GB2322188A - Flame effect simulation - Google Patents

Abstract

A combustion image generator, for a flame effect electric fire (10), uses clustered LED's (14) in apertures and/or pockets (16) shaped or embedded within the contours of a profiled fuel bed layer (12), with reflector rear and side walls (16) and flame-shaped fine-mesh, gauze fabric upstands (17), the LED's being illuminated sporadically, by a random pulse controller switch to create a flickering flame visual effect. A reciprocating shutter array, with multiple reflector and/or refractor vanes may also be used for flame flicker effect.

Description

Combustion Flame Effect Simulation This invention relates to optical effects and is particularly, but not exclusively, concerned with the simulation of combustion, such as the flames from a solid fuel (say, coal or wood) fire.

As such, the invention finds application in fires, particularly those relying upon a radiant or convector heater element, whether gas fired, electric or otherwise, to create the visual effect or appearance of a burning solid fuel fire.

Broadly, the intention is to engender 'suspended disbelief', since there is no doubt as to the artificial nature of the fire and ultimate source of heat - but nevertheless a sensation of warmth can be created by appropriate flame imagery.

In practice, a burning fuel bed generates an underlying incandescence, reflecting a stable ongoing combustion stage, in which the heat given out by burning fuel is sufficient progressively to ignite as yet unburnt fuel and preserve combustion.

Superimposed upon this glowing fuel bed are both continuous and/or random intermittent bursts of flame from intermediate incomplete combustion stages- such as burning of (waste) gases 'flared' as combustion by-products.

A conventional, so-called 'fuel effect' fire, relies upon a part-translucent profiled layer, typically.a fibreglass (stiffened) sheet moulding, rendered with a coloured image, illuminated by an underlying light source, such as from a clear or colour-coated tungsten filament or fluorescent lamps.

A common elaboration upon static background illumination of the fuel bed is a superimposed flickering light effect.

Typically this flicker is produced by intervening (light reflector) vanes between the lamp and fuel effect, rotated actively by a motor or passively by convective hot air currents from the 'background' lamp.

Various reflector and projection techniques have also been employed, in conjunction with such flickering fuel bed illumination, for an enhanced combination glowing fuel and 'shooting' flame effect - but these have proved of limited realism.

Reliance upon electro-mechanical contrivances to reproduce a flicker effect risks adding complexity and cost, with attendant reliability and maintenance problems, not necessarily justified by a 'convincing' optical image or visual effect.

Various attempts have been made hitherto to use electronic displays, including neon lights, but these have added complexity and cost of another kind, disproportionate to the resulting appearance.

According to one aspect of the invention, a (combustion) image generator comprises a profiled translucent fuel bed layer, rendered with a coloured (solid fuel) image, a plurality of apertures, integrated within contours of the profiled layer, clusters of electronically triggered light sources, adjacent said apertures, and illuminated, through a programmable controller switch, to provide multiple, localised, individual bursts of light, to replicate a flame, and imparting a flickering flame optical effect, apparently emergent from the fuel bed layer.

Such apertures are desirably at the foot of upstands in the fuel bed layer, which serve as reflector walls for light emerging from the apertures.

Preferably, the apertures are the mouths of discrete pockets integrated within the contours of the profiled fuel bed layer, and with peripheral reflector walls, the light sources being fitted within said pockets, and the emergent light being shaped by the reflective pocket walls, The shape, size and location of the apertures and/or pockets, and in particular their plan area, determines the emanating light pattern.

Similarly, the reflectivity of the pocket (rear and side) walls, or the localised fuel bed layer upstands from the apertures, affects the emergent light path.

For controlled contrast with the general level of background illumination, it is convenient for the (rear and side) pocket walls, and/or the local fuel bed upstands, to form a pronounced, localised 'escarpment' in the fuel bed contour - which in turn casts a shadow on a rear reflector wall.

Such fuel bed surface transitions are concealed cosmetically by merging into, say, a contour representing, say, a protruding lump of coal or log, according to the fuel effect.

In order to enhance the localised, periodically illuminated flame effect, supplementary (flame-shaped) fine-mesh, gauze fabric (eg nylon) upstands may be fitted to the (rear) pocket walls, in the light path of the associated LED clusters.

The depth, curvature (in plan and eievation) and inclination of such reflector upstands can be used to adjust the height and spread of reflected flame effect light.

The light sources are preferably high-intensity light-emitting diodes (LED's).

Such LED's may generate a localised pencil or flood beam of light which can be directed.

Colour-tinted LED's are desirable, to impart appropriate flame colours, such as red, orange, blue and green tinges.

Clear LED's are also desirable to provide greater light output and raise general background illumination levels.

