GB2587349A

GB2587349A - Retaining fuel

Info

Publication number: GB2587349A
Application number: GB1913657.1A
Authority: GB
Inventors: Sharman Wayne
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2021-03-31
Also published as: GB201913657D0

Abstract

A device 10 featuring a cage 2 with a hollow interior and multiple through-holes 3 retains solid fuel on a fire grate. The cage has two opposing open ends and ideally comprises a tubular cage of circular or oval cross-section having an unobstructed internal volume that tapers inwardly from one end 4 to the other end 5, with the one end being supported on the fire grate in use. A mesh of wire bars 8 may define the through-holes and ideally the bars account for 10% or less of the surface area of the cage.

Description

RETAINING FUEL

TEHCNICAL FIELD

The present invention relates to a device for retaining solid fuel on a fire grate, and particularly but not exclusively to a device for retaining solid fuel in a domestic stove.

BACKGROUND

Domestic multi-fuel stoves typically comprise a fire grate which provides a surface upon which solid fuel can be arranged. A fire grate comprises a series of apertures which allow oxygen to flow to solid fuel arranged on the surface of the fire grate, thereby allowing a fire to be started.

Starting a fire in a domestic multi-fuel stove involves a series of operations. The first step is to lay a bed of kindling material, such as paper or wood, on the fire grate.

Fire-lighters may also be used. Pieces of solid fuel, such as coal or larger pieces of wood than those used for the kindling material, are then arranged on top of the bed of kindling. The bed of kindling is then lit and, once the solid fuel catches alight, further pieces of solid fuel are placed on to the fire.

This method of establishing and maintaining a fire in a domestic multi-fuel stove presents the problem of maintaining the positon of the solid fuel on top of the kindling before the fuel is lit, and maintaining the position of the fuel once the fire has been lit.

Solid fuel may fall away from the kindling during arrangement of the fuel. This may result in the solid fuel that falls away from the kindling not becoming lit after the kindling has been lit, thereby wasting fuel. In addition, if a surplus of solid fuel is placed on top of the kindling, some of the fuel may be located too far from the kindling to become lit, again resulting in the fuel being wasted. Some of the fuel may also become compacted, and so impede the flow of oxygen through the fire grate, which may result in less efficient or shorter lasting combustion once the fire is lit.

Once the fire has been lit, the arrangement of fuel is liable to collapse. This may result in lit fuel falling far enough away from the fire to cause the fuel to burn out.

Known devices which seek to retain kindling and fuel in place for the lighting of a fire may impede a flow of oxygen to the kindling and fuel, thereby reducing the efficiency of combustion and reducing the length of time that the fuel can burn for.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a device for retaining solid fuel on a fire grate. The device comprises a fuel retaining cage comprising a plurality of through-holes. The cage defines a hollow interior. A first end of the cage is substantially open, and a second end of the cage opposite the first end is substantially open.

The cage of the device retains fuel within the hollow interior during the initial lighting of the fuel, and during combustion of the fuel. The through-holes of the cage advantageously permit air (and particularly oxygen) to flow into the hollow interior of the device so that fuel placed within the device may burn efficiently. An additional advantage provided by the through-holes is that light and heat from a fire burning within the hollow interior passes unimpeded through the through-holes, thereby retaining the attractive quality of an open fire and ensuring that heat transfer from the fire to the exterior of the device is maximised.

The substantially open first and second ends of the cage ensure that a sufficient flow of oxygen reaches the solid fuel in use.

The first end may be configured to be supported by the fire grate. In this manner, an additional advantage of the open first end is that apertures of the fire grate remain unobstructed, so that burnt fuel can fall through the apertures and in to a soot tray, or similar, arranged beneath the fire grate. An additional advantage of the open second end is that uncombusted solid fuel can be easily placed inside the hollow interior prior to the lighting of a fire and during burning of a fire.

The plurality of through holes may define an open mesh.

The plurality of through-holes may extend over at least 90% of a surface area of the cage. This advantageously minimises obstruction of the flow of oxygen in to the hollow interior, while retaining the structural integrity of the cage.

Each of the plurality of through-holes may have a first maximum direction measured in a first direction and a second maximum dimension measured in a second direction. The second maximum dimension may be greater than the first maximum dimension. The first maximum dimension may be less than or equal to 30mm. This helps to ensure that when the device is used with solid fuel, such as coal, the fuel is retained within the cage due to the smaller of the two maximum dimensions, whilst the larger of the two maximum dimensions ensures that oxygen is able to flow freely in to the hollow interior of the cage.

The cage may be substantially tubular, and may define an unobstructed internal volume. This means that the entire volume of the hollow interior can be utilised when arranging fuel within the cage.

