The fuel element holder can be placed in a lower combustion chamber space.

The casing is designed to form one or more air passageways between the outer surface of the fuel chamber and the inner surface of the casing, said air passageway or passageways extending upwards and functioning to conduct heating air flows.

A heat-generating arrangement of this kind is particularly constructed to heat small confined spaces and may also be used in small confined spaces to which particular fire safety requirements and like regulations apply.

The inventive heating arrangement finds particular use in leisure boats, caravans, tents and like structures, and also within civil defense applications.

It will be understood that by the term"fuel element"as used with reference to the present invention is meant fuel elements that will burn and generate heat without, at the same time, generating troublesome fumes or smoke. The term fuel element will therefore be interpreted to include so- called heating candles, cresset-like torches and similar discrete elements that comprise paraffin and/or stearin fuel.

The combustible material is normally enclosed in a metal container.

BACKGROUND OF THE INVENTION Earlier known heat-generating arrangements intended for heating small spaces are normally comprised of separate devices adapted to burn paraffin, alcohol or gasol. The fumes and smoke generated by such devices as the fuel burns is both troublesome and unpleasant and, as a rule, must be led away from the thus heated small confined space.

Those arrangements and devices that are currently available are relatively expensive, require technical expertise on the part of the user and, in the majority of cases, have a heating capacity which is much greater than that required to heat small spaces.

The majority of these known arrangements and devices require access to a supply of electricity and/or to means for ventilating harmful combustion fumes and residual products generated by combustion of the fuel.

With regard to the special features of the present invention, it should be mentioned that it is known to use stearin candles, so-called heating candles and like elements for illumination and heating purposes. Burning of such fuel elements has no detrimental effect on the environment and does not generate harmful or unpleasant fumes.

Swedish Published Specification SE-B-451 754 teaches a heat- emitting casing for so-called heating candles. The heating candle is placed in an intended space in a glass enclosure, which may be sealed by means of a glass bottom-piece screwed thereon. The heating candle is lit by inserting a match through an air supply hole such as to generate friction between the head of the match and a rubbing surface on the

hole. The match is therewith ignited and, in turn, lights the candle. The lit candle will then begin to heat the air enclosed in the glass case and the air will rise and flow through an exhaust air opening as a result of the change in the density of the air, at the same time as unheated air will flow into the casing through the air supply holes.

U. S. Patent Specification 4,971,027 teaches a portable camping heater that includes an upper chamber which accommo- dates liquid to be heated, and a lower chamber placed immediately beneath the upper chamber. An elongated chimney having corrugated side walls extends from the bottom chamber and up through the upper chamber so that liquid in the upper chamber surrounds the chimney when the heater is in use. A solid fuel is burned in the bottom chamber so as to heat the surrounding air, which then flows up through the chimney.

Heat is transferred through conically shaped side walls of the corrugated chimney, so as to heat the liquid.

This heater is considered to be compact and portable.

SUMMARY OF THE INVENTION TECHNICAL PROBLEMS In view of the fact that the technical deliberations required of a person skilled in this particular art in providing a solution to one or more technical problems involve initially a realization of the measures and/or the sequence of measures that must be undertaken on the one hand and the choice of the means required in this respect on the other hand, it will be seen that the technical problems listed below are relevant to the development of the present invention.

When considering the current state of the art as described above, it will be seen that a technical problem resides in providing with the aid of simple means an arrangement for

generating heat in small spaces with the use of burnable material enclosed in a metal container, where said arrange- ment is constructed so as to fulfil special fire safety requirements.

A further technical problem is one of constructing an heating arrangement that can be used readily in leisure boats, caravans, tents, etc., despite burning with an open flame.

Another technical problem resides in providing a heat- generating arrangement that is able to use a number of simple fuel elements, such as heating candles, that meet the actual heating requirement and which burn without harmful effect on the environment and without the fumes being troublesome or unpleasant when released into the small space together with heated air flows.

Another technical problem is one of realizing the signifi- cance of and the advantages that are afforded when the combustion chamber is extended upwards with the aid of an upwardly tapering combustion-chamber funnel, and when the casing also tapers upwardly such as to form air passageways in which the air flows are heated.

