GB2345127A

GB2345127A - Decorative effect gas fires

Info

Publication number: GB2345127A
Application number: GB9828259A
Authority: GB
Inventors: David James Izzard
Original assignee: JONES JOAN ELIZABETH
Current assignee: JONES JOAN ELIZABETH
Priority date: 1998-12-22
Filing date: 1998-12-22
Publication date: 2000-06-28
Also published as: GB9828259D0

Abstract

Gas supply means 10 for a decorative effect gas fire 12 comprise a Venturi 14 to aerate a gas supply 16 with primary air 18, and are adapted to combine, with the gas supply 16 aerated by the Venturi 14, being aerated gas 20, neat or less aerated gas 22. The gas supply means 10 comprises by-pass means 40 (Figure 2) adapted to cause said neat or less aerated gas 22 to be tapped at junction 44, to by-pass at least part 42 of the Venturi 14, and to enter the Venturi 14 at a region (inlet 23) where it can combine with gas 20 aerated by the Venturi 14. The by-pass means 40 comprise control means 52, 54 for controlling the gas flow through pipe 50 to inlet 23. The control means 52, 54 comprise a user-operable tap 54 (to choose yellow or colourless flames, and with a hinged cover to avoid confusion with the main gas control 48) and/or a plug 52 inserted in the pipe 50 and having a hole 56 through the plug 52 to pass and control said gas flow. The manufacturer can provide different plugs 52 with respective hole sizes. The Venturi 14 has a curved elbow 60 just prior to its outlet 58, and the combination of gas 22 with aerated gas 20 occurs just prior to said elbow 60. The gas supply means 10 may comprise a Venturi 114 adapted to bolt onto a burner pan 126 to be attached thereto, to supply gas thereto.

Description

TITLE :"Decorative Effect Gas Fires" BACKGROUND This invention relates to decorative effect gas fires, and more particularly those provided with gas supply means comprising a Venturi device to aerate the gas. Such fires may simulate the effect of burning coal or logs, or at least produce similar flames.

The Venturi gives a"clean"bum, (though this is a blue, almost colourless flame,) with very low levels of CO/C02 ratio (e. g. a maximum ratio of 0.01); which may, for example, be a 50% improvement on the combustion level of non-Venturi burners. The combustion level is the efficiency or"cleanness"of burning and corresponds to the degree to which the flames are blue (good/efficient combustion) or yellow (poor/incomplete combustion), which in tum depends upon the amount of (primary) aeration.

It has been known for many years to use such a Venturi in a decorative effect gas fire because this gives good aeration and combustion and provides flames that are colourless, very hot, and firm rather than floppy. However, in order to obtain yellowing of the flames in order to simulate the effect of a solid fuel fire, the ingress of air at the Venturi inlet is restricted by moving the injector (gas supply jet) for feeding neat gas into the inlet of the Venturi closer to the Venturi inlet than the optimum for good aeration and clean burning. This reduction of aeration reduces the bumer outlet port pressure, making the flames floppier, which gives worsening combustion and increased sooting as the simulated coals are piled on. The combustion level of the flames is then found to be unstable and difficult to control. As the injector is moved closer to the Venturi mouth, the flames in the fire go from a stable blue form to a limp yellow form, tending towards bad combustion, inefficient burning, and a bad CO/C02 level. This has the unfortunate effects that the combustion and heating output are poor, the shape, size and degree of yellowing of the flames cannot be precisely controlled, and the flames are unstable and too floppy. As a result, while fires having such Venturi gas supply means have been made and sold over a period of many years, they have not been particularly satisfactory. Additionally, the use of a Venturi has added substantially to the tooling and/or manufacturing costs of the burner.

THE INVENTION According to various aspects of the invention, there are provided a method of producing a live fuel effect using a gas burner, gas supply means for a decorative effect gas fire, and such a fire, as claimed in claims 16,1 and 2 respectively.

Embodiments thereof have the advantage that they can provide an acceptable degree of realism with a much hotter flame than previous fires having the same degree of realism tested by the present inventor.

