Gas burner

Abstract

 A gas burner 40 comprising a cylindrical flame strip 42 with a distributor located therein. A mounting flange 46 is provided at one end of the burner 40, with the flange 46 having a mechanical mounting to both the flame strip 42 and the distributor.

Description

[0001] This invention relates to a gas burner, and particularly but not exclusively to a gas burner for use in domestic heating appliances.

[0002] The burner may be of the "premix" type, meaning that all the air required for combustion is mixed with a fuel gas prior to burning.

[0003] This invention relates to burners of the type which include a cavity for receiving a gas and air mixture, a cylindrical distributor surrounding the cavity with relatively large through holes therein. A cylindrical flame strip surrounds the distributor, with a plurality of relatively small through holes therein defining flame ports through which the gas and air mixture may pass immediately prior to combustion.

[0004] In some instances it is required to provide a restrictor tube which is a tube of a smaller diameter which extends coaxially within the distributor for part of the length thereof. Restrictor tubes can help to alleviate noise in gas burners.

[0005] According to one aspect of the present invention there is provided a gas burner, the gas burner including an internal cavity for receiving a gas and air mixture, a distributor in the form of a cylindrical wall surrounding the cavity with a plurality of through holes in the wall, a flame strip in the form of a cylindrical wall coaxially surrounding the distributor, with a plurality of through holes in the wall of the flame strip, and an external mounting flange provided at one end of the cavity, the external mounting flange having a mechanical mounting to both the distributor and flame strip at said one end.

[0006] End parts of the distributor and flame stripe at said one end may be turned relative to the remainder of the distributor and flame strip.

[0007] The external mounting flange may be mounted to the end parts of the distributor and flame strip. Respective end parts of the distributor and flame strip may overlap with each other at said one end.

[0008] Aligned openings may be provided in the overlapping end parts of the distributor and flame strip, and the external mounting flange may include a plurality of projections each extendable through respective aligned openings to mount the external mounting flange to the distributor and flame strip.

[0009] The projections may be profiled such that they cannot be pulled directly out of the aligned openings in the distributor and flame strip, thereby retaining the external mounting flange, distributor and flame strip together.

[0010] The projections may extend through only some of the aligned openings in the distributor and flame strip, with others of the aligned openings left open.

[0011] The end part of the flame strip may be turned inwardly, whilst the end part of the distributor may be turned outwardly, such that one of the end parts may overlap the other.

[0012] The end parts may be in the form of curved lips, which may nest together.

[0013] The burner may also include an end cap at the other end thereof, which end cap closes the flame strip and distributor. The end cap may be mounted on the other end of the flame strip by folding part of the end cap over the end of the flame strip.

[0014] The distributor and/or flame strip may be formed from shaped sheet metal, and a mechanical join may be provided between ends of the sheet material to form the cylindrical shape.

[0015] The invention further provides a method of forming a gas burner according to any of the preceding ten paragraphs, the method including aligning openings in the distributor and flame strip, locating projections on the external mounting flange to extend through the aligned openings, and deforming ends of the projections such that they cannot pass back out of the aligned openings.

[0016] The projection ends may be deformed by locating a tool between the distributor and flame strip from the other end thereof, and deforming the projection ends with the tool.

[0017] The projection ends may be deformed before the end cap is mounted on the other end of the flame strip.

[0018] An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which :-

Fig. 1 is a diagrammatic perspective view of a conventional burner in place within an appliance;

Fig. 2 is a perspective view from above of a burner according to the invention;

Fig. 3 is a diagrammatic side view of the burner of fig. 2;

Fig. 4 is a cross sectional view along the line A - A of fig. 3;

Fig. 5 is a detailed view of part of fig. 4;

Fig. 6 is a perspective view from beneath of the burner of fig. 2;

Fig. 7 is a detailed part of fig. 6; and

Fig. 8 is a detailed perspective view of a part of the burner of fig. 2 from beneath.

[0019] Fig. 1 shows by way of illustration a gas burner 10 located within a heating appliance including a combustion zone 12 and heat exchanger 14. The gas burner 10 includes a cylindrical flame strip 16 with a concentric inner distributor 18, enclosing an internal cavity 20. An end cap 22 is attached to the flame strip 16 and closes one axial end of the gas burner 10. A mounting flange 24 is attached to the other axial end of the flame strip 16 and extends radially outwardly therefrom. The gas burner 10 is attached to a housing 26 via the mounting flange 24.

[0020] The flame strip is provided with through holes in the form of flame ports 32, just a few of which are shown in Fig. 1. The flame ports are about 1 mm in diameter, and their centres are about 2 - 3mm apart. The flame ports 32 are arranged evenly over the flame strip 16. The distributor 18 is provided with a regular pattern of larger through holes 28.

[0021] In use, a gas and air mixture is passed into the cavity 20 and passes through the holes 28 in the distributor 20, and out through the flame ports 32 and into the combustion zone 12 where burning takes place. The heat thereby produced is utilised via the heat exchanger 14, with the flue products passing out of the unit as indicated by the arrow A.

[0022] Figs. 2 to 8 show a first gas burner 40 according to the invention. The burner 40 comprises a flame strip 42, with a distributor 44 located therein. A mounting flange 46 is provided at one end of the burner 40, with an end cap 48 at the opposite end.