A technical problem also resides in realizing the signifi- cance of and the advantages that are afforded by providing the upper part of the fuel-chamber funnel with one or more apertures for the release of air heated in the combustion chamber in mixture with the gases of combustion generated when burning the fuel element.

Yet another technical problem is one of realizing the significance of and the advantages afforded by providing the upper part of said casing with one or more apertures for the release of air flows heated in air passageways and in the combustion chamber and the combustion-chamber funnel.

Another technical problem resides in realizing the signifi- cance of and the advantages that are obtained when two air passageways are positioned solely as an inner and an outer or front air passageway with each positioned on a respective opposite side of the combustion-chamber funnel.

Another technical problem is one of realizing the signifi- cance of extending an inner air passageway along and beyond both the combustion chamber and the combustion-chamber funnel and to position said inner air passageway adjacent a wall- part of the small, confined space to be heated.

A further technical problem is one of realizing the signifi- cance of and the advantages that are afforded by extending a front or outer air passageway solely beyond the combustion- chamber funnel.

Another technical problem is one of realizing the signifi- cance of providing the combustion-chamber funnel with one or more air through-passing apertures, preferably within the outer air passageway.

A technical problem also resides in realizing the signifi- cance of positioning the aperture or apertures within the lower part of the outer air passageway, and then to particu- larly position said apertures at a distance from the bottom opening of the air passageway that corresponds to between 10 and 50%, such as 15-25%, of the total length of said passage- way.

Another technical problem is one of realizing the signifi- cance of causing the upper apertures in the combustion- chamber funnel to face towards an air-flow conducting plate or like element and to deflect and guide a heated air flow in the inner air passageway along said conductor plate, while directing a heated air-flow in the outer air passageway at

right angles, or essentially at right angles, to the conduc- tor plate.

Yet another technical problem resides in realizing the significance of and the advantages afforded by providing a fuel element holder in the form of a separate box-like container or unit that can be inserted into and withdrawn from the lowermost part of the combustion chamber.

Another technical problem is one of realizing the signifi- cance of and the advantages afforded by providing the bottom part of the holder with one or more apertures for an upward supply of air flows intended for combustion.

Another technical problem is one of realizing the signifi- cance of providing at least one of the end-wall related wall parts of the combustion chamber? with one or more apertures for sideways supply of air flows intended for combustion.

Another technical problem is one of realizing the signifi- cance of using in the fuel element holder non-combustible intermediate pieces and of ensuring that these intermediate pieces are disposed and dimensioned to hold and position the heat-generating candles in a predetermined orientation within the holder.

In respect of the above application, it will be seen that a technical problem resides in realizing the significance of providing the fuel element holder with a front air-flow guiding upstanding border and to provide conditions which enable a fully inserted holder to be latched or locked in position by means of one or more lugs or like elements.

Another technical problem is one of realizing the signifi- cance of providing the upper part of the combustion chamber with at least one upwardly inclined surface part which terminates at the bottom part of the fuel-chamber funnel and

to position said surface part immediately above a number of rows of discrete fuel elements.

Another technical problem is one of realizing the signifi- cance of and the advantages afforded by giving the inner air passageway a larger cross-sectional area within the region of the lower part of the combustion-chamber funnel than in its upper or uppermost part.

Still another technical problem is one of realizing the significance of and the advantages that are afforded by providing the bottom of the holder with a large number of apertures with a selected number disposed around one or more heat-generating candles and adapted to generate air flows around respective candles.

SOLUTION With the intention of solving one or more of the aforesaid technical problems, the present invention is based on a heat- generating arrangement that includes a fuel element holder, a combustion chamber and a casing which surrounds the combustion chamber either completely or partially, wherewith the fuel element holder can be placed in a lower space in the combustion chamber and the casing is dimensioned to form one or more air passageways between the outer surface of the combustion chamber and the inner surface of the casing, wherewith said air passageways extend upwardly to conduct upwardly directed heating air flows.

The inventive heating arrangement is mainly characterized in that the combustion chamber is extended upwardly by means of a combustion-chamber funnel that tapers upwardly in one plane, in that the casing also tapers upwardly in the same plane so as to form said air passageways, in that the upper part of the combustion-chamber funnel includes one or more apertures for the release of air heated in the combustion

chamber and mixed with combustion gases generated by combus- tion of the fuel elements used, and in that the upper part of said casing includes one or more apertures intended for the release of air flows heated in the air passageways and in the combustion chamber and the combustion-chamber funnel.