Use of a Venturi gives a very clean (colourless) burn and the addition of neat gas, according to the present embodiments, allows fine control of the amount of yellowing whilst monitoring the yellowing to an adequate degree. The Venturi maximises the burner outlet port pressure, which gives a greater degree of flexibility and control of flame colour, while still passing modern, stringent CO/C02 and sooting standards.

Thus, it has been found possible to obtain much better control of the combustion level and flame colour, and also an improvement (a substantial reduction) in the CO/C02 ratio. Injection of neat gas at a later stage than the inlet mouth of the Venturi has been found to give a much larger range of stable flame, with an increasing yellow top that extends down the flame as the amount of neat gas supplied is increased, until it reaches a point of poor combustion (comparable with that of the prior case of restricted aeration of the Venturi inlet). It is found that, within this range, there is a wide sub-range of acceptably orange/yellow flame with good combustion. The arrangement can be set so that it produces substantially no sooting whilst still giving this coloured flame, well within present test standards that allow only a minute amount of soot. The features of claim 3 provide a particularly efficient and economical way of putting this into effect.

The features of claims 4 to 7 provide a major additional advantage, in that they allow the type (mainly colour) of flame to be pre-set and/or varied between very yellow and almost colourless, by the manufacturer and/or user. Preferably, the Venturi is supplied with gas from a multi-hole injector having a supply pipe with outer diameter 8 mm and inner diameter 6 mm. The supply pipe for injecting neat gas into the Venturi near its outlet may have the same inner and outer diameters as the supply pipe to the main injector to the Venturi inlet. The flow cross-section for this neat gas must then be severely limited. This is ensured by inserting a plug into the supply pipe for this neat gas, the plug having a central hole of suitable diameter. For a particular maximum yellow effect, the size of this hole seems to be fairly well related to the bumer-head surface area. Indeed, in substance, the required hole size for this condition nearly always seems to be the same, regardless of the shape of the burner-head surface area. For example, for a burner-head surface area of 150 to 200 sq in (950 to 1300 sq cm), it appears that the hole diameter for this condition should be in the range 2 to 3 mm, preferably about 2.5 mm.

The features of claims 8 to 10 appear to provide substantially improved flames compared with the use of embodiments not employing these features. Preferably, the neat gas is injected into the aerated gas in the region of the outlet of the Venturi, preferably just before the outlet. It is surmised that, with the present embodiments, the neat gas forms into many small concentrations dispersed throughout the aerated gas, and this gives the desirable yellow effect coupled with a very hot blue flame, in a stable and controllable manner. If the neat gas is introduced substantially later than the outlet of the Venturi, it tends to give unstable and uncontrollable flames. It is surmised that, in this case, the gas forms into a few large concentrations instead of being dispersed in small concentrations throughout the aerated gas.

The features of claims 11 and 12 can be used to improve heating efficiency.

The features of claim 13 can provide gas supply means which may be attached readily to a large variety of burners, and also enable use of a Venturi without adding substantially to the tooling and/or manufacturing costs of the burners. The features of claim 13 may be considered an invention in their own right independently of the preceding claims; and according to another aspect of the invention there are provided gas supply means for a decorative effect gas fire, said means comprising a Venturi to aerate a gas supply with primary air, characterised in that said gas supply means are attached, or adapted to be attached, to a bumer pan to supply gas thereto.

The features of claims 16 to 26 and 32 provide corresponding advantages to those recited above in relation to claims 1 and 3 to 13 respectively.

Further aspects of the invention provide a bumer and method as claimed in claims 29 and 32.

PARTICULAR DESCRIPTION RELATING TO DRAWINGS Reference will now be made by way of example to the accompanying drawings, in which: Figure 1 is a schematic side view cross-section of a bumer incorporating a Venturi and embodying the invention; Figure 2 is a schematic plan view of the Venturi of Figure 1 and associated gas circuitry; Figures 3,4 and 5 are, respectively, a schematic side view cross-section corresponding to Figure 1, a plan view and a rear elevation of a bolt-on Venturi gas supply means embodying the invention, alternative to the Figure 1 embodiment, and usable in the gas supply circuit of Figure 2; and Figure 6 is a schematic cross-section taken in the same plane as Figure 3, for bolting on thereto of the gas supply means of Figures 3,4 and 5.

