GB2182131A - Burners for gas fires and/or convectors - Google Patents

Abstract

Hollow burner blades 44, 48, 52, etc, having fuel/air mixture outlets in their upper surfaces are carried by a common pipe or duct 30 into which air is entrained by gas supplied through a rear-mounted jet, these blades 44, 48, 52 alternating with support blades 46, 50, etc, onto which locate respective spacer elements 58, 60, 62, 64. The elements are of inverted-u-shape in cross-section, project upwards beyond the tops of the burner blades 40 to 52, are made of moulded ceramic fibres, and serve to support imitation coals 86. The spacers serve to ensure that secondary air can rise between the burners and reach to flames burning in the vicinity of the imitation coals 86 to ensure that the burner assembly does not overheat and efficient simulation of burning coals is achieved. <IMAGE>

Description

SPECIFICATION Burners for gas fires and/or convectors This invention concerns burners for gas fires, and/or convectors, i.e. gas-fired space heaters of the kind wherein air is heated and is caused to issue into a space, such as a room, to be warmed, by convection.

The invention is more particularly concerned with burners for so-called 'coal-effect' or 'log-effect' gas fires, (that is to say fires of the kind in which burner means is provided beneath a bed of imitation coal and/or logs and in operation creates flames above the coal or log bed to give a visual impression that the coal or logs are burning) and/orforso-called 'visual-effect' convectors which in addition to heating by convection as above described, also incorporate a coal-effect or log-effectfeature.

It is already known, more particularly in connection with industrial boilers and large-sized centralheating boilers, to provide a form of gas burner means which comprises a plurality of substantially parallel hollowflat-topped blades provided on a supporting pipe or duct, which may be effectivel constituted by interfitting bosses provided on the blades, so that a gas/air mixture supplied to the pipe or duct is able to emergethrough outlet apertures in the tops ofthe blades. Such a burner has, however, not been suitablefor coal-effect or log-effectfires fora number of reasons.Firstly, they would provide too much aeration forthe gas being burnt, so that instead of creating a yellow highly-visibleflame app ropriate to give the desired simulation ofthe burning of natural coal of logs, they create a short blue flame which does not have the desired visual effect. Additi onally, they would cause overheating (and perhaps deterioration) ofthe imitation coals or logs and the burner itself. Furthermore they do not provide propersupportforthe imitation coals or logs which, in the prior known arrangements, are usually set down on a bed of sand.

An object of the present invention is to provide a construction of burner comparable with the bladed burners above described, but which is particularly suitable for coal-effect and log-effect gas fires or convectors.

With this object in view, the present invention provides a burner construction, for use in a coal-effect or log-effect gas fire or visual effect gas-fired convector, comprising a plurality of substantially parallel hollow burner blades in the tops of which are outlets for combustible gas, characterised by the provision, between each adjacent pair of said burner blades, of at least one separator element of a heat resistant material, said separator elements protruding upwards beyond the level of the blades and providing director indirectsupportforimitation coals and/or logs.

The separator elements are preferably made of ceramic fibre, moulded and fired, may be vacuumformed, pressed, machined from block or made in any other suitable way, and may comprise individual elements, or may form substantially parallel el ements of a separator element grid.

The burner blades and the support blades may be provided on a supporting pipe or duct. Then, the separator elements may, if desired, be shaped to fit to and be supported by the pipe or duct.

Preferably, however, such separator element is inverted-u-shaped in cross-section, and fits onto a respective support blade provided between the respective pair of burner blades. The support blades may each be of construction comparablewiththe burner blades, but with no outlet apertures therein.

This enables the support blades to be produced with the same tools as the burner blades and contributes to economy of manufacture.

With the construction of burner of the invention, the amount of secondary air which can reach the flames created above the imitation coals and/or logs can be determined by the dimension of the spaces or gaps left between the separator elements and the adjacent burner blades.

The ceramic supports will reach high temperatures and incandesce, which will create a radiant bed, sim ilartothatofa real coal fire. This is because the cer amicsupportssupportthe imitation coals and/or logs at a substantial spacing above the burners, thereby ensuring that the gas/air mixture emerging from the burners is not obstructed by the coals or logs and has adequate free space optimum combustion, e.g. to achieve good visual effect. The supports, themselves, radiate heat between one another to give improved heating effect.

The invention will be described further, by way of example, with reference to the accompanying drawings which illustrate a preferred embodiment, it being understood that the following description is il- lustrative and not restrictive, of the scrope of the invention. In the drawings: Figure lisa plan view illustrating a preferred embodiment of the burner ofthe invention, with parts cut away to enable the construction of parts below to be appreciated; Figure2 is an enlarged fragmentary view illustrating detail of burner blades ofthe burner of Figure 1; Figure3 is a sectional end view taken on the line 3-3 of Figure 1; Figure4is a perspective view illustrating one ofthe separator elements of the burner of Figures 1 to 3; and Figures a perspective view, with parts cut away, showing howthe burner of Figures 1 to 4 is set up in a domesticfireplaceand is used in conjunction with a plurality of imitation coal elements.

