GB2117508A

GB2117508A - Gas burner heads

Info

Publication number: GB2117508A
Application number: GB08301041A
Authority: GB
Inventors: Arthur Selwyn Kay
Original assignee: Burco Dean Ltd
Current assignee: Burco Dean Ltd
Priority date: 1982-01-16
Filing date: 1983-01-14
Publication date: 1983-10-12
Also published as: GB2117508B; GB8301041D0

Abstract

A gas burner head comprising an upper member 5 defining a series of apertures 18 through which a gas/air mixture may pass from the interior of the burner head to the exterior thereof to be burnt off. The apertures are arranged in pairs such that the gas/air mixture flows from one of the apertures of a pair so as to impinge directly on the gas/air mixture flowing from the other aperture of the pair, whereby the gas/air mixture flowing from each pair of apertures is thoroughly mixed to produce a stable flame when burnt. <IMAGE>

Description

SPECIFICATION Gas burner heads The present invention relates to gas burner heads and in particular to gas burner heads adapted to burn natural gas.

Conventionally, natural gas burner heads receive a gas/air mixture and are provided with one series of apertures, which form the main outlet ports for the gas/air mixture, and a second series of apertures, which form retention ports through which the gas/air mixture flows to stabilise the flames. In some burners, the second series of apertures is replaced by a narrow slit. In the conventional gas burners it is necessary to provide a venturi in the inlet to the burner to ensure that the gas/air mixture supplied to the burner is adequately mixed.

The object of the pesent invention is to provide a gas burner head and in particular a natural gas burner head in which the need for a venturi and retention ports is obviated.

According to the present invention there is provided a gas burner head comprising an upper member defining a series of apertures through which a gas/air mixture may pass from the interior of the burner head to the exterior thereof to be burnt off, wherein the apertures are arranged in pairs such thatthe gas/air mixture flows from one of the apertures of a pair so as to impinge directly on the gas/air mixture flowing from the other aperture of the pair, whereby the gas/air mixture flowing from each pair of apertures is thoroughly mixed to produce a stable flame when burnt.

Preferably, the apertures of each pair are arranged directly opposing one another.

The cap may comprise a central member defining an upper surface and a peripheral rim which extends downwards from the upper surface, the apertures being formed in the rim or in the rim and the periphery of the upper surface. The rim may be integral with or separable from the central member.

A series of pairs of adjacent slits may be provided in the cap portions of the cap between each pair of slits extending inwardly or outwardly of the cap to define a pair of apertures at the sides of the said portion. The slits may extend to the edge of the rim.

Alternatively, the rim may be corrugated, the corrugations extending perpendicular to the edge of the rim and apertures being provided in each side of some or all of the corrugations.

A spark ignition tip may be arranged adjacent a gas outlet opening in the head, the edge of the opening projecting from the head towards the spark tip such that sparks are caused to travel between the spark tip and the edge of the opening.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a verticai section through a gas burner embodying the present invention; Figure 2 is a perspective view from above and to one side of the gas burner of Figure 1; Figure 3 is a partial perspective view from below and to one side of a bowl which is part of the gas burner of Figures 1 and 2; Figure 4 is a side view of another gas burner according to the present invention manufactured from sheet steel; Figure 5 is a sectional view on the line V-V of Figure 4; Figure 6 is a sectional view of another gas burner according to the present invention; Figure 7 is a perspective view of a flame strip which forms part of the gas burner of Figure 6;; Figure 8 is a perspective view of an alternative flame strip to that shown in Figure 7; and Figure 9 is a perspective view of another embodi mentofa cap for use in a gas burner similar to that shown in Figure 1.

Referring to Figures 1 and 2, the illustrated gas burner comprises a burner head comprising a bowl-shaped upper body section 1, a tubular intermediate body section 2, and a lower body section 3 communicating with a gas inlet pipe 4. The head supports a cap 5 which is secured in position by a bolt 6 extending through the base of the head into engagement with a nut 7.

As shown in Figure 2, an electronic ignition spark plug is support by the burner head. The plug comprises a metallic tip 8 to which an electrical connection can be made view terminal 9, a ceramic tube 10 insulating the tip 9 from a mounting plate 11, and a support 12 which is secured to the underside of the bowl section 1 and which supports the plate 11.

As may be seen from Figure 2 and 3, the plug tip 8 is located within a part-circular recess 13 defined in the side of the bowl-shaped body section 1. The upper side of the recess 13 is defined by a flat surface 14 in which two holes 15 and 16 are formed, the hole 16 being defined by an axial passageway through a rivet 17 secured in an aperture in the surface 14.

The cap 5 is seated around the rim of the bowl-shaped body section 1 and is formed with a series of apertures 18 through which gas may flow to the exterior of the burner head to be burnt off.

The cap 5 comprises a circular central member with a convex upper surface 19 and an annular peripheral rim 20 extending downwards from the surface 19. Around the periphery of the upper surface 19 where it adjoins the rim 20, the cap is pierced by a series of pairs of adjacent slits, portions of the cap between each pair of slits being bent inwards such that the series of apertures 18 are formed between alternate outwardly curving and inwardly curving formations 21 and 22 respectively.

