WO2011108936A2

WO2011108936A2 - Transportable heating appliance comprising a fuel holder and a fuel supply

Info

Publication number: WO2011108936A2
Application number: PCT/NL2011/050158
Authority: WO
Inventors: Robert Christiaan Busschers
Original assignee: Niuw Innovatieve Concepten
Priority date: 2010-03-05
Filing date: 2011-03-07
Publication date: 2011-09-09
Also published as: NL2004349C2; WO2011108936A3

Abstract

The present invention relates to a portable heating appliance to be arranged on a support surface for providing combustion heat, the appliance comprising: - a support which is configured to be arranged on the support surface; - a burner unit which is to be detachably fastened to the support and comprises a combustion chamber for burning a mixture of air and liquid or gaseous fuel and a fuel supply for feeding fuel to the combustion chamber; wherein the support also forms a fuel holder for storing fuel and wherein, when fastened, the fuel holder at least partially surrounds the bottom circumferential part of the burner unit.

Description

TRANSPORTABLE HEATING APPLIANCE COMPRISING A FUEL HOLDER

AND A FUEL SUPPLY

The invention relates to a portable heating appliance to be arranged on a support surface for providing combustion heat.

Numerous portable appliances are known with which fuel can be burned for generating combustion heat. The most common solid fuel in areas without networks is biomass which is burned in or on the ground. This way of burning is used by about 3 billion people who in this way jeopardize their health owing to IAP (indoor air pollution). In addition, poor burning has an enormous impact on the environment as a result of the fact that local vegetation is disappearing and this is having a significant impact on the global climate. Now, the negative effects of the burning of biomass can be combated by using in this regard liquid fuels with associated clean burning. The remaining burners can be divided into various categories based on the sort of fuel that is used, each having their own advantages and drawbacks. Examples are burners which run on solid or liquid fuel which has to be attached in the burner before lighting and burners which make use of pressurized liquid fuel, gas burners and the like. Specifically, it is possible to distinguish, in addition to biomass, inter alia the following fuels which occur in areas without networks or other infrastructure: solar fuel, methanol/ethanol mixtures, gas and paraffin. Each of these fuels has one or more drawbacks. Solar energy can be stored only at relatively high costs. Third-generation bioethanol and biomethanol are promising, but are still in their infancy and are also highly flammable fuels. The transportation of gas requires a complex and costly infrastructure. Gas transportation stops where asphalt stops. Paraffin is often ubiquitous on account of the presence of aviation.

The combustion heat which is released during the burning of fuel can subsequently be used for various purposes, for example for preparing food (cooking appliance), heating a room (heating) or for generating a low capacity of electrical energy for charging electrical apparatuses such as mobile telephones and the like. Portable appliances of this type, which are also used for outdoor activities, are relatively light (mass typically 0.5-1.0 kg) and can usually be carried by a single person and be arranged on a support surface (usually the ground). These lightweight portable appliances are extremely suitable for use in (rucksack) camping, but numerous other uses are also possible.

A drawback of present-day burners, in which gas (for example a mixture of butane and propane) or petroleum or petrol is burned, is that the fuel is stored under high pressure in a tank, and that people are naturally afraid of pressurized appliances owing to the noise and the possible risk of leakage. In addition, gas is not available everywhere owing to the transport limitations and gas-filled cartridges cannot be filled by operators themselves, thus necessitating high-quality filling installations.

Furthermore, heating appliances have to draw in air which is necessary for the burning. A known drawback of known appliances is the fact that they draw in air which is polluted, for example with sand or dust; this can lead to damage in the appliance and/or to non-optimum burning. Heating appliances are for example known wherein the air required for the burning is supplied from the underside of the appliance, drawing on the chimney effect in this regard. However, if the apparatus is arranged on a dusty support surface, dust can be passed inward by the air flow at the underside of the appliance.

A second necessity for a burning process is the supply of fuel. This will require fuel to be locally available in the heating appliance. If too much fuel is available, hazardous situations can also occur; for example, the appliance can fall over, causing fuel to flow out of the appliance. Heating appliances with a wick, also referred to in the present document as wick heating appliances or wick burners for short, require, in particular, a local fuel reservoir into which the wick has to be dipped in order to absorb fuel for the burning.

A further drawback of some of the known heating appliances is the fact that they require a pump in order to feed fuel from the fuel reservoir to the combustion chamber. Pumps of this type can be electrically driven; tills requires an electric power source such as a storage battery. Hand-operated pumps are also possible, but require the user to have the discipline to pump every so often additional fuel to the fuel chamber.

It is known that not all the components of a heating appliance wear equally intensively. Both a vvick and seals have to be replaced after a certain time, but other parts may not require maintenance or replacement for a long time, for example. However, in many cases, it is necessary to replace the entire heating appliance or to disassemble the appliance when a critical component fails; this can lead to hazardous situations if the operator is not aware of the issues involved.

It is an object of the invention to provide an improved heating appliance in which one or more of the aforementioned drawbacks, and possibly other drawbacks, of the prior art are wholly or partially overcome.

It is a further object of the invention to provide a relatively safe and/or operationally reliable heating appliance.

It is a further object of the invention to provide a pressureless or at least low-pressure heating appliance in which a fuel pump may be dispensed with.

It is a further object of this invention to improve heating appliances with a wick.

According to a first aspect of the invention, at least one of the aforementioned objects is achieved in a heating appliance of the type mentioned in the preamble, the appliance comprising

- a support which is configured to be arranged on the support surface;

- a burner unit which is to be detachably fastened to the support and comprises a fuel reservoir for storing fuel, a combustion chamber for burning a mixture of air and liquid or gaseous fuel and a first fuel supply for feeding fuel from the fuel reservoir to the combustion chamber;

wherein the support also forms a detachable fuel holder for storing fuel, the appliance further comprising a second fuel supply for feeding fuel from the fuel holder to the fuel reservoir, wherein the fuel holder at least partially surrounds the bottom circumferential part of the burner unit, when the fuel holder is fastened to the fuel reservoir.

In certain embodiments, the fuel holder surrounds the burner unit over an angle of 90 degrees, 180 degrees or even over the full 360 degrees. The same may apply to the fuel reservoir. In certain embodiments, the fuel holder surrounds a center part of the burner unit (which center part may be used as an supply air for feeding air to the combustion chamber) or at least a part thereof, in case the appliance makes use of a wick to transport fuel from the fuel reservoir to the combustion chamber, the wick may be cylindrical and the wick is arranged with al least its lower end in a substantially annular fuel reservoir.

The fuel is stored in a fuel holder and a fuel reservoir, wherein the fuel holder can be detached from the burner unit and therefore from the fuel reservoir. The fuel reservoir and fuel holder may be embodied such that the amount of fuel in the foel reservoir is much smaller than the amount of fuel in the fuel holder, in fact, only an amount of fuel needs to be present in the fuel reservoir that is sufficient to provide for an adequate combustion in the combustion chamber. Since the amount of fuel in the fuel reservoir is small, the risk of fuel accidently entering the combustion chamber, for instance if the appliance is kept upside down or has fallen over, is reduced so that the safety of the appliance can be increased.

