the projections of the burner ring have a main part extending above the ring portion and location portions which extend upwardly from the main part of the projections and which have outer surfaces engageable with the rim or flange of the cap disc to locate the cap disc in position.

21. A gas burner assembly according to claim 19 or claim 20 wherein the cap disc is generally circular having a downwardly depending annular rim for engagement with arcuate outer surfaces of the projections.

22. A method of forming a burner ring for a gas burner assembly, wherein said method comprises the steps of: extruding or pressing a metal or ceramic material to form an extrusion or pressing having a substantially cylindrical inner surface and a multiplicity of longitudinally extending ridges projecting inwardly from said cylindrical inner surface; and machining the external surface of the extrusion or pressing to form an annular ring portion having a substantially cylindrical outer surface and upper and lower inwardly extending surfaces which extend inwardly from the substantially cylindrical outer surface to the substantially cylindrical inner surface of the extrusion or pressing, whereby the inwardly projecting ridges are arranged to extend upwardly above the upper surface of the annular ring portion to form projections which have recesses therebetween for forming gas outlet ports.

23. A method of forming a burner ring according to claim 22 wherein the extrusion or pressing is machined so that the lower surface of the annular portion forms a seating surface for engagement with a complimentary seating surface of a burner base.

24. A method of forming a burner ring according to claim 22 or claim 23 wherein at least some of the longitudinally extending ridges are machined with location and/or engagement surfaces for locating or engaging a burner base and/or a burner cap.

25. A method of forming a bumer ring according to claim 24 wherein said location and/or engagement surfaces are formed on some of the longitudinally extending ridges which extend inwardly for a greater distance than other longitudinally extending ridges provided on the cylindrical inner surface of the extrusion or pressing.

26. A gas burner assembly substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.

27. A burner ring substantially as hereinbefore described with reference to Figures 4 to 6 of the accompanying drawings.

28. A method of forming a burner ring substantially as hereinbefore described with reference to Figures 4 to 7 of the accompanying drawings.