According to preferred embodiments that lie within the scope of the present invention, the fuel elements are heat-generat- ing candles or corresponding devices.

The air passageways are each positioned on a respective side, the inner and the outer side, of the combustion-chamber funnel.

An inner air passageway extends beyond both the combustion chamber and the combustion-chamber funnel, and an outer air passageway extends obliquely beyond solely the combustion- chamber funnel.

According to one embodiment of the invention, the combustion- chamber funnel includes one or more apertures, preferably within the outer air passageway, where said aperture or apertures is/are at least orientated within the lower part of the air passageway. In this latter case, the apertures are positioned at a distance from the lower opening of the outer air-passageway that corresponds to between 10 and 50% of the total length of the air passageway.

According to another embodiment of the invention, the apertures provided in the upper part of the combustion- chamber funnel face towards a conductor plate which functions to deflect and guide heated air flows in the inner air passageway.

In one embodiment, the fuel element holder has the form of a separate box-like container or unit that can be inserted

into and withdrawn from the bottom part of the combustion chamber.

In a further embodiment of the invention, the bottom part of the fuel-element holder is provided with one or more through- penetrating apertures for a vertically upwardly directed supply of combustion air.

At least one of the mutually opposite end-wall related wall- parts of the combustion chamber will include one or more apertures for the sideways supply of combustion air.

The fuel-element holder will also preferably include fire- resistant intermediate pieces which allow heat-generating candles to be orientated and/or locked in a predetermined pattern in the holder.

The holder will conveniently include a raised front border and be constructed to enable it to be latched or locked in a fully inserted position, with the aid of one or more lugs or like elements.

The combustion chamber shall also include at least one upper, obliquely and upwardly extending surface parts located immediately above a number of rows of discrete fuel elements.

This principle is also proposed with respect to the inner air passageway, which has a larger cross-sectional area within the region of the lower part of the combustion-chamber funnel than in its upper part.

The bottom of the holder will conveniently be provided with a plurality of apertures positioned around one or more heat- generating candles and adapted to generate air flows around respective candles.

Those advantages that are primarily characteristic of the inventive arrangement reside in the provision of conditions which enable a small confined space to be heated with fuel elements that burn with an open flame, and particularly in confined spaces in which stringent fire safety regulations prevail, for instance in leisure boats, caravans, tents and like places.

The heat and the warm air currents generated by the inventive arrangement provide a comfortable atmosphere as the fuel elements burn.

The desired heating effect can be readily achieved by appropriate selection of the number of fuel elements used, while the heating time can be readily adapted by choosing an appropriate element.

The main characteristic features of an inventive heat- generating arrangement are set forth in the characterizing clause of the following Claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in more detail with reference to embodiments that include significant features of the invention and also with reference to the accompanying drawings, in which Figure 1 is a perspective view of an inventive arrangement mounted on a wall structure that defines a small, confined space;

Figure 2 illustrates the arrangement in Figure 1 in larger scale, and shows a fuel element holder withdrawn from the arrangement, said fuel elements being shown in the form of heat-generating candles; Figure 3 is a sectioned side view of a first embodiment of an inventive arrangement; Figure 4 is a sectioned side view of a second embodiment of an inventive arrangement; and Figure 5 illustrates from above part of a bottom-part of a holder with heat-generating candles placed in holes provided in said bottom-part, said holes functioning to generate air flows around respec- tive candles.

DETAILED DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED Figure 1 is thus a perspective view of an inventive heat- generating arrangement 1 placed on part of a wall A1 adjacent a corner of a small confined or limited space A.

As will be evident from Figure 2, the arrangement 1 includes a holder 2 for a number (six) fuel elements 3 in the form of heat-generating candles.

Each of the six illustrated fuel elements 3 comprises an outer metal shell, such as 3', filled with paraffin or stearin wax 3"and a centrally placed wick 4.

The illustrated arrangement includes a combustion chamber 6 which is integrated with an overlying combustion-chamber funnel 6b, and a casing 7 which surrounds the combustion 6 and the funnel 6b either completely or partially.

