WO2010040155A2

WO2010040155A2 - Combustion device

Info

Publication number: WO2010040155A2
Application number: PCT/ZA2009/000086
Authority: WO
Inventors: Tasos Calantzis; Frederick Zacharias Kruger
Original assignee: Calantzis Design (Pty) Ltd
Priority date: 2008-09-30
Filing date: 2009-09-30
Publication date: 2010-04-08
Also published as: ZA201102015B; WO2010040155A3

Abstract

The invention relates to a combustion device for combusting a liquid fuel, comprising a fuel reservoir, a combustion chamber, at least one wick holder for holding a wick, an extinguisher cooperating with the or each wick holder, the extinguisher being displaceable between a flame supporting position and a flame extinguishing position; a displacement means arranged to displace the or each extinguisher between said flame supporting position and said flame extinguishing position; and an activator for said displacement means; in which said displacement means comprises a toothed pinion gear operatively connected with a toothed rack connected to said extinguisher; a stopping device moveable between a gear engaging position in which said stopping device engages said gear and a disengaged position in which said stopping device is disengaged from said gear; and biasing means arranged to bias said rack such that said extinguisher moves from said flame supporting position to said flame extinguishing position when said stopping device moves from the gear engaging position to the disengaged position; and where the activator is arranged to move the stopping device from the gear engaging position to the disengaged position when said activator is activated. In a further embodiment, said extinguisher is a snuff tube located around the or each wick holder, the snuff tube being slidably movable between the flame supporting position in which an upper portion of a wick held in the wick holder is exposed above the upper end of the snuff tube, and the flame extinguishing position in which the upper portion of a wick held in the wick holder is covered by the snuff tube, and wherein the combustion device further comprises a further tube located around the snuff tube and wick holder, the further tube being arranged to cover a bottom portion of the snuff tube when the snuff tube is in the flame extinguishing position to impede the flow of air from the exterior to the interior of the snuff tube around the bottom end of the snuff tube.

Description

COMBUSTION DEVICE

Field of the Invention

This invention relates to a combustion device, specifically, to combustion device for combusting a liquid fuel which is of the wick-fed type.

Background of the Invention

In many parts of the world, portable devices for burning liquid fuel are used to provide heat and light. For example, paraffin stoves are widely used for cooking. One type of oil- burning device, known as the wick-fed type, comprises a reservoir for the fuel and a wick or wicks which is located with one end in contact with the fuel and the other in a combustion chamber. Fuel is transferred by capillary action from the fuel reservoir and is burnt in the combustion chamber.

If knocked over, such an oil-burning device can pose a serious fire hazard. A number of proposals have been made to provide safety features which attempt to stop the flow of fuel from the reservoir if the device is knocked over. For example GB 1 195 918 describes an arrangement whereby a safety mechanism comprises a flame extinguishing member, a foot, and a rod extending between the flame extinguishing member and the foot. The foot is urged into contact with the ground by a spring in compression when the device is in the normal operating position. If the device is knocked over, the spring urges the rod in a downward direction, which activates the flame extinguishing member. GB 1 390 763 describes a device with a similar objective, also utilising a sprung foot.

WO 2007/08041 describes an improved device in which the fuel tank of a wick-fed device is supported on a frame such that the lower end of a rod contacts the floor, urged thereto by a spring. Flame extinguishing means comprise wick extinguisher tubes capable of smothering a flame. A rack and pinion arrangement is provided which serves two purposes. First, it allows a user to raise or lower said tubes manually. Secondly, if the device is removed from the floor, the rack and pinion operate under action of the spring to activate the wick extinguisher tubes. However, the device of WO 2007/08041 has a number of disadvantages. The various parts of the device are interconnected such that it is necessary to activate the safety mechanism if a user wishes to snuff the flame and turn the device off. Specifically, handle 190 is directly linked to pinion 188.1 , which in turn engages the teeth of 182.1 , 182.2, 186.1 and 186.2. When the handle is turned, it turns pinion 188.1 which moves racks 182.1 and 182.2 upwards, and moves racks 186.1 and 186.2 downwards. Racks 186.1 and 185.2 are linked to the actuator rod which is spring-loaded under compression when the device is standing on a relatively flat surface. This means that when the handle is turned, the actuator rod moves downwards with the result that the device is lifted off the table. Further, the snuffing mechanism comprises a single snuff tube array that requires a very small tolerance between snuff tubes and wick holders. The small tolerance requires precisely made parts and assembly to function properly, which is achievable but at a cost.