A cross-section of the cage may comprise a circle or an oval. An advantage of this is that that the cage does not comprise any corners within which fuel may become trapped and prevented from falling through the internal volume.

The cage may define a longitudinal axis, and the cage may taper inwardly towards the longitudinal axis from the first end in a direction towards the second end. This enables multiple devices to be stacked on top of each other for storage purposes, and helps combusted fuel to fall freely through the hollow interior of the cage in use.

Features which are described in the context of separate aspects and/or embodiments of the invention may be used together and/or be interchangeable wherever possible.

Similarly, where features are, for brevity, described in the context of a single embodiment those features may also be provided separately or in any suitable sub-combination. Features described in connection with the apparatus may have corresponding features definable and/or combinable with respect to a method or vice versa, and these embodiments are specifically envisaged.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings: Figure 1 shows a device for retaining solid fuel on a fire grate; Figure 2 shows an alternative view of the device of Figure I; Figure 3 shows another device for retaining solid fuel on a fire grate; Figure 4 shows an alternative view of the device of Figure 3; and Figure 5 shows a schematic representation of a device for retaining solid fuel arranged on a fire grate

DETAILED DESCRIPTION

Figure 1 shows a schematic representation of a device 10 for retaining solid fuel, such as coal or wood, on a fire grate. The device 10 comprises a fuel-retaining cage 2. The cage 2 defines a hollow interior into which, in use, fuel may be placed by a user such that the cage 2 retains the fuel inside the device 10.

A cross-section of the cage 2 is, in the example of Figure 1, substantially circular, though it will be appreciated that in other examples, the cross section of the cage 2 may define a different shape, such as a polygon or oval. In some examples, the cross-section of the cage 2 defines a regular shape. In other examples, the cross-section of the cage 2 defines an irregular shape.

The one or more walls of the cage 2 comprise a plurality of through-holes 3. The plurality of through-holes 3 permit air (and particularly oxygen) to flow into the hollow interior of the device 10 so that fuel placed within the device 10 may burn efficiently. The through-holes 3 also permit a user of the stove to see a fire burning within the device 10 when it is in use. The through-holes 3 are not so large as to permit fuel to fall out from within the interior of the cage 2 when the device 10 is in use.

In the example shown in Figure 1 the through-holes 3 extend over at least 90% of the surface area of a shape that is defined by the wall(s) of the cage 2. In other example devices the through-holes 3 may make up at least 95% of the surface area of the cage 2. Put another way, the through-holes 3 are defined by bars 8 of the cage. The bars 8 make up 10% or less of the surface area of the cage, for examine 5-10%.

The cage 2 shown in Figure I has two ends, a first end 4 and a second end 5 that is opposite the first end 4. The first end 4 of the cage 2 is substantially open, and the second end 5 of the cage 2 is also substantially open. in the example shown both ends of the cage are entirely open, meaning that the end apertures are free from obstructions, such as cross-members.

The first end 4 the device 10 has a footprint that is sized to fit within a domestic fire grate. The first end 4 is also shaped so that it may be supported by a fire grate in use.

In the present example, the first end 4 of the cage 2 defines a plane, such that the cage 2 may be placed on a fire grate in a stable manner when in use. Fuel may then be placed into the interior of the device 10 through the substantially open second end 5.

The cage 2 that is shown in Figure 1 has a substantially unobstructed internal volume, such that the interior of the cage 2 may easily be stacked with fuel when the device is in use.

The cage 2 defines a longitudinal axis 6 extending between the first and second ends 4, 5 and through a centre of the cage 2. The cage 2 has a first diameter 7a at the first end 4. The cage 2 also has a second diameter 7b at the second end 5, which in this example is smaller than the diameter 7a at the first end, such that the tubular wall of the cage 2 tapers from the first (lower) end towards the second (upper) end with respect to the longitudinal axis 6.

As noted above the purpose of the cage 2 is to retain fuel within the interior of the device 10, such that the fuel burns efficiently inside the cage 2. To this end the through-holes 3 are sized such that fuel cannot easily fall out when the device 10 is in use. Each of the plurality of through-holes 3 has a first maximum dimension 9a and a second maximum dimension 9b measured in a different direction to the first maximum dimension. The size of at least the first dimension is selected such that fuel is retained within the interior of the device 10.

In the example shown in Figure 1 the first dimension 9a is substantially equal to the second dimension 9b, such that the through-holes are substantially square. in particular, the through-holes 3 have a maximum dimension 9a as measured perpendicularly to the longitudinal axis 6 of approximately 30mm, and a maximum dimension 9b as measured in parallel with the longitudinal axis 6 is also approximately 30mm.