A programmable controller switch may vary electronically the intensity, frequency and overall pattern of multiple light source switching - enabling the flame effect to be varied to suit individual installations, ambient light and user preference.

An intermediate diffuser screen, such as of fine-mesh, gauze fabric (eg nylon), may be stretched taut, as an (angled) viewing plane, from the profiled layer, to diffuse and spread emergent light over a larger area - and soften otherwise stark or abrupt lighting transitions.

Such a gauze diffuser screen may extend over the width of the fuel bed and to the height of the attendant enclosure, from an intermediate position in the depth of the fuel bed.

Desirably, the screen has a shallow incline to a back plane of the enclosure.

The degree of incline determines the height and spread of reflected flame effect light.

A rear reflector may be fitted to the back wall of the enclosure, to promote the forward re-direction of light for viewing from the front.

Supplementary localised multiple individual light sources may be deployed, say in multi-coloured clusters, to direct their light directly towards such a rear reflector.

A translucent, clear or colour-tinted, front viewing screen may be fitted - desirably with a matt (front or rear) surface for diffusion of viewed light.

In some variants, supplementary mobile reflectors may be used to create a dynamic varying light effect.

Thus, for example, mutually reciprocating linear shutters of multiple individual reflector vanes may be disposed between the fuel bed and its attendant (underlying) illumination.

There now follows a description of a particular embodiment of the invention, by way of example only, with reference to the accompanying drawings diagrammatic and schematic drawings, in which: Figure 1 shows a part cut-away, part-sectional, front perspective view from one side of a flame effect electric fire according to the invention; Figure 2 shows a sectional side elevation of the flame effect fire of Figure 1; Figure 3 shows a variant of the fire shown in Figures 1 and 2, with a supplementary intermediate fabric light diffuser screen; Figure 4A shows a sectional side elevation of a variant of the fires shown in Figures 1 through 3, with a reciprocating light shutter; and Figure 4B shows a sectional front elevation of the reciprocating shutter module of Figure 4A.

Referring to the drawings, a flame effect fire 10 comprises a sheet metal housing 11 defining an enclosure, in which is fitted a combustion flame effect generator, including a translucent profiled fuel bed layer 12 with bespoke lighting.

A steady background illumination is provided by an array of tungsten filament lamps 23, with clear glass, or with red or orange colour coating, mounted in a tray 21 immediately beneath the fuel bed 12.

An intermittent flickering light effect is superimposed upon the background illumination, through an array of LED's 14, integrated physically and closely blended optically with the fuel bed 12.

Thus, embedded within the contours of the fuel bed 12 are a series of recesses or pockets 16, with upstanding reflector (rear and side) walls 19.

To enhance the perceived flame effect, flame-shaped reflector upstands 17, of finemesh, gauze fabric (eg nylon) are fitted to the pocket walls 19.

The upstands 17 and pockets 16 are configured co-operatively to control the flame effect lighting.

Fitted within each of the pockets 16 are clusters of high intensity LED's 14, grouped in colour-tinted and clear combinations, to create a convincing overall multi-coloured flame effect - including in particular the blue-green hues commonly absent from conventional red-orange flame effect fires.

Different colour groupings, for example selected from appropriate fire colours, such as red, orange, blue and green, etc, are empioyed for greater variation and realism in the overall effect.

The LED's 14 are connected to a programmable electronic controller switch 31 and are switched on and off randomly to evoke a natural flickering light effect, which is tailored into a flame appearance by the reflective walls of the pockets 16 and the upstands 17.

Colour variation is also achieved through programmable switching of the LED clusters.

A sound chip is incorporated under the control of the switch 31 to generate, in conjunction with the flickering flames, background sound (such as crackling) evocative of combustion through a loudspeaker 27.

A translucent, clear or colour-tinted, front viewing screen 29 has a matt finish (front and/or rear) surface to achieve a diffuser action, which slightly softens and blends the flame effect with the background illumination.

A rear reflector wall 18 provides a back projection of dedicated clusters of LED's 15, rearwardly directed from the back of the profiled bed 12, to create a supplementary combined flickering 'searchlight' flame effect and background glow.

A supplementary, intermediate fine-mesh, gauze fabric screen 33 (eg of nylon), could be fitted between the front viewing screen 29 and rear reflector wall 18, as shown in Figure 3.

The intermediate screen 33 is slightly inclined (in this case rearwardly, although forwardly would be possible) from upright, to capture light projected from one or both the LED clusters 14 and 15, and create a visual depth, height and spread of flame effect lighting.

Figure 4 shows a reciprocating shutter variant 45, which may be used in conjunction with, or instead of, electronic flicker.

Two, closely-spaced, reflector and/or refractor) shutters 34, 35 are disposed across the light path from a (clear-glass), tungsten filament bulb array 37, and are reciprocated relatively through an eccentric drive 39 by an electric motor 41.