In an embodiment of the present invention the fuel holder is an exchangeable fuel holder, removably attached to the burner unit. If the appliance runs out of fuel, the empty fuel holder may be easily replaced by a full holder, for instance by removing the burner unit from the empty holder and placing the burner unit into another holder. IN embodiments of the invention the combustion may continue during replacement of an empty fuel holder with a loaded fuel holder. In certain embodiments, the fuel holder (support) surrounds the bottom circumferential part in question of the burner unit, for example the bottom half or the bottom quarter of the burner unit, in its entirety, that is to say over the full 360 degrees of the circumference of the burner unit. An example of an embodiment of this type is that in which the fuel holder is substantially annular or toroidal and the burner unit is to be attached in the central opening of the annular or toroidal shape. This can lead to a very stable arrangement of the burner unit in which the risk of falling over is extremely low.

In other embodiments, the fuel holder surrounds the burner unit merely over a part of the circumference (such as for example at least 90°). An example of an embodiment of this type is that in which the fuel holder (support) is "horseshoe"-shaped. In this embodiment, the shape can be selected in such a way that the fuel holder can be slid laterally along the burner unit, but other embodiments in which the fuel holder can be slid into the central opening from above or below are also possible.

However far the fuel holder (support) extends around the circumferential part in question of the burner unit, the fuel holder may or may not run continuously at the underside of the burner unit. However, in many embodiments, the fuel holder will surround the burner unit only in the lateral direction. This allows the height of the heating appliance to remain limited.

In one embodiment of the invention, the fuel holder is substantially annular or toroidal and is in addition embodied in such a way that the burner unit is slidable into the associated central opening. In this case, the fuel holder can be removed via the underside of the burner unit or, in certain embodiments, the fuel/air supply module, also referred to in the present document as the service module, of the burner unit. In other words, the underside of the burner unit can be slid into the fuel holder from above. Because the fuel holder at least partially surrounds the bottom part of the burner unit, this means that the fuel holder and burner unit can rapidly be slid apart. In other embodiments, the fuel holder can also be removed via the upper side of the burner unit.

The central opening in the fuel holder can have any desired shape, such as a block shape, but in certain embodiments the central opening has a predominantly cylindrical shape (the shape describing an ellipse, oval or circle in cross section). If this shape corresponds substantially to the external shape of the bottom part in question of the burner unit, a good fit can be provided between the fuel holder (that is to say the support which imparts the desired stability to the appliance) and the burner unit. In other embodiments, the burner unit has a shape with one or more protruding cams. This cam or these cams allow(s) the burner unit to be securely fastened to the fuel holder.

In a furdier embodiment, the appliance comprises a coupling element (which can in fact in certain embodiments comprise a number of coupling element parts, such as a "male" and "female" coupling element part, for example) which is to be detachably coupled to the fuel holder and the fuel supply for providing a fuel connection between the fuel holder and the burner unit. This allows fuel to be stored separately in the fuel holder and the burner unit. If the burner unit contains just a small amount of fuel at any given time and the remainder of the fuel is stored in a separate fuel holder, there is a relatively low risk of a large amount of fuel leaking, for example if the burner unit falls over.

In one embodiment, the coupling element is attached to the fuel holder and it comprises a safety facility which ensures that no fuel can leave the holder if the coupling element is not coupled to the burner unit in the correct manner. The safety facility may for example be a valve which is closed under a spring action. When coupled, the valve is opened so that fuel can be transferred from the fuel holder to the burner unit. In a further embodiment, the coupling element is provided on the fuel holder and/or on the fuel and/or air supply of the burner unit and the coupling element is configured to be coupled and uncoupled by sliding the burner unit in and out respectively. In the slid- in state, the fuel supply is automatically secured, while in the slid-out state the fuel remains safely confined in the fuel holder and/or the burner unit.

In certain embodiments, the appliance comprises at least one (hand-operated or electric) fuel pump for passing fuel from the fuel holder to the combustion chamber of the burner unit via the coupling element and the fuel supply. In embodiments of the heating appliance in which the fuel holder is positioned at a relatively high position with respect to the burner unit (for example at the centre or at the level of the top part of the burner unit), fuel can flow downward from the fuel holder, under the influence of gravity and without further displacement means, in the direction of the combustion space via the fuel supply. More specifically, the fuel is passed to a fuel reservoir which is provided in the burner unit and in which the underside of a burning wick can be attached so that the wick, as part of the fuel supply, becomes saturated with fuel.

However, in certain other preferred embodiments, the fuel level in the holder is just above the intended fuel level in the fuel reservoir and, even more preferably, the burner unit and fuel holder are embodied and positioned with respect to each other in such a way that the maximum fuel level in the fuel holder does not exceed the maximum admissible fuel level in the aforementioned reservoir of the fuel and/or air supply (module) of the burner unit. This benefits the safety of the appliance,

In, inter alia, embodiments of this type, a siphon mechanism can help to get the fuel into the burner unit. In certain embodiments, the heating appliance therefore also comprises a siphon mechanism which is configured for siphoning over fuel from the fuel holder to the burner unit, more particularly to the aforementioned fuel reservoir in the fuel and/or air supply (module). The siphon mechanism can form part of the coupling element mentioned in the present document, but it can also be implemented as a separate mechanism.

In a particularly advantageous embodiment, the siphon mechanism comprises:

- at least one fuel passage, for instance a pipe or conduit, extending between the fuel holder and the fuel reservoir of the fuel supply of the burner unit, the fuel pipe being arranged, when the fuel holder and the burner unit are coupled, to pass fuel from the fuel holder to the fuel reservoir;

- at least one air passage, for instance a pipe or conduit, which extends between the fuel holder and the fuel reservoir.

In embodiments of the invention, the (fuel tank of the) fuel holder is a substantially airtight compartment. The only transport of air or fuel to and from this compartment is through the air passage. A passage may be formed by a pipe, conduit, hose or similar element configured to allow an air/fuel flow between the holder and reservoir.

After the siphoning action has been initiated, fuel is passed over from the fuel holder to the fuel reservoir as a consequence of a higher fuel level in the fuel holder than in the reservoir.

When fuel is transferred from the fuel holder to the fuel reservoir, the air pressure in the fuel holder would decrease were it not for the fact that outside air, or at least air from the reservoir, can flow into the fuel holder via the air passage in order to substantially keep up the air pressure. If, however, the supply of air to the fuel holder is interrupted, for example as a result of the fact that the air passage is closed off as a consequence of the increase of the fuel level in the reservoir, the air pressure in the fuel holder does decrease so that the flow of fuel from the fuel holder to the reservoir ends at a given moment. This is used in a further embodiment of the invention in which the mouth of the air passage is located on the side of the fuel reservoir of the fuel and/or air supply (module) of the burner unit at a position (h) above the bottom of the fuel reservoir. The position is generally higher than the mouth of the fuel passage. The position (h) is in this case preferably selected in such a way as to correspond to the desired maximum fuel level (relative to the bottom of the fuel reservoir) in the fuel reservoir of the burner unit.

Hence, in an embodiment of the invention, the mouth of the air passage in the fuel reservoir is arranged at a height (h) essentially corresponding to the maximum fuel level in the fuel reservoir. More generally, the air passage is arranged in the fuel holder and fuel reservoir so as to interrupt passing fuel from the fuel holder to the fuel reservoir when the fuel level inside the fuel reservoir reaches a predefined maximum fuel level. In order, in the starting state, to prime (that is to say to start up) the siphoning, the pressure inside the fuel holder may be increased temporarily. In an embodiment of the wall of the fuel holder, or at least a part thereof, can be made at least partially of bendable material. The operator can then press-in the fuel holder somewhat, so that the pressure in the fuel holder increases (as a consequence of the reduction in size of the volume enclosed by the fuel holder) and the flow of fuel to the reservoir from the fuel holder is started. In order to prevent air to escape through the air passage during pressing in of the holder, the air passage may be connected to a one-way valve for passing an air flow from the fuel reservoir to the fuel holder and checking an air flow from the fuel holder to the fuel reservoir. In other embodiments other means are provided for temporarily increasing the pressure inside the fuel reservoir to prime the siphoning.