It will be appreciated that in other examples the second maximum dimension might be greater than the first maximum dimension For instance, the through-holes 3 might have a first maximum dimension of 30mm or less, and a second maximum dimension of greater than 30mm. When the device 10 is used with solid fuel, such as coal, the fuel is retained within the cage 2 due to the smaller of the two maximum dimensions, whilst the larger of the two maximum dimensions helps ensures that oxygen is able to flow freely in to the hollow interior of the cage 2, In the example shown in Figure 1 the through-holes 3 are substantially regular in shape, but it will be appreciated that in other examples the through-holes 3 might be different in shape. It will be appreciated that the through-holes 3 might be of any shape that is desired, such as rectangular, circular, polygonal, etc. A first subset of the through-holes 3 might be one shape and/or size, whilst and a second subset of the through-holes 3 might be another shape and/or size.

The device 10 has dimensions selected so that the device is sized to fit within a conventional fire grate. In some examples, the height of the device 10, measured between the first end 4 and the second 5, does not exceed 130mm, and might be in the range 100-130mm. In examples in which the cross-section of the device 10 is substantially circular, such as that shown in Figures 1 and 2, a maximum diameter of the device 10 does not exceed 190mm. The cross-section might be in the range 160- 190mm, for example. . The one or more walls 2 of the cage 10 are formed from a plurality of horizontal members 11 and a plurality of vertical members 12, with gaps between the horizontal and vertical members 11, 12 defining the through-holes 3. The one or more walls 2 may therefore comprise an open mesh. The horizontal members 11 extend continuously to define the cross-section of the cage 10. For example, the each horizontal member 11 may extend continuously in a circle to define a circular cross-section. Alternatively, multiple members may be joined together to provide the horizontal members 11 and define the cross-section of the cage 10. For example, four linear members may be joined together at the ends to form a single horizontal member defining a square cross-section In the example of Figures 1 and 2, the horizontal and vertical members I I. 12 are formed from a metal, such as steel, for example stainless steel wire. The thickness of the wire in this example is within the range of 3-4inm inclusive. In other examples, the thickness of the wire may differ, e.g. between 2-5mm so long as the structural integrity of the cage is maintained, and the oxygen flow to the fuel within the cage is not restricted.

As noted above, the cage 10 tapers inwardly from the first end 4 to the second end 5. In some examples, the difference between the maximum diameter 7a of the cage 2 at the first end 4 and the maximum diameter 7b of the cage 2 at the second end is within the range of 25-35mm. In the example shown in Figure 1, this difference is 30mm.

That is, the diameter 7a of the cross section of the lower end 4 is approximately 190mm, whilst the diameter 7b of the cross section of the upper end is approximately 160mm. This taper enables multiple devices 10 to be stacked on top of each other for storage purposes, as well as helping combusted fuel to fall freely through the hollow interior of the cage 2 and through a fire grate in use, as described below in reference to Figure 5.

Figure 2 shows a plan view of the device 10. Like reference numerals have been used to indicate the same components in Figures 1 and 2. The circular cross section defined by the horizontal members 11 can be clearly seen in Figure 2. Furthermore, it can be seen that there are no components obstructing the internal volume and/or the openings defined by the first and second ends 4, 5.

Figure 3 shows a schematic representation of an alternative device 20 for retaining solid fuel. The device 20 of Figure 3 has a number of components in common with the device 10 of Figures 1 and 2. Like reference numerals have been used to indicate like components.

The device 20 comprises a cage 2 formed from an open mesh of bars 8 defining through-holes 3 of the type discussed above in connection with Figures 1 and 2.

However, the device 20 differs from the device 10 of Figures 1 and 2 in that the cross-section of the cage 20 comprises an oval. Figure 4 shows a plan view of the device 20. Such a device may be useful in wider stoves.

Rather than each end 4, 5 of the device having a substantially constant diameter, each end has a maximum diameter 13 and a minimum diameter 14. The device 20 has dimensions selected so that the device is sized to fit within a conventional fire grate. For example, the height of the device 20, measured between the first end 4 and the second 5, may not exceed 130inm, and might be in the range 100-130mm. In the example shown in Figures 3 and 4, the maximum diameter 13 of the first end of the device 20 does not exceed 310mm (for example is in the range 190mm-310mm) and the minimum diameter 14 of the lower end does not exceed 190inm (for example in the range 160-190mm).

The device 20 shown in Figures 3 and 4 further differs from the device 10 shown in Figures 1 and 2, in that the walls of the cage 2 arc substantially parallel to the longitudinal axis 6 of the device. The cage 2 is thus substantially straight sided, without the taper shown in Figure 1. The dimensions of the second end 5 are thus substantially the same as the dimensions of the first cud. It will be appreciated however that the cage could taper towards the second end if required.