We have now designed a new safety mechanism which combines a flame regulation mechanism and a safety device to provide a simpler and more controllable system, with fewer working parts providing a cost effective device in which the flame can be snuffed very rapidly.

Brief Description of the Invention

Accordingly, the present invention provides a combustion device for combusting a liquid fuel, comprising:

a reservoir for said fuel;

a combustion chamber for burning said fuel;

at least one wick holder for holding a wick in a position such that when the device is in use a lower end of said wick is in contact with said fuel and an upper end of said wick is located within said combustion chamber;

an extinguisher cooperating with the or each wick holder, the extinguisher being displaceable between a flame supporting position in which a wick held in the wick holder can support a flame and a flame extinguishing position in which a wick held in the wick holder cannot support a flame;

a displacement means arranged to displace the or each extinguisher between said flame supporting position and said flame extinguishing position; and

an activator for said displacement means;

characterised in that said displacement means comprises a toothed pinion gear operatively connected with a toothed rack connected to said extinguisher; a stopping device moveable between a gear engaging position in which said stopping device engages said gear and a disengaged position in which said stopping device is disengaged from said gear; and biasing means arranged to bias said rack such that said extinguisher moves from said flame supporting position to said flame extinguishing position when said stopping device moves from the gear engaging position to the disengaged position; and where the activator is arranged to move the stopping device from the gear engaging position to the disengaged position when said activator is activated.

Generally, the device of the invention will be configured such that the default position of the device has the extinguisher in its flame extinguishing position. This position may be achieved by user operation; by automatic operation of the activator for the displacement means when the device is tilted or knocked over; and optionally by operation of a mechanism automatically triggered when the fuel reservoir is opened to allow fuel to be added or removed.

The device of the invention may be used for combustion of any suitable liquid fuel, for example oil, paraffin, kerosene and fuels comprising material derived from biomass (sometimes referred to as biofuel). The device may be used for cooking, heating or lighting. Preferably, the device is a paraffin, kerosene or biofuel stove.

^• The device of the invention may comprise a single wick holder for holding a single wick, or a plurality of wick holders for holding a plurality of wicks. When the device is a stove, a single wick may be annular, but preferably a plurality of separate wicks is used. The extinguisher preferably comprises a snuff tube cooperating with each wick holder such that in the flame supporting position the snuff tube overlaps the wick holder to a significant extent, exposing the upper portion of the wick. In this position air is drawn directly into the combustion chamber through holes in the combustion chamber to reach the upper end of the wick so that a flame is capable of burning. As the snuff tube is gradually raised so that a greater portion of its length extends beyond the upper end of the wick holder, less of the wick is exposed, the supply of air to the upper portion of the wick is restricted, and a smaller flame results. Ultimately, at its flame extinguishing position, the snuff tube extends to sufficiently beyond the upper end of the wick holder that insufficient air reaches the upper portion of the wick to support a flame.

In a preferred embodiment, the extinguisher comprises snuff tubes which are connected to the combustion chamber in such a way that operation of the displacement means causes not only the snuff tubes comprising the extinguisher but also the whole of the combustion chamber to move between a flame extinguishing position and a flame supporting position. This embodiment gives excellent flame control.