A further advantage of the use of the siphon mechanism in combination with the fuel holder and the fuel reservoir in the fuel and/or air supply (module) of the burner unit is that, in principle, no fuel connections under the fuel level are necessary, so that there is little risk of leakage. According to a further embodiment of the invention, the appliance comprises one or more air supply elements along which outside air can be fed in the direction of the combustion chamber, wherein a part of an air supply element is formed by the intermediate space between the outer side of the fuel holder and the outer side of the fuel and/or air supply (module) of the burner unit, at least if these are coupled to each other. Thus, the fuel in the fuel holder can be cooled via the supply of air that is necessary for the burning process.

In a further embodiment, the appliance comprises one or more air supply elements along which outside air is to be fed in the direction of the combustion chamber, wherein the inflow opening is situated at a position corresponding to the upper side of the fuel holder or higher and the outflow opening to the combustion chamber is situated at a position lower than the combustion chamber. This can ensure that the air required for the burning is taken in relatively high and thus reduces the drawing-in of dust and dirt lying on the support surface. This benefits the service life and the good operation of the appliance.

In a further embodiment, a stationary cyclone element is provided close to the outflow opening for causing the air flowing therealong to rotate and passing this air into the combustion chamber in the rotating state. The rotation of the air can ensure improved burning.

A further aspect of the invention relates to a portable heating appliance to be arranged on a support surface for providing combustion heat, such as for example (but without limitation to) the appliance as described hereinbefore, comprising:

- a support which is configured to be arranged on the support surface;

~ a burner unit which is to be detachably fastened to the support and comprises a combustion chamber for burning liquid or gaseous fuel and a fuel supply for passing fuel to the combustion chamber; - a conduction element arranged concentrically with the combustion chamber for receiving heat radiated from the combustion chamber, the heat being radiated either directly or indirectly via one or more intermediated concentric walls;

- a thermoelectric element connected to the conduction element for converting radiant heat from the conduction element into electrical energy.

The support may in this case also be a fuel holder for storing the fuel, but there may also be a separate fuel holder which does not form part of the support. As a result of the fact that the thermoelectric element for the largest part (or totally) receives heat by radiation only, the presence of the thermoelectric element has less influence, in most cases almost no influence, on the burning properties of the appliance. This may have a positive effect on the combustion properties of the appliance.In some embodiments wherein additional energy (except from the energy received from radiation) may need to be accumulated by the thermoelectric element, the appliance further comprises at least a conductive connection element between the outer wall of the combustion chamber and the conduction element. In this way it is possible to additionally receive heat by heat conduction from the intermediate wall to the thermoelectric component.

According to an embodiment the appliance may further comprising a generally cylindrical outer jacket, arranged concentrically with respect to the combustion chamber and around the conduction element, the outer jacket being provided with cooling fins, preferably cooling fins at both the inner surface and the outer surface of the outer jacket.

The electrical energy generated can be used for a number of purposes. The energy can for example be applied for charging a chargeable battery or storage battery of an apparatus to be externally connected to the burner, such as a mobile telephone. Alternatively or additionally tliereto, the electrical energy can be used for charging the batteries required by the appliance itself, for example when lighting the burner (in the form of a sparkover or via an incandescent filament). In one embodiment of the invention, the appliance comprises a first cylindrical heat conduction element which is placed at least partially around the discharge element and optionally recedes radially inward somewhat, a second at least partially cylindrical heat conduction element provided with an intermediate space around the first cylindrical heat conduction element, the thermoelectric element being placed in the aforementioned intermediate space.

In a further embodiment, a reflector, which prevents or reduces the transfer of heat via radiation between both heat conduction elements, is additionally attached. The heat conduction elements can be made of material displaying good thermal conductivity, such as aluminum metal.

In a certain embodiment, the first and second cylindrical heat conduction elements are arranged so as to be mutually displaced in the axial direction so that the outermost element, which ensures cooling, is not heated or is heated less intensively by the warm combustion gases.

In a further embodiment, the outer jacket of the second cylindrical heat conduction element is provided with one or more, preferably many, cooling fins. The second heat conduction element is preferably kept relatively cool. This can take place by arranging the second heal conduction element with respect to the air supply to the combustion chamber in such a way that supplied relatively cold outside air sweeps along the outer surface of the second heat conduction element in order to exert a cooling effect on this element.

According to one aspect of the invention, a fuel holder is provided for a heating appliance, the fuel holder being formed to at least partially surround the bottom part of the burner unit and to be stably placed on a support surface when fastened. According to a further embodiment, the fuel holder is a substantially pressureless fuel holder, meaning that the pressure in the holder is equal or substantially equal to the air pressure outside. This makes it possible to embody the holder in a relatively simple and possibly even bendable manner and benefits the safety of the appliance. According to a further embodiment, the fuel holder has a substantially planar underside. A planar underside allows the fuel holder (which also forms the support for the burner unit) to be placed in a stable manner on a planar support surface, such as a table, road, stretch of grass and the like.

In a further embodiment, the fuel holder is provided with an integrated or non- integrated handle. The handle can for example be formed by one or more notches for making the toroidal fuel holder thinner (less high and/or wide) at certain locations so that the holder can be grasped there more effectively by hand. Misassembly can be prevented if the aforementioned protruding cam shape of the fuel and/or air supply module fits into the central cylindrical-shaped opening having a cam shape in the fuel container exactly and in just one way. In certain embodiments, the fuel holder has an elongate shape, preferably also a relatively flat and/or low shape. This can promote stable placement of the holder on the support surface.

In a further embodiment, the fuel holder, or at least the upper side and/or underside thereof, is provided with one or more protrusions. The opposing side, that is to say the burner unit, can in this case be provided with one or more corresponding notches. The protrusions can engage with the notches, allowing the fuel holders to be centred with respect to one another when stacked. As a result of the fact that the fuel holders are stackable in these embodiments, they can be transported safely and efficiently. This can limit the logistical costs. In addition, the notches and protrusions can impart additional stability to the stacking.

As mentioned hereinbefore, the fuel holder can comprise a wall which is formed at least partially by material which can be bent by hand, at least material which can be pressed in and bends back again when it is no longer pressed in. Pressing in the holder by hand allows the size of the holder volume to be reduced.

The fuel holder can be embodied so as to be able to accommodate within it more than one burner element. In further embodiments of the invention, the fuel holder comprises a number of openings in which a corresponding number of burner units can be detachably fastened. The fuel holder can furthermore also be provided with a sealable filling opening in order to have the holder refilled after use by an authority appropriate for this purpose.