Figure 5 shows a schematic representation of a device 50 in situ on a fire grate 13. The device 50 could be any one of the devices 10 or 20 that are discussed above (or indeed any alternative device falling within the scope of the claims) The through-holes 3 have been omitted from Figure 5 for clarity.

In use, the device 50 is positioned on a fire grate 13 such that the first end 4 is supported by an upper surface of the fire grate 13. Kindling material is then placed within the cage 50 and on the upper surface of the fire grate 13 (which is accessible through the open first end 4 of the cage 50). The kindling material may cover substantially the entire area of the upper surface of the fire grate 13 that is enclosed by the cage 50. Solid fuel, such as coal or wood, is then placed on top of the kindling. The solid fuel is retained by the one or more walls 2 of the cage 50. The kindling is then lit and, once the initial arrangement of solid fuel catches fire, additional solid fuel is placed within the cage 50 The substantially open first end 4 ensures that a sufficient flow of oxygen reaches the kindling and fuel through the fire grate. The substantially open first end 4 also ensures that apertures of the fire grate remain unobstructed, so that burnt fuel can fall through the apertures of the grating and in to a soot tray, or similar, arranged beneath the fire grating.

The at least one wall 2 of the cage 50 ensures that the fuel is maintained in a vertical stack formation when burning, thereby enabling the fire to burn effectively and efficiently. The substantially open second end 5 enables solid fuel to be easily loaded in to the cage 50. As the fire burns fuel at the first end 4 of the device, unburnt fuel is automatically fed down towards the fire under the action of gravity.

The through-holes 3 not only ensure that a flow of oxygen to the fire is not impeded, they also allow the amount of unburnt fuel within the cage 50 to be monitored. Fuel with the cage 50 can therefore be replenished as required. Light from the fire passes unimpeded through the through-holes 3, retaining the attractive quality of an open fire. Heat also passes easily through the through-holes 3, and is radiated out from the material forming the one or more walls of the cage 50.

The cage 50 may be constructed from a heat resistant metal, such as a high grade stainless steel with a thick gauge for optimum life.

Although the devices shown in the Figures define generally rounded or oval cross sections, it will be appreciated that a device could be constructed having any desired cross section, which may be regular or irregular and may be constant or varying along the longitudinal axis of the device.

Similarly, the through-holes 3 might have dimensions that differ from those discussed above, depending on the type of fuel that is intended to be used with the device. For coal, for example, at least the first maximum dimension 9a might be 30inm or less, for example 20-30mm, or 25-30mm.

Rather than being formed from a single continuous wall of material, the device may be formed from a plurality of joined walls. This may be appropriate where the device has a polygonal cross section, such as a square, pentagon, hexagon, octagon, etc. It will be appreciated that features which are described in the context of separate devices may be provided in combination in a single device if required. Conversely, various features which are, for brevity, described in the context of a single device, may also be provided separately or in any suitable sub-combination. The applicant hereby gives notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom. Features of the apparatus described may be incorporated into/used in a corresponding method and vice versa.

Claims

CLAIMS1. A device for retaining solid fuel on a fire grate, comprising a fuel retaining cage, wherein the cage comprises a plurality of through-holes and defines a hollow interior, wherein a first end of the cage is substantially open, and a second end of the cage opposite the first end is substantially open.
2. The device of claim 1, wherein the second end of the cage is substantially open
3. The device of any preceding claim wherein the first end is configured to be supported by the fire grate.
4. The device of any preceding claim, wherein the plurality of through holes define an open mesh.
The device of claim 4, wherein the mesh is defined by wire bars, wherein the wire bars make up 10% or less of the surface area of the cage.
6. The device of any preceding claim, wherein the plurality of through-holes extend over at least 90% of a surface area of the cage.
7. The device of any preceding claim, wherein each of the plurality of through-holes has a first maximum direction measured in a first direction and a second maximum dimension measured in a second direction, wherein the second maximum dimension is greater than or equal to the first maximum dimension.
8. The device of claim 7, wherein the first maximum dimension is less than or equal to 30mm.
The device of any preceding claim, wherein the cage is substantially tubular.
10. The device of any preceding claim, wherein the cage defines an unobstructed internal volume.
11. The device of any preceding claim, wherein a cross-section of the cage comprises a circle or an oval.
12, The device of any preceding claim, wherein the cage defines a longitudinal axis, and the cage tapers inwardly towards the longitudinal axis from the first end in a direction towards the second end.