In a preferred embodiment of this type, the toothed pinion gear may be turned by means of a regulator knob. When the combustion chamber and the snuff tubes move downwards, the amount of air available to the wicks increases, and hence the flame may be regulated. When the combustion chamber and the snuff tubes move upwards, the amount of air available to the wicks decreases, ultimately extinguishing the flame(s). Downward movement compresses biasing means, preferably in the form of wick springs located between a plate on which the snuff tubes are mounted and a fixed plate (which may also act as a heat shield between the combustion chamber and the fuel reservoir). This indirectly exerts a force on the gear. The force urges the gear to turn in the opposite direction and push the combustion chamber upwards into the default (flame extinguishing) position.

The stopping device is displaceable between a position in which it engages with the gear, and a position in which it is disengaged from the gear. Suitably, the stopping device is located within a safety guide located generally axially in the centre of the device of the invention, and is connected to a foot which in unconstrained position extends out below the lower surface of the device, and which forms the activator. Biasing means, for example a helical spring, is located between the foot and a fixed plate on the stopping device. When the device of the invention is placed on a relatively flat surface, for example on a table top, this spring is compressed, and pushes the stopping device upwards, and urges the foot downwards. The stopping device is pushed upwards against the gear teeth. This prevents the gear from turning despite the tension caused by the wick springs. If the stopping device is not engaged with the gear, the gear is free to turn and thus allows the combustion chamber to move upwards into the default position under the operation of the wick springs.

According to an alternative embodiment, the stopping device is connected to the reservoir, the reservoir acting as the activator, and in which the reservoir is axially movable relative to an outer housing shell between a primary position, wherein the reservoir and the outer housing shell move away from one another thereby urging the stopping device into its gear disengaged position, and a secondary position, wherein the reservoir and the outer housing shell move toward one another thereby urging the stopping device into its gear engaging position. The reservoir and the outer housing shell may be positionable in the secondary position by placing the device on a relatively flat surface. Generally, the reservoir and outer housing shell are biased toward the primary position. Typically, the outer housing shell houses at least some of the components making up the device. The purpose of the alternative embodiment is to further reduce the number of working parts and manufacturing costs of the device by eliminating the need for a foot and the safety guide located generally axially in the centre of the device

When the stopping device is pushed against the gear, the indirect force applied by the stopping device spring onto the gear is greater than the force applied by the wick springs onto the gear, thus preventing the gear from turning. If the regulator knob is turned by the user it increases the force that is trying to turn the gear, until that force is greater than the force applied by the stopping device spring. The profile of the stopping device that engages the gear is designed in such a way that it allows the gear to push the stopping device plate downwards when the regulator knob is turned. The consistent force applied by the stopping device spring when the device of the invention is placed on a relatively flat surface, for example on a table top, keeps the stopping device pushed upwards against the gear and keeps the gear from turning.

When the gear turns it pushes the combustion chamber upwards or downwards, depending on the direction of rotation. The above explains the adjustment of the flame by the user, and the safety mechanism operating automatically in the event that the device is tilted or knocked over. Preferably means are also provided such that fuel may only be added to the reservoir when the extinguisher is in the flame extinguishing position. Thus, in a preferred embodiment, the safety mechanism is operatively connected with the fuel cap provided in the fuel reservoir, which may be opened to allow fuel to be added or removed. In this embodiment, a lever must be operated before the fuel cap can be removed. This lever is connected to means adapted to operate on the stopping device, such that when the lever is operated, the stopping device is urged into the position in which it is disengaged from the gear.

The device of the present invention gives proper and reliable snuffing, and has better flame control than prior art devices because of the incorporation of the stopping device. Due to the stopping device, the combustion chamber clicks into a plurality of discrete positions, giving safe and reliable control. Fewer moving parts means that the device of the invention is very cost effective.