Further features and details of the invention will be clarified based on the following description of a few embodiments thereof. The description refers to the appended figures, in which:

Figure 1 is a schematic view of a support or fuel holder according to one embodiment of the invention; Figures 2a and 2b show in a schematic manner a fuel supply module (service module) of the burner unit according to one embodiment of the invention;

Figure 3 shows in a schematic manner a module with a combustion chamber of the burner unit according to one embodiment of the invention;

Figures 4a and 4b show in a schematic maimer assembled modules of a heating appliance. Figure 4a representing an assembly of the fuel holder from Figure 1 and the service module from Figure 2a, and Figure 4b representing the assembly from Figure 4a in combination with the combustion module from Figure 3;

Figure 5 is a transverse cross section of assembled fuel holder and service module (without combustion chamber module) of the embodiment of figure 4a;

Figure 6 shows in a schematic manner the conveyance of fuel via a siphoning action;

Figure 7 is a partially exploded perspective view of the fuel holder with a service module, combustion chamber module and a thermoelectric module placed thereon; Figure 8A is a perspective view of the thermoelectric module that can be arranged on the combustion chamber module;

Figure 8B is a longitudinal cross section, partly taken away, of the top part of the embodiment represented in Figure 7;

Figure 8C is a transverse cross section through the top part of the embodiment represented in Figure 7; Figure 8D shows a detail from the transverse cross section of Figure 8C.

Figures 9a and 9b show in a schematic manner another embodiment of a fuel supply module or service module of the burner unit; Figures 10a and 10b show in a schematic manner en elevational view and a side view another embodiment of a wick compartment module 140 according to the invention;

Figure 1 1a shows a view of a fuel holder 1 10 according to another embodiment of the invention;

Figure l i b shows the fuel holder of figure 1 1a wherein a service module of figures 9a and 9b has been mounted;

Figure 12a shows the fuel holder 1 10, service module 120 and wick compartment module 140 in a mounted condition, in an side view and a cross-section respectively. Figure 13a is a detailed perspective view of another embodiment of a combined thermoelectric module and combustion chamber module to be mounted on the wick compartment module; Figure 13b is a cross section of the module of figure 13a;

Figure 13c is a top view of the module of figure 13a; Figure 13d shows a detail from the transverse cross section of Figure 13c;

Figure 34 is a view of the appliance shown in figure 12A, wherein a thermoelectric /combustion chamber module has been mounted to the combined fuel holder, service module and wick compartment module; and

Figure 15 is a cross-section showing the assembled fuel holder, service module, wick compartment module, combustion chamber module and thermoelectric module according to the embodiment of figures 9a-14, in particular showing the air flows generated when the appliance is in use.

Figures 1-5, 7-8d show in a schematic manner a first embodiment of the present invention, while figures 9-15 relate to a second embodiment of the invention. Throughout the drawings the same reference numbers have been used to refer to the same or similar elements of both embodiments of the invention.

Figure 1 shows a support 10 for a heating appliance. The support has a double function: on the one hand, the support functions as a means to support the burner (which will be described in greater detail) of the appliance when the appliance is placed on a support surface, more specifically a generally flat and horizontal surface. For instance, the appliance may be placed on the ground, a table, a road, etc.. On the other hand, in certain embodiments, the support can be partially filled with fuel and thus functions as a fuel holder 10. The support 10 (referred to hereinafter also as the fuel holder) is preferably made of a sturdy yet somewhat flexible and relatively light material, such as plastics material (for example HDE or PET). For instance, in accordance with an embodiment of the invention wherein use is made of a siphon construction, the material may be made flexible enough to enable a person to press the holder manually in order to raise the pressure inside the holder. The material used should further be highly liquid and gas-tight because the support will contain fuel during use. In an advantageous embodiment, the fuel holder is manufactured using HDPE extrusion blow moulding technology, but other ways of manufacturing can also be used. In the present example, the support is embodied as a torus-like body surrounding a hole 14 at the centre of the support. This hole is a central opening that preferably is cam-shaped so that a so-called service module can be easily placed therein.

The fuel holder 10 is equipped with a closable fuel filling opening 1 1. This filling opening 1 1 can for example be closed off by means of a screw cap which is attached to a flange, which is provided with a screw thread, of the filling opening 1 1 . The filling opening provides access to the interior of the fuel holder 10 and can be used to fill the fuel tank 16 thereof. In embodiments of the invention the fuel tank occupies only a part of the interior of the fuel holder 10, while in other embodiments substantially the entire interior of the fuel holder 10 forms a fuel tank 16. In case the fuel tanks completely surrounds the service module (to be described hereafter) of the appliance, for instance if the fuel holder is generally toroidal, the fuel tank 16 may form one single reservoir surrounding the service module so that the weight of the fuel inside the tank may further stabilize the appliance when it is placed on a horizontal support surface. In the embodiment shown in figure 1, the filling opening is provided in the side of the fuel holder 10, so that when the fuel holder 10 is placed upright, the contents thereof can easily be filled with fuel via the filling opening 1 1.

A second access 12 to the fuel tank 16 is provided close to the filling opening 1 1. This access 12 comprises two openings: a fuel outflow opening 8 and an air inflow opening (not shown). The access further comprises an element provided with an external screw thread for connecting thereto a fuel supply, more specifically a fuel/air coupling element 51 (shown in figure 7 and, more schematically, in figure 6). This element will be described in greater detail hereinafter. The fuel/air coupling element 51 comprises a fuel supply pipe 77 for passing fuel from the fuel tank 16 to the fuel reservoir of the burner unit and an air supply pipe 76 for supplying air from the fuel reservoir of the burner unit to the fuel tank 16. A one-way valve 74, which allows air to flow to the fuel tank 16, but prevents air from flowing out of the fuel tank 16, is provided below the air/inflow opening and is to be connected to the air supply pipe. Provided below the fuel outflow opening is a fuel pipe part 80 (Figure 6), with an open end which is situated close to the base of the fuel container for taking in fuel located at the base of the fuel tank 16, so that fuel can still be taken even when the fuel level in the fuel tank 16 is already relatively low. hi an exemplary embodiment, the fuel (supply) pipe and the air (supply) pipe are fastened to a fastening element, such as a cap provided with an internal screw thread, of the fuel/air coupling element 51 , and parts thereof are introduced into the fuel tank 16 when the fuel/air coupling element 51 is fastened to the fuel holder 10. This example has the advantage that the pipes are reusable and are not thrown away together with an empty fuel holder 10, for example, since they can be stored separately from the fuel holder. In other examples the fuel and air pipes are integrated with the fuel holder or the burner unit or partly in the fuel holder, partly in the burner unit.

The bottom of the support 10 is locally planar and provided with somewhat protruding parts or bumps, in such a way that the support can be placed in a stable manner on a substantially flat surface, such as a table or the ground. Shallow cavities 13, which correspond to the bumps at the bottom of the support for making a number of supports 10 simply and stably stackable, are provided at the bottom of the support 10. The fuel holder (support) 10 of the present example is provided on one side, opposite the side having the filling opening 1 1 and access 12, with a notch or lowered portion 15, This lowered portion allows the support to be easily grasped in the uncoupled state, when the support is detached from the burner unit. The support pail is embodied to be so low at the site of the lowered portion 15 that the operator can easily grasp it using one hand and the support part then functions as a handle for the support. An additional mechanical or electromechanical module 50 (cf. figure 4b), which is for example provided with a number of mechanical safety facilities and/or electronic circuits with which the safety of the burner can be increased (for example a fall-over protector or solenoid which is activated via the level sensor for fuel in the fuel and/or air supply module of the burner unit, etc.), can also be placed in the space of this lowered portion 15.