The illustrated preferred embodiment ofthe burner of the invention is intended for use within a conventional domesticfiregrate, is of atrivet-like construction and comprises a sheet metal surrounding frame, indicated generally at 10, composed of wide sheet metal strips and consisting of a front horizontally-extending panel 12, a rear panel 14substantially parallel with thefront panel 12 butshorterthan the latter, and two side panels 16, 18which connect the corresponding ends of the front panel 12 and rear panel 14 and converge symmetricallyfrom thefront panel 12 towards the rear panel 14, all of these panels having the planes of their metal strips substantially vertical. The front panel 12 has associated with it, at a slight spacing in front, a guard in the form of a decor ativefret20, (see Figure 5).

The frame 10 is supported at a position raised from the ground (i.e. the fireplace surface belowthe burner) if necessary by a pair of rod-like legs 22 extending downwards from the junctions where the two side panels 16, 18 connect with the front panel 12, and a rear support lug 24 which projects downwardly as a tongue-like member substantially centrallyofthe rear panel.The legs 12 and lug 24will be unnecessary for instance when the structure is suspended in a basket orthe like.

Extending between the front panel 12 and rear panel 14, substantially along the central line of symmetry of the frame 10, is what is effectively a large diameter pipe or duct, indicated generally by the numeral 30, composed of a plurality oftube sections 32 of short axial length a first one of which is secured to the rearpanel 1 4 of the frame and is open to an air inlet aperture (notvisible) therein, andthe lastof which is blanked off by a front disc 34 and secured by a boit 36 to the front panel 12 of the frame 10.Interposed between each adjacent pair of the tube sections 32 is a respective blade 38,40,42,44,46,48,50, 52 comprising a hollow casing approximating to isosceles triangular configuration, of short height and disposed with the 'base' ofthe triangle uppermost and the 'apex' ofthe triangle downwardly directed (as will be seen from Figure 5)so that each such blade presents an upwardly-facing top surface 54,56 or edge (see particularly Figures 1 and 2).These blades are parallel to one another, and the blads 40,44, 48 and 52 are of progressively-increasing 'base' length, from the rearto the front of the surrounding frame 10 within which they are located by the pipe or duct so as terminate, at their ends, at app roximatelyequal spacings from the facing surfaces ofthe side panels of the frame. The remaining blades 38,42,46 and 50 are of equal length corresponding to the length ofthe blade 40, so that all of these blades may be made simultaneously. The tube sections 32 may, of course, be provided by bosses formed integrally with the respective blades and interfitting with one another.

As will be seen, each alternate blade 40,44,48 and 52 is a burner blade having, in its top surface or edge, as is illustrated in Figure 2 in detail, a plurality of outlets orapertures preferably cross-shaped piercings 54 each with a surrounding array of holes 56, through which gas/air mixture supplied to the pipeto duct 30 and passing from the latter into such blades, can emerge upwardsforburning.

The other blades, that isto say the equal-length alternate blades 38,42,46 and 50 between the burner blades, are not perforated in anyway in theirtop surfaces, and are support blades, the function of which is to support, between each adjacent pair of burner blades, a respective separator element 58,60,62,64.

As shown in Figure 4, each of these separatorel- ements comprises a elongate body, basically inver ted-u-shaped in cross-section, made for example by moistening, moulding and firming ceramic fibres, vacuum forming, pressing, machining from block, or in any other suitable way. The cross-section of each such body is such asto provide, from below, a channel 68 along the element by which it will fit down onto and locate with its respective support blade 38, 42,46,50. The ends of this channel may, if desired, be blanked off, although they are not so shown in the illustrated case. Midway along its length, each separatoris arched as indicated at66 in Figure so asto clearthepipeorduct30.

The separator elements are dimensioned in their width (i.e. in their direction corresponding to the spacing between the adjacent blades as indicated at 70 in Figure 4so as to leave gaps between theirfront and rearfaces, and the confronting surfaces ofthe respective adjacent burner blades. These gaps serve, in use of the burner, to permit secondary air to pass upwards to flames above the burner, to ensure appropriate combustion ofthe gas supplied by way of the burner blades for achieving good or optimum visual effect, and it will readily be understood that the dimensions of these gaps can be selected as may be desired or practical, by appropriate dimensioning of the separator elements.

Afront support element 72 made ofthe same material as, and in the same way as, the separator elements 58 to 64, is substantially of L-shaped crosssection and is provided, as shown in Figure 5,to fit along the upper edge of the front panel 12 and project down between such front panel and the frontmost burner blade 54.

As has already been mentioned, the rear panel 14 hastherein an air inlet aperturewith which the rear end of the pipe or duct 30 registers to permit airto enterthe pipe or duct 30. Concentricallydisposed within the pipe or duct 30 is a venturi 74 the rear end ofwhich is of flared configuration at 76, so that such flared portion converges to the main part of the venturi 74. A gas supply injector 78 projects through the rear panel 14 and is connected to gas supply piping 80 which includes a control 82 which is manuallyvariable by means of a knob 84 exposed at the front oftheunit.

