GB2213924A

GB2213924A - Burner for fuel-effect fire

Info

Publication number: GB2213924A
Application number: GB8900845A
Authority: GB
Inventors: Ian Deakin
Original assignee: Glow Worm Ltd
Current assignee: Glow Worm Ltd
Priority date: 1988-01-16
Filing date: 1989-01-16
Publication date: 1989-08-23
Anticipated expiration: 2009-01-16
Also published as: GB8900845D0; GB8800969D0; GB2213924B

Abstract

A method of producing a live fuel-effect for a gas fire involves supplying different gaseous fuel mixtures to different regions of the burner such that on ignition flames of different characteristic are produced at the respective regions. The gas burner comprises a housing 5 a portion 6 of which defines a burner surface and means for introducing into the housing at discrete predetermined locations 10, 11 and 12 gaseous fuel mixtures of different composition. The gaseous fuel mixtures preferably differ in the ratio of gas to air in the mixture. The fuel supplied to inlet 12 may be non-aerated, whereas that supplied to inlets 10 and 11 may be aerated by using suitable injectors. <IMAGE>

Description

Gas Burners This invention relates to gas burners and is especially, but not exclusively, applicable to gas burners for use in so called "live fuel effect" fires, that is to say gas fires which are provided with imitation fuel and are designed in use to produce a visual flame effect simulating t-hat attained by an open coal or log fire.

Most previously proposed forms of gas burner do not produce an aesthetically satisfactory live flame effect as their burning characteristics are unduly uniform. Attempts have been made to improve on the live flame effect by employing a main burner which produces flames for heating purposes and an associated auxiliary burner which produces cooler flames of a different character which are directed into the main flame with a view to altering the visual effect. Such arrangements however require additional space for fitting of the auxiliary burner and provide only limited control over the flame effects which can be attained.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to one aspect of the invention there is provided a method of producing a live fuel effect utilizing a gas burner comprising supplying different gaseous fuel mixtures to different regions of the burner such that on ignition flames of different characteristic are produced at the respective regions.

Preferably the gaseous fuel mixtures differ in the ratio of gas to air in the mixture.

The variation of the gaseous fuel mixture may be attained by mixing within the burner a primary aerated gas supply and a secondary gas supply which is not aerated or aerated to a lesser degree, the secondary supply being introduced into the main supply at selected spaced locations to produce a desired variable flame pattern at the burner surface.

Where the burner surface is other than flat the flame pattern may be further modified by directing the different gaseous fuel mixtures to regions of the burner surface which face in different directions.

The invention also provides a gas burner comprising a housing a portion of which defines a burner surface and means for introducing into the housing at discrete predetermined locations, gaseous fuel mixtures of different composition.

Preferably the burner includes a main gas supply inlet adapted to be supplied with a first gaseous fuel mixture and a secondary gas supply inlet adapted to be supplied with a second gaseous fuel mixture, said secondary inlet being arranged to deliver said second fuel mixture to the chamber in one or more predetermined positions for admixture with the main gaseous fuel mixture. The main fuel inlet may comprise a tube opening into the body of the burner and the secondary fuel inlet may comprise a pipe disposed within the body of the burner and provided with a series of outlet apertures at predetermined locations.

The burner may advantageously comprise a plurality of burner chambers which may be selectively supplied with gaseous fuel mixture for ignition as desired under control of a suitable supply valve or tap whereby to vary the heat output of the burner, said secondary supply pipe being provided with outlet apertures located within any one or more of the main burner sections.

Alternatively separate secondary fuel supply pipes may be connected to each of the chambers of the main burner.

The invention also provides a gas-fired heating appliance incorporating a burner as aforesaid.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which Fig. 1 is a perspective view of a burner construction according to the invention with the burner casing partly broken away to show internal details; and Fig. 2 is a similar view of a modified burner.

Referring to Fig. 1, the burner is adapted for use in a live fuel effect fire and comprises a generally rectangular casing 5 having bottom side and end walls and a perforated upper surface 6 constituting a flame strip at which ignition of gaseous fuel supplied to the burner takes place. Within the main casing 5 is a secondary casing 7 communicating with the central region of the flame strip 6 and defining a central burner chamber. The two end regions 8A and 8B of the casing 5 are interconnected beneath the chamber 7 to form an outer burner chamber. The casing is constructed of metal and is gas-tight save for the perforated flame strip 6.