In an exemplary embodiment, the fuel holder 10 has a diameter of at most 20, at most 30 or at most 40 centimetres, as a result of which the fuel holder is easily portable even when the support 10 is filled with fuel.

Figures 2a and 2b are a three-dimensional (3D) representation and a 3D transverse cross section respectively of a fuel supply module 20, herein also referred to as the service module. This module is preferably made substantially of metal or hard plastics material. The parts thereof that are positioned, when the heating appliance is installed, in the region of the combustion chamber are preferably made of a non-burnab!e material having a high melting point, with respect to the flame temperature, such as aluminium or steel,

A first air supply 39, also referred to in the present document as a chimney, formed by a cylinder wall 38 and a support part 37 placed thereon, is positioned centrally in the service module 20. Referring to figures 5 and 15, air is drawn in, guided along the bottom portion of the appliance en then travels upward in the air supply 39 to flow through the perforations in the cylinder wall 38 towards a combustion chamber 99. A cyclone element 26 is located at the bottom of the air supply (chimney) 39, just above the base plate 32, for causing a rising air flow in the chimney 39 to rotate. Details of the air supply and combustion chamber will be described later.

A wick 27, which is displaceable with respect to the cylinder wall 38 in the vertical direction, is attached around the cylinder wall 38. The wick is substantially rotationally symmetrical, and is surrounded by a wick holder 28 at a defined height of the wick. Vertical displacement of the wick holder 28 causes concomitant sliding of the wick 27 with respect to the cylinder wall 38. The wick holder 28 is connected to a shaft 25 via a mechanism which is known per se, in such a way that rotation of the shaft 25 causes vertical displacement of the wick holder 28 and thus of the wick 27.

The underside of the wick 27 is located substantially in the region of the base of a substantially annular fuel reservoir 35 which is enclosed by the cylinder wall 38, a reservoir wall 62, the cover plate 29 and the reservoir base 63 of the fuel and/or air supply (module) 20. The fuel reservoir 35 is sufficiently large to give the wick 27 room to fold up when the wick is displaced downward as far as it will go. The fuel reservoir can contain an amount of fuel that is preferably just enough to effectively wet the wick and to allow effective burning.

Referring to figures 2a, on the outer side of the reservoir wall 62 and the inner side of the suirounding wall 65 of the service module 20 a plurality of fin elements 36 are formed. The surrounding reservoir wall 65 surrounds the reservoir wall 62 and forms a double wall, as it were, with the reservoir wall 62.

Referring to figure 5, in case the fuel holder is attached to the service module, air can move through the space present between the fuel holder and the service module downward, the flows between these two walls 62,65 , flows through between the base plate 32 and the reservoir base 63 below the fuel reservoir 35 and exits below the cyclone element 26 below the chimney 39, along which the gradually warming-up air will rise again. The air flows within the heating appliance will also be described with reference to Figure 5.

A groove containing an O-ring 31 , made of a durable resilient material such as rubber, is provided in the aforementioned cover plate 29 of the fuel and/or air supply module 20 so as to be able to connect a combustion chamber module 40 to the fuel and/or air supply module 20 using an air-tight connection. Holes 30 are also provided in the cover plate 29 for attaching screws or bolts which can be used to detachably fasten the aforementioned modules to one another.

A fuel inflow opening 21 and an air outflow opening 22 are provided in the cover plate 29. A fuel pipe 77, which is connected at an upper end to the fuel inflow opening 21 and has at the lower end 81, above the bottom wall or reservoir base 63, an outflow opening 101 for supplying fuel to the fuel reservoir 35, is located within the fuel reservoir 35. An air pipe 76 which is connected at an upper end to the air outflow opening 22 and has an inflow opening for receiving air from the fuel reservoir 35, is also located within the fuel reservoir 35. The lower end 82 of the air pipe 76 is located at a specific height (h, see also Figure 6) above the reservoir base 63 of the fuel reservoir 35. As soon as die level of the fuel in the fuel reservoir 35 exceeds this height h, the air pipe 76 will no longer receive any air. This will prevent the air from being able to escape from the fuel reservoir 35, which is otherwise substantially air-tight, as a result of which the air pressure will increase as the fuel level continues to rise; this counteracts the siphoning action, which will be described in greater detail with reference to Figure 6, with which the fuel is forced into the fuel reservoir 35, in such a way that the fuel level will no longer continue to rise at a given moment. As such, this device forms a protector against excessive filling of the fuel reservoir 35.

The manner in which the fuel and/or air supply module 20 operates will be described in greater detail with reference to Figures 5 and 6.

In an embodiment other than that shown here, a fan, to which electrical energy is applied via a battery, is provided at the site of or close to the cyclone element 26. An advantage of this embodiment is that a fan can initiate a stronger air flow; this can lead to more efficient burning and better cooling of the burner. The drawback is that electrical energy is necessary to power the fan, which energy must be supplied by a separate power source such as a battery.

Figure 3 shows in a schematic manner a combustion chamber module 40. The module comprises a support plate 46 to be fastened to the service module 20. The support plate 46 is provided with holes 45 which correspond to the holes 30 of the fuel supply module or service module 20 for detachably securing modules 20 and 40 to each other, for example with the aid of screws or bolts and nuts. Like the fuel and/or air supply module 20, the combustion chamber module 40, and in particular the parts positioned in the region of the combustion chamber, are made of a material which is non-burnable and has a high melting point, such as aluminium or steel.

A first cylindrical body 44, which partly encases the cylinder wall 38 and wick 27 of the fuel supply module 20 when the modules 20 and 40 are assembled, is placed on the support plate 46. An annular part 47 with an electrical lighting mechanism 43 known per se for causing a flame to be lit in the combustion chamber is positioned above the cylindrical body 44. This electrical lighting mechanism 43 can be connected to a battery (not shown), for example a chargeable battery located in a housing on the support 10. Referring to figures 5 and 13b, the combustion chamber is defined between on the one hand the perforated inner wall 38 and/or a wall 103 essentially extending in line with the perforated wall 38 and a perforated outer wall 44 (and/or 104).. Consequently, the combustion chamber 99 is a annular compartment, bounded sideways by two perforated cylindrical walls. From the bottom side a wick 27 (that is wetted with fuel in the fuel reservoir located beneath the combustion chamber) may be moved upward or downward in the combustion chamber to regulate the combustion. Figure 5 is a schematic transverse cross section of an assembly made up of the fuel holder 10 and service module 20. Between the cover plate 29 and the top of the fuel holder 10 is a substantially annular gap 100 (figure 4a) through which air can be drawn (direction P 1-P2) to the space between the fuel and/or air supply module 20 and the fuel holder 10. This air flows, on the one hand, along the reservoir wall 62 and, on the other hand, along a wall of the fuel holder 10 and wall 65. Attached along the exterior of the reservoir wall 62 are fin elements 36 which pass the air (direction P₃) into a gap between the reservoir wall 62 and the surrounding reservoir wall 65. From there, the air exits (direction P₄) below the cyclone element 26 below the chimney 39. While the air flows along this route, the air absorbs heat from the fuel reservoir 35 and the fuel tank 16, which it thus cools. The air, which now gradually warms up, will rise again along the cyclone element 26, and the blades of the cyclone element 26 will cause the rising air to rotate somewhat. This rotation of the air contributes to optimum mixing between the fuel and air in the combustion chamber (not shown) positioned above the chimney 39.