In the drawings, three-figure references denote items similar to, or having a similar function to, items having the same reference but without the first of the three figures; e. g. items 14 and 114 are similar and function similarly.

Referring to the drawings, gas supply means 10 (illustrated as that portion of Figure 1 shown below the close-dotted line) for a decorative effect gas fire 12 (illustrated schematically by the chain-dotted line in Figure 1 together with everything else shown in Figure 1) comprise a Venturi 14 to aerate a gas supply 16 with primary air 18, and are adapted to combine, with the gas supply 16 aerated by the Venturi 14, being aerated gas 20, neat or less aerated gas 22. The adaptation is a threaded hole 23 acting as an inlet 23 for gas 22. The Venturi 14 has a split along a horizontal plane 24, and its upper portion 25 is formed integrally with a burner pan 26; its lower portion 27 is then attached to upper portion 25. The gas supply means 10 comprise the Venturi 14 and an injector 28 being the multi-hole injector having a supply pipe 30 mentioned above. The fire 12 comprises the gas supply means 10, the burner pan 26, a baffle 32, and a gas-impermeable insulating blanket 34 with passages 36 to pass upwards the aerated gas admixture 38, which will then be drawn backwards (to the left, as seen in Figure 1) over blanket 34 by the flue action of the fire 12.

Thus, the decorative effect gas fire 12 is provided with gas supply means 10 comprising a Venturi 14, and the fire 12 is adapted to combine, with the gas supply 16 aerated by the Venturi 14, being aerated gas 20, neat or less aerated gas 22.

The gas supply means 10 comprises by-pass means 40 (Figure 2) adapted to cause said neat or less aerated gas 22 to be tapped as part of gas supply 16 and by-pass at least part 42 of the Venturi 14 from a region (junction 44) before the Venturi 14 to a region (inlet 23) where it can combine with gas 20 aerated by the Venturi 14.

Mains supply gas 46 is led through the usual user main control 48 for the gas fire 12 to constitute the aforesaid gas supply 16 which feeds into junction 44, from whence most of it passes to injector 28 as aforesaid, and part of it is tapped off through by-pass means 40, comprising a gas pipe 50, and passes to inlet 23.

The by-pass means 40 comprise control means 52,54 for controlling the gas flow through by-pass means 40 to inlet 23. The control means 52,54 comprise a plug 52 inserted as a separate short section in the pipe 50 having a hole 56 through the plug 52 to pass and control said gas flow, as explained in more detail above. The manufacturer can provide different plugs 52 with respective hole sizes, e. g. for controlling (pre-setting) the by-pass gas flow 22 and hence the flame colour if no tap is provided.

The control means 52,54 comprise means 54 adapted to enable user control of said by-pass gas flow. Means 54 comprise a user-operable tap 54 which may be simply on-off (so that the user can choose yellow or substantially colourless flames, e. g. the latter for initially heating the room at maximum rate) or may be adjustable to constitute adjustable means 54 suitable for adjusting said by-pass gas flow 22 and hence the degree of yellowing of the flames. The tap 54 may be brought out to the front or side of the fire 12, e. g. adjacent the main control 48, though possibly less accessible (e. g. by having a hinged cover) than main control 48 in order not to be confused therewith.

The Venturi 14 has an outlet 58, and the arrangement is adapted for the combination of gas 22 with aerated gas 20 to occur in the region of said outlet 58.

As shown in Figure 1, the arrangement is adapted for the combination to occur just prior to said outlet 58. More particularly, the Venturi 14 has a curved elbow 60 just prior to its said outlet 58, and the arrangement is adapted for the combination to occur just prior to said elbow 60. These features are found to give good gas flow, appropriate mixing, and good controllability of yellowness of the flames.