WO 2007/080471 uses extinguishing tubes slideably located over wick holders to extinguish flames. A disadvantage of this device is that when the snuff tubes are operated, air is still able to reach the upper portion of the wick by passing under the lower end of the snuff tube. We have found that control over flames can be further improved by, instead of using one extinguishing tube for each wick holder, a double tube arrangement is used. In this arrangement, a snuff tube is located around each wick holder, the snuff tube being slidably movable between the flame supporting position in which an upper portion of a wick held in the wick holder is exposed above the upper end of the snuff tube, and the flame extinguishing position in which the upper portion of a wick held in the wick holder is covered by the snuff tube. A further tube is located around the snuff tube and wick holder, the further tube being arranged to cover a bottom portion of the snuff tube when the snuff tube is in the flame extinguishing position to impede the flow of air from the exterior to the interior of the snuff tube around the bottom end of the snuff tube. In normal operation of the device, the arrangement is such that only air that reaches the wick from the top of the device, i.e. inside the combustion chamber, is sufficient to sustain combustion.

When each snuff tube is moved upwards, the amount of air that can reach the wick from inside the combustion chamber is gradually reduced until there is not enough air to sustain combustion. Without the presence of the further tube surrounding the wick holder, air would be able to reach the wick from the bottom, because of the short air path. The further tube creates an air flow path that is in the opposite direction from the normal flow of hot air (the air around the tubes is hot because of the combustion that is taking place inside the device). The hot air first has to travel downwards between the further tube and the snuff tube, which slows it down sufficiently to reduce the amount of air that can reach the wicks to a point where combustion is no longer possible.

Accordingly, the present invention also provides a combustion device for combusting a liquid fuel, comprising:

a reservoir for said fuel;

a combustion chamber for burning said fuel;

an activator for said displacement means;

characterised in that said extinguisher is a snuff tube located around the or each wick holder, the snuff tube being slidably movable between the flame supporting position in which an upper portion of a wick held in the wick holder is exposed above the upper end of the snuff tube, and the flame extinguishing position in which the upper portion of a wick held in the wick holder is covered by the snuff tube, and wherein the combustion device further comprises a further tube located around the snuff tube and wick holder, the further tube being arranged to cover a bottom portion of the snuff tube when the snuff tube is in the flame extinguishing position to impede the flow of air from the exterior to the interior of the snuff tube around the bottom end of the snuff tube.

The wick holders, snuff tube and further tube are preferably of circular cross-section, but other cross-sections are of course possible.

Brief Description of the Drawings

The invention is further illustrated in the accompanying drawings, in which:

Figure 1 shows a perspective view of a liquid fuel-burning device according to the invention;

Figure 2 shows a perspective view of the fuel reservoir of the device of Figure 1 , together with the fuel cap and combustion regulating controls;

Figure 3 shows a cross-sectional side elevation of the device of Figure 1 in an intermediate configuration;

Figure 4 shows a cross-sectional side elevation of the device of Figure 1 in its operative state, placed on a relatively flat surface;

Figure 5 shows a cross-sectional side elevation of the device of Figure 1 in the safety configuration after the safety mechanism has been triggered following the device being knocked over or tilted from the vertical;

Figure 6 shows a cross-sectional side elevation of the device of Figure 1 in the safety configuration adopted when the fuel cap of the fuel reservoir is opened; and

Figure 7 shows the detail of the wick post and snuff post of the device of Figure 1 indicated generally at X of Figure 3. Detailed Description of the Invention

A device for combusting liquid fuel according to the invention is shown in Figures 1 to 7. An outer shell 10 is provided with an internal pre-heat shield 7. An annular cover 5 surmounts shell 10 and pre-heat shield 7, and supports 6 for a cooking pot or similar are mounted on cover 5. A liquid fuel reservoir 50 of generally toroidal configuration comprises a base 33 having sides 34 and 35 defining a cylindrical passage 49. Reservoir fuel cap base 36 defines an orifice for adding liquid fuel to the reservoir, and fuel cap base 36 is closed by fuel cap 8.

Regulator knob base 16 provides an orifice in outer shell 10 through which regulator knob 15 protrudes. Internal to shell 10, regulator knob 15 is connected to one end of rod 25. Rod 25 passes through toothed pinion gear 26, and the remote portion 25(a) of rod 25 is flattened to prevent lateral movement of gear 26. Rod bracket 24 is secured to the upper surface of side 35 and secures the remote end of rod 25. Safety pin plates 23 and 31 are secured to rod bracket 24 located on an upper surface of side 35 and secure stopping device 20 and assist in the alignment of safety guide 21.