Referring to figure 15, air needed for the combustion may arrive both from the outer side (i.e. via de space between flange 105 and support plate 46 (direction Ρπ) and via wall 104 (direction P12) ) and the inner side (i.e. via the space between the fuel holder and service module (direction Ρ<_¾ and P₇), the chimney 39 of the service module (direction Pg) and through the perforations of the wall 103 of the combustion chamber module 1 1 1, direction P₉), which has a positive effect on the combustion characteristics in the combustion chamber 199. The heat may be discharged via the upper plate 42. The top of the module 1 1 1 with the upper plate 42 is configured to allow an object to be placed thereon, for example a pan. The upper plate 42 is provided with openings for discharging heat, air and combustion gases.

Figure 4a shows in a schematic manner a fuel holder 10 containing therein and fastened thereto a fuel supply module 20. The fuel holder 10 encases the bottom part of the fuel supply module 20 that is placed in the hole 14, as a result of which this module is positioned relatively stably and cannot rapidly fall over. The module 20 is detachably fastened to the fuel holder 10, for example via screws. Figure 4b shows in a schematic manner that fuel holder 10 has fastened thereto a fuel supply or service module 20 and, above that, a combustion chamber module 40. An electromechanical module 50, which is placed in or on the lowered portion 15, is also provided. The electromechanical module 50 acts on the shaft 25 of the fuel supply module 20 and is provided with a rotary knob 52 which is mechanically connected to the shaft 25 when the electromechanical module 50 is fastened, so that the wick 27 can be slid up and down by turning the rotary knob 52. In an electromechanical module 50, the module is connected to a battery, for example a chargeable battery which is placed in a battery housing in or on the fuel holder 10, and configured to automatically slide the wick 27 downward in certain cases, for example if the formation of too much heat is detected by a heat sensor, for example, in or close to the combustion chamber module 40, in order to temper the flame in the combustion chamber.

The fuel/air coupling element 51 of the fuel supply module 20 is fastened to the access 12 (cf. figure 1) of the fuel holder 10. The access 12 comprises a fuel outflow opening and an air inflow opening. The fuel/air coupling element 51 ensures a fluid comiection between the fuel outflow opening of the fuel holder 10 and the fuel inflow opening 21 of the fuel reservoir 35 of the module and air connection between the air inflow opening of the fuel holder 10 and the air outflow opening 22 of the module 20. It is advantageous to configure the fuel supply module 20 and the combustion chamber module 40, which together form important components outside the fuel holder of the heating appliance, as separate modules. For example, if the combustion chamber 40 wears more rapidly than the fuel supply module 20, only this First module can be replaced, and more expensive complete replacement of the heating appliance is not necessary.

Owing, inter alia, to a suitable, relatively light material selection and a defined diameter of the heating appliance, for example at most 10, 20 or 30 centimetres, the heating appliance is portable in an exemplary embodiment.

Advantages of the device according to this example thus include the fact that the inflowing air cools both the fuel in the fuel reservoir 35 and the fuel tank 16, and that this air is also made to rotate for optimum mixing with the fuel; this may improve the efficiency of the burner. Another advantage of the device shown is that air is drawn in from above (above the cover piate 29 of the service module 20 and support plate 46 of the combustion chamber module 40 and therefore from a relative high position, spaced away from the support surface at which the appliance has been placed) and not from below, since air which is drawn in from below a burner can be polluted with dust or sand particles, for example; this has an adverse, for example wearing, effect on the burner.

Figure 6 shows in a schematic manner the siphoning action with which fuel is forced from the fuel tank 16 of the fuel holder 10 to the fuel reservoir 35 of the fuel supply module 20 via the fuel/air coupling element 51. In the abstract representation of Figure 6, the volume 70 corresponds to the fuel tank 16 and the volume 72 corresponds to the fuel reservoir 35. The fuel pipe 77 has a lower portion inside the volume 70 and a lower portion inside the volume 72, whereas the air pipe 76 has a lower portion 82 inside the volume 72. In the embodiments shown in figure 1 the fuel/air coupling element 51 comprises the parts of the pipes 76,77 between the volumes 70,72, while the portions 80 and 81/82 are part of the fuel holder and fuel reservoir, respectively.

The normal siphoning action is as follows. When the fuel level in the volume 70 is higher than in the volume 72, fuel will flow, because the volumes communicate via the fuel connection 80, 77, 81, from the volume 70 to the volume 72 until the fuel levels are at the same height. This siphoning action may have to be started up, for example by creating temporary excess pressure in the volume 70. Because the volume 70 is closed off, air will have to flow back to the volume 70, in this case from the volume 72 via the air connection 82, 76, 74, while fuel flows from 70 to 72. The end of the air connection 74 is formed as a one-way valve which allows only air flow from the air pipe 76 to the volume 70 in order to prevent the possible fonnation of an inverted air flow which might be accompanied by an undesirable inverted fuel flow.

The end of the air pipe 82 is located at a defined height h above the base of the volume 72 corresponding to the reservoir base 63. When the fuel level in the volume 72 rises to above this height, the air pipe 82 will not be able to accommodate any more air in order to return it to the volume 70. As a result, the air pressure in the volume 72 will increase and the siphoning action will eventually stop. In this way, the maximum fuel level in the volume 72 (the fuel reservoir 35) is thus limited to a predefined height. It is advantageous to define this height in such a way that sufficient fuel is allowed in the fuel reservoir 35 for good functioning of the heating appliance, but not so much that hazardous situations can arise, for example when the heating appliance falls over.

The heating appliance formed by the modules 10, 20 and 40 functions as follows. Fuel is siphoned over from the fuel holder 10 to the fuel reservoir 35 of the fuel supply module 20 via the siphoning action described with reference to Figure 6. The siphoning mechanism is configured in such a way that the siphoning action is interrupted before the fuel reservoir 35 of the fuel supply module 20 becomes too full. In an exemplaiy embodiment, the siphoning action is initiated by the user of the heating appliance by pressing on a flexible wall of the fuel holder 10. This creates an excess pressure, as a result of which the first fuel is forced from the fuel tank 16 of the fuel holder 10 to the fuel reservoir 35 of the fuel supply module 20. After this, the siphoning mechanism runs in principle without intervention on the part of the user. In other embodiments special means are provided to temporarily increase the pressure in the fuel reservoir 16 to start the siphoning action, for instance a hand-operated pump.

The wick 27 of the fuel supply module 20 is dipped into the fuel which is present in the fuel reservoir 35, as a result of which the fuel is absorbed by the wick 27. The production and functioning of the wick 27 are known per se. The fuel enters the combustion chamber 99 of the combustion chamber module 40 via the wick. The wick can be set via the shaft 25 to an optimum height for optimum burning.