The arrangement is adapted for the primary aeration to be substantially complete aeration by placing injector 18 at a readily ascertainable, appropriate distance from inlet 62 of Venturi 14. By tapping gas 22 at junction 44, the arrangement is adapted for the less aerated gas to be neat gas from a gas supply 16 to the Venturi 14, which in this case is also a gas supply 16 to the gas supply means 10, but it could alternatively be tapped from the mains supply 46 to the fire 12.

In another embodiment, as illustrated in Figures 3 to 6, the gas supply means 10 comprises a Venturi 114 adapted to bolt onto a bumer pan 126 to be attached thereto, to supply gas thereto. As before, Venturi 114 is split along horizontal plane 124 so that it can be manufactured in two parts which are then attached together. The outlet 158 of the Venturi 114 has as an upstanding rim 64, which fits into a hole or cutout 66 in the base of burner pan 126, to which it is attached by means of bolts (not shown) passed through holes 67 in the base of burner pan 126 and screwed into threaded holes 68 in Venturi 114. The burner pan 126 is of 1 mm coated sheet steel 127 with an inverted square U-shaped bracket 70 that supports a 6 mm board 72, itself supporting a 12 mm insulating blanket 74, board 72 being attached to bracket 70 with a self-tapping screw 76 and being fixed to the front of burner pan sheet steel 127 by mastic 78. In the burner pan 126, a burner head 18 of 1 mm sheet mild steel is fixed to sheet steel 127 by spot welds 82 at the rear and sides of burner pan 126 and a weld 84 at the front of burner pan 126, and is provided with mesh 86 to prevent lightback, and supports a 25 mm blanket 134.

In operation of the above, there is provided a method of producing a live fuel effect using a gas bumer (comprising burner pan 26,126), in which gas 16 is aerated by means of a Venturi 14,114, and the aerated gas 20 is combined with neat or less aerated gas 22, which by-passes at least part of the Venturi 14 from a region (of injector 28) before the Venturi 14 to a subsequent region (of inlet 23) where it combines with gas 20 aerated by the Venturi 14. The by-passing gas flow 22 is controlled in the course of the by-passing, and passes through and is controlled by a hole 56 through a plug 52 in the course of the by-passing, is controlled by the user in the course of the by-passing, and is adjusted to adjust the by-passing gas flow 22 in the course of the by-passing. The combination of neat gas 22 with aerated gas 20 occurs in the region of an outlet 58 of the Venturi 14, just prior to said outlet 58, and just prior to a curved elbow 60 of the Venturi 14 just prior to said outlet 58. The primary aeration is substantially complete aeration. The less aerated gas 22 is substantially neat gas and/or gas from a gas supply 16 to the Venturi 14, gas supply means 10 and/or fire 12.

The gas bumer 26,126 for producing a live fuel effect is adapted to effect such methods as just described.

There can thus be provided a method of producing a gas burner, e. g. as described above, in which a separate gas supply means (10, but with Venturi 14 replaced by Venturi 114) comprising a Venturi 114 is attached to a burner pan 126 to supply gas thereto.

It will be apparent to one skilled in the art, that features of the different embodiments disclosed herein may be omitted, selected, combined or exchanged and the invention is considered to extend to any new and inventive combination thus formed.