Fuel cap 8 is provided with a safety lever handle 28 which in turn operates safety lever 27, which is pivotally connected to safety pin plates 31 and 23 located on an upper surface of side 35. When fuel cap 8 is closed, the end 27(a) of safety lever 27 remote from fuel cap 8 lies a short distance above a nose 48 of stopping device 20.

A plurality of tubular wick holders 38 are located at the upper surface of side 35 of the fuel reservoir 50, providing communication with the interior of the fuel reservoir. In use, a corresponding number of wicks 39 are located in and extend through wick holders 38 into the fuel in the reservoir. Each wick 39 is a close fit for the corresponding wick holder 38 which prevents fuel from leaking. Each wick holder 38 is surrounded by a helical spring

42 terminating at a fixed plate 40 which also acts as a heat shield. A corresponding number of tubular snuff tubes 12 having a diameter a little larger than wick holders 38 are mounted on snuff plate 11. A corresponding number of further tubes 41 having a diameter a little larger than snuff tubes 12 are connected to the lower end of wick holders

38 and to snuff tubes 12. The snuff tubes 12 are vertically moveable between wick holders 38 and further tubes 41. An annular combustion chamber 52 formed of inner cylinder 1 , outer cylinder 3 and outer cylinder mantle 4 is mounted on snuff plate 11 above snuff posts 12.

A toothed rack 13 is secured at its upper end to snuff plate 11. Toothed pinion gear 26 engages with toothed rack 13.

A split pin 29 that extends through safety pin plate 23, safety guide 21 and safety pin plate 31 secures stopping device 20. The lower end of stopping device 20 is connected to safety foot 17 which has an upwardly extending cylindrical portion 46. A helical spring 18 is located between plate 19 and foot 17, surrounding cylindrical portion 46. Safety guide 21 locates and generally surrounds rack 13 and stopping device 20. The head 47 of stopping device 20 is capable of engaging with gear 26.

In an alternative embodiment (not shown), and for the purposes of reducing the number of working parts and manufacturing cost even further, the stopping device 20 acts between the outer shell 10 and the reservoir 50, thereby eliminating the need for the safety foot 17 and the cylindrical passage 49 defined in the reservoir 50. In this embodiment, with the outer shell 10 axially movable relative to the reservoir 50, the lower end of stopping device

20 is connected to the reservoir 50. Further, the device may include a means for biasing the outer shell 10 and the reservoir 50 away from one another.

Referring now back to the illustrated embodiment, and in normal operation when placed on a surface, the combustion chamber 52 may travel between two extreme positions, a lower operative position shown in Figure 4, and a higher non-operative position shown in Figures 5 and 6.

In Figure 4, the device is placed on a relatively flat surface, and the head 47 of stopping device 20 is engaged with gear 26. In this configuration the device is in an operative state, and can be turned on, turned off, and regulated. Combustion chamber 52 is in its lower, operative, position. In this position, the snuff tubes 12 surround the wick holders 38, air reaches the wicks 39 and a flame can be sustained in combustion chamber 52. In use, when the head 47 of stopping device 20 engages with gear 26, this provides resistance which overcomes the force of wick springs 42 which are acting to bias the rack 13 to the flame extinguishing position. However, user operation of the regulator knob 15 overcomes the force of the wick springs 42 which thereby allows vertical upward and downward movement of the combustion chamber 52 from the position shown in figure 4. When regulating the combustion chamber upwards, less force is needed by the user because wick springs 42 aid the direction of movement (only force of spring 18 needs to be overcome). When the combustion chamber is moved downward by knob 15, (increase power/flame) more force is required because springs 42 are applying force that is in the opposite direction to the movement. Operation of rod 25 by user rotation of regulator knob 15, causes rotation of gear 26 which, being engaged with toothed rack 13, causes upwards motion of snuff plate 11, snuff tubes 12 and combustion chamber 52. The relative displacement of snuff tubes 12 and wick holders 38 regulates the amount of air available at the upper ends of wicks 39 and hence, in use, regulates the flame. As the upwards vertical displacement increases, the amount of air available reduces to the point at which the flame is extinguished. Operating the regulator knob 15 in the opposite direction allows vertical downward movement back to the position shown in Figure 4.