The holder 2 can be placed in a lower space 6a of the combustion chamber 6.

The casing 7 is constructed to form one or more air passage- ways 8,9, in the illustrated case two such passageways, of rectangular cross-section and defined between the outer surface 6'and 6"of the fuel chamber 6 and the inner surface 7'and 7"of the casing 7.

The air passageways 8,9 will thus extend upwardly, with the air passageway 8 extending vertically and the air passageway 9 extending obliquely upwards, such as to meet one another within an upper part 10 and form a mixed part of an outgoing, heated air flow 11.

The combustion-chamber funnel 6a includes one or more apertures 61 within the extension of the outer air passageway 9, said apertures having the form of a row of circular holes 61 in the illustrated case. The apertures may be between three and eight in number.

In the illustrated case, the apertures 61 are positioned in the lower part of the air passageway 9.

It is preferred that the apertures 61 are positioned at a distance from the bottom opening 9a of the air passageway 9 that corresponds to between 10 and 50% of the total length of the air passageway, this distance corresponding to between 20 and 25% in the illustrated case.

The combustion-chamber funnel 6b also includes upper aper- tures 62, which are arranged to face towards an air-flow conducting plate 71. These apertures may be between three and eight in number.

The heated air flow passing through the air passageway 8 is guided parallel with and along the conductor plate 71,

whereas the heated air flow in the air passageway 9 is guided at right angles to the conductor plate 71, while an air flow heated in the combustion chamber 6 and the combustion-chamber funnel 6b and mixed with combustion gases generated by the combustion of said fuel elements is guided as an air flow to pass between and be mixed with said two air flows so as to commonly form the exiting air flow 11.

As will be seen from Figure 2, the fuel element holder 2 of the illustrated embodiment has the form of a separate box- like unit which can be inserted into (in the arrowed direc- tion) and with drawn from the lower part 6a of the combustion chamber.

The bottom part 2a of the holder 2, a part of which bottom- part is shown in Figure 1, includes one or more apertures, in the illustrated case six apertures 21-26 which are positioned around a candle container 3'to form a number of upwardly directed combustion air flows.

The vertically upward air flows initially function to cool the candle container 3'and contribute towards centering the flame from the wick 4.

At least one of the mutually opposite, end-wall related wall parts of the combustion chamber includes one or more aper- tures through which combustion air is delivered laterally to the combustion chamber. These apertures are referenced 81 in one end-wall part 6b and 81'in the opposite end-wall part 6e.

A number of partition pieces or intermediate pieces, of which two are referenced 27,28, are provided for holding and/or orientating the heat-generating candles (such as 3') in a predetermined position on the bottom 2a of the holder 2.

The holder includes a front upstanding wall 2b and is adapted to take a position in which it is locked or latched by means of one or more lugs 31,32.

The combustion chamber 6 has an obliquely and upwardly extending surface part 6f located immediately above a row of discrete fuel elements. This row row fuel elements elements posi- tioned close to the upstanding wall 2b.

As will be evident from Figure 4, the inner air passageway 8 has a larger cross-sectional area 80 in the region of the lower part of the combustion-chamber funnel 6b than in the upper part of said passageway.

This has been achieved by providing the combustion chamber 6 with an obliquely and upwardly extending surface part 6g.

The upper part 2b'of the upstanding wall 2b is comprised (see Figure 3) of an extension of the outer surface of the surface-part 6f so as to conduct the air flow B to be heated in the air passageway 9.

The air flow C to be heated in the air passageway 8 shall pass through one or more apertures 81".

The larger cross-sectional area 80 is formed by said surface part 6g and there generates a vortex zone adjacent the hottest part of the combustion chamber 6.

The proposed distance of between 10 and 50% may very well be between 15-30%, such as about 20%.

Although the air through-flow apertures have been shown in the form of holes 81,81'and 81"and also in the form of holes 61,61', there is nothing to prevent the apertures having different shapes to that illustrated or to be greater or fewer in number. Further apertures may also be provided

above and/or beneath the illustrated apertures, depending on desired changes in the air flows within the arrangement.

Further apertures may conveniently be provided in the fuel- chamber funnel above or beneath those illustrated.

It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodi- ments thereof and that modifications can be made within the scope of the inventive concept as defined in the following Claims.