Claims

CLAIMS 1. Gas supply means for a decorative effect gas fire, said means comprising a Venturi to aerate a gas supply with primary air, characterised in that said means are adapted to combine, with the gas supply aerated by the Venturi, neat or less aerated gas.
2. A decorative effect gas fire provided with gas supply means comprising a Venturi, characterised in that the fire is adapted to combine, with the gas supply aerated by the Venturi, neat or less aerated gas.
3. Means or a fire as claimed in claim 1 or 2, characterised in that it comprises by-pass means adapted to cause said neat or less aerated gas to by-pass at least part of the Venturi from a region before the Venturi to a region where it can combine with gas aerated by the Venturi.
4. Means or a fire as claimed in claim 3, characterised in that the by-pass means comprise control means for controlling the gas flow therethrough.
5. Means or a fire as claimed in claim 4, characterised in that the by-pass means comprise a gas pipe and the control means comprise a plug in the pipe having a hole through the plug to pass and control said gas flow.
6. Means or a fire as claimed in claim 4 or 5, characterised in that the control means comprise means adapted to enable user control of said by-pass gas flow.
7. Means or a fire as claimed in any one of claims 4 to 6, characterised in that the control means comprise adjustable means suitable for adjusting said by-pass gas flow.
8. Means or a fire as claimed in any one of claims 1 to 7, the Venturi having an outlet, characterised in that the gas supply means or fire is adapted for the combination to occur in the region of said outlet.
9. Means or a fire as claimed in claim 8, characterised in that it is adapted for the combination to occur just prior to said outlet.
10. Means or a fire as claimed in claim 9, characterised in that the Venturi has a curved elbow just prior to its said outlet, and the gas supply means or fire is adapted for the combination to occur just prior to said elbow.
11. Means or a fire as claimed in any one of claims 1 to 10, characterised in that it is adapted for the primary aeration to be substantially complete aeration.
12. Means or a fire as claimed in any one of claims 1 to 11, characterised in that it is adapted for the less aerated gas to be substantially neat gas and/or gas from a gas supply to the Venturi, gas supply means or fire.
13. Means or a fire as claimed in any one of claims 1 to 12, characterised in that it comprises gas supply means as claimed in claim 1 attached, or adapted to be attached, to a bumer pan to supply gas thereto.
14. Gas supply means or a fire substantially according to any example hereinbefore described.
15. Gas supply means or a fire substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.
16. A method of producing a live fuel effect using a gas burner, in which gas is aerated by means of a Venturi, characterised in that the aerated gas is combined with neat or less aerated gas.
17. A method as claimed in claim 16, characterised in that said neat or less aerated gas by-passes at least part of the Venturi from a region before the Venturi to a subsequent region where it combines with gas aerated by the Venturi.
18. A method as claimed in claim 16 or 17, characterised in that the by-passing gas flow is controlled in the course of the by-passing.
19. A method as claimed in claim 18, characterised in that the by-passing gas flow passes through and is controlled by a hole through a plug in the course of the by-passing.
20. A method as claimed in claim 18 or 19, characterised in that the by-passing gas flow is controlled by the user in the course of the by-passing.
21. A method as claimed in any one of claims 18 to 20, characterised in that the control means is adjusted to adjust the by-passing gas flow in the course of the by-passing.
22. A method as claimed in any one of claims 16 to 21, characterised in that the combination occurs in the region of an outlet of the Venturi.
23. A method as claimed in claim 22, characterised in that the combination occurs just prior to said outlet.
24. A method as claimed claim 23, characterised in that the combination occurs just prior to a curved elbow of the Venturi just prior to said outlet.
25. A method as claimed in any one of claims 16 to 24, characterised in that the primary aeration is substantially complete aeration.
26. A method as claimed in any one of claims 16 to 25, characterised in that the less aerated gas is substantially neat gas and/or gas from a gas supply to the Venturi, gas supply means or fire.
27. A method of producing a live fuel effect using a gas bumer, substantially according to any example hereinbefore described.
28. A method of producing a live fuel effect using a gas bumer, substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.
29. A gas bumer for producing a live fuel effect, characterised in that it is adapted to effect a method as claimed in any one of claims 16 to 28.
30. A gas bumer substantially according to any example hereinbefore described.
31. A gas bumer substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.
32. A method of producing a gas burner as claimed in any one of claims 29 to 31, characterised in that a separate gas supply means comprising a Venturi is attached to a bumer pan to supply gas thereto.
33. A method of producing a gas bumer substantially according to any example hereinbefore described.
34. A method of producing a gas bumer substantially according to any example hereinbefore described with reference to and illustrated in the accompanying drawings.