[0023] The flame strip 42 comprises a cylindrical wall 50 with a plurality of openings 52 therethrough some of which are shown in the drawings. At the one end the wall 50 is turned inwardly to define a flange 54. A plurality of circumferential slots 56 are provided at the join between the cylindrical wall 50 and the flange 52. The wall 50 at the other end of the flame strip 42 is turned outwardly and back upon itself to define a lip 70. The circumferential slots 56 facilitate bending of the flange 52 to provide the outer part 54 parallel thereto.

[0024] The distributor 44 is again of cylindrical form with through holes 58 formed in a cylindrical wall 60. The distributor 44 may be formed in a similar fashion to the flame strip 42 from a sheet of metal, with a mechanical fastening 62 to retain the distributor 44 in a cylindrical configuration. At the one end the wall 60 of the distributor is curved outwardly to define a flange 64. A plurality of circumferential slots 66 are provided at the join between the wall 60 and flange 64.

[0025] The end cap 48 comprises a shaped piece with an inner portion 68 which locates within the distributor 44, to retain same in a required position. The outer edge of the end cap 48 provides a rim 72 which can be formed to overlap the lip 70 at the opposite end of the flame strip 42.

[0026] The flange of the flame strip 42 locates on the flange 66 of the distributor 44, with the respective slots 56, 66 aligned with each other.

[0027] The mounting flange 46 comprises a flange part 74 with a plurality of spaced projections 76 on the inner edge thereof, which projections 76 are upstanding towards the flame strip 42 and distributor 44. The projections 76 locate in every other pair of aligned slots 56, 66, and the distal end of the projections 76 is bent over to retain the projections 76 extending through the aligned openings 56, 66.

[0028] In forming the burner 40, the projections 76 are located extending through the aligned openings 56, 66 before the end cap 48 is fitted onto the flame strip 42 and distributor 44. A tool can then be inserted between the flame strip 42 and distributor 44 to deform the end of the projections 76 to retain the flange 46 mounted on the flame strip 42 and distributor 44.

[0029] In use the aligned openings, and particularly those without projections extending therethrough, act as a bypass for combustion gas between the flame strip and distributor. This tends to cut down noise during burning, and helps to prevent resonance which can occur.

[0030] There is therefore provided a gas burner which can be formed purely by mechanical steps and does not require any welding or other joining techniques. The mounting flange can readily be mounted on the flame strip and distributor. As this is a separate component, it means for instance that the mounting flange can be made of a different material, and particularly of a different thickness of material to the flame strip and distributor.

[0031] It is to be realised that various modifications may be made without departing from the scope of the invention. For instance the mounting flange could be differently mounted to the flame strip and distributor. The flame strip and/or distributor could be differently formed. The end cap may be differently mounted to the flame strip and/or distributor.

[0032] Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A gas burner, the gas burner including an internal cavity for receiving a gas and air mixture, a distributor in the form of a cylindrical wall surrounding the cavity with a plurality of through holes in the wall, a flame strip in the form of a cylindrical wall coaxially surrounding the distributor, with a plurality of through holes in the wall of the flame strip, and an external mounting flange provided at one end of the cavity, the external mounting flange having a mechanical mounting to both the distributor and flame strip at said one end.

2. A gas burner according to claim 1, characterised in that end parts of the distributor and flame stripe at said one end are turned relative to the remainder of the distributor and flame strip.

3. A gas burner according to claim 2, characterised in that the external mounting flange is mounted to the end parts of the distributor and flame strip.

4. A gas burner according to claims 2 or 3, characterised in that respective end parts of the distributor and flame strip overlap with each other at said one end.

5. A gas burner according to claim 4, characterised in that aligned openings are provided in the overlapping end parts of the distributor and flame strip.

6. A gas burner according to claim 5, characterised in that the external mounting flange includes a plurality of projections each extendable through respective aligned openings to mount the external mounting flange to the distributor and flame strip.

7. A gas burner according to claim 6, characterised in that the projections are profiled such that they cannot be pulled directly out of the aligned openings in the distributor and flame strip, thereby retaining the external mounting flange, distributor and flame strip together.

8. A gas burner according to claims 6 or 7, characterised in that the projections extend through only some of the aligned openings in the distributor and flame strip, with others of the aligned openings left open.

9. A gas burner according to any of claims 2 to 8, characterised in that the end part of the flame strip is turned inwardly, whilst the end part of the distributor is turned outwardly, such that one of the end parts overlaps the other.

10. A gas burner according to claim 9, characterised in that the end parts are in the form of curved lips, which may nest together.

11. A gas burner according to any of the preceding claims, characterised in that the burner also includes an end cap at the other end thereof, which end cap closes the flame strip and distributor, and the end cap may be mounted on the other end of the flame strip by folding part of the end cap over the end of the flame strip.

12. A gas burner according to any of the preceding claims, characterised in that the distributor and/or flame strip are formed from shaped sheet metal, and a mechanical join may be provided between ends of the sheet material to form the cylindrical shape.

13. A method of forming a gas burner according to any of the preceding claims, the method including aligning openings in the distributor and flame strip, locating projections on the external mounting flange to extend through the aligned openings, and deforming ends of the projections such that they cannot pass back out of the aligned openings.

14. A method according to claim 13, characterised in that the projection ends are deformed by locating a tool between the distributor and flame strip from the other end thereof, and deforming the projection ends with the tool.

15. A method according to claims 13 or 14, characterised in that the projection ends are deformed before the end cap is mounted on the other end of the flame strip.

Drawing