Main gas supply tubes 10 and 11 enter the burner casing 5 through one end wall, the tube 10 communicating with the outer burner chamber defined by the interconnected end sections 8A and BB, and the tube 11 passing through the section 8A and opening into the central chamber 7. The tubes 10 and 11 are arranged to be supplied in use with a gaseous fuel mixture which is aerated by means of injectors (not shown) disposed adjacent the points of entry to the casing 5 whereby to introduce into either or both of the chambers a primary aerated gaseous fuel mixture which, when ignited at the surface of the flame strip 6, will produce a stable, relatively short, blue flame designed to heat imitation fuel forming part of the fire in which the burner will be mounted in use.Such imitation fuel is generally of a fibrous ceramic nature formed to represent coal or logs. The imitation fuel becomes incandescent on heating by the gas flames and radiates heat from the appliance into the space to be heated. By provision of appropriate controls gaseous fuel may be supplied to the central chamber 7 only, to the outer chambers 8A and 8B only, or to all three chambers dependent on the heat output required from the appliance.

An auxiliary or secondary fuel supply pipe 12 passes through the end wall of the burner casing 5 and through the outer chamber 8A into the inner chamber 7.

The pipe 12 is unperforated in the region extending through the chamber 8A but is provided with a series of spaced perforations or outlet apertures 13 within the chamber 7. In use the pipe 12 is supplied with nonaerated gas or with gas which is substantially nonaerated and which is discharged through the apertures 13 to mix with the main gas supply within the chamber 7 prior to the gas mixture leaving the chamber through the flame strip 6 at which it is ignited. By virtue of the fact that the secondary gas supply is discharged into the chamber 7 at spaced points determined by the location of the apertures 13, incomplete mixing with the main gas supplied through the pipe 11 takes place and the gaseous mixture presented to the flame strip 6 therefore differs at different locations along the surface. As a result when the gaseous mixture is ignited a variable flame effect is produced, those regions where the mixture has been enriched by injection of the neat gas from the pipe 12 burning with a longer more yellow flame which produces an effect similar to that attained by combustion of live fuel.

Fig. 2 of the drawings shows a modified arrangement in which two secondary gas supply pipes 12A and 12B are incorporated, the pipe 12A passing through the outer chamber 8A and being provided with spaced outlet openings 13A within the chamber 7, and the pipe 12B extending completely through the main casing 5 from the chamber 8A to the chamber BB but beneath the chamber 7 and being perforated at those regions which lie within the chambers 8A and BB. In this way the variable flame effect attained in the central region of the burner construction of Fig. 1 can be duplicated in the outer burner regions whereby to provide the ability to control the flame characteristics over the whole length of the burner if desired.It will be appreciated that in this instance appropriate control means will be provided to ensure that no gas is supplied to the pipes 12A or 12B unless there is a simultaneous supply to the associated region of the burner from the main supply pipes 11 and 10.

The embodiments described differ from previously proposed live fuel effect burners in that control of the character of the flame is effected by mixing of different gaseous fuels within the main burner housing. No ignition takes place until the fuel mixtures reach the burner surface and the arrangement is such that only partial mixing takes place within the burner whereby to produce a variable flame effect at the burner surface.

There is no requirement for additional burners mounted externally of the main burner and the desired efffect is attained by control and variation of the gaseous fuel supply before ignition rather than by mixing of previously ignited flames.

Many variations may be made without departing from the scope of the invention. For example considerable conLrol over the flame characLeristics can be attained by appropriate positioning of the auxiliary gas outlets which need not be equispaced but could be arranged in groups at different locations along the length of the burner surface, could be arranged in a random manner or could be confined to selected regions of the burner.

Further control is possible by variation of the size of the outlet apertures, by their positioning relative to the burner surface and by control of the composition and pressure of gas supplied through the secondary supply pipes.