The configuration of the device following operation of the safety device which operates when the device is lifted or tilted is shown in Figure 5. The device is in an inoperative state. Here, foot 17 has been removed from contact with the surface on which it was standing. Accordingly the compression of spring 18 has been released, and spring 18 urges stopping device 20 downward and foot 17 outward beyond the bottom of the device. This movement of stopping device 20 causes disengagement of the head 47 of stopping device 20 with gear 26. Wick springs 42 act on snuff plate 11, forcing snuff tubes 12 and combustion chamber 52 into the upper position where no flame can be sustained. In order to return the device to an operable position, a user needs to stand the device on a surface. This compresses safety spring 18, stopping device head 47 engages with gear 26, and the user can then operate regulator knob 15 to return the combustion chamber to the lower, operative position of Figure 4.

Alternatively, and in accordance with the aforementioned alternative embodiment, removal of the device from contact with the surface on which it was standing causes the reservoir 50 to move axially away from the outer shell 10. Movement of the reservoir 50, having the lower end of the stopping device 20 connected thereto, urges the stopping device 20 thereby disengaging the head 47 of the stopping device 20 with gear 26. In turn, wick springs 42 act on snuff plate 11 , forcing snuff tubes 12 and combustion chamber 52 into the upper position where no flame can be sustained. In order to return the device to an operable position, a user needs to stand the device on a surface. This returns the outer shell 10 and the reservoir 50 into close proximity such that stopping device head 47 engages with gear 26 so as to allow the user to operate the regulator knob 15 to return the combustion chamber to the lower, operative position.

Referring now back to the illustrated embodiment, Figure 6 shows the safety configuration adopted by the device when the fuel cap 8 of the reservoir 50 is opened. In order to open the fuel cap while the device is standing on a surface and safety spring 18 is accordingly partially compressed, a user has to raise safety lever 28 which in turn forces end 27(a) of safety lever 27 down to bear onto the nose 48 of stopping device 20. This causes downward movement of stopping device 20 with additional compression of spring 18. Head 47 of stopping device 20 disengages from gear 26. Wick springs 42 act on snuff plate 11 , forcing snuff tubes 12 and combustion chamber 52 into the upper position where no flame can be sustained. Fuel cap 8 can be removed, and fuel added. Returning safety lever 28 to the normal position releases nose 48 of stopping device 20, head 47 of stopping device 20 engages with gear 26, and user operation of regulator knob 15 can then return the combustion chamber 52 to the operative position of Figure 4.

The large arrow 60 in Figure 7 shows the constricted air flow through a further tube 41 , a snuff tube 12 and a wick holder 38 when the combustion chamber 52 is in the non- operative position of Figures 5 and 6. The wick further tube 41 forces air to first travel downwards, which is in the opposite direction to the natural draft of hot air entering device 50 in normal use, instead of travelling directly upwards between the snuff tube 12 and wick holder 38. This ensures that when the combustion chamber 52 moves into an inoperative position, the flame is snuffed properly and reliably every time combustion chamber 52 moves into an inoperative position.

Although the invention has been described above with reference to a preferred embodiment, it will be appreciated that many modifications or variations of the invention are possible without departing from the spirit or scope of the invention.

Claims

1. A combustion device for combusting a liquid fuel, comprising:

a reservoir for said fuel;

a combustion chamber for burning said fuel;

an activator for said displacement means;

2. A device as claimed in claim 1, in which the stopping device is connected to the activator which comprises a foot which in unconstrained position extends out below the lower surface of the device, and which is biased such that when the device is placed on a relatively flat surface, the stopping device is urged into its gear engaging position.