As can be most easily appreciated from a consideration of Figure 2, when an air/gas mixture is supplied via the pipe 4 it issues into the spaces between adjacent outwardly curved portions 21 in two jets which collide. This causes considerable turbulence and ensures that the air/gas mixture is mixed sufficiently thoroughly to provide a good burning characteristic, even if the air/gas mixture supplied via pipe 4 is only partially mixed. (Some mixing does occur in the pipe 4 and the lower body section 3). This means that it is not necessary to provide a Venturi in the pipe 4 as in conventional burner heads. This is particularly useful as a conventional burner head having a Venturi must be accurately aligned with the gas jet to ensure that the Venturi functions properly. It also reduces the minimum length of the pipe 4.

To ignite gas issuing from the apertures 18 a potential is applied to the terminal 9 (Figure 2) causing a spark to jump between the tip 8 and the nearest earthed metallic surface which is rivet 17, the rivet projecting from the head towards the spark tip.

This ignites gas issuing from the hole 16 in the rivet 17, thereby igniting gas issuing from the hole 15 and apertures 18 in turn.

The rivet 17 is provided to ensure that the ignition spark travels as close as possible to the gas hole 16.

The same effect could be obtained by raising the edge of the hole 16 relative to the surface 14 in any other way. For example, the hole 16 could be integrally cast with a projecting edge, or it could be punched or pressed out from the side which will be adjacent the cap 5 so that the lower edge of the hole 16 is forced downwards.

The drawings shown the burner head arrangement as a casting. It will be appreciated that the burner head and the inlet tube and primary air casing (which replaces the normal venturi) may be made by various methods and in a variety of materials, for example cast iron, aluminium, or sheet metal.

The apertures 18 may be equally spaced apart around the cap 5 as shown or may be arranged in for example four or five groups, the spaces between the groups defining regions of reduced gas flow. The groups may be arranged to provide reduced gas flow regions around a pan support reduced gas flow regions around a pan support (not shown) or the like located above the burner head.

Referring now to Figure 4 and 5, a gas burner head similar to that of Figures 1 to 3 is illustrated.

Equivalent components are identified by the same reference numerals in Figures 1 to 3 and Figure 4 and 5.

It will be noted that the embodiment of Figures 4 and 5 is manufactured from sheet steel, the cap 5 being a push fit onto the burner head body. The burner head body is provided with a shoulder 23 which rests in use against an upstanding rim 24 (shown in dotted linges) of a cooker hob top. The hole 16 is simply punched out from above so that its edges project downwards towards the tip 8. The inlet pipe 4 is fixed to the burner head body by a simple collapse flange joint.

Figure 6 shows a further embodiment of the invention which is also similar to the embodiment of Figures 1 and 3 and in which the same reference numerals are used where applicable. The cap 5 does however differ significantly from the cap of Figures 1 to 5, as in Figure 6 the cap has separable rim whereas in Figures 1 to 5 the rim is integral with the central member of the cap.

The cap 5 of Figure 6 is held in position by bolt 6 but is separated from the body 1 by a rim in the form of a flame strip 25 which is retained inwardly by a flange 26. The strip 25 is shown in detail in Figure 7 and it will be seen that it is formed from a corrugated strip with apertures 27 being formed through it. The apertures 27 ailow gas to pass from the interior to the exterior of the burner head to be burnt off. Flaps (now shown) may be punched out from the flame strip 26 at, for example, three equiangularly spaced positions around the corrugated strip whereby the strip is located in position around the rim of the body 1.

In a modification (not shown), the periphery of the central member of the cap 5 is flared concially upwards and the upper surface of the flame strip 26 is similarly complementarily frusto-conically shaped. This arrangement throws the flames of the burner upward towards a pot or pan placed on the burner. A further advantage is that the central member of the cap 5 can be positively located on the flame strip 26 during the assembly of the burner head.

The construction of the flame strip 26 of Figures 6 and 7 will now be described in detail. The strip 26 is corrugated with corrugations which are intended to be aligned parallel to the longitudinal axis of the assembled burner head. The apertures 27 are formed in each of the side walls defining each trough of the corrugations. Thus, in each trough there is a pair of directly opposing apertures 27.

In a modification, a plurality of annular rings of apertures 27 may be formed but as before pairs of opposing apertures 27 must be formed.

Figure 8 shows a second embodiment of flame strip 28 which could be used in the burner of Figure 6 in place of that described with reference to Figure 7.

In this case, the strip 28 is formed with a series of spaced outstanding formations 29 located between respective pairs of slits. At two opposed edges 30 of each formation 29 apertures are formed each of which apertures is defined by the edge 30 of the formation 29 and the immediately adjacent portion of the strip 28. It can thus be seen that a series of pairs of directly opposing apertures is formed around the strip 28 between adjacent formations 29.