It should also be appreciated that both the main and secondary supply pipes may enter the burner at any desired positions and need not all enter through the same burner walls. The burner may also consist of a single chamber only or of any desired number of separate or interconnected chambers dependent on the intended end use and required output. Any suitable means of ignition and any suitable means for controlling supply of gas mixtures to the main and secondary supplies and to the various chambers, where provided, may be employed.

In some cases the burner may be provided with a curved or other non-flat burner surface. In such cases additional control can be attained by varying the angular direction of the outlets in the secondary supply pipes whereby to direct the enriched mixture through regions of the burner surface facing in different directions and thereby further modify the visual flame effect.

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 method of producing a live fuel effect utilizing a gas burner comprising supplying different gaseous fuel mixtures to different regions of the burner such that on ignition flames of different characteristic are produced at the respective regions.

2. A method according to claim 1 wherein said gaseous fuel mixtures differ in the ratio of gas to air in the mixture.

3. A method according to claim 1 or 2 wherein said variation of the gaseous fuel mixture is attained by mixing within the burner a primary aerated gas supply and a secondary gas supply which is aerated to a lesser degree, the secondary supply being introduced into the main supply at selected spaced locations to produce a desired variable flame pattern at the burner surface.

4. A method according to claim 3 wherein said secondary gas supply is non-aerated.

5. A method according to any preceding claim wherein said flame pattern is further modified by directing the different gaseous fuel mixtures to regions of the burner surface which face in different directions.

6. A method of producing a live fuel effect utilizing a gas burner comprising supplying gaseous fuel mixtures to regions of the burner surface which face in different directions such that on ignition a non-uniform flame structure is produced.

7. A method according to claim 6 wherein different gaseous fuel mixtures are supplied to said regions.

8. A method according to claim 7 wherein said fuel mixtures differ in the ratio of gas to air in the mixture.

9. A method of producing a live fuel effect substantially as hereinbefore described.

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10. A gas burner comprisingthousing a portion of which defines a burner surface and means for introducing into the housing at discrete predetermined locations, gaseous fuel mixtures of different composition.

11. A gas burner according to claim 10 including a main gas supply inlet adapted to be supplied with a first gaseous fuel mixture and a secondary gas supply inlet adapted to be supplied with a second gaseous fuel mixture, said secondary inlet being arranged to deliver said second fuel mixture to the chamber in one or more predetermined positions for admixture with the main gaseous fuel mixture.

12. A gas burner according to claim 11 wherein said main fuel inlet comprises a tube opening into the body of the burner and said secondary fuel inlet comprises a pipe disposed within the body of the burner and provided with a series of outlet apertures at predetermined locations.

13. A gas burner according to claim 12 comprising a plurality of burner chambers which may be selectively supplied with gaseous fuel mixture for ignition as desired under control of a suitable supply valve or tap whereby to vary heat output of the burner.

14. A gas burner according to claim 13 wherein said secondary supply pipe is provided with outlet apertures located within at least one of said burner chambers.

15. A gas burner according to claim 13 wherein separate secondary fuel supply pipes are connected to and have outlet apertures opening into each of said chambers.

16. A gas burner according to claim 14 or 15 wherein said outlet apertures are spaced apart lengthwise of the or each said pipe within the or each associated burner chamber.

17. A gas burner according to claim 16 wherein said outlet aperture are arranged in groups at spaced locations lengthwise of the associated chamber.

18. A gas burner according to claim 16 wherein said outlet apertures are randomly arranged.

19. A gas burner according to any of claims 16 to 18 in which said outlet apertures vary in size.

20. A gas burner according to any of claims 16 to 19 wherein said burner surface is curved and said outlet apertures in the or each said secondary supply pipe are directed in different directions.

21. A gas burner according to any of claims 11 to 20 including injector means for supplying aerated gas to said main gas supply inlet.

22. A gas burner according to claim 21 including means for supplying less aerated gas to said secondary inlet.

23. A gas burner according to claim 21 including means for supplying non-aerated gas to said secondary inlet.

24. A gas burner according to claim 22 including means for varying the composition of gas supplied to the or each said secondary inlet.

25. A gas burner according to any of claims 22 to 24 including means for varying the pressure of gas supplied through the or each secondary inlet.

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

27. A gas burner substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

28. A gas fired heating appliance incorporating a burner according to any of claims 10 to 27.

29. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.