Via the device for producing an air flow that has been described with reference to Figure 5, relatively cold ambient air is drawn in from above (above the cover plate 29 of the fuel supply module 20) and passed along the fuel reservoir 35 and fuel tank 16 so that the ambient air can cool the fuel which is present there. The air is then passed through below the fuel reservoir 35 and it subsequently rises successively through a cyclone element 26 and a chimney 39 to the annular combustion chamber where the air is mixed with the fuel brought through the wick. During the ignition of this mixture, heat energy is released and combustion gases are produced. The combustion gases are passed outward mainly via the base plate 42. Figures 7 and 8A-8D show an embodiment of a heating appliance which is provided with a thermoelectric element which can be used to convert heat into electricity. Figure 7 is a partially exploded perspective view of the embodiment and Figure 8A is a perspective view of a part of the embodiment shown in Figure 7. The figures show that an inner cylinder 184 is concentrically arranged around the previously mentioned second cylindrical body 41. An outer cylinder 85 is concentrically arranged around the inner cylinder, the outer cylinder 85 being somewhat displaced in the vertical direction with respect to the inner cylinder 84. In other words, the outer cylinder 85 extends less far in the vertical direction than the inner cylinder 84. More particularly, at least a part of the inner cylinder 84 is provided downstream of the combustion chamber, so that the absorbing by the inner cylinder of heat originating from the combustion space has little influence on the burning in the combustion chamber. The outer cylinder 85 is provided on its outer surface with the previously mentioned cooling fins 86. Together with a wall 93 provided on the outer cylinder 85, the cooling fins 86 define a number of air channels 92 positioned next to one another (Figure 8D) along which air can be passed.

The inner cylinder 84 accommodates a part of the heat that is generated in the combustion chamber and transmits this heat in the direction of the outer cylinder 85. A substantially planar guide plate 90, which passes on a large part of the heat which is absorbed by the inner cylinder 84, is provided between the inner cylinder 84 and the outer cylinder 85. A thermoelectric element 89, which can be used to convert the aforementioned heat in the guide plate into electrical energy (according to the Peltier- Seebeck principle) is connected to the guide plate 90. The thermoelectric element 90 can be connected to an electronic circuit which can be used to charge up a storage battery or a set of chargeable batteries. It is also possible to use the electrical energy generated for operating or charging up one or more external apparatuses, such as a mobile telephone, a radio, a fan and the like. The previously mentioned inner and outer cylinders 84, 85 have a varying wall thickness in a certain embodiment. The greater the wall thickness is, the greater the heat flow may generally be. The heat flow is preferably the greatest at the level of the thermoelectric element, The heating appliance according to embodiments of the invention can be used in a broad range of ways, such as for preparing food, heating a room and/or for generating electricity. It is important that the appliance is portable (weighs typically less than 10 kg) and can be stably arranged on almost any desired support surface. In the embodiment shown in figures 9-15 a service module 120 (shown in figures 9a and 9a) can be removably attached to a fuel holder 1 10 (shown in figure 1 la). On top of the combined fuel holder 1 10 and service module 120 (the combination being shown in attached condition in figure 1 la) a wick compartment module 140 (shown in figures 10a and 10b) can be mounted to arrive at the assembly shown in figure 12a.

Above the wick compartment 133 (cf. figure 15) the combustion chamber 199 is to be placed to allow the fuel evaporated from the wick and mixed with the air flow to allow for combustion thereof. In figure 15 the situation is shown wherein the combined combustion chamber module and thermoelectric module 1 1 1 has been removably mounted to the assembly of figure 1 1c. The module 1 1 1 is shown in more detail in figures 13a-d.

Referring to figure 13b, a generally ring-shaped combustion chamber 199 is formed between a the inner perforated cylindrical wall 103 and the outer perforated cylindrical wall 104. Similar to the wall 41 and the upper plate of the embodiment of figure 1, a cylindrical wall 1 13, concentrically with the combustion chamber and at substantially the same height, is positioned laterally with respect to the wall 104. The cylindrical wall 1 13 is formed to have an upper part extending above the combustion chamber/chimney 39. The cylindrical wall 1 13 acts as a heat conduction element and may pass on heat to a heat conduction plate 125. In the embodiment shown the heat received by the inner cylindrical heat conduction wall 113 is primarily or totally received by radiation from the combustion chamber 199. In this embodiment there is practically no conduction of heat from the combustion chamber to the conduction wall 1 13, for instance caused by a conductive connection between the walls of the combustion chamber and the inner heat conduction wall. One of the advantages is that the combustion inside the combustion chamber is hardly disturbed. In other embodiments, however, a conductive connection is present and the heat transferred from the combustion chamber to the conduction plate 125 is partly caused by radiant heat, partly by conduction of heat. The conductive element can be formed by the earlier mentioned upper part of the conduction wall 1 13. The conduction wall 1 13 in this embodiment can be formed to contact the outer combustion wall 104, the inner combustion wall 103 and any of the intermediate walls (of present) between the combustion chamber and the heat conduction plate 125. The upper part of the conduction wall can also be configured to impede or stop the upward air flow inside the chimney 39. This forces the air to pass the perforations of the inner combustion wall 103. Concentrically with the cylindrical heat conduction wall 1 13 a cylindrical heat shield or reflector 1 18 may be arranged and concentrically with the reflector 1 18 a cylindrical wall 1 16 acting a heat conduction element may be arranged. The heat shield 1 18 is arranged so as to prevent or reduce the transfer of heat via radiation between the inner heat conduction element 1 13 and the outer heat conduction element. To this end it surrounds the inner heat conduction wall 1 13 and it is isolated from the heat conduction plate 125.

In order to keep the cylindrical wall 1 16 relatively cool, the wall is provided at its inner surface with a plurality of first guiding vanes 1 19 and at its outer surface with a plurality of second guiding vanes 1 17. Finally a housing wall 121 is arranged concentrically with the cylindrical wall 1 16. Between the housing wall 121 and the cylindrical wall 1 16 a number of channels 127 and between the cylindrical wall 1 16 and heat shield 1 18 a number of channels 128 is formed for guiding relatively cool air in an upward direction (direction Pio, figure 15).

A substantially planar heat conduction plate 125 is attached (in a non-conductive manner) to the heat shield 1 18 and to the inner heat conduction wall 1 13. At the inner part, heat radiated from the combustion chamber 199 is radiated to the inner heat conduction wall. The heat passed to the shield / reflector 1 18 is reflected back to the inner heat conduction wall in order to save energy. The heat received by the inner heat conduction wall 1 13 is then conducted directly to the conduction plate 125. At the outer part, the plate 125 is cooled by the cooling action of the air guided along the channels 127,128 of the cylindrical wall 1 16. The plate 125 is connected to a thermoelectric element 131 , which can be used to convert the aforementioned heat in the plate 125 into electrical energy (according to the Peltier-Seebeck principle). The thermoelectric element 131 in turn can be connected to an electronic circuit which can be used to charge up a storage battery or a set of chargeable batteries. It is also possible to use the electrical energy generated for operating or charging up one or more external apparatuses, such as a mobile telephone, a radio, a fan and the like.

If the cooling action of the air flow generated as a result of convection is insufficient in certain circumstances, for instance when the ambient temperature is relatively high, then the cooling action may be permanently or temporarily supported by a fan (not shown in the figures). The fan can be accommodated in a fan housing 129 and may be configured to generate air flows in a plurality of channels 1 12 between cooling fins 123 provided on the cylindrical wall 1 16 to provide for additional cooling of the guiding plate 125. In a further embodiment the fan is configured to guide the air along the cooling fins 1 17, 1 19 as well.

As has been described hereinbefore at length, the fuel and/air supply module comprises in certain embodiments a coupling element, a reservoir and a wick which jointly supply fuel to the combustion chamber via a siphoning action and also an air supply which draws in air from above the fuel holder, toward the combustion chamber, via a "chimney" effect. The fuel and the air meet in the combustion chamber and burning can take place. In other embodiments, the fuel and/or air supply module comprises a pump which injects fuel into the combustion chamber at a very low pressure and a fan which blows air, at a likewise low pressure, toward the combustion chamber and which draws in air from above the fuel holder.