The strip 28 may be modified by the formation of complementary indented formations similar in shape to the formations 29 but positioned between them and extending inwards rather than outwards.

The provision of these indented formations increases the cross-sectional area of the apertures.

Apart from the use of the flame strips 26, 28 in the burner as described these strips could by used in any appropriate burner and may be used in a linear condition in a burner with a linearly shaped aperture as opposed to an annularly shaped aperture. Such a burner is usually termed a strip burner.

It will also be appreciated that many different forms of flame strips may be used in the gas burner as shown in Figure 6 provided the flame strips are apertured and configured such that in use a gas flow passing through one aperture impinges directly on a gas flow passing through another aperture.

A modified cap 5 is shown in Figure 9 which is designed to clip or be a push-fit onto a gas burner head such as that shown in Figure 1. The rim of the cap 5 depends from the upper surface of the cap 5 and is cut to form a series of slits between which an alternating series of pairs of flaps or tongues 31 and 32 are defined, the slits extending to the edge of the cap rim. The tongues 31 and 32 are inclined at different angles to the upper surface of the cap 5 so that between immediately adjacent edges of each pair of tongues 31 and 32 respectively there is a gap which forms an aperture 33 in the assembled burner.

These apertures 33 form a series of pairs of directly opposing apertures around the periphery of the cap 5. It will be appreciated that the tongues 32 additionally form the means whereby the cap 5 may be push-fitted onto a rim of a burner head body.

When any of the abovementioned embodiments of burner are in use, gas passes through the apertures formed in the flame strip or the cap to the exterior of the burner to be burnt off. The gas flows from each pair of directly opposing apertures impinge directly on each other and as a result fan outwards and upwards. The flame produced by this combined upwardly flowing gas flow is itselffan- shaped and is automatically directed upwards towards that which is to be heated by the burner. Thus a ring of flame is formed around the burner. Further, the flames of the burner are stable. As each flame emanates from acombinedgasflowformed bytwo separate directly impinging flows, each of these impinging flows stabilises and forms a retention gas flow for the other and thus gives rise to a stable flame. The stabilizing effect of one of the gas flows on the other is particularly important when natural gas is used.

Other advantages of the burners as described above are that because the gas flow from each aperture is constrained to fan outwards, the temperature of the environment around the apertured region ofthe burner head remains at a low level in comparison with the flame temperature and may, in fact be kept low enough for the bowl of the burner to be made of an aluminium die casting, which is cheaper than stainless steel, which is normally used for making gas burners. Further, the flames do not impinge directly on the metal cap of the burner and are not thereby cooled. Thus, the cap can also be made of an aluminised mild steel and the gas is burnt more efficiency with a more intense flame.

Claims

1. A gas burner head comprising an upper member defining a series of apertures through which a gas/air mixture may pass from the interior of the burner head to the exterior thereof to be burnt off, wherein the apertures are arranged in pairs such that the gas/air mixture flows from one of the apertures of a pair so as to impinge directly on the gas/air mixture flowing from the other apertures of the pair, whereby the gas/air mixture flowing from each pair of apertures is thoroughly mixed to produce a stable flame when burnt.

2. A gas burner head according to claim 1, wherein the apertures of each pair are arranged directly opposing one another.

3. A gas burner head according to claim 1 or 2, wherein the cap comprises a central member defining an upper surface and a peripheral rim which extends downwards from the upper surface, the apertures being formed in the rim or in the rim and the periphery of the upper surface.

4. A gas burner head according to claim 3, wherein the rim is integral with the central member.

5. A gas burner head according to claim 3, wherein the rim comprises a strip separable from the central member.

6. A gas burner head according to claim 3,4 or 5, wherein a series of pairs of adjacent slits are provided in the cap, portions of the cap between each pair of slits extending inwardly or outwardly of the cap to define a pair of apertures at the sides of the said portion.

7. A gas burner head according to claim 6, wherein the slits extend to the edge of the rim.

8. A gas burner head according to claim 3,4 or 5, wherein the rim is corrugated, the corrugations extending perpendicular to the edge of the rim and apertures being provided in each side of some or all of the corrugations.

9. A gas burner head according to any preceding claim, comprising a spark ignition tip arranged adjacent a gas outlet opening in the head, the edge of the opening projecting from the head towards the spark tip such that sparks are caused to travel between the spark tip and the edge of the opening.

10. A gas burner head according to claim 9, wherein the opening is formed in a rivet positioned within a hole in the head.

11. A gas burner head according to claim 9, wherein the opening is punched or pressed from sheet material such that its edges are deformed towards the spark tip.

12. A gas burner head comprising a spark ignition tip arranged adjacent a gas outlet opening in the head, the edge of the opening projecting from the head towards the spark tip such that sparks are cuased to travel between the spark tip and the edge of the opening.

13. A gas burner head substantially as hereinbefore described with reference to Figures 1 to 3, Figures 4 and 5, Figures 6 to 8, or Figure 9.