The burner as described is installed in the fire space of a domesticfiregrate (not shown) in a manner comparable to known burners. Gas supplied to the injector 78 is directed substantially centrally of theventuri 74and entrains airwith itthrough the inlet aperture. The resultant gas/air mixture passes along the venturi 74 and out of the latter into the pipe or duct 30. It then passes into the burner blades 40, 44,48 and 52 and emergesthrough the outlets or apertures 54,56 in the tops of such burner blades and there is burnt, producing flames of the kind which would be produced by burning natural coal or logs.

As shown in Figure 5, the separator elements 58, 60,62,64 protruding above the level of the top edges of the burner blades 40,44,48,52 (which edges are substantially in a common place) serve as supports for imitation coal lumps 86 (and/or imitation logs not shown) which may be such as to become incandescent when heated. The arrangement thus serves to enable such coals and/or logs to be employed in conjunction with a parallel-blade type burner, which has not hitherto been possible.It is particularly important to notethatthe arrangement of the invention provides forthefull combustion to be supported not only by primary air entrained by the gas byway ofthe ven- turi, but also permits secondary air to be drawn up from beneath the burners to contribtite to the combustion.

The invention is not confined to the precise details of the foregoing example and variations may be made thereto. Thus, for instance, it is not essential to the invention that the burner should be surrounded by the frame 10 as described and of course, all ofthe blades may be of differing or of equal lengths. Moreover, the support blades and/orthe sepatator elements may be of differing lengths and/or heights to enable the imitation logs and/or coals to be set up in aesthetically pleasing arrangements. The upper edges or surfaces ofthe separator elements may be grooved, recessed or otherwise shaped for the coals or logs to locate stably therewith.Moreover, the separators may be present as adjacent components of a grid moulded from ceramicfibres or other suitable material and joined at their ends by side-pieces which in turn may be connected by cross piecesto constitute a surround for the separators.

It is, of course, possibleto arrange a pairofthe burners, such as described, or of rectangular configura- tion side-by-side in a single installation. It is notes- setial, of course, for the burner blades to be supported by a common pipe ro duct as in the illustrated case, and these blades, may be supported individually and separately supplied with fuel/air mixture.

Furthermore, the arrangement could be such that the burner blades and support blades extend front-torear ofthe assembly instead of side-to-side as in the illustrated example, in which case the separator elements will correspondingly extend front to rear, if desired with a single member (similarto the member 72 in Figure 5) acrossthefrontofthe unit.

The initial coals and/or logs may, if desired be indirectly supported by the supports, for example by use of metal gauge or othersuitable perforated material.

The separator elements may be located in place in any suitable manner and it is not essential that they should engage with respective blades as described above. For instance, they could, if desired, be located by an additional or separate framework, and in the illustrated case, for example, they could be located bytheirendswith lugs orthe like ontheframe 10.

Claims (12)

1. A burner construction, for use in a coal-effect or log-effect gas fire or visual effect gas-fired convector, comprising a plurality of substantially parallel hollow burner blades in thetops of which are outlets for combustible gas, characterised by the provision, between each adjacent pair of said burner blades, of at least one separator element of a heat resistant material, said separator elements protruding upwards beyond the level of the blades and providing direct or indirect support for imitation coals and/or logs.

2. A burner construction as claimed in claim 1 in which the separator elements are made of ceramic fibre, moulded and fired.

3. A burner construction as claimed in claim 1 or 2 wherein the separator elements comprise individual elements.

4. A burner construction as claimed in claim 1 or 2 wherein the separator elements form substantially parallel elements of a separator element grid.

5. A burner construction as claimed in any preceding claim wherein each such separator element is inverted-u-shaped in cross-section, and fits onto a respective support blade provided between the respective pair of burner blades.

6. Aburnerconstruction as claimed in claim 5 wherein the support blades are similar two the burner blades, but with no outletaperturestherein.

7. A burner construction as claimed in any preceding claim wherein the burners are enclosed by a surrounding frame.

8. A burner construction as claimed in claim 7 wherein the frame comprises a front panel, a shorter rear panel, and side panels connecting the front and rear panels and converging towards the rear panels.

9. A burner construction as claimed in claim 5 or of claims 6,7 and 8wherein the burner blades and the support blades are provided on a common support pipe or duct.

10. A burner construction as claimed in claim 8 and 9 wherein the support pipe or duct extends between the front and rear panels oftheframe.

11. A burner construction as claimed in claim 9 or 10 wherein the support pipe or ductcommunicates with the interiors of the burner blades and is open to an air inlet, a gas injector projecting into a venturi in the pipe or duct.

12. A burner construction, for use in a coal effect or log-effectfire orvisual effect gas convectorsub- stantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.