In fact, only one (eg the lower) of the shutters (34, 35) need be moved, longitudinally, the other (uppermost one 35) being kept stationery.

Each shutter 34, 35 comprises a grid of spaced reflector and/or refractor vanes 38, individually angled across the light path from the bulb array 37, to create a multitude of reflections and/or refractions, varying as the shutters 34, 35 move relatively.

Additional reflector and/or refractor elements 43, spaced from the reflector grids 38, can be used to create additional light paths intersecting the vanes 38.

The relative disposition - ie position and angle - of optical elements may be used for control of local optical interaction and overall effect.

The combined, co-operative effect of the shutters 34, 35 and elements 43 is to create a flickering light effect, through optical, rather than electronic means. Nevertheless, a flickering switched electronic (LED) illumination and a reciprocating shutter may be combined.

The principles of the lighting effect generator described for evoking fuel combustion may be used to create other (decorative) effects and may be implemented in the absence of any heat generation.

To this end, the fuel bed, diffuser and viewing screens could be configured to allow viewing from different directions and standpoints.

Component List 10 flame effect fire 11 housing 12 profiled (fuel bed) layer 14 LED cluster 15 LED cluster 16 pockets 17 mesh fabric upstands 18 rear reflector wall 19 reflector (rear and side) walls (pockets 16) 21 tray 23 lamps 27 loudspeaker 29 front viewing screen 31 electronic controller switch 33 intermediate gauze screen 34 (lower, reciprocating) shutter 35 (upper) shutter 37 lamp array 38 vanes (shutters 34, 35) 39 eccentric drive 41 electric motor 43 reflector/refractor elements 45 reciprocating shutter variant

Claims (12)

1. Claims 1.

   A (combustion) image generator, comprising a profiled translucent fuel bed layer, rendered with a coloured (solid fuel) image, a plurality of apertures, integrated within contours of the fuel bed layer, clusters of electronically triggered light sources, adjacent said apertures, and illuminated, through a programmable controller switch, to provide multiple, localised, individual bursts of light, to replicate a flame, and imparting a flickering flame optical effect, apparently emergent from the fuel bed layer.
2. 2.

   A combustion image generator, as claimed in Claim 1, wherein said apertures are located at the foot of upstands in the fuel bed layer, which serve as reflector walls for light emerging from the apertures.
3. 3.

   A combustion image generator, as claimed in either of the preceding claims, wherein said apertures are the mouths of discrete pockets integrated within the contours of the profiled fuel bed layer, and with peripheral reflector walls, the light sources being fitted within said pockets, and the emergent light being shaped by the reflective pocket walls,
4. 4.

   A combustion image generator, as claimed in any of the preceding claims, wherein the shape, size and location of said apertures and/or pockets, and in particular their plan area, are configured to determine the emanating light pattern.
5. 5.

   A combustion image generator, as claimed in any of the preceding claims, wherein the reflectivity of the pocket (rear and side) walls, or the localised fuel bed layer upstands from the apertures, is configured to determine emergent light paths.
6. 6.

   A combustion image generator, for a flame effect fire (10), comprising a profiled translucent fuel bed layer (12), rendered with a coloured (solid fuel) image, a plurality of pockets (16), integrated within contours of the profiled layer, with peripheral reflector walls (19), clusters of electronically-triggered light sources (14), fitted into said pockets, and illuminated, through a programmable controller switch (31), to provide multiple, localised, individual bursts of light, shaped by the pocket walls, to replicate a flame, and imparting a flickering flame optical effect, apparently emergent from the fuel bed layer, when viewed through a front screen (29).
7. 7.

   A combustion image generator, as claimed in any of the preceding claims, incorporating fine-mesh, gauze fabric (eg nylon), flame-profiled upstands (17) from the pocket walls, to supplement the flame effect.
8. 8.

   A combustion image generator, as claimed in any of the preceding claims, incorporating an intermediate fine-mesh, gauze fabric screen, between the fuel bed layer and a rear reflector wall.
9. 9.

   A combustion image generator, comprising one or more reciprocating shutters (34, 35), between a light source (37) and viewing screen (29), the or each shutter incorporating a grid, of angled reflector and/or refractor strips (38), to create a multitude of intersecting light paths.
10. 10.

    A combustion image generator, combining electronic switched (LED) illumination, as claimed in any of Claims 1 through 8, and a reciprocating shutter, as claimed in Claim 9.
11. 11.

    A combustion image generator, substantially as hereinbefore described, with reference to, and as shown in, the accompanying drawings.
12. 12.

    A fire incorporating a combustion image generator, as claimed in any of the preceding claims.