The invention is not limited to the embodiments described hereinbefore. A broad range of combinations thereof are possible. The figures are schematic by nature and may not be used to derive absolute or relative dimensions therefrom. The rights applied for are set out in the appended claims.

Claims

I . Portable heating appliance to be arranged on a support surface for providing combustion heat, the appliance comprising:

- a support which is configured to be arranged on the support surface;

wherein the support also forms a detachable fuel holder for storing fuel, the appliance further comprising a second fuel supply for feeding fuel from the fuel holder to the fuel reservoir, wherein the fuel holder at least partially surrounds the bottom circumferential pari of the burner unit, when die fuel holder is fastened to the fuel reservoir.

2. Appliance as claimed in claim 1 , wherein the fuel holder is an exchangeable fuel holder, removably attached to the burner unit.

3. Appliance as claimed in claim 1 or 2, wherein the first fuel supply comprises a wick, partly placed in the fuel reservoir, the fuel reservoir preferably having a substantially annular shape to accommodate the lower end of the wick.

4. Appliance according to claim 1 or 2, wherein the fuel holder, optionally also the fuel reservoir, is substantially annular or toroidal and the burner unit is slidable into or out of the associated central opening.

5. Appliance according to one of the preceding claims, wherein the second fuel supply comprises a coupling element which can be detachably coupled to the fuel holder and the fuel reservoir for providing a fuel connection between the fuel holder and the burner unit.

6. Appliance according to Claim 5, wherein the coupling element is provided on the fuel holder and/or the fuel reservoir of the burner unit and wherein the coupling element is configured to connect the fuel supply to the fuel holder or to disconnect the fuel supply from the fuel holder by sliding the burner unit in and out of the fuel holder, respectively.

7. Appliance according to Claim 5 or 6, comprising a fuel pump for passing fuel from the fuel holder to the combustion chamber of the burner unit via the coupling element and the fuel supply.

8. Appliance according to one of the preceding claims, comprising a siphon mechanism, preferably forming part of the coupling element according to Claim 5 or 6, for forcing the fuel out of the fuel holder to the fuel supply of the burner unit under a siphoning action.

9. Appliance according to Claim 8, wherein the siphon mechanism comprises:

10. Appliance according to claim 9, wherein the mouth of the air pipe in the fuel reservoir is arranged at a height corresponding to the maximum fuel level in the fuel reservoir.

1 1. Appliance according to claim 9 or 10, wherein the air pipe is arranged in the fuel holder and fuel reservoir so as to interrupt passing fuel from the fuel holder to the fuel reservoir when the fuel level inside the fuel reservoir reaches a predefined maximum fuel level.

12. Appliance according to any of claims 9-1 1, wherein the air passage is connected to a one-way valve for passing an air flow from the fuel reservoir to the fuel holder and checking an air flow from the fuel holder to the fuel reservoir.

13. Appliance according to any of claims 9- 12, wherein, when the fuel holder is coupled to the burner unit, the mouth of the air pipe is located on the side of the fuel reservoir of the burner unit at a position (h) which is higher than the mouth of the fuel pipe.

14, Appliance according to any of the preceding claims, wherein the wall of the fuel holder is made at least partially of a bendable material for enabling the initiation of the siphoning action by pressing in the holder wall.

15. Appliance according to one of the preceding claims, comprising one or more air supply elements along which outside air can be fed in the direction of the combustion chamber, wherein a part of an air supply element is formed by the intermediate space between the outer side of the fuel holder and the outer side of the burner unit.

16. Appliance according to one of the preceding claims, comprising one or more air supply elements along which outside air is to be fed in the direction of the combustion chamber, wherein the inflow opening is situated at a position corresponding to the upper side of the fuel holder or higher and the outflow opening to the combustion chamber is situated at a position lower than the combustion chamber.

17. Appliance according to claim 15 or 16, wherein the air supply elements at least partially form part of the fuel and/or air supply module.

18. Appliance according to Claim 16 or 17, wherein a stationary cyclone element is provided close to the outflow opening for causing the air flowing therealong to rotate and passing this air into the combustion chamber in the rotating state.

19. Appliance according to one of the preceding claims, wherein the combustion chamber has a substantially annular shape, the appliance further comprising:

- a cylindrical conduction element arranged concentrically with the combustion chamber for receiving heat radiated from the combustion, the heat being radiated from the combustion chamber either directly or indirectly via one or more intermediate concentric walls; - a thermoelectric element connected to the conduction element for converting radiant heat from the conduction element into electrical energy.

20. Appliance according to any of the preceding claims, comprising a conductive connective element in contact with the outer wall of the combustion chamber and the conduction element for providing the thermoelectric element with conduction heat.

21. Appliance as claimed in claim 19 or 20, comprising a generally cylindrical outer jacket, arranged concentrically with respect to the combustion chamber and around the conduction element and/or the heat shield, the outer jacket being provided with one or more cooling fins.

22. Appliance according to one of the preceding claims, wherein the fuel holder is a substantially pressureless fuel holder.

23. A portable heating appliance to be arranged on a support surface for providing combustion heat, preferably an appliance according to one of the preceding claims, the appliance comprising:

- a support which is configured to be arranged on the support surface;

- a burner unit which is to be detachably fastened to the support and comprises a combustion chamber for burning liquid or gaseous fuel and a fuel supply for passing fuel to the combustion chamber, the combustion chamber preferably having a substantially annular shape;

- a conduction element arranged concentrically with the combustion chamber for receiving heat radiated from the combustion chamber, the heat being radiated either directly or indirectly via one or more intermediated concentric walls;

24. Appliance as claimed in claim 22 or 23, further comprising a heat shield around the conduction element.

25. Appliance according to any of the preceding claims, comprising a conductive connective element in contact with the outer wall of the combustion chamber and the conduction element for additionally receiving heat by heat conduction.

26. Appliance as claimed in claim 23, 24 or 25, further comprising a generally cylindrical outer jacket, arranged concentrically with respect to the combustion chamber and around the conduction element and/or heat shield, the outer jacket being provided with cooling fins, preferably cooling fins at both the inner surface and the outer surface of the outer jacket.

27. Appliance according to any of claims 23-26, wherein the support is also a fuel holder for storing the fuel.

28. Fuel holder for an appliance according to one of the preceding claims, wherein the fuel holder is formed to at least partially surround the bottom part of the burner unit and to be stably placed on a support surface when fastened.

29. Fuel holder according to claim 28, wherein the fuel holder has a substantially planar underside.

30. Fuel holder according to claim 28 or 29, provided with a handle, wherein the handle is preferably formed by one or more notches.

31. Fuel holder according to any of the claims 28-30, wherein the fuel holder has an elongate shape, preferably also a relatively flat and/or low shape.

32. Fuel holder as defined according to one of the claims 28-31 , wherein the upper side or underside is provided with one or more protrusions and the opposing side is provided with one or more corresponding notches for centring the fuel holders with respect to one another when stacked up.

33. Fuel holder according to any of the claims 28-32, comprising a wall which is at least partially formed by manually bendable material for reducing the size of the holder volume by pressing-in the wall.

34. Fuel holder according to any of claims 28-33, comprising a number of openings in which a corresponding number of burner units can be detachably fastened,

35. Fuel holder according to any of claims 28-34, wherein the heating appliance is a cooking appliance.

36. Fuel holder according to any of claims 28-35, wlierein the heating appliance is configured for heating a room.