3. A device as claimed in claim 1 , in which the stopping device is connected to the reservoir, the reservoir acting as the activator, and in which the reservoir is axially movable relative to an outer housing shell between a primary position, wherein the reservoir and outer housing shell move away from one another thereby urging the stopping device into its gear disengaged position, and a secondary position, wherein reservoir and outer housing shell move toward one another thereby urging the stopping device into its gear engaging position.

4. A device as claimed in claim 3, in which the reservoir and outer housing shell are positionable in the secondary position by placing the device on a relatively flat surface.

5. A device as claimed in claim 3 or claim 4, in which the reservoir and outer housing shell are biased toward the primary position.

6. A device as claimed in claim 3, claim 4 or claim 5, in which the outer housing shell houses at least some of the components making up the device.

7. A device as claimed in claim 1 , in which the extinguisher comprises a slidable snuff tube cooperating with the or each wick holder such that in the flame supporting position the snuff tube overlaps the wick holder to an extent sufficient to expose the upper end of a wick held in the wick holder, and in its flame extinguishing position the snuff tube permits supply of insufficient air to support a flame to the upper end of a wick held in the wick holder.

8. A device as claimed in claim 7, in which the or each snuff tube is connected to the combustion chamber in such a way that operation of the displacement means causes both the snuff tube and the combustion chamber to move between the flame extinguishing position and the flame supporting position.

9. A device as claimed in any one of the preceding claims, in which the biasing means arranged to bias said rack comprises springs connected to a fixed plate carrying the or each snuff tube.

10. A device as claimed in any one of the preceding claims, in which said extinguisher is a snuff tube located around the or each wick holder, the snuff tube being slidably movable between the flame supporting position in which an upper portion of a wick held in the wick holder is exposed above the upper end of the snuff tube, and the flame extinguishing position in which the upper portion of a wick held in the wick holder is covered by the snuff tube, and wherein the combustion device further comprises a further tube located around the snuff tube and wick holder, the further tube being arranged to cover a bottom portion of the snuff tube when the snuff tube is in the flame extinguishing position to impede the flow of air from the exterior to the interior of the snuff tube around the bottom end of the snuff tube.

11. A combustion device for combusting a liquid fuel, comprising:

a reservoir for said fuel;

a combustion chamber for burning said fuel;

an activator for said displacement means; characterised in that said extinguisher is a snuff tube located around the or each wick holder, the snuff tube being slidably movable between the flame supporting position in which an upper portion of a wick held in the wick holder is exposed above the upper end of the snuff tube, and the flame extinguishing position in which the upper portion of a wick held in the wick holder is covered by the snuff tube, and wherein the combustion device further comprises a further tube located around the snuff tube and wick holder, the further tube being arranged to cover a bottom portion of the snuff tube when the snuff tube is in the flame extinguishing position to impede the flow of air from the exterior to the interior of the snuff tube around the bottom end of the snuff tube.

12. A device as claimed in any one of the preceding claims, which comprises a plurality of wick holders.

13. A device as claimed in any one of the preceding claims, which is configured to have a default position in which the extinguisher is in its flame extinguishing position.

14. A device as claimed in any one of the preceding claims, in which a regulator knob is provided to permit a user to manually adjust the configuration of the device between the flame supporting position and the flame extinguishing position.

15. A device as claimed in any one of the preceding claims, in which means are provided such that fuel may only be added to the reservoir when the extinguisher is in the flame extinguishing position.

16. A device as claimed in claim 15, in which a fuel cap permitting fuel to be introduced to or removed from the reservoir is provided; a lever is provided which must be operated before removal of said fuel cap; and in which said lever is connected to means adapted to operate on the stopping device such that when said lever is operated, the stopping device is urged into a position in which it is disengaged from the toothed pinion gear.

17. A device as claimed in any one of the preceding claims, which is a paraffin, kerosene or biofuel stove.

18. A device substantially